Newsgroup: sci.electronics
document_id: 52434
From: et@teal.csn.org (Eric H. Taylor)
Subject: Re: HELP_WITH_TRACKING_DEVICE

In article <00969FBA.E640FF10@AESOP.RUTGERS.EDU> mcdonald@AESOP.RUTGERS.EDU writes:
>[...]
>There are a variety of water-proof housings I could use but the real meat
>of the problem is the electronics...hence this posting.  What kind of
>transmission would be reliable underwater, in murky or even night-time
>conditions?  I'm not sure if sound is feasible given the distortion under-
>water...obviously direction would have to be accurate but range could be
>relatively short (I imagine 2 or 3  hundred yards would be more than enough)
>
>Jim McDonald

Refer to patents by JAMES HARRIS ROGERS:
958,829; 1,220,005; 1,322,622; 1,349,103; 1,315,862; 1,349,104;
1,303,729; 1,303,730; 1,316,188

He details methods of underground and underwater wireless communications.
For a review, refer to _Electrical_Experimenter_, March 1919 and June 1919.

Rogers' methods were used extensively during the World War, and was
unclassified after the war. Supposedly, the government rethought this
soon after, and Rogers was convieniently forgotten.

The bottom line is that all antennas that are grounded send HALF of
their signal THRU the ground. The half that travels thru space is
quickly dissapated (by the square of the distance), but that which
travels thru the ground does not disapate at all. Furthermore,
the published data showed that when noise drowned out regular
reception, the underground antennas would recieve virtually noise-free.

IF you find this hard to believe, then refer to the work of the
man who INVENTED wireless: Tesla. Tesla confirmed that Rogers' methods
were correct, while Hertzian wave theory was completely "abberant".

----
 ET   "Tesla was 100 years ahead of his time. Perhaps now his time comes."
----

Newsgroup: sci.electronics
document_id: 52446
From: w1gsl@athena.mit.edu (Steven L. Finberg)
Subject: New England Ham - Electronic Fleamarket Dates  ** 1 April update  **




New England Area Major Flea Market    ***  DATES  ***      1993        P 1 of 2
All events are Ham Radio/ Electronic related except ~_____~ 
*******************************************************************************
1993                                                    Contact          Source
*******************************************************************************

3 April Upper Saddle River NJ CRRC   9-3 sell @8     Jack W2EHD 201 768 8360 D

4 April Southington CT SARA @HS $20@6:3 $10@8:3 $3@9      N1GCV 203 621 6191 F

17 April Nashua NH NE Antique RC $5@8 $1@9 @ Res Ctr Church Ray 508 865 1290
 
18 April Cambridge MA       FLEA at MIT                    Nick 617 253 3776 F
               buy $2@9A  sellers $10/sp@7A $8in adv  $35 for season pass
               3rd Sunday Each Month April thru October   

18 April Webster MA ECARA @ Pt Breeze Rest $3 tables $10   Gary 203 974 2564 F

18 April Agawam MA HCRA @ Southwick Rec Ctr $3@9A     Bob W1ZGP 203 653 0715 F

23,24,25 April Dayton OH  adm $11  sell $30/50++       evenings 513 767 1107 F

2 May Yonkers NY  @Lincoln HS                       Otto WB2SLQ 914 969 1053 A

7-8 May Rochester NH Hoss Traders @FG ex13 off rt 16 $5 noon fri  WA1IVB sase

15 May N Smithfield RI RIFMRS @VFW Main St 8A        Rick K1KYI 401 725 7507  

16 May Cambridge MA       FLEA at MIT                      Nick 617 253 3776 F

16 May Pittsfield MA @Taconic HS Sell $5@7 Buy $2@8 Cliff W1SJV 413 743 3334  

21-22-23 May Rochester NY ARRL-NY Conv @ Monroe FG  Harold K2HC 800 724 8515 F

5 June S Burlington VT                             Mitch WB2JSJ 802 879 6589

6 June Newington CT @HS Flea                         Les KA1KRP 203 523 0453

12 June Bangor ME Pine St ARC @Hermon ES 146.34/94 8AM-$2 Roger 207 848 3846 

20 June Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F

17 July Nashua NH NE Antique RC $5@8 $1@9 @ Res Ctr Church  Ray 508 865 1290

17 July Union ME @ Fairground $3@7AM State Conv    Skeet KA1LPW 207 622 2915  

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LAST UPDATE 3-29-93 de W1GSL                                           P 1 of 2
*******************************************************************************
Additions/ Corrections  via Internet  w1gsl@athena.mit.edu
                            US Mail   W1GSL POB 82 MIT Br Cambridge MA 02139
                                      SASE for updated copy as issued.



1993                                                   Contact           Source
*******************************************************************************

18 July Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F
                   3rd Sunday Each Month April thru October   

24 July Manchester NH NHARA @HI 8A$4 NE DC 300Ts (no TG) WB1HBB 603 432 6011 F

8 Aug White Planes NY WECAfest                      Sarah N2EYX 914 962 9666 D

8 Aug Wellseley MA WARS+BARS @Babson College         Barry WN1N 508 877 4947 T

14 Aug St Albans ME  @ Snow Mobile Club             Hitch K1HHC 207 796 2282  

15 Aug Cambridge MA          FLEA at MIT                   Nick 617 253 3776 F

29 Aug Fall River MA BCRA                            Tom WA1LBK 508 674 4163 T+

11 Sept Windsor ME @ Fairground $3@7AM             Skeet KA1LPW 207 622 2915  

12 Sept Gaithersburg MD FAR @Mg Cty FG $5@6A- $7TG Nancy Drahim 703 691 0078 J

12 Sept S Dartmouth MA SE Mass ARA 8A-                Dan N1HCV 508 933 0678  +

19 Sept Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F

19 Sept Sandy Hook CT Candlewood ARA               Harold KB1US              A

25 Sept Greenbush ME  WCSN/BARC @WCSN xmtr          Ed Cockburn 207 732 4366  

26 Sept Framingham MA @ HS $12@8 $5@9 $2@10          Barry WN1N 508 877 4947 F

26 Sept Yonkers NY Metro 70 ARC                     Otto WB2SLQ 914 969 1053 A

15,16 Oct Rochester NH Hoss Traders @FG ex13 off rt 16 $5 noon fri      K1RQG 

17 Oct Cambridge MA          FLEA at MIT                   Nick 617 253 3776 F

13 Nov Plymouth MA Mayflower RC @Mem Hall 9-3 sell@8   Jim NM1F 508 747 2224  
                   
14 Nov Branford CT SCARA @intrm sch                 Brad WA1TAS 203 265 9983 T
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LAST UPDATE 3-29-93 de W1GSL                                           P 2 of 2
Source F= Flyer  J= John Roberts list   A= ARRL list   WR NV 73 CQ QST = Mags
       T= tentative early info    D= W1DL      + = new info this month
This list has been compiled from many sources.  While we believe the info to 
be accurate the author can not be responsible for changes or errors.  
Check with the sponsoring organizations for more details. 
This list will be posted monthly to Usenet if additions have been made. 
Mailed copies are sent when additions are made.
*******************************************************************************
Additions/ Corrections  via Internet  w1gsl@athena.mit.edu
                            US Mail   W1GSL POB 82 MIT Br Cambridge MA 02139
                                      SASE for updated copy as issued.

Newsgroup: sci.electronics
document_id: 52464
From: et@teal.csn.org (Eric H. Taylor)
Subject: Re: Electronic Tesla Coils

In article <1993Mar25.161909.8110@wuecl.wustl.edu> dp@cec1.wustl.edu (David Prutchi) writes:
>In article <C4CntG.Jv4@spk.hp.com> long@spk.hp.com (Jerry Long) writes:
>>Fred W. Culpepper (fculpepp@norfolk.vak12ed.edu) wrote:
>>[...]
>>A couple of years ago I put together a Tesla circuit which
>>was published in an electronics magazine and could have been
>>the circuit which is referred to here. This one used a
>>flyback transformer from a tv onto which you wound your own
>>primary windings. It also used 2 power transistors in a TO 3
>[...]
>10 years ago I built a 1'000,000 volt Tesla, and the thing was VERY
>spectacular, but besides scaring/amazing friends (depending on their
>knowledge of Science), and generating strong EMI, I never found anything
>useful that could be done with it ...  Is there any real-world application
>for Tesla coils today ?
>
>David Prutchi

First of all, realize that Tesla invented AC power generators, motors,
transformers, conductors, etc. Technically, *ALL* transformers are Tesla
coils.  In general though when someone refers to a Tesla coil, they mean
an "air core resonant transformer". The TV flyback version Tesla
coil (see the _Encyclopedia_of_Electronic_Circuits_ V3, 106-1 for
diagram) has NOT an air core. It is of a class of circuit called
"Oscillating Shuttle Circuit" (OSC). Generally OSC's are highly
efficient, but this version uses transistors and resistors,
which are very lossy devices. Typically Tesla used active
reactances instead of passive resistors, so that he could achieve
efficiencies of 99.5%, and better. The usual application of an air-core
resonant transformer, or of an OSC, is to produce strong EMI
for wireless broadcasts. How well do you think your computer
screen would work if we removed the HF HV Tesla (flyback) coil
from it? If we were to remove from our homes and industries all
Tesla coils, our lights would go dark, our cars would sputter
and die, our radios would go silent, our industries would grind
to a halt, and we would have to go back to using coal for heat,
gas for lamps, horses for transportation, steam for power, and
telegraph for communication. Is that real world enough for you???????

GET THE MESSAGE! WE WOULD NOT HAVE 1/100 THE CONVIENIENCES WE HAVE
TODAY IF NOT FOR TESLA. GIVE CREDIT WHERE CREDIT IS DUE!

If it had been up to Edison, we'd still be in the 19th century.
(flame me at your own peril. I'm very good at putting edison down).

----
 ET   "Tesla was 100 years ahead of his time. Perhaps now his time comes".
----

Newsgroup: sci.electronics
document_id: 52717
From: jml@norman.vi.ri.cmu.edu
Subject: Re: Radar Jammers And Stealth Cars

Eric H. Taylor writes
> ... If you are determined
> to go faster, get an airplane. They dont have speed limits.

Just don't make a habit of buzzing your local airport at >200 knots
(250 knots if you're flying a jet).  :-)

Newsgroup: sci.electronics
document_id: 52718
From: harpe@netnews.louisville.edu (Mike Harpe)
Subject: WANTED: Protel EasyTrax for the MAC

The title says it all.  Contact me via EMAIL if you would can help me out...

Mike Harpe
University of Louisville

P.S.  I KNOW IT IS DISCONTINUED.  I want someone who would like to sell
      an old copy.
-- 
Michael Harpe, Programmer/Analyst      Information Technology, Ormsby Bldg.
harpe@hermes.louisville.edu            University of Louisville
(502)588-5542                          Louisville, Ky. 40292
"He's not a man, he's a remorseless eating machine!" - The Simpsons

Newsgroup: sci.electronics
document_id: 52719
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: What is Zero dB????

sehari@iastate.edu (Babak Sehari) writes:

>Similarly, people usually use dB for dBm. Another common mistake is spelling
>``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
>``Bell'' company, the mother of AT&T and should be capitalized.

Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the 
original Bell.  For example, SouthWestern Bell is a deciBell.

And the measure of current, Amp, is actually named after both the AMP company
and the Amphenol company.  Both companies revolutionized electronics by
simulatenously realizing that the performance of connectors and sockets 
were affected by the amount of current running through the wires.

The Ohmite company was the first to characterize resistances by numbers, thus
our use of the Ohms...


Alexander Graham Bell, actually, is where Bell came from...  



Actually, Bel refers

>                          With highest regards,
>                               Babak   Sehari.

>-- 
-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  | 
Pasadena, CA 91126 |   OS/2: The operating system of tomorrow, today.
+1 818 449 5457    |   

Newsgroup: sci.electronics
document_id: 52721
From: blakey@ug.cs.dal.ca (Jason Blakey)
Subject: Site for projects

	Does anyone out there know of any ftp sites which deal with 
electronics projects, plans, etc?  Any response appreciated.:)
JB
-- 
 ............................................................................ 
                      Jason Blakey -> blakey@ug.cs.dal.ca 

Newsgroup: sci.electronics
document_id: 52722
Subject: ACCESS BUS (was I2C bus)
From: srgxnbs@grace.cri.nz

From:	MX%"Andy.Macrae@Corp.Sun.COM"  6-APR-1993 06:48:34.96
To:	SRGXNBS
CC:	
Subj:	Re: I^2C bus and long haul serial (also Axlo

Return-Path: <Andy.Macrae@Corp.Sun.COM>
Received: from Sun.COM by GRV.GRACE.CRI.NZ (MX V3.1C) with SMTP; Tue, 06 Apr
          1993 06:48:29 +1300
Received: from Corp.Sun.COM (lemay.Corp.Sun.COM) by Sun.COM (4.1/SMI-4.1) id
          AA24280; Mon, 5 Apr 93 11:48:08 PDT
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          11:47:28 PDT
Date: Mon, 5 Apr 93 11:47:28 PDT
From: Andy.Macrae@Corp.Sun.COM (Andrew MacRae)
Message-ID: <9304051847.AA05710@grendal.Corp.Sun.COM>
To: srgxnbs@grace.cri.nz
Subject: Re: I^2C bus and long haul serial (also Axlo
CC: Andy.Macrae@Corp.Sun.COM
content-length: 693

In article <1pii04INNk6t@zephyr.grace.cri.nz> you write:
> Whats required to get onto the ACCESS bus? The nice thing about the
> i2c is that most i/o requires one 8 ... 16 pin DIL chip, ie its cheap
> and easy. Anyone can design a bus, trouble is most buses require a
> host of interface chips and often on-board intelligence.

Bruce,
	For the latest information on Access.Bus call the Access.Bus
Industry Group at (408) 991-3517.  Also, Sun will be hosting the next
meeting of the group on April 19th, here in Mountain View.  For some reason
I am not able to post to any newsgroups today, so please feel free to pass
this information on yourself as you see fit.

						Andrew MacRae


Newsgroup: sci.electronics
document_id: 52723
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Re: Jacob's Ladder

g92m3062@alpha.ru.ac.za (Brad Meier) writes:

> Hi, I'm looking for a circuit, that is called a "Jacob's Ladder".
> This little box is usually seen in sci-fi movies.  It consists of 
> two curves of wire protruding into the air, with little blue sparks
> starting at their base (where the two wires are closer to each other),
> moving up the wires to the top, and ending in a small crackling noise. 
> 
> Could anyone supply me with the schematic for the innards of this box?
> 
> Thanks in advance
> Mike
> 
> (Please reply by email to g90k3853@alpha.ru.ac.za)
> 
> --
>  |  / |  | ~|~ /~~\  |  | ~|~ /~~\  |~~\  /~~\         The KnightOrc 
>  |/   |\ |  | |   __ |__|  | |    | |__/ |         g92m3062@hippo.ru.ac.za
>  |\   | \|  | |    | |  |  | |    | |  | |      "When it's over I'll go home,
>  |  \ |  | _|_ \__/  |  |  |  \__/  |  |  \__/    until then, I stay!" - Me

 
        I'd like any accumulated information on this as well please.
 
                Thanks.
 
_________________________________________    
    _____                                |
   |     |   |                           |
 =========== |    Baden de Bari          |
  | o   o |  |                           |
  |   ^   |  | baden@sys6626.bison.ca    |
  |  {-}  |  | baden@inqmind.bison.ca    |
   \_____/   |                           |
-----------------------------------------


Newsgroup: sci.electronics
document_id: 52724
From: schellew@wu2.wl.aecl.ca (Wayne Schellekens)
Subject: WANTED: DRAM Controller for use with MC68HC16

For an upcoming project I want to use 4 Megs of DRAM configured as two 2
Meg banks of 16 bit data.  I was wondering if anyone out there knows of a
DRAM controller which will handle refreshing the data.  It's ok if the
controller doesn't handle bank switching - that part is easy.

The only controllers I know of are the ones out of the National
Semiconductor DRAM Management Handbook (1988 edition) eg. DP8429.  I would
like to know if another manufacturer produces one which may be easier to
implement in my circuit.

BTW, if anyone is wanting to hook up DRAM to a microcontroller, Dallas
Semiconductor makes a neat chip: the DS1262 Serial DRAM Nonvolatizer
Chip.  It uses the SPI (I2C) bus and refreshes/controls up to 16Mx1 of DRAM
memory.  It can use an external battery to refresh the DRAM when the
power is off.  Price is $11.75 from Dallas (quan 1).  I wish I could use
this chip but its maximum SPI clock rate is 1 MHz (too slow for me...).

Thanks in advance,

Wayne Schellekens
<schellew@wu2.wl.aecl.ca>
-- 
Wayne Schellekens, VE4WTS          Internet: schellew@wu2.wl.aecl.ca
AECL Research                         AX.25: VE4WTS@VE4KV.#WPG.MB.CAN 
Whiteshell Laboratories        Twisted pair: (204)753-2311 x2317

Newsgroup: sci.electronics
document_id: 52725
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: HV diodes

In article <1pohuq$4sq@grouper.mkt.csd.harris.com>, wdh@grouper.mkt.csd.harris.com (W. David Higgins) writes:
|> I believe the only thing that needs correction, Mr. Vanderbyl, is your
|> attitude.

Nope, Mr. Myers has found the bad mistake and posted a correction, thank God.

|> Acting the child won't gain you any favors or make a

Who's acting?

|> positive impression with anybody.  Ghod knows you've make an impression
|> on me;  just not a positive one.

Oh no, I haven't impressed Mr. Higgins.


Newsgroup: sci.electronics
document_id: 52726
From: rajan@cco.caltech.edu (Rajan Ranga)
Subject: An external timer

I was wondering if anyone knows of a chip that that is similar to
the internal timer 0 on the Intel 80C188?  I want a timer that has
a Maxcount A and B and the output should the same as Intel's timer.  I called
Intel and they told me that they don't make such a chip.  Any suggestions
are welcome.  Thanks in advance.

Rajan Ranga
E-mail: rajan@cco.caltech.edu

Newsgroup: sci.electronics
document_id: 52727
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Re Using old databooks

In article <1993Apr3.110048.4636@hemlock.cray.com> kilian@cray.com (Alan Kilian) writes:
>> jeh@cmkrnl.com
>
>This is almost exactly the reason I keep only the latest databook around.
>Too many times last years books turn into three years ago and the data
>in them doesn't match the current production parts.
>TANSTAAFL,
>                             -Alan Kilian

BUT... If you are in the habit of trying to repair old and obsolete
machines, the old data books are a goldmine of information you can
not get anywhere else. If you are trying to find a modern replacement
for an obsolete part, the original specs really come in handy. Design
out of the new books but save the old ones (or donate them to a ham).

If anybody in Phoenix disagrees, I'll drive over and help them 'get rid'
of all their old data books.

John 
(450 data books and growing)




Newsgroup: sci.electronics
document_id: 52728
From: timd@fenian.dell.com (Tim Deagan)
Subject: Homebuilt PAL (EPLD) programer?

Anyone know a reasonable circuit for programming PALs?  I am interested
in programming a wide range of EPLDs but would be happy with something 
that could handle a 22V10 or thereabouts.

Thanks in advance,
--Tim

---
{{{{{{{{{{{{{{{{{{{{{ timd@fenian.dell.com }}}}}}}}}}}}}}}}}}}}}}}}}}}}
             Rev. Tim Deagan - Official Obnoxious Poster
No one but me is responsible for anything I write, believe in or preach
* "It is difficult to free fools from chains they revere." - Voltaire *


Newsgroup: sci.electronics
document_id: 52729
From: robert.desonia@hal9k.ann-arbor.mi.us (Robert Desonia) 
Subject: A/D board BUS SPEED probl


C >Hi:
C >I have a 486DX2-66MHz computer to use with an A/D board
C >for data acquisition on an AT bus...I'm having problems.
C >The AT bus runs at 12.5 MHz - correct?  So there should
C >be no bus speed conflict. But I read somewhere that the
C >new 486DX2-66 MHz CPU runs on a 33 MHz bus - is that for
C >the local bus or the AT bus also - if so then I have a problem.
C >^^^^^^^^^^^^^^^^^^^^^^^^^^^
C >When I run on non-turbo-mode the speed goes to 8 MHz and the
C >A/D doesn't work.  Please mail your views!  Thanks.
C >Vincent
C >cyl5@musica.mcgill.ca
C >

The STANDARD AT bus (ISA) runs at 8MHz, not 12.5 MHz, but some 
non-stnadard ISA buses do have higher clock rates, but be careful, since 
some boards don't work with faster than standard rates.  For instance, my 
486 has adjustable AT bus speeds, and my PAS16 audio card chokes when I do 
AD data acquisition with a bus speed faster than 10MHz.

The fact that non-turbo-mode speed A/D doesn't work is weird.  You may 
have a motherboard with a hardware 'bug'.  

33 MHz bus on the 486DX2 66 does refer to the local bus.  FYI: the AT bus 
operates asynchronously, and is linked to the local bus via a 'bus 
interface', which is one function that your 'chipset'.

-rdd

---
 . WinQwk 2.0b#0 . Unregistered Evaluation Copy
 * KMail 2.95d W-NET HQ, hal9k.ann-arbor.mi.us, +1 313 663 4173 or 3959
                                                     
----
| HAL 9000 BBS:  QWK-to-Usenet gateway  | Four 14400 v.32bis dial-ins    |
| FREE Usenet mail and 200 newsgroups!  | PCBoard 14.5aM * uuPCB * Kmail |
| Call +1 313 663 4173 or 663 3959      +--------------------------------+
| Member of EFF, ASP, ASAD  * 1500MB disk * Serving Ann Arbor since 1988 |

Newsgroup: sci.electronics
document_id: 52730
From: robert.desonia@hal9k.ann-arbor.mi.us (Robert Desonia) 
Subject: Re: PC Parallel I/O


R >>>JD> ALL PC parallel ports that are compatable with the IBM standard,
R >>>JD> including the original IBM adaptor, are bi-directional.

NOT ALL PARALLEL PORTS ARE BI-DIRECTIONAL WITHOUT MODIFICATION.

My experience with the standard old zenith parallel port in their 
original 286s proves that.  They had the input direction disactiviated by 
tieing them R/W select line of the circuit to Vcc.  To make it bi ( which 
I did ) I had to modify it by scraping off the trace and solder a jump to 
the proper location.  I thought that this was just lazy on the part of 
Zenith ( they were not Zenith-Bull Group at that time).

-rdd

---
 . WinQwk 2.0b#0 . Unregistered Evaluation Copy
 * KMail 2.95d W-NET HQ, hal9k.ann-arbor.mi.us, +1 313 663 4173 or 3959
           
----
| HAL 9000 BBS:  QWK-to-Usenet gateway  | Four 14400 v.32bis dial-ins    |
| FREE Usenet mail and 200 newsgroups!  | PCBoard 14.5aM * uuPCB * Kmail |
| Call +1 313 663 4173 or 663 3959      +--------------------------------+
| Member of EFF, ASP, ASAD  * 1500MB disk * Serving Ann Arbor since 1988 |

Newsgroup: sci.electronics
document_id: 52731
From: laird@pasture.ecn.purdue.edu (Kyler Laird)
Subject: Re: Telephone on hook/off hok ok circuit

These circuits abound in most electronic project books.  If you're more
inclined to buy something, try Radio Shack.  I think they still have a
device that is designed to disconnect an answering machine when an
extension line is lifted.  It has LED indicators also. 

--kyler

Newsgroup: sci.electronics
document_id: 52732
From: jeh@cmkrnl.com
Subject: Re: Police radar....Just how does it work??

In article <afgE02Wb3dVu01@JUTS.ccc.amdahl.com>,
 dws30@p1ps110cd.amdahl.com (David Sharpe) writes:
> There are a few more details to radar and some
> rumors that are not true.  A common one is that two beams are sent one
> reading the car speed and one the ground speed.  If this were true then
> calabration would be murder.  Hope this helps (Flame On)

Gee, then I guess the extra horn that's mounted in the floor of some SDPD cars,
firing at the ground at a shallow angle, is just for show, huh?

(For calibration, they simply turn off one horn or the other.) 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
document_id: 52733
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Log/stereo high quality pot (hi-fi)

In article <1993Apr5.172839.22714@eng.cam.ac.uk> cmh@eng.cam.ac.uk (C.M. Hicks) writes:
>cobust@seagoon.ee.sun.ac.za (Cobus Theunissen) writes:
>
>>Hi there,
>
>>I am looking for a high quality log/stereo 10k pot for an audio 
>>preamplifier.  The design specifies Alps RKGA-2 10k AX2, but I cannot
>>find it anywhere!  Any suggestions?
>
>The best pots around (IMHO) are made by Penny & Giles in the UK. Their
>basic model has a solid brass case, and conductive plastic elements
>matched to 0.5dB across the whole rotation. The downside is that they
>cost upwards of 50 quid each :-(

The P&G pots are very good.  The Alps ones are usually carried by
the same folks who run the Audio Amateur magazine.  

I'll also recommend the Noble potentiometers, if you don't mind weird
metric sizes on everything.
--scott

Newsgroup: sci.electronics
document_id: 52734
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Police radar....Just how does it work??

In article <1pqb8aINN9vg@hp-col.col.hp.com> cab@col.hp.com (Chris Best)  
writes:
> 
> The manual also got into the "cosine effect", wherein the motorist 
> always gets the benefit of the doubt (effectively).  Depending on
> relative directions of the radar gun and target car, the reading 
> will always be THE SAME AS or LOWER THAN the actual speed of the car.  
> Never higher.
> 
> And always remember that the cop doesn't even need radar to ticket you.
> His (her?) word as a skilled observer is enough. 

The father of a friend of mine is a police officer in West Virginia.  Not  
only is his word as a skilled observer good in court, but his skill as an  
observer has been tested to be more accurate than the radar gun in some  
cases . . ..  No foolin!  He can guess a car's speed to within 2-3mph just  
by watching it blow by - whether he's standing still or moving too!  (Yes,  
I realize that calibrated guns are more accurate than this, but . . .).   
His ability is not that uncommon among people who watch moving things for a  
living, I have heard . . ..

So what good is a radar detector except to give you a split second warning  
that the guy who just cut you off to pass the guy ahead and to your left  
is about to panic stop from 85 on a crowded freeway???

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
document_id: 52735
From: wellison@kuhub.cc.ukans.edu
Subject: Re: Help with ultra-long timing

Thanks for the resposes as they were all good ideas and I am looking at using a
couple of the ideas. I recieved in the mail today the spec sheets on the mil.
spec version of Exar's XR-2240 timer/counter chip. It is stable down to -50 C
and sucks very little power. They show an application for a ultra-long time
delay (up to several years depending on the RC time constant). In this
application, they have two of them cascaded together. The reset and trigger
pins of both chips are tied together and the timebase of the second chip is
disabled. In this configuration, the output is high when the system is reset.
When triggered, the output goes low and stays that way for a total of 65,536 x
the timing cycle of the first chip. The total timing cycle of the two chips can
be programmed from To = 256 x R x C to 65,536 x R x C in 256 steps by selecting
any combination of the counter outputs to the timer output. The beauty of it
is, the timebase chip would only have to have a 100uF timing cap and a 391K
resistor for 39.1 seconds per timing cycle. So I can get a maximum of
2,562,457.6 seconds between timing cycles (39.1 x 65,536 or about 29 days !)
Of course, that's much more than I need (14 days). But the counter allows for
256 binary steps that can be selected for the output for the 'pellet puker'.
After the first 14 days and it trips, it would reset its self for the next 14
day timing cycle and so forth.

Power is still a problem though. A few ideas that you suggested was to bury the
electronics in a hole dug in the snow (as an insulator) and put the pellet
puker up on a tower above the estimated snow fall with a solar panel on it to
keep a charge on a lithium battery pack. I like that idea ;-) This thing has to
work for at least six weeks for three samples and the gas valves are 12 volts
to spit the pellets out onto the snow. Anyway, I ordered the XR-2240's to see
what I can do with them. Should be interesting (as long as I'm not the one that
has to go digging up the pellets in the middle of Antartica freezing my buns
off ;-)

Thanks again everyone...

-=-= Wes =-=-

Newsgroup: sci.electronics
document_id: 52736
From: cph@dmu.ac.uk (Chris Hand)
Subject: Re: PC Based Layout Program

Frank Hielscher (hielsche@aragorn.CSEE.Lehigh.Edu) wrote:
: The PADS*.ZIP files contain subdirectories, and have to be unzipped
: via "pkunzip -d". Then an xcopy /s to three floppies creates the disks
: needed to do the install.

I'm still not sure how this is supposed to work, since the .ZIP files
took up about 2.5Mb, so it must be a tight squeeze on those floppies...

However, I managed to install PADS and I'm pretty impressed.  I created
a couple of schematics without problem, but whenever I try to 
create a PCB layout from one of *my* circuits (rather than the demos)
it doesn't work.  I'm wondering if maybe a file isn't where it should
be...

Can anyone who has a printed manual comment on whether the registration
fee is worth paying?


Chris


-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
document_id: 52737
Subject: Re: Principle_of_the_Breathalyzer
From: srgxnbs@grace.cri.nz

In NZ apparently things like aftershave are also giving positive
readings


Newsgroup: sci.electronics
document_id: 52738
From: rainer@spot.Colorado.EDU (Rainer Malzbender)
Subject: Re: HC11 blues -> no can find

In article <pat.734048757@fegmania.wustl.edu> pat@fegmania (Patrick Niemeyer) writes:
>I too had trouble finding hc11's when I looked for them a while back.
>I'd be interesting in hearing if anyone knows about their availability now...

The newest JDR Microdevices catalog has at least one variant of the HC11.

-- 
Rainer M. Malzbender
Fyzzicks, CU Boulder
(303)492-1366             

Newsgroup: sci.electronics
document_id: 52739
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Oscilloscope triggering

In article <1993Apr5.120921.28985@dxcern.cern.ch>, jeroen@dxcern.cern.ch (Jeroen Belleman) writes:
|> In article <C4vs0G.5ux@murdoch.acc.Virginia.EDU> dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
|> >	Is it just me, or does anybody else out there NOT like digital
|> >scopes. My school has ...
|> >
|> >					David Jacobowitz
|> >					dgj2y@virginia.edu
|> 
|> Oh no you're not the only one. Analogue scopes give you (or me, at
|> least) a fair idea of what's going on in a circuit. Digital scopes
|> seem to have a habit of inventing a sizable part of it. E.g. even
|> when there are only a few samples per period, our HP54510A displays a
|> continuous waveform, complete with non-existing overshoots. I've
|> waded through lots of manual pages and menus, but I haven't found yet
|> how to turn this off. It doesn't show which points have actually
|> been measured, as opposed to those which have been interpolated,
|> either.

Perhaps you're using the wrong brand! (Sorry all HP fans, but I have
a hard time being convinced that their scopes match the rest of their
(excellent) gear).

One of the principal functions I look for when considering a DSO is
whether you can turn interpolation off. The other important feature
is to disable repetitive waveform acquisition i.e. being able to lock
the instrument into real time capture mode.

|> 
|> Secondly, I don't like menus. I want to see all common functions
|> with their own button. (You'll have guessed I love analogue Tek
|> scopes) I'd choose a knob with printed legend over an on-screen
|> display with up-down buttons right away. The single knob of most
|> digital instruments never seems to be connected to the right function
|> at the right moment.
|> 

I agree with you here. The only consolation is that manufacturers are
_beginning_ to pay attention to ergonomics when designing the menus.
However, to be fair, it seems that first time scope users (our students)
seem to adjust to menus easier than navigating around the twenty or
more knobs required of a "real" scope :-)

|> Last but not least, you never know if the waveform displayed is old
|> or recent, noisy or just incoherently modulated, heck, you don't
|> even know if it really looks the way it's displayed. Digital scopes
|> only show you a tiny fraction of what's going on. Most of the time
|> the're busy computing things.

This is one area that newer DSOs are addressing. I recently evaluated
the latest box from Tek - their TDS320 - which seems to be a worthy
alternative to a standard 100MHz analogue CRO. This instrument has
a 100MHz, 500Ms/s spec, meaning that it is _always_ in real time
capture mode. The pricing also matches equivalent analogue scopes in
the range. The downer is that the instrument uses menus again, but at
least they appear to be logically laid out.
|> 
|> There are only three situations for which I would prefer a digital
|> scope: Looking at what happened before the trigger, looking at rare
|> events, and acquiring the data to have my computer play with it.
|> 
|> 
|> Let's hope scope manufacturers are listening...
|> 
|> Best regards,
|> Jeroen Belleman
|> jeroen@dxcern.cern.ch

One more thing about the new, "simpler", front panels. These instruments
tend to use digital rotary encoders as knobs now. This is a vast improvement
over the old oak switch. The single most common cause of failure in our
scopes (other than students blowing up inputs!) is mechanical wear on these
switches. I look at the new panels as a great step toward increasing the
longevity of the instruments.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 52740
From: rob@dexter.psych.umn.edu (Robert Stephens)
Subject: Compressor Problem

I have a stereo compressor-limiter by 
Audio Logic (Model MT-66).  The gates work,
but the compressor seems to be gone on one
channel, and very weak on the other.  

I'll probably need an ocsilloscope to trace it
down (no pun intended), but if any one with
experience with this type of equipment could
point me in a certain direction as to where the 
circuit is most likely to fail, I'd sure appreciate it.


-- 
Robert C. Stephens		rob@dexter.psych.umn.edu		

Human Factors Research Lab
University of Minnesota


Newsgroup: sci.electronics
document_id: 52742
From: neale@ee.rochester.edu (Reg Neale)
Subject: Pioneer Laser player

I'm trying to figure out how to operate a Pioneer Laserdisc LD-1000 that I bought at a surplus store. It is reputedly from some kind of computerised viewing
and/or ordering system. THere is what may be an HPIB connector on the back. When
I power it up, the front panel power light comes on, but no activity, and the
door doesn't open. Anyone have any experience with this unit or any ideas on how
to obtain documentation?

Newsgroup: sci.electronics
document_id: 52743
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help with ultra-long timing

In article <1993Apr5.083324.48826@kuhub.cc.ukans.edu>, wellison@kuhub.cc.ukans.edu writes:
|> I have a project that was drooped in my lap that is somewhat a pain to design.
|> What I am looking for is a stable ultra-long solid state timer. What they want
|> to do is to place this thing on the Antartic ice shelf and measure the amount
|> of snow fall over a period of six weeks. Every two weeks, they want to trip a
|> selonoid to discharge different colored pellets by gas pressure out across the
|> snow. Then by digging down into the snow, the snow fall amount can be measured
|> as they come to the different color pellets.
|> 
|> The problem is trying to build a timer that would stand the cold (-40 degrees)
|> and a power source that wouldn't drain. I have looked at the XR-2204 timers and
|> the standard NE556 dual timers, but thier temp specs won't go that low. Also,
|> two weeks equates to 1,209,600 seconds per firing, which means one big timing
|> cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
|> 5 volts and are small in size. But again, the time of discharge at -40 or lower
|> degrees isn't linear. I was thinking of using several timers chained together 
|> to fire the selonid at the end of the timing period, but that blasted cold and
|> the drain on a battery over six weeks is the pain. One possibility would be to
|> use solar panels, but this is during the six month twilight. Anyone have any
|> good ideas ?
|> 
|> Thanks in advance...
|> 
|> -=-= Wes =-=-

Firstly, I would never consider trying to make a one-shot timer. Your 2F2 cap
will have been designed as a RAM battery substitute, rather than for use in
applications where you wish to drain the cap with a constant current. Their
performance, in some respects, is more akin to batteries than to a normal cap.
The other point is that big electro's are usually rated with -5%+20% tolerances,
so calculating exactly what capacitance you have (particularly when considering
the cold).

You should be looking at designing a micropower oscillator and divider chain,
that "rolls over" (from zero to maximum count, or vice-versa) once every
1,209,600 seconds. If you were to use something like a 110Hz clock, you would
need a divider chain of 2^27, to give an error of less than one percent in the
firing times over the six week period. Of course, you could trim the 110Hz
oscillator to give you exact time, but the likelyhood of the oscillator
remaining exactly constant at -40 is low anyway.

I would suspect that there would be far more battrey drain in firing the
solenoid than there would be in the timer circuit.

Caveat - I'm not experienced in low temperature electronics, so I can't
guarantee that this (or any other) approach is the best for inhospitable
conditions.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 52744
From: engp2254@nusunix1.nus.sg (SOH KAM YUNG)
Subject: Re: Protection of serial (RS232) lines

Martin John Gregory (mgregory@flash.pax.tpa.com.au) wrote:
: I've started to look at some devices doing serial data transmission
: over fairly decent distances in fairly noisy environments, and have
: seen a variety of schemes for protecting the RS232 transceivers (and
: the rest of the circuit) from transients on the serial lines.  I'm
: left wondering what is the best way of doing this?  How necessary is
: it?
: [stuff deleted]
: What is the wisdom on this out there?
: 
: Ta,
: 
: Martin.
: 
: 
From what I know, protection is necessary, esp. if you plan to route
the cables into an unknown environment (out of your control). Things
like accidental shorts between the signal lines and power cables, or
even lightning strikes are very likely and I don't think you like to see
the sight of your computer going up in smoke! [Even ethernet cards are
protected. I've looked at the one in my PC and the connector is
protected by a gas discharge tube!]

{But if you plan to use the serial cables for internal routings (i.e. in
controlled environments), it should be reasonably safe not to have
them.}

Suggestion: look in the RS data book. They have several RS232
transceivers that have overvoltage protection. Among them include the
LT1080, LT1081 and MAX250 and MAX251. The Maxims are suppose to be
electrically isolated ones but still need opto-isolators to work (don't
ask me why. I've never used them before.

Another alternative is an RS232 surge protector. Two are listed in the
RS catalogue. If you need additional info (i.e. stock nos.), just e-mail
me.

Soh Kam Yung,
engp2254@nusunix1.nus.sg

Newsgroup: sci.electronics
document_id: 52745
From: john@gu.uwa.edu.au (John West)
Subject: Re: Protection of serial (RS232) lines

laird@stable.ecn.purdue.edu (Kyler Laird) writes:

>There is at least one optically-isolated RS-232 transceiver chip.  I
>don't remember where I saw it.

RS Components (they exist in Australia and the UK. Don't know about the US) have
little chips called Isolated MAX 250 and 251. They give you isolated RS-232 from
a single 5V supply. External components are 4 caps, 4 optoisolators, a diode,
and an isloting transformer. They go up to 19.2K baud..

John West
--
For the humour impaired: Insert a :-) after every third word

Newsgroup: sci.electronics
document_id: 52746
From: rkim@mars.uucp (Richard H.S. Kim)
Subject: Need sources for HV capacitors.

Recently, my video monitor went dead, no picture, some low distorted sound.
I didn't hear the tell-tale cracking that indicated HV at work, nor are the
filaments at the far end of the tube glowing orange, just nothing.

On examining the power board, I noticed the largest capacitor with a very
bad bulge at the top.  Naturally, I want to replace it, but I can't find
any sources.

The electrolytic capacitor is 330 mF at 250WV.  It has radial leads, and is
roughly 1 1/2 inches long, 1 1/8" wide.  The dimensions are important since
the whole board fits in a metal cage, leaving little room.

Living in the Los Angeles area, I've been to numerous stores (Dow Radio,
All Electronics, ITC Elect, Sandy's, Yale Elect) with empty hands.

Can anyone suggest sources for high-voltage capacitors?  Mail order is 
fine, although I'd rather check out a store to compare the can.  I'm going
to try a video electronics store, hopefully they'll have HV caps.

(By the way, the monitor is a ATARI SC1224, Goldstar circuitry, Masushita
tube.  Anyone else had problems?)

Thanks in advance,
Rich K.

email>  rkim@opus.calstatela.edu

Newsgroup: sci.electronics
document_id: 52747
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help with ultra-long timing

In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
|> (1) Don't use big capacitors.  They are unreliable for timing due to
|> leakage. 
|> 
|> Instead, use a quartz crystal and divide its frequency by 2 40 times
|> or something like that.
|> 
|> 1 MHz divided by 2^40 = 1 cycle per 2 weeks, approximately.
|> 
|> (2) I wouldn't expect any components (other than batteries or electrolytic
|> capacitors) to fail at -40 C (or -40 F for that matter either :) ).
|> The battery is going to be your big problem.  Also, of course, your
|> circuit shouldn't depend on exact values of resistors (which a crystal-
|> controlled timer won't).
|> 

... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
mechanically resonating device, extreme cold is likely to affect the
compliance (?terminology?) of the quartz, and hence its resonant frequency.

|> -- 
|> :-  Michael A. Covington         internet mcovingt@ai.uga.edu :    *****
|> :-  Artificial Intelligence Programs       phone 706 542-0358 :  *********
|> :-  The University of Georgia                fax 706 542-0349 :   *  *  *
|> :-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **


JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 52748
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: HC11 blues -> no can find

In article <pat.734048757@fegmania.wustl.edu>, pat@fegmania (Patrick Niemeyer) writes:
|> ree88132@zach.fit.edu (Keith Ledig) writes:
|> 
|> >was told by other people that it just takes a long time.  I heard
|> >rumors that the HC11 is very hard to get these days and is being
|> >replaced by the 711 series.  The sales person is trying to push
|> >the 711.  Can someone please tell me what is going on with these
|> >microcontrollers.  I can't seem to get a straight answer.
|> 
|> I too had trouble finding hc11's when I looked for them a while back.
|> I'd be interesting in hearing if anyone knows about their availability now...
|> 
|> Thanks,
|> Pat


The HC711 is an EPROM version of the HC11. Raw HC11 parts have factory set
ROM images, and as such are useless to the hobbyist. HC811 parts have
EEPROM, allowing for electrical erasure and reprogramming.

Some Motorola parts (such as the HC705K1) have EPROM, making them user
programmable, but come with options of either windowed or sealed. The
more expensive windowed packages allow multiple use, the plastic dip
varieties are one-time programmable, since there is no way of exposing
the EPROM array to light.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 52749
From: tg@cs.toronto.edu (Tom Glinos)
Subject: 12V to 3V and 48V at 3A

The subject line says it all. I'm working on a project
that will use a car battery. I need to pull off 3V and possibly
48V at 3A.

I have several ideas, but I'd prefer to benefit from all you
brilliant people :-)
-- 
=================
"Conquest is easy, control is not"	| Tom Glinos @ U of Toronto Statistics
[Star Trek TOS]   			| tg@utstat.toronto.edu
USL forgot this simple history lesson

Newsgroup: sci.electronics
document_id: 52750
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: Help with ultra-long timing

Sounds like a job for a universal time reciever.  I don't know the
logisitics of the situation, but if you could just place a reciever in
snow and place the oscillator in a nice lab somewhere else, your
problems should be solved.
Just a suggestion.

Wayne Martin

Newsgroup: sci.electronics
document_id: 52751
From: kthompso@donald.WichitaKS.NCR.COM (Ken Thompson)
Subject: Re: 68HC11 problem

mdanjou@gel.ulaval.ca (Martin D'Anjou) writes:
B
)>>>>>>>>> Votre host est mal configure... <<<<<<<<<<<<


)Bonjour Sylvain,
)	J'ai travaille avec le hc11 il y a 3 ans et je ne me souviens pas de toutes les possibilites mais je vais quand meme essayer de t'aider.

)	Je ne crois pas que downloader une programme directement dans le eeprom soit une bonne idee (le eeprom a une duree de vie limitee a 10 000 cycles il me semble). Le communication break down vient peut-etre du fait que le eeprom est long a programmer (1ms par 8 bytes mais c'est a verifier) et que les delais de transfer de programme s19 vers la memoire sont excedes. Normalement, les transferts en RAM du code s19 est plus rapide car le RAM est plus rapide que le eeprom en ecriture.

)	C'est tout ce que ma memoire me permet de me souvenir!

)Bonne chance,

Oh yeah easy for him to say!...

-- 
Ken Thompson    N0ITL  
NCR Corp.  Peripheral Products Division   Disk Array Development
3718 N. Rock Road  Wichita KS 67226   (316)636-8783
Ken.Thompson@wichitaks.ncr.com 

Newsgroup: sci.electronics
document_id: 52752
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Wire wrap questions (again?)

In article <PASCAL.93Apr1160623@ap10.apd.cpg.sony.co.jp> pascal@apd.cpg.sony.co.jp (Pascal Goguey) writes:
>In article <7376@blue.cis.pitt.edu> macfitz+@pitt.edu (Mark D Fitzsimmos) writes:

> *After a considerable amount of research, review of discussions 
> *on this group, and mainly fruitless time on breadboards, I have 
> *decided that the path of least resistance for prototyping my (not 
> *necessarily someone else's) electronic designs is wire wrapping.  

>	I have no idea about what you want to do, but be careful :
>Wire wrapping increases a lot the wiring capacitance. That shouldn't
>be a problem for "slow" applications (i.e a few MHz), but as for
>quicker ones (around 30 / 40 MHz), I doubt that it can work.


	Fortunately, wire-wrapping is a better wiring technique than
most at high frequencies; Cray computers (up to the X-MP, at least)
all had wirewrapped backplanes.  Wirewrap gets into trouble at
much higher frequencies than any TTL can handle.  The 'increase'
of wiring capacitance is not really relevant (you have to use
transmission line techniques, and the capacitance is no problem).

> *1) Where can I get a decent wrapping tool?  I'd like to spend less 
> *than $150 for an AC powered unit including bit and sleeve.

>	Hand powered is the best. There are good AC powered ones,
>but rather expensive. A low-cost one doesn't work very well.

	Hand-powered is a terrible choice (IMHO) unless you are
a field maintenance person who will do maybe a dozen connections
at a time.  Your hands will cramp.  Battery-powered wire-wrap guns
are available in the $150 range, and so are the little
twiddle-stick manual types ($15).  For a modest project, of
a couple hundred connections, I'd prefer to borrow a professional
AC unit... or a pneumatic one.

	John Whitmore

Newsgroup: sci.electronics
document_id: 52753
From: jkeais@ucssun1.sdsu.edu (keais j)
Subject: Re: Pioneer Laser player

In article <1993Apr6.005150.10250@ee.rochester.edu> neale@ee.rochester.edu (Reg Neale) writes:
>I'm trying to figure out how to operate a Pioneer Laserdisc LD-1000 that I bought at a surplus store. It is reputedly from some kind of computerised viewing
>and/or ordering system. THere is what may be an HPIB connector on the back. When
>I power it up, the front panel power light comes on, but no activity, and the
>door doesn't open. Anyone have any experience with this unit or any ideas on how
>to obtain documentation?

What you have is one of the LD players from a video game (Dragon's Lair,
Space Ace, etc). Call Pioneer Technicial Support 213-498-0300 (at least
that's the number I called them at) and ask for the LD-V1000 Interface
Guide. It shows how the parallel interface should be wired and the codes
for the commands (play, pause, reject, etc). The guide is mainly for hooking
the player to a computer, but with a little work, you could build a wired
controller.


Jim Keais        jkeais@ucssun1.sdsu.edu

Newsgroup: sci.electronics
document_id: 52754
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Help with ultra-long timing

In article <1pqu12$pmu@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>|> (1) Don't use big capacitors.  They are unreliable for timing due to
>|> leakage. 

	True (especially for electrolytic capacitors at high temperature).

>|> Instead, use a quartz crystal and divide its frequency by 2 40 times
>|> or something like that.

>... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
>mechanically resonating device, extreme cold is likely to affect the
>compliance (?terminology?) of the quartz, and hence its resonant frequency.

	Low power quartz oscillators are usually 32 kHz (and THESE
have significant temperature drifts, which one doesn't often notice
while wearing the watch on one's wrist).  Low temperature sensitivity
is available in other crystal types, which unfortunately
are larger and higher frequency (1 MHz or so) and take more
battery power.  

	Programmable timers might be less accurate, but they
are more power-stingy than suitable crystal oscillators.

	John Whitmore

Newsgroup: sci.electronics
document_id: 52755
From: wa2ise@cbnewsb.cb.att.com (robert.f.casey)
Subject: 2 level brightness Xmas light set (for Easter?


Yes, I know it's nowhere near Christmas time, but I'm gonna loose
Net access in a few days (maybe a week or 2 if I'm lucky), and wanted
to post this for interested people to save 'till Xmas.   :-(
Note: Bell Labs is a good place IF you have a PhD and a good boss, I
have neither.
--------------------------------------------------------------------------

Subject: Xmas light set with 2 levels of brightness

Another version of a variable brightness Xmas light set:
This set starts with a 2 blinker 35 bulb string.  

DIAGRAM:  orginal 2 way set

120v---+--b-*-*-*-*-*-*-*--!
       !---b-*-*-*-*-*-*-*-!
                           !
120rtn_____________________!

modified set for 2 level brightness:

                string 1
120v---------*-*-*-*-*-*-*-*--!
  \_10K_______*-*-*-*-*-*-*-*-!
    5w    !      string 2     !
          b   ________________!
120v rtn__!___!

             ^ Note: no mods to wiring to the right of this point.

Only one blinker is used.

Note that the blinker would not have as much current thru it as the
string 1 bulbs, because of the second string of bulbs in
parallel with it.  That's why the use of the 10K 5W resistor
here to add extra current thru the blinker to make up for the
current shunted thru the second string while the blinker is glowing
and the second string is not glowing.  When the blinker goes open,
this resistor has only a slight effect on the brightness of the
strings, s1 slightly dimmer, s2 slightly brighter.  
Or use a 3W 120v bulb in place of the 10K resistor if you can get
one.  Caution, do not replace with a standard C9 bulb, as these
draw too much current and burn out the blinker.  C9 = approx 7W.

What you'll see when it's working:  powerup, string 1 will light 
at full brightness, and b will be lit, bypassing most of the current 
from the second string, making them not light.  b will open, placing 
both strings in series, making the string that was out to glow at a 
low brightness, and the other string that was on before to glow 
at reduced brightness. 

Be sure to wire and insulate the splices, resistor leads, and cut wires 
in a safe manner!

Newsgroup: sci.electronics
document_id: 52756
From: blakey@ug.cs.dal.ca (Jason Blakey)
Subject: FTP sites anyone?

    Hello netters:)  Does anyone out there know any FTP sites for projects,
plans, etc of an electrical nature?  

-Jason
-- 
 ............................................................................ 
                      Jason Blakey -> blakey@ug.cs.dal.ca 

Newsgroup: sci.electronics
document_id: 52757
From: davidb@macadam.mpce.mq.edu.au (David Bull)
Subject: Intel RMX O/S Documentation Wanted


We've just been donated a large machine for use in our
robotics lab. This device is complete with a 286 based
controller, running the Intel RMX operating system.

Unfortunately, we don't have any documentation on RMX.

Can anybody out there in netland help?

Please reply via email; I don't regularly catch up with
the news.

Thanks,

David Bull

davidb@mpce.mq.edu.au



Newsgroup: sci.electronics
document_id: 52758
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: What is Zero dB????

In article <sehari.733764410@vincent1.iastate.edu>, sehari@iastate.edu (Babak Sehari) writes:
|> In <C4truE.6AA@ms.uky.edu> msunde01@mik.uky.edu (Mark  Underwood) writes:
|> 
|> >I am somewhat familiar with the dB measurements as they apply to  
|> >electrical circuits - i.e. it is the gain of (for example) an amplifier  
|> >measured on a logarithmic scale.  However, this requires that you have a  
|> >reference value:  i.e the ouput is +20dB (e.g.) with respect to the input  
|> >signal.

<stuff deleted>

|> What you actually talking about here is dBm and not dB.  However, the terms
|> are used loosely by most people.  ``dBm'' is power with respact to 1mW, whereas
|> dB is a ratio.  Now, like these two English statement:
|>
|> 1.  I am doing well.
|> 2.  I am doing good.
|> 
|> Similarly, people usually use dB for dBm. Another common mistake is spelling
|> ``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
|> ``Bell'' company, the mother of AT&T and should be capitalized.
|> 
|>                           With highest regards,
|>                                Babak   Sehari.

Good gravy! Decibels are all *ratios.* The question that remains in
any ratio is the reference unit used. Sometimes, this will be a reference
power, such as 1 milliwatt (given a certain circuit impedance which
should also be included in the fine print or known, like 50 ohms
in an RF circuit of that impedance), leading to an accepted
notation of dBm. Maybe it might be dBV, disregarding the impedance of
the circuit and power developed, using 1 volt as reference *amplitude*
(rather than reference power). Or, it might have an arbitrary or omitted
reference that is not included in the notation, leading to just plain dB.
So. look at it this way--'dB' has an implied reference while notation
such as 'dBm' has an explicit reference.

For power:

  dB = 10*log( P(measured)/P(reference) )

For amplitude

  dB = 20*log( A(measured)/A(reference) )

'B' is for bel, which is a standard term for a log ratio to the base
10, named after Alexander Graham Bell. A 'deci' Bel is 1/10 of a bel.
It has nothing to do with the Bell Telephone company except for
the common founder's name. The small 'd'/large 'B' is per SI notation
convention. I don't know anyone that's been crucified for messing it up.

Common references for audio are:

	0 dBm = 1 milliwatt across 600 ohms
	0 dBV = 1 volt

	0 VU (a zero on the VU meter) = +4 dBm  (pro gear line level)
	0 VU = -10dBV	(consumer gear line level)


Often times, a power amp VU meter will be aligned using
the rated power of the amp as the 0 dB point. It is all
done to whatever reference is reasonable for the application
or moment.

Note that in a circuit with a given (and maybe unknown) linear
impedance, if the amplitude goes up so many decibels, the
power will also increase the same amount. This proof can be done
with the above two identities and ohm's law.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52759
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Flyback squeal in video monitors

In article <1993Mar31.204036.4359@ssc.com>, markz@ssc.com (Mark Zenier) writes:
|> Zack Lau (zlau@arrl.org) wrote:
|> : In sci.electronics, xhan@uceng.uc.edu (Xiaoping Han) writes:
|> : >In article <1993Mar24.163510.158@hubcap.clemson.edu> michaet@hubcap.clemson.edu (Michael D. Townsend) writes:
|> : >>brendan@macadam.mpce.mq.edu.au (Brendan Jones) writes:
|> : >>
|> : >>My mom's 25" Magnavox does this as well.  I put chewing gum all around
|> : >>the horizontal sync transformer so it wouldn't resonate the board as
|> : >>much.  Don't flame, it worked.  I realize that there is a more suitable
|> : >>substance available for this purpose, but I don't remember what and
|> : >>where it is.
|> : 
|> : >Adhesive silicon, from hardware store.
|> : 
|> : If it smells like vinegar, it may damage metal surfaces by
|> : promoting corrosion.  
|> 
|> Anybody tried Superglue (cyanoacrylate ?).  This should sneak
|> into the cracks better, and is stiffer than silicone.  

I've found this works pretty well on noisy laminated power
transformer cores and windings (the 60Hz kind). Likewise, if
anybody has tried this on a flyback I'd like to hear about it.

I would suspect it would not be as effective as it was on power
transformers as the material wouldn't damp as well--something
I suspect would be critical at the frequencies involved (in other
words, you want absorption rather than prevention which would be
real difficult at 15 KHz).

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52760
From: ph@gmd.de (Peter Hendricks)
Subject: Re: Wanted: A to D hardware for a PC

In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:

>	If you know much about PC's (IBM comp) you might try the joystick
>port.  Though I haven't tried this myself, I've been told that the port
>has built in A-D converters.  This would allow the joystick to be a couple of 
>pots.  If you could find the specs this might just work for you...

I guess 100k, connecting pins 1-3 (1x), 1-6 (1y), 9-11 (2x), and 9-13 (2y).

Or: Get an 8-bit DA-Converter (merely a couple of transistors and
Resistors) and an OpAmp to compare its output to the voltage you want to
measure, connect them to a spared printer port (if you have one), and do
the rest by software (stepwise refinement). The port addresses for your
printer ports are probably: &H378 (LPT1), &H278 (LPT2). This should work
well enough for your purposes.

Hope this helps

--
GMD,  Schloss Birlinghoven,  Postfach 1316,  D-5205 St. Augustin 1,  FRG

e-mail:  Peter.Hendricks@gmd.de			ph@zi.gmd.dbp.de
	 ph@gmd.de

Newsgroup: sci.electronics
document_id: 52761
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Wanted: A to D hardware for a PC

>In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:
>
>>	If you know much about PC's (IBM comp) you might try the joystick
>>port.  Though I haven't tried this myself, I've been told that the port
>>has built in A-D converters.  This would allow the joystick to be a couple of 
>>pots.  If you could find the specs this might just work for you...

I believe that the "A-D converters" found on a joystick port are really
timers that tick off how long it takes an R-C circuit (the R being your
paddle) to charge up to something like 1/2 Vcc.  For games this works
pretty well, but you certainly wouldn't want to try to take lab
measurements off something as non-linear as that.

Hmm... I suppose you could linearize it in software, but the real problem
is that the precision of your measurement is no longer constant (higher
voltages would be more precise).

On the other hand, I could be wrong and perhaps the game card designers
splurged for the extra $.50 to make a cheap constant current source out of
an op amp.  But I wouldn't expect that...

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 52762
From: rooi@duteca3.et.tudelft.nl (Mark de Rooi)
Subject: Calculating a transformer - help needed

I want to convert a 500 Volt sinewave with frequency between 1 kHz
and 10 kHz, to a 10 Volt sinewave with the same frequency, by
means of a transformer. The secondary current will be .6 A (600 mA).

What kind of transformer should I use (ferrite?)
Can I buy one? If so, I need a partnumber and supplier
If I cannot buy one, how do I go about winding one myself?
What core do I use, how big must it be in order not to saturate,
what thickness copper wire, how many turns, etc.?

I know little about analog electronics, so I hope some kind
soul here will help me out.
Pointers to relevant databooks will also be highly appreciated.

Thanks,

Mark de Rooi
rooi@tpd.tno.nl

Newsgroup: sci.electronics
document_id: 52763
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: HV diodes

In article <7480220@hpfcso.FC.HP.COM>, myers@hpfcso.FC.HP.COM (Bob Myers) writes:
|> > Nope.  The dag is on the outside of the tube, and is grounded.  The inside
|> > aluminization *is* the second anode, and is connected to the 'anode'
|> > suction cup.  This (with the glass of the tube in between) is a capacitor,
|> > and is used as the power supply bypass/filter for the HV supply.  Some
|> > smaller scope tubes don't have an aquadag coating on the outside.  If they
|> > are in mu-metal shields, you still have a capacitor.
|> 
|> Actually (and I think I said this in the original, but perhaps wasn't clear
|> enough) there is usually both an internal AND an external dag.  Of the two,
|> the internal dag is the more important; the aluminization of the back of the
|> phosphor is in most cases not adequate to guarantee connection to the anode
|> "button" (and in the case where the gun assembly includes an accelerating
|> electrode at anode potential, most definitely does not provide THAT 
|> connection).

Bob is indeed correct here in more than one way. A look in the old
RCA picture tube manual backs this up, as does SAMS Reference Data
handbook. The internal coating around the perimeter of the CRT
(not the aluminum or tin CRT face coating) is referred to as a
"dag" as well as the outer coating.

Thankfully, I didn't need to go to a f****** library to find it, either.
One sparkling water for Mr. Vanderbyl (no caffeine in that, is there).

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52764
From: dhembrow@eoe.co.uk (David Hembrow)
Subject: Re: SID chip to IBM system bus

Mr MC Howell (g90h6721@hippo.ru.ac.za) wrote:
: Please don't ask questions like "why don't you buy a soundblaster".  The
: answer is simple "Overpriced considering the sound quality".

Why not try one of the projects to build a DAC connected to the parallel
port as documented in some files which come with modplay ? These vary from
a 4 DAC design to a simple single DAC made only of resistors.-- 
David Hembrow                   EO Europe Ltd.,
email:  dhembrow@eoe.co.uk      Abberley House, Granhams Road,
                                Great Shelford, Cambridge CB2 5LQ, England

Newsgroup: sci.electronics
document_id: 52765
From: leapman@austin.ibm.com
Subject: HeathKit/Zenith


Does anyone out there have the toll-free (catalog request and order line) for
Heathkit/Zenith?  Please post the number if you've got it!  Thanks.

Newsgroup: sci.electronics
document_id: 52766
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Info on NEC 3D Multisync monitor

myers@hpfcso.FC.HP.COM (Bob Myers) writes:

> > I am looking for any info I can get on the NEC 3D monitor.
> > I know that it is a multisync but that is about all.
> > I plan on buying one second-hand in a while depending on its specs.
> > 
> > Does anyone know the min/max frequencies, whether it is interlaced, 
> > non-interlaced, or both, video compatability, etc?
> > I have seen a reference to it being .28 pitch with 1024 X 720 resolution 
> > and that it supports SVGA from one source and that it doesn't support 
> > SVGA from another source.  (Neither source seemed to have much reliable 
> > info so I don't want to take a guess.)
> 
> I'm at home right now, and so am away from my monitor files; the following
> is off the top of my head, subject to revision, worth-what-ya-pay-for-it
> sort of info.  If you don't hear from anyone who has spec sheet in hand,
> e-mail me and I'll look it up.
> 
> If I'm remembering correctly, the 3D is a 14" 0.28 mm pitch multisync that
> covers at least VGA (31.5 kHz horizontal, 60 Hz vertical) to 1024 x 768 
> 60 Hz (which is going to be about 48 kHz horizontal).  It may go somewhat
> higher than that on the horizontal, but you won't be happy with anything
> beyond 1024 x 768 on a 14" 0.28 tube; you probably won't be too thrilled
> with the 1024 x 768 on this tube, but it *will* sync up and display it.
> (I prefer at least a 16" 0.28 for this resolution.)  Since SVGA is 800x600,
> it'll do that too.  The horizontal range probably goes lower than 31.5, but
> I don't know if it goes all the way down to straight NTSC-rate TV (which need
> about 15.75 kHz sweep).  As far as "video compatibility" (if I'm reading
> the question right: it won't take anything but analog RGB inputs.  In other
> words, it has no way to decode NTSC or Y/C video inputs.  You would need
> some sort of board to to this conversion - like the sorts of things that 
> let you display NTSC on a VGA display.
> 
> Hopefully, now, I'll see this response of mine, and it'll remind me to
> look this stuff up and confirm it.  (Or force me to post a hasty retraction!)

Ok, I was under the impression that it accepted digital input.

I still don't know for sure if it accepts BOTH interlaced and 
non-interlaced as I have gotten conflicting info.

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 52767
From: cobust@seagoon.ee.sun.ac.za (Cobus Theunissen)
Subject: Wide band Analog time delay

Hi there,

I am looking for a wide band analog time delay (not phase delay)
variable from 200 microseconds to 2 milliseconds.

Please reply via email to rrc@firga.sun.ac.za

Newsgroup: sci.electronics
document_id: 52768
From: jmichael@vnet.IBM.COM
Subject: Re: A to D hardware for a PC

If you can find a copy of "8088 Assembler Language Programming: The IBM PC"
by Willen and Krantz, 2nd ed. pub. by Sams, there is a discussion of the
game control adapter, monostable multivibrators, and conversion to other
uses, as well as an assembler program. If you need greater accuracy, there
is no reason you couldn't modify the approach to suit your needs.

Jim

Newsgroup: sci.electronics
document_id: 52769
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Re: Homebuilt PAL (EPLD) programer?

In sci.electronics timd@fenian.dell.com writes:

>Anyone know a reasonable circuit for programming PALs?  I am interested
>in programming a wide range of EPLDs but would be happy with something 
>that could handle a 22V10 or thereabouts.

I too would be interested in ANY information on the subject of programing
PALS etc.....

  Better to know what your on about before you start something, I always
say. Often saves you a packet as well !!

Thanks in advance..

Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv     |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the Sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
document_id: 52770
From: hanavin@huey.udel.edu (Chuck Hanavin)
Subject: Re: HeathKit/Zenith

In article <C52EGz.27t3@austin.ibm.com> $LOGIN@austin.ibm.com writes:
>
>Does anyone out there have the toll-free (catalog request and order line) for
>Heathkit/Zenith?  Please post the number if you've got it!  Thanks.

----------------------------------------------------
1-800-253-0570

Newsgroup: sci.electronics
document_id: 52771
From: long@spk.hp.com (Jerry Long)
Subject: Re: Principle_of_the_Breathalyzer

william burchill (williamb@ee.ubc.ca) wrote:
: 	Does anybody out there know how the hand held breathalyzer used
: by our police works?  I would like to hear about this and the more
: general problem of detecting smells by machine.
: 
: Thanks, William.
: 
: williamb@ee.ubc.ca
: 

From what I have read about these little gadgets, it works on
a electrochemical galvanic principle. The sensing unit has a
chemical matrix which produces an electrical voltage proportional
to the amount of chemical compound it is designed for ... in this case
I believe it is the Hydroxyl group???  

I have also heard -  not tested :-)  - since common gasoline is also
a member of this Hydroxyl group, it will also cause a failing breathalizer
failure! Next time you get stopped for DUI, say you just siphoned gas from
your neighbors car (you know..... the Oklahoma credit card) and chances
are you won't get a DUI ticket!!!!


 
Jerry Long

long@spk.hp.com
****************************************
Disclaimer.... Opinions are my own and
do NOT reflect those of my employer.  
**************************************** 

Newsgroup: sci.electronics
document_id: 52772
From: kenh@sail.LABS.TEK.COM (Ken Hillen)
Subject: RF data transmission

I need a off-the-shelf method of transmitting small amounts of data up to
300 feet.  The data is low speed and can be encoded as needed.  Low power
on the transmitting end would be a plus.  An FCC certified product would
be prefered.

If you have any pointers to products or companies I'd appreciate hearing from
you.

Thanks,
Ken

Newsgroup: sci.electronics
document_id: 52773
From: massey@travis.llnl.gov
Subject: Re: Jacob's Ladder

In article <C4z6x7.16B@murdoch.acc.Virginia.EDU>, dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
> 	I've been wanting to build a Tesla coil for quite awhile now (
> who doesn't, right? ) and I thought it would be a good intermidiate
> step to build a JAcob's Ladder first.
> 	Well, I have been looking for a high voltage transformer that
> is reasonable inexpensive ( neon sign transformers cost mucho ).


In the past I've managed to buy used neon sign transformers from sign shops 
for about $20. Try calling around.


Warren N. Massey                                      Massey@Travis.LLNL.Gov
Lawrence Livermore National Laboratory   7000 East Ave., P.O. Box 808, L-495
Livermore, Calif. 94550  <<<My opinions are mine alone>>>      (510)422-1958

Newsgroup: sci.electronics
document_id: 52774
From: pw@panix.com (Paul Wallich)
Subject: Re: Help with ultra-long timing

In <1pqu12$pmu@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>|> Instead, use a quartz crystal and divide its frequency by 2 40 times
>|> or something like that.
>... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
>mechanically resonating device, extreme cold is likely to affect the
>compliance (?terminology?) of the quartz, and hence its resonant frequency.
 
Yes, but in a fairly reproducible way. -40 is only a smidgen of the
distance to absolute zero. And in any case you're going to have to
borrow freezer space from a bio lab or someone to test/calibrate this
darling anyway. Btw, you're probably going to want those big capacitors
you found to fire the solenoid -- High current drain on frozen batteries
can be an ugly thing.

paul

Newsgroup: sci.electronics
document_id: 52775
From: moffatt@bnr.ca (John Thomson)
Subject: Re: What is Zero dB????

Joseph Chiu (josephc@cco.caltech.edu) wrote:
: sehari@iastate.edu (Babak Sehari) writes:
: 
: >Similarly, people usually use dB for dBm. Another common mistake is spelling
: >``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
: >``Bell'' company, the mother of AT&T and should be capitalized.
: 
: Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the 
: original Bell.  For example, SouthWestern Bell is a deciBell.

Out of what hat did you pull this one?  dB is a ratio not an RBOC!        

: And the measure of current, Amp, is actually named after both the AMP company
: and the Amphenol company.  Both companies revolutionized electronics by
: simulatenously realizing that the performance of connectors and sockets 
: were affected by the amount of current running through the wires.

Sorry.  The unit for current is the AMPERE which is the name of a french-man
named AMPERE who studied electrical current.  The term AMP is just an abbreviation
of it.  The company AMP came after the AMPERE unit was already in use.
  
: The Ohmite company was the first to characterize resistances by numbers, thus
: our use of the Ohms...

I don't know about this one, but it doesn't sound right.
  
: 
: Alexander Graham Bell, actually, is where Bell came from...  
Well you got one thing right!
: 
: 
: 
: Actually, Bel refers
: 
: >                          With highest regards,
: >                               Babak   Sehari.
: 
: >-- 
: -- 
: Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
: MSC 380 - Caltech  | 
: Pasadena, CA 91126 |   OS/2: The operating system of tomorrow, today.
: +1 818 449 5457    |   

Greg Moffatt
Bell-Northern Research Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
document_id: 52776
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr2.182216.28603@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:

|> |> Question 2:
|> |> 
|> |> 	If I am right about the doppler(if I spell it different every time,
|> |> maybe one will be right) effect, how does the radar get an accurate reading
|> |> when the car containing it is moving??  It would seem to me ( for all thats
|> |> worth) that it would need to be calibrated with the speedometer of the car
|> |> containing it??  I am fairly sure this isn't the case, so whats the deal??
|> 
|> Essentially, this is actually how it is done.  The radar gun is tied into
|> the speedometer of the car.

No, it is independent of the speedometer. The gun processes two doppler
returns--the speed of the car relative to the pavement and the speed
of the target, taking the difference between the two. Some guns with
a "moving mode" actually have a split beam with one beam aimed
preferentially at the pavement.

Car and Driver had a good article on traffic radar, but it was back in
1985. I used its contents and references to defend myself against a bogus
radar-measured ticket. It detailed "moving mode," which is easier to
defend against because of the increased amount of variables.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
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   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52777
From: scst83@csc.liv.ac.uk (Chris Smith)
Subject: Re: books/info on audio DSP ??

In sci.electronics,rec.audio David S. Rowell writes:

>I assume these are appropriate newsgroups for this question.  I am looking
>for a good book, articles, anything on audio DSP.  Theory is nice, but
>I'm really looking for something very much on the applications side.
>I want to look into it as my new hobby, so I need all the direction
>I can get.  Any comments would be welcome, too.

I'm looking to build a DSP for guitar processing. Hence lots of background
information would be really useful !

If anyone's got any info, could they email.....

Thanks in advance...

Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
document_id: 52778
From: gerald.belton@ozonehole.com (Gerald Belton)
Subject: PC games (joystick) port

>Subject says it all - could someone tell me the pinout
>for a PC type analogue joystick port?

Joystick A:
1        +5 VDC
2        Button 1
3        X Axis
4        Ground
5        Ground
6        Y Axis
7        Button 2
8        + 5 VDC
Joystick B:
9        +5 VDC
10        Button 1
11        X Axis
12        Ground
13        Y axis
14        Button 2
15        +5 VDC

---
 . SLMR 2.1 . Soft judges make hardened criminals.
                                                                                 
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Newsgroup: sci.electronics
document_id: 52779
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr2.182402.28700@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:

|> |> The 'beam' is split in two, with one beam aimed at the target car (sort of) and
|> |> the other at the ground.  The speeds of each are calulated for the final
|> |> number
|> 
|> Actually, this is true on the more expensive ones, but the cheaper ones
|> just read the speedometer.

I've never seen a speedometer-reading model. Are you sure? Who makes
them? Consider the difficulty of reading the speedo on various makes
of cars in use... I've seen single beam moving-mode and split beam
moving-mode.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
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   ******* Everywhere You Look (at least around my office) *******

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Newsgroup: sci.electronics
document_id: 52780
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: HV diodes

In article <1993Apr2.204617.14179@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
|> dtmedin@catbyte.b30.ingr.com (Dave Medin) writes:
|> >The CRT, in fact, does have an intentional built-in capacitor for
|> >its function just as IC's have built-in transistors, etc.
|> 
|> Gee, Mr. Myers, are we going to let this go without a CORRECTION?

Two things:

	1. Read your own posts. I was agreeing with Bob. No correction
	   needed.

	2. Don't quote stuff out of context.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52781
From: jsc52962@uxa.cso.uiuc.edu (Jeffrey S. Curtis)
Subject: Re: What is Zero dB????

moffatt@bnr.ca (John Thomson) writes:
}Out of what hat did you pull this one?  dB is a ratio not an RBOC!        
} [...]
}Sorry.  The unit for current is the AMPERE which is the name of a french-man
}named AMPERE who studied electrical current.  The term AMP is just an abbreviation
}of it.  The company AMP came after the AMPERE unit was already in use.
} [...]
}I don't know about this one, but it doesn't sound right.
} [...]
}Well you got one thing right!

Hello? John? Oh, nevermind...

Jeff
-- 
Jeffrey S. Curtis sidewinder@uiuc.edu | "Resplendent in full regalia, they
 The Power of 37  free2207 at uiucvmd | revel in their role as self-appointed
 Sony - Phase Linear - Sanyo - Sennet | critics of the establishment..."
 Jensen - Polk - StreetWires - Proton |   -- INXS _Welcome to Wherever You Are_

Newsgroup: sci.electronics
document_id: 52782
From: caryd@a.cs.okstate.edu (CARY DAVID ALLEN)
Subject:  Self-modifying hardware

Permit me to quote fragments of 
praetzel@sunee.uwaterloo.ca's article
out of context.

-Newsgroups: sci.electronics,comp.lsi.cad
-From: praetzel@sunee.uwaterloo.ca (Eric Praetzel)
-Date: 10 Feb 93 15:46:41 GMT

-  Currently the XNF format is propierty and I know of at least on person at
-a university who was able to get it after signing a non-disclosure agreement.
-The Xilinx-bit map format is pretty well top secret.  I would love to know it
-because then you could make self_modifying_hardware  ;-)  As it is I had to
-reverse eng. the Xilinx tools to dump the bit map to the FPGA because it only
-runs on the computer with the hardware key.

self-modifying hardware could be *very* interesting --
 computers that could write thier own programs (assemblers, compilers)
were an immense breakthrough from calculators that couldn't.

-  I eagerly await a programmable gate array which uses a PD format and does
-not cost your first born to program.  Till then we will keep on reverse
-engineering whatever we can.  As it is one company that I worked at has gone
-under.  FPGAs are what they needed to make their product competitive.  They
-could not afford them.  In the end you could say that they could not afford
-to not use them but the management discovered that too late. 
-   - Eric 

my condolences.

i can't even imagine what i could do with self-modifing hardware.
i *can* imagine self-modifying software,
and even though *all* my teachers say that's BAD, even Worse than GOTO,
check out what the experts *used* to say about self-modifying code:
(he uses "orders" rather than "opcodes")


"On the Principles of Large Scale Computing Machines"
by Goldstine and von Neumann,
collected in 
_John von Neumann: Collected Works, Vol. V_
reprinted here with absolutely no permission from anyone.
"We plan... to have a full size (40 binary digit) word hold
either contain
1 full size number (... equivalent to 12 decimal digits,
but we will use the first binary digit to denote the sign)
or two (20 binary digit) orders.
....
	It should be added that this technique of
automatic substitutions into orders,
i.e. the machine's ability to modify its own orders
(under the control of other ones among its orders)
is absolutely necessary for a flexible code. Thus, if
part of the memory is used as a "function table", then
"looking up" a value of that function for a value of the 
variable which is obtained in the course of the computation
requires that the machine itself should modify, or
rather make up, the reference to the memory in the order which
controls this "looking up", and the machine can only make this
modification after it has already calculated the value of the 
variable in question.
	On the other hand, this ability of the machine to modify its
own orders is one of the things which makes coding
the non-trivial operation which we have to view it as."

david cary, tenor, e- and comp. engineering (finger caryd@a.cs.okstate.edu).
227 S. 163 E. Ave, Tulsa, OK  74108-3310, USA, Sol 3, Universe v. 1.2

-- 
david cary, tenor, e- and comp. engineering (finger caryd@a.cs.okstate.edu).
227 S. 163 E. Ave, Tulsa, OK  74108-3310, USA, Sol 3, Universe v. 1.2

Newsgroup: sci.electronics
document_id: 52783
From: rsd@sei.cmu.edu (Richard S D'Ippolito)
Subject: Re: What is Zero dB????


In article <1pkveuINNduk@gap.caltech.edu>, Joseph Chiu writes:

> The Ohmite company was the first to characterize resistances by numbers, thus
> our use of the Ohms...


Yeah, right.  And the company was started by George Simon Ohmite.

Rich

Newsgroup: sci.electronics
document_id: 52784
From: jgd@dixie.com (John De Armond)
Subject: Re: Help with ultra-long timing

wellison@kuhub.cc.ukans.edu writes:

>I have a project that was drooped in my lap that is somewhat a pain to design.
>What I am looking for is a stable ultra-long solid state timer. What they want
>to do is to place this thing on the Antartic ice shelf and measure the amount
>of snow fall over a period of six weeks. Every two weeks, they want to trip a
>selonoid to discharge different colored pellets by gas pressure out across the
>snow. Then by digging down into the snow, the snow fall amount can be measured
>as they come to the different color pellets.

>The problem is trying to build a timer that would stand the cold (-40 degrees)
>and a power source that wouldn't drain. I have looked at the XR-2204 timers and
>the standard NE556 dual timers, but thier temp specs won't go that low. Also,
>two weeks equates to 1,209,600 seconds per firing, which means one big timing
>cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
>5 volts and are small in size. 

Why are you fooling around with analog for this job?  A single chip
micro and a crystal will do the job reliably and easily.  An 8748 only
costs about $5.  That and a $1 crystal and you're in business.  Embed
the whole thing in a foam insulated blanket, power it from a solar cell,
use the excess power to heat the assembly during the day and rely
on the insulation to hold the heat during darkness.  If you don't want
to try thermal management, contact someone like ICL and have them cut
you a special low temperature crystal.  It'll cost at most $20.

If you use a single chip micro, you're looking at a parts count of 
maybe 7.  A processor, a crystal, two caps on the crystal, a power FET
to fire the solenoid a flyback diode and a battery.  This is fewer parts than 
you can build an analog timer for and is infinitely more reliable.  Add
a power zener diode (for heat) and a solar cell and the parts count
screams up to 9.

PD assemblers are available for all the common single chip micros.  This
application is so trivial you could even look up the op codes in the 
programmer's guide and create the binary with a hex editor.

John
-- 
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Performance Engineering Magazine(TM) | Interested in high tech and computers? 
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Newsgroup: sci.electronics
document_id: 52785
From: jmichael@vnet.IBM.COM
Subject: Radar Detector DETECTORS?


They detect the oscillator operating in the detector. Saw a story about
their use in Canada. Now don't go putting oscillators in your cars... :-)

Newsgroup: sci.electronics
document_id: 52786
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Voltage Multiplier Problem.

Hi,

   I've just built a valve preamp and use a diode/capacitor
voltage multiplier to step the 12vAC supply voltage up to approx 
260vDV. As the load resistance increases, the RC constant decreases
and hence the output voltage drops. I need as high an output
voltage as possible. (about 260v).
  The circuit consists of seven voltage multiplier stages
(ie 14 diodes and 14 capacitors) each capacitor develops about 38v
across them, and I take the output from across seven capacitors=260v.
  Each capacitor is 100mfd at 68v.
 If I increase each of the capacitors rating (220-470mfd), that will
increase the RC constant, and hence alleviate some of the problem.
These capacitors are going to be a little expensive as I need 14 of
them, So:

1. What would happen if I connected a 470mfd at 400v capacitor in parallel 
with the output (and hence in parallel with the seven 100mfd capacitors)?
  Will it, as I assume, increase the C in circuit and hence increase
the RC time constant? If it does, and my output voltage becomes more
stable by doing this, then I will have killed two birds with one stone...
as I am experiencing some 50Hz ripple (and hence amp hum), and this new
capacitor will 'smooth' this out.

and
2. Can anyone recomend a suitable value for an inductor (choke) to
be placed in the output line of the power supply to filter out
the 50Hz mains hum. Lowest resistance possible !

  I've not got my preamp with me at the moment because it is TOO MUCH
of a distraction.... (I'm at university and I've got to get my 
dissertation finished in two weeks !!!!!!!) hence I'm mailing not
playing with my solderoing iron (it'll be cheaper too in the long
run... especially if 14 new large capacitors don't work as planned!)

Email please.... Can't always read the net.....

Thanks in advance..


Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
document_id: 52787
From: koops@gaul.csd.uwo.ca (Luke Koops)
Subject: Speaker design software?

Hi.  I'm looking for software to aid a friend of mine with designing speakers.
Does this type of software exist?  If anyone can point me toward a shareware or
freeware product with this description, that would be ideal.

...Steve van der Burg (using a friend's account)

(p.s. Excuse the terseness of the message;  I'm having difficulty stringing
readable sentences together today, for some reason.)

-- 

				-Luke Koops


Newsgroup: sci.electronics
document_id: 52788
From: jmichael@vnet.IBM.COM
Subject: Electric power line "balls"

Power lines and airplanes don't mix. In areas where lines are strung very
high, or where a lot of crop dusting takes place, or where there is danger
of airplanes flying into the lines, they place these plastic balls on the
lines so they are easier to spot.

Newsgroup: sci.electronics
document_id: 52789
From: behnke@FNALF.FNAL.GOV (M.L. 'Broomen' Behnke)
Subject: Re: Electric power line "balls"

In article <1993Apr6.203237.20841@eagle.lerc.nasa.gov>, fsset@bach.lerc.nasa.gov (Scott Townsend) writes:
>I got a question from my dad which I really can't answer and I'd appreciate
>some net.wisdom.
>
>His question is about some 18-24" diameter balls which are attached to
>electric power lines in his area.  He's seen up to a half dozen between
>two poles.  Neither of us have any experience with electric power distribution.
>My only guess was that they may be a capacitive device to equalize the
>inductance of the grid, but why so many between two poles?.
>
>Anyone know what they really are?  Is there a related FAQ for this?
>Is there a better group to submit to?
>
>We'd both appreciate some enlightenment.
>

 The balls are used to reduce the amplitude of oscillations of the wire during
periods of high winds.  I've seen what looks like paint cans filled with
concrete used for the same purpose.
Mike Behnke             | Senior Tech/Advisor | Quid est illuidin aqua??
Fermi Nat Accel Lab     | Equipment Suuport   |
Batavia, Il.            | Computing Div       | PISTRIX!!  PISTRIX!!
BEHNKE@FNALF.FNAL.GOV   |                     |

My opinions are my own, not of the lab. So, if you don't like them, call

1-800-UWH-INER

Newsgroup: sci.electronics
document_id: 52790
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Oscilloscope triggering

In article <C4vs0G.5ux@murdoch.acc.Virginia.EDU>, dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
|> >>Can someone out there explain exactly what the 'trigger'
|> >>feature found on oscilloscopes does?
|> >
|> 	{ lots og good explanation deleted}

<lots more deleted>
|> 	Is it just me, or does anybody else out there NOT like digital
|> scopes. My school has some beauutful 100Mhz HP that are digital with
|> all the bells and whistles, including soft-keys, which I think are a
|> loveley touch. ( that is, software keys. ) You don't forget that you
|> are dealing with a computer. Those scopes even with all their
|> neatness, still make the ickyest looking waves. Lotsa features, but
|> ugly output. And those are the best digitals I have ever seen. I've
|> seen a lot of cheaper digitals and they look terrible.

I think the hangup with digital scopes is that you have to know so much
more about them and how they work on a scope-by-scope basis, and
some of the functions are typically presented, in my opinion,
in a counter-intuitive fashion (HP has made some strides in their
54600 series, IMO). Automatic setups are fine for simple,
repetitive waveforms, but can give you some crazy results on more
complex events where you need to understand how the scope is
actually measuring/processing the event. For example, is the scope
in "equivalent time" or in "real time" sampling mode (equivalent time
being a mode where samples are built-up slowly by adding a delay to
the trigger event each sweep)? What was the scope's actual sampling
rate at the time? How is the data being massaged after capture but
before display, etc. One common misconception is the speed of the scope.

Is the HP scope you're using really a 100 MHz scope? Or is it a 20 MHz
sample rate scope (~5 MHz single shot significance) whose front
end including S/H can support 100 MHz waveforms (important for
equivalent time sampling)? The 100 MHz input in this case really
only helps you when your waveform is repetitive, or on a single
sample, when you get lucky and hit a transient event during a sample time.

So, there are a lot more variables in understanding how to get
useful information from a digital scope. I prefer an analog scope for
general use and the digital for events where I need storage for
later analysis or comparison, when the event is within the capability
of the scope. Now, for the price of true 100 MHz digital scopes to
fall...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52791
From: heinboke@tnt.uni-hannover.de (Andreas Heinbokel)
Subject: LOOKING for AD PC-Board

This is for a friend of mine. Please send answers directly to him (E-Mail
adress see below )!


HIGHSPEED  ANALOG-DIGITAL PC-BOARD

Hello LAdies and Gentleman !

I am looking for a highspeed A/D PC-Board with a sampling rate above 250 MHz an a
resolution of 8-bit. The sampling rate can be arranged by an interleave mode where
the time equivalent sampling yields 2, 4 or 8 times higher sampling rate than
the A/D-Converter uses in non interleave mode.

The board must content an A/D-Converter similar to Analog Devices AD 9028 or 
AD 9038 or if available a faster on.

If you a PC-Board (16-bit slot, ISA) with this specification or better, please
send me an EMail

hansch@cdc2.ikph.uni-hannover.dbp.de

or a Telefax to: ++49 / 511 / 7629353


Thanks in advance for your help !

Sincerely

     Matthias Hansch
     IKPH, University of Hannover, Germany



---

Andreas Heinbokel

heinboke@tnt.uni-hannover.de

*** ... all wisdom is print on t-shirts ***


Newsgroup: sci.electronics
document_id: 52792
From: gmc@cthulhu.semi.harris.com 
Subject: Re: What is Zero dB????

In article <1993Apr6.132429.16154@bnr.ca>
      moffatt@bnr.ca (John Thomson) writes:

 >Joseph Chiu (josephc@cco.caltech.edu) wrote:
 >
 >: Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the
 >: original Bell.  For example, SouthWestern Bell is a deciBell.
 >
 >Out of what hat did you pull this one?  dB is a ratio not an RBOC!
 >
 >: And the measure of current, Amp, is actually named after both the AMP company
 >: and the Amphenol company.  Both companies revolutionized electronics by
 >: simulatenously realizing that the performance of connectors and sockets
 >: were affected by the amount of current running through the wires.
 >
 >Sorry.  The unit for current is the AMPERE which is the name of a french-man
 >named AMPERE who studied electrical current.  The term AMP is just an abbreviation
 >of it.  The company AMP came after the AMPERE unit was already in use.
 >
 >: The Ohmite company was the first to characterize resistances by numbers,
 >: thus our use of the Ohms...
 >
 >I don't know about this one, but it doesn't sound right.
 >
 >:
 >: Alexander Graham Bell, actually, is where Bell came from...
 >Well you got one thing right!
 >:

Actually, I think J. Chiu knows the score and is just being
silly. However, "decibel" is in fact 1/10th of a bel. He is
right on that one, but I don't know if it was accidental or not.

Strictly defined, a bel is the ratio of the log of two power levels,
and a decibel is 1/10th of a bel so you have 10X decibels for every bel,
hence bel=log(P2/P1) and decibel=10Xlog(P2/P1).

The bel, ohm, volt, farad, ampere, watt, hertz, henry, etc. are
all named for pioneers in the field. It's a traditional and fine
way to honor researchers who discover new knowledge in a new field.
Hertz was one of the most important of the early electronics explorers,
but had been left out in having a term or unit named after him
until recently, (1960's, prior to that what is now a hertz was a cps.)
All the other units were defined many decades earlier.


 


-- 
----------------------------------------------------------------------




----------------------------------------------------------------------


Newsgroup: sci.electronics
document_id: 52793
From: cab@col.hp.com (Chris Best)
Subject: Re: Police radar....Just how does it work??

I've seen several references to split- or separate-beam radars, which I
claimed didn't exist.  Gotta eat some crow here - I wasn't aware of them.
All I really knew was that it can be done with one beam.

I believe the rest of what I said is accurate, though.

Mmmmmmm....crow.... (oops-wrong group)

Newsgroup: sci.electronics
document_id: 52794
From: ragee@vdoe386.vak12ed.edu (Randy Agee)
Subject: Radar detector DETECTORS?

Here's one I hope some knowledgeable readers will make a comment or
contribution to:

In the State of Virginia radar detectors are illegal, period.  If
you are caught with one it will be confiscated on the spot and will
not be returned until after you appear in court and pay your fine. 
The fine for having a radar detector accessible in a motor vehicle
(even if it is not on) is $250.00.  Sorry, tourist, ignorance of
the law is no excuse - they will get you too!

It used to be that the only way the law could be enforced was for
an officer to actually see the radar detector.  Not any more!  Many
law enforcement agencies are now using radar detector detectors. 
Right, a super sensitive receiver that is capable of picking up RF
from the radar detector itself.  My first reaction was "no way!" 
But, guess again, these little buggers really work and the police
are writing citations right and left for people using radar
detectors.  One news story quoted an officer as saying that he had
found the radar detector in all of the cars he stopped except one,
and he could never figure out where it was - but he knew it was
there.  This tends to make one assume there are few false arrest.

Now, before I get flamed, please understand that I do drive at or
near the speed limit.  I do not need a radar detector to keep me
from getting a speeding ticket.  But, I do like to know when my
speed is being clocked or a speed trap is functioning.  My radar
detector now stays locked in my trunk when I am in Virginia (which
is what they want - and yes, what the law says, and I intend to
obey the law!) and is only used in states where it is legal.

For my fellow hams, I am not a microwave person - my mind only
works in the HF spectrum between 10 and 80 meters.  Microwave
enlightment may be necessary.

So, the questions are -
  What do the radar detector detectors actually detect?
  Would additional shielding/grounding/bypassing shield stray RF generated by
  a radar detector, or is the RF actually being emitted by the detector
  antenna?
  Are any brands "quieter" than others?

==============================================================================
Randy T. Agee - ARS WB4BZX       | At some point, you probably pondered The 
P.O. Box 2120 - 20th floor       | Meaning of Life, and you came up with a 
Virginia Department of Education | satisfactory answer, which has or has not
Richmond, VA 23216-2120          | stood the test of time, or you shrugged
Phone (804) 225-2669             | mightily, muttered "Beats the heck out of
ragee@vdoe386.vak12ed.edu        | me," and ordered a cheeseburger.
=============================================================================
 

Newsgroup: sci.electronics
document_id: 52795
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Re: Why is telephone audio 300-3000 Hz?


>> telephone systems have the capability of a passband of 30hz to 4Khz.
>> The reason they do not implement this is: It is not backward compatable
>> to every telephone system.  In addition, the most effecent mix of 
>> electrical effecency, and intelegability closly mateches a 300hz-3khz
>> passband.
>
>Close, but no banana (to paraphrase Garfield)...
>The reason 300-3300 Hz is used is that voice channels used to occupy
>4kHz bands when multiplexed on a trunk line. Therefore, 300Hz at the
>bottom, and 700Hz at the top of this band were filtered to minimise
>interference with the next band.
>
>Nowadays, digital trunks have made this less relevant, but the phone
>companies still see no reason to improve quality (especially for free!).
>Therefore, digital "chunk of a trunk" segments still have a guaranteed
>bandwidth of only 4kHz (so they can carry the equivalent of one analog
>line) at the clock rate of a standard PCM T1 or E1 digital trunk.
>
>It's all historical...


Here in the UK, the bandwidth restriction apparently only apply to 
local lines.. ie those used by the average domestic client. Private
lines which are run from the local exchange to the leasing client are 
usually capable of a higher bandwidth if the exchange is digital.

Don't quote me on that..... But I think I remember a BT engineer 
saying something to that effect when I was doing some work
shadowing a few years ago.

Byeeeee !


Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
document_id: 52796
From: rivero@sol.cie.unizar.es
Subject: Video IO ideas?

Have anyone some idea about how to build a cheap, low
resolution (or high :-) video projector... 

(example: a LCD and an slide projector)
.



Newsgroup: sci.electronics
document_id: 52797
From: linnig@m2000.dseg.ti.com (Mike Linnig)
Subject: Re: books/info on audio DSP ??

In article <C52DsD.7pB@compsci.liverpool.ac.uk> scst83@csc.liv.ac.uk (Chris Smith) writes:

> I'm looking to build a DSP for guitar processing. Hence lots of background
> information would be really useful !
> 
> If anyone's got any info, could they email.....

Well, I'm not sure I'd use this to process a guitar but there was a audio
filter DSP construction article in the Sept 92 issue of QST magazine (Ham Radio
oriented).  The DSP is available in kit form for about $120.

This particular DSP filter was targetted toward processing audio to remove
noise (static).  I built it and it really works well.  The source code is
available too.  It makes a noisy audio signal much easier to hear.  Note that
this is for communication applications and is not "high fidelity".



--
- - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - +
Mike Linnig, Texas Instruments Inc. | 97.43% of all statistics are made |
Phone: (214) 575-3597  CALL: N5QAW  | up; most of them (83.6 percent)   |
Internet: mike.linnig@dseg.ti.com   | are wrong.                        |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


Newsgroup: sci.electronics
document_id: 52798
From: mpaul@unl.edu (marxhausen paul)
Subject: How to kill AC inductive load spiking?

Is there a fast 'n dirty way to kill the line spiking that occurs when
an inductive load is turned on sometime other than at zero-crossing of
the AC cycle?  A capacitor kludged in somehow, etc?

I've got a microcontroller that is running a bunch of valves and pumps
in a big instrument washer, and almost everything is being switched with
zero-crossing solid state relays, so that stuff stays "quiet", AC-wise.
But there's one steam valve that gets turned on by a mechanical relay
in the water tank fill/thermostat system, and it's not under control
of my SSRs, and it does sometimes generate/radiate a spike that resets
one of my peripheral chips.  My software times out and tries again, but
I'd love to just tack in a magic spike-killing fix that would avoid having
to do some major rewiring/redesign.  A varistor would help but might not
be sufficient.  Ideas?

--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
document_id: 52799
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr6.161107.2235@b30news.b30.ingr.com>, dtmedin@catbyte.b30.ingr.com (Dave Medin) writes:
|> In article <1993Apr2.182402.28700@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:
|> 
|> |> |> The 'beam' is split in two, with one beam aimed at the target car (sort of) and
|> |> |> the other at the ground.  The speeds of each are calulated for the final
|> |> |> number
|> |> 
|> |> Actually, this is true on the more expensive ones, but the cheaper ones
|> |> just read the speedometer.
|> 
|> I've never seen a speedometer-reading model. Are you sure? Who makes
|> them? Consider the difficulty of reading the speedo on various makes
|> of cars in use... I've seen single beam moving-mode and split beam
|> moving-mode.

Obviously the police officer reads the speedometer.
I cannot believe the nit-picking in this group.
There's 2 beams, there is not, is too, etc....

|> --------------------------------------------------------------------
|> [Dave Medin's 10 line sig deleted]


Newsgroup: sci.electronics
document_id: 52800
From: nhowland@matt.ksu.ksu.edu (Neal Patrick Howland)
Subject: Re: Radar detector DETECTORS?

ragee@vdoe386.vak12ed.edu (Randy Agee) writes:

>It used to be that the only way the law could be enforced was for
>an officer to actually see the radar detector.  Not any more!  Many
>law enforcement agencies are now using radar detector detectors. 
>Right, a super sensitive receiver that is capable of picking up RF
>from the radar detector itself.  My first reaction was "no way!" 
>But, guess again, these little buggers really work and the police
>are writing citations right and left for people using radar
>detectors.  One news story quoted an officer as saying that he had
>found the radar detector in all of the cars he stopped except one,
>and he could never figure out where it was - but he knew it was
>there.  This tends to make one assume there are few false arrest.

From what I understand about radar dectectors all they are is a passive
device much like the radio in your car.  They work as an antenna picking
up that radar signals that the radar gun sends out.  Therefore there would
be no way of detecting a radar detector any more than there would be of
detecting whether some one had a radio in their car.  

Neal Howland
nhowland@matt.ksu.ksu.edu 


Newsgroup: sci.electronics
document_id: 52801
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Where do U look??

In article <1993Apr2.170955.1749@cmkrnl.com>, jeh@cmkrnl.com writes:

|> I might add that collecting last year's data books (or even ones two years out
|> of date) is usually pretty cheap, and has benefits besides:  You usually DON'T
|> want to base a design on a brand-new chip.  There may be bugs; availability may
|> be limited; the data sheets may be missing critical information that will show
|> up in the ap notes in next year's data books.  Kinda like buying Version 1.0 of
|> a major new software package:  Sometimes you get lucky, but don't count on it.

There are two more reasons to save old databooks and then beyond two
years--obsoleted parts and better application notes and tutorials.

When a part is dropped from future production planning, such as the
National MM-series white noise generators, camera sync generators, etc.,
it will disappear from current databooks although it still may be produced
for a short time (or be available from stock somewhere). Now, if you
have some old plans calling for such a device, or you have a dead
gadget on your workbench and it has such a part in it, you'll know
the functions so you can troubleshoot and substitute as necessary.

The old GE thyristor data books contain real good tutorials on
SCR and triac applications that are not found elsewhere, for
example.

|> > In summary, read. READ! ****READ!!!**** That's how you'll know what to
|> > design in, which parts to use, and how to solve the intractable problem
|> > that your boss has presented you with. 
|> 
|> It helps to have a prodigous memory for details...

Here, here!...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 52804
From: corleyg@ul.ie
Subject: Microstrip help wanted

I need information on microstrip circuit design especially 
filter design for the 1-3GHz range. Can you recommend any
good books, journals, or microstrip circuit design software.
.
all help appreciated

Gerry Corley, ECE Department, Univesity of Limerick, Ireland.


Newsgroup: sci.electronics
document_id: 52805
From: dpalmer@mcnc.org (W. Dev Palmer)
Subject: Re: Wanted: A to D hardware for a PC

In article <1993Apr6.053736.23113@doug.cae.wisc.edu> kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:
>>
>>>	If you know much about PC's (IBM comp) you might try the joystick
>>>port.  Though I haven't tried this myself, I've been told that the port
>
>I believe that the "A-D converters" found on a joystick port are really
>timers that tick off how long it takes an R-C circuit (the R being your
>paddle) to charge up to something like 1/2 Vcc.  For games this works
>pretty well, but you certainly wouldn't want to try to take lab
>measurements off something as non-linear as that.

The best info I have seen so far is the article "Joystick Metrics:
Measuring physical properties through the PC's joystick port" by
Michael Covington in the May 1985 issue of PC Tech Journal.  It talks
about how to read all kinds of things (voltage, current, resistance) in
BASIC, and even includes code for a simple "oscilloscope" display.

It's possible to read the joystick port directly if you don't want to
use BASIC.  The detailed information for this is in the PC Technical
Reference under Options and Adapters.  You have to provide some
millisecond resolution timing functions, but that's a subject which has
appeared many times in articles from Dr. Dobb's, Circuit Cellar Ink,
etc.  Look for the public domain ztimer package on wuarchive.

Good Luck,

Dev Palmer
dpalmer@mcnc.org
MCNC Room 212
P.O. Box 12889
RTP, NC  27709-2889
(919) 248-1837
(919) 248-1455 FAX

Newsgroup: sci.electronics
document_id: 52806
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Peltier Effect Heat Pumps


I was having a look through a couple of components catalogues when I
came across a range of Peltier Effect heat pumps intended for cooling
components.  For those who have not heard of this effect, you put a
current through one of these devices, and it pumps heat from one side
to the other.  Reverse the current and you reverse the effect.  I
think a temperature difference can give you an EMF as well.

Anyway, it struck me that you could make a nice cool/hot box for
picnics with one of these, a power regulator, a thermostat and a
couple of heat sinks.  The biggest device can shift 60W with an
efficiency of 80-90%, which ain't bad (although it would flatten my
car battery in about half an hour).

Unfortunately the catalogue didn't list anything more than the basic
specs as a heat pump.  I imagine that you would get a back-EMF as the
temperature gradient across the device increases.  If so, presumably
its power decreases as the back-EMF increases, until eventually we
have a steady state with no current being consumed (assuming no
leakage).  If so, then the final temperature difference between the
two sides could be set by the supply voltage and nothing more
(although that would be a lousy way to control it).

What I would like to know is:

1: Are the above guesses correct?

2: What is the open-circuit thermal resistance of a typical device?
   (I just want to be sure that my coolbox is not going to get warm
   too fast when I unplug it)

3: How does a Peltier Effect heat pump actually work?  It looks like
   magic!

4: Why don't they use these things in domestic fridges/freezers?


Thanks in advance,

Paul.

Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
document_id: 52807
From: sciamanda@edinboro.edu
Subject: Re: Outdoor FM Antennas

In article <beerb.9.0@ccmail.dayton.saic.com>, beerb@ccmail.dayton.saic.com (Bradlee Beer) writes:
> I'm interested in buying or building an omnidirectional antenna for the 
> commercial FM band (88-108MHz).  The commonly sold ones are a folded dipole 
> bent in an "S" shape; and one with a pair of crossed dipoles.  I don't see 
> either of these designs as exhibiting any gain, and they probably aren't 
> truely omnidirectional.
> 
> 
> I'm intrigued by the discone antenna.  Does anyone have detailed information
> on how to design one for the FM band (with 75-ohm impedence)??  Is one
> commercially available??  Are there other designs that have GAIN??  
> 
> I already own a 10-element FM yagi.  It works great, but requires frequent 
> rotation for those distant stations.  
> 
> Brad Beer,  4414 Castle Gate Drive,  Beavercreek, OH  45432-1814

Brad,
   For an antenna, gain is synonymous with directionality.  The only way 
to get gain (>1) out of an antenna is to design in directionality. The 
"gain" of an antenna is defined as the signal increase (for a preferred 
direction) over the signal obtained by an isotropic antenna.

Bob Sciamanda
Edinboro Univ of PA

Newsgroup: sci.electronics
document_id: 52808
From: row0@ns1.cc.lehigh.edu (RICHARD O. WHITE)
Subject: Re: Help with ultra-long timing


In article <1993Apr5.083324.48826@kuhub.cc.ukans.edu>, wellison@kuhub.cc.ukans.e
du writes:
>I have a project that was drooped in my lap that is somewhat a pain to design.
>What I am looking for is a stable ultra-long solid state timer. What they want
>to do is to place this thing on the Antartic ice shelf and measure the amount
>of snow fall over a period of six weeks. Every two weeks, they want to trip a
>selonoid to discharge different colored pellets by gas pressure out across the
>snow. Then by digging down into the snow, the snow fall amount can be measured
>as they come to the different color pellets.
>
>The problem is trying to build a timer that would stand the cold (-40 degrees)
>and a power source that wouldn't drain. I have looked at the XR-2204 timers and
>the standard NE556 dual timers, but thier temp specs won't go that low. Also,
>two weeks equates to 1,209,600 seconds per firing, which means one big timing
>cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
>5 volts and are small in size. But again, the time of discharge at -40 or lower
>degrees isn't linear. I was thinking of using several timers chained together
>to fire the selonid at the end of the timing period, but that blasted cold and
>the drain on a battery over six weeks is the pain. One possibility would be to
>use solar panels, but this is during the six month twilight. Anyone have any
>good ideas ?
>
>Thanks in advance...
>
>-=-= Wes =-=-
>
just a suggestion:
take a motorola mc14536B set it up to give you a pulse once every sec or ten
secs with either a RC or xtal clock input. then feed to a MC14521B as clock
input and decode output for 1,209,600 sec output ,might have to add a few 'and'
gates or decoder chips to get output and reset pulse back to the'521 to restart
cycle... Trigger a oneshot from the decoded riseing edge ;the one shot then
goes to a mosfet to drive the mechanism to fire the pellet launcher..
these ckts require uAmps of current,between 5 - 15 volts, so a 12 volt
gel cell of a few Amphours would last the six weeks.
Then take the ckt board & battery wrap in 3" or 4" of foam or build a box
of out of the stuff...with plywood or metal exterior...
build a small heater out of 10-50 Watt resistors in series to keep the battery
and ckts warm.
2nd thought use 2 batteries one for heater one for timer and pellet trigger.

Insolate-insolate.......even though the chips state that the - AL
rated devices are good to -55 C.. The batteries have a considerable reduction
in capacity...oh make sure the area inside has minium air leakage..

hope this helps
RW     ( is this to long winded for the net??)(be gentle)...
-- 

Newsgroup: sci.electronics
document_id: 52809
From: rg@futserv.austin.ibm.com (R.G. Keen)
Subject: Re: All Electronics Press and Peel PCB transfer

I think there is a huge difference in the materials and 
process for printer/toner PCB's. I get first time, everytime
results from a local HP Postscript, and hardly ever works from
copies of the same artwork. The printer results are so good
that I have quit even looking for PC board processes. If I had
to use the copier version, I would think I would look elsewhere.
The moral? Experiment and find what works. Toner transfer CAN
give excellent results. It, like any process, gives erratic 
results with variable inputs.

R.G.


Newsgroup: sci.electronics
document_id: 52810
From: fsset@bach.lerc.nasa.gov (Scott Townsend)
Subject: Electric power line "balls"

I got a question from my dad which I really can't answer and I'd appreciate
some net.wisdom.

His question is about some 18-24" diameter balls which are attached to
electric power lines in his area.  He's seen up to a half dozen between
two poles.  Neither of us have any experience with electric power distribution.
My only guess was that they may be a capacitive device to equalize the
inductance of the grid, but why so many between two poles?.

Anyone know what they really are?  Is there a related FAQ for this?
Is there a better group to submit to?

We'd both appreciate some enlightenment.


-- 
Scott Townsend,  Sverdrup Technology Inc.  NASA Lewis Research Center Group
fsset@bach.lerc.nasa.gov

Newsgroup: sci.electronics
document_id: 52811
From: jack@multimedia.cc.gatech.edu (Tom Rodriguez)
Subject: composite video - what are HD and VD?


	I've got an rgb Mistubishi monitor and on the back it has 5
BNC connectors labeled like this:

    composite
  HD          VD
  +           +        +       +       +
             sync     red    green    blue

	I've used it as a straight RGB monsitor but i can't figure out
how to use it for composite.  Could someone explain what these markings
mean?  Thanks for any help.

	tom
--
Tom Rodriguez  (jack@cc.gatech.edu)
Multimedia Computing Group - GVU Lab
Georgia Institute of Technology
Atlanta, Georgia 30332-0280

Newsgroup: sci.electronics
document_id: 52812
From: gerg@netcom.com (Greg Andrews)
Subject: Re: Radar detector DETECTORS?

nhowland@matt.ksu.ksu.edu (Neal Patrick Howland) writes:
>
>From what I understand about radar dectectors all they are is a passive
>device much like the radio in your car.  They work as an antenna picking
>up that radar signals that the radar gun sends out.  Therefore there would
>be no way of detecting a radar detector any more than there would be of
>detecting whether some one had a radio in their car.  
>

Unfortunately, you're wrong on both counts.  The most common method of
implementing a tunable receiver is to have a local oscillator.  The
local oscillator's frequency can be radiated out of the receiver via
the antenna unless the circuit is designed and constructed with great
care.

For a reference on detecting radios, get the paperback book _Spy Catcher_.
The author discovered how to detect radio receivers from their local
oscillator emissions back in the *1950s* while he worked for British
Intelligence.

  -Greg
-- 
:::::::::::::::::::  Greg Andrews  gerg@netcom.com  :::::::::::::::::::
Fortune Cookie:  Radioactive cats have 18 half-lives.
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Newsgroup: sci.electronics
document_id: 52813
From: behnke@FNALF.FNAL.GOV (M.L. 'Broomen' Behnke)
Subject: Re: Peltier Effect Heat Pumps

In article <2745@snap>, paj@uk.co.gec-mrc (Paul Johnson) writes:
>
>I was having a look through a couple of components catalogues when I
>came across a range of Peltier Effect heat pumps intended for cooling
>components.  For those who have not heard of this effect, you put a
>current through one of these devices, and it pumps heat from one side
>to the other.  Reverse the current and you reverse the effect.  I
>think a temperature difference can give you an EMF as well.
>
>Anyway, it struck me that you could make a nice cool/hot box for
>picnics with one of these, a power regulator, a thermostat and a
>couple of heat sinks.  The biggest device can shift 60W with an
>efficiency of 80-90%, which ain't bad (although it would flatten my
>car battery in about half an hour).
>
 So-Called Cool-Hot boxes have been advetised for several years.  I recall
Damark advertising them in a recent catalog.  Problem with the units is they do
a sh***y job of keeping food cold/warm.  The peliter devices used just don't
seem to have enough punch to keep up.  If you want something hot, you need to
heat it up before you put it in the box, and end up hours later with food thats
only moderately warm.  Same goes for cold items.

>Unfortunately the catalogue didn't list anything more than the basic
>specs as a heat pump.  I imagine that you would get a back-EMF as the
>temperature gradient across the device increases.  If so, presumably
>its power decreases as the back-EMF increases, until eventually we
>have a steady state with no current being consumed (assuming no
>leakage).  If so, then the final temperature difference between the
>two sides could be set by the supply voltage and nothing more
>(although that would be a lousy way to control it).
>
>What I would like to know is:
>
>1: Are the above guesses correct?
>
>2: What is the open-circuit thermal resistance of a typical device?
>   (I just want to be sure that my coolbox is not going to get warm
>   too fast when I unplug it)

 You'de probably be better off getting a good Coleman(tm) cooler and stocking
up on "blue ice" blocks.

>
>3: How does a Peltier Effect heat pump actually work?  It looks like
>   magic!
>
>4: Why don't they use these things in domestic fridges/freezers?
>
 Same as above.  Not enough "punch" in them to keep/get things cold/hot.
>
>Thanks in advance,
>
>Paul.
>
>Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
>--------------------------------------------+----------------------------------
>These ideas and others like them can be had | GEC-Marconi Research is not
>for $0.02 each from any reputable idealist. | responsible for my opinions
Mike Behnke             | Senior Tech/Advisor | Quid est illuidin aqua??
Fermi Nat Accel Lab     | Equipment Suuport   |
Batavia, Il.            | Computing Div       | PISTRIX!!  PISTRIX!!
BEHNKE@FNALF.FNAL.GOV   |                     |

My opinions are my own, not of the lab. So, if you don't like them, call

1-800-UWH-INER

Newsgroup: sci.electronics
document_id: 52814
From: sidhu@ee.ualberta.ca (Kenneth Sidhu)
Subject: Dimming Incand. Lamps


 
  
  
What's the latest and greatest way to dim incandescent lamps ?

March '93 Circuit Cellar has part one of an article about
dimming 120VAC lamps, but it seems to lead into phase-
control as the best method for controlling brightness.
  I've always hated phase-control for the RFI, buzzing
filaments and non-linear adjustment range. I had
heard that you can modulate the AC line on a cycle by
cycle basis to get better results. To cut the lamp's
power to 50% you would givemsay 20 cycles of AC, then
nothing for another 20 cycles. I wonder if anyone has
tried this or knows what the pro stuff is using. Any
advice is appreciated!

Ken


email: sidhu@bode.ee.ualberta.ca

Newsgroup: sci.electronics
document_id: 52815
From: gtalatin@vartivar.ucs.indiana.edu  (Gerard V. Talatinian)
Subject: Low cost oscilloscopes?

I am looking at buying a low cost (< $500) scope for general purpose use.
Any recommendations? Is this info in a faq somewhere?
Any pointers appreciated.
Thanks,
  -Gerard.

******************************************************************
* Gerard Talatinian                 |                            *
* Network Systems                   |   gtalatin@ucs.indiana.edu *
* University Computing Services     |   FAX:   (812) 855-8299    *
* Indiana University                |   Voice: (812) 855-0962    *
******************************************************************

Newsgroup: sci.electronics
document_id: 52816
From: ritley@uimrl7.mrl.uiuc.edu ()
Subject: SEEKING THERMOCOUPLE AMPLIFIER CIRCUIT



I would like to be able to amplify a voltage signal which is
output from a thermocouple, preferably by a factor of
100 or 1000 ---- so that the resulting voltage can be fed
more easily into a personal-computer-based ADC data
acquisition card.

Might anyone be able to point me to references to such
circuits?  I have seen simple amplifier circuits before, but
I am not sure how well they work in practice.

In this case, I'd like something which will amplify sufficiently
"nicely" to be used for thermocouples (say, a few degrees
accuracy or better).

Any pointers would be greatly appreciated!

Newsgroup: sci.electronics
document_id: 52817
From: bailey@vader.egr.uri.edu (Scott Bailey)
Subject: Re: Jacob's Ladder

Hi all,
 I've been following this thread about jacob's ladder for a few weeks and I
happened to come across one of the best project books that I've seen in a 
while.  The book "Gadgeteer's Goldmine" by Gordon McComb offers over 55 
excellent low cost projects including: Jacob's Ladder, tesla coils, plasma 
spheres, a Van de Graaff generator, robots, an IR scope, and several laser 
projects.  The instructions come with complete part lists, warnings and 
diagrams.  For those of you who are interested in building any of the above 
listed projects, you should seriously consider getting this book.  The 
paperback version is only $19.95 too.

For those who want more information:
Title: Gadgeteer's Goldmine!  55 Space-Age Projects
Auth:  Gordon McComb
Pub:   TAB Books
CW:    1990
ISBN:  0-8306-8360-7
	0-8306-3360-X (paperback)
 Price: $19.95 (paperback)

 -Scott

/-----------------------------------------------------------------------------\
| Scott A. Bailey            | #include "std_disclaimer.h"                    |
| ECL Operator               |------------------------------------------------|
| Computer Engineering       | I'm just a knight who chases the moon...       |
| University of Rhode Island | Haven't caught it yet,but I haven't let that   |
| bailey@vader.egr.uri.edu   | keep me from still trying each day and night   |
| bailey@ecl1.uri.edu        |    --(----------           ----------)--       |
\-----------------------------------------------------------------------------/

Newsgroup: sci.electronics
document_id: 52818
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: What is Zero dB????

In article <1993Apr6.092913.18724@sei.cmu.edu> rsd@sei.cmu.edu (Richard S D'Ippolito) writes:
>
>In article <1pkveuINNduk@gap.caltech.edu>, Joseph Chiu writes:
>
>> The Ohmite company was the first to characterize resistances by numbers, thus
>> our use of the Ohms...
>
>
>Yeah, right.  And the company was started by George Simon Ohmite.

That's completely inaccurate.  The ohm was an original standard made equal
to a the resistance of a standardized electric stove heating element.  That's
where the song "Ohm on the Range" came from, of course.
--scott

Newsgroup: sci.electronics
document_id: 52819
From: zstewart@nyx.cs.du.edu (Zhahai Stewart)
Subject: Re: Police radar....Just how does it work??

>The father of a friend of mine is a police officer in West Virginia.  Not  
>only is his word as a skilled observer good in court, but his skill as an  
>observer has been tested to be more accurate than the radar gun in some  
>cases . . ..  No foolin!  He can guess a car's speed to within 2-3mph just  
>by watching it blow by - whether he's standing still or moving too!  (Yes,  

1) How was this testing done, and how many times?  (Calibrated speedometer?)

2) It's not the "some cases" that worry me, it's the "other cases" :-)

(eg: suboptimal viewing conditions; even the best subjective viewer can only
partial compensate for certain distortions and optical illusions).


Newsgroup: sci.electronics
document_id: 52820
From: gleasokr@rintintin.Colorado.EDU (Kris Gleason)
Subject: Re: Electric power line "balls"

fsset@bach.lerc.nasa.gov (Scott Townsend) writes:

>I got a question from my dad which I really can't answer and I'd appreciate
>some net.wisdom.

>His question is about some 18-24" diameter balls which are attached to
>electric power lines in his area.  He's seen up to a half dozen between
>two poles.  Neither of us have any experience with electric power distribution.
>My only guess was that they may be a capacitive device to equalize the
>inductance of the grid, but why so many between two poles?.

>Anyone know what they really are?  Is there a related FAQ for this?
>Is there a better group to submit to?

>We'd both appreciate some enlightenment.

I think those are to make the lines more visible to airplanes and
helicopters... cheaper than blinking red lights.

'course I could be wrong.

Kris


Newsgroup: sci.electronics
document_id: 52821
From: depolo@eniac.seas.upenn.edu (Jeff Depolo)
Subject: Need manual for HP 1740 scope


I have a HP 1740 scope that (I think) has a problem in the HV section.
Symptom: started turning on and off on its own, making intermittant
bright flashes on the CRT, and then finally, passed away.  If you
have a manual (or any suggestions), please send me mail.  Will gladly
pay reproduction/shipping costs plus a little $ for your efforts for
the manual.  Thanks in advance.

								--- Jeff
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 Jeff DePolo  WN3A              Twisted Pair: (215) 337-7383H  387-3059W  
 depolo@eniac.seas.upenn.edu    RF: 443.800+ MHz    442.700+ MHz    24.150 GHz
 University of Pennsylvania     

Newsgroup: sci.electronics
document_id: 52822
From: mneideng@thidwick.acs.calpoly.edu (Mark Neidengard)
Subject: Re: What is Zero dB????

>>: The Ohmite company was the first to characterize resistances by numbers, thus
>: our use of the Ohms...
>
>I don't know about this one, but it doesn't sound right.

DAMN RIGHT it doesn't!  Ohm's come from the greek letter omega, which
is used for resistance/impedance.

Of course, the original poster MAY have been being facetious (let's hope
so).

Mark Neidengard
mneideng@cosmos.acs.calpoly.edu

Newsgroup: sci.electronics
document_id: 52823
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Subject: Re: few video questions

In article <7480224@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>situation sometimes called "block" sync).  You can generate such a combined
>(or "composite") sync in two simple ways - OR the H. and V. syncs together,
>which gives you the non-serrated "block" sync, or EXOR them, which makes
>serrations.  (Try it!)  Actually, the EXOR doesn't really do kosher serrated
>sync, since it puts the rising (and falling, for that matter) edge of the H. 
>sync pulse off by a pulse width.  But that usually makes no difference.

Sometimes.  It depends on your monitor and your timing.  If you don't
have enough vertical front porch and you use XOR composite sync you can
get even/odd tearing at the top of the screen, which is very sensitive
to the HHOLD control.  It looks like what you would expect if you
scanned the even fields (say) onto a sheet of mylar and had pinched the
upper left corner with your fingers and started to tear it off the tube. 
With proper composite sync (equalizing pulses) the interlace is rock
solid. 

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			One Design to rule them all; one Design to find them.
			One Design to bring them all and in the darkness bind
			them.  In the land of Mediocrity where the PC's lie.

Newsgroup: sci.electronics
document_id: 52824
From: dzenc@hal.gnu.ai.mit.edu (Dan Zenchelsky)
Subject: VIdeotext/teletext descrambler

Hi,

I am looking for a PC card which does european videotext/teletext
descrambling (PAL). Does anyone in the US sell such a card? I once
saw an article about a card with the same functionallity in a
european Elektor magazine, but I wasn't able to track it down.

Thanx in advance,
Dan

Newsgroup: sci.electronics
document_id: 52825
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Electric power line "balls"

In article <1993Apr6.203237.20841@eagle.lerc.nasa.gov>,
fsset@bach.lerc.nasa.gov (Scott Townsend) wrote:
> 
> I got a question from my dad which I really can't answer and I'd appreciate
> some net.wisdom.
> 
> His question is about some 18-24" diameter balls which are attached to
> electric power lines in his area.  He's seen up to a half dozen between
> two poles.  Neither of us have any experience with electric power distribution.
> My only guess was that they may be a capacitive device to equalize the
> inductance of the grid, but why so many between two poles?.
I'll bet there's a runway nearby.

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
document_id: 52826
From: smithr@teecs.UUCP (Robert Smith)
Subject: Re: Conductive Plastic, what happened?

If you're thinking of reactive polymers they're making ESD safe
contauiners out of it. As far as being conductive goes anything with
a resistance less than 10 to the fouthrth power ohms per cubic measure
is classed as conductive per MIL-STD-1686 for ESD protection. My $0.02
($0.016 US).

Bob.

Newsgroup: sci.electronics
document_id: 52827
From: young_dick@macmail2.rtsg.mot.com (Dick Young)
Subject: ATTN: H. Wheaton, UCal Davis

I tried to E-mail you, but the message bounced.

Motorola has a University Support Program through which (I've been told) folks
at schools can get sample quantities of parts.  If you'd like to try this 
route, e-mail me for the address/phone #...I don't wish to post it for all the
world to see.

Dick Young
Motorola, Inc.
(Who doesn't have a thing to do with my opinions: They're my own fault.)


Newsgroup: sci.electronics
document_id: 52828
From: advax@reg.triumf.ca (A.Daviel)
Subject: Re: Radar detector DETECTORS?

In article <1pslckINNmn0@matt.ksu.ksu.edu>, nhowland@matt.ksu.ksu.edu (Neal Patrick Howland) writes...
> 
>From what I understand about radar dectectors all they are is a passive
>device much like the radio in your car.  They work as an antenna picking
>up that radar signals that the radar gun sends out.  Therefore there would
>be no way of detecting a radar detector any more than there would be of
>detecting whether some one had a radio in their car.  
> 
From my rather rusty knowledge of radio, most radio receivers use a superhet 
circuit, so that the incoming signal is mixed with a local oscillator, giving 
a fixed intermediate frequency (IF) that is more easily amplified. The
detector detectors work by picking up IF re-radiated from your radar 
detector. In Britain, where one has/used to pay for a TV licence, there 
are/were TV detector vans prowling the streets, looking for people who hadn't 
paid their licence fee. They had a couple of long solenoid antennae on the
roof, and I believe could triangulate an operating TV from the IF. 

I wonder how much of the IF is radiated back from the detector antenna, and 
how much from the rest of the module. It might be worth putting the detector 
in a proper RF shielded enclosure.

--
 Andrew Daviel, Vancouver, Canada <advax@triumf.ca>
  finger advax@reg.triumf.ca for PGP key

Newsgroup: sci.electronics
document_id: 52829
From: mark@wdc.sps.mot.com (Mark Shaw)
Subject: Re: Rumors

In article <1993Apr2.174851.22659@cs.unca.edu>, kepley@photon.phys.unca.edu (Brad Kepley) writes:
|> I just heard an unbelievable rumor that Motorola has decided to drop their
|> integrated circuit manufacture business.  Apparently a Digikey rep called 
|> one of our production coordinators, for out information so that we could
|> make plans to deal with this, that Moto was getting out.  Anybody else
|> get a call about this?
|> 
|> Too much for me.  It's about like Intel announcing they were getting out
|> of the IC business.


This rumor didn't happen to appear on April 1st?

If this DigiKey rep was serious, I think I will buy my parts elsewhere.
If that is the way they do business, you cannot trust them.

Mark

Newsgroup: sci.electronics
document_id: 52830
From: Joseph N Hosteny <jh8e+@andrew.cmu.edu>
Subject: Re: Electric power line "balls"


    Do you know if there is an airport nearby? They may just be markers
to tell pilots of small planes that there are power lines nearby.

/Joe

Newsgroup: sci.electronics
document_id: 52831
From: ubsiler@msuvx1.memst.edu
Subject: Home-made IR remote extender

Here's a question for all you electrical engineers out there:

  I bought an 'Infrared detector module' at Radio Shack for $3.95 - it is a 
little gizmo that senses infrared remotes and produces an output signal. Then
I hooked the output through a transistor to an infrared LED. The circuit works
like a minature remote control extender in my car - All remote commands are
relayed to the CD player hidden in the glove compartment. It works fine with
my Denon CD player, but when I tried to build the same circuit for a friend's
VCR, it didn't work.
  The circuit appears to work for other remotes (you can see infrared with a
Sony CCD camcorder) but coincidentally it only seems to work for my CD
player...

	Any advice would be appreciated....
        Brian

---
UBSILER @ MSUVX1.MEMST.EDU


Newsgroup: sci.electronics
document_id: 53128
From: et@teal.csn.org (Eric H. Taylor)
Subject: Holes: practical questions, was - Philosophical Question

In article <12426@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>[...]
>I agree.  I come at this from nuclear physics, where one often discusses 
>particle-hole excitations and certain reactions have the effect of 
>applying an annihilation operator and creating a hole, and it is a 
>subtle question.  The longer one works with them, the more real they 
>become.  There are also quasi-particles, which raise the same sort 
>of question about how "real" the entity is.  The phenomenon is most 
>certainly a real one. 

OK, I've asked this before, and with a new thread on these lines, I
ask this again:

1: If a large hole current is run thru a resistor, will there be
   I^2 * R cooling instead of heating?

2: Can anyone design an amplifier that preferentially amplifies
   hole currents over normal electron currents?

3: what semiconductor materials have the highest ratio of
   hole mobility to electron mobility? (please quote actual
   test samples rather than estimates based on theory. Also,
   don't be limited to semiconductors: consider also insulators,
   resistors, dielectrics, piezo-electrics, conductors,
   magnets (metal, ceramic), magnetostrictives, etc).

NOTES:

   to summarize, this thread has so far stated that the only area
   where holes are not detectable is the vacuum. That is, hole
   particles only exist in the presence of matter.
   Previous threads have stated that holes only exist in certain
   semi-conductors. The question that naturally arises is if
   the hole currents inside a semi-conductor vanish at the point
   where the semiconductor is joined to a conductor (say, copper).
   I don't want a theoretical discussion here about whether
   holes could exist inside metal conductors, rather I ask for
   an experimental discussion on how to amplify and detect such
   currents *if* they exist.
   Also note that I have cross-posted this to sci.electronics
   since this is now becoming an electronic discussion.

Thanx,
Eric.

----
 ET   "A Force of Nature"
----

Newsgroup: sci.electronics
document_id: 53502
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Need tone decoder circuit

In article <5170286@hplsla.hp.com> tomb@hplsla.hp.com (Tom Bruhns) writes:
>>Does anybody out there have a circuit that will decode a 1000Hz tone?
>
>Use a NE567 tone decoder PLL chip...

My impression -- it's not an area I've played with much -- is that the
much-beloved NE567 is basically obsolete.  If you want to detect a 1kHz
tone, set a switched-capacitor filter chip to that frequency, feed your
input to it, and see if anything comes out the other end.  The NE567 was
what you used when good clean bandpass filters were hard to do; nowadays
they're easy, and the results are better.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53503
From: heuvel@neptune.iex.com (Ted Van Den Heuvel)
Subject: Motorola MC143150 and MC143120 


Does anyone out there know of any products using Motorola's Neuron(r) chips MC143150 or MC143120. If so, what are they and are they utilizing Standard Network Variable Types (SNVT)?
_________________________________________________________________________________

Ted Van Den Heuvel   heuvel@neptune.iex.com
KX5P

Newsgroup: sci.electronics
document_id: 53504
From: rich1@netcom.com (Richard Soennichsen)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

The Bmw speedo is triggered by a reed switch\magnet assembly in the differential. I would think that this signal would be easy to reproduce.

Newsgroup: sci.electronics
document_id: 53505
From: obrien@hri.com (Jim Obrien)
Subject: IBM-PC XT switch settings

I just got an IBM-PC XT with no documents. Its a true
IBM, and I was wondering if anyone had the definitions
of the 2 8 position dip switches? 

- thankx Jim



Newsgroup: sci.electronics
document_id: 53506
From: bell@hops.larc.nasa.gov (John Bell)
Subject: Re: Adcom cheap products?

In article <mdonahue.15x9@amiganet.chi.il.us> mdonahue@amiganet.chi.il.us (Mike Donahue) writes:
>
>As for Adcoms Mobil, They are going with amps that canb use Balanced Inputs, a
>VERY nice toy, but I'm afraid its goig to push their amps beyound resonable
>price ranges.  especialy because taking advantage of those balanced inputs
>requires a $120+ RCA to Balanced adapter...

Umm, when I was doing sound reinforcement for a living, I used to get direct boxes (which convert
unbalanced 1/4" jacks to balanced XLRs) for about $25 each, or a little more for higher
quality. You'll need two for a stereo signal, of course, and a little adapter thingy from 
Radio Sh#$&^t to convert from RCA to 1/4". Total cost should be around $50. You can also buy
transformers for quite a bit less and wire them yourself. Total cost there should be under $30.
You can get all this stuff from any pro music shop that sells sound reinforcement gear.
The benefit? NO noise that you can hear will be generated in the cables going to the component
with the balanced inputs, even when you run them in bad places, like next to power lines.

-----
John Bell
NASA Langley Research Center
bell@hops.larc.nasa.gov


Newsgroup: sci.electronics
document_id: 53507
From: moffatt@bnr.ca (John Thomson)
Subject: Re: Telephone on hook/off hok ok circuit 

Tony Kidson (tony@morgan.demon.co.uk) wrote:
: In article <oHZs2B2w164w@k5qwb.lonestar.org> lrk@k5qwb.lonestar.org writes:
: 
: >mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
: >
: >> In article <1ptolq$p7e@werple.apana.org.au> petert@zikzak.apana.org.au (Peter
: >> >
: >> >Just a thought of mine here:
: >> >Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 1
: >> >How about an LED in series with a zener say around 30V.
: >> >On-hook = LED on
: >> >Off-hook = LED off.
: >> >Would this work? If anyone tries/tried it, please let me know.
: >>
: >> Aye, there's the rub -- if you draw enough current to light an LED, the
: >> equipment at the phone company will think you've gone off hook.
: >> In the on-hook state you're not supposed to draw current.
: >
: >Which means you should just use your Digital VoltMeter. You can use an
: >old VOM but the phone company equipment can detect that and might think
: >there's something wrong with the cable.
: >
: 
: Look Guys, what's the problem here?  If you want a light that goes on when 
: the 'phone is *Off* hook, all you need it to run it in *series* with the 
: line, as I mentioned in my previous post.  If you want a light that goes on 
: when the 'phone is *on* hook, all you need is a voltage threshold detector.

If you're going to do the series Diode thing (which is the easiest), just
make sure that the LED can take the current (I can't recall it off-hand, but
it's something like 100mA or more?)

Greggo.

Greg Moffatt  moffatt@bnr.ca
Bell-Northern Resarch Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
document_id: 53508
From: dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz)
Subject: Dumb Question: Function Generator


	I have a new scope and I thought I'd save a few bucks by
buying one with a function generator built in. After having it awhile
I noticed two things about the function generator. For one, there
seems to be a bias even when the 'pull-offset' is pushed in. That is,
I have to pull that know and adjust it to get a signal sans some
random 50mV bias.
	The other _really_ annoying thing is that the damn output
won't go below about 1V p-p. I am a student ( you may have guessed
from my previous posts ), and I often have to measure the input
impedances of various circuits I build.Many of the circuits have
maximum input signals of way less than 500mV amplitude and most have
input impedances in the 10's of Kohm range. The thing is, in order to
use my function generator I have to divide the voltage to some thing
reasonable. Then, of course, to measurethe input impedance of my
circuit I am going to have to throw in another resistor in series.
With the 50ohm output of the generator I could just ignore it, but now
with this little divider there I have to figure that in. It's kind of
a pain in  the ass.
	Is there any way I could make myself a little box that could
solve this little problem. The box would tkae the function generator
input, lower the voltage and give an output impedance that is some
low, unchanging number. I would want to lower the voltage by a factor
of one hundred or so. I could just build a little buffer amp, but I'd
like to have this box not be active.
	Any quick ideas. The scope's not broken. For other reasons I
had sent it to the shop to get repaired and they replaced it. The
function generator was the same way on that one, too.

			please help as I am feeling very stupid 
			today,

						dave 
						dgj2y@virginia.edu


Newsgroup: sci.electronics
document_id: 53509
From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
Subject: Can I use a CD4052 analog multiplexer for digital signals?

As the subject says - Can I use a 4052 for digital signals?  I don't see
why it couldn't handle digital signals, but I could be wrong.  Anyone have
any advice?  Thanks.


 _I_______________________________________________________________________I_
(_@_)                                                                   (_@_)
|   |   Raymond Yeung               Internet: Nimbus@uiuc.edu           |   |
|   |                                         rky57514@uxa.cso.uiuc.edu |   |
|   |   EE student at the                                               |   |
|   |   University of Illinois    CompuServe: 70700,1011                |   |
|   |   at Urbana-Champaign                                             |   |
(___)-------------------------------------------------------------------(___)
  I                                                                       I

Newsgroup: sci.electronics
document_id: 53510
From: sciamanda@edinboro.edu
Subject: Re: Emergency Vehicle Sensors?  traffic-light-phreaks?

In article <LINNIG.93Apr7154239@m2000.dseg.ti.com>, linnig@m2000.dseg.ti.com (Mike Linnig) writes:
> Folks,
> 
> Here in the Dallas area I have noticed that it is quite common to see an odd
> "sensor" on top of traffic lights.  These have been here for at least six
> years.  I've often wondered what they are.
> . . . 
> Mike Linnig, Texas Instruments Inc. | 97.43% of all statistics are made |
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Here in Erie, PA there is a system in the inner city called Rado-Lite (a 
trade name) which allows police and ambulance vehicles to gain right of 
way by controlling traffic lights through RADIO signals.  The receivers 
look much like what you describe, but they include a UHF whip antenna (less
than a foot tall) and a light which flashes on and off to let traffic know that 
an emergency vehicle has taken control and is approaching.  Local folklore 
says this system was invented here; I don't know if this company has any 
other installations.  It has been in operation for at least 30 years, going 
only by my memory.

Bob Sciamanda
Edinboro Univ of PA

Newsgroup: sci.electronics
document_id: 53511
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: FAQ - corrections


	Greetings. I received a reply stating that unless someone else
	confirms that the following company is operating, I should
	remove it from my lst:

>PCB Prototypes of Sandy, UT
>Ronald Baker
>8195 South 2660 East
>Sandy, UT  84093
>Tel: [read below]
	
	This is from the COMM_PCB.FAQ (commercial PCB makers).

	Also, I don't have time to get the FAQ onto the sci.answers
	because of what I like to refer to is "red tape" - after the
	finals, I'll see what I can do... in the mean-time, anyone know
	of an FTP site that wouldn't mind a 250K file? :-)

	And last, I have some new entries for the SIMUSOFT list (mostly
	commercial/institutional stuff) but was wondering: should I keep
	the restrictions on the price of the software to be considered ->
	under $600 or should I include all those in 4 digit prices also?

	Take care.
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
document_id: 53512
From: cab@col.hp.com (Chris Best)
Subject: Re: Illusion

> This is not a new idea.  At least 10 years ago I got this little gadget with
> a keyboard on the back and 8 LED's in a vertical row on the front.  It has a
> long handle and when you wave it in the air it "writes" the message you typed
> on the keyboard in the air. 

----------

This is not news.  In fact it's where I got the idea from, since it was
such a neat item.  Mattell made it, I believe, modeled after a "space 
saber" or "light sword" or something likewise theme-y.  My addition was 
using a motor for continuous display, and polar effects in addition to 
character graphics.  I should have protected it when I had the chance.  
No one to kick but myself...

Ten years ago is about right, since I built mine in '84 or '85.

Newsgroup: sci.electronics
document_id: 53513
From: cab@col.hp.com (Chris Best)
Subject: Re: Need help with car stereo....

Just a shot here, but ya never know:

I once bought a (REAL) cheap equalizer / power amp for my car tape player 
at one of those motel-room truckload sales, and it sounded great.  For a 
while, that is.  Then one channel quit entirely.  I opened it up, and the 
amplifier chip for the bad channel had simply melted some of its solder 
joints attaching it to the PCB.  I soldered them back and it worked fine.  
I just had to keep the volume a bit lower than I did before.  Probably 
lousy heat sinking.

You said "a nice Alpine" which I'm sure is a few orders of mag higher
in quality than the P.O.S. I had.  But the point is - look inside before
you scrap it, since you OCCASIONALLY find something you can repair.
Maybe even the same thing I found.

Good luck!

Newsgroup: sci.electronics
document_id: 53514
From: cab@col.hp.com (Chris Best)
Subject: Re: Uninterruptible Power Supply

I'm no expert at UPS's, but you said something that made it sound like
you didn't realize something.  On a typical UPS (well, on ours, anyway),
there is NO switchover from AC to DC.  All the protected equipment is
ALWAYS running from the batteries (via an inverter), with the usual 
condition of also having them on charge.  If the power fails, big deal - 
the computers never see it (until the batteries start to droop, but 
there's something like 60 car-sized batteries in that cabinet, so it 
takes a while).

If you were gonna run the guts on straight DC instead of an inverter,
why not do it all the time?  Then there'd be no switchover to screw
things up, and no having to sense the failure fast.  Just keep the DC
on charge when the power is on, and it'll be there in zero time when
you "need" it.

Just some ideas.  Can't guarantee what'll work or not, but hope at least
SOME of this helped.

Newsgroup: sci.electronics
document_id: 53515
From: prasad@vtaix.cc.vt.edu (Prasad Ramakrishna)
Subject: Exploding TV!

I had a GE Emerson 13" color TV for about 3 years and one fine day,
while we were watching something (I doubt if the program was the cause),
we heard a mild explosion.   Our screen went blank but there was sound,
so we thought, 'oh we have special effects on the program'.  But soon
the sound stopped and smoke started to appear at the back of the TV.
The brilliant EEs we are, we unplugged the TV and called customer service
only to be thrown around by please hold, I will transfer u to blah blah..
  Finally we abandoned the idea of trying to fix the TV and got a new one
(we wanted a bigger one too!).
 After all the story, what I wanted to know is: Is my problem an isolated
incident or a common one? (I recall reading about Russian TVs exploding, but
not here, in the US). Why would the picture tube explode or even smoke?
 I still have the left over TV set, I might dig into it this summer. Any
idea where I can get parts for these things? (probably will cost more than TV).

W/my 0.02
Prasad
prasadr@vtvm1.cc.vt.edu


Newsgroup: sci.electronics
document_id: 53516
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates
From: sldf3@sol.ee.usu.edu (Weston R Beal)

In article <C5Hs5J.AG7@bcstec.ca.boeing.com>, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:

|> It seems reasonable to me that a microwave transmitter-receiver setup could 
|> do the job. For example, say you want to map an acre lot, it'd be convenient
|> to place MW transmitters around the lot's periphery (either 2 or 3) and then
|> carry a hand-held recorder and walk to a point on the lot, press a button and
|> the coords of the recorder's location is stored as digital data.
|> 
|> What's the chance of this working? Any systems like this already exist?
|> What kind of accuracy could you expect? What would something like this
|> cost to prototype? Is there a better alternative than microwaves?

Of course you could develope this system, but there is already a system called Global
Positioning Satellites.  It gives three dimensional coordinates anywhere on earth. 
Many surveyors use this system with a differential receiver/transmitter to get
coordinates within centimeters.  Basic receivers with resolution of a few meters (on
a good day) are available from many sources.


-- 
WMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMW

  \_      \_  \_\_\_    \_\_\_               Weston R Beal
   \_      \_  \_    \_  \_    \_         sldf3@sol.ee.usu.edu
    \_  \_  \_  \_\_\_    \_\_\_            sldf3@cc.usu.edu
     \_\_  \_\_  \_  \_    \_    \_       Electrical Engineer
      \_      \_  \_    \_  \_\_\_       Utah State University

  "That's the wonderful thing about crayons; they can take you to
   more places than a starship can."    - Guinon



Newsgroup: sci.electronics
document_id: 53517
From: carlos@math.lsa.umich.edu (Carlos Montenegro)
Subject: Low voltage lighting and X10 questions.

1. Can low Voltage lights be controlled with an X10  module by putting it 
before the transformer? It seems to work, even the dimmer works. Not very 
reliable. Will it damage the module? Can it be done reliably?

2. I put a motion switch (Heath) to a low voltage light, it worked but now it is
broken, too much current? How can I get arround that? 
  
3. How can I increase the intensity of a light using the X10 PC computer
interface without having it go 100% on first and then down. I am doing
my own programing, not the X10 program.

Thanks   C. Montenegro 

Newsgroup: sci.electronics
document_id: 53518
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Dumb Question: Function Generator

In article <C5J845.3B8@murdoch.acc.Virginia.EDU> dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
>
>	I have a new scope and I thought I'd save a few bucks by
>buying one with a function generator built in.

Hmm... now where was that ad for the combination radio/hand cranked
generator/flashlight/siren I saw? :-)

[function generator has a 50mV offset, and the amplitude's too high]

>	Is there any way I could make myself a little box that could
>solve this little problem. The box would tkae the function generator
>input, lower the voltage and give an output impedance that is some
>low, unchanging number. I would want to lower the voltage by a factor
>of one hundred or so. I could just build a little buffer amp, but I'd
>like to have this box not be active.

Sure, you've already got the right idea.

Ignoring the 50 ohm internal resistance of the generator for a second, just
run it into, say, a voltage divider made of 990 ohms in series with 10
ohms.  This new circuit is the Thevenin equivalent of one that puts out
1/100 of the original voltage, and has an output impedence of negligibly
less than 10 ohms.  You may want to monkey with the values a little
depending on whether you care more about the _exact_ dividing ratio or
the availability of parts.

Hows that sound?

					---Joel Kolstad

P.S. -- This is why those 1000:1 high voltage probes for multimeters can be
accurate but still cheap.  They have something like 100 megs in series with
100k, which doesn't load the (often high impedence) source much, as well as
keeping the (probably 10 meg impedance) multimeter happy.

Newsgroup: sci.electronics
document_id: 53519
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: what to do with old 256k SIMMs?

In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
|> >	I was wondering if people had any good uses for old
|> >256k SIMMs.  I have a bunch of them for the Apple Mac
|> >and I know lots of other people do to.  I have tried to
|> >sell them but have gotten NO interest.

We use them as Christmas tree decorations, the cat doesn't eat these.

-- 

	...Wex

Newsgroup: sci.electronics
document_id: 53520
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: A question about 120VAC outlet wiring.. (the truth)

I suggest that misc.consumer.house is a better forum for this, several
electricians, a huge FAQ that adresses ALL the issues raised here.

-- 

	...Wex

Newsgroup: sci.electronics
document_id: 53521
From: lancer@oconnor.WPI.EDU (Stephe Lewis Foskett)
Subject: How do DI boxes work?


I'm doing sound for a couple of bands around here and we need Direct
Input boxes for the keyboards.  These are the little boxes that take a
line level out of the keyboard and transform it into low-Z for the run
to the mixer.  Sadly they cost like $50 (or more) each and I'm going
to need like 5 or 10 of them!  I looked inside one (belonging to
another band) and it looks like just a transformer.  Does anyone have
any plans for building them?  Perhaps in Anderton's "Electronic
Projects for Musicians" book (which I am having a hell of a time
tracking down...)?

Thanks a lot!

.s.

PS: Post or email.  I read this group...
--
- lancer@wpi.wpi.edu -                    - 0{{  MoDiMiDoFrSaSo: -
-   Mein Kopf ist ein Labyrinth, mein Leben ist ein Minenfeld    -

Newsgroup: sci.electronics
document_id: 53522
From: msf@skaro.as.arizona.edu (Michael Fulbright)
Subject: Re: Analog switches/Balanced Demodulators

caadams@atlas.cs.upei.ca (Kenny Adams) writes:

>hi,
>	instead of using a +15vdc supply for the 4066 try using a +7 and -7
>volt supply.  i have some commercial audio equipment that uses this approach
>for ground referenced audio.  they use the -7 volt supply as the logic
>ground.

In this case would the switch control voltages be -7V to turn the switch
off and >0V to turn the switch on?

michael fulbright
msf@as.arizona.edu

Newsgroup: sci.electronics
document_id: 53523
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: A question about 120VAC outlet wiring..

In article <1qids1INNebl@chnews.intel.com> crichmon@sedona.intel.com (Chris Richmond) writes:
>
>In article <1993Apr14.193122.20818@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>> In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:

>> |> I'm considering modernizing some old wiring in my home, and
>> |> I need a little advice on outlet wiring.  Several outlets
>> |> are the old 'two prong' type, without the ground.  Naturally,
>> |> the wire feeding these outlets is 12/2, WITHOUT the ground
>> |> wire.  I noticed at the fusebox that some circuits have the
>> |> 12/2 with ground, and that on these circuits, the ground
>> |> wire was tied to the same bus as the neutral (white) wire.

>> This is contrary to the electrical code and should be fixed.

>Well, my house was built just last year, and the breaker box is wired the
>same way.  

	There SHOULD be a connection of the GROUND wire to a ground
in the breaker box.  There also should be a connection of the NEUTRAL
wire to a ground in the breaker box.  There should be no other 
place in the building where such a connection occurs (i.e. not in
any of the outlet boxes).

	The NEUTRAL (white) wire is a 'grounding conductor' for
the plug, and is NOT safe to touch, while the GROUND (green)
wire is a 'protective ground' and carries no current unless
some kind of electrical fault has occurred.  It's safe
to touch the protective ground, but not to touch the 
grounding conductor (because there is current in the grounding
conductor, its outlet-box end will not be at the same ground
potential as its breaker-box end).

	John Whitmore

Newsgroup: sci.electronics
document_id: 53524
From: bill@thd.tv.tek.com (William K. McFadden)
Subject: Re: Cable TVI interference

In article <VL812B2w165w@inqmind.bison.mb.ca> jim@inqmind.bison.mb.ca (jim jaworski) writes:
>What happens when DVC (Digital Videon Compression) is introduced next 
>year and instead of just receiving squiggly lines on 2 or 3 channels 
>we'll be receiving sqigglies on, let's see 3*10 = 30 channels eventually.

Since the digital transmission schemes include error correction and
concealment, the performance remains about the same down to a very low
carrier-to-noise ratio, below which it degrades very quickly.  Hence,
digitally compressed TV is supposed to be less susceptible to interference
than amplitude modulated TV.

-- 
Bill McFadden    Tektronix, Inc.  P.O. Box 500  MS 58-639  Beaverton, OR  97077
bill@tv.tv.tek.com, ...!tektronix!tv.tv.tek.com!bill      Phone: (503) 627-6920
How can I prove I am not crazy to people who are?

Newsgroup: sci.electronics
document_id: 53525
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Where to buy parts 1 or 2 at a time?

The pricing of parts reminds me of something a chemist once said to me:

"A gram of this dye costs a dollar.
It comes out of a liter jar which also costs a dollar.
And if you want a whole barrel of it, that also costs a dollar."

I.e., they charge you almost exclusively for packaging it and delivering
it to you -- the chemical itself (in that particular case) was a byproduct
that cost almost nothing intrinsically.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53526
From: wellison@kuhub.cc.ukans.edu
Subject: Re: electronic odometers

I had the insturment panel go out in my car (a 1990 Lincoln Contenintal) which
is a digital dash. They replaced the whole thing with a 1991 dash (thank god it
was under the warrenty ! :-) Anyway, the odometer was reading the exact milage
from the old panel. It must have a EEPROM of some sort in it that is up-dated.
Seems to me that removing the battery would erase it, but it doesn't. So I
guess they swapped the NVM chip (non-volitile memory) and installed it in the
new dash. No, they wouldn't let me have the old dash to tinker with :-(


-=-= Wes =-=-

Newsgroup: sci.electronics
document_id: 53527
From: harry@neuron6.jpl.nasa.gov (Harry Langenbacher)
Subject: Re: Uninterruptible Power Supply

In article <NURDEN1.25.734866568@elaine.ee.und.ac.za> NURDEN1@elaine.ee.und.ac.za (Dale Nurden) writes:
>I'm wanting to build a simple UPS for my PC. ... sustain the computer long enough to complete 
>the current task and save, 5 to 10 minutes should be enough....
>I think, though I don't really need to keep the monitor active (I can try to 
>remember what to do) so maybe I can avoid a DC-AC inverter and just use a 
>battery to directly supply the motherboard and peripherals.

Now there's a good idea ! All you need is 20 amps DC for a few minutes, and
a good (wetware) memory (was I using wp or autocad or ...). I thought of the
same idea myself a few days ago. I've got a fairly new car battery that I take
along in my 4x4 when I go camping, and it sits around useless when I'm home.
I wish I could get a batteryless ups to use it with, or use it with a heavy
duty 5-volt regulator to supply the PC. But I guess you'd need -5v and -12v 
(and +12) too (2 more batteries ?).

An alternative would be to leave a 40 AMP battery charger hooked up to the battery
and run a 12vdc to 110vac converter running all the time, and when the power
goes out, voi-la ! the 110vac converter keeps on running off the battery ! and
then I could take the 110vac converter and my computer on the camping trips !-)


-- 
Harry Langenbacher 818-354-9513 harry%neuron6@jpl-mil.jpl.nasa.gov
FAX 818-393-4540, Concurrent Processing Devices Group, Jet Propulsion
Laboratory, M/S 302-231, 4800 Oak Grove Dr, Pasadena CA 91109 USA

Newsgroup: sci.electronics
document_id: 53528
From: ali@cns.nyu.edu (Alan Macaluso)
Subject: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.


---
A l a n  M a c a l u s o		 	PURPLE MOON GIANTS
ali@cns.nyu.edu  				158 E. 7th. St. #B5
(212) 998-7837					NYC  10009
						(212) 982-6630

		
	        

Newsgroup: sci.electronics
document_id: 53529
From: alung@megatest.com (Aaron Lung)
Subject: Re: what to do with old 256k SIMMs?

In article <1993Apr15.100452.16793@csx.cciw.ca> u009@csx.cciw.ca (G. Stewart Beal) writes:
>In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>>
>>	I was wondering if people had any good uses for old
>>256k SIMMs.  I have a bunch of them for the Apple Mac
>>and I know lots of other people do to.  I have tried to
>>sell them but have gotten NO interest.
>>
>>	So, if you have an inovative use (or want to buy
>>some SIMMs  8-) ), I would be very interested in hearing
>>about it.
>>
>One of the guys at work takes 20 of them, uses cyano-acrylate glue to make
>five four-wide "panels" then constructs a box, with bottom, to use as a
>pencil holder.
>

Or, if you've got some entreprenuerial (sp?) spirit, get a cheapy
clear plastic box, mount the simm inside, and sell it as a 'Pet SIMM'!

I'm sure there are *plenty* of suckers out there who would go
for it!

aaron



Newsgroup: sci.electronics
document_id: 53530
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: A question about 120VAC outlet wiring..

olsen@vetmed.cvm.uiuc.edu (Aart_Olsen) writes:

>>|> I noticed at the fusebox that some circuits have the
>>|> 12/2 with ground, and that on these circuits, the ground
>>|> wire was tied to the same bus as the neutral (white) wire.
>>
>>This is contrary to the electrical code and should be fixed.
>>
>Sorry, but this is exactly according to the NEC.

No need to be sorry, I blew it on this one.  At the main breaker box
where there is a thick wire ground leading to the earth, both neutral
and ground are hooked to this bus.  In any other breaker box (or an
outlet box, etc.) the ground and neutral must not be connected together.



Newsgroup: sci.electronics
document_id: 53531
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: mysterious TV problem -- source?

LLBGB@utxdp.dp.utexas.edu writes:
>Initial symptoms:
>-no picture or sound
>-CRT filament does NOT glow
>-flyback ticking as described abovew

>Discovered when hooked up the scope:
>-IF strip is not putting out audio or video signals
>-everything is making simple 20-30 Hz pulses
>-horiz out transistor collector (case of the TO-3) is a 20-30 Hz downgoing
>  sawtooth with ca. 15kHz ring at front end

>guys, WHAT"S GOING ON HERE?  Anyone seen this before?

What is happening is this:
1) You turn the TV on.
2) The horizontal output begins normal operation.  This powers up the
   high voltage and most of the rest of the circuitry.
3) A problem is sensed and the horizontal oscillator shuts down.
4) After it powers down the cycle repeats.

Things to check:
First check for a shorted high power component.  Your best bet is the vertical
output transistor(s) or, if there is one, the voltage regulator.  The most
common cause of this type of failure is too much current being drawn
somewhere.
Also look for shutdown circuits (which your TV may or may not have),
if you can find one that is shutting down the horizontal oscillator
then it shouldn't be too hard to find the problem from there.


Newsgroup: sci.electronics
document_id: 53532
From: alung@megatest.com (Aaron Lung)
Subject: Re: What are some good Suppliers of Chips?

In article <1qihcl$9ri@usenet.INS.CWRU.Edu> ae454@cleveland.Freenet.Edu (Paul Simundza) writes:
>
>
>anyone know of any good supplier's of chips, one that could have almost
>any chip i need? I don't want to hunt down all the chips I may need so
>it would be greatly appreciated if anyone knows of a good distributor
>..
>thankyou
>

Paul,

Unfortunately, there are not too many retail outlets that'll stock
just about every chip made.  The stuff they will stock are the ones
that'll sell, like standard DRAM's, 80386's, 68000's, etc,etc.
i.e.  I cna't think of any 'one-stop-shopping' store.

The closest you can get is to pick up a copy of Byte magazine or
the Circuit Cellar, Popular Electronics, and the like and flip
through them.

Distributors like Wyle Electronics, Hamilton Avnet, Pioneer Electronics,
etc, etc, don't normally deal with end-users like ourselves where
we only a couple of everything...they only deal with people who buy
by the hundreds or more.  Each distributor represents and sells a variety of
different non-competing manufacturers.  What do I mean by this?
Suppose ABC Electronics sells Intel 80386's.  It's a pretty good
bet that they won't be selling any of AMD's 386's, or vice-versa.
They also can obtain just about *any* chip you want from a manufacturer
they represent.

Who knows?  You might be lucky to be able to buy from one of them.
But I'd be suprised if you do.  ALso bear in mind that the 1 or 2
qty prices they will charge you will be *much* greater than what
a mail order outlet will charge.

My advice?  If you're gonna be designing anything, try to stick
with off-the-shelf stuff.  You're going to get stuck if you use
too many esoteric parts sooner or later.

good luck,

aaron


Newsgroup: sci.electronics
document_id: 53533
From: adler@netcom.com (Bruce Adler)
Subject: Re: IBM-PC XT switch settings

In article <1qk158$kcp@bigbird.hri.com> obrien@bigbird.hri.com writes:
>I just got an IBM-PC XT with no documents. Its a true
>IBM, and I was wondering if anyone had the definitions
>of the 2 8 position dip switches? 

SW8,SW7	number of 5.25" drives
0,0	1 drive
0,1	2 drives
1,0	3 drives
1,1	4 drives

SW6,SW5	type of display
0,0	reserved
0,1	40x25 color (mono mode)
1,0	80x25 color (mono mode)
1,1	mono 80x25

SW4,SW3	amount of memory on system board
	64k chips	256k chips
0,0	64k		256k
0,1	128k		512k
1,0	192k		576k
1,1	256k		640k

SW2	co-processor installed
SW1	loop on POST

Newsgroup: sci.electronics
document_id: 53534
From: tsp@ccd.harris.com (Timothy S. Pillsbury)
Subject: need ACS tutorial and/or netlist examples


I recently ftp'd Al's Circuit Simulator (ACS) and I'm looking for
the tutorial which is mentioned in the Users Manual (but not found there).
I don't have any experience constructing a netlist (such as for SPICE)
and I need a little help.

The examples which come with ACS aren't explanatory about the translation
between schematic and netlist. Does anyone have the fabled "Tutorial"
or any other reference which could help me in constructing a netlist from
a schematic diagram?

(I also emailed Al himself but received no response yet. He's probably
 busy with his next release.)
-- 
-------------------------------------------------------------------------------
Tim Pillsbury          Internet:  tsp@ccd.harris.com
                          uunet:  uunet!ccd.harris.com!timothy.pillsbury
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53535
From: surfer@world.std.com (Internet Surfer)
Subject: New mailserver...soon...utopia-service

For all those who are interested and would like to discuss the popular
Secret Life..and/or other technical documentaries.. Please email me
as i am starting a newsgroup


-- 
jolt@gnu.ai.mit.edu	      |    Its not impossible, just improbable
johnp@pro.angmar.uucp         |            (Zaphod Beeblbrox)
bl298@cleveland.freenet.edu   |   N1NIG@amsat.org (Being a Ham is so grand)

Newsgroup: sci.electronics
document_id: 53536
From: ardai@wizard.atb.teradyne.com (Michael Ardai)
Subject: Re: Source for carbide pc board drills?

In article <C5EJL7.LIn@news2.cis.umn.edu> Mike Diack <mike-d@staff.tc.umn.edu> writes:
-In article <C5DGG7.5ox@wang.com> , pvr@wang.com writes:
->   Who sells the special carbide drills used to drill pc boards?
->I am looking for sizes smaller than #60, #65 or #70 would be good.

-best deal i ever saw on carbides was at ELI electronics - Cambridge
-Mass. Quite close to MIT, #70 drills @ $5.00 for a box of 50. ELI are
-in the Boston fone book.

Actually, I think they are all #57.  Their phone number is 617 547 5005
and I will probably have some over at the MIT Flea this Sunday.
/mike


-- 
\|/     Michael L. Ardai     N1IST             Teradyne ATG Boston
--- -------------------------------------------------------------------------
/|\                    ardai@maven.dnet.teradyne.com

Newsgroup: sci.electronics
document_id: 53537
From: cph@dmu.ac.uk (Chris Hand)
Subject: Cheap LCD panels & seeking info

Attention hardware hackers and bargain seekers!

I just bought a 640x200 pixel LCD panel for 25 UK pounds.  I have
a datasheet for a similar panel, but I'm looking for proper data.

If anyone can help with locating data for this device (before I start
with the routine on the phone to Hitachi and rummaging through the
library), then I'll pass on the source.

	Type: LM225 (Hitachi)
	Resolution: 640W x 200H (so can do 80x25 chars on 8x8 matrix)

Bought from:

	Greenweld Electronics Ltd
	27 Park Rd
	Southampton SO1 3TB, UK

	Tel. +44 703 23 63 63
	Fax. +44 703 23 63 07
	Email: Compuserve [100014,1463]

NB: I only just bought this!  I don't even know if it works!

	Price was 25 UK pounds including VAT (17.5%), which isn't
	payable if you're outside the EC.

Thanks for any info!


Chris

-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
document_id: 53538
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: R/S Battery of the Month Club

In article <JWATERMA.93Apr14214858@jade.tufts.edu> jwaterma@jade.tufts.edu (Jason Waterman) writes:
>I talked to a friend who works for Radio Shack, and he said the deal
>with the Red Batteries were that they had too much lead in them.
>Condidering the Red Batteries had a life cycle shorter than a mayflies, 
>I think the EPA was worried about all those batteries being dumped out.

Pardon me, but why would carbon-zinc cells have any lead in them at all.
--scott


Newsgroup: sci.electronics
document_id: 53539
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Do Analog Systems Need Ground Planes?

engp2254@nusunix1.nus.sg (SOH KAM YUNG) writes:

>I understand the need for a ground plane in a digital system. However, I
>would like to know if such a ground plane is also necessary in an analog
>system.
>
>(Note: this ground plane will not be connected, except at one point, to
>the signal ground).
>
>I keep getting conflicting answers over this. Does having a ground plane
>in an analog system help reduce noise also? My system only deals with
>low frequency signals (up to 100Hz only!!!).

Well, one reason for getting conflicting answers is that it depends on
what you want the ground plane to do.  A continuous conductor is a good 
electrostatic shield.  Do you have signals on your board that need
shielding rom other things?  This shielding won't do much good for magnetic
fields, unless you make it continuous around the circuit to be shielded,
like a Faraday cage.

The flip side of the coin:  if you are working with (very) high impedances,
you could end up with capacitances to the gound plane that cause problems.
You aren't likely to encounter this at 100Hz, but at 20kHz, it can be a
real problem (one that bit me once).


Newsgroup: sci.electronics
document_id: 53540
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: what to do with old 256k SIMMs?

In article <C5JCH1.FrC@ulowell.ulowell.edu> wex@cs.ulowell.edu writes:
>In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
>|> >	I was wondering if people had any good uses for old
>|> >256k SIMMs.  I have a bunch of them for the Apple Mac
>|> >and I know lots of other people do to.  I have tried to
>|> >sell them but have gotten NO interest.
>
>We use them as Christmas tree decorations, the cat doesn't eat these.

Yes, but they don't look appropriate.  I much prefer used 833 tubes on
my tree.
--scott

Newsgroup: sci.electronics
document_id: 53541
From: davidj@rahul.net (David Josephson)
Subject: Re: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

In <C5JJJ2.1tF@cmcl2.nyu.edu> ali@cns.nyu.edu (Alan Macaluso) writes:

>I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

>Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.


>---
>A l a n  M a c a l u s o		 	PURPLE MOON GIANTS
>ali@cns.nyu.edu  				158 E. 7th. St. #B5
>(212) 998-7837					NYC  10009
>						(212) 982-6630

>		


Without doing anything really tricky, the best I've seen is the
Burr-Brown INA103. Their databook shows a good application of this
chip as a phantom power mic pre.

>	        
-- 
------------------------------------------------------------------------
Josephson Engineering, San Jose California      MICROPHONES
Tel/ 408-238-6062  Fax/ 408-238-6022            INSTRUMENTATION
email:david@josephson.com  ftp info from: rahul.net /pub/davidj/

Newsgroup: sci.electronics
document_id: 53542
From: ray@ole.cdac.com (Ray Berry)
Subject: Re: $25 network

zjoc01@hou.amoco.com (Jack O. Coats) writes:

>The same folks now have out LBL (Little Big Lan) for $75.  I think you
>get it for $50 if you already own $25 Network.  LBL works with Arcnet,
>parallel ports, and serial ports in any combination for up to 250 or so
>nodes.

    LBL now offers ethernet support also, although presently it is limited
to NE1000/NE2000 style boards.  LBL owners can get an update for $8.50.
-- 
Ray Berry kb7ht ray@ole.cdac.com  rjberry@eskimo.com  73407.3152@compuserve.com

Newsgroup: sci.electronics
document_id: 53543
From: betts@netcom.com (Jonathan Betts)
Subject: Where to find CHEAP LCD displays?

Sci.E(E) netters:

I am setting out to build and market a small electronic device that 
requires an LCD display.  All of the analog electronics are working 
fine, I have ordered a PIC ICE (not vice versa) since the PICs are so 
cheap and low-power, but I am having a devil of a time finding any 
LCD displays in the 6-8 digit range that are priced as low as I need.  I 
am looking for somthing in the range of $1 in quantities of about 
1000-10,000.

Mainstream distributors like Almac cannot help me without a part 
number, or when they do look around for something in their line 
they find a $15 8-digit LCD.  Even Digikey's cheapest offering is $5 in 
quantity.

I know LCD displays like this must exist because I see whole 
calculators for sale for $4.99, meaning the retailer probably buys it 
for $3.50 and the wholesaler probably gets it for $2.50 or so.  This 
$2.50 includes assembly labor, packaging, sales, transportation, 
import duties, the case and keyboard, the PC Board, the processor 
chip, the solar cell --- and the LCD.  The LCD can't cost much.

If anyone could put me in touch with some manufacturers and/or 
distributors that handle such things I would be much obliged.

-Joe Betts
betts@netcom.com


P.S.  I have tried tearing apart several cheap consumer devices that 
have LCDs only to find that the LCDs are unlabelled.  Has anyone else 
had better luck with this strategy?

Newsgroup: sci.electronics
document_id: 53544
From: morrow@cns.ucalgary.ca (Bill Morrow)
Subject: Amplifier into CD-ROM earphone plug ?

We have a Sun CD-ROM drive which I would like to play audio CD's in.
I have an old 10 watt amplifier which works fine when connected to a
junk "Walkman" style AM/FM radio. This amp ties the common path of the
earphone connection to ground.

However, it doesn't work with my Sony Walkman cassette player, or the CD drive,
it produces of loud low-frequency tone. Obviously Sony doesn't ground
the earphone output common. Does anyone have specs on the CD drive's 
output? Will an audio transformer help? What are others using to
play there CD's in the Sun drive so that more than one can listen?

Thanks for the help.
-- 
Bill Morrow    Clinical Neurosciences, University of Calgary
e-mail: morrow@cns.ucalgary.ca voice: (403) 220-6275 fax: (403) 283-8770 
3330 Hospital Drive NW Calgary, Alberta, CANADA T2N 4N1

Newsgroup: sci.electronics
document_id: 53545
From: oxenreid@chaos.cs.umn.edu ()
Subject: Re: Radar detector DETECTORS?

In <1993Apr06.173031.9793@vdoe386.vak12ed.edu> ragee@vdoe386.vak12ed.edu (Randy Agee) writes:

>So, the questions are -
>  What do the radar detector detectors actually detect?
>  Would additional shielding/grounding/bypassing shield stray RF generated by
>  a radar detector, or is the RF actually being emitted by the detector
>  antenna?
>  Are any brands "quieter" than others?

Ok, so your a HAM.   Well, tune in 10.7Mhz or 455Khz.  These numbers sound 
like some you have herd before?   Thats right, you guessed it, they are 
common IF numbers.   Every Super-Het receiver has a local oscillator(s)
which generates an IF.  This is what your detector detector is detecting (the
local oscillator). 

Some of these have two or more local oscillator which generate more ways to
receiver you.  If you want to receiver something at say 10.525Ghz you must 
generate a local oscillator signal of 10.525Ghz - 10.7Mhz = your local osc
frequency.  This 10.7Mhz IF is then fed into a normal AGC ckt.  
The detector is keyed uppon the AGC voltage (your mileage may vary).  Since
the AGC is a negative feed back device, a positive voltage sets off a ...
I think you get the picture.


Newsgroup: sci.electronics
document_id: 53546
From: kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan)
Subject: subliminal message flashing on TV



Hi.  I was doing research on subliminal suggestion for a psychology
paper, and I read that one researcher flashed hidden messages on the
TV screen at 1/200ths of a second.  Is that possible?  I thought the
maximum rate the TV was even capable of displaying images was 1/30th
of a second.  (or 1/60th of a second for an image composed of only odd
or even scan lines)

- Rich
  kennehra@logic.camp.clarkson.edu

Newsgroup: sci.electronics
document_id: 53547
From: urbina@novax.llnl.gov
Subject: Telcom wiring question...need help


I've got two lines coming into my apartment. Two different telephone numbers.
When I ordered the second line installed, instead of bringing out another 4
wire bundle, the telco just connected up to my yellow and black wires. So I
have one line on red & green and the other on yellow & black.

Today I was monitoring the voltage on both lines. I had a voltmeter across
the red and green and read back 52 volts. I then lifted up the receiver on my
second line.(black & yellow wires) The voltage dropped to 31 volts on the first
line. (red & green wires) I repeated this experiment with the second
line(monitoring black & yellow and lifting the handset off the cradle on the
red and green line.) It also dropped to 31 volts. 

Why is this ? I thought these were separate lines.

Next I went to the 66 block and disconnected the blue and white lines coming in
from the telco cable. I then disconnected all the phones in my apartment and
went back to the 66 block and did some resistance measurements. Both lines read
open.

I'll appreciate any help on this. Is this considered normal ?

Guy Urbina

Urbina@novax.llnl.gov
 

Newsgroup: sci.electronics
document_id: 53548
From: mwtilden@math.uwaterloo.ca (Mark W. Tilden)
Subject: BEAM Robot Olympic Games next Week in Toronto.


One week to the Robot Olympic games.  Fire up the mechanoids for combat
and come on down.

Competitors please note that there has been a slight change; the registration
desk will now be in the forward building of the Science Centre rather than
in the main competing hall.  When you arrive, please go to this desk.  Those
that have pre-registered by real-mail will find badges waiting.

Is all.  See you here.


-- 
Mark Tilden: _-_-_-__--__--_      /(glitch!)  M.F.C.F Hardware Design Lab.
-_-___       |              \  /\/            U of Waterloo. Ont. Can, N2L-3G1
     |__-_-_-|               \/               (519)885-1211 ext. 2454 
"MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"

Newsgroup: sci.electronics
document_id: 53549
From: klg@mookie.mc.duke.edu (Kim Greer)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <1993Apr15.044636.29924@slcs.slb.com> dcd@se.houston.geoquest.slb.com (Dan Day) writes:
>That's scary -- if there's a way to set an arbitrary mileage figure
>into the odometer, you can't trust *any* odometer reading, even
>if you can prove that the odometer itself is the same one that
>came on the car originally.

  I was wondering if anyone can shed any light on just how it is that these
electronic odometers remember the total elapsed mileage?  What kind of
memory is stable/reliable enough, non-volatile enough and independent enough
(of outside battery power) to last say, 10 years or more, in the life of a
vehicle?  I'm amazed that anything like this could be expected to work for
this length of time (especially in light of all the gizmos I work with that
are doing good to work for 2 months without breaking down somehow).

Side question:  how about the legal ramifications of selling a used car with
a replaced odometer that starts over at 0 miles, after say 100/200/300K
actual miles.  Looks like fraud would be fairly easy - for the price of a
new odometer, you can say it has however many miles you want to tell the
buyer it has.

Thanks for any insight.


Kim Greer                       
Duke University Medical Center		 klg@orion.mc.duke.edu
Div. Nuclear Medicine  POB 3949		 voice: 919-681-5894
Durham, NC 27710  		         fax: 919-681-5636

Newsgroup: sci.electronics
document_id: 53550
From: tod@cco.caltech.edu (Tod Edward Kurt)
Subject: data pods (10248B) for HP logic analyzer (1615A)?!?

Anyone out there in netland have a spare data pod or two from an old 
1615A Hewlett Packard logic analyzer?  If you do, I'd like to buy it off
of you.  The pod's part number is 10248B.

As a side note, anyone know of any good surplus dealer or other organization
that would carry wayward logic analzer pods?

				Thanks a byte,
						Tod
							tod@cco.caltech.edu


Newsgroup: sci.electronics
document_id: 53551
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Exploding TV!

Sounds like the picture tube lost vacuum.  This would cause the filament
to ignite and could actually turn the tube from a vacuum to a pressure
vessel, followed by an explosion when the neck assembly (mostly likely
cracked to begin with) blows off.  During the whole sequence of events,
the other circuits may continue functioning, which accounts for not
losing sound.

Newsgroup: sci.electronics
document_id: 53552
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Scope questions


	Greetings. I've been seeing the word "storage" mentioned
	around oscilliscopes but I'm curious, what does it mean?

	If my life depended on it, I'd say that it's a scope that
	uses long-persistance phosphor to keep the successive
	taces on the screen for some unit of time - "store" them.
	Do I get to live?

	Also, I've been shopping for a decent, used, [old] scope
	since my Tek 514A (portable...NOT!) and my Heathkit O-1000
	are all single trace and I need more... like 2 or 3 and at
	least 50MHz (maybe 100...)

	During my shopping at hamfests etc. I've run into the 
	problem of "old scope" terminology. I can imagine what
	a "mainframe" and "plug-in" are but some things like
	the above "storage", "coax input" (Hey, where do I get a 
	probe that fits this? I had to fiddle with mine for a week 
	before I got anything resembling "a good trace" - they all
	come with BNC connectors!), "unblanking" (huh?), and, oh,
	just like my 514 manuals, MANY changes were made along the
	way to the schematic - scopes, even with IDENTICAL model 
	numbers, have different (better?) response/performance than
	others - how can I pick the better one? Does the rule of the
	higher SN the better apply?

	Take care.
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
document_id: 53553
From: s5600043@nickel.laurentian.ca
Subject: Re: CD player going wonky - advise needed !

In article <1993Apr13.150525.17978@nessie.mcc.ac.uk>, sl@nessie.mcc.ac.uk (Stuart Lea) writes:
> Hello,
> 	I've got a problem with my CD player (SONY CDP-35) in that it refuses
> to play discs - more than a minor inconvenience!  The player itself doesn't
> recognise that there is a disc in.  It's an intermitant problem, but one 
> that is becoming more frequent.
> 
> 	Is this a common problem with older CD players and, if so, what
> can be done to rectify it ?  If there is no obvious answer, how can I begin to 
> start fault finding.  To start off with, How does thet mach recognise that 
> there is a disc in in the first place ?


My experience is that the CD drawer becomes a bit loose, and the CD either skips
or can't be read.  Try seeing if all the screws that hold down the drawer
assembly are tightened properly.  Other than that, my next guess would be one of
the motors.  Hope this helps.
Dave Haans, Laurentian University, Sudbury, Ontario.

Newsgroup: sci.electronics
document_id: 53554
From: rogerw@world.std.com (Roger A Williams)
Subject: Re: Adcom cheap products?

mdonahue@amiganet.chi.il.us (Mike Donahue) writes:


>I do NOT know much about Adcom Mobil Audio products, but I DO know for a fact
>that ADCOM does NOT make its own "High End" Home Audio Equptment and that 80%+
>of it comes directly out of Tiawan...

Like most high-volume manufacturers, Adcom has most of its PC boards
assembled off-shore (in their case, mostly in the far east).  Final
assembly _and testing_ are done in East Brunswick.

The products are, and have always been, designed entirely in the US;
by their own staff and by audiophile gurus like Walter Jung.  Adcom
also tends to prefer American and European components over their
Japanese/Far East equivalents.

Off-shore assembly is one reason that Adcom is able to make products
that perform as well as those from people like Audio Research and Van
Alstine (and better than Hafler and Forte'), but at a much lower cost.

Of course, if your musical diet consists mostly of Rock, you might
prefer components from Kenwood or Pioneer...

Roger Williams		| "Most great discoveries are made
rogerw@world.std.com	|  by accident: the larger the
consulting engineer	|  funding, the longer it takes to
Middleborough, Mass.	|  have that accident."

Newsgroup: sci.electronics
document_id: 53555
From: alung@megatest.com (Aaron Lung)
Subject: Re: Telephone on hook/off hok ok circuit 

In article <1993Apr15.144826.4607@bnr.ca> moffatt@bnr.ca (John Thomson) writes:
>: >> >Just a thought of mine here:
>: >> >Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 1
>: >> >How about an LED in series with a zener say around 30V.
>: >> >On-hook = LED on
>: >> >Off-hook = LED off.
>: >> >Would this work? If anyone tries/tried it, please let me know.
>: >>
>: >> Aye, there's the rub -- if you draw enough current to light an LED, the
>: >> equipment at the phone company will think you've gone off hook.
>: >> In the on-hook state you're not supposed to draw current.
>: >
>: >Which means you should just use your Digital VoltMeter. You can use an
>: >old VOM but the phone company equipment can detect that and might think
>: >there's something wrong with the cable.
>: >
>: 
>: Look Guys, what's the problem here?  If you want a light that goes on when 
>: the 'phone is *Off* hook, all you need it to run it in *series* with the 
>: line, as I mentioned in my previous post.  If you want a light that goes on 
>: when the 'phone is *on* hook, all you need is a voltage threshold detector.
>
>If you're going to do the series Diode thing (which is the easiest), just
>make sure that the LED can take the current (I can't recall it off-hand, but
>it's something like 100mA or more?)

Careful now folks... Also consider the 90VAC+ @20Hz that is forced on ring
and tip when the phone's supposed to ring!  Even with a simple zener
and LED setup, you might end up with some carbon real quick.  Whatever
scheme you use, make sure you've got at least 200V-rated components on 
the frontend.

Also remember that, if I'm not mistaken, the phone line is a 600ohm
equivalent circuit.  Any current you draw from the 48V or so gets
dropped across that 600ohms.  That's fine until you're down to roughly
12V, when Ma Bell considers it to be off-hook.  But dropping it that
far down is probably a big no-no.

The easiest implementation to accomplish the above??

    tip  ------->|-----\/\/\/\-----+----------+
              rectifier  resistor  |          |
              diode                |          \ 
                                   V          /
                          zener  /---/        \  resistor
                                   |          /
                                   |          |
                                   |          V   LED
                                   |         ---
                                   |          |
    ring --------------------------+----------+

This is only a suggestion...go ahead and blow holes in it, but you
get the idea.  Choose a high-efficiency LED so you don't need much
current to get it to light up.  Choose values for the other components
as required.

aaron


Newsgroup: sci.electronics
document_id: 53556
From: alung@megatest.com (Aaron Lung)
Subject: Re: Uninterruptible Power Supply

In article <1qk724INN474@hp-col.col.hp.com> cab@col.hp.com (Chris Best) writes:
>I'm no expert at UPS's, but you said something that made it sound like
>you didn't realize something.  On a typical UPS (well, on ours, anyway),
>there is NO switchover from AC to DC.  All the protected equipment is
>ALWAYS running from the batteries (via an inverter), with the usual 
>condition of also having them on charge.  If the power fails, big deal - 
>the computers never see it (until the batteries start to droop, but 
>there's something like 60 car-sized batteries in that cabinet, so it 
>takes a while).
>
>If you were gonna run the guts on straight DC instead of an inverter,
>why not do it all the time?  Then there'd be no switchover to screw
>things up, and no having to sense the failure fast.  Just keep the DC
>on charge when the power is on, and it'll be there in zero time when
>you "need" it.
>

Actually, it's a bit more complicated than that...I sounds to me,
your UPS takes in AC, rectifies it to DC to charge the batteries, and
then takes the battery DC and chops it to AC again, feeding your
equipment.  This approach is the easiest and cleanest way to
switchover from the mains to battery once your power kicks out since,
as you mentioned, nothing will know about what happened down the line.

Another way to do the UPS scheme is to use the mains until you
lose power, and then kick in the battery backup with it's inverter to
replace the lost power.  The problem here is the switchover time and
you've got to resync the AC in no time flat.

Unfortunately, most everything is built around the assumption that
AC is available, so the UPS guys have to provide and AC output to
be usable...ya sorta have to make it work with what there already.

Similar story with our telephone system.  It was first invented back
in the 1800's.  We're still using the same damn system (media) as they
did back then.  If I have a phone from back then, I can assure you
it'll work on today's phone system.  It costs too much to overhaul
everyone to a new system, so they make it work with what is out there.

.

Newsgroup: sci.electronics
document_id: 53557
From: alung@megatest.com (Aaron Lung)
Subject: Re: Exploding TV!

In article <1qk4hj$qos@vtserf.cc.vt.edu> prasad@vtaix.cc.vt.edu (Prasad Ramakrishna) writes:
>I had a GE Emerson 13" color TV for about 3 years and one fine day,
>while we were watching something (I doubt if the program was the cause),
>we heard a mild explosion.   Our screen went blank but there was sound,
>so we thought, 'oh we have special effects on the program'.  But soon
>the sound stopped and smoke started to appear at the back of the TV.
>The brilliant EEs we are, we unplugged the TV and called customer service
>only to be thrown around by please hold, I will transfer u to blah blah..
>  Finally we abandoned the idea of trying to fix the TV and got a new one
>(we wanted a bigger one too!).
> After all the story, what I wanted to know is: Is my problem an isolated
>incident or a common one? (I recall reading about Russian TVs exploding, but
>not here, in the US). Why would the picture tube explode or even smoke?
> I still have the left over TV set, I might dig into it this summer. Any
>idea where I can get parts for these things? (probably will cost more than TV).
>

Heh, heh, heh, heh....I laugh because I have the same damn TV, and it
did the same thing!  Actually it is a Goldstar, but it's essentially the
same TV and electronics--just a different face plate and name.

#1.  Fortunately, TV tubes don't explode.  I'd think the TV mfrs want
to make this possibility remote as possible.  If at all, they'll 
*implode* and the glass that blows out would be the result of the
glass boucing off the back of the tube due to the implosion. In any
case, don't kick it around! :-) 

#2  I fixed the TV after getting a hold of some schematics.  It turned
out to be a blown 2W resistor feeding the flyback transformer.  I guess
the original resistor was a bit too small to dissipate the heat it
created, burning itself out.  I checked to make sure the flyback wasn't
shorted or anything first!  Oh, luckily, I had a resistor handy lying
around that had just the right value for what I needed.  I can't see it
being more than 50 cents!.

Well, needless to say, the TV still works today.  So go get a set of
schematics and have some fun...just don't get shocked poking around
the flyback.


Newsgroup: sci.electronics
document_id: 53558
From: <LEEK@QUCDN.QueensU.CA>
Subject: Re: ADC card for computer

In article <1qi8e3$b5e@lll-winken.llnl.gov>, you say:
>
>I would like to digitize the output of a SQUID magnetometer (range -10 V
>to +10 V) and do digital signal processing in a computer, say a Macintosh
>II or a 486 PC.  I would like a good 16 bit ADC with good linearity and a
>high conversion speed, at least 50 kHz, preferably 200 kHz.  Other concerns
>
>(2)  Must I use an ADC external to my computer to avoid digital noise
>     feedback into my sensitive SQUID electronics?

Might be a good idea...  The resolution you requested is about 0.3mV
In order to get what you've paid for, noise level better be lower than
that.  It is kind of hard to do it in a noisy box like you can expect
inside a PC.

Before you pay $$$ for a PC card, test it out by sampling a low
distortion sine wave (I think there is a sine wave on a CD.  Digital
Domain ?  There are possibly other low THD sources)  Run the digitized
waveform through a FFT transform and take alook at the noise floor on
the spectrum.  That's should give you a good indication of the design.
(That's what I am doing to test a data acquistion system I have designed
- I got the idea from MAXIM data sheet.)

If you can live with 14 bit resolution, I would recommend looking at
the MAX121 from MAXIM.  It is a high speed (308KHz) complete
sampling A/D with DSP interface.  The input range is +/- 5V and it
uses a serial interface (which can easily be optically isolated
from the computer to elinimate a major noise source)  The Analog design
guide I got from them shows a -100db noise level.  They claim a -77db
max (-85 typ.) THD.  Looks pretty good for the $12 @ 1000 pieces

A evaluation kit is available.  Might want to give these nice folks a
call.  1-800-998-8800 or fax: (408)737-7194 and (408) 737-7600 ext4000
for application assistance.

This assumes that you can build your own DAS and write your own software.
(Hey you can get the MAX121 as a free sample just by calling the 1-800 #)

>I would appreciate discussion of your personal experience with a Mac or PC-
>based ADC system.

I would recommend you to find out the resolution that can be gotten out
of your system by looking at the noise level, otherwise you might be
throwing out your money.

>Charles Cunningham
>cec@imager.llnl.gov

K. C. Lee
Elec. Eng. Grad. Student

I have no connection with MAXIM except I do in general recommend
companies that give samples to students to others.  I feel they
deserve that for being nice to me.

Newsgroup: sci.electronics
document_id: 53559
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: what to do with old 256k SIMMs?

In article <120466@netnews.upenn.edu>, jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
|> 
|> 	I was wondering if people had any good uses for old
|> 256k SIMMs.  I have a bunch of them for the Apple Mac
|> and I know lots of other people do to.  I have tried to
|> sell them but have gotten NO interest.
|> 
|> 	So, if you have an inovative use (or want to buy
|> some SIMMs  8-) ), I would be very interested in hearing
|> about it.

The most practical use I've seen for them is as key ring ornaments :-)

JohnH

Newsgroup: sci.electronics
document_id: 53560
From: sknapp@iastate.edu (Steven M. Knapp)
Subject: Re: Radar detector DETECTORS?

In article <oxenreid.734127163@chaos.cs.umn.edu> oxenreid@chaos.cs.umn.edu () writes:
>In <1993Apr06.173031.9793@vdoe386.vak12ed.edu> ragee@vdoe386.vak12ed.edu (Randy Agee) writes:
>
>>So, the questions are -

>>  Are any brands "quieter" than others?

Yes some radar detectors are less detectable by radar detector
detectors. ;-)

Look in Car and Driver (last 6 months should do), they had a big
review of the "better" detectors, and stealth was a factor.
________________________________________________________________________ 
Steven M. Knapp                             Computer Engineering Student
sknapp@iastate.edu                  President Cyclone Amateur Radio Club
Iowa State University; Ames, IA; USA      Durham Center Operations Staff

Newsgroup: sci.electronics
document_id: 53561
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Subject: Re: making copy of a Video tape

>There are devices you can buy and/or make.  Look in Radio & Popular 
>Electronics mags for the devices.  If all else fails, you can build one 
>using the curcuit design from the Dec. '87 issue of Radio Electronics.

My very favorite ad for such a device is on the back of the latest
Damark catalog.  Quoting from memory:

[Big flashy type]
"Dual deck VCR copies any tape -- Even those that are copy protected!*"

(And underneath the ad in very small print: *This device is not intended
for making illegal copies of copyrighted material.)

:-)

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
Vote straight ticket Procrastination party Dec. 3rd!

Newsgroup: sci.electronics
document_id: 53562
From: russotto@eng.umd.edu (Matthew T. Russotto)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <1993Apr14.174857.28314@porthos.cc.bellcore.com> dje@bmw535.NoSubdomain.NoDomain (Don Eilenberger) writes:
}In article <1993Apr14.153740.18542@nimbus.com>, jimiii@nimbus.com (Jim Warford) writes:

}|>  There are two simple procedures for alterating any odometer.
}|> 
}|> 1. Mechanical driven odometer:
}|>     Remove the speedo cable from the transmission.
}|>     Attach a drill and run at max speed until the speedo turns over.
}|>     Continue until the desired mileage is reached.
}|> 
}|> 2. Electronically driven odometer:
}|>     Remove the sensor wire from the sensor.
}|>     Attach the Calibration out signal from an Oscope to the wire.
}|>     Run until the speedo turns over and attains the desired mileage.
}
}Dear Faster.. I kinda wonder.. have you ever tried version 2? On what?
}Since the sensor wire on a BMW feeds also into the computer.. and we
}don't know what signal voltage is expected from it.. bad things
}*could* happen... also since we don't know the pulse rate, we
}may damage the analog part of the speedo (yes.. BMW uses a combined
}instrument.. speed in analog, trip and total milage is digital) with
}the needle pegged up against the 160MPH stop..
}
}Just a thought...

You've got the oscilliscope, so you connect it up to the sensor wire
and measure this stuff.  That way you know what it expects.

-- 
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
Some news readers expect "Disclaimer:" here.
Just say NO to police searches and seizures.  Make them use force.
(not responsible for bodily harm resulting from following above advice)

Newsgroup: sci.electronics
document_id: 53563
From: ritterbus001@wcsub.ctstateu.edu
Subject: Re: Picking up cable tv with an aerial.

In article <gyJX2B2w165w@inqmind.bison.mb.ca>, dino@inqmind.bison.mb.ca (Tony stewart) writes:
> jfsenior@unix1.tcd.ie (John Senior) writes:
> 
>> Recently, I discovered that it was possible to receive cable
>> tv through the telescopic aerial on the top of my tv.
>> The nearer this aerial is moved to the cable (which I am not
>> connected to) which runs under the eaves of the house the better
>> the signal.  Now, I was wondering how can I improve the signal?
>> Is it possible to improve the signal significantly? (some channels
> 
> CABLE EGRESS or emanations if you will are being radiated at free space 
> impedance from cables that may be harmonically realated to certain 
> channels and therfore the standing waves at 1/4 wave will transfer 
> efficiently. Also your antenna (a loose monopole) is also harmonically 
> tuned and will be more efficient at 1/2 wavelength multiples.
> 
> Your best bet for this research is to use a tuned YAGI antenna to get the 
> gain you need. (Std TV roof antenna type) The dipoles should be parallel 
> to the radiating cable. A pre-amp doesn't help significantly in my 
> experience in most cases.
> 
> dino@inqmind.bison.mb.ca
> The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Wow, what a concept!  Does anybody want to speculate on how this
"non-connection" would fit into the theft of cable services laws?
It seems to me that unless this case is specifically written into
the legislation that the cable company would not have a leg to
stand upon in court.

Does anybody out there have any specific legal knowledge on this?

Jim Ritterbusch
ritterbus001@wcsu.ctstateu.edu    - or - ne22@radiomail.net  (temp, rf)
There is an art, the Guide says, or rather a knack to flying.  The
knack lies in learning how to throw yourself at the ground and miss.


Newsgroup: sci.electronics
document_id: 53564
From: doherty@coolpro.melpar.esys.com (Kevin Doherty)
Subject: Hard Drive Component Costs

  Does anyone have some information on the relative fraction of the final
cost of each component in an average hard drive?  For instance, I'm pretty
sure the heads and the platters are the most expensive parts, with the
assembly costs running a close third.  Cost of the electronics is likely
in the noise.
  Any hard numbers ($$ or percentage)?  Thanks.


+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| Kevin Doherty           E-Systems/Melpar Division   doherty@melpar.esys.com |
| Principal Engineer      Falls Church, VA 22046      (703) 560-5000x2659     |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
-- 
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| Kevin Doherty           E-Systems/Melpar Division   doherty@melpar.esys.com |
| Principal Engineer      Falls Church, VA 22046      (703) 560-5000x2659     |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+

Newsgroup: sci.electronics
document_id: 53565
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Radar detector DETECTORS?

alee@bmerh794.bnr.ca (Louis Leclerc) writes:

> 
> In article <34263@oasys.dt.navy.mil> you write:
> >VA, CT, Wash DC  and I think BC Canada where I've heard they actually
> >use Radar detector detectors.
> 
> Nope, not in British Columbia.  Detectors are legal here in BC, I've even
> got one.
> 
> In Alberta and Ontario they're illegal, and detection devices are sometimes
> used.  I've heard the police in Ontario prefer a much more direct method of
> detection.  Just trigger the radar gun, watch for people slamming on the
> brakes, and search the car.
> 
> 
> David Lee
> leex@sfu.ca
> 


They are illegal here in Manitoba as well though I don't know what 
methods are used to detect them.

It has always amazed me with the way the laws work.  It is not illegal to 
sell them here in Manitoba, only to have them within a vehicle.  (Last I 
heard, they don't have to be installed to be illegal.)

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 53566
From: mkilpela@mtu.edu (Mark E. Kilpela)
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>,
crisp@ecsvax.uncecs.edu (Russ Crisp) wrote:
> 
> Hello
> I'm considering modernizing some old wiring in my home, and
> I need a little advice on outlet wiring.  Several outlets
> are the old 'two prong' type, without the ground.  Naturally,
> the wire feeding these outlets is 12/2, WITHOUT the ground
> wire.  I noticed at the fusebox that some circuits have the
> 12/2 with ground, and that on these circuits, the ground
> wire was tied to the same bus as the neutral (white) wire.
> 
> SO..  Here's my question.  It seems to me that I'd have the
> same electrical circuit if I hooked the neutral[D[D[D[D[D[D[D[D[D[D[Da jumper from the neutral
> over to the ground screw on new 'three prong' grounding outlets.
> What's wrong with my reasoning here?  

First, it will not pass a National Electrical code inspection.
Secondly, The neutral wire is current carrying and the ground wire
shouldn't be, or only during a fault condition.

The reason the neutral and ground are tied together in the panel is the
tranformer on the power pole has a grounded center-tap secondary, with the
grounded center-tap the neutral.  This gives 120v to neutral(ground) from
each side of the transformer and 240v across the transformer.  So in effect
the neutral and ground should be at the same potential. 

------------------------------------------------------------------
Mark E. Kilpela              email mkilpela@mtu.edu
Michigan Technological University
School of Technology
------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53567
From: swalker@uts.EDU.AU (-s87271077-s.walker-man-50-)
Subject: What do Nuclear Site's Cooling Towers do?



I really don't know where to post this question so I figured that
this board would be most appropriate.
I was wondering about those massive concrete cylinders that
are ever present at nuclear poer sites. They look like cylinders
that have been pinched in the middle. Does anybody know what the
actual purpose of those things are?. I hear that they're called
'Cooling Towers' but what the heck do they cool?
I hope someone can help 



Newsgroup: sci.electronics
document_id: 53568
From: jeh@cmkrnl.com
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
> I'm considering modernizing some old wiring in my home, and
> I need a little advice on outlet wiring.  Several outlets
> are the old 'two prong' type, without the ground.  Naturally,
> the wire feeding these outlets is 12/2, WITHOUT the ground
> wire.  I noticed at the fusebox that some circuits have the
> 12/2 with ground, and that on these circuits, the ground
> wire was tied to the same bus as the neutral (white) wire.
> 
> SO..  Here's my question.  It seems to me that I'd have the
> same electrical circuit if I hooked the jumper from the neutral
> over to the ground screw on new 'three prong' grounding outlets.
> What's wrong with my reasoning here?  

No.  No.  NOOO!!!

The ground (green) wire is for safety.  No current is supposed to flow in it
under normal conditions.  This means that there's normally no voltage drop in
it either.  It is supposed to be safe to touch the ground wire... even if
you're grounded in some other way at the same time.  

The neutral (white) wire is, as Dave Vanderbyl correctly said, the return for
the hot wire.  Since current flows in it, there's a voltage drop.  If you
plug a heavy load into a properly-wired grounded outlet, you can commonly 
measure a volt or so of difference between neutral and ground.  

They are supposed to be connected together at the breaker panel... but nowhere,
repeat NOwhere, else.  (Well, almost.  There are strange exceptions for things
like sub-panels.)

What you CAN do if you want three-prong outlets without additional wiring is 
to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
depending on where you are putting your new outlet(s), a GFCI may be *required*.

There is a FAQ on electrical wiring, posted regularly to rec.woodworking and
news.answers.  It goes into great detail on these issues (including GFCIs) and
you should probably read it before asking any more questions.  I'll mail a copy
to you, append a copy here, and will ask the writers to cross-post it here in
the future. 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055


Newsgroup: sci.electronics
document_id: 53569
From: jeh@cmkrnl.com
Subject: Electrical wiring FAQ (was: A question about 120VAC outlet wiring..

Since electrical wiring questions do turn up from time to time on
sci.electronics (and the answers aren't always apparent, even to those skilled
in electronics), I am hijacking the following FAQ and posting a copy here. 
I've asked the writers to cross-post to sci.electronics in the future. 

	--- jeh@cmkrnl.com


X-NEWS: cmkrnl news.answers: 6685
Newsgroups: misc.consumers.house,rec.woodworking,news.answers,misc.answers,rec.answers
Subject: Electrical Wiring FAQ
Message-ID: <wirefaq_733900891@ecicrl>
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Date: 4 Apr 93 05:21:49 GMT
Reply-To: wirefaq@ferret.ocunix.on.ca (Wiring FAQ commentary reception)
Followup-To: poster
Expires: 2 May 93 05:21:31 GMT
Organization: Elegant Communications Inc., Ottawa, Canada
Summary: A series of questions and answers about house wiring
Approved: news-answers-request@mit.edu
Supersedes: <wirefaq_732691289@ecicrl>
Lines: 1524

Archive-name: electrical-wiring
Last-modified: Sun Feb 21 16:56:10 EST 1993

	    Frequently Asked Questions on Electrical Wiring

		Steven Bellovin (smb@ulysses.att.com)
		Chris Lewis (clewis@ferret.ocunix.on.ca)

	    Comments to (automatic if you reply to this article):
		    wirefaq@ferret.ocunix.on.ca

This FAQ is formatted as a digest.  Most news readers can
skip from one question to the next by pressing ^G.

Answers to many other topics related to houses can be obtained from
the misc.consumers.house archive; send an empty piece of mail to
house-archive@dg-rtp.dg.com for information.

Changes to previous issue marked with "|" in left column.  Watch
particularly for "NEW" in the Questions list for new or substantively
changed answers.

Note that this is now a registered FAQ - cross-posted to news.answers
and should appear in the FAQ list of lists.

Subject: Questions answered in this FAQ

	Introduction/Disclaimers
	What is the NEC?  Where can I get a copy?
	What is the CEC?  Where can I get a copy?
	Can I do my own wiring?  Extra pointers?
	What do I need in the way of tools?
	What is UL listing?
	What is CSA approval?
	Are there any cheaper, easier to read books on wiring?
	Inspections how and what?  Why should I get my wiring inspected?
	My house doesn't meet some of these rules and regulations.
	A word on voltages: 110/115/117/120/125/220/240
	What does an electrical service look like?
	What is a circuit?
	"grounding" versus "grounded" versus "neutral".
	What does a fuse or breaker do?  What are the differences?
	Breakers?  Can't I use fuses?
	What size wire should I use?
	Where do these numbers come from?
	What does "14-2" mean?
	What is a "wirenut"/"marrette"/"marr connector".  How are they used?
	What is a GFI/GFCI?
	Where should GFCIs be used?
	Where shouldn't I use a GFCI?
	What is the difference between a GFCI outlet and a GFCI breaker?
	What's the purpose of the ground prong on an outlet, then?
	Why is one prong wider than the other?  Polarization
	What kind of outlets do I need in a kitchen?
	Where must outlets and switches be in bathrooms?
	What is Romex/NM/NMD?  What is BX?  When should I use each?
	Should I use plastic or metal boxes?
	Junction box positioning?
	Can I install a replacement fixture?
	What does it mean when the lights brighten when a motor starts?
	What is 3 phase power?  Should I use it?  Can I get it in my house?
	Is it better to run motors at 110 or 220?
	What is this nonsense about 3HP on 110V 15A circuits?
	How do I convert two prong receptacles to three prong?
	Are you sure about GFCIs and ungrounded outlets?
	    Should the test button work?
	How should I wire my shop?
	Underground wiring
	Aluminum wiring
	I'm buying a house!  What should I do?
	What is this weird stuff?  Old style wiring
	Where do I buy stuff?


Subject: Introduction/Disclaimers

	Although we've done a fair bit of wiring, we are not
	electricians, and we cannot be responsible for what you do.  If
	you're at all uncertain about what is correct or safe, *don't
	do it*.  Contact someone qualified -- a licensed electrician,
	or your local electrical inspector.  Electricity is no joke;
	mistakes can result in shocks, fires, or electrocution.

	Furthermore, our discussion is based on the U.S. National
	Electrical Code (NEC) and the Canadian Electrical code (CEC).
	To the best of our abilities, we have confirmed every detail
	with the electrical code, but we don't quote sections
	simply to keep this thing readable.  If you think we're wrong,
	we invite you to correct us, but please - quote references!

	The NEC and the CEC do not, in and of themselves, have the
	force of law.  Many municipalities adopt it en toto.  Others,
	however, do not.  Check your with your local building
	department (and <provincial> Hydro Inspection Offices in
	Canada) to find out what applies in your area.  Also,
	your local electrical utility may also have special requirements
	for electrical service installation.  Bear in mind, too, that
	we say here applies primarily to ordinary single-family
	residences.  Multi-family dwellings, mobile homes, commercial
	establishments, etc., are sometimes governed by different
	rules.

	Also note that, contrary to popular belief in the U.S. (and in
	some parts of Canada), Canada is not a wholly-owned subsidiary
	of the U.S.  Consequently, the NEC does not apply in Canada.
	Lots of things are the same, including voltages, line
	frequencies, and the laws of physics.  But there are a number
	of crucial differences in the regulations.  Where we can, we've
	noted them, flagging the relevant passages with ``NEC'' or
	``CEC''.

	Remember that the CEC and NEC are minimal standards.  It is often
	smart to go beyond their minimal requirements.

Subject: What is the NEC?  Where can I get a copy?

	The NEC is a model electrical code devised and published by the
	National Fire Protection Association, an insurance industry group.
	It's revised every three years.  The 1993 version has been released.
	You can buy a copy at a decent bookstore, or by calling them directly
	at 800-344-3555.  The code exists in several versions.  There's the
	full text, which is fairly incomprehensible.  There's an abridged
	edition, which has only the sections likely to apply to most houses.
	And there's the NEC Handbook, which contains the ``authorized
	commentary'' on the code, as well as the full text.  That's the
	recommended version.  Unfortunately, there's no handbook for
	the abridged edition.  And the full handbook is expensive --
	US$65 plus shipping and handling.

Subject: What is the CEC?  Where can I get a copy?

	The Canadian Standards Association is an organization made up
	of various government agencies, power utilities, insurance
	companies, electrical manufacturers and other organizations.
	The CSA publishes CSA Standard C22.1 which is updated every two
	or three years.  Each province adopts, with some amendments,
	this standard and publishes a province-specific code book.
	Since each province publishes its own slightly modified
	standard, it would be somewhat confusing to obtain the CSA
	standard itself.  In this FAQ, "CEC" really means the
	appropriate provincial standard.  In particular, this FAQ is
	derived from the Ontario Hydro Electrical Safety Code, 20th
	edition (1990).  Which is in turn based on CSA C22.1-1990 (16th
	edition).  While differences exist between the provinces, an
	attempt has been made to avoid specific-to-Ontario detail.

	The appropriate provincial code can be obtained from electrical
	inspection offices of your provincial power authority.  In
	Ontario, it's Ontario Hydro.  The Ontario Hydro book isn't
	overly fat.  It's about C$25, and includes mailed updates.  I
	hear that these standards are somewhat easier to read than the
	equivalent NEC publications.

	Don't bother asking in Quebec - DIY wiring is banned throughout
	the province.

Subject: Can I do my own wiring?  Extra pointers?

	In most places, homeowners are allowed to do their own wiring.
	In some, they're not.  Check with your local electrical
	inspector.  Most places won't permit you to do wiring on other's
	homes for money without a license.  Nor are you permitted to do
	wiring in "commercial" buildings.  Multiple dwellings (eg: duplexes)
	are usually considered "semi-commercial" or "commercial".  However,
	many jurisdictions will permit you to work on semi-commercial
	wiring if you're supervised by a licensed electrician - if you can
	find one willing to supervise.

	If you do your own wiring, an important point:

	Do it NEAT and WELL!  What you really want to aim for is a better
	job than an electrician will do.  After all, it's your own home,
	and it's you or your family that might get killed if you make
	a mistake.  An electrician has time pressures, has the skills
	and knows the tricks of the trade to do a fast, safe job.
	In this FAQ we've consciously given a few recommendations that
	are in excess of code, because we feel that it's reasonable,
	and will impress the inspector.

	The inspector will know that you're an amateur.  You have to
	earn his trust.  The best way of doing this is to spend your
	time doing as neat a job as possible.  Don't cut corners.
	Exceed specifications.  Otherwise, the inspector may get extremely
	picky and fault you on the slightest transgressions.

	Don't try to hide anything from the inspector.

	Use the proper tools.  Ie: don't use a bread knife to strip
	wires, or twist wires with your fingers.  The inspector
	won't like it, and the results won't be that safe.  And it
	takes longer.  And you're more likely to stick a hunk of
	12ga wire through your hand that way.

	Don't handle house wire when it's very cold (eg: below -10C
	or 16F).  Thermoplastic house wire, particularly older types
	become very brittle.

Subject: What do I need in the way of tools?

	First, there's the obvious -- a hammer, a drill, a few
	screwdrivers, both straight and Phillips-head.  If you're 
	lucky enough to live in Canada (or find a source of CSA-approved
	devices) you need Robertson ("square recess") screwdrivers
	(#1 and #2) instead of phillips.

	For drilling a few holes, a 3/4" or 1" spade bit and 1/4" or
	3/8" electric drill will do.  If you're doing a lot, or
	are working with elderly lumber, we recommend a 1/2" drill
	(right-angle drills are wonderful.  Can be rented) and
	3/4" or 1" screw-point auger drill bits.  These bits pull
	you through, so they're much faster and less fatiguing, even
	in 90 year old hardwood timbers.

	Screw-driver bits are useful for drills, expecially if you
	install your electrical boxes using screws (drywall screws
	work well).
	
	For stripping wire, use a real wire stripper, not a knife or
	ordinary wire cutters.  Don't buy the $3 K-mart "combo stripper,
	crimper and bottle opener" types.  You should expect to pay
	$15 to $20 for a good "plier-type" pair.  It will have sized
	stripping holes, and won't nick or grab the wire - it should
	be easy to strip wire with it.  One model has a small hole in the
	blade for forming exact wire loops for screw terminals.  There
	are fancier types (autostrip/cut), but they generally aren't
	necessary, and pros usually don't use them.

	A pair of diagonal side cutter pliers are useful for clipping ends
	in constricted places.  Don't use these for stripping wire.

	You will need linesman pliers for twisting wires for wire nuts.

	You should have a pair of needle-nose pliers for fiddling
	inside boxes and closing loops, but it's better to form wire
	loops with a "loop former hole" on your wire stripper - more
	accurate.

	If you're using non-metallic cable, get a cable stripper for
	removing the sheath.  Or, do what some pros do, they nick the
	end of the sheath, grab the ground wire with a pair of pliers,
	and simply rip the sheath back using the ground wire as a
	"zipper", and cut the sheath off.  You shouldn't try to strip
	the sheath with a knife point, because it's too easy to
	slash the insulation on the conductors.  Apparently Stanley
	utility knives fitted with linoleum cutters (hooked blades)
	can be used to strip sheath, but there is still the possibility
	that you'll gouge the conductors.

	For any substantial amount of work with armored cable, it's well
	worth your while to invest in a rotary cable splitter (~US$ 18).
	Hack saws are tricky to use without cutting into the wire
	or the insulation.

	Three-prong outlet testers are a quick check for properly-wired
	outlets.  About $6.  Multimeters tell you more, but are a lot more
	expensive, and probably not worth it for most people.  A simple
	voltage sensor, which can detect potential through an insulated
	wire not supplying any devices, is extremely helpful; they cost
	about US$ 10 at Radio Shack.

	You should have a voltage detector - to check that the wires are
	dead before doing work on them.  Neon-bulb version are cheap ($2-3)
	and work well.  If you get more serious, a "audible alarm" type is
	good for tracing circuits without a helper.  (Though I've been known
	to lock the drill on, and hit breakers until the scream stops ;-)

	For running wires through existing walls, you need fish tape.
	Often, two tapes are needed, though sometimes, a bent hanger or
	a length of thin chain will suffice.  Fish tapes can be rented.

	Electrical tape.  Lots of it ;-)  Seriously, a good and competent
	wiring job will need very little tape.  The tape is useful for
	wrapping dicy insulation in repair work.  Another use is to wrap 
	around the body of outlets and switches to cover the termination
	screws - I don't do this, but drywall contractors prefer it (to
	prevent explosions when the drywall knife collides with a live outlet
	that has no cover plate).

Subject: What is UL listing?

	The UL stands for "Underwriters Laboratory".  It used to be
	an Insurance Industry organization, but now it is independent
	and non-profit.  It tests electrical components and equipment
	for potential hazards.  When something is UL-listed, that means
	that the UL has tested the device, and it meets their requirements
	for safety - ie: fire or shock hazard.  It doesn't necessarily
	mean that the device actually does what it's supposed to, just
	that it probably won't kill you.

	The UL does not have power of law in the U.S. -- you are
	permitted to buy and install non-UL-listed devices.  However,
	insurance policies sometimes have clauses in them that will
	limit their liability in case of a claim made in response to
	the failure of a non-UL-listed device.  Furthermore, in
	many situations the NEC will require that a wiring component
	used for a specific purpose is UL-listed for that purpose.
	Indirectly, this means that certain parts of your wiring
	must be UL-listed before an inspector will approve it and/or
	occupancy permits issued.
	
Subject: What is CSA approval?

	Every electrical device or component must be certified by the
	Canadian Standards Association before it can be sold in
	Canada.  Implicit in this is that all wiring must be done
	with CSA-approved materials.  They perform testing similar to
	the UL (a bit more stringent), except that CSA approval is
	required by law.

	Again, like the UL, if a fire was caused by non-CSA-approved
	equipment, your insurance company may not have to pay the
	claim.

	In Canada, there is a branch organization of the UL, called ULC
	(UL of Canada).  ULC does not have power of law, and seems to
	be more a liason group between the CSA and insurance
	companies.

Subject: Are there any cheaper, easier to read books on wiring?

	USA: The following three books were suggested by our readers

	    Residential Wiring
	    by Jeff Markell,
	    Craftsman Books,
	    Carlsbad CA for $18.25. ISBN 0-934041-19-9.

	    Practical Electrical Wiring
	    Residential, Farm and Industrial,  Based on the National
	    Electrical Code    ANSI/NFPA 70
	    Herbert P. Richter and W. Creighton Schwan
	    McGraw-Hill Book Co.

	    Wiring Simplified
	    H. P. Richter and W. C. Schwan
	    Park Publishing Co.
	
	Try to make sure that the book is based on the latest NEC
	revision.  Which is currently 1990.

	Canada: P.S. Knight authors and publishes a book called
	"Electrical Code Simplified".  There appears to be a version
	published specific to each province, and is very tied into the
	appropriate provincial code.  It focuses on residential wiring,
	and is indispensible for Canadian DIY'ers.  It is better to get
	this book than the CEC unless you do a lot of wiring (or answer
	questions on the net ;-).

	It is updated each time the provincial codes are.  This book is
	available at all DIY and hardware stores for less than C$10.

Subject: Inspections how and what?  Why should I get my wiring inspected?

	Most jurisdictions require that you obtain a permit and
	inspections of any wiring that is done.  Amongst other more
	mundane bureaucratic reasons (like insurance companies not
	liking to have to pay claims), a permit and inspections
	provides some assurance that you, your family, your neighbors
	or subsequent owners of your home don't get killed or lose
	their homes one night due to a sloppy wiring job.

	Most jurisdictions have the power to order you to vacate your
	home, or order you to tear out any wiring done without a
	permit.  California, for instance, is particularly nasty about
	this.

	If fire starts in your home, and un-inspected wiring is at
	fault, insurance companies will often refuse to pay the damage
	claims.

	In general, the process goes like this:
		- you apply to your local inspections office or building
		  department for a permit.  You should have a sketch or
		  detailed drawing of what you plan on doing.  This is
		  a good time to ask questions on any things you're not
		  sure of.  If you're doing major work, they may impose
		  special conditions on you, require loading
		  calculations and ask other questions.  At this point
		  they will tell you which inspections you will need.
		- If you're installing a main panel, you will need to
		  have the panel and service connections inspected
		  before your power utility will provide a connection.
		  This is sometimes done by the local power authority
		  rather than the usual inspectors.
		- After installing the boxes and wiring, but before
		  the insulation/walls go up, you will need a
		  "rough-in" inspection.
		- After the walls are up, and the wiring is complete,
		  you will need a "final inspection".

Subject: My house doesn't meet some of these rules and regulations.
	Do I have to upgrade?

	In general, there is no requirement to upgrade older dwellings,
	though there are some exceptions (ie: smoke detectors in some
	cases).  However, any new work must be done according to the
	latest electrical code.  Also, if you do ``major'' work, you
	may be required to upgrade certain existing portions or all
	of your system.  Check with your local electrical inspector.

Subject: A word on voltages: 110/115/117/120/125/220/240

	One thing where things might get a bit confusing is the
	different numbers people bandy about for the voltage of
	a circuit.  One person might talk about 110V, another 117V
	or another 120V.  These are all, in fact, exactly the same
	thing...  In North America the utility companies are required
	to supply a split-phase 240 volt (+-5%) feed to your house.
	This works out as two 120V +- 5% legs.  Additionally, since there
	are resistive voltage drops in the house wiring, it's not
	unreasonable to find 120V has dropped to 110V or 240V has dropped
	to 220V by the time the power reaches a wall outlet.  Especially
	at the end of an extension cord or long circuit run.  For a number
	of reasons, some historical, some simple personal orneryness,
	different people choose call them by slightly different numbers.
	This FAQ has chosen to be consistent with calling them "110V" and
	"220V", except when actually saying what the measured voltage will
	be.  Confusing?  A bit.  Just ignore it.

	One thing that might make this a little more understandable
	is that the nameplates on equipment ofen show the lower (ie: 110V
	instead of 120V) value.  What this implies is that the device
	is designed to operate properly when the voltage drops that
	low.

	208V is *not* the same as 240V.  208V is the voltage between
	phases of a 3-phase "Y" circuit that is 120V from neutral to any
	hot.   480V is the voltage between phases of a 3-phase "Y"
	circuit that's 277V from hot to neutral.

	In keeping with 110V versus 120V strangeness, motors intended
	to run on 480V three phase are often labelled as 440V...

Subject: What does an electrical service look like?

	There are logically four wires involved with supplying the
	main panel with power.  Three of them will come from the utility
	pole, and a fourth (bare) wire comes from elsewhere.

 	The bare wire is connected to one or more long metal bars pounded
 	into the ground, or to a wire buried in the foundation, or sometimes
 	to the water supply pipe (has to be metal, continuous to where
	the main water pipe entering the house.  Watch out for galvanic
	action conductivity "breaks" (often between copper and iron pipe)).
	This is the "grounding conductor".  It is there to make sure that
	the third prong on your outlets is connected to ground.  This wire
	normally carries no current.

	One of the other wires will be white (or black with white or
	yellow stripes, or sometimes simply black).  It is the neutral wire.
	It is connected to the "centre tap" (CEC; "center tap" in the
	NEC) of the distribution transformer supplying the power.  It
	is connected to the grounding conductor in only one place (often
	inside the panel).  The neutral and ground should not be connected
	anywhere else.  Otherwise, weird and/or dangerous things may happen.

	Furthermore, there should only be one grounding system in
	a home.  Some codes require more than one grounding electrode.
	These will be connected together, or connected to the neutral
	at a common point - still one grounding system.  Adding additional
	grounding electrodes connected to other portions of the house
	wiring is unsafe and contrary to code.

	If you add a subpanel, the ground and neutral are usually
	brought as separate conductors from the main panel, and are
	not connected together in the subpanel (ie: still only one
	neutral-ground connection).  However, in some situations 
	(certain categories of separate buildings) you actually do
	have to provide a second grounding electrode - consult your
	inspector.

	The other two wires will usually be black, and are the "hot"
	wires.  They are attached to the distribution transformer as
	well.

	The two black wires are 180 degrees out of phase with each
	other.  This means if you connect something to both hot wires,
	the voltage will be 220 volts.  If you connect something to the
	white and either of the two blacks you will get 110V.

	Some panels seem to only have three wires coming into them.
	This is either because the neutral and ground are connected
	together at a different point (eg: the meter or pole) and one
	wire is doing dual-duty as both neutral and ground, or in some
	rare occasions, the service has only one hot wire (110V only
	service).

Subject: What is a circuit?

	Inside the panel, connections are made to the incoming wires.
	These connections are then used to supply power to selected
	portions of the home.  There are three different combinations:
		1) one hot, one neutral, and ground: 110V circuit.
		2) two hots, no neutral, and ground: 220V circuit.
		3) two hots, neutral, and ground: 220V circuit + neutral,
		   and/or two 110V circuits with a common neutral.

	(1) is used for most circuits supplying receptacles and
	lighting within your house.  (3) is usually used for supplying
	power to major appliances such as stoves, and dryers - they
	often have need for both 220V and 110V, or for bringing several
	circuits from the panel box to a distribution point.  (2) is
	usually for special 220V motor circuits, electric heaters, or
	air conditioners.

	[Note: In the US, the NEC frequently permits a circuit similar
	to (2) be used for stoves and dryers - namely, that there
	are two hot wires, and a wire that does dual duty as neutral
	and ground, and is connected to the frame as well as providing
	the neutral for 110V purposes - three prong plugs instead
	of four (*only* for stoves/dryers connected to the main panel.
	When connected to most sub-panels, 4 prong plugs and receptacles
	are required).  In our not-so-humble opinion this is crazy, but
	the NFPA claims that this practice was re-evaluated for the 1992 NEC,
	and found to be safe.  Check your local codes, or inquire as to
	local practice -- there are restrictions on when this is
	permissible.]

	(1) is usually wired with three conductor wire: black for hot,
	white for neutral, and bare for grounding.

	(2) and (3) have one hot wire coloured red, the other black, a
	bare wire for grounding, and in (3) a white wire for neutral.

	You will sometimes see (2) wired with just a black, white and ground
	wire.  Since the white is "hot" in this case, both the NEC and CEC
	requires that the white wire be "permanently marked" at the ends
	to indicate that it is a live wire.  Usually done with paint, nail
	polish or sometimes electrical tape.

	Each circuit is attached to the main wires coming into the
	panel through a circuit breaker or fuse.

	There are, in a few locales, circuits that look like (1), (2)
	or (3) except that they have two bare ground wires.  Some places
	require this for hot tubs and the like (one ground is "frame ground",
	the other attaches to the motor).  This may or may not be an
	alternative to GFCI protection.

Subject: "grounding" versus "grounded" versus "neutral".

	According to the terminology in the CEC and NEC, the
	"grounding" conductor is for the safety ground, i.e., the green
	or bare wire.  The word "neutral" is reserved for the white when
	you have a circuit with more than one "hot" wire.  Since the white
	wire is connected to neutral and the grounding conductor inside the
	panel, the proper term is "grounded conductor".  However, the
	potential confusion between "grounded conductor" and "grounding
	conductor" can lead to potentially lethal mistakes - you should
	never use the bare wire as a "grounded conductor" or white wire
	as the "grounding conductor", even though they are connected
	together in the panel.

	[But not in subpanels - subpanels are fed neutral and ground
	separately from the main panel.  Usually.]

	In the trade, and in common usage, the word "neutral" is used
	for "grounded conductor".  This FAQ uses "neutral" simply to
	avoid potential confusion.  We recommend that you use "neutral"
	too.  Thus the white wire is always (except in some light
	switch applications) neutral.  Not ground.

Subject: What does a fuse or breaker do?  What are the differences?

	Fuses and circuit breakers are designed to interrupt the power
	to a circuit when the current flow exceeds safe levels.  For
	example, if your toaster shorts out, a fuse or breaker should
	"trip", protecting the wiring in the walls from melting.  As
	such, fuses and breakers are primarily intended to protect the
	wiring -- UL or CSA approval supposedly indicates that the
	equipment itself won't cause a fire.

	Fuses contain a narrow strip of metal which is designed to melt
	(safely) when the current exceeds the rated value, thereby
	interrupting the power to the circuit.  Fuses trip relatively
	fast.  Which can sometimes be a problem with motors which have
	large startup current surges.  For motor circuits, you can use
	a "time-delay" fuse (one brand is "fusetron") which will avoid
	tripping on momentary overloads.  A fusetron looks like a
	spring-loaded fuse.  A fuse can only trip once, then it must be
	replaced.

	Breakers are fairly complicated mechanical devices.  They
	usually consist of one spring loaded contact which is latched
	into position against another contact.  When the current flow
	through the device exceeds the rated value, a bimetallic strip
	heats up and bends.  By bending it "trips" the latch, and the
	spring pulls the contacts apart.  Circuit breakers behave
	similarly to fusetrons - that is, they tend to take longer to
	trip at moderate overloads than ordinary fuses.  With high
	overloads, they trip quickly.  Breakers can be reset a finite
	number of times - each time they trip, or are thrown
	when the circuit is in use, some arcing takes place, which
	damages the contacts.  Thus, breakers should not be used in
	place of switches unless they are specially listed for the
	purpose.

	Neither fuses nor breakers "limit" the current per se.  A dead
	short on a circuit can cause hundreds or sometimes even
	thousands of amperes to flow for a short period of time, which
	can often cause severe damage.

Subject: Breakers?  Can't I use fuses?

	Statistics show that fuse panels have a significantly higher
	risk of causing a fire than breaker panels.  This is usually
	due to the fuse being loosely screwed in, or the contacts
	corroding and heating up over time, or the wrong size fuse
	being installed, or the proverbial "replace the fuse with a
	penny" trick.

	Since breakers are more permanently installed, and have better
	connection mechanisms, the risk of fire is considerably less.

	Fuses are prone to explode under extremely high overload.  When
	a fuse explodes, the metallic vapor cloud becomes a conducting
	path.  Result? from complete meltdown of the electrical panel,
	melted service wiring, through fires in the electrical
	distribution transformer and having your house burn down.
	Breakers don't do this.

	Many jurisdictions, particularly in Canada, no longer permit
	fuse panels in new installations.  The NEC does permit new
	fuse panels in some rare circumstances (requiring the special
	inserts to "key" the fuseholder to specific size fuses)

	Some devices, notably certain large air conditioners, require fuse
	protection in addition to the breaker at the panel.  The fuse
	is there to protect the motor windings from overload.  Check the
	labeling on the unit.  This is usually only on large permanently
	installed motors.  The installation instructions will tell you
	if you need one.

Subject: What size wire should I use?

	For a 20 amp circuit, use 12 gauge wire.  For a 15 amp circuit,
	you can use 14 gauge wire (in most locales).  For a long run,
	though, you should use the next larger size wire, to avoid
	voltage drops.  12 gauge is only slightly more expensive than
	14 gauge, though it's stiffer and harder to work with.

	Here's a quick table for normal situations.  Go up a size for
	more than 100 foot runs, when the cable is in conduit, or
	ganged with other wires in a place where they can't dissipate
	heat easily:

		Gauge		Amps
		14		15
		12		20
		10		30
		8		40
		6		65
	
	We don't list bigger sizes because it starts getting very dependent
	on the application and precise wire type.

Subject: Where do these numbers come from?

	There are two considerations, voltage drop and heat buildup.
	The smaller the wire is, the higher the resistance is.  When
	the resistance is higher, the wire heats up more, and there is
	more voltage drop in the wiring.  The former is why you need
	higher-temperature insulation and/or bigger wires for use in
	conduit; the latter is why you should use larger wire for long
	runs.

	Neither effect is very significant over very short distances.
	There are some very specific exceptions, where use of smaller
	wire is allowed.  The obvious one is the line cord on most
	lamps.  Don't try this unless you're certain that your use fits
	one of those exceptions; you can never go wrong by using larger
	wire.

Subject: What does "14-2" mean?

	This is used to describe the size and quantity of conductors
	in a cable.  The first number specifies the gauge.  The second
	the number of current carrying conductors in the wire - but
	remember there's usually an extra ground wire.  "14-2" means
	14 gauge, two insulated current carrying wires, plus bare ground.

	-2 wire usually has a black, white and bare ground wire.  Sometimes
	the white is red instead for 220V circuits without neutral.  In
	the latter case, the sheath is usually red too.

	-3 wire usually has a black, red, white and bare ground wire.
	Usually carrying 220V with neutral.

Subject: What is a "wirenut"/"marrette"/"marr connector"?  How are they
	used?

	A wire nut is a cone shaped threaded plastic thingummy that's used
	to connect wires together.  "Marrette" or "Marr connector"
	are trade names.  You'll usually use a lot of them in DIY wiring.

	In essence, you strip the end of the wires about an inch, twist them
	together, then twist the wirenut on.

	Though some wirenuts advertise that you don't need to twist the
	wire, do it anyways - it's more mechanically and electrically
	secure.

	There are many different sizes of wire nut.  You should check
	that the wire nut you're using is the correct size for the
	quantity and sizes of wire you're connecting together.

	Don't just gimble the wires together with a pair of pliers or
	your fingers.  Use a pair of blunt nose ("linesman") pliers,
	and carefully twist the wires tightly and neatly.  Sometimes
	it's a good idea to trim the resulting end to make sure it
	goes in the wirenut properly.

	Some people wrap the "open" end of the wirenut with electrical
	tape.  This is probably not a good idea - the inspector may
	tear it off during an inspection.  It's usually done because
	a bit of bare wire is exposed outside the wire nut - instead
	of taping it, the connection should be redone.

Subject: What is a GFI/GFCI?

	A GFCI is a ``ground-fault circuit interrupter''.  It measures
	the current current flowing through the hot wire and the
	neutral wire.  If they differ by more than a few milliamps, the
	presumption is that current is leaking to ground via some other
	path.  This may be because of a short circuit to the chassis of
	an appliance, or to the ground lead, or through a person.  Any
	of these situations is hazardous, so the GFCI trips, breaking
	the circuit.

	GFCIs do not protect against all kinds of electric shocks.  If,
	for example, you simultaneously touched the hot and neutral
	leads of a circuit, and no part of you was grounded, a GFCI
	wouldn't help.  All of the current that passed from the hot
	lead into you would return via the neutral lead, keeping the
	GFCI happy.

	The two pairs of connections on a GFCI outlet are not symmetric.
	One is labeled LOAD; the other, LINE.  The incoming power feed
	*must* be connected to the LINE side, or the outlet will not be
	protected.  The LOAD side can be used to protect all devices
	downstream from it.  Thus, a whole string of outlets can be
	covered by a single GFCI outlet.

Subject: Where should GFCIs be used?

	The NEC mandates GFCIs for 110V, 15A or 20A single phase
	outlets, in bathrooms, kitchens within 6' of the sink, garages,
	unfinished basements or crawl spaces, outdoors, near a pool, or
	just about anywhere else where you're likely to encounter water
	or dampness.  There are exceptions for inaccessible outlets,
	those dedicated to appliances ``occupying fixed space'',
	typically refrigerators and freezers, and for sump pumps and
	laundry appliances.

	The CEC does not mandate as many GFCIs.  In particular, there
	is no requirement to protect kitchen outlets, or most garage or
	basement outlets.  Basement outlets must be protected if you
	have a dirt floor, garage outlets if they're near the door to
	outside.  Bathrooms and most exterior outlets must have GFCIs.

	Even if you are not required to have GFCI protection, you may
	want to consider installing it anyway.  Unless you need a GFCI
	breaker (see below), the cost is low.  In the U.S., GFCI
	outlets can cost as little as US$8.  (Costs are a bit higher in
	Canada:  C$12.)  Evaluate your own risk factors.  Does your
	finished basement ever get wet?  Do you have small children?
	Do you use your garage outlets to power outdoor tools?  Does
	water or melted snow ever puddle inside your garage?

Subject: Where shouldn't I use a GFCI?

	GFCIs are generally not used on circuits that (a) don't pose a
	safety risk, and (b) are used to power equipment that must run
	unattended for long periods of time.  Refrigerators, freezers,
	and sump pumps are good examples.  The rationale is that GFCIs
	are sometimes prone to nuisance trips.  Some people claim that
	the inductive delay in motor windings can cause a momentary
	current imbalance, tripping the GFCI.  Note, though, that most
	GFCI trips are real; if you're getting a lot of trips for no
	apparent reason, you'd be well-advised to check your wiring
	before deciding that the GFCI is broken or useless.

Subject: What is the difference between a GFCI outlet and a GFCI breaker?

	For most situations, you can use either a GFCI outlet as the
	first device on the circuit, or you can install a breaker with
	a built-in GFCI.  The former is generally preferred, since GFCI
	breakers are quite expensive.  For example, an ordinary GE
	breaker costs ~US$5; the GFCI model costs ~US$35.  There is one
	major exception:  if you need to protect a ``multi-wire branch
	circuit'' (two or more circuits sharing a common neutral wire),
	such as a Canadian-style kitchen circuit, you'll need a
	multi-pole GFCI breaker.  Unfortunately, these are expensive;
	the cost can range into the hundreds of dollars, depending on
	what brand of panel box you have.  But if you must protect such
	a circuit (say, for a pool heater), you have no choice.

	One more caveat -- GFCI outlets are bulky.  You may want to use
	an oversize box when installing them.  On second thought, use
	large (actually deep) boxes everywhere.  You'll thank yourself for it.

	Incidentally, if you're installing a GFCI to ensure that one
	specific outlet is protected (such as a bathroom), you don't
	really have to go to all of the trouble to find the first
	outlet in the circuit, you could simply find the first outlet
	in the bathroom, and not GFCI anything upstream of it.  But
	protecting the whole circuit is preferred.

	When you install a GFCI, it's a good idea to use the little
	"ground fault protected" stickers that come with it and mark
	the outlets downstream of the GFCI.  You can figure out which
	outlets are "downstream", simply by tripping the GFCI with the
	test button and see which outlets are dead.

Subject: What's the purpose of the ground prong on an outlet, then?

	Apart from their use in electronics, which we won't comment on,
	and for certain fluorescent lights (they won't turn on without
	a good ground connection), they're intended to guard against
	insulation failures within the device.  Generally, the case of
	the appliance is connected to the ground lead.  If there's an
	insulation failure that shorts the hot lead to the case, the
	ground lead conducts the electricity away safely (and possibly
	trips the circuit breaker in the process).  If the case is not
	grounded and such a short occurs, the case is live -- and if
	you touch it while you're grounded, you'll get zapped.  Of
	course, if the circuit is GFCI-protected, it will be a very
	tiny zap -- which is why you can use GFCIs to replace
	ungrounded outlets (both NEC and CEC).

	There are some appliances that should *never* be grounded.  In
	particular, that applies to toasters and anything else with
	exposed conductors.  Consider:  if you touch the heating
	electrode in a toaster, and you're not grounded, nothing will
	happen.  If you're slightly grounded, you'll get a small shock;
	the resistance will be too high.  But if the case were
	grounded, and you were holding it, you'd be the perfect path to
	ground...

Subject: Why is one prong wider than the other?  Polarization

	Nowadays, many two-prong devices have one prong wider than the
	other.  This is so that the device could rely (not guaranteed!)
	on one specific wire being neutral, and the other hot.
	This is particularly advantageous in light fixtures, where the
	the shell should neutral (safety), or other devices which want to
	have an approximate ground reference (ie: some radios).

	Most 2-prong extension cords have wide prongs too.

	This requires that you wire your outlets and plugs the right
	way around.  You want the wide prong to be neutral, and the
	narrow one hot.  Most outlets have a darker metal for the
	hot screw, and lighter coloured screw for the neutral.
	If not, you can usually figure out which is which by which
	prong the terminating screw connects to.

Subject: What kind of outlets do I need in a kitchen?

	The NEC requires at least two 20 amp ``small appliance
	circuits'' for kitchens.  The CEC requires split-duplex
	receptacles.  Outlets must be installed such that no point is more
	than 24" (NEC) (900 mm CEC) from an outlet.  Every counter wider
	than 12" (NEC) or 300 mm (CEC) must have at least one outlet.
	The circuit these outlets are on may not feed any outlets except
	in the kitchen, pantry, or dining room.  Furthermore, these circuits
	are in addition to any required for refrigerators, stoves, microwaves,
	lighting, etc.  Non-dedicated outlets within 6' of a sink *must* be
	protected by a GFCI (NEC only).

	Split duplex receptacles are fed with a 220V circuit.  The tab
	is broken on the hot side of the outlet, and one hot goes to
	the upper outlet, and the other hot goes to the lower outlet.
	The neutral connects to both outlets through one screw.  When
	"carrying through" to another outlet, the neutral must be
	pigtailed, such that removing the outlet, or having the neutral
	connection fall off doesn't cause the neutral to disconnect
	from downstream outlets.

Subject: Where must outlets and switches be in bathrooms?

	There must be at least one outlet in each bathroom, adjacent to
	the sink, in addition to any outlet that may be incorporated in
	the light fixture.  All such outlets *must* be GFCI-protected.

Subject: What is Romex/NM/NMD?  What is BX?  When should I use each?

	Romex is a brand name for a type of plastic insulated wire.
	Sometimes called non-metallic sheath.  The formal name is NM.
	This is suitable for use in dry, protected areas (ie: inside
	stud walls, on the sides of joists etc.), that are not subject
	to mechanical damage or excessive heat.  Most newer homes are
	wired almost exclusively with NM wire.  There are several
	different categories of NM cable.

	BX cable -- technically known as armored cable or "AC" has a
	flexible aluminum or steel sheath over the conductors and is
	fairly resistant to damage.

	TECK cable is AC with an additional external thermoplastic
	sheath.
	
	Protection for cable in concealed locations: where NM or AC cable
	is run through studs, joists or similar wooden members, the outer
	surface of the cable must be kept at least 32mm/1.25" (CEC & NEC)
	from the edges of the wooden members, or the cable should be protected
	from mechanical injury.  This latter protection can take the form of
	metal plates (such as spare outlet box ends) or conduit.

	[Note: inspector-permitted practise in Canada suggests that armored
	cable, or flexible conduit can be used as the mechanical protection,
	but this is technically illegal.]

	Additional protection recommendations (these are rules in the
	Canadian codes - they are reasonable answers to the vague
	references to "exposed to mechanical damage" in both the NEC
	and CEC):

	    - NM cable should be protected against mechanical damage
	      where it passes through floors or on the surface of walls
	      in exposed locations under 5 feet from the floor.
	      Ie: use AC instead, flexible conduit, wooden guards etc.
	    - Where cable is suspended, as in, connections to furnaces
	      or water heaters, the wire should be protected.  Canadian
	      practise is usually to install a junction or outlet
	      box on the wall, and use a short length of AC cable
	      or NM cable in flexible conduit to "jump" to the appliance.
	      Stapling NM to a piece of lumber is also sometimes used.
	    - Where NM cable is run in close proximity to heating
	      ducts or pipe, heat transfer should be minimized by
	      means of a 25mm/1" air space, or suitable insulation
	      material (a wad of fiberglass).
	    - NM cable shall be supported within 300mm/1' of every box
	      or fitting, and at intervals of no more than 1.5m/5'.
	      Holes in joists or studs are considered "supports".
	      Some slack in the cable should be provided adjacent to
	      each box.  [while fishing cable is technically in violation,
	      it is permitted where "proper" support is impractical]
	    - 2 conductor NM cable should never be stapled on edge.
	      [Knight also insists on only one cable per staple, referring
	      to the "workmanship" clause, but this seems more honoured
	      in the breach...]
	    - cable should never be buried in plaster, cement or
	      similar finish.
	    - cable should be protected where it runs behind baseboards.
	    - Cable may not be run on the upper edge of ceiling joists
	      or the lower edges of rafters where the headroom is more
	      than 1m (39").

	Whenever BX cable is terminated at a box with a clamp, small
	plastic bushings must be inserted in the end of the cable to
	prevent the clamps forcing the sharp ends of the armor through
	the insulation.

	BX is sometimes a good idea in a work shop unless covered by
	solid wall coverings.

	In places where damage is more likely (like on the back wall of
	a garage ;-), you may be required to use conduit, a
	UL- (or CSA-) approved metal pipe.  You use various types of
	fittings to join the pipe or provide entrance/exit for the
	wire.

	Service entrances frequently use a plastic conduit.

	In damp places (eg: buried wiring to outdoor lighting) you will
	need special wire (eg: CEC NMW90, NEC UF).  NMW90 looks like
	very heavy-duty NMD90.  You will usually need short lengths of
	conduit where the wire enters/exits the ground.  [See underground
	wiring section.]

 	Thermoplastic sheath wire (such as NM, NMW etc.) should not be
 	exposed to direct sunlight unless explicitly approved for that
 	purpose.

	Many electrical codes do not permit the routing of wire through
	furnace ducts, including cold air return plenums constructed
	by metal sheeting enclosing joist spaces.   The reason for this
	is that if there's a fire, the ducting will spread toxic gasses
	from burning insulation very rapidly through the building.
	Teflon insulated wire is permitted in plenums in many areas.
	
 	Canada appears to use similar wire designations to the US,
 	except that Canadian wire designations usually include the
 	temperature rating in Celsius.  Eg: "AC90" versus "AC".
	In the US, NM-B is 90 degrees celcius.

	NOTE: local codes vary.  This is one of the items that changes
	most often.  Eg: Chicago codes require conduit *everywhere*.
	There are very different requirements for mobile homes.
	Check your local codes, *especially* if you're doing anything
	that's the slightest out of the ordinary.

	Wire selection table (incomplete - the real tables are enormous,
	uncommon wire types or applications omitted)

	Condition			Type	CEC	NEC

	Exposed/Concealed dry		plastic	NMD90	NM
					armor	AC90	AC
						TECK90

	Exposed/Concealed damp		plastic	NMD90	NMC
					armor	ACWU90
						TECK90

	Exposed/Concealed wet		plastic	NMWU90
					armor	ACWU90
						TECK90
	
	Exposed to weather		plastic	NMWU
						TW etc.
					armor	TECK90
	
	Direct earth burial/		plastic	NMWU*	UF
	Service entrance			RWU
						TWU
					armor	RA90
						TECK90
						ACWU90
	[* NMWU not for service entrance]

Subject: Should I use plastic or metal boxes?

	The NEC permits use of plastic boxes with non-metallic cable
	only.  The reasoning is simple -- with armored cable, the box
	itself provides ground conductor continuity.  U.S. plastic
	boxes don't use metal cable clamps.

	The CEC is slightly different.  The CEC never permits cable
	armor as a grounding conductor.  However, you must still
	provide ground continuity for metallic sheath.  The CEC also
	requires grounding of any metal cable clamps on plastic boxes.

	The advantage of plastic boxes is comparatively minor even for
	non-metallic sheathed cable -- you can avoid making one ground
	connection and they sometimes cost a little less.  On the other
	hand, plastic boxes are more vulnerable to impacts.  For
	exposed or shop wiring, metal boxes are probably better.

Subject: Junction box positioning?

	A junction box is a box used only for connecting wires together.

	Junction boxes must be located in such a way that they're accessible
	later.  Ie: not buried under plaster.  Excessive use of junction
	boxes is often a sign of sloppy installation, and inspectors may
	get nasty.

Subject: Can I install a replacement light fixture?

	In general, one can replace fixtures freely, subject to a few
	caveats.  First, of course, one should check the amperage
	rating of the circuit.  If your heart is set on installing half
	a dozen 500 watt floodlights, you may need to run a new wire
	back to the panel box.  But there are some more subtle
	constraints as well.  For example, older house
	wiring doesn't have high-temperature insulation.  The excess
	heat generated by a ceiling-mounted lamp can and will cause the
	insulation to deteriorate and crack, with obvious bad results.
	Some newer fixtures are specifically marked for high
	temperature wire only.  (You may find, in fact, that your
	ceiling wiring already has this problem, in which case
	replacing any devices is a real adventure.)

	Other concerns include providing a suitable ground for some
	fluorescent fixtures, and making sure that the ceiling box and
	its mounting are strong enough to support the weight of a heavy
	chandelier or ceiling fan.  You may need to install a new box
	specifically listed for this purpose.  A 2x4 across the ceiling
	joists makes a good support.  Metal brackets are also available
	that can be fished into ceilings thru the junction box hole and
	mounted between the joists.

	There are special rules for recessed light fixtures such as
	"pot" lamps or heat lamps.  When these are installed in insulated
	ceilings, they can present a very substantial fire hazard.
	The CEC provides for the installation of pot lamps in insulated
	ceilings, provided that the fixture is boxed in a "coffin" (usually
	8'x16"x12" - made by making a pair of joists 12" high, and covering
	with plywood) that doesn't have any insulation.  (Yes, that's 8 *feet*
	long)

	NEC rules are somewhat less stringent.  They require at least 3"
	clearance between the fixture and any sort of thermal insulation.
	The rules also say that one should not obstruct free air movement,
	which means that a CEC-style ``coffin'' might be worthwhile.
	Presumably, that's up to the local inspector.  [The CEC doesn't
	actually mandate the coffin per-se, this seems to be an inspector
	requirement to make absolutely certain that the fixture can't get
	accidentally buried in insulation.  Ie: if you have insulation blown
	in later.]

	There are now fixtures that contain integral thermal cutouts and
	fairly large cases that can be buried directly in insulation.  They are
	usually limited to 75 watt bulbs, and are unfortunately, somewhat
	more expensive than the older types.  Before you use them, you should
	ensure that they have explicit UL or CSA approval for such uses.
	Follow the installation instructions carefully; the prescribed location
	for the sensor can vary.

	There does not yet appear to be a heat lamp fixture that is approved
	for use in insulation.  The "coffin" appears the only legal approach.

Subject: What does it mean when the lights brighten when a motor starts?

	This usually means that the neutral wire in the panel is
	loose.  Depending on the load balance, one hot wire may end up
	being more than 110V, and the other less than 110V, with
	respect to ground.  This is a very hazardous situation - it can
	destroy your electronic equipment, possibly start fires, and in
	some situations electrocute you (ie: some US jurisdictions
	require the stove frame connected to neutral).

	If this happens, contact your electrical authority immediately
	and have them come and check out the problem.

	Note: a brief (< 1 second) brightening is sometimes normal with
	lighting and motors on the same 220V with neutral circuit.  A
	loose main panel neutral will usually show increased brightness
	far longer than one second.  In case of doubt, get help.

Subject: What is 3 phase power?  Should I use it?  Can I get it in my house?

	Three phase power has three "hot" wires, 120 degrees out of
	phase with each other.  These are usually used for large motors
	because it is more "efficient", provides a bit more starting torque,
	and because the motors are simpler and hence cheaper.

	You're most likely to encounter a 3 phase circuit that shows
	110 volts between any hot and ground, and 208 volts between
	any two hots.  The latter shows the difference between a normal
	220V/110V common neutral circuit, which is 240 volts between the
	two hots.  There are 3 phase circuits with different voltages.

	Bringing in a 3 phase feed to your house is usually
	ridiculously expensive, or impossible.  If the equipment you
	want to run has a standard motor mount, it is *MUCH* cheaper to
	buy a new 110V or 220V motor for it.  In some cases it is
	possible to run 3 phase equipment on ordinary power if you have
	a "capacitor start" unit, or use a larger motor as a
	(auto-)generator.  These are tricky, but are a good solution if
	the motor is non-standard size, or too expensive or too big to
	replace.  The Taunton Press book ``The Small Shop'' has an
	article on how to do this if you must.

	Note that you lose any possible electrical efficiency by using
	such a converter.  The laws of thermodynamics guarantee that.

Subject: Is it better to run motors at 110 or 220?

	Theoretically, it doesn't make any difference.  However, there
	is a difference is the amount of power lost in the supply
	wiring.  All things being equal, a 220V motor will lose 4 times
	less power in the house wiring than a 110V motor.  This also
	means that the startup surge loss will be less, and the motor
	will get to speed quicker.  And in some circumstances, the
	smaller power loss will lead to longer motor life.

	This is usually irrelevant unless the supply wires are more
	than 50 feet long.

Subject: What is this nonsense about 3HP on 110V 15A circuits?

	It is a universal physical law that 1 HP is equal to 746
	watts.  Given heating loss, power factor and other inefficiencies,
	it is usually best to consider 1 HP is going to need 1000-1200
	watts.  A 110V 15A circuit can only deliver 1850 watts to a motor,
	so it cannot possibly be more than approximately 2 HP.  Given rational
	efficiency factors, 1.5HP is more like it.

	Some equipment manufacturers (Sears in particular, most router
	manufacturers in general ;-) advertise a HP rating that is far
	in excess of what is possible.  They are giving you a "stall
	horsepower" or similar.  That means the power is measured when
	the motor is just about to stop turning because of the load.
	What they don't mention is that if you kept it in that
	condition for more than a few seconds hopefully your breaker
	will trip, otherwise the motor will melt -- it's drawing far
	more current than it can continuously.

	When comparing motors, compare the continuous horsepower.  This
	should be on the motor nameplate.  If you can't find that figure,
	check the amperage rating, which is always present.

Subject: How do I convert two prong receptacles to three prong?

	Older homes frequently have two-prong receptacles instead
	of the more modern three.  These receptacles have no safety
	ground, and the cabling usually has no ground wire.  Neither
	the NEC or CEC permits installing new 2 prong receptacles anymore.

	There are several different approaches to solving this:
	    1) If the wiring is done through conduit or BX, and the
	       conduit is continuous back to the panel, you can connect
	       the third prong of a new receptacle to the receptacle
	       box.  NEC mainly - CEC frowns on this practise.
	    2) If there is a copper cold water pipe going nearby, and
	       it's continuous to the main house ground point, you can
	       run a conductor to it from the third prong.
	    3) Run a ground conductor back to the main panel.
	    4) Easiest: install a GFCI receptacle.  The ground lug
	       should not be connected to anything, but the GFCI
	       protection itself will serve instead.  The GFCI
	       will also protect downstream (possibly also two prong
	       outlets).  If you do this to protect downstream outlets,
	       the grounds must not be connected together.  Since it
	       wouldn't be connected to a real ground, a wiring fault
	       could energize the cases of 3 prong devices connected
	       to other outlets.  Be sure, though, that there aren't
	       indirect ground plug connections, such as via the sheath
	       on BX cable.

	The CEC permits you to replace a two prong receptacle with a three
	prong if you fill the U ground with a non-conducting goop.
	Like caulking compound.  This is not permitted in the NEC.

Subject: Are you sure about GFCIs and ungrounded outlets?
	Should the test button work?

	We're sure about what the NEC and CEC say.  Remember, though,
	that your local codes may vary.  As for the TEST button -- there's
	a resistor connecting the LOAD side of the hot wire to the LINE
	side of the neutral wire when you press the TEST button.  Current
	through this resistor shows up as an imbalance, and trips the GFCI.
	This is a simple, passive, and reliable test, and doesn't require
	a real ground to work.  If your GFCI does not trip when you press
	the TEST button, it is very probably defective or miswired.  Again:
	if the test button doesn't work, something's broken, and potentially
	dangerous.  The problem should be corrected immediately.

	The instructions that come with some GFCIs specify that the ground
	wire must be connected.  We do not know why they say this.  The
	causes may be as mundane as an old instruction sheet, or with the
	formalities of UL or CSA listing -- perhaps the device was never
	tested without the ground wire being connected.  On the other hand,
	UL or CSA approval should only have been granted if the device
	behaves properly in *all* listed applications, including ungrounded
	outlet replacement.  (One of us called Leviton; their GFCIs are
	labeled for installation on grounded circuits only.  The technician
	was surprised to see that; he agreed that the NEC does not require
	it, and promised to investigate.)

Subject: How should I wire my shop?

	As with any other kind of wiring, you need enough power for all
	devices that will be on simultaneously.  The code specifies
	that you should stay under 80% of the nominal capacity of the
	circuit.  For typical home shop use, this means one circuit for
	the major power tools, and possibly one for a dust collector or
	shop vac.  Use at least 12 gauge wire -- many power tools have
	big motors, with a big start-up surge.  If you can, use 20 amp
	breakers (NEC), though CEC requires standard 20A receptacles
	which means you'd have to "replug" all your equipment.  Lights
	should either be on a circuit of their own -- and not shared
	with circuits in the rest of the house -- or be on at least two
	separate circuits.  The idea is that you want to avoid a
	situation where a blade is still spinning at several thousand
	RPM, while you're groping in the dark for the OFF switch.

	Do install lots of outlets.  It's easier to install them in the
	beginning, when you don't have to cut into an existing cable.
	It's useful if at least two circuits are accessible at each
	point, so you can run a shop vac or a compressor at the same
	time as the tool you really want.  But use metal boxes and
	plates, and maybe even metal-sheathed cable; you may have
	objects flying around at high speeds if something goes a bit
	wrong.

	Note that some jurisdictions have a "no horizontal wiring"
	rule in workshops or other unfinished areas that are used
	for working.  What this means is that all wiring must be
	run along structural members.  Ie: stapled to studs.

	Other possible shop circuits include heater circuits, 220V
	circuits for some large tools, and air compressor circuits.
	Don't overload circuits, and don't use extension cords if you
	can help it, unless they're rated for high currents.  (A coiled
	extension cord is not as safe as a straight length of wire of
	the same gauge.  Also, the insulation won't withstand as much
	heat, and heat dissipation is the critical issue.)

	If your shop is located at some remove from your main panel,
	you should probably install a subpanel, and derive your shop
	wiring from it.  If you have young children, you may want to
	equip this panel with a cut-off switch, and possibly a lock.
	If you want to install individual switches to ``safe''
	particular circuits, make sure you get ones rated high enough.
	For example, ordinary light switches are not safely able to
	handle the start-up surge generated by a table saw.  Buy
	``horsepower-rated'' switches instead.

	Finally, note that most home shops are in garages or unfinished
	basements; hence the NEC requirements for GFCIs apply.  And
	even if you ``know'' that you'd never use one of your shop
	outlets to run a lawn mower, the next owner of your house might
	have a different idea.

	Note: Fine Woodworking magazine often carries articles on shop
	wiring.  April 1992 is one place to start.

Subject: Underground Wiring

	You will need to prepare a trench to specifications, use
	special wire, protect the wire with conduit or special plastic
	tubing and possibly lumber (don't use creosoted lumber, it rots
	thermoplastic insulation and acts as a catalyst in the corrosion
	of lead).  The transition from in-house to underground wire is
	generally via conduit.  All outdoor boxes must be specifically
	listed for the purpose, and contain the appropriate gaskets,
	fittings, etc.  If the location of the box is subject to immersion
	in water, a more serious style of water-proof box is needed.  And
	of course, don't forget the GFCIs.

	The required depths and other details vary from jurisdiction to
	jurisdiction, so we suggest you consult your inspector about
	your specific situation.

	A hint: buy a roll of bright yellow tape that says "buried power
	line" and bury it a few inches above where the wire has been placed.

Subject: Aluminum wiring

	During the 1970's, aluminum (instead of copper) wiring became
	quite popular and was extensively used.  Since that time,
	aluminum wiring has been implicated in a number of house fires,
	and most jurisdictions no longer permit it in new installations.
	We recommend, even if you're allowed to, that do not use it for new
	wiring.

	But don't panic if your house has aluminum wiring.  Aluminum
	wiring, when properly installed, can be just as safe as copper.
	Aluminum wiring is, however, very unforgiving of improper
	installation.  We will cover a bit of the theory behind potential
	problems, and what you can do to make your wiring safe.

	The main problem with aluminum wiring is a phenomenon known as
	"cold creep".  When aluminum wiring warms up, it expands.  When
	it cools down, it contracts.  Unlike copper, when aluminum goes
	through a number of warm/cool cycles it loses a bit of tightness each
	time.  To make the problem worse, aluminum oxidises, or corrodes
	when in contact with certain types of metal, so the resistance
	of the connection goes up.  Which causes it to heat up and corrode/
	oxidize still more.  Eventually the wire may start getting very hot,
	melt the insulation or fixture it's attached to, and possibly even
	cause a fire.

	Since people usually encounter aluminum wiring when they move
	into a house built during the 70's, we will cover basic points of
	safe aluminum wiring.  We suggest that, if you're considering purchasing
	a home with aluminum wiring, or have discovered it later, that you
	hire a licensed electrician or inspector to check over the wiring
	for the following things:

	    1) Fixtures (eg: outlets and switches) directly attached to
	       aluminum wiring should be rated for it.  The device will
	       be stamped with "Al/Cu" or "CO/ALR".  The latter supersedes
	       the former, but both are safe.   These fixtures are somewhat
	       more expensive than the ordinary ones.

	    2) Wires should be properly connected (at least 3/4 way around
	       the screw in a clockwise direction).  Connections should be
	       tight.  While repeated tightening of the screws can make the
	       problem worse, during the inspection it would pay off to snug
	       up each connection.

	       Note that aluminum wiring is still often used for the
	       main service entrance cable.  It should be inspected.

	    3) "push-in" terminals are an extreme hazard with aluminum wire.
	       Any connections using push-in terminals should be redone with
	       the proper screw connections immediately.

	    4) There should be no signs of overheating: darkened connections,
	       melted insulation, or "baked" fixtures.  Any such damage should
	       be repaired.
	    
	    5) Connections between aluminum and copper wire need to be
	       handled specially.  Current Canadian codes require that the
	       wire nut used must be specially marked for connecting
	       aluminum to copper.  The NEC requires that the wire be
	       connected together using special crimp devices, with an
	       anti-oxidant grease.  The tools and materials for the latter
	       are quite expensive - not practical to do it yourself unless
	       you can rent the tool.

	    6) Any non-rated receptacle can be connected to aluminum wiring
	       by means of a short copper "pigtail".  See (5) above.
	    
	    7) Shows reasonable workmanship: neat wiring, properly stripped
	       (not nicked) wire etc.
    
	If, when considering purchasing a home, an inspection of the wiring
	shows no problems or only one or two, we believe that you can consider
	the wiring safe.  If there are signs of problems in many places,
	we suggest you look elsewhere.  If the wrong receptacles are used,
	you can replace them with the proper type, or use pigtails - having
	this professionally done can range from $3 to $10 per receptacle/switch.
	You can do this yourself too.

Subject: I'm buying a house!  What should I do?

	Congratulations.  But...  It's generally a good idea to hire
	an inspector to look through the house for hidden gotchas.
	Not just for wiring, but plumbing and structural as well.  If an
	inspection of the wiring shows no problems or only one or two minor
	ones, we believe that you can consider the wiring safe (after any
	minor problems are fixed).  If there are signs of problems in many
	places, we suggest you look elsewhere.

	Here's some hints on what to look for:

	Obvious non-code wiring can include:

		- Zip cord wiring, either concealed or nailed to walls
		- Hot wiring on the identified (neutral) conductor without
		  proper marking.
		- Ungrounded grounding outlets (except when downstream of
		  a GFCI)
		- Splices hanging in mid-air (other than proper knob-and-tube)
		- Switched neutrals
		- Unsecured Romex swinging about like grapevines

	Certain wiring practises that are actually to code (or were at one
	time) sometimes reveal DIY wiring that may have hidden violations:

		- Switches that seem to control nothing (abandoned, perhaps
		   not properly terminated wiring)
		- A wall switch that shuts off a group of lights that are
		  separately controlled by other wall switches.  (except when
		  it's *really* convenient ;-)
		- Switches and outlets in bizarre locations
		- Great numbers of junction boxes without outlets or lamps
		- Junction boxes with great numbers of wires going into them
		- Wiring that passes through a closet instead of a wall or
		  ceiling
		- Backwrapped grounding wires

Subject: What is this weird stuff?  Old style wiring
	
	In the years since Edison "invented" electricity, several different
	wiring "styles" have come and gone.  When you buy an older home you
	may encounter some of this stuff.  This section describes the old 
	methods, and some of their idiosyncrasies.

	The oldest wiring system you're likely to encounter is called
	"knob and tube" (K&T).  It is made up of individual conductors with
	a cloth insulation.  The wires are run along side structural
	members (eg: joists or studs) using ceramic stand-offs (knobs).
	Wire is run through structural members using ceramic tubes.  Connections
	were made by twisting the wire together, soldering, and wrapping
	with tape.  Since the hot and neutral were run separately,
	the wiring tends to be rather confusing.  A neutral often runs
	down the centre of each room, with "taps" off to each fixture.
	The hot wire tended to run from one fixture to the next.  In some
	cases K&T isn't colour-coded, so the neutral is often the same
	colour as the hot wires.

	You'll see K&T in homes built as late as the 40's.

	Comments on K&T:

		- the people installing K&T were pretty paranoid about
		  electricity, so the workmanship tends to be pretty good.
		- The wire, insulation and insulators tend to stand up
		  very well.  Most K&T I've seen, for example, is in
		  quite good condition.
		- No grounding.  Grounding is usually difficult to install.
		- boxes are small.  Receptacle replacement (particularly with
		  GFCI) can be difficult.  No bushing on boxes either,
		  so wiring changes need special attention to box entry.
		- Sometimes the neutral isn't balanced very well between
		  separately hot circuits, so it is sometimes possible to
		  overload the neutral without exceeding the fusing on
		  any circuit.
		- Building code does not permit insulation in walls
		  that contain K&T.
		- Connection to existing K&T from new circuits can be
		  tricky.  Consult your inspector.
		- Modern wiring practise requires considerably more
		  outlets to be installed than K&T systems did.
	
	Since K&T tends to be in pretty decent condition it generally isn't
	necessary to replace it simply because it's K&T.  What you should
	watch out for is renovations that have interfered with it and
	be cautious about circuit loading.  In many cases it's perfectly
	reasonable to leave existing K&T alone, and add new fixtures on
	new circuits using modern techniques.
	
	After K&T, they invented multi-conductor cable.  The first type
	you will see is roughly a cloth and varnish insulation.  It looks
	much like the romex cable of the last decade or two.  This stuff was
	used in the 40's and 50's.  Again, no grounding conductor.
	It was installed much like modern wiring.  Its major drawback
	is that this type of insulation embrittles.  We've seen whole
	systems where the insulation would fracture and fall off at
	a touch.  BX cable of the same vintage has similar problems.

	This stuff is very fragile, and becomes rather hazardous if
	the wires become bare.  This wiring should be left untouched as
	much as possible - whenever an opportunity arises, replace it.
	A simple receptacle or switch replacement can turn into a several
	hour long frustrating fight with electrical tape or heat-shrink
	tubing.

	After this wiring technique, the more modern romex was invented.
	It's almost a asphalt impregnated cloth.  Often a bit sticky.
	This stuff stands up reasonably well and doesn't present a hazard
	and is reasonably easy to work with.  It does not need to be
	replaced - it should be considered as safe as the "modern" stuff -
	thermoplastic insulation wire.  Just don't abuse it too much.

Subject: Where do I buy stuff?

	Try to find a proper electrical supply outlet near you.  Their
	prices will often be considerably better than chain hardware stores or
	DIY centres, have better quality materials, have wider variety
	including the "odd" stuff, and have people behind the counter that
	know what you're talking about.  Cultivate friendly knowledgeable
	sales people.  They'll give you much valuable information.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
Ferret list: ferret-request@ferret.ocunix.on.ca

Newsgroup: sci.electronics
document_id: 53570
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - SunConnect ICNC)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>, swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) writes:
> 
> 
> I really don't know where to post this question so I figured that
> this board would be most appropriate.
> I was wondering about those massive concrete cylinders that
> are ever present at nuclear poer sites. They look like cylinders
> that have been pinched in the middle. Does anybody know what the
> actual purpose of those things are?. I hear that they're called
> 'Cooling Towers' but what the heck do they cool?

Water. Nuclear stations don't generate electricity directly from the
reactor, they use the reactor to generate heat. The heat is then used to
heat water just as in a conventional oil or coal station, and the
resultant steam drives the turbines.

The cooling towers are used to cool the steam and recondense it into water
to continue the cycle

Steve

-- 
Steve McKinty
Sun Microsystems ICNC
38240 Meylan, France
email: smckinty@france.sun.com	   BIX: smckinty

Newsgroup: sci.electronics
document_id: 53571
From: markz@ssc.com (Mark Zenier)
Subject: Re: Trace size for a 15 Amp supply

R.G. Keen (rg@futserv.austin.ibm.com) wrote:
: A quick and dirty way to get higher current carrying capacity
: on PC board traces for one- or few-of-a-kind boards is to
: strip some #14 Romex house wiring cable to bare copper, form
: the bare copper to follow the trace, and solder it down.

And if it's not quick and dirty, you can get bus bars that
are stamped out with leads that insert in the PC board.

Mark Zenier  markz@ssc.wa.com  markz@ssc.com  



Newsgroup: sci.electronics
document_id: 53572
From: craig@toontown.ColumbiaSC.NCR.COM (Craig S. Williamson)
Subject: Re: Looking for a good Spice book

In article <canright.734829385@convex.com> canright@convex.com (Robert Canright) writes:
|you might try
|"Computer-Aided Circuit Analysis Using SPICE" by Walter Banzhaf,
|at bookstores, paperback, ~$33, lots of examples. Dr. Banzhaf
|is a teacher.

Is there another book.  I have this one and don't find it helpfull in 
learning Spice.  It would make a good reference book but I found it lacking
for learning Spice.  Are there any others?

Craig

-- 
                                             "You took the bull by the horns
-Craig Williamson                              and stepped in something good."
 Craig.Williamson@ColumbiaSC.NCR.COM               - Balki Bartokomas
 craig@toontown.ColumbiaSC.NCR.COM (home)                 Perfect Strangers

Newsgroup: sci.electronics
document_id: 53573
From: heke@stekt.oulu.fi (Heikki Paananen)
Subject: Re: How do DI boxes work?

In article <LANCER.93Apr15150228@oconnor.WPI.EDU> lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:

>   I'm doing sound for a couple of bands around here and we need Direct
>   Input boxes for the keyboards.  These are the little boxes that take a
>   line level out of the keyboard and transform it into low-Z for the run
>   to the mixer.  Sadly they cost like $50 (or more) each and I'm going
>   to need like 5 or 10 of them!  I looked inside one (belonging to
>   another band) and it looks like just a transformer.  Does anyone have
>   any plans for building them?  Perhaps in Anderton's "Electronic
>   Projects for Musicians" book (which I am having a hell of a time
>   tracking down...)?

An Easy way to solve the problem is to use two op-amps to form the
balanced low-Z output, but this solution does not provide any
galvanic isolation between keyboard (or whatever plugged) and
mixer. If no tight requiremets are demanded and some hum, snap,
crackle and pop sounds (formed by ground loops) can be tolerated,
the op-amp solution is just what you are looking for! (It is
cheap...somewhat $10/DI-box).
Not sure, but Craig Anderton did introduce one DI-box project
in Guitar Player mag years ago (transformerless).....

>   Thanks a lot!

Hope this helps. Email, if more details wanted....

>   - lancer@wpi.wpi.edu -                    - 0{{  MoDiMiDoFrSaSo: -
>   -   Mein Kopf ist ein Labyrinth, mein Leben ist ein Minenfeld    -

-----------------------------------------------------------------------
Heikki Paananen                           heke@stekt.oulu.fi
The University of Oulu                  
Department of electrical engineering      -Just a student
Finland
-----------------------------------------------------------------------
               Home is where the heart lies,
            but if the heart lies where is home?
                                           -Fish

Newsgroup: sci.electronics
document_id: 53574
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: How do DI boxes work?

lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:


>I'm doing sound for a couple of bands around here and we need Direct
>Input boxes for the keyboards.  These are the little boxes that take a
>line level out of the keyboard and transform it into low-Z for the run
>to the mixer.  Sadly they cost like $50 (or more) each and I'm going

This is indeed one function, but more sophisticated ones do level control
and ground-lift (separating the keyboard and mixer earths) aswell.

>to need like 5 or 10 of them!  I looked inside one (belonging to
>another band) and it looks like just a transformer.  Does anyone have

Simple ones are just that - a transformer. A decent quality audio trans-
former will cost most of that $50. They are wired thus...


       HOT   --------------|  |----------------- HOT
                           )||(
     Input from            )||(                Balanced out to mixer
     Keyboard              )||(
                           |  |----------------- COLD
                           |
       GND   --------------|-------------------- GND

The ground-lift switch disconnects the GND line from the mixer. The
transformer ratio depends on the precise application, but around 10:1
turns ratio may be a good place to start.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
document_id: 53575
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

davidj@rahul.net (David Josephson) writes:

>In <C5JJJ2.1tF@cmcl2.nyu.edu> ali@cns.nyu.edu (Alan Macaluso) writes:

>>I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

>>Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.

>Without doing anything really tricky, the best I've seen is the
>Burr-Brown INA103. Their databook shows a good application of this
>chip as a phantom power mic pre.

I've had very good results from the SSM2016 from PMI (part of Analogue
Devices). They have also now introduced the SSM2017 which looks good on
paper, but which I haven't tried yet.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
document_id: 53576
From: dwo@zerberus.gud.siemens.co.at (F.Dwo)
Subject: DSP 56001

Hi !!!

Is there somebody using a 56001 DSP from Motorola ???
I am searching for programms concerning audio effects.
I built a 4 channel mixer (4ADC + 1DSP) for audio signals.
I built some digital filters and echos, but now i want to
include some effects like HARMONIC Equalizer or chorus.
The problem is, I dont know how these effects work (so I cant
write a programm).
So if someone has programms or just knows how such effects work,
please contact me in the newsgroup or via e-mail.
(Also if there are books about this problem)

Thanks in advance
(DWO)

Newsgroup: sci.electronics
document_id: 53577
Subject: Re: Cable TVI interference
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1qevrf$4t@hpscit.sc.hp.com>  writes:
> 
> As is typical nowadaze, you will probably have to do somebody else's job
> for them. Although this shouldn't be needed, you might take a few minutes
> to wander around the neighborhood with an HT sniffing for cable leakage
> on your freq. after shutting down your system for a while. 
> 
> If you are fortunate enough to the find the hole, call the cable company and
> get the highest link in the chain of command you can. Explain the problem,
> whose job it really is to maintain THEIR equipment, and how much of a nice
> guy you are to have tracked down THEIR problem for them.
> 
> You may have been lucky and made a new contact that could be helpful in the
> future.
> 
> You should always try the 'honey' approach before bringing out the
> Jack Nicholson impressions.....  >:-)
> 
> This has worked for me in the past with the power company when tring to 
> find loose/noisy high voltage lines/hardware. Only once did I have to
> tell them I was narrowing the problem down to a specific pole by bumping
> a whole line of poles with my car. Got 'em out there THAT NIGHT. And, they
> didn't have to meet Jack!
> 
> As a disclaimer, THEIR method for finding loose hardware was usually
> whacking the poles with a huge sledgehammer after their high tech arc-
> finding 'scope couldn't find the problem.
> 
> 
> 
> Bill
> wb6 rotten zucchini garden

Here in switzerland, the situation is exactly the same. The cable tv companies  
even tried to stop amateur radio in switzerland in the beginning of cable  
tv(they seem to be too stupid to know anything about international frequency  
conferences or so). Even today, they use the cheapest possible coax running  
into problems they can't solve anymore. As Bill noted, the only way is to look  
for a solution with the neighbours *BEFORE* calling for the cable tv guys or  
the fcc. The chance to find neighbours with some sense for reason is by far  
bigger than with these people (especially the first ones). As anywhere in an  
administration people don't like, if You tell them to work for the money they  
get...
The problem is, that radio amateurs don't have the power to put trough their  
rights in all cases. So let's hope they start soon with optical fibers and get  
out of our freqencies.


Cheers   Robert  (HB9NBY)
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
document_id: 53578
From: mkaschke@oasys.dt.navy.mil (Martin Kaschke)
Subject: 4-Band Equalizer


    I was wondering if anyone out there in net-land knew of a SIMPLE
way to make a 4-band equalizer (single channel).  I need it to accept
LINE inputs (tape deck, CD player, etc.) and output to the same! So
input impedance should equal output impedance.  Also, since I am driving
a line, I would need 1 volt p-p output.  Final requirement is that I
can either:
	      1. Control it digitally
			OR
	      2. Control it easily, or with few resistors

FINALLY - If anyone knows of any FILTER or EQUALIZER chips, that might
be useful, please let me know. (I have seen a couple of them from NATIONAL,
and MAXIM).  Thanks in advance,
				  Martin

Newsgroup: sci.electronics
document_id: 53579
From: Arthur_Noguerola@vos.stratus.com
Subject: Re: Adcom cheap products?

In article <C5K177.BoK@world.std.com> rogerw@world.std.com (Roger A Williams) wrote:  
>mdonahue@amiganet.chi.il.us (Mike Donahue) writes: 
> 
> 
>>I do NOT know much about Adcom Mobil Audio products, but I DO know for a fact 
>>that ADCOM does NOT make its own "High End" Home Audio Equptment and that 80%+ 
>>of it comes directly out of Tiawan... 
> 
>Like most high-volume manufacturers, Adcom has most of its PC boards 
>assembled off-shore (in their case, mostly in the far east).  Final 
>assembly _and testing_ are done in East Brunswick. 
> 

          and of course you older folks on the net will remember 
          way back when Adcom got its RAVE reviews and kudos (ca 
          1985  or  so)  their  555 amp and preamp WERE not only 
          designed here but built here in  the  USA.  then  they 
          went  to  mexico  and then to taiwan right after their 
          sales  skyrocketed   because   of   their   Stereopile 
          review!!!  if you have units that old look for MADE IN 
          --- stickers on your unit. 


Newsgroup: sci.electronics
document_id: 53580
From: baldur@rsp.is (Baldur Thorgilsson)
Subject: receiver system


Dear Netters
I want to send EMG-signals from a running person to a computer. 
Each signal is 4KHz wide and there is up to 30 of them on each
running person. The signal is only to be sent over a few hundred 
meters. It seems to me that the frequency intended for this use is
about 150MHz and about 440MHz.
To make the transmitters as light as possible I suppose it will be best 
the to send the signals in an analog form. As this application is rather 
specialized I do not expect to be able to buy the exact transmitter-
units i need.
On the other hand I imagine that I can buy the receiver somewhere. I 
need a multichannel (up to 30 channels) receiver or 30 complete  
receivers in some rack system where one can add as many receivers 
as needed in the particular case.
DO ANYBODY KNOW IF THERE IS EXISTING SUCH RECEIVER 
SYSTEM ON THE MARKET?

baldur@rsp.is     (TF3BP) (please respond by email rather than nn)

Newsgroup: sci.electronics
document_id: 53581
From: then@snakemail.hut.fi (Tomi  H Engdahl)
Subject: Re: Telephone on hook/off hok ok circuit ~

In article <1ptolq$p7e@werple.apana.org.au> petert@zikzak.apana.org.au (Peter T.) writes:

>Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 10V.
>How about an LED in series with a zener say around 30V.
>On-hook = LED on
>Off-hook = LED off.
>Would this work? If anyone tries/tried it, please let me know.

Not recommended. Your circuit would take too much current, when
telephone is on-hook. Telephone company does not like it.


--
Tomi.Engdahl@hut.fi  !  LOWERY'S LAW:
then@niksula.hut.fi  !  "If it jams - force it. If it breaks,
                     !   it needed replacing anyway." 
* This text is provided "as is" without any express or implied warranty *

Newsgroup: sci.electronics
document_id: 53582
From: webb@itu1 (90-29265  Webber  AH)
Subject: Re: Adcom cheap products?

: >I want to upgrade my system and was thinking of buying Adcom seperates.
: >I have heard from alot of people, though, that Adcom sounds great but
: >that the components are made cheaply and therefore won't last very long.
: >The time estimates I've heard are like only 3 or 4 years.  Is this true?

I own the Adcom 60W power amp.  As far as I'm concerned, there's no
  amp which can touch it at the price range.
The build quality is very impressive and is far superior to other 
  amps in the price range.  The whole amplifier is extremely solid
  with massive heat sinks and very solid casing.
If you open the amp up, there are only very good quality components 
  in and the amp seems to be designed extremely well.  Perfect
  symmetry for both channels and TWO transformers - one for each
  channel.  The binding posts on the back of the amplifier are
  virtually the same as those on the Classe model 70 ie. very good.

I was also sceptical about the amps being built in the far-east
  or where-ever.  But if you look in the amp and see what components
  they use and how it was designed, you can easily see why the
  amplifiers sound so brilliant.
I cannot see why people say the amplifier won't last - not with
  those quality components inside.  Sure the amp runs very fairly
  hot - but that's how you get an amp to sound incredibly good.

My last point, I recently auditioned the Adcom preamp something like
  the 545 or something.  It was two years old and it still sounded
  like new.

If you build an amplifier decently, like the Adcom's, they will
  sound brilliant and last a long time - period.

Just my thoughts, but then - I do own one of Adcom's amps.

--
***********************************************************************
**    Alan Webber                                                    **
**                      webb@itu1.sun.ac.za                          **
**                      webb@itu2.sun.ac.za                          **
**                                                                   **
** The path you tread is narrow and the drop is sheer and very high  **
** The ravens all are watching from a vantage point near by          **
** Apprehension creeping like a choo-train up your spine             **
** Will the tightrope reach the end; will the final couplet rhyme    **
***********************************************************************

Newsgroup: sci.electronics
document_id: 53583
From: mabbot@stellenbos.csir.co.za (Mike Abbot)
Subject: High level language compilers for uControllers ?

Howdy chaps

Has anybody got any pointers to good C, Pascal, etc compilers for 
microcontrollers, shareware or otherwise ?

My specific need is for 8051 C, but if the responses are many and varied I 
will post a summary.

Cheers
Mike


Mike Abbott	mabbot@stellenbos.csir.co.za
Cape Town	mabbot@fred.csir.co.za
South Africa

Newsgroup: sci.electronics
document_id: 53584
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Illusion

I missed the first article[s] on this line due to not having a
chance to read the news for a couple of days...

The idea is commercialized in at least one product, the Private
Eye.  That's a small cube-shaped device that the user straps around
the head similar to a sweat band.  There is a boom that comes from
the side on which the device is mounted so that it is positioned
in front of the user's eye.

The Private Eye we had here for evaluation was Hercules-MDA
compatible.  The innards are a row (~400 LEDs) that are swept up
and down by a galvonometer-like movement.  The result is that the
sweeping LED bar forms a fused raster.  There is a virtual image
projected in front of the user that the visual system tends to fuse
with the background.

I didn't like the device very much.  I found it easiest to use if I
looked at a blank white wall.  I had problems with focus tracking
if I glanced down to look at my keyboard for an out-of-the-way key.
The unit also emitted a soft buzz and vibration which I found
annoying.  Some people didn't seem to mind the buzz.  Properly
used, however, the image clarity was quite crisp.

I don't know if the company has taken the technology any further in
the last year or two, but it did seem to have promise.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53585
From: Michael_LaBella@vos.stratus.com
Subject: Re: Adcom cheap products?


>Off-shore assembly is one reason that Adcom is able to make products 
>that perform as well as those from people like Audio Research and Van 
>Alstine (and better than Hafler and Forte'), but at a much lower cost. 

How do you spell "tuna helper" ? 

I gather by off-shore assembly you mean that adcoms are built by 
blue-fin tuna's who are into that squid-fi sound?  (I agree on that one). 
My Adcom 555 preamp did sound better after installing the famous  
"running the chips class "A" resistor mod", and replacing the metal 
bottom cover with plexiglass,, too bad the factory could not make em sound 
better,, but better sound, unfortunately, does not appear to be a priority 
with Adcom, else the mods would neither have been necessary, nor would they 
have improved what was already touted as superlative state-o-d-art le'sound. 
I really want to hear from all those people out there who have traded up  
from an sp9II (even an sp3a!) to a GFP-555/etc., or maybe from those that 
have dumped their forte' amps for a GFA-555/etc....  



Newsgroup: sci.electronics
document_id: 53586
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Adcom cheap products?

I have an Adcom GFA-555 that I got in 1985.  There certainly isn't
anything magic about it.  The components used are decent, but
nothing uncommon with respect to consumer grade components.

The GFA-555 is a nice piece of equipment.  I'm glad that Adcom had
the guts to not over-do the packaging.  It irks me when I see
audiophile oriented equipment whose case and heat sinks probably
cost much more and receive more attention than the electronics they
are supposed to serve.

I don't see any big deal about the geographic region in which
something is assembled.  This is especially true for something as
low-technology as a GFA-555.

I'd hope that a GFA-545 would still work well after several years.
Except under conditions of extreme abuse, there isn't much there to
go wrong.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53587
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1993Apr15.103953.66252@cc.usu.edu>  writes:
> In article <C5Hs5J.AG7@bcstec.ca.boeing.com>, rgc3679@bcstec.ca.boeing.com  
(Robert G. Carpenter) writes:
> 
> |> It seems reasonable to me that a microwave transmitter-receiver setup  
could 
> |> do the job. For example, say you want to map an acre lot, it'd be  
convenient
> |> to place MW transmitters around the lot's periphery (either 2 or 3) and  
then
> |> carry a hand-held recorder and walk to a point on the lot, press a button  
and
> |> the coords of the recorder's location is stored as digital data.
> |> 
> |> What's the chance of this working? Any systems like this already exist?
> |> What kind of accuracy could you expect? What would something like this
> |> cost to prototype? Is there a better alternative than microwaves?
> 
> Of course you could develope this system, but there is already a system  
called Global
> Positioning Satellites.  It gives three dimensional coordinates anywhere on  
earth. 
> Many surveyors use this system with a differential receiver/transmitter to  
get
> coordinates within centimeters.  Basic receivers with resolution of a few  
meters (on
> a good day) are available from many sources.
> 
> 
> -- 
> WMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMW
> 
>   \_      \_  \_\_\_    \_\_\_               Weston R Beal
>    \_      \_  \_    \_  \_    \_         sldf3@sol.ee.usu.edu
>     \_  \_  \_  \_\_\_    \_\_\_            sldf3@cc.usu.edu
>      \_\_  \_\_  \_  \_    \_    \_       Electrical Engineer
>       \_      \_  \_    \_  \_\_\_       Utah State University
> 
>   "That's the wonderful thing about crayons; they can take you to
>    more places than a starship can."    - Guinon
> 
> 

Thought it means Global Positioning System. There are two precision levels, one  
for army applications (killing has to be very accurate today) and one for civil  
ones. The civil precision is about 20 to 30m (correct me, if I'm wrong),  
though, it may be insufficiant for mapping buildings. But there is a way with  
an additional reference point (e.g. one fixed GPS system in a house) to get the  
same high precision as the military version, but it gets pretty complicated  
then. If You use a microwave system (actually this means some type of radar),  
You need quite a lot of number crunching to get accurate vectorized data out of  
Your original signals. So the GPS system seems to be the better (and running)  
idea for Your application(there have been discussions in this newsgroup, don't  
know of an address anymore).

Cheers    Robert   (HB9NBY) 
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
document_id: 53588
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: mysterious TV problem -- source?

If the set is direct line powered, try checking the [likely to be
there] hybrid regulator module down stream from the 170 volt
supply.  Several sets I've looked at use a 135 volt regulator.  The
regulators have a tendency to short out, making the safety circuits
shut down the EHT supply section.

Try putting the set on a Variac or adjustable transformer and lower
the AC input voltage to the set to about 90 volts.  If the set
operates nromally, then you know you've got a shorted regulator.

There are myriad other areas for problems, but I've seen the one
above several times.  Also, if the set uses one, the trippler
module may be shot; that's fairly common.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53589
From: larryhsu@mtl.mit.edu (Lawrence Hsu)
Subject: Shrunken monitor window?

Does anyone know what causes the ever-growing black border around the
edges of my computer screen?  The growth has been gradual so I don't
know how long it's taken to get this bad.  I have a 19" DEC (?)
color monitor, maybe five years old, and the black border is about 1.1
inches on the left and right sides, about 1.75 inches on the bottom and
negligible at the top of the screen.  The only controls are
brightness knob, contrast knob, deGauss switch, and power switch.

Is there anything to be done, or are the monitor's days numbered?

Larry Hsu
larryhsu@mtl.mit.edu

Newsgroup: sci.electronics
document_id: 53590
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dumb Question: Function Generator

1)  Output offset:  Obtain the service manual for the oscilloscope
and adjust the internal output offset contorl.  There is virtual
certainty that there is an internal ajustment for the offset
control's zero detent position.

2)  Verify that the function generator is properly loaded.  Many
generators expect you to supply a 50 ohm load.  Go to a hamfest
flea market and scrounge around for a pass-through 50 ohm
terminator that has a male and female BNC (or whatever) connector
on it.  The calibrator on my Tektronix scope is designed to put out
.4v into a 1 meg load, but .1 volt into a 50 ohm load.  You may
also find that loading the output of the function generator also
reduces the harmonic distortion.

Build an attenuator.  You don't have to use (and I wouldn't want to
use) the input impedance of the device under test as part of the
voltage divider to drop the input test voltage.  Consider this:

------10K--------+---------? ohm ----
                 |
Gen            50 ohm            D.U.T.
(loaded)         |
-----------------+-------------------

Think about the ratio of 50/10K and then think about the accuracy
to which you can read voltages on your oscilloscope.  You can
virtually discount the loading of the D.U.T.  Also you have the
millivolt test generator you want.

Good luck,


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53591
From: seema@madvlsi.columbia.edu (Seema Varma)
Subject: IC Packages

Hi,
	I am looking for some help in choosing a package
for a high-speed silicon ADC (100Mhz) currently being 
fabricated. This is a PhD research project and I have to test
the chip at speed on a PCB. I expect to have roughly 100
packaged circuits and will do DC, low-speed and high-speed
testing using 3 different set-ups for the test chip.
 	
	I know for sure that a DIP will not work
(the long lead lines have too high an inductance).
Getting a custom-made package is too expensive, so
I am trying to choose between a flatpak and a
leadless chip carrier. The flatpack would be hard
to test since it has to be soldered on to the test
setup and I would spend loads of time soldering 
as I kept changing the test chip. The leadless chip
carrier sockets also have long lead lines and may
not work at high speeds.
 
	Does anyone out there have experience/knowledge
of this field ? I would greatly appreciate help! Any ideas/
names of companies manufacturing holders/sockets/packages
would help. 
 
P.S. The multi-layer fancy GaAs packages seem like a bit
of overkill(?)
	
 --- Seema Varma

Newsgroup: sci.electronics
document_id: 53592
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Just to complete that thought, the cooling towers cool water that
circulates through heat exchangers that recondense the turbine
exhaust back into feedwater for the heat exchangers that transfer
energy from the reactor's cooling circuit.


  |---------------|   |------turbine, etc---|  |---------|
  |                >   >                    >   >        .
reactor            <   <                    <   >        .
  |                >   >                    >   >        C. T.
  |---------------|    |--------------------|  |----------

The reactor has a closed loop circuit to prevent radioactive
contamination of the the turbine feedwater.

The cooling tower is a separate circuit to avoide contamination of
the turbine feedwater with atmospheric contamininats, etc.
Purifying boiler feedwater is important business at both fossil
fired and nuclear generation facilities.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53593
From: jmains@engr.latech.edu (John P. Mains)
Subject: Electrical Properties of ELASTOMERS


Hello,

I am looking for carbon-doped rubber.    Or an highly elastic material that changes its resistivity, or some
other electrical property when streched.

If you could email me any info you may have on material names or companies that make the stuff
it would be highly appreaciated.

Thanx
JP
Biomedical Engineering
Louisiana Tech University 

Newsgroup: sci.electronics
document_id: 53594
Subject: Re: Picking up cable tv with an aerial.
From: ganter@ifi.unibas.ch (Robert Ganter)

Great, the first advantage of cheap coax, I've ever heard.

Cheers   Robert  (HB9NBY)

--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
document_id: 53595
Subject: Re: What do Nuclear Site's Cooling Towers do?
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>  writes:
> 
> 
> I really don't know where to post this question so I figured that
> this board would be most appropriate.
> I was wondering about those massive concrete cylinders that
> are ever present at nuclear poer sites. They look like cylinders
> that have been pinched in the middle. Does anybody know what the
> actual purpose of those things are?. I hear that they're called
> 'Cooling Towers' but what the heck do they cool?
> I hope someone can help 
> 

This is definitely the wrong newsgroup for this, but never mind.
Any machine powered by heat (motor, steam- or gasturbine, steamengine,  
thermoelement,etc) work the better, the bigger the temperature difference  
between input and output is. Because You never get all thermic energy out of  
the powering medium (steam, burning gaz, etc), You have to eliminate the rest  
of the energy to keep the efficency high. A thermal electric power plant (coal,  
oil or atomic power) works just the same way. You heat water (steam) to power  
the turbine and generators. Because You don't get the whole energy out of the  
steam (efficency is never 100%) You have to cool down this steam again by  
something else. Most power plants use cooling towers for this purpose (some  
type of mega-refrigerator...). Others use water of a river (ecologically not  
unobjectionable). Got it ?

Cheers   Robert  (HB9NBY)
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
document_id: 53596
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Re: A question about 120V

>>SO..  Here's my question.  It seems to me that I'd have the
>>same electrical circuit if I hooked the neutral jumper from the
>>neutral over to the ground screw on new 'three prong' grounding
>>outlets. What's wrong with my reasoning here?

>First, go to the local hardware store and pick up a copy of "Wiring
>Simplified" by H.L. Richter.  Now if your house is wired with metal
>conduit, you don't need a seperate ground wire (assuming the house
>is wired correctly and the pipes are connected to a cold water
>pipe in your basement).  The outlets that have a neutral hooked to
>the ground screw seem wrong.  Anyone else think so?

Back in the 70's I was a service technician for a cash register company.
The cash registers used microprocessor circuits and back then they were
VERY susceptible to electrostatic discharge and line noise.  The biggest
problems came from outlets that were not properly grounded.

In almost every place we went to do an installation, we found outlets
with the ground connected to the neutral.  For 99.9% of the things you
can plug into one of these, they work fine.  For our cash registers they
were a nightmare -- line noise tended to scramble the memory
periodically.

With modern electronics using switching power supplies this should be
less of a problem.  Even the company I used to work for is no longer
recommending a dedicated line with a seperate ground for their
equipment.  I imagine if you check MOST household wiring you will find
that the ground and neutral are connected.  Although not ideal, it
should be o.k. for most applications.

---
 . SLMR 2.1 . My reality check just bounced.
                                
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
document_id: 53597
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Husky Programmer bits req'd

Help !! - I'm looking for a ISA driver card and driver software for a
Logical Devices Husky programmer (It aint mush good without these)
can anyone help with either of these items ?
cheers
Mike.

Newsgroup: sci.electronics
document_id: 53598
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: receiver system

One thing to consider is time division multiplexing the EMG
channels to reduce the number of RF carriers you have to generate.
If you multiplexed the EMG inputs at 10KHz, that would probably be
sufficient for most physiology studies (you'd have ~ 330 Hz per
channel sampling rate.)  That level of analog multiplexing should
be rather easy to accomplish.

Combining a lot of RF carriers is pretty tricky to do without
generating intermodulation.  A system to be carried by a runner is
in a fairly harsh environment and would probably be difficult to
keep balanced.

A commercial hand-held transciever could probably be employed with
a little modification to accomodate widening the bandwidth.
Obviously, this has to be done in accordance with whatever laws
govern the use of transeivers in your location.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53599
From: cam@castle.ed.ac.uk (Chris Malcolm)
Subject: CASIO SF7500 SERIAL LINK

The Casio 7500 lectric diary has a 3-wire serial interface with param
setting like RS232, for which one get a magic but expensive cable to
connect to a PC. Does anyone know the spec of this interface, e.g., it
needs inverting and boosting from CMOS signals to match RS232 lines?
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205

Newsgroup: sci.electronics
document_id: 53600
From: garyg@warren.mentorg.com (Gary Gendel)
Subject: Re: A question about 120VAC outlet wiring.

In article 1834@cmkrnl.com, jeh@cmkrnl.com writes:
>In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
>> SO..  Here's my question.  It seems to me that I'd have the
>> same electrical circuit if I hooked the jumper from the neutral
>> over to the ground screw on new 'three prong' grounding outlets.
>> What's wrong with my reasoning here?  
>
>What you CAN do if you want three-prong outlets without additional wiring is 
>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>depending on where you are putting your new outlet(s), a GFCI may be *required*.

You still need to supply a proper ground for a Ground Fault Circuit Interrupter!
So rewiring is still a part of this job, however, the ground may be connected to
a local earth ground, rather than back at the breaker box.

As Jamie said, GFCI devices are required by code in a number of places, most
notably: bathrooms, and outside the house.  I do suggest the use of GFCI outlets,
rather than the breakers.  You will end up with much less headaches.  Noise pickup
in long cable runs is sometimes enough to cause frequent tripping of the breakers.

GFCI devices do save lives, if you decide to install them, be sure to check them
regularly (using the test button).

Running the family business (electrical supplies and lighting) for many years, I
have seen too many seasoned electricians fried, because they forgot to double check
their common sense list.  Please exercise caution.
---
			Gary Gendel
Vice President:				Current consulting assignment:
Genashor Corp				Mentor Graphics Corporation
9 Piney Woods Drive			15 Independence Boulevard
Belle Mead, NJ 08502			Warren, NJ 07059

phone:	(908) 281-0164			phone:	(908) 604-0883
fax:	(908) 281-9607			email:	garyg@warren.mentorg.com








Newsgroup: sci.electronics
document_id: 53601
From: LLBGB@utxdp.dp.utexas.edu
Subject: chip / chipset for code 39 barcode?

Distribution: usa
Reply-To: lihan@ccwf.cc.utexas.edu

While I'm on the net bugging everyone, is there such a thing as a chip
or chipset to decode Code 39 barcode?  I ask for a couple of reasons --
mainly I want a reasonably compact encoding scheme to write information
on magstripe cards and Code 39 appears to be about right.  (If the 'right'
way to do it is something else, and it's reasonably easy, can someone let
me know?)

I might not get a chance to reply too quickly to this or my earlier post,
but I'll get to them within a couple days, I think ..

thanx everyone!  <BGB>  lihan@ccwf.cc.utexas.edu


Newsgroup: sci.electronics
document_id: 53602
From: donrm@sr.hp.com (Don Montgomery)
Subject: Radio Shack Battery of the Month Club


Radio Shack has canceled their "Battery of the Month" Club.  Does 
anyone know why?  

They say they'll honor existing cards in customer hands, but no new
cards will be issued.

Don Montgomery
donrm@sr.hp.com


Newsgroup: sci.electronics
document_id: 53603
From: johne@vcd.hp.com (John Eaton)
Subject: Re: What do Nuclear Site's Cooling Towers do?

-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:
: 
: 
: I really don't know where to post this question so I figured that
: this board would be most appropriate.
: I was wondering about those massive concrete cylinders that
: are ever present at nuclear poer sites. They look like cylinders
: that have been pinched in the middle. Does anybody know what the
: actual purpose of those things are?. I hear that they're called
: 'Cooling Towers' but what the heck do they cool?
: I hope someone can help 
:-----------------------
During the nuclear fission reaction the uranium fuel can get hot enough
to melt. When this happens the liquid uranium is pumped to the cooling
tower where it is sprayed into the air. Contact with the cool outside air
will condense the mist and it will fall back to the cooling tower floor.
There it is collected by a cleaning crew using shop vacs and is then
reformed into pellets for reactor use the next day.

Cooling towers are a lot taller than they really need to be. Power companies
are forced to make them that tall by some enviromental law that requires the
raw uranium emisions to be held to under 1%. This law is now under attack
by lawyers arguing that the 1% should be measured at the edge of the property
rather than the edge of the cooling tower. Eliminating this law will save
power companies thousands of dollars in concrete costs for new nukes.

John Eaton
!hp-vcd!johne



Newsgroup: sci.electronics
document_id: 53604
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Ungrounded GFCIs; was: Re: A question about 120VAC outlet wiring.

In article <1qmisf$odp@sdl.Warren.MENTORG.COM> garyg@warren.mentorg.com writes:
>>
>>What you CAN do if you want three-prong outlets without additional wiring is 
>>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>>depending on where you are putting your new outlet(s), a GFCI may be *required*.
>
>You still need to supply a proper ground for a Ground Fault Circuit Interrupter!

Oddly enough, you don't, at least according to the wiring FAQ that
is regularly posted on misc.consumers.house.

A GFCI senses discrepancies between the live and neutral wire currents,
and cuts them both off if a discrepancy is found.  No ground connection
is needed for it to function.



-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53605
Subject: Re: Looking for a good Spice book
From: juhan@piko (Juhan Poldvere)

In <C5GIA7.7x9@acsu.buffalo.edu> NEIL B. GANDLER 
   (v064mb9k@ubvmsb.cc.buffalo.edu) wrote:

:>   I am an electrical engineering student and its a must that I get familiar
:> with spice. I have been using it and getting used to it but it would
:> be great to have a good reference manual that explains everything in an
:> organized and concise. I current have "A guide to circuit simulation &
:> Analysis using spice". I feel it has the information is just randomly placed
:> in the book and its not easy to look up small things when you just
:> need a good reference book. I would appreciate any info. Thanks

There is a postscript manual at ic.berkeley.edu in pub/spice3/um.3f.ps
directory (about 650kbytes, 126 pages).
--
Juhan Poeldvere, ES5QX                               | juhan@chem.ut.ee
Tartu University, Dept. of Chemistry                 | fax:   372 (34) 35440
2 Jakobi St., EE-2400, Tartu, Estonia, via Stockholm | voice: 372 (34) 35429

Newsgroup: sci.electronics
document_id: 53606
Subject: 2SC1096, 2SA634 specs?
From: juhan@piko (Juhan Poldvere)


Hi,
Could some kind soul post me the max power/voltage/current ratings of
2SC1096 and 2SA634 transistors, their conductance types and pinouts.
They are used in the sweep portion of a TV set.
Thanks in advance,
--
Juhan Poeldvere, ES5QX                               | juhan@chem.ut.ee
Tartu University, Dept. of Chemistry                 | fax:   372 (34) 35440
2 Jakobi St., EE-2400, Tartu, Estonia, via Stockholm | voice: 372 (34) 35429

Newsgroup: sci.electronics
document_id: 53607
From: aras@Ziggy.csl.ncsu.edu (Caglan M. Aras)
Subject: Polaroid Range finder interference-Help!

We have a setup with with 13 polaroid transducers and rangefinders. We
would like to fire these three at a time with about 5 ms between
firings. The three that are being fired do not fire in the same
direction. 

To further explain the situation, assume we are firing sonars A,B,C
5 ms apart each other. We should normally see an echo on A that
corresponds to the distance. However, sonar A detects the INIT line
of sonar B! The detection is actually through the transducer of sonar A;
we can see a very faint 50Khz signal on the transducer, exactly at the
time the init line of sonar B is activated. 

We feel that there is some ground coupling that is causing this interference.
We came to this conclusion since we are using a separate power supply
for sonars B and C. 

Has anyone else had any problems with these particular units and
this type of experience? Your suggestions for remedies will be greatly
appreciated.


-- 
Caglan M. Aras                 [] aras@eceris.ece.ncsu.edu
ECE Department                 [] ph: 919-515-5405
North Carolina State University[] fx: 919-515-5523
Raleigh, NC 27695              []

Newsgroup: sci.electronics
document_id: 53608
From: jra@law7.DaytonOH.NCR.COM (John Ackermann x 2966)
Subject: Single chip receiver for FSK?

My next project is to come up with an IF/detector module for fast -- 112
to 250 kB/sec -- packet radio use.  No fancy modulation scheme, just
wide FSK for use at 902 or 1296 MHz.

I'm a bit familiar with the Motorola 3362 chip, but I wonder if there
are newer designs that might work at higher input frequencies.

My goal is to come up with an inexpensive design for a receiver "back
end" with IF input on one end and an FSK demondulator on the other.  I'm
particularly interested in ways to use a higher IF than 10.7 -- do any
current chips work up to, say 150MHz with internal downconversion so a
normal IF filter can be used?

Any suggestions?

John

-- 
John R. Ackermann, Jr.         Law Department, NCR Corporation, Dayton, Ohio
(513) 445-2966		       John.Ackermann@daytonoh.ncr.com
Packet Radio: ag9v@n8acv.oh    tcp/ip: ag9v@ag9v.ampr [44.70.12.232]

Newsgroup: sci.electronics
document_id: 53609
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Re: History question

In article <kazel.15.734728882@uiuc.edu> kazel@uiuc.edu (Mitch Kazel) writes:
>Sorry if this isn't the correct news group . . . but . . .
>
>A colleague of mine is trying to find out when the first public use of 
>electronic voice amplification was  . . . i.e. a P-A system.
>
>Any reference would be appreciated.  Please reply via e-mail.

>Mitch Kazel (N9HDQ)
>INTERNET:  kazel@uiuc.edu

This is vague, so I am posting it in case anyone else knows more.

I recall reading of a phonograph which used mechanical amplification.
Compressed air was squirted out of a valve which was controlled by the
pickup.  The result was noisy and distinctly lo-fi, but much louder
than a conventional phonograph.  It tended to wear the disks out
pretty quickly though.

Paul.
-- 
Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
document_id: 53610
From: horne@cs.utexas.edu (Patrick J. Horne)
Subject: Thermal fuse supplier wanted

I have a thermal fuse from a Apple Laserwriter II power supply (Made
by Cannon) that I need to replace.  The fuse is not the standard
tubular thermal fuse like those found in hair driers etc, but is a 
rectangular plastic package, much like a transistor or diode.  It
is about 0.2"x0.2"x0.1", with both leads coming out of one of the
0.1"x0.1" sides.  I have been told that it was made by MITI, a asian
company, but I can find no information as to a supplier.  This fuse
is rated at 1A, 130C.  Does anyone have a source for this fuse?  I
only need 5 or so, which means that the manufacturer wouldn't even want
to talk to me, let alone, deal with me.

Please advise via E-mail.

Thanks,
Pat

-- 
---  I like boats and bicycles, they're healthier than Valium  ---
Pat Horne, Network Manager, Shop Supervisor, Hardware Guru 
CS Dept, University of Texas, Austin, Tx. 78712 USA 
voice (512)471-9517, fax (512)471-8885, UUCP:cs.utexas.edu!horne

Newsgroup: sci.electronics
document_id: 53611
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: $25 network

>>The same folks now have out LBL (Little Big Lan) for $75.  I think you
>>get it for $50 if you already own $25 Network.  LBL works with Arcnet,
>>parallel ports, and serial ports in any combination for up to 250 or so
>>nodes.

No flames please, but I picked up this discussion a bit late and I 
am really curious...

What exactly *is* the $25 network?
Something to hack together N serial cables?
Something with N serial drivers?

Thanks,
Pat

Newsgroup: sci.electronics
document_id: 53612
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: TDR plug-in

If anyone out there has an HP180 series scope or mainframe, I
have the TDR plug in (the 1810, I believe) for it and have no need
to keep it. Interested? E-mail me.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 53613
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Emulator pods

A surplus-dealing buddy of mine came up with two emulator pods:

	HP64220C (for HP 64100 development station). 8086 target
	processor. DIP head. Does not include board that plugs into
	the 64100.

	Applied Microsystems 80C186/188 pod, LCC head.

If you have an interest in either, let me know. They look to
be in excellent condition. He doesn't know what to do with them, which
may mean that they'll be cheap.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 53614
From: bill@xpresso.UUCP (Bill Vance)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

Dean Anneser (anneser@pwa-b.uucp) wrote:
: My 9 yr old son has signed up to do a science report on batteries.  I was
: wondering if anyone could provide me with some information as to how to
: construct a home-built battery.  In my grade school days, I remember seeing
: the 'ice cube tray' version, but I don't remember what to use as a good
: electrolyte or what the easily obtainable metals were.  

: Thank you in advance.

: Dean W. Anneser                  Pratt & Whitney Aircraft     
: Computer System Specialist       m.s. 161-05                       \__ -\  
: (203)565-9372 (desk) 5016 (fax)  400 Main St.               Ooo.. (_)-V/( )
: Uucp:     uunet!pwa-b!anneser    East Hartford, CT  06108    Live to Ride
: Internet: anneser@pwfire.pweh.utc.com
: "One test result is worth one thousand expert opinions" -- Wernher Von Braun 
: -- 
: Dean W. Anneser                  Pratt & Whitney Aircraft     
: Computer System Specialist       m.s. 161-05                       \__ -\  
: (203)565-9372 (desk) 5016 (fax)  400 Main St.               Ooo.. (_)-V/( )
: Uucp:     uunet!pwa-b!anneser    East Hartford, CT  06108    Live to Ride

--

The simplest one is easy.  Take a lemon or other citrus type fruit, and
stick a pair of metal strips into it for the contacts.  The two strips must
be of disimelar metals like copper and zinc.  Then connect a voltmeter to
the contacts and read the voltage.

bill@xpresso.UUCP                   (Bill Vance),             Bothell, WA
rwing!xpresso!bill

You listen when I xpresso, I listen When uuxpresso.......:-)

Newsgroup: sci.electronics
document_id: 53615
From: miller@hmsp04.wg3.waii.com (Griff Miller X7114)
Subject: Re: 68000

In article <1993Apr15.060043.15664@serval.net.wsu.edu> rwilley@eecs.wsu.edu (Ronald Willey - CS) writes:
>
>	The Supra accelerator that is mentioned in one of the pervious
>articles, is not 68000 or 68020 based.  It runs on a 68030 at 28Mhz and 
>the design they are using is very simple( if you were referring to the
>A500 exteranal model).

Hmm - I don't think you and I are thinking of the same thing. I was the
original poster, BTW. The accelerator that I'm talking about almost
certainly uses a 68HC000, according to the footnotes in the Supra ad. It
only costs $199 list, so I really doubt if it has a 28 MHz 68030 inside.

It's called the Supra 28, or Supra Turbo 28.
There's an external A500 model, and an internal A2000 model.

BTW, does anyone know if a 28Mhz 68HC010 exists?
--
Griff Miller >  Griff.Miller@waii.com  < use this for email.

      *** My opinions are mine, not Western's. ***

"Dear friend, do not imitate what is evil but what is good.
 Anyone who does what is good is from God. Anyone who does
 evil has not seen God." - 3 John 9

Newsgroup: sci.electronics
document_id: 53616
From: bps@ektools.kodak.com (Bruce P. Sidari)
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr15.212629.1834@cmkrnl.com> jeh@cmkrnl.com writes:
>In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
>> I'm considering modernizing some old wiring in my home, and
>> I need a little advice on outlet wiring.  Several outlets
>> are the old 'two prong' type, without the ground.  Naturally,
>> the wire feeding these outlets is 12/2, WITHOUT the ground
>> wire.  I noticed at the fusebox that some circuits have the
>> 12/2 with ground, and that on these circuits, the ground
>> wire was tied to the same bus as the neutral (white) wire.
>
>They are supposed to be connected together at the breaker panel... but nowhere,
>repeat NOwhere, else.  (Well, almost.  There are strange exceptions for things
>like sub-panels.)
>
>
>	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
>Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055
>

Not even in sub panels!  The only place the neutral should be connected to the
ground is in a SERVICE DISCONNECT!  In your house the "main" panel serves as
the service disconnect.  Sub panles in your garage or workshop for example must
maintain seperate neutral and ground busses because they are not  service
disconnect equipment.


Steve Woodard, KD2KQ - not a licensed electrician, but I can read the NEC book.
                       (my brother is though)  :)
 

Newsgroup: sci.electronics
document_id: 53617
Subject: Re: Exploding TV!
From: xhan@uceng.uc.edu (Xiaoping Han)

In article <1qk4hj$qos@vtserf.cc.vt.edu> prasad@vtaix.cc.vt.edu (Prasad Ramakrishna) writes:

>... Why would the picture tube explode or even smoke?

It's not the picture tube. More likely the flyback. Emerson? can't admire.
Han

>Prasad
>prasadr@vtvm1.cc.vt.edu
>



Newsgroup: sci.electronics
document_id: 53618
From: hooperw@spot.Colorado.EDU (Wayne Hooper)
Subject: Re: making copy of a Video tape

victor@inqmind.bison.mb.ca (Victor Laking) writes:

>You are experiencing what is called Macrovision.  It is the protection 
>that they use on the video tapes.  There are two ways around this that I 
>know of.  First of all, you can try using a different VCR to copy onto.
>It is the input of the VCR that reacts to the protection so sometimes 
>just switching the two VCRs around will take care of it.  Some models 
>just don't react to it.

Does this also affect the viewing of tapes ? I have had problems with
a couple of rented tapes; they were virtually unviewable. I fiddled 
with the tuning, tracking and vertical hold but it was no good.


Newsgroup: sci.electronics
document_id: 53619
From: lperez@decserv2.eecs.wsu.edu (Luis G. Perez)
Subject: Re: BEAM Robot Olympic Games next Week in Toronto.


Does anybody know if there is a mailing list or newsgroup for
Power Systems and related areas?

Thanks,

--
Luis G. Perez
lperez@eecs.wsu.edu


Newsgroup: sci.electronics
document_id: 53620
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Subject: Re: what to do with old 256k SIMMs?

 jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>	I was wondering if people had any good uses for old
>256k SIMMs...  So, if you have an inovative use (or want to buy
>some SIMMs  8-) ), I would be very interested in hearing
>about it.

About a month ago there was a photo posted on
alt.binaries.pictures.misc of a 17.5-inch Northern Pike which had been
caught on a lure made of 256K SIMMs.

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
Vote straight ticket Procrastination party Dec. 3rd!

Newsgroup: sci.electronics
document_id: 53621
From: heuvel@neptune.iex.com (Ted Van Den Heuvel)
Subject: Motorola MC14315 and MC143120 


Let me try sending this message again, I botched up the margins the
first time; *sorry* 'bout that :)

Does anyone out there know of any products using Motorola's Neuron(r)
chips MC143150 or MC143120. If so, what are they and are they utilizing
Standard Network Variable Types (SNVT)?
________________________________________________________________________

Ted Van Den Heuvel   heuvel@neptune.iex.com
KX5P
________________________________________________________________________

Newsgroup: sci.electronics
document_id: 53622
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Trace size for a 15 Amp supply

acollins@uclink.berkeley.edu (Andy Collins) writes:

>How thick do I need to make a PCB trace for 15 Amps of current? and
>Does anybody have any other thoughts on the process (what kind of PCB
>to use, materials, thickness of copper, any advice graciously accepted)?

In four replies, I've seen no hard numbers, so here goes:  For traces
on the outside (not inner layers), expect, in 1 oz copper, at 15 amps,
the following temperature rises versus width.  This is from Sams'
"Reference Data for Engineers," seventh edition, Pg 5-30, which claims
in turn to be from MIL-STD-275C...

    width   Temp rise
    inches  degrees C
    ------  ---------
     .125	100
     .15	 75
     .17	 60
     .20	 45
     .24	 30
     .33	 20

At 10 amps, the rise for the .125 width is only about 30 degrees.
Power goes as square of the current, plus the copper resistance goes
up as temperature goes up...  Certainly .20" (~5mm) traces should be 
ample for what you want to do.  And 2 ounce copper almost cuts the 
required width in half.  (I'd do 2 oz at about 0.08" width myself, 
I think...given that the _rated_ current is 10 amps and the 15 is
a transient or fault condition.)

(There's another question: will the voltage drop be low enough?
But you should be able to figure this one out with wire tables or
just the resistivity of copper.  Keep traces short and use separate
sensing traces where appropriate, as mentioned by another poster.)

Newsgroup: sci.electronics
document_id: 53623
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Looking for 900MHz Spread Spectrum Modules

butts@shocker.ee.twsu.edu (Ronald W. Butts, Jr.) writes:

>I am looking for suppliers of 900MHz spread spectrum radio modules. I need 
>to implement a two-way audio band link (essentially the guts of a cordless 
>900MHz phone is what I want.)

This isn't exactly audio, but take a look in "RF Design" magazine,
April 93, for the article "A Robust Signaling Technique for Part 15
RF Control Netowrk Applications."  Page 29.  Sources of parts are
mentioned; in the same issue is an article that features a chipset
for the Digital European Cordless Telecommunications standard.


Newsgroup: sci.electronics
document_id: 53624
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: A question about 120VAC outlet wiring..

crisp@ecsvax.uncecs.edu (Russ Crisp) writes:

>SO..  Here's my question.  It seems to me that I'd have the
>same electrical circuit if I hooked a jumper from the neutral
>over to the ground screw on new 'three prong' grounding outlets.
>What's wrong with my reasoning here?  

May I respectfully suggest you NOT do this??  The ground is
supposed to be a protective ground, and though what you suggest
looks good on paper, it's dangerous to rely on the same wire for
power and protection.  It'd never meet code, and if you now own
the property and later sell it, you may end up with liabilities
you don't want, and if you _don't_ now own it, well...

There's a "wiring" FAQ that I think addresses this.  I believe
an alternative is use of a GFCI, but I'm really not sure what
current code allows in this area.  The GFCI senses alternate
(unwanted) current paths, and doesn't rely on a specific
protective ground wire, at least not beyond the GFCI in the
protected circuit.  GFCI breakers are available (but expensive).


Newsgroup: sci.electronics
document_id: 53625
From: glenne@sr.hp.com (Glenn Elmore)
Subject: Re: Single chip receiver for FSK?

John Ackermann x 2966 (jra@law7.DaytonOH.NCR.COM) wrote:
: My next project is to come up with an IF/detector module for fast -- 112
: to 250 kB/sec -- packet radio use.  No fancy modulation scheme, just
: wide FSK for use at 902 or 1296 MHz.

: I'm a bit familiar with the Motorola 3362 chip, but I wonder if there
: are newer designs that might work at higher input frequencies.

: My goal is to come up with an inexpensive design for a receiver "back
: end" with IF input on one end and an FSK demondulator on the other.  I'm
: particularly interested in ways to use a higher IF than 10.7 -- do any
: current chips work up to, say 150MHz with internal downconversion so a
: normal IF filter can be used?

: Any suggestions?

: John

  What you describe is very close to what I built and described in the
10th ARRL Computer Network Conference proceedings.

  I built 10 watt FSK transceivers at 904 MHz.  They are essentially
double conversion transverters with digital mod and demod at 29 MHz.
The receiver uses the MC13055 which is the same FSK receiver chip I used
previouslyu in the 2 Mbps 10 GHz data link I first published in Ham
Radio and which is now also in the ARRL handbook.

  The MC3356, which includes a VHF converter section, could also be used
at these speeds.  There is a newer and perhaps slightly improved design
of this (the MC13056 if I remember rightly).

  While using this would have let me reduce the "external" IF count on
receive, it didn't really offer all that much help on transmit so I
didn't bother with it.

  The radios I built were first designed and built for 512 kbps in a 2
MHz channel but later reduced to half that.  These 256 kbps radios
actually have done quite well in across-the-bench tests at 384 kbps and
speed is pretty much a function of filter design.  Handling the data
stream is another matter entirely.

  Some of the existing radios are currently deployed on hilltops in a
"beacon" test mode.  While there is not yet end-end two-way data flow
due to lack of resources to debug software for the digital hardware (MIO
also shown in the CNC proceedings), data is perfect copy at n6gn.  Even
though the data clock is currently at about half speed, the a 2+ kbytes
of the test text (chapter 55 of Isaiah) takes only a little over 1/8 of
a second.

  I've been hoping that someone would get interested enough to step in
and get involved in writing code to make the whole thing usable (Borland
IDE environment with remote debugging possible as mentioned in the
proceedings) but to date a couple of us have been on our own and running
low on resources of time, money and energy.

  If anyone in the SF bay area wants to check it out there is also a CW
ID after the text on the mark side at 904.740 MHz from beacons on Sonoma
Mtn and Black Mtn (overlooking Si valley).  The antenna is horizontally
polarized.

  I guess in retrospect my suggestions are that this is a fairly costly
approach if the radios are intended for users rather than backbones and
you might want to carefully consider your "target".  If you can't
arrange your paths such that you have complete line-of-sight I think
you'll want to address the inter-symbol-interference caused by
multipath and probably link C/N budgets if paths are very far from LOS.
For more details, see the 10th CNC.  I'm currently working on a spread
spectrum, direct conversion design to address some of these problems.
I'd be glad to help as I can with any design problems.

73
Glenn Elmore n6gn

N6GN @ K3MC      
amateur IP:	glenn@SantaRosa.ampr.org
Internet:	glenne@sr.hp.com 



Newsgroup: sci.electronics
document_id: 53626
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: TDR plug-in

I have an HP 1815 TDR plug-in for an HP180 series scope or mainframe
that I'm never going to use (no scope any more). If you're interested
in it, please let me know. Price? Probably real cheap.

This notice may have appeared once before. I posted, and it never showed
up on our local server...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 53627
From: shanlps@ducvax.auburn.edu
Subject: TV RECEPTION:  HEELLLPPP!!!

Hello,

I just canceled my support of the Cable Regime and I would like to at
least pick up the 3 networks and NBC.  :)   I do not have tons of
money nor even a few pounds so what I am looking for is the best solution
for reception for under 100 dollars.  I have seen modules that you plug
into your wall outlet that "supposedly" make your entire house an
antenna.  I have to admit, even with my limited knowledge of wavelength
and aerial reception, this seems dubious in its claims for "excellent
reception" at best.  I'll try anything, though, if it WORKS.  I am in
a non-mountainous area, approximately 50 miles from the transmitting stations
which are pretty large (Montgomery Alabama pop. 200,000) and Colombus Goergia,
pop. 100,000+.  Any recommendations of products, brand-names, prices and 
company info (catalog ordering numbers, addresses etc.)?  Thank you in
advance.

Paul Sylvester Shanley   pshanley@humsci.auburn.edu   VOICE 205 887 7440


Newsgroup: sci.electronics
document_id: 53628
From: ddr@flux.isr.alaska.edu (Donald D Rice)
Subject: Heavy-duty antenna simulation software


I would be interested in hearing from anyone who knows of good software for
antenna simulation, particularly in source form suitable for Unix workstations
(though good PC software would also be of interest).
I'm aware of the numerous mininec mutations, and have been using MN for
some time now.  I'm primarily interested in HF, VHF, and low UHF (< 500 MHz)
designs, mostly wire antennas, but for thick wires and mesh surfaces as well
as for your basic thin wire assumption.
Is anything interesting happening with NEC itself?  I've seen a version
that was mutilated to run (sort of) under Microsoft Fortran, but I'm not
sure how many "new and improved" versions of the code might be out there
somewhere.
I'd also be interested in non-NEC derivatives.  The ones I've seen have
been aimed at microwave applications, but if there is something out there
useful at the lower frequencies, I'd like to know about it.
Thanks,
-- 
Don Rice                   E-mail: ddr@flux.isr.alaska.edu    (Internet)
Geophysical Institute              fnddr@alaska               (BITNET)
University of Alaska               flux::ddr                  (SPAN)
Fairbanks, AK 99775        Phone:  (907) 474-7569        Loran: 64.86N 212.16E

Newsgroup: sci.electronics
document_id: 53629
From: alung@megatest.com (Aaron Lung)
Subject: Re: IC Packages

In article <1993Apr16.142715.12613@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for some help in choosing a package
>for a high-speed silicon ADC (100Mhz) currently being 
>fabricated. This is a PhD research project and I have to test
>the chip at speed on a PCB. I expect to have roughly 100
>packaged circuits and will do DC, low-speed and high-speed
>testing using 3 different set-ups for the test chip.
> 	
>	I know for sure that a DIP will not work
>(the long lead lines have too high an inductance).
>Getting a custom-made package is too expensive, so
>I am trying to choose between a flatpak and a
>leadless chip carrier. The flatpack would be hard
>to test since it has to be soldered on to the test
>setup and I would spend loads of time soldering 
>as I kept changing the test chip. The leadless chip
>carrier sockets also have long lead lines and may
>not work at high speeds.
> 
>	Does anyone out there have experience/knowledge
>of this field ? I would greatly appreciate help! Any ideas/
>names of companies manufacturing holders/sockets/packages
>would help. 
> 
>P.S. The multi-layer fancy GaAs packages seem like a bit
>of overkill(?)
>	
> --- Seema Varma


You didn't mention whether or not cost is an issue.  Where
exactly are you running 100MHz??  THe digital side?  TTL?
ECL?  We run 200MHz and 100MHz all over our IC test equipment 
all day long in the ECL domain, and we use DIP's along
with PLCC's, 25mil and 20mil pitch 256pin QFP's to name
a few.  I don't see a problem in packaging as long
as you adhere to sound engineering practices.  

A good source of information is Motorola's MECL System Design
Handbook. The latest ed. is dated 2/88.  That is considered
to be one of the *bibles* in high-speed design.

The very fact that you need to build a test fixture means
you're most likely going to need a socket.  It in itself
has far more inductance per pin than the package you are
testing, not to mention any impedance discontinuities.  I
don't see the big concern over the packaging because it
probably isn't going to make that much difference

If you're trying to get TTL to run at 100MHz, have fun...
TTL was never designed to run in a 100MHz environment.
:-(

aaron

P.S. My opinions have nothing to do with my company...the
standard disclaimer applies.

Newsgroup: sci.electronics
document_id: 53630
From: alung@megatest.com (Aaron Lung)
Subject: Re: Adcom cheap products?

In article <1993Apr16.105738.20864@hippo.ru.ac.za> webb@itu1 (90-29265  Webber  AH) writes:
> ...stuff deleted...
>
>I was also sceptical about the amps being built in the far-east
>  or where-ever.  But if you look in the amp and see what components
>  they use and how it was designed, you can easily see why the
>  amplifiers sound so brilliant.

Good point...also, I wouldn't be surprised that the components
they use off-shore are of inferior quality.  As long as it was
properly designed and robust, premium components are used, it
shouldn't matter where it is assembled.

>I cannot see why people say the amplifier won't last - not with
>  those quality components inside.  Sure the amp runs very fairly
>  hot - but that's how you get an amp to sound incredibly good.

An amp that runs hot has no bearing on how it's gonna sound.
The amp you have probably is running Class-A the whole day.

Actually, I'd be wary of excessively hot amps, 'cauz even though
the components inside may be rated to run that way, excessive 
heat will dramatically shorten the life of *any* electronic component
regardless of quality.  In fact, an amp that does run hot to the touch is
because either the engineer or manufacturer of that amp wanted
to skimp on heatsinking or cooling to save costs!  Hmmmmm....

aaron

.

Newsgroup: sci.electronics
document_id: 53631
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <C5L5x0.KJ7@vcd.hp.com> johne@vcd.hp.com (John Eaton) writes:
>-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:

>During the nuclear fission reaction the uranium fuel can get hot enough
>to melt. When this happens the liquid uranium is pumped to the cooling
>tower where it is sprayed into the air. 

	Nonsense.  First, the uranium fuel is sealed in zirconium
alloy cylinders (which don't melt in any circumstances short of 
major failure of the power plant).  Second, the primary water
(that circulates inside the reactor core) is never pumped into the
cooling tower (it's the SECONDARY water cycle that goes 
through the cooling tower).  Third, liquid uranium would burst
into flame on contact with air.

>Contact with the cool outside air
>will condense the mist and it will fall back to the cooling tower floor.
>There it is collected by a cleaning crew using shop vacs and is then
>reformed into pellets for reactor use the next day.

	Cleaning crew working in a mist of uranium?  This is a
toxic heavy metal, even if it WEREN'T radioactive.  Shouldn't there
be some smileys here?  Or frowneys? 

	John Whitmore

Newsgroup: sci.electronics
document_id: 53632
From: rsf@cbnewsb.cb.att.com (roberto.s.freire)
Subject: Fluke Scopemeter

Has anybody out there used/tested these new Fluke Scopemeters?
How do they compare to a low-end Tectronix oscilloscope? Are
there any big drawbacks about these handheld scopes when
compared to the benchtop scopes of the same price range
($1000-$2000)?

Any info on the Fluke Scopemeters would be greatly appreciated.

Thanks,

Bob Freire
rsf@houxa.att.com



Newsgroup: sci.electronics
document_id: 53633
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: TV RECEPTION:  HEELLLPPP!!!

At 50 miles, a conventional set of TV antennas on a pole (one aimed
at each transmitter location) should work well.

"Rabbit ears" inside the house are probably not adequate.

Gadgets to plug into your house wiring are even worse.
At VHF, you don't want a _big_ antenna, you want a _resonant_
antenna.  

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53634
From: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
Subject: Optoisolator interfacing questions


I am interfacing some simple circuits that run on 9V to my
cpu board which runs at 5-6V.  The optoisolator is a 4N35.
On the led side, I put the signal I want through a 10k resistor
to the base of a 2N2222.  On the transistor side, I tie my
cpu input line to the collector which has a pull-up resistor
of 47k.

It functions OK, but seems VERY slow.  I can detect pulses
that occur at about 2kHz, but not much faster.  Isn't the
rise/fall time of this device, something like 5uS?  I should
be able to detect my target of 40kHz, but I can't get 16kHz.
This is done using wire-wrap and the wires going to the cpu
and to the test pin are about 8 inches long, but I'm not
doing anything high-speed.

In the Art of Electronics, it mentions tying the base of the
phototransistor to ground through a resistor to improve the
speed.  Is that what I need to do?  How do I calculate the
resistor value?


-- 

Paul Malenfant
pmalenfa @ kitkat.webo.dg.com (508-870-6460)

Newsgroup: sci.electronics
document_id: 53635
From: segal@rtsg.mot.com (Gary Segal)
Subject: Pinout needed for TIL311

I've recently picked up some TIL311 display chips, but I can't find
any information on them.  It seems they are no longer made by TI, and
I don't have an old enough data book.  :-(

It appears to have a dot-matrix led display capable of showing one hex
digit.  It is in a 14 pin DIP package, but pins 6, 9, and 11 are not
present.

If you have any information on this part (pinout, power requirments,
functions, ...) please send me e-mail.

Thank You,

-- 
Gary Segal                             Motorola Inc.            
segal@oscar.rtsg.mot.com               Cellular Infrastructure Division
	--- we are standing here only to gaze at the wind ---

Newsgroup: sci.electronics
document_id: 53636
From: martinkm@leland.Stanford.EDU (Kenneth michael Martin)
Subject: PADS model of a 68hc11.

Has anyone done a model of the 52 pin version of the 68hc11?  It doesn't
seem to be too big a job, but if someone else has already done it ...

many thanks
Ken Martin

Newsgroup: sci.electronics
document_id: 53637
From: jeh@cmkrnl.com
Subject: Re: Need help with car stereo....

In article <1qih53$9ho@usenet.INS.CWRU.Edu>, ae454@cleveland.Freenet.Edu
 (Paul Simundza) writes:
> My friend has a nice Alpine car stereo, and it only has 2 channels,
> but one of them does not work. It does not put out any current or voltage
> at all, is that channel therefore blown?  I then shut the radio off and
> ran continuity into the two speaker ouputs of the channel, and it charged
> and discharged so I know the wires just aint bad.... 

This probably only tells you that the DC blocking capacitor that's in series
between the one-chip, single-ended audio amp and the speaker terminal is there.

> any Ideas? 

Open it up and look for the power amp "ICs".  They'll be fairly obvious. 
Replace the one connected to the dead output. 

> also,
> how would I locate where the signal of the radio/tape unit is BEFORE it
> gets amplified, because then couldn't I hook up RCA outputs to that signal
> so then he could just use a little amplifier? 

Well, one thing you should do is poke around the terminals of the power amp
chips.  Use a probe with a 10M resistor (like a scope probe) connected to the
input of a small audio amp w/speaker.  If you find line-level input to both
chips, one of the chips is bad and can probably replaced pretty easily.  

If you want to pick off a near-line-level signal, suitable for feeding to an
outboard amp, the outer legs of the volume control pot will often be good
enough.  This is *before* the volume control (and usually before the tone and
balance controls too).  If you take off from the center and ground legs of
the volume pot, this will be after the volume control (but again, probably 
before the other controls).  

If the unit is a modern type with an electronic volume control chip, you should
probably forget the whole thing. 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
document_id: 53638
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Anyone know about DATA I/O device proggers ?

I keep finding these programmers in local junk shops. This may
mean that they are indeed junk - but i'd like to hear from anyone 
else that may have met up with them. The basic device is a
"Data I/O 29A universal programmer", and the usual pod is a 
"LogicPak 303A-Vo4" with a "303A-001" programming tester/
adapter. I'd really like to hear from anyone who knows whether
these monsters are worth bothering with. All i want to do is blast
PALCE22V10s. - Ideas, folks
Mike.

Newsgroup: sci.electronics
document_id: 53639
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: History question

Others said:
{early PA?}
# I recall reading of a phonograph which used mechanical amplification.
# Compressed air was squirted out of a valve which was controlled by the
# pickup.  The result was noisy and distinctly lo-fi, but much louder
# than a conventional phonograph.  It tended to wear the disks out
# pretty quickly though.

An now-deceased prof told us willing students about a project he had
worked on during WWII.

They needed a mega-power PA with very clear audio quality. The purpose
was to bellow at refugees from aircraft.

Their solution was a giant compressed-air source, and a horn with
parallel shutters worked by a small audio system. I think he said it
worked very well, thus the War Dept. cancelled the project ;_}.


--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
document_id: 53640
From: ankleand@mtl.mit.edu (Andrew Karanicolas)
Subject: Re: IC Packages

In article <1993Apr16.142715.12613@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Getting a custom-made package is too expensive, so
>I am trying to choose between a flatpak and a
>leadless chip carrier. The flatpack would be hard
>to test since it has to be soldered on to the test
>setup and I would spend loads of time soldering 
>as I kept changing the test chip. The leadless chip
>carrier sockets also have long lead lines and may
>not work at high speeds.
> 
>	Does anyone out there have experience/knowledge
>of this field ? I would greatly appreciate help! Any ideas/
>names of companies manufacturing holders/sockets/packages
>would help. 

Check with Kyocera America, Inc.
           24 Prime Park Way, Suite 150
           Natick, MA 01760

They are one of the largest manufacturers of IC packaging in the
world.

It sounds like you would be a good candidate for wafer probing or at
least IC probing to test performance.  HP, Cascade Microtech and
Tektronix should be able to help you here.  One note, testing at high
frequency accurately can be an *expensive* business.

-- 
Andrew Karanicolas
MIT Microsystems Technology Laboratory
ankleand@mtl.mit.edu

Newsgroup: sci.electronics
document_id: 53641
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: Exploding TV!

Others said:
# >... Why would the picture tube explode or even smoke?

Naw, it was the penguin on TOP of the set that exploded...
;-}

--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
document_id: 53642
From: lzahas@acs2.bu.edu (Lukas Zahas)
Subject: Re: How do DI boxes work?

In article <LANCER.93Apr15150228@oconnor.WPI.EDU> lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:
>
>I'm doing sound for a couple of bands around here and we need Direct
>Input boxes for the keyboards.  These are the little boxes that take a
>line level out of the keyboard and transform it into low-Z for the run
>to the mixer.  Sadly they cost like $50 (or more) each and I'm going
>to need like 5 or 10 of them!  I looked inside one (belonging to
>another band) and it looks like just a transformer.  Does anyone have
>any plans for building them?  
>
$50 each!!  Don't bother trying to make one yourself, just shop around a
little.  I've found DOD brand DI boxes for as cheap as $20 each.  You can 
get higher end ones for more, but for PA use for bands, I wouldn't bother.
Making one yourself might work, but getting a sturdy enough enclosure might
be hard (they're made of heavy guage metal, since they're always on the floor,
being kicked around a lot). For any additional questions on this topic, you 
might want to post to rec.audio.pro
						Lukas Zahas
						lzahas@bu.edu

Newsgroup: sci.electronics
document_id: 53643
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Radio Shack voice recognition chips

Hi there,

I have a friend who'd like to get a hold of a bunch of those simple voice
recognition chips that Radio Shack used to sell (and no longer does).  If
anybody knows of a source for these, please e-mail me.  I'll forward the
responses to him.

Thanks!

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 53644
From: Mark-Tarbell@suite.com
Subject: Switch-mode power supply

Is there a typical component or set of components
that are at fault when a switch mode power supply 
goes south?

The supply is for a disk drive. Any general hints
would be appreciated!

Thanks!
Mark-Tarbell@suite.com
at fault when a switch mode power supply 
goes south?

The supply is for a disk drive. Any general hints
would be appreciated!

Thanks!
Mark-Tarbell@s$$BVh(J

Newsgroup: sci.electronics
document_id: 53645
From: rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter)
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates

Where can you get info (brochures...) on Differential GPS Systems and where to 
buy them?

BobC



Newsgroup: sci.electronics
document_id: 53646
From: psgwe01@sdc.boeing.com (Gerald Edgar)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In making batteries you could use copper and zinc in an acid electrolyte.     
Copper=copper wire (pennies are now mostly zinc if I recall correctly)
zinc= zinc strip (Hardware stores arround here (Seattle) sell this to prevent
      moss buildup on the roof. An alternative would be to use a galvanized
      (zinc coated) nail
electrolyte= lemon juice -> Citric acid is the active ingrediant(sp).
 
Volta (late 18th century scientist) used a stack for his batteries-
copper disk, paper disk soaked in acid, zinc disk, copper disk, paper ....
they were advanced technology for the time. 
 
Gerald Edgar
gwe3409@atc.boeing.com
"The opinions expressed in this communication may not reflect those of my
employer"

Newsgroup: sci.electronics
document_id: 53647
From: st1my@rosie.uh.edu (Stich, Christian E.)
Subject: Motorola XC68882RC33 and RC50

I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
68030 + 68882 with capability to clock the FPU separately).  Previously
a MC68882RC25 was installed and everything was working perfectly.  Now the
systems displays a yellow screen (indicating a exception) when it check for
the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
fine, but with the XC68882 even at 25 MHz it does not work.  The designer
of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
might help, but that didn't change anything.  Does anybody have some
suggestions what I could do?  Does this look like a CPU-FPU communications
problem or is the particular chip dead (it is a pull, not new)?
Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
Are there any MC68882RC33?

Thanks
	Christian 


Newsgroup: sci.electronics
document_id: 53648
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Telephone On Hook/Off Hok

AllMichael CovingtonTelephone on hook/off hok

MC>From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
MC>Organization: AI Programs, University of Georgia, Athens
MC>Aye, there's the rub -- if you draw enough current to light an LED, th
MC>equipment at the phone company will think you've gone off hook.
MC>In the on-hook state you're not supposed to draw current.  

Ok lets have some calculation here: Going by Australian standards, which I 
presume might be similar to other countries ( If not, lets have some 
input) a phone uses 600ohm to loop a 48V line = 80mA. A standard LED 
drains 20mA. So what is the actual loop current required for an "off hook" 
indication, do you know?

Cheers 
Peter T.


Newsgroup: sci.electronics
document_id: 53649
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: What'S A Good Ic For Rs23

AllTall Cool OneWhat's a good IC for RS23

TC>From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
TC>Organization: University of Illinois at Urbana
TC>I'm looking for an IC that will convert RS232 voltage levels to TTL vo
TC>levels.  Something relatively inexpensive would be nice, too.  Anyone 
TC>a suggestion??  Thanks.

Try a Maxim "MAX232CPE" 8 pin dil, converts 5V to 12V for 232commms.
What a clever little gizmo!

Peter T.


Newsgroup: sci.electronics
document_id: 53650
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Swr Meter For Cb Radios

AllThe Devil ReincarnateSWR meter for CB radios

TD>From: ssave@ole.cdac.com (The Devil Reincarnate)
TD>Organization: CDAC, WA
TD>What
TD>is a good choice for a CB? 1/4 or 1/8 wave?
TD>  I read the installation instructions on a 1/4 wave antenna,
TD>and they suggested that I use an SWR to tune it at channel 12
TD>and channel 32 for a minimum reading.  Question is, why channel
TD>12 and 32?

The best antenna is one that will let out the most wave (probably not the 
best explanation, but the rest makes sense) A one wave will cancell itself 
out (BTW no such beastie) . The best is a 1/2 wave antenna, followed by 
1/4, then 1/8 etc.

As for SWRing in, what you actually do is trim the antenna to the correct 
length for the specific wavelength you will be transmitting on. Since the 
wavelength varies with the channel you use, then it's recommended to SWR 
in using the middle channel of those you are going to use.
Anyway in the beginning of CB's, all new antennas had to be SWR'ed in, 
nowdays manufactures trim the antennas almost spot on, so that there's not 
much point in SWRing. Then again you may be a fanatic and whish to do it 
anyway.

Cheers 
Peter T.


Newsgroup: sci.electronics
document_id: 53651
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: What'S Exactly In A Flour

AllMartin MccormickWhat's Exactly in a Flour

MM>From: martin@datacomm.ucc.okstate.edu (Martin McCormick)
MM>Organization: Oklahoma State University, Stillwater, OK
MM>	What sort of lamp is the little glass bulb found inside the 
starter?
MM>It sort of reminds me of a NE2 neon lamp.  Starters appear open when m
MM>with an Ohm meter so the little lamp is either a neon or has a capacit
MM>in series with it.
MM> 
MM>	I have seen these things all my life, but never read a really good
MM>description of what is happening inside that little can.

Do you know what a bi-metallic strip is?
Just in case: it is two strips of different metals bonded together, which 
when heated bend to one side (check out the blinker globe in your 
christmas tree lights).

So when you turn on the power, this causes the bulb to work like a neon, 
heating up and shorting out, thus providing a loop to power the heaters in 
the main tube. When the tube fires, insufficient current runs through the 
starter to keep the heat up and the bi-metalic strip straightens out 
(O/C).

BTW, I too thought that they were nothing more than a small neon, so one 
day when the neon in my sisters digital (flip the metal squares type) 
clock broke (flimsy leads), I replaced it with one from a starter. Well 
powering up made a bit of a mess of the clock!

Cheers
Peter T.   


Newsgroup: sci.electronics
document_id: 53652
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Dmm Advice Needed

AllMartin EmdeDMM Advice Needed

ME>From: mce5921@bcstec.ca.boeing.com (Martin Emde)
ME>Organization: Boeing
ME> 
ME>I an currely in the market for a DMM and recently saw an add
ME>for a Kelvin 94 ($199).  Does anyone own one of these or some
ME>other brand that they are extremely happy with.  How do the 
ME>small name brands compare with the Fluke and Beckman brands?
ME>I am willing to spend ~$200 for one.
ME> 
ME>Any help is greatly appreciated. (please email)
ME> 
ME>-Martin

If you are going to use one where it counts (eg:aviation, space scuttle, 
etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
for every other use you can buy a cheapie. I have a metex which is some 
made up name, as I have seen the same DMM with other brand names on it, I 
bought it about 4 yrs ago for Aus$125.00 (convert that to US and you see 
that it's definetly a cheapie.) So far it has proved to be accurate, taken 
moderate abuse, and has many features on it (CAP, FREQ,Transistor check, 
etc). I am very happy with it and would definetly not buy a fluke just for 
the name. Hope this helps.

Cheers 
Peter T.


Newsgroup: sci.electronics
document_id: 53653
From: R_Tim_Coslet@cup.portal.com
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
	swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
>I really don't know where to post this question so I figured that
>this board would be most appropriate.
>I was wondering about those massive concrete cylinders that
>are ever present at nuclear poer sites. They look like cylinders
>that have been pinched in the middle. Does anybody know what the
>actual purpose of those things are?. I hear that they're called
>'Cooling Towers' but what the heck do they cool?

Except for their size, the cooling towers on nuclear power plants
are vertually identical in construction and operation to cooling
towers designed and built in the 1890's (a hundred years ago) for
coal fired power plants used for lighting and early electric railways.

Basicly, the cylindrical tower supports a rapid air draft when
its air is heated by hot water and/or steam circulating thru a network
of pipes that fill about the lower 1/3 of the tower. To assist cooling
and the draft, water misters are added that spray cold water over the
hot pipes. The cold water evaporates, removing the heat faster than
just air flow from the draft would and the resulting water vapor is
rapidly carried away by the draft. This produces the clouds frequently
seen rising out of these towers.

That slight pinch (maybe 2/3 of the way up the tower) is there because
it produces a very significant increase in the strength and rate of
the air draft produced, compared to a straight cylinder shape.

The towers are used to recondense the steam in the sealed steam
system of the power plant so that it can be recirculated back to the
boiler and used again. The wider the temperature difference across
the turbines used in the power plant the more effecient they are and
by recondensing the steam in the cooling towers before sending it
back to the boilers you maintain a very wide temperature difference
(sometimes as high as 1000 degrees or more from first stage "hot"
turbine to final stage "cold" turbine).

                                        R. Tim Coslet

Usenet: R_Tim_Coslet@cup.portal.com
        technology, n.  domesticated natural phenomena

Newsgroup: sci.electronics
document_id: 53654
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Telephone On Hook/Off Hok

In article <734953838.AA00506@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:

>MC>Aye, there's the rub -- if you draw enough current to light an LED, th
>MC>equipment at the phone company will think you've gone off hook.
>MC>In the on-hook state you're not supposed to draw current.  
>
>Ok lets have some calculation here: Going by Australian standards, which I 
>presume might be similar to other countries ( If not, lets have some 
>input) a phone uses 600ohm to loop a 48V line = 80mA. A standard LED 
>drains 20mA. So what is the actual loop current required for an "off hook" 
>indication, do you know?

Up to 60 microamperes  =   on hook

Over something like 10 mA  = off hook

In between = defective line, and the phone company comes looking
              for leaky insulation.



-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53655
From: rmf@bpdsun1.uucp (Rob Finley)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


Intel also makes some neat memory and peripheral chips:

Old technology (early 1980's)  
8155  ram plus IO (slow ram as I recall)
8755  eprom plus IO (expensive and slow)


Intel does make Eproms with built in address latches.
I fear that you would need a very flexible and up-to-date eprom
programmer to write to them.

give them a call.  I am not able to locate their memory products book
yet.



Sigh...  Now, who borrowed it...

Robert



Newsgroup: sci.electronics
document_id: 53656
From: haynes@cats.ucsc.edu (Jim Haynes)
Subject: Re: History question


In article <1qnroe$d1n@usenet.INS.CWRU.Edu> wb8foz@skybridge.scl.cwru.edu (David Lesher) writes:
>An now-deceased prof told us willing students about a project he had
>worked on during WWII.
>
>They needed a mega-power PA with very clear audio quality. The purpose
>was to bellow at refugees from aircraft.
>
>Their solution was a giant compressed-air source, and a horn with
>parallel shutters worked by a small audio system. I think he said it
>worked very well, thus the War Dept. cancelled the project ;_}.

Gee, I got the idea from somewhere that devices like this were in common
use in WWII, so that commanders on board ships could bellow at the troops
landing on a beach, for example.

Which reminds me of an anecdote from the mid-60s.  At a communications
conference a Marine Corps communications officer said he didn't care
much for all the spread-spectrum multi-access expensive communication
systems that people were talking about at the time; what he wanted
was a kilowatt broadcast transmitter on the ship and a $4.95 Japanese
transistor radio stuck in the ear of every Marine hitting the beach.
-- 
haynes@cats.ucsc.edu
haynes@cats.bitnet

"Ya can talk all ya wanna, but it's dif'rent than it was!"
"No it aint!  But ya gotta know the territory!"
        Meredith Willson: "The Music Man"


Newsgroup: sci.electronics
document_id: 53657
From: gt0869a@prism.gatech.EDU (WATERS,CLYDE GORDON)
Subject: Re: History question

In article <2775@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:
>This is vague, so I am posting it in case anyone else knows more.
>
>I recall reading of a phonograph which used mechanical amplification.
>Compressed air was squirted out of a valve which was controlled by the
>pickup.  The result was noisy and distinctly lo-fi, but much louder


NASA and related agencies apparently used this same principles to create
the loudest reported reproduced sound. They used an "analog" electrically
controlled valve to control the flow of air across a horn throat. If I 
remember correctly it was called a "modulated air blast transducer". There
were reports of the thing being able to produce 106 dB @ 80 Hz @ 10 mile
distance, communicate directly with fighter pilots @ 5000 ft, etc.

Regards,
Gordon.

-- 
WATERS,CLYDE GORDON-BME '93-Georgia Institute of Technology Atlanta Ga. 
"Out of the mountain of despair, we can hew the stone of hope"- MLK Jr. 
uucp:	  ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0869a
Internet: gt0869a@prism.gatech.edu

Newsgroup: sci.electronics
document_id: 53658
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: subliminal message flashing on TV

> Hi.  I was doing research on subliminal suggestion for a psychology
> paper, and I read that one researcher flashed hidden messages on the
> TV screen at 1/200ths of a second.  Is that possible?  I thought the
> maximum rate the TV was even capable of displaying images was 1/30th
> of a second.  (or 1/60th of a second for an image composed of only odd
> or even scan lines)

You are correct; the fastest "complete" image that could be presented on
TV would be one field, which is 1/60 of a second (approximately).  Of course,
the phrase "TV screen" is often thrown around in reference to any CRT
display, so perhaps this researcher wasn't using normal TV rates.  Might
even be a vector ("strokewriter") display, in which case the lower limit
on image time is anyone's guess (and is probably phosphor-persistence limited).


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
document_id: 53659
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Scope questions

> 	If my life depended on it, I'd say that it's a scope that
> 	uses long-persistance phosphor to keep the successive
> 	taces on the screen for some unit of time - "store" them.
> 	Do I get to live?

We'll let you live, but just this once....

There's more to a real "storage" scope than just a long-persistence
phosphor.  Actually, the phosphor ISN'T usually anything special at all;
what makes a storage tube work is a screen placed just *behind* the phosphor,
which becomes charged as the electron beam intially "writes" the trace.
With the trace now written to the screen, a separate low-level "flood"
electron gun keeps the image lit by exciting those areas of phosphor
which are next to the "written" areas on the storage screen.  There are
some problems with this - the resolution is limited compared to a non-storage
tube, and the stored trace tends to "bloom" with time. 

Of course, this is pretty much obsolete technology, done in by the current
digital scopes which use raster-scan displays and keep everything in a
frame-buffer memory anyways.

> / Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
          ^^^^^^^^^^^^^^^^^^

Ah, yes - from the same people who brought you that amazing new reading
program that's sweeping Eastern Europe: "Hooked on Consonants!" :-)


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
document_id: 53660
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Dmm Advice Needed

In article <734953838.AA00510@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:
>
>If you are going to use one where it counts (eg:aviation, space scuttle, 
>etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
>for every other use you can buy a cheapie.

My Beckman died a few days ago, thanks do about a 4 or 5 foot drop onto a
lab table.  !@#!@$#!@$@#$  Probably not indicative of anything, but I've
already filled out the requisition for a Fluke 87. :-)

Oh yeah, and sometimes our measurements here do count.  Not often, but often
enough that I want at least _one_ good meter!

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 53661
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: What do Nuclear Site's Cooling Towers do?

Excerpts from netnews.sci.electronics: 16-Apr-93 Re: What do Nuclear
Site's .. by R_Tim_Coslet@cup.portal. 
> From: R_Tim_Coslet@cup.portal.com
> Subject: Re: What do Nuclear Site's Cooling Towers do?
> Date: Fri, 16 Apr 93 21:27:21 PDT
>  
> In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
>         swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
> >I really don't know where to post this question so I figured that
> >this board would be most appropriate.
> >I was wondering about those massive concrete cylinders that
> >are ever present at nuclear poer sites. They look like cylinders
> >that have been pinched in the middle. Does anybody know what the
> >actual purpose of those things are?. I hear that they're called
> >'Cooling Towers' but what the heck do they cool?
>  
> Except for their size, the cooling towers on nuclear power plants
> are vertually identical in construction and operation to cooling
> towers designed and built in the 1890's (a hundred years ago) for
> coal fired power plants used for lighting and early electric railways.
>  
> Basicly, the cylindrical tower supports a rapid air draft when
> its air is heated by hot water and/or steam circulating thru a network
> of pipes that fill about the lower 1/3 of the tower. To assist cooling
> and the draft, water misters are added that spray cold water over the
> hot pipes. The cold water evaporates, removing the heat faster than
> just air flow from the draft would and the resulting water vapor is
> rapidly carried away by the draft. This produces the clouds frequently
> seen rising out of these towers.
>  
> That slight pinch (maybe 2/3 of the way up the tower) is there because
> it produces a very significant increase in the strength and rate of
> the air draft produced, compared to a straight cylinder shape.
>  
> The towers are used to recondense the steam in the sealed steam
> system of the power plant so that it can be recirculated back to the
> boiler and used again. The wider the temperature difference across
> the turbines used in the power plant the more effecient they are and
> by recondensing the steam in the cooling towers before sending it
> back to the boilers you maintain a very wide temperature difference
> (sometimes as high as 1000 degrees or more from first stage "hot"
> turbine to final stage "cold" turbine).
>  
>                                         R. Tim Coslet
>  
> Usenet: R_Tim_Coslet@cup.portal.com
>         technology, n.  domesticated natural phenomena

Great Explaination, however you left off one detail, why do you always
see them at nuclear plants, but not always at fossil fuel plants.  At
nuclear plants it is prefered to run the water closed cycle, whereas
fossil fuel plants can in some cases get away with dumping the hot
water.  As I recall the water isn't as hot (thermodynamically) in many
fossil fuel plants, and of course there is less danger of radioactive
contamination.

Wayne Martin




Newsgroup: sci.electronics
document_id: 53662
From: mvanmeet@ua.d.umn.edu (Mike VanMeeteren)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <C5HHKo.1ry@vu-vlsi.ee.vill.edu> mobasser@vu-vlsi.ee.vill.edu (Bijan Mobasseri) writes:
>> There are two simple procedures for alterating any odometer.
>>
>>1. Mechanical driven odometer:
>>    Remove the speedo cable from the transmission.
>>    Attach a drill and run at max speed until the speedo turns over.
>>    Continue until the desired mileage is reached.
>====================================
>Admittedly an irrelavent question:for how long should the drill be running?
>
>Bijan

A verrrrrry long time, like on the order of days.  I had the pleasure of
doing that once (playing with the speedo cable) and with my B&D heavy duty at
full speed (600 rpm) all the speedo ever got up to was 30 MPH.  Now if you go
a high speed drill and ran it at say 4000 rpm, you could get 200 MPH out of
it.  (If you speedo doesn't burn out.)  Anyways, to roll a 100000 Mile
odometer would take 22 days or so.  Much easier just to take the speedo
apart.

Thought I'd share.  BTW, all this info was obtained legally  :-)


-- 
(~)~)~) o /)  _     Computer Lesson One: There is no "any" key, alternate keys
 / / / / /_) /_)                         are <shift>,<ctrl>,<caps lock>,<alt>
/ / (_(_/ (_/\_                          and sometimes <tab>.
mvanmeet@ub.d.umn.edu                                -consultant at lab

Newsgroup: sci.electronics
document_id: 53663
From: schmidt@auvax1.adelphi.edu
Subject: Grounding power wiring, was Re: a question about 120VAC outlet wiring

There has been quite a bit of discussion about house wiring and grounding
practices here.  A few points need to be clarified:

The Equipment GROUNDING conductor, Green, green with a yellow stripe, bare, or
the metal sheath or pipe of SOME wiring methods, is used as a safety ground, to
carry fault currents back to the circuit breaker panel, and to limit the
voltage on the metal case of utilization equipment or other metal objects.  It
should never (except for a few exceptions to be discussed later) carry the
normal operating current of a connected load.  Some equipment has filters in
the power supply which may cause some slight current flow through the grounding
conductor.  

Much communications or audio equipment is sensitive to noise or slight voltages
on the grounding conductor, and may require special wiring of the grounding
conductors to provide reliable operation  ("orange" outlets are often used for
this, with insulated grounding conductors wired back to the panel box, and in
many cases back to the service.  Anyone installing such a system should read
both the section on grounding in the National Electric Code and publications on
installing quiet isolated ground systems.  The code requires the insulated
grounding conductors (green wires) to run with the current carrying conductors
back to the panel box, and, if required, back all the way to the service
entrance , where it is bonded to the service ground (water pipe or rod)  Many
of these systems are installed illegally or unsafely, where they do not provide
a safe ground or a quiet ground or either. 

The GROUNDED conductor of a circuit, often called the NEUTRAL, which is
referred to in the code as the "identified" conductor and is supposed to be
white or natural grey.  This conductor is supposed to be connected to ground in
most electrical systems at a single point, generally at the service entrance
panel.  This connection is through the Main Bonding Jumper.  (In many household
service panels, the main bonding jumper is actually a bonding screw which
attaches the neutral busbar to the case of the panel)  

The Grounded conductor (neutral) is generally a current carrying conductor.  In
the case of a 120 volt circuit it is one of the two conductors completing the
circuit from the panel to the load device.  

Since the grounded conductor (neutral) is only connected to the grounding
conductor (bare or green) at the service entrance, if the load is any distance
from the service and draws any significant current, there will be a small but
measurable voltage between the grounded and grounding conductors at the load,
under normal operating conditions.  If you should (incorrectly) connect the
grounded (neutral) conductor to the grounding conductor at the load, some of
the neutral current will flow instead through the grounding conductor.  Since
there will now be current flowing through the grounding conductor, it will also
no longer be quite at ground potential at the load end.  If the load equipment
has a metal case, which is connected to the grounding conductor through the "U"
ground plug, the metal case is now also no longer quite at ground potential. 
The difference (under normal, non short-circuit conditions) may be only a few
tenths of a volt, but it could also be a volt or two.  This normally does not
present a shock hazard.  

HOWEVER, if you let the metal case of the grounded equipment come into contact
with an independently grounded object such as a water or gas pipe, a radiator,
a metal air conditioning duct or such, part of the neutral current will try to
flow through this aalternate ground path.  If the contact is not solid, you
will get a significant arc (a low voltage, but possibly moderate current arc)
Under the wrong conditions, this arcing could start a fire.  It is possible in
some cases that the sneak ground current   could also flow through a wire of
inadequate size, causing it to overheat.

With the incorrect non single-point grounding of the neutral, if there is a
short circuit from hot to neutral, the high short circuit current which may
flow will cause a much higher voltage on the grounding conductor, which
increases the possibility for shock or fire.  

Also if you incorrectly multiply connect the neutral and ground, the voltage on
the ground system is seen as noise bu computer or audio equipment, often
causing malfunction.  I have spent some hours tracking down such shorts in
technical facilities where they were inducing severe hum into equipment.

The Neutral is usually bonded to the ground at the distribution transformer as
well as at the service entrance of each dwelling.  This is done primarily for
lightning protection, so that induced lightning currents have a short path back
to ground, and also to assure that the currents drawn by shorts to grounded
objects like pipes draw enough current to trip circuit breakers or blow fuses
quickly.  The bad side of this is that not all the neutral current from the
dwelling goes through the neutral wire back to the transformer.  Some of it
flows through the grounding electrode (water pipe, etc.) this may cause
corrosion in the pipes and possibly in things like underground fuel oil tanks,
and it may also cause measurable AC magnetic fields due to the large loop
between the "hot" conductors in the service and the neutral current in the
water pipe and ground.  There are those who feel these fields may be unhealthy. 
(don't flame ME on this, I'm just telling you where the field comes from, not
it's health effect, as far as I'm concerned, the jury is still out on this.)

Note that the bonding jumper is only installed at the main panel, NOT at any
sub distribution panels.  This is one reason why it is illegal to run service
entrance cable with the sheath used as a neutral to a sub panel, you must have
a seperate insulated conductor for the neutral.  The sheath can be used in this
application only as the groundING conductor.  If the neutral is bonded to the
grounding conductor in the sub panel, say by forgetting to remove the bonding
screw, all the grounding conductors of the loads on that panel will be above
ground, with the possible problems listed above.

The code makes exceptions for ranges and dryers, as well as feeds from one
building to another.  In the cases of the range and dryer, the neutral may be
used as the equipment ground under certain conditions, instead of a seperate
wire.  Every time the code is revised, these exceptions come up for review. 
These exceptions were, in fact the first required safety grounds, in the days
before U ground outlets and such.  The appliance manufacturers don't want to
have to redesign their ranges and driers, and the contractors don't want to
have to run four wire cable (with four fairly heavy, expensive wires) in place
of three wire to the appliances.  No question it would be safer with seperate
neutrals to the stove, but the neutral current is low for most burner settings
(since most current is in the 220 volt "hots" except at some low settings, the
wires are large gauge, and there are few reported cases of injury or damage. 
So far, the exceptions have survived. In the case of feeds between buildings,
it's primarily for lightning protection.

People doing wiring should be aware what is and what isn't a legal grounding
conductor.  Obviously, the bare wire in "romex" 'with ground' is.  Anywhere
there is a green wire installed, such as in a portable cord, that is a good
grounding conductor.  The sheath of BX clamped in BX connectors in metal boxes
is a legal grounding conductor (in the US). (BX has an aluminum band run under
the steel sheath to lower the resistance of the sheath.  You can just cut this
aluminum band off at the ends, you don't have to bond it to anything, it does
its job by touching every turn of the BX sheath.) Conduit or EMT (thinwall
tubing) is generally a legal grounding conductor, but may require a bonding
locknut where it enters a box or panel, particularly for larger pipes.  

"Greenfield" (looks like big BX, but you pull your own wires in the empty
sheath after you run it) is NOT a legal grounding conductor, as it doesn't have
the aluminum band to bond it, and the spiral steel has too much resistance and
inductance.  You have to run a seperate green grounding conductor inside the
greenfield.

"Wiremold" is also not a legal grounding conductor, as the paint on the boxes
often prevents good contact, and the "feed" to the wiremold extension is often
from a box in the wall that may not be well connected to the first wiremold
box.  I have personally discovered cases where the entire run of wiremold and
the cases of everything plugged into all the outlets on the run were "hot" with
120 volts (Why do I get a shock every time I touch my computer and the radiator
here in the office?) because there was no ground wire in the wiremold and one
of the outlets had shorted to the edge of the wiremold box.  You must run a
ground wire back in the wiremold from the outlets at least to the first box in
the original wiring (conduit, BX, etc.) where you can "bond" the wire to the
box with a screw, bnding clip, or whatever.

On another issue, while you should ground the green wire/lug on GCFI outlets
when ever there is a place to ground them, it is legal in the NEC to use them
without a ground if no ground is available.  It is better to have the
protection of the Ground fault interrupter than no protection if you don't
install it.  The interrupter doesn't depend on the ground to trip.  It is
desirable to connect the ground if available, because if the ground is
connected, the interrupter will trip as soon as a faulty device is plugged in,
whereas without the ground, it will not trip until someone or something
provides a ground path.  For those questioning the legal use of ungrounded
GCFI's, read in the NEC, 210-7 (d) exception. (This is the 1990 code, my '93
code is in the city, but I know the rule hasn't changed.  It might be
renumbered though.) 

We have only touched the surface concerning grounding ;-} , there is much more
to this subject, but most of you have fallen asleep by now.  

John
-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218 
Adelphi University                 |       Evenings (516)877-6400 
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
document_id: 53664
From: zklf0b@wwnv28.hou.amoco.com (Fergason)
Subject: Re: what to do with old 256k SIMMs?

In article <1ql7ug$i50@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <120466@netnews.upenn.edu>, jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>|> 
>|> 	I was wondering if people had any good uses for old
>|> 256k SIMMs.  I have a bunch of them for the Apple Mac
>|> and I know lots of other people do to.  I have tried to
>|> sell them but have gotten NO interest.
>|> 
>|> 	So, if you have an inovative use (or want to buy
>|> some SIMMs  8-) ), I would be very interested in hearing
>|> about it.
>
>The most practical use I've seen for them is as key ring ornaments :-)
>
>JohnH

I used a bunch as weights, when building a model airplane.  Hung them
on the stringers, across the stringer, or whatever.  Worked pretty well.

Kelly


Newsgroup: sci.electronics
document_id: 53665
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Can I use a CD4052 analog multiplexer for digital signal

> As the subject says - Can I use a 4052 for digital signals?  I don't see
> why it couldn't handle digital signals, but I could be wrong.  Anyone have
> any advice?  Thanks.

Yes.

I use 74HC4066 and others commerically for this purpose so rest assured it 
works fine. In one case I route bit serial digital audio using these and it 
is difficult to see any signal degradation at all which surprised me given 
some pretty fast edges. HC4066 is spec'd at something like -3dB @ 200MHz into 
50 ohms. The more complex types are generally a little slower and more 
resistive.

Plain 4000 series are not so good at handling 5v logic.

Remember that the output load is seen by the input device.

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
document_id: 53666
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: Whats wrong with my cordlessphone?

I've also found that the electronic starters on these "instant-on" 
compact fluourescent lamp fixtures kick out interference that nukes
my cordless phone.  (I can hear it in my guitar amplifier, too...)
--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
document_id: 53667
From: cs000rdw@selway.umt.edu (Richard D Warner)
Subject: UART-CPU-ROM-RAM subsystem

	This is a followup post to something I've written previously.  Several
people responded with good information, but I don't think I communicated 
exactly what I am looking for.
	I'm working on a custom I/O device that will communicate with a host
via RS-232.  My custom circuitry will use an 80C186EB or EC CPU and require
about 64K of RAM (preferably FLASH RAM).  In looking around, I see that lots
of people have engineered UART-CPU-ROM-RAM subsystems that are ready to be
interfaced to your custom I/O devices.  It's been done so much, that it 
would be best if I can avoid reinventing a system.  It just needs to use
an 80C186 (or 188) CPU, and be able to load a program from the host then 
transfer control to that program.  Well, there's one other thing the ROM
needs to know how to do.  It should have routines to send and receive bytes
to/from the host, that utilize the hardware control lines (DTR,RTS,DTS,CTS).
Everything I've seen is in the $200.00 and up range.  That's too much for
this application.  I need something around $100.00.  The CPU has the UART
built-in, so you're only looking at a few chips.  Does anyone know a 
company that markets a good board in this range, or some public domain 
circuitry I can use?  Thanks in advance for the info.

Rich


Newsgroup: sci.electronics
document_id: 53668
From: ianmc@spartan.ac.BrockU.CA (Ian McPherson)
Subject: Re: chip / chipset for code 39 barcode?

LLBGB@utxdp.dp.utexas.edu wrote:
: Distribution: usa
: Reply-To: lihan@ccwf.cc.utexas.edu

: While I'm on the net bugging everyone, is there such a thing as a chip
: or chipset to decode Code 39 barcode?  I ask for a couple of reasons --
: mainly I want a reasonably compact encoding scheme to write information
: on magstripe cards and Code 39 appears to be about right.  (If the 'right'
: way to do it is something else, and it's reasonably easy, can someone let
: me know?)

: I might not get a chance to reply too quickly to this or my earlier post,
: but I'll get to them within a couple days, I think ..

: thanx everyone!  <BGB>  lihan@ccwf.cc.utexas.edu

Hewlett Packard has a series of barcode decoder ICs HBCR-1800, HBCR-2000,
and HBCR-2010 and they support 3of9  extended 3of9  interleaved 2of5  
and UPC codes. The 2000 and 2010 pieces add codabar and code 128.

These chips support HP's barcode wands and slot readers.

An 1800 + a HEDS-3050 wand run about $150 CDN .

Ian.


Newsgroup: sci.electronics
document_id: 53669
From: rbn@apple.com (Robert B. Neville)
Subject: Oscilliscopes for sale

Recently I posted two oscilliscopes for sale. One has sold, the other is
still available:
 Used, good condition:
 Hitachi V-422 40MHz Dual-Channel Portable Analog Oscilliscope
   o 1mV/div
   o DC offset
   o alternate magnification (10x magnified & non-magnified
     waveform)
   o VERT mode trigger
   o TV sync separation circuit
 List price      $910.00 (...and the price Fry's electronics just
                         quoted!) :-(
 Sells for       $699.99 (JDR MicroDevices current price)
                 $745.95 (Products International)
 Your price used $425.00 obo
...I haven't gotten an offer at the asking price, so 'obo' applies...

I also have a 'broken' version of the scope which sold:
 JDR 2000 20MHz Dual-Channel Portable Analog Oscilliscope
   o 5mV/div
   o Component Tester (resistors/caps/diodes/coils)
   o TV video sync filter
   o z-axis input (intensity modulation)

'Broken' means: The CRT produces a nice, bright trace, but the trace does
not correspond to the input signal. My guess is it's repairable but more
than a simple calibration problem...but I honestly have not tried to
calibrate the scope or otherwise fix it. It's 'as-is'.
I paid $60 for it in its current state (I bought it thinking I'd repair it,
using the 'good' scope for side-by-side comparison...since I've sold the
'good' scope, the 'bad' one doesn't do me much good) and I'd like to recoup
that amount. As above, I'll accept offers and take the best one.

I'd prefer a local (Bay Area, California) buyer, so (a) I don't have to
ship it and (b) she or he can examine the scope prior to purchase.

rbn@apple.com

Newsgroup: sci.electronics
document_id: 53670
From: nagle@netcom.com (John Nagle)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Wayne Alan Martin <wm1h+@andrew.cmu.edu> writes:
>Excerpts from netnews.sci.electronics: 16-Apr-93 Re: What do Nuclear
>Site's .. by R_Tim_Coslet@cup.portal. 
>> From: R_Tim_Coslet@cup.portal.com
>> Subject: Re: What do Nuclear Site's Cooling Towers do?
>> Date: Fri, 16 Apr 93 21:27:21 PDT
>>  
>> In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
>>         swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
>> >I really don't know where to post this question so I figured that
>> >this board would be most appropriate.
>> >I was wondering about those massive concrete cylinders that
>> >are ever present at nuclear poer sites. They look like cylinders
>> >that have been pinched in the middle. Does anybody know what the
>> >actual purpose of those things are?. I hear that they're called
>> >'Cooling Towers' but what the heck do they cool?
>Great Explaination, however you left off one detail, why do you always
>see them at nuclear plants, but not always at fossil fuel plants.  At
>nuclear plants it is prefered to run the water closed cycle, whereas
>fossil fuel plants can in some cases get away with dumping the hot
>water.  As I recall the water isn't as hot (thermodynamically) in many
>fossil fuel plants, and of course there is less danger of radioactive
>contamination.

       Actually, fossil fuel plants run hotter than the usual 
boiling-water reactor nuclear plants.  (There's a gripe in the industry
that nuclear power uses 1900 vintage steam technology).  So it's
more important in nuclear plants to get the cold end of the system
as cold as possible.  Hence big cooling towers.  

       Oil and gas fired steam plants also have condensers, but they
usually are sized to get the steam back into hot water, not most of the
way down to ambient.  Some plants do cool the condensers with water,
rather than air; as one Canadian official, asked about "thermal 
pollution" de-icing a river, said, "Up here, we view heat as a resource".  

       Everybody runs closed-cycle boilers.  The water used is 
purified of solids, which otherwise crud up the boiler plumbing when
the water boils.  Purifying water for boiler use is a bigger job than 
cooling it, so the boiler water is recycled.

					John Nagle

Newsgroup: sci.electronics
document_id: 53671
From: sundar@fiber-one.ai.mit.edu (Sundar Narasimhan)
Subject: how much would a Tektronix 2465A oscilloscope fetch

Hi: I'd like to know how much the foll. equipment will fetch in the used
equipment market (without manuals or other accessories):
	1. Tektronix 2465 scope
	2. Tektronix 2465A scope
	3. Tektronix 1240 logic analyser

Thanks much for your help.

Newsgroup: sci.electronics
document_id: 53672
From: rubin@cis.ohio-state.edu (Daniel J Rubin)
Subject: Re: what to do with old 256k SIMMs?

>>	I was wondering if people had any good uses for old
>>256k SIMMs.  I have a bunch of them for the Apple Mac
>>and I know lots of other people do to.  I have tried to
>>sell them but have gotten NO interest.

How hard would it be to somehow interface them to some of the popular 
Motorola microcontrollers.  I am a novice at microcontrollers, but I am
starting to get into them for some of my projects.  I have several 256k
SIMMs laying around from upgraded Macs and if I could use them as "free"
memory in one or two of my projects that would be great.  One project that
comes to mind is a Caller ID device that would require quite a bit of RAM
to store several hundered CID records etc...

                                                             - Dan
-- 
             Daniel Joseph Rubin     rubin@cis.ohio-state.edu 
     
                       GO BENGALS!      GO BUCKS!

Newsgroup: sci.electronics
document_id: 53673
From: eabyrnes@vela.acs.oakland.edu (Ed Byrnes)
Subject: Getting rid of screen wiggles?

My monitor display has a bad case of the wigglies. I have a good ground. I
live in an old house and I have replaced much of the wiring. I have two
EMI filters on the computer, the monitor plugs into the computer. When
fluorescent lights are on upstairs, the display jiggles, when motors run
in the house, the display jiggles, when incandescent lights are on in the
kitchen the display jiggles.  I could bring a separate line from the
breaker box, and use it only for the computer, would this do it? EMI
doesn't only travel the 110 volt line though. Should I shield the back of
the monitor? Ground a grid or plate? 
Your expertise is appreciated. Thanks very much!  Ed Byrnes
-- 
*---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---*
|   Ed Byrnes   FAX:  313-651-7392           eabyrnes@vela.acs.oakland.edu  |
|   Kensington Academy & Oakland University    Rochester, MI North America  |
*---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---* 

Newsgroup: sci.electronics
document_id: 53674
From: al@qiclab.scn.rain.com (Alan Peterman)
Subject: Fluke For Sale (was DMM Advice Needed)


I have a spare Fluke 8062A.  This is a true RMS digital meter with
4.5 digit display.  It's in "average" condition (been used) but 
works fine - which is what Fluke's are all about.   BTW - according
to the fellow who designed these meters, they can be converted to 8060A
function by clipping a jumper, and adding the 2 extra switches..
Like I said $115 seems fair - these sell for $300+ new.


-- 
Alan L. Peterman                                 (503)-684-1984 hm & work
                       al@qiclab.scn.rain.com
It's odd how as I get older, the days are longer, but the years are shorter!

Newsgroup: sci.electronics
document_id: 53675
From: mcole@spock (COLE)
Subject: 8051 Microcontroller

I would like to experiment with the INTEL 8051 family.  Does anyone out  
there know of any good FTP sites that might have compiliers, assemblers,  
etc.?

Newsgroup: sci.electronics
document_id: 53676
From: cjp1@aber.ac.uk (Christopher John Powell)
Subject: Fujitsu 8" HDD

I have a Fujitsu M2322K which has been removed (I believe) from a digital
X-Ray machine (takes X-Ray pictures without film).  The Fujitsu part number
is B03B-4745-B002A.

I have obtained some data on the device, it is 8-inch winchester-type
of 168 megabyte capacity (though I was told it was over 800 megabytes).
However, there is very little information on the interface standard used.
It appears to use two balanced-line connections, but what each connection
corresponds to I know not. One connection is a 30-way IDC, the other a
60-way IDC.

If anyone has any information on this device, I would be most grateful
if you could provide it.

Thanks.


Chris Powell.
-- 
+------------------------------------------------------------------------+
|  THE MAN FROM :  #####  #######  | JANET    : cjp1@uk.ac.aber          |
|                 #     #     _#   | Internet : cjp1@aber.ac.uk          |
|                 #     #  _#      | NYX      : cpowell@nyx.cs.du.edu    |

Newsgroup: sci.electronics
document_id: 53677
From: billq@ms.uky.edu (Billy Quinn)
Subject: Re: Radio Shack Battery of the Month Club

donrm@sr.hp.com (Don Montgomery) writes:


>Radio Shack has canceled their "Battery of the Month" Club.  Does 
>anyone know why?  

>They say they'll honor existing cards in customer hands, but no new
>cards will be issued.

I was told that this is an environmental based move.  I was also told that
there will be 'somthing' else to replace the battery club.  Like maybe
the 360K floppy club ;-).

We'll see ....
-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*

Newsgroup: sci.electronics
document_id: 53678
From: iisakkil@gamma.hut.fi (Mika Iisakkila)
Subject: Re: what to do with old 256k SIMMs?

rubin@cis.ohio-state.edu (Daniel J Rubin) writes:
>How hard would it be to somehow interface them to some of the popular 
>Motorola microcontrollers.

Not hard, you can do the refreshing and access cycles by software, but
this hogs most of the available CPU cycles on a low-end controller.
I've seen some application note from Philips that used one of their
8051 derivatives as a printer buffer, with up to 1MB of dynamic ram
that was accessed and refreshed with software bit-banging.

Another alternative would be to use one of those nice DRAM controller
chips that "create static RAM appearance" and all that, but they may
be too expensive to make it worthwhile.
--
Segmented Memory Helps Structure Software

Newsgroup: sci.electronics
document_id: 53679
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Public-domain circuits in commercial applications

In article <1993Apr13.164924.2606@wuecl.wustl.edu> dp@cec1.wustl.edu (David Prutchi) writes:
>Can circuits found in electronics magazines (with no patent disclaimer)
>be used legally as subcircuits of a commercial unit ?

There are two issues here:  copyright and patent.

The magazine article's contents are copyrighted, and may not be reproduced,
translated, etc., without the copyright holder's permission.  However, this
does not cover the *ideas* expressed, only the form of expression.  Copying
their circuit diagram or PC-board pattern is copyright infringement.  But
it's unlikely that they could stretch copyright far enough to claim that
the circuit design itself is copyrighted.  So long as you draw your own
diagrams and lay out your own boards, copyright shouldn't be an issue.

Patents are different.  The author does *not* have to give you any warning
that the design is covered by patent (although it would be sensible for
him to do so).  In fact, it's possible that *he* was infringing on someone
else's patent without realizing it.  Ignorance of the patented status is
not a defence against infringement, although it might reduce the damages
a court would award.

However... unless there was something seriously novel about the circuit,
almost certainly it is "obvious to one skilled in the art" and therefore
unpatentable.  Routine engineering is not patentable; patents (in theory)
cover only inventions, ideas that are genuinely new.

Caution:  I am not a lawyer.  Consulting a professional would be wise if
significant amounts of money are at stake.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53680
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Public-domain circuits in commercial applications

In article <C5GE03.LIF@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>... Patent law says you can build anything
>you want to, for your own personal noncommercial use...

I'm not up on the details of US patent law, but I think this is incorrect.
There is a "reasonable use" exemption for *copyright*.  There is none for
*patents*.  The exemptions from patent licensing are quite narrow; R&D work
is exempt but personal use is not.  That is, it's okay to experiment with
a patented idea, but not to put it to practical use (e.g. to improve your
stereo), even if it's only your own private practical use.

Of course, it is unlikely that discreet personal use will ever be detected
or that you will ever be sued over it.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53681
From: fculpepp@norfolk.vak12ed.edu (Fred W. Culpepper)
Subject: CAD Program for Electronics?

I am making a search for a CAD program that does a decent job
of making schematic drawings.  The program needs to be in
MS-DOS, Windows if possible.

What I want the CAD program to do is to draw diagrams by
dragging elements onto the screen, and in this the elements
needed are as diverse as vacuum tubes to ICs (case with pins).
It also needs to have provision for adding legends to the
components as well as their values.  In other words I want to
produce quality drawings.  Printout would be to either 24 pin
dot-matrix and/or Laser Printer.

If you know of such a CAD program that is of reasonable cost,
please respond.

Fred W. Culpepper
OLD DOMINION UNIVERSITY (Retired)
fculpepp@norfolk.vak12ed.edu
---

Newsgroup: sci.electronics
document_id: 53682
From: suwanto@iastate.edu (zapper)
Subject: Re: 2SC1096, 2SA634 specs?

>Could some kind soul post me the max power/voltage/current ratings of
>2SC1096 and 2SA634 transistors, their conductance types and pinouts.
>They are used in the sweep portion of a TV set.

2SC1096
  Maximum Ratings:
    VCBO = 40V
    VCEO = 30V
    IC   = 3A
    PC   = 10W (T=25C)

  ICBO max = 1uA
  VCB = 30V
  COB = 55pF

  at Q-point VCE=5, IC=1A --> hfe = 100

2SA634
  Maximum Ratings:
    VCBO = -40V
    VCEO = -30V
    IC   = -3A
    PC   = 10W (T=25C)

  ICBO max = -1uA
  VCB = -30V
  COB = 75pF

  at Q-point VCE = -5V, IC = -1A --> hfe = 100

That's all i can get from my data book, hope that helps.

suwanto@iastate.edu

    

Newsgroup: sci.electronics
document_id: 53683
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: what to do with old 256k SIMMs?

rubin@cis.ohio-state.edu (Daniel J Rubin) writes:

>How hard would it be to somehow interface them to some of the popular 
>Motorola microcontrollers.  I am a novice at microcontrollers, but I am
>starting to get into them for some of my projects.  I have several 256k
>SIMMs laying around from upgraded Macs and if I could use them as "free"
>memory in one or two of my projects that would be great.  One project that
>comes to mind is a Caller ID device that would require quite a bit of RAM
>to store several hundered CID records etc...

Assuming 68HC11...
In expanded muxed mode, you *could* do it. Much easier if you get a DRAM
controller IC. The MMI 673102 could be used to implement this, or you
could use a counter and a huge multiplexer to provide row/column/refresh
address multiplexing. The thing with DRAMs is that they require wierd
timing, address multiplexing, and refresh.

Actually, if you wanted to use a 68008 IC, you could look at AN897, which
has a neat controller built in. There is also the 683xx, I think one
of those has the DRAM controller built in. This one is for the 6664
DRAM, however, the 41256 has only one more address line, adding only
another component or so. The 256k SIMMs are basically 8 or 9 41256
DRAM chips (or their equivalent in fewer packages).

It *can* be done, just takes a bit of logic design. I'm actually
about to do it using a 65C02P3 chip... I've got 8 256k simms... that's
2 megabytes on my Apple //e... (used to be in my '386).


Newsgroup: sci.electronics
document_id: 53684
From: dannyb@panix.com (Daniel Burstein)
Subject: Re: What do Nuclear Site's Cooling Towers do?

<lots of pretty good stuff about how the huge towers near most nuclear
power plants are there to cool the used steam back into near ambient
temperature water deleted>

>>water.  As I recall the water isn't as hot (thermodynamically) in many
>>fossil fuel plants, and of course there is less danger of radioactive
>>contamination.

>       Actually, fossil fuel plants run hotter than the usual 
>boiling-water reactor nuclear plants.  (There's a gripe in the industry
>that nuclear power uses 1900 vintage steam technology).  So it's
>more important in nuclear plants to get the cold end of the system
>as cold as possible.  Hence big cooling towers.  

    as a point of info, some of the early nuclear power plants in this
country used the fission pile as a first stage to get the water hot, and
then had a second stage -fossil fuel- step to get the water (actually
steam) VERY HOT.

   I remember seeing this at Con Edison's Indian Point #1 power plant,
which is about 30 miles north of NYC, and built more or less 1958.


dannyb@panix.com

(all the usual disclaimers apply, whatever they may be)


Newsgroup: sci.electronics
document_id: 53685
From: mustafa@seas.smu.edu (Mustafa Kocaturk)
Subject: How starters work really

In article <734953838.AA00509@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:
>
>So when you turn on the power, this causes the bulb to work like a neon, 
>heating up and shorting out, thus providing a loop to power the heaters in 
>the main tube. When the tube fires, insufficient current runs through the 
>starter to keep the heat up and the bi-metalic strip straightens out 
>(O/C).

Imprecise. This description

 1. ignores the role of the ballast,
 2. misrepresents the heating effects in the starter.

The bimetalic strip cools down immediately after the contacts
short circuit, because the neon discharge stops, and much less
heat is generated from the I^2R loss in the metal as compared to
the neon discharge.

The starter contacts open before the tube fires.  Actually,
the tube fires as a result of the back-emf generated in the ballast
because of this immediate opening of the starter's contacts.

A capacitor is connected in parallel with the contacts to prevent
excessive arcing during the firing.  The neon reionizes but does not draw
sufficient current to prevent firing of the tube itself.
-- 
Mustafa Kocaturk   mustafa@seas.smu.edu  EE Dept., Room 305A, Caruth Bldg.
Home: 214-706-5954  Office: 214-768-1475  SMU Box 753190, Dallas, TX 75275

Newsgroup: sci.electronics
document_id: 53686
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: 74ACT???

In article <1qhrq9INNlri@crcnis1.unl.edu> mpaul@unl.edu (marxhausen paul) writes:
>OK, what's a quick rundown on all the 7400 series variations?  We're
>repairing something with a 74ACT00 on it and the question arises, "well,
>do  i really need the ACT part?"  Flipping through Digi-Key I see 
>ALS, AS, C, HC, AC, ACQ, ACT, HCT, ACHT, HCTLS...

Here's something I posted about this a few years ago.  It's not fully
up to date with all the new variations (some of which are just different
manufacturer's synonyms):

------
In practical terms, ignoring the technological details, this is my view
of the families (NB I am not a giant corporation, which influences my
views on things like availability and backward compatibility):

74	The original.  Speed good, power consumption fair.  Effectively
	obsolete now; use 74LS or later, except for a *very* few oddball
	functions like 7407 which are hard to find in newer families.

74H	Modification of 74 for higher speed, at the cost of higher
	power consumption.  Very obsolete; use 74F.

74L	Modification of 74 for lower power, at the cost of lower speed.
	Very obsolete; use CMOS.

74S	Later modification of 74 for even higher speed, at some cost in
	power consumption.  Effectively obsolete; use 74F.

74LS	Combination of 74L and 74S, for speed comparable to 74 with lower
	power consumption.  Best all-round TTL now, widest variety of
	devices.

74F	Fast as blazes, power not too bad.  The clear choice for high
	speed in TTL.  Availability and prices generally good.

74AS	Failed competitor to 74F, although a few 74AS parts do things
	that are hard to find in 74F and thus are still useful.

74ALS	Possible replacement for 74LS.  Generally souped up.  Still fairly
	new, availability and prices possibly a problem.

74C	Fairly old family, CMOS devices with TTL pinouts.  Competed with
	4000 series, not too successfully.  Obsolete; use 4000 or newer
	CMOS 74 families.

4000	(Thrown in as the major non-74 non-ECL logic family.)  The old CMOS
	family, still viable because of *very* wide range of devices, low
	power consumption, and wide range of supply voltages.  Not fast.
	Very forgiving and easy to work with (beware static electricity,
	but that comment applies to many other modern logic families too).
	There are neat devices in this family that exist in no other.  The
	clear choice when speed is not important.

74HC	A new attempt at 74-pinout CMOS.  Fast compared to old CMOS, power
	consumption often lower than TTL.  Possibly a good choice for
	general-purpose logic, assuming availability and affordability.
	CMOS logic levels, *not* TTL ones.  Beware very limited range of
	supply voltages compared to older CMOS, also major rise of power
	consumption at faster speeds.

74HCT	74HC with TTL logic levels.  Much the same comments as 74HC.  Read
	the fine print on things like power consumption -- TTL compatibility
	in CMOS involves some compromises.

10K	(Thrown in for speed freaks.)  The low end of ECL.  Various sources
	claim that it is *easier* to work with than super-fast TTL for
	serious high-speed work.  Less forgiving, though:  read and follow
	the rules or it won't work.  Availability to hobbyists limited,
	can be expensive.

100K	(For real speed freaks.)  Hot ECL.  Harder to handle than 10K, and
	inconvenient packages.  Much more useful datasheets, however.

As for compatibility between families:  the 74 families (except 74C and
74HC) are all more or less logic-level compatible, but how many 74X devices
you can drive from one 74Y output varies enormously with X and Y.  You just
have to read the specs and do the arithmetic.  74C and 74HC are compatible
with the others with a bit of hassle.  4000 compatibility can be a bit of
hassle or a lot of hassle depending on what supply voltage 4000 is using.
10K or 100K to anything else is considerable hassle.

Me?  I use 4000 and 74LS with a sprinkling of 74F.  74HC[T] and 10K are
interesting but I haven't used either significantly yet.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53687
From: jgd@dixie.com (John De Armond)
Subject: Re: What do Nuclear Site's Cooling Towers do?

swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) writes:

>I was wondering about those massive concrete cylinders that
>are ever present at nuclear poer sites. They look like cylinders
>that have been pinched in the middle. Does anybody know what the
>actual purpose of those things are?. I hear that they're called
>'Cooling Towers' but what the heck do they cool?
>I hope someone can help 


The actual hourglass is hollow and is designed to generate a draft,
exploiting the venturi effect.  Around the base of the hourglass is a
ring of water towers.  Warm river water, coming from the steam condenser
in the plant, is sprayed over louvres.  The draft being pulled through
the tower cools the water by both evaporation and convection.  The
sensible heat extracted from the cooling water is the driving force for
draft generation.

It should be noted that the hourglass-shaped cooling towers are used on
both fossile and nuclear plants.  It should also be noted that at 
locations where water is plentiful, the cooling towers are only used part
time, when the discharge temperature would exceed some release limit.
It was once thought that the warm discharge water was damaging to fish.
Fishermen know that is thoroughly incorrect.  Nontheless, stringent,
usually state, regulations remain in some instances.  Since it typically
takes 60,000 hp worth of pumping to move the volume of water needed 
to cool a 1000 MWe plant, the cost of using the towers is not insignificant.
-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine(TM) | Interested in high tech and computers? 
Marietta, Ga                         | Send ur snail-mail address to 
jgd@dixie.com                        | perform@dixie.com for a free sample mag
Lee Harvey Oswald: Where are ya when we need ya?

Newsgroup: sci.electronics
document_id: 53688
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: making copy of a Video tape

hooperw@spot.Colorado.EDU (Wayne Hooper) writes:

> victor@inqmind.bison.mb.ca (Victor Laking) writes:
> 
> >You are experiencing what is called Macrovision.  It is the protection 
> >that they use on the video tapes.  There are two ways around this that I 
> >know of.  First of all, you can try using a different VCR to copy onto.
> >It is the input of the VCR that reacts to the protection so sometimes 
> >just switching the two VCRs around will take care of it.  Some models 
> >just don't react to it.
> 
> Does this also affect the viewing of tapes ? I have had problems with
> a couple of rented tapes; they were virtually unviewable. I fiddled 
> with the tuning, tracking and vertical hold but it was no good.
> 


It sounds like your TV is one of the ones that also reacts to the video 
protection.  (Poor you!)

The Macroscrubber from Radio Electronics removes the protection so you 
souldn't have any more problems.  However, if you use the method of 
copying it from one VCR to another where the second VCR doesn't react to 
the protection, you will end up with a duplicate tape, including the 
protection.

One thought comes to mind about your problem...  When playing the tape 
for viewing, are you feeding the signal from the source VCR through an 
extra device before going to the TV?  If you feed it through a second VCR 
first, that is your problem.  As to other devices such as converters, I 
don't know if they would react or not.  Just to be safe, you might want 
to make sure that you have NOTHING between the VCR and TV.

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 53689
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: CRT driver transistors

Device........ LT1839   @ IC (mA)..... 50
V(BR)CEO (V).. 70       CCB (pF)...... 2.5
V(BR)CBO (V).. 120      VCE (V)....... 15
IC (mA) max... 300      Polarity...... NPN
hFE min....... 20       Package....... 79-04
hFE max....... 60       Material...... Metal
fT (GHz)...... 1        Price (100+)..

Device........ LT5839   @ IC (mA)..... 60
V(BR)CEO (V).. 65       CCB (pF)...... 1.5
V(BR)CBO (V).. 80       VCE (V)....... 10
IC (mA) max... 300      Polarity...... PNP
hFE min....... 15       Package....... 79-04
hFE max....... 60       Material...... Metal
fT (GHz)...... 1.5      Price (100+)..
@ VCE (V)..... 10

Anyone know of a source for these parts (other than straight from
Motorolla)?  I need 4 Lt1839's and 2 Lt5839 I've tried standard
and they said "We are out!"

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 13:50:28

... If there's one thing I can't stand, it's intolerance.
---
 * Blue Wave/QWK v2.12 *
                                                       

Newsgroup: sci.electronics
document_id: 53690
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: Analog switches/Balan

{Michael Fulbright} said
   "Analog switches/Balanced"
      to <All> on 04-15-93  01:08
 MF> I am trying to build a synchronous demodulator and I've hit a snag.
 MF> In my application I want to be able to change the gain of an
 MF> op amp amplifier from 1 to -1, controlable via a digital input.
 MF> The most obvious way I've come up with is to use analog switches
 MF> to adjust the gain of the op amp. The only analog switch I have
 MF> experience with it the 4066. Unfortunately I want to switch an
 MF> AC signal which goes from about -5V to 5V, and the 4066 is only
 MF> for positive signals.

    How about using a 4053 it has a seperate ground for the
    analog outputs.  It would get you 3 bits.

 MF> Another part which caught my eye was the Analog Devices AD630. This
 MF> is a balanced demodulator which appears to fill exactly the need I
 MF> have. The data sheet was somewhat skimpy on application notes. Could
 MF> someone comment on using this chip for the following application?

    Or how about a multiplying D/A convertor?  This is
    essentiallty what you are makeing.


                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 13:36:11

... Catch the Blue Wave!
---
 * Blue Wave/QWK v2.12 *
                          

Newsgroup: sci.electronics
document_id: 53691
From: v064mb9k@ubvmsd.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Need diode model for PSpice


	Im designing a circuit with just a silicon diode. I dont need
to modify any of the parameters. But the problem will not accept the following
statement
		
		.model diode D

        The pspice book I have is terrible. I would appreciate any help.


                                  Neil Gandler
 _____________________________________________________________________________
       Gandler Electronics
                            Home Automation & electronic design technology
 _____________________________________________________________________________

Newsgroup: sci.electronics
document_id: 53692
From: mlee@eng.sdsu.edu (Mike Lee)
Subject: Wire-Amperage table needed


Does anyone has a table about the size of the wire to the amount of current it can carry.  Probably in the 1-15amp range.  My friend is interested in converting a Mazda into an electric car.  Needed information for estimation.  Thanks in advance.  

p.s. any info on electric will be greatly appreaciated.  


Newsgroup: sci.electronics
document_id: 53693
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: making copy of a Video tape

In article <136390006@hpcuhe.cup.hp.com>, pi@hpcuhe.cup.hp.com (Paul Ilgenfritz) writes:
> 
> I think the Go Video dual cassette machines do a direct tape to tape copy
> which transfers Macrovision to the copy.  I you can find one of these, it
> would be worth a try.

Go-Video machines used in HQ2 mode will copy even the MacroVision.
Go-Video phone number (602)998-3400. 

Ask for sales department. Since the state of Arizona does not go on 
Daylight Savings time, we effectively are in Pacific time zone.

Allen Sullivan
Designing various stuff for GO-Video

Newsgroup: sci.electronics
document_id: 53694
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Others said:
# >       Actually, fossil fuel plants run hotter than the usual 
# >boiling-water reactor nuclear plants.  (There's a gripe in the industry
# >that nuclear power uses 1900 vintage steam technology).  So it's
# >more important in nuclear plants to get the cold end of the system
# >as cold as possible.  Hence big cooling towers.  

When the utility gave up on that Cinnci, OH plant (Zimmer?) and
announced they were going to convert it to a coal-fired scheme, the
turbines were already in place, and they were the low-temp type. So the
plan was: Install a SECOND set of high temp turbines, and feed the
low-temp ones with the output of the new ones.

Never saw anything more on this. Did they ever really build it?
--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
document_id: 53695
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: 74ACT???

Others said:
# 74S	Later modification of 74 for even higher speed, at some cost in
# 	power consumption.  Effectively obsolete; use 74F.
# 
# 74LS	Combination of 74L and 74S, for speed comparable to 74 with lower
# 	power consumption.  Best all-round TTL now, widest variety of
# 	devices.
# 
# 74F	Fast as blazes, power not too bad.  The clear choice for high
# 	speed in TTL.  Availability and prices generally good.

I hate to disagree w/ a fellow as smart as Henry, but...

A few years back, I worked on a project using lots of high-speed
stuff.  (My part was slow & parallel, whew.) The mild-mannered designer
working on the fast (serial) stuff cussed & swore at 74F all the time.
It was the Harry Reams of TTL. One ultra-tiny power line glitch, one
hickup, one eyeblink across the board, and bang - the F had
toggled/counted/whatevered.  At times he swore it would count even
without any 5 volt supply ;-} You can guess what the "F" stood for....

They would do anything to push S or work around it to avoid using F. I
don't think I'd consider using F to replace S unless the consequences
were *fully* understood.......
--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
document_id: 53696
From: ah499@cleveland.Freenet.Edu (John Daniels)
Subject: HELP!: Apple II Expansion Chassis by Mountain Computer


I recently bought an apparantly complete Expansion Chassis by Mountain
Computer Inc.  It consists of a box with 8 Apple ][+ compatible slots,
powersupply brick, interface card and ribbon cable to attach it to the computer
to be expanded.  There was also included a small card with empty sockets on top
and pins on the bottom that looks like it would plug into the ][+ motherboard
somewhere after pulling a chip.  There's an empty socket also on the interface
card and a short 16-pin DIP jumper like the ones used with ][+ language cards.
 
This technological marvel came with no docs and I haven't a clue as how to hook
this thing up.  If anyone has docs and/or users disk of any sort for this I
could really use copies of them or at least some help.
 
I need to know:
 
o How to orient the ribbon cable between the card and the chassis.
o How to attach the short cable from the motherboard to the card
  and if the small card is used.
o The purposes of the various jumper-pins on the card (it has more
  of those than my CMS SCSI card!)
 
 
thanks                                          John Daniels
                                                ah499@cleveland.freenet.edu
 

Newsgroup: sci.electronics
document_id: 53697
From: surfer@world.std.com (Internet Surfer)
Subject: 6551A and 6551 compatibility

Does any one know if the 6551 is timing/pin compatible with the 6551.. 
It seems the 6551 has in iheirent bug with cts/rts handshaking and i need
a suitable pin replacement to put in my serial card... possibly a buffered
version perhaps?


-- 
jolt@gnu.ai.mit.edu	      |    Its not impossible, just improbable
johnp@pro.angmar.uucp         |            (Zaphod Beeblbrox)
bl298@cleveland.freenet.edu   |   N1NIG@amsat.org (Being a Ham is so grand)

Newsgroup: sci.electronics
document_id: 53698
From: griffin@camelot.bradley.edu (Mark Valentine)
Subject: HELP: 20ma current loop to RS232 converter needed.


	Where can I buy or build a device that will convert 20 ma
current loop signals to RS232 voltages?  I know some old terminals
came with that option, but none of the ones I own have that.  Anyway,
I want to connect a computer to this old industrial computer to use
the computer with communications software as a console instead of
an old DecWriter.  Please e-mail me if you have any info that would
point me in the right direction.  



Newsgroup: sci.electronics
document_id: 53699
From: chris@alien.saar.de (Christian Reisel)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In <C5L5x0.KJ7@vcd.hp.com>, John Eaton writes:

   [...]
>During the nuclear fission reaction the uranium fuel can get hot enough
>to melt. When this happens the liquid uranium is pumped to the cooling
>tower where it is sprayed into the air. Contact with the cool outside air
>will condense the mist and it will fall back to the cooling tower floor.
>There it is collected by a cleaning crew using shop vacs and is then
>reformed into pellets for reactor use the next day.
>
>Cooling towers are a lot taller than they really need to be. Power companies
>are forced to make them that tall by some enviromental law that requires the
>raw uranium emisions to be held to under 1%. This law is now under attack
>by lawyers arguing that the 1% should be measured at the edge of the property
>rather than the edge of the cooling tower. Eliminating this law will save
>power companies thousands of dollars in concrete costs for new nukes.
>
>John Eaton
>!hp-vcd!johne
>

I think you posted your article 15 days too late :-)) April 1st is over.
I don't like nuclear powerplants but i think it's not fair to tell such
"storys" about them. OK ?
Let me try to explain what that tower is used to:
   -1st. Even the modernst nuclear powerplant is only a simple steam-engine.
         It has an hightech "boiler" but the rest is still verry verry 
         conventional. And if you've already visited any condensation-
         powerstation you'l have seen the cooling towers too.
         If you look at any good book about thermophysics you'll find
         a chapter about the "CARNOT-process" which describes how to
         get energy from a temperature difference ! And that is the reason
         for cooling towers too !!! You only can get energy if you've an
         temperature gradient. That means that you have steam on the one 
         side and need to cool down the steam 'till you get water
         again on the other side if you want to get aprox. 30% of the 
         energy you (or better the uranium) brought into the water to
         let it boil. If you only have hot steam on the one and "cold"
         steam on the other side you'll loose much more of the energy.
         And so they cool down the steam to get at least the 30% of
         energy that carnot will give them.
         The cooling towers are for cooling the steam !
         The vapor you'll see is NOT the steam of the main core circulation,
         because that steam is radioactive ! The circulation is divided in
         AT LEAST 2 circuits connected about heat exchangers to prevent
         radioactive pollution of the environment !
         
   -2nd. OK, the main core IS hot, but even in the modernst HighTemperature-
         Reactors (HTR) they only run at ~800 deg celsius. This is still
         verry far away from uraniums melting point which is somewhere
         around 2000 deg. celsius ! But you'll have lot's of problems with
         the boiler's steel. That's because at this temperature the
         metal is attacked by steam and will corrode verry fast.
         This is only for BWR's. The new He cooled reactors have temperatures
         up to 1200 deg. celsius. But this is only experimental. 

   -3rd. I personaly think that nuclear waste should be as low as ever
         possible because the dose you get will accumulate about the
         years. Today 1 mRem and next year 0.5 mRem won't be 0.75 mRem
         at all. It accumulates and even in 80 years you'll still have
         1.5 mRem. And i'm not interested in glowing in the night and
         getting children with 2 heads. This is my point of view.
         

Only my 0.02$ !

Christian Reisel 

student of electronic sciences

-- 
Christian Reisel, Goldammerweg 2, W-6601 Buebingen, Germany
Voice        +49 6805 22179 Fax & Email  +49 6805 22179

PGP PubKey:
--------------------------------------------------------------
begin 777 pcr.pub
MF5L`P`"S*Q%296ES96PL($-H<FES=&EA;OX!P7R5'F0QY1Q_.=+SY(;DZ0L:6
MMO(]]0`=K?/VH[U-"6MX]7G\-MF]/;&`H5KL/%,M\$:89^5FI6;W:$T$;9M!Q
$+04`$0`=@
``
end

Newsgroup: sci.electronics
document_id: 53700
From: adykes@jpradley.jpr.com (Al Dykes)
Subject: help: How to reduce the RPMs of a Boxer fan ?


I need to reduce the speed of a Boxer fan by about 30-50%. I recall
reading somewhere that the right capacitor in series will do it.

If this isn't a case of brain fade, can someone suggest the cap value ?

The specifics; It's a real Boxer Fan (tm). The label says 115 V, .2 amps.

Al Dykes
--------
adykes@jpr.com






Newsgroup: sci.electronics
document_id: 53701
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: **] A/D board quiry:

 
        On an A/D board I've got, I'm using the A/D lines.  It measures 
the voltages properly, ie: with a 7v power supply it reg's 7v and with 
5v, it reg's 5v.  Problem is when I've got the input voltage, and I wish 
to lower it via a resistor.  The sensitivity of the board is so great 
that I can triger it with holding the 5/7v wire in one hand, and touch 
the probe and it will register the full input voltage.  A 1m resistor 
only lowers voltage by .1v so this is not too feesable. 
 
                What could the problems be and what else could I use
to lower the input voltage?  (btw I've got it grounded correctly)
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
document_id: 53702
From: alee@ecs.umass.edu
Subject: Need to find out number to a phone line


Greetings!
      
        Situation:  I have a phone jack mounted on a wall.  I don't
                    know the number of the line.  And I don't want
                    to call up the operator to place a trace on it.

        Question:   Is there a certain device out there that I can
                    use to find out the number to the line?
        Thanks for any response.
                                                    Al

  

Newsgroup: sci.electronics
document_id: 53703
From: frankh@scraps.uucp (Frank Holden KA3UWW)
Subject: Re: What's a good IC for RS232 -> TTL signals??

In <C57zsC.9FL@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:



>I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
>levels.  Something relatively inexpensive would be nice, too.  Anyone have
>a suggestion??  Thanks.


Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
you want.  They are selling it for about $3.50...

Hope this helps...
Frank

-- 

**************************************************************************
* Customer asked "What's that thing?".                                   *
* I answered chuckling "Well, it's a highly technical, sensitive         *
* instrument I use in computer repair! Being a layman, you probably      *
* cann't grasp exactly what it does. I call it a B.F.H.....              *
* Frank W. Holden - KA3UWW - "The Radio Doctor"                          *
* - - - - - - - - - - - - - - - - - | - - - - - - - - - - - - - - - - -  *
* SnailMail:                        | Inter-Net:                         *
* 685 Addison St.                   | frankh@scraps.pittsburgh.sgi.com   *
* Washington, Pa. 15301-5601        | Packet:ka3uww@n3idi.#wpa.pa.usa.na *
**************************************************************************
DISCLAIMER:<disclaimer.h> - I confess, you did it!!!
-- 

**************************************************************************
* Customer asked "What's that thing?".                                   *
* I answered chuckling "Well, it's a highly technical, sensitive         *

Newsgroup: sci.electronics
document_id: 53704
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: Need to find out number to a phone line

alee@ecs.umass.edu writes:


>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.

>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al

There usually is a way, however, often, telephone companies like to
keep all of their internal numbers private. Depends on your exchange.
Any modern electronic switching equipment usually have voice synth
lines that echo the number you called from. The line service guys use this
to make sure they connect up the right pairs of lines.



Newsgroup: sci.electronics
document_id: 53705
From: bryan@philips.oz.au (Bryan Ryan)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)

spp@zabriskie.berkeley.edu (Steve Pope) writes:

>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>	Hello again,
>> I asked this a year ago, but i am still looking.
>> I am getting sick of having to use a HC373 

>Jeff, just use the damned 373.   Sure, there are oddball
>latched memory chips, but do you really want to use them?

>Sorry if I'm pedantic but: design your circuit using
>reasonably available parts, and move on to more important
>problems.

We're looking at a series of chips by WSI, the PSD3xx series. They have
_mega_ address decoding logic on them, various ROM sizes (upto 1Mbit),
various RAM sizes (upto 16 K), and 19 I/O ports which can be chip select
lines, I/O or the buffered address lines.

Cute chip, 44 pin PLCC package.

Second sourcing may be a problem though :-(


Bryan Ryan, VK3TKX
Melbourne, Australia
bryan@philips.oz.au


Newsgroup: sci.electronics
document_id: 53706
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: what to do with old 2

{Jason Haines} said
   "what to do with old 256k"
      to <All> on 04-15-93  04:38

 JH> I was wondering if people had any good uses for old
 JH> 256k SIMMs.  I have a bunch of them for the Apple Mac
 JH> and I know lots of other people do to.  I have tried to
 JH> sell them but have gotten NO interest.

    How about collecting them all together (IE everyones) and
    selling them as a lot?  The other thing is to give to a
    recycler.

 JH> So, if you have an inovative use (or want to buy
 JH> some SIMMs  8-) ), I would be very interested in hearing
 JH> about it.

    If they are free and you can send them real cheap!  I would
    be intrested in them.  hehehe  Are these 2 chip or 8 chip
    devices what speed?

 JH> I have seen RAM disc storage devices but they have been
 JH> very pricey (plus I am still a little worried about having data
 JH> stored on RAM).

    Why?  Do you use a RAM disk? :)

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 19:58:29

... Badgers... we don't need no steenking Badgers!
___ Blue Wave/QWK v2.12
                                                        

Newsgroup: sci.electronics
document_id: 53707
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: what to do with old 2

{Kris Gleason} said
   "Re: what to do with old 2"
      to <All> on 04-15-93  11:02
 KG> Yeah... keychains.  I have seen 64K simms with a silver 
 KG> keyring attached, big seller at the computer store.  I'm
 KG> sure you could find a bunch of geeks^H^H^H^H^H^H computer
 KG> science majors around that would buy them for $10.  Maybe
 KG> $15, if you're lucky.

    Untrue they would check JDR first and say 5.  That's how much
    they are worth AT MOST.  My guess is they are worth 1 buck
    a peice.

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Sat  04-17-1993  at 20:26:37

... This tagline is a duplicate.   This tagline is a duplicate.
___ Blue Wave/QWK v2.12
                                                                     

Newsgroup: sci.electronics
document_id: 53708
From: thompson@cactus.org (Charles Thompson)
Subject: How does "Differential Mode" GPS work???



I understand that the new GPS boxes now have an option
known as "differential ready".  Apparently land-based
beacons tranmit GPS correction information to your GPS 
receiver (with differential option installed).

How does this system work?  What frequency is used for
the land-based beacons?

Thanks in advance,

Charlie Thompson
.


Newsgroup: sci.electronics
document_id: 53709
From: ski@wpi.WPI.EDU (Joseph Mich Krzeszewski)
Subject: Re: Need to find out number to a phone line

In Texas (Well, Corpus Christi anyway) if you pick up the phone and dial
890 the phone company will read back the number to you.
Try it. It might work.


Newsgroup: sci.electronics
document_id: 53710
From: rcook@gfx.engga.uwo.ca (Richard Cook)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al
>
>  


How about calling someone with the Caller ID service and have them call you back
with the number?

-- 

Richard Cook    (519) 641-1985     E-mail:  rcook@gfx.engga.uwo.ca
Elect. Eng. FAX	(519) 661-3488

Newsgroup: sci.electronics
document_id: 53711
From: markz@ssc.com (Mark Zenier)
Subject: Re: Can I use a CD4052 analog multiplexer for digital signals?

Tall Cool One (rky57514@uxa.cso.uiuc.edu) wrote:
: As the subject says - Can I use a 4052 for digital signals?  I don't see
: why it couldn't handle digital signals, but I could be wrong.  Anyone have
: any advice?  Thanks.

The switches have a non-negligable on resistance (up to 1k ohm when
powered by 5 volts) and a maximum current and a Maximum Static
Voltage Across Switch.  Not a good bet for TTL.  Should work for
CMOS, but slow things down a bit.  There are 74HC versions that
have better specs. but lower max voltage.

Mark Zenier  markz@ssc.wa.com  markz@ssc.com  


Newsgroup: sci.electronics
document_id: 53712
From: markz@ssc.com (Mark Zenier)
Subject: Re: Illusion

Chris Best (cab@col.hp.com) wrote:
: > This is not a new idea.  At least 10 years ago I got this little gadget with
: > a keyboard on the back and 8 LED's in a vertical row on the front.  It has a
: > long handle and when you wave it in the air it "writes" the message you typed
: > on the keyboard in the air. 
: 
: This is not news.  In fact it's where I got the idea from, since it was
: such a neat item.  Mattell made it, I believe, modeled after a "space 
: saber" or "light sword" or something likewise theme-y.  My addition was 
: using a motor for continuous display, and polar effects in addition to 
: character graphics.  I should have protected it when I had the chance.  
: No one to kick but myself...
: 
: Ten years ago is about right, since I built mine in '84 or '85.

It's even older than that.  I remember seeing a description of
a garage operation selling them at some of the early Computer Faires 
in San Francisco about 5 years before that.


Mark Zenier  markz@ssc.wa.com  markz@ssc.com  


Newsgroup: sci.electronics
document_id: 53713
From: dnewman@lynx.dac.northeastern.edu (David F. Newman)
Subject: voltage regulator spec needed !!!!!

Hi there,
I have a mac 512 with a burned out part which looks like a voltage
regulator.  The part number is BU 406 and I believe the vender is
SGS thomas judging by teh SGS logo printed on the package.  If anyone
has teh spec for this part I would greatly appreciate an email with
the import info so I can find a replacement.  Thanx in advance.

-Dave
dnewman@lynx.northeastern.edu

BTW I don't need people telling me to throw the computer away.  If
  I had the money the thing would be in the trash in a second, but
  it does make a good terminal if nothing else.

Newsgroup: sci.electronics
document_id: 53714
From: berryh@huey.udel.edu (John Berryhill, Ph.D.)
Subject: Re: What do Nuclear Site's Cooling Towers do?

The object of a cooling tower is to distribute dissolved salts in 
cooling water over large areas of farmland and to therefore decrease
farm subsidies for non-producers by rendering their land infertile.

A side effect of this deficit-reduction program is that they provide
a low-T reservoir for a variety of industrial processes.

Now you know. 

-- 

                                              John Berryhill


Newsgroup: sci.electronics
document_id: 53715
From: xandor@unixg.ubc.ca (John Gilbert )
Subject: Re: Exploding TV!

 Just as a not of possible interest on this subject ..
It is my understanding that exploding televisions were a major cause of
domestic accidents in the Soviet Union in past years!
  

Newsgroup: sci.electronics
document_id: 53716
From: jeh@cmkrnl.com
Subject: Re: A question about 120VAC outlet wiring.

In article <1qmisf$odp@sdl.Warren.MENTORG.COM>, garyg@warren.mentorg.com (Gary Gendel) writes:
> In article 1834@cmkrnl.com, jeh@cmkrnl.com writes:
>>What you CAN do if you want three-prong outlets without additional wiring is 
>>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>>depending on where you are putting your new outlet(s), a GFCI may be *required*.
> 
> You still need to supply a proper ground for a Ground Fault Circuit Interrupter!

Not according to the NEC nor the CEC, as explained in the electrical wiring 
FAQ, which I posted here separately.  Note the material under the headings

> Subject: How do I convert two prong receptacles to three prong?

and

> Subject: Are you sure about GFCIs and ungrounded outlets?
> 	Should the test button work?

Of course, as they said -- "Local codes may vary". 

> So rewiring is still a part of this job, however, the ground may be connected to
> a local earth ground, rather than back at the breaker box.

I'm not sure about this.  If the ground connections on the outlets are
connected to anything, they should be connected to a wire that runs back to the
main panel, where it is bonded to the neutral connector and to the house ground
rod.  A connection to a local earth ground would not necessarily meet one of
the goals of the ground wire, which is that if a short develops from hot
to the ground wire, enough current would flow to trip the breaker.  

Hmmm.  How are those orange "isolated ground" outlets (often used in
computer rooms) wired?  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
document_id: 53717
From: sgberg@charon.bloomington.in.us (Stefan G. Berg)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu> st1my@rosie.uh.edu (Stich, Christian E.) writes:
> I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
> 68030 + 68882 with capability to clock the FPU separately).  Previously
> a MC68882RC25 was installed and everything was working perfectly.  Now the
> systems displays a yellow screen (indicating a exception) when it check for
> the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
> fine, but with the XC68882 even at 25 MHz it does not work.  The designer
> of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
> might help, but that didn't change anything.  Does anybody have some
> suggestions what I could do?  Does this look like a CPU-FPU communications
> problem or is the particular chip dead (it is a pull, not new)?
> Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
> that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
> Are there any MC68882RC33?

I, too, have a XC68882RC50 math coprocessor, which I installed
succesfully in my Mega Midget Racer (clocked at 33 MHz). I have tried
clocking my FPU at 28 to 50 MHz and it all worked just fine. I have a
MC68030-33 CPU. I don't know why my FPU has an XC (my original 33MHz FPU
was label MC68882-33), but it seems to work fine on my system. Maybe you
just have a bad chip.

Stefan

P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)

Newsgroup: sci.electronics
document_id: 53720
From: mniederb@pws2.itr.ch (Niederberger Markus)
Subject: Characterization of opamps

Hi,

Right now I should do some characterization of opamps. Because I don't  
have
special equipment for this task, I have to do this job with relativly  
simple
equipments (Frequency sweeper, DSO, etc.). 
Does anyone know good test circuitry for characterization of opamps? 
Especially for measuring open-loop gain, phase margin, PSSR, CMMR and so  
on.
Are there any books or application notes on this subject available?

Please reply vi e-mail or nn.

Thanks
Mark

__________________________________________________________________________ 
_____
Mark Niederberger
E-mail: mniederb@itr.ch
__________________________________________________________________________ 
_____

Newsgroup: sci.electronics
document_id: 53721
From: hjkim@hyowon.pusan.ac.kr (Hojoong Kim)
Subject: Looking for Electronics Dept Info in Austrailia

Hi Netters!

I am looking for the list of universities in Austrailia, which has electronics department. 
I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
But I don't have any information about Austrailian Universities.
Can anybody recommend a good university in communication area?
Any comments will be welcomed!

Bye.

Jaehyung Kim


Newsgroup: sci.electronics
document_id: 53722
From: jgd@dixie.com (John De Armond)
Subject: Re: What do Nuclear Site's Cooling Towers do?

nagle@netcom.com (John Nagle) writes:

>>Great Explaination, however you left off one detail, why do you always
>>see them at nuclear plants, but not always at fossil fuel plants.  At
>>nuclear plants it is prefered to run the water closed cycle, whereas
>>fossil fuel plants can in some cases get away with dumping the hot
>>water.  As I recall the water isn't as hot (thermodynamically) in many
>>fossil fuel plants, and of course there is less danger of radioactive
>>contamination.

Actually the reasons you don't see so many cooling towers at fossil plants are
1) fossil units (multiple units per plant) are generally smaller than
nuclear plants.  300 MWe seemed to be a very popular size when many
fossil plants were built.  The average nuclear plant is 1000 MWe.  2) many
fossil plants were grandfathered when water discharge regulations were
adopted ("why those old dirt burners can't harm anything, let 'em go.").  
3) powered draft cooling towers, low enough to the ground to be generally
not visible from off-site, are quite popular with fossil plants.  4) fossil
plants used to get much less regulatory attention than nuclears.

>       Actually, fossil fuel plants run hotter than the usual 
>boiling-water reactor nuclear plants.  (There's a gripe in the industry
>that nuclear power uses 1900 vintage steam technology).  So it's
>more important in nuclear plants to get the cold end of the system
>as cold as possible.  Hence big cooling towers.  

>       Oil and gas fired steam plants also have condensers, but they
>usually are sized to get the steam back into hot water, not most of the
>way down to ambient.  Some plants do cool the condensers with water,
>rather than air; as one Canadian official, asked about "thermal 
>pollution" de-icing a river, said, "Up here, we view heat as a resource".  

Actually the condensing environment is essentially the same for plants
of similar size.  The issues are the same regardless of where the 
heat comes from.  Condensers are run at as high a vacuum as possible in
order to reduce aerodynamic drag on the turbine.  The condenser pressure is
normally water's vapor pressure at the condensing temperature.  It is
desirable that the steam exhaust be free of water droplets because 
moisture in the steam causes severe erosion damage to the turbine 
low pressure blades and because entrained water moving at high velocity
causes erosion of the condenser tubes.  The coldest and thus lowest
pressure condensing environment is always the best.  

A related issue is that of pumping the condensate from the hotwell (where
the water ends up after dripping off the condenser tubes.)  Since the
condenser is at a very low pressure, the only force driving the 
condensate into the hotwell pumps is gravity.  If the condensate is too 
hot or the gravity head is too low, the condensate will reflash into
steam bubbles and cause the condensate pumps to cavitate.  This is a
particularly destructive form of cavitation that is to be avoided at all
costs.  

The hotwell pumps are located in the lowest point in the plant
in order to provide a gravity head to the pumps.  How much lower 
they must be is a function of how hot the water is allowed to get in
the hotwell.  Typically hotwell temperatures run between 100 and 120 
degrees depending on the temperature of the river water (this term is
used to describe the river grade water even when the cooling tower
system is operating in closed loop mode and essentially no river water
is pumped.)  When the river water temperature is high in the summer,
operators will typically allow the hotwell level to rise in order 
to provide more gravity head.  There is a tradeoff involved since higher
hotwell levels will encroach onto the condensing tubes and reduce the
condenser area.

At least in the East and elsewhere where moisture actually exists in the
air :-), the river water will almost always be cooler than the discharge
water from the cooling towers.  The temperature of the discharge water
from the cooling towers is set by the ambient air temperature and
humidity.  It is very rare in the East to hear of actual river water
temperatures exceeding 70 degrees.  A vast difference from the typical
"95-95" days (95 degrees, 95% humidity) we see routinely in the East.
It is not unusual, particularly where the econazis have been successful
in clamping rigid discharge water temperature limits on a plant, for the
plant to have to reduce the firing rate when the air temperature gets
too high and the condenser cannot handle the heat load without excessive
pressure.

>       Everybody runs closed-cycle boilers.  The water used is 
>purified of solids, which otherwise crud up the boiler plumbing when
>the water boils.  Purifying water for boiler use is a bigger job than 
>cooling it, so the boiler water is recycled.

True.  Actually secondary plant (the part that makes electricity and
feeds feedwater to the boiler) water chemistry has been the bastard 
stepchild until recently and has not gotten the respect it deserves.
The plant chemists have just in the past decade or so fully understood
the costs of impure water.  By "impure", I mean water with a few
dozen extra micromho of conductivity and/or a few PPM of dissolved
oxygen.  Secondary water is now typically the most pure one will 
find outside the laboratory.

John
-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine(TM) | Interested in high tech and computers? 
Marietta, Ga                         | Send ur snail-mail address to 
jgd@dixie.com                        | perform@dixie.com for a free sample mag
Lee Harvey Oswald: Where are ya when we need ya?

Newsgroup: sci.electronics
document_id: 53723
From: marrevola@rediris.es
Subject: Re: What is Zero dB????

In article <1993Apr6.132429.16154@bnr.ca>, moffatt@bnr.ca (John Thomson) writes:
> Joseph Chiu (josephc@cco.caltech.edu) wrote:
> 
> : And the measure of current, Amp, is actually named after both the AMP company
> : and the Amphenol company.  Both companies revolutionized electronics by
> : simulatenously realizing that the performance of connectors and sockets 
> : were affected by the amount of current running through the wires.
> 
> Sorry.  The unit for current is the AMPERE which is the name of a french-man
> named AMPERE who studied electrical current.  The term AMP is just an abbreviation
> of it.  The company AMP came after the AMPERE unit was already in use.
>   
> : The Ohmite company was the first to characterize resistances by numbers, thus
> : our use of the Ohms...
> 
> I don't know about this one, but it doesn't sound right.
Are you (two) joking?
Is the entire Internet flaming you (two)?
Ahh!, now I remember that Ohmite company was the first introducing "the pink
colored resistor", only for electronics working females ;-)
-- 
Manuel Arrevola Velasco   ||||| True e-mail: manolo@taf.fundesco.es |||||
DoD #1033


Newsgroup: sci.electronics
document_id: 53725
From: webb@itu1 (90-29265  Webber  AH)
Subject: Re: Adcom cheap products?

Aaron Lung (alung@megatest.com) wrote:
: >I was also sceptical about the amps being built in the far-east
: >  or where-ever.  But if you look in the amp and see what components
: >  they use and how it was designed, you can easily see why the
: >  amplifiers sound so brilliant.

: Good point...also, I wouldn't be surprised that the components
: they use off-shore are of inferior quality.  As long as it was
: properly designed and robust, premium components are used, it
: shouldn't matter where it is assembled.

Definately, I agree wholeheartedly.  If they can build the amp where
  the labour is not so expensive, they can afford to put decent
  components in and go to more effort to improve the design of the
  amplifier - as Adcom has done.

: >I cannot see why people say the amplifier won't last - not with
: >  those quality components inside.  Sure the amp runs very fairly
: >  hot - but that's how you get an amp to sound incredibly good.

: An amp that runs hot has no bearing on how it's gonna sound.
: The amp you have probably is running Class-A the whole day.

: Actually, I'd be wary of excessively hot amps, 'cauz even though
: the components inside may be rated to run that way, excessive 
: heat will dramatically shorten the life of *any* electronic component
: regardless of quality.  In fact, an amp that does run hot to the touch is
: because either the engineer or manufacturer of that amp wanted
: to skimp on heatsinking or cooling to save costs!  Hmmmmm....

Sure, I didn't mean to imply that because of the heat generated, the
  amp sounds good.  My Adcom GFP 535II runs fairly warm - not hot to
  the touch - but enough to satisfy me that the amp is running nicely.
I don't like it when an amp runs dead-cold.  It makes one think that
  the amp is doing nothing :)
The heatsinks that Adcom uses in their amps are certainly far for
  skimpy - they're massive things with heating vents both below
  and above.  More than enough to carry away excessive heat.

My opinions once again.

--
***********************************************************************
**    Alan Webber                                                    **
**                      webb@itu1.sun.ac.za                          **
**                      webb@itu2.sun.ac.za                          **
**                                                                   **
** The path you tread is narrow and the drop is sheer and very high  **
** The ravens all are watching from a vantage point near by          **
** Apprehension creeping like a choo-train up your spine             **
** Will the tightrope reach the end; will the final couplet rhyme    **
***********************************************************************

Newsgroup: sci.electronics
document_id: 53726
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: What's a good IC for RS232 -> TTL signals??

In article <C5nz60.99z@scraps.uucp>, frankh@scraps.uucp (Frank Holden KA3UWW) writes:
> In <C57zsC.9FL@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:
> 
>>I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
>>levels.  Something relatively inexpensive would be nice, too.  Anyone have
>>a suggestion??  Thanks.
> 
> Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
> you want.  They are selling it for about $3.50...
 
Digi-Key also sells Quad Line Receivers, parts DS1489AN (68cents) and DS1489N
(48cents).  A Quad Line Driver, part DS1488 (48cents), is also sold.  I guess
if you don't won't to supply +12V, the chips with the pump-up circuitry might
be worth the extra cost.  But 1488's and 1489's are available at your friendly
neighborhood RS, parts MC1488 (276-2520) for $1.29 and MC1489 (276-2521) for
$1.29.
 
Jeff White          jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
document_id: 53727
From: conrad@spva.ph.ic.ac.uk (Conrad Winchester)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu>, st1my@rosie.uh.edu (Stich, Christian E.) writes:
-| I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
-| 68030 + 68882 with capability to clock the FPU separately).  Previously
-| a MC68882RC25 was installed and everything was working perfectly.  Now the
-| systems displays a yellow screen (indicating a exception) when it check for
-| the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
-| fine, but with the XC68882 even at 25 MHz it does not work.  The designer
-| of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
-| might help, but that didn't change anything.  Does anybody have some
-| suggestions what I could do?  Does this look like a CPU-FPU communications
-| problem or is the particular chip dead (it is a pull, not new)?
-| Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
-| that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
-| Are there any MC68882RC33?
-| 
-| Thanks
-| 	Christian 
-| 


             Have you changed the crystal that clocks for the FPU. If you
   haven't then it won't work.


               Conrad

Newsgroup: sci.electronics
document_id: 53728
From: agodwin@acorn.co.uk (Adrian Godwin)
Subject: Re: Single chip receiver for FSK?

In article <C5L0xM.E25@law7.DaytonOH.NCR.COM> jra@law7.DaytonOH.NCR.COM (John Ackermann x 2966) writes:

>My goal is to come up with an inexpensive design for a receiver "back
>end" with IF input on one end and an FSK demondulator on the other.  I'm
>particularly interested in ways to use a higher IF than 10.7 -- do any
>current chips work up to, say 150MHz with internal downconversion so a
>normal IF filter can be used?
>

GEC/Plessey specify a series of FM demodulators (SL1454 etc) for use in
satellite TV receivers : 150 or 600MHz in, 10MHz of baseband video out.
I think there's also a related data slicer / clock recovery circuit intended
for use in DMAC decoders, though that isn't used in the most common 
implementation - it may not be in volume production.

The most easily available components probably vary with local satellite
standards, and I think the european systems vary rather widely from those
in the US - so it may be worth investigating locally-available receiver
designs to find out what's in common use.

-adrian


-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.

Newsgroup: sci.electronics
document_id: 53729
From: andrei@labomath.univ-orleans.fr (Andrei Yakovlev)
Subject: References to switched-capacitor filter ICs wanted.


   Hi All!

   I would like to know what are the popular ICs of the type, their capabilities
(# of channels et.c.) and prices :-)

   Great thanks,

 Andrew.

Newsgroup: sci.electronics
document_id: 53730
From: bills@inqmind.bison.mb.ca (Bill Shymanski)
Subject: Re: Dmm Advice Needed

kolstad@cae.wisc.edu (Joel Kolstad) writes:

> In article <734953838.AA00510@insane.apana.org.au> peter.m@insane.apana.org.a
> >
> >If you are going to use one where it counts (eg:aviation, space scuttle, 
> >etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
> >for every other use you can buy a cheapie.
> 
> My Beckman died a few days ago, thanks do about a 4 or 5 foot drop onto a
> lab table.  !@#!@$#!@$@#$  Probably not indicative of anything, but I've
> already filled out the requisition for a Fluke 87. :-)
> 
> Oh yeah, and sometimes our measurements here do count.  Not often, but often
> enough that I want at least _one_ good meter!
> 					---Joel Kolstad
   
We used to buy Beckman 110 and HD110 ("ruggedized") versions for use
by electricians in the steel mill where I work.   After a while we
got round to filling all the current-input jacks with silicone -
electricians have a regrettable habit of not checking where the last
guy left the leads before using a 3 1/2 digit 0.5 % autoranging $400
meter to check if a fuse is good or not. Its very hard on meters
(and electricians) when you put the milliamp shunt across a 600 volt
bus. 
  But that's not why we stopped buying Beckmans - after a while a 
lot of them got "funny" in the LCD display.  A black stain would
spread from one edge, or else they'd come adrift from those
Zebra connectors and fail to operate.    Now we buy Flukes, the
low-end 20 series mostly ( and we still fill the amp jack with 
silicone). 
  What the world needs is a meter that won't let you change ranges or
turn it on/off with a lead stuck in the amps jack - a little bit of
clever plastic detailing would take care of this and make the world
safer for electricans, anyway.
   Not that I've ever put a meter on the wrong range into a live 
circuit, no, not me...not more than a dozen times, anyway....
    Bill


bills@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 53731
From: mdgoodma@apgea.army.mil (Malcolm D. Goodman <mdgoodma>)
Subject: Sale -- Fiber Optic Modems, RF Modem, etc -- Best Offer


PLease take these and use them.  Take advantage of me... I really
don't know what they are worth.

Qty 2  -  Canoga Perkins Fiber Optic Modems, Model 2250, RS-422
          Interface, appear new.  I have powered up but that's all,
          I have not used them and I cannot tell you whether they
          work or not.    
                                 Make Offer.........

Qty 1 -   ISC Datacom RF Modem, Model 1056-TX1-RX5-SM-120, Interface
          RS-449, Internal Fan, powers up fine but otherwise condition
          unknown, Phone # for the company is 408-747-0300.

                                 Make Offer ............

Qty 1 -   Motorola UDS  212 A/D  Modem, RS-232 interface appears to work
          but I have not and cannot check it.  

                                 Make Offer  .............

Thanks and please buy this stuff or it goes out the door

Mack
mdgoodma@cbda8.apgea.army.mil
.

Newsgroup: sci.electronics
document_id: 53732
From: krouth@slee01.srl.ford.com (Kevin Routh)
Subject: F.Y.I.: ImageWriter to Windows...

[ Article crossposted from comp.windows.ms ]
[ Author was Kevin Routh ]
[ Posted on 19 Apr 1993 12:35:55 GMT ]

For your information:

I hooked up my ImageWriter I to my COM1 serial port and used the C-Itoh
8510 driver in Windows 3.1.  The cable I am using is a straight-thru
cable connected to a Null Modem Adapter I got at Radio Shack (catalog
#26-1496a) for $4.95.  It seems to work fine with both DOS and Windows.
I used the following command in DOS

	C:\DOS\mode COM1:9600,n,8,1,p

and set up the port the same way in the Windows Ports setup.

the Null Modem connections are as follows:

	1	to	1
	2	to	3
	3	to	2
	4	to	5
	5	to	4
	6+8	to	20
	20	to	6+8
	7	to	7

I printed from several applications and all seems OK.  

-- 
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244



--
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244


--
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244


Newsgroup: sci.electronics
document_id: 53733
From: sean@dip1.ee.uct.ac.za (Sean Borman)
Subject: INFO WANTED : Graphics LCD displays


Hi there

Does anyone know how to get hold of data as well as stock of the
LCD displays used in the NINTENDO GAMEBOY handheld TV game machines?

Any information wouold be MOST appreciated.

Please e-mail any replies to 

arawstorne@eleceng.uct.ac.za

thanks

Alex

Newsgroup: sci.electronics
document_id: 53734
Subject: PACE MODEM 
From: mora@verdi.cineca.it (Stefano Mora)

Hi,
I've got a PACE MODEM , Series Four 2400s ( made in England by
PACE Micro Technology ) with a broken power supply .
So I'd like to know :

- the voltage and current values of the original 
  power supply PS1001.
- the pinout of the power supply connector.
- the pinout of the USER PORT and how to use it.

Many thanks in advance to all the people help me.
Please post the reply also to my e-mail..........

+--------------------------------------------------+
|                                                  |
|  Sender: Stefano Mora                            |
|  eMail : mora@verdi.eng.unipr.it                 |
|                                                  |
+--------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53735
From: gould@waterloo.hp.com (Dan Gould)
Subject: Telephone Controlled Power Bar Needed

I would appreciate some help in locating a telephone controlled power bar
for my PC. The unit would power up the PC when the telephone rings and
keep it up as long as the telephone connection is present.

I also need to be able to power up this same PC through the use of an external
timer. I can supply power or a contact closure to do this.

I will summarize and post the results of this query here.

Thank you.



--
Dan Gould
gould@waterloo.hp.com

Newsgroup: sci.electronics
document_id: 53736
From: kehoe@netcom.com (Thomas David Kehoe)
Subject: Re: How starters work really

>>So when you turn on the power, this causes the bulb to work like a neon, 
>
>Imprecise. This description
>
> 1. ignores the role of the ballast,
> 2. misrepresents the heating effects in the starter.
>
>The bimetalic strip cools down immediately after the contacts

I've been thinking of sending into Mad magazine an idea for a 
parody, of those books entitled "How Things Work" that
engineers buy their sons, which explain how engines, elevators,
flourescent lights, etc. work.

The parody would be "How Things Really Work."  Under "Canned
Food", on the left page you'd see the description from 
"How Things Work": gleaming stainless steel equipment
pasteurizing the food to precisely the right temperature,
then sealing the can in an oxygen-free environment, etc.

On the right page you'd see "How Things Really Work":
brain-dead workers sending disgusting food to the
gleaming equipment -- rotting vegetables, parts of
animals people don't eat, barrels of sugar and chemicals.

Under "Elevators" you'd see (on the left) computer geniuses
working out algorithms so that X number of people
waiting for Y elevators will get to Z floors in the shortest
time.  On the right, you'd see giggling elevator controllers
behind a one-way mirror in the lobby choosing which people
appear to be in the biggest hurry and making them wait longest.
-- 
"Why my thoughts are my own, when they are in, but when they are out
they are another's." - Susannah Martin, hanged for witchcraft, 1692.
Thomas David Kehoe          kehoe@netcom.com         (408) 354-5926

Newsgroup: sci.electronics
document_id: 53737
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: History question

In article <2775@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:
>
>I recall reading of a phonograph which used mechanical amplification.
>Compressed air was squirted out of a valve which was controlled by the
>pickup.  The result was noisy and distinctly lo-fi, but much louder
>than a conventional phonograph.  It tended to wear the disks out
>pretty quickly though.

This was the Pathe you are thinking of, although there were other imitators.
It didn't wear the disks any more than conventional acoustic designs, but
it did have a high noise level due to the continual hiss of escaping air.
There are a lot of them still operating, and they are pretty ingenious.

There was a pneumatic amplifier designed by Alexander Graham Bell, as well,
but I don't know if it was ever constructed.
--scott

Newsgroup: sci.electronics
document_id: 53738
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?


Call a friend long distance, collect.  Ask to speak with yourself.  When
the operator asks for you, you won't be there, so ask the operator to leave
your number.  She'll read it out in the clear.
--scott

Newsgroup: sci.electronics
document_id: 53739
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: subliminal message flashing on TV

In article <7480237@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> Hi.  I was doing research on subliminal suggestion for a psychology
>> paper, and I read that one researcher flashed hidden messages on the
>> TV screen at 1/200ths of a second.  Is that possible?  I thought the
>> maximum rate the TV was even capable of displaying images was 1/30th
>> of a second.  (or 1/60th of a second for an image composed of only odd
>> or even scan lines)
>
>You are correct; the fastest "complete" image that could be presented on
>TV would be one field, which is 1/60 of a second (approximately).  Of course,
>the phrase "TV screen" is often thrown around in reference to any CRT
>display, so perhaps this researcher wasn't using normal TV rates.  Might
>even be a vector ("strokewriter") display, in which case the lower limit
>on image time is anyone's guess (and is probably phosphor-persistence limited).

Actually, a lot of this work used to be done with a CRT that had a beamsplitter
mounted in front, and a tachistoscope driving it.  The tachistoscope is really
just a slide projector with a very fast shutter.  Low tech, but it does the job.
--scott

Newsgroup: sci.electronics
document_id: 53740
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Mysterious MOSFET

I have a MOSFET pulled out of a Trygon power supply, for which I have no 
manual.  It's a Motorola part with a 1972 date code and the number

		285-4

which the Motorola folks assure me is a house number, which they can't
help me with.  Any suggestions from folks out there?  I can't put it on
a curve tracer to try to get an equivalent, since it's completely shot.
--scott

Newsgroup: sci.electronics
document_id: 53741
From: bakerjp1@netnews.jhuapl.edu (Baker John P. PDD x4895 )
Subject: How does "Differential Mode" GPS work???


>I understand that the new GPS boxes now have an option
>known as "differential ready".  Apparently land-based
>beacons tranmit GPS correction information to your GPS 
>receiver (with differential option installed).

>How does this system work?  What frequency is used for
>the land-based beacons?

>Thanks in advance,

>Charlie Thompson
>.

Here's a rough sketch of how the system works.  A reference station
with a very exactly known position computes the errors in the
incoming GPS signals.  These errors are due to several factors
including atmospheric distortion, SA (Selective Availability) time
dithering, etc.  The reference unit contains complex computational 
equipment to "back out" the errors in its position (since it knows
where it is already).  It then transmits these corrections on a 
broadcast which is available to any number of relatively local
receivers.  If the receivers are nearby (<300km) and are using
the same satellites as the reference unit, the errors should be very
similar for the reference unit and the receiver unit.  Thus, the
receiver unit may apply the corrections calculated by the reference
unit.

The US Coast Guard is currently (as far as I know) installing a series
of coastline transmitters for differential GPS.  These stations will
use existing radio towers.  I believe the frequency is to be approximately
305 kHz.  There are many other private corporations offering DGPS signals
on different frequencies.  For example, PinPoint ((310)-618-7076) offers
correction signals and receiver units using an FM broadcast system
which has stations all across the US.

The correction codes are usually transmitted using the RTCM 104 format.
Advertised accuracies espouse 1 to 5 meter errors.


-------------------------------------------------------------------------
John P. Baker                   | My opinions are my own.  I don't know
Johns Hopkins University        | anyone else who wants them, anyway.
Applied Physics Laboratory	|
Laurel, MD  20723               | bakerjp1@aplcomm.jhuapl.edu
--------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53742
From: mjhill@eos.ncsu.edu (MICHAEL JAMES HILL)
Subject: New applications of electronics



	I'm looking for brief information on new
applications of electronics (or new electronics in
applications.) If you know of any interesting new
stuff, I would be intrested in hearing about it.

			Thanks, MJH

Newsgroup: sci.electronics
document_id: 53743
From: domain@cbnewsf.cb.att.com (george.d.hodge)
Subject: Dayton Hamfest


Some weeks ago, someone posted an article telling when and where
a hamfest and computerfest was going to be help in Dayton, OH.
Unfortunately, I lost the article and I was wondering if someone
could repost it.

I believe it was being held the 23,24,and 25 of this month at
the Dayton convention center but I'm not sure.

Any help and more details would be greatly appreciated.

		george.d.hodge
		domain@cbcat.att.com


Newsgroup: sci.electronics
document_id: 53745
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: What do Nuclear Site's Cooling Towers do?

> I really don't know where to post this question so I figured that
> this board would be most appropriate.

try sci.energy

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
document_id: 53746
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: 16 bit serial converters

Someone was looking for these a few weeks ago - check out comp.dsp
Mike.

Newsgroup: sci.electronics
document_id: 53747
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Getting rid of screen wiggles?

In article <1qpj5t$itg@vela.acs.oakland.edu>, eabyrnes@vela.acs.oakland.edu
(Ed Byrnes) wrote:
> 
> My monitor display has a bad case of the wigglies. I have a good ground. I
> live in an old house and I have replaced much of the wiring. I have two
> EMI filters on the computer, the monitor plugs into the computer. When
> fluorescent lights are on upstairs, the display jiggles, when motors run
> in the house, the display jiggles, when incandescent lights are on in the
> kitchen the display jiggles.  I could bring a separate line from the
> breaker box, and use it only for the computer, would this do it? EMI
> doesn't only travel the 110 volt line though. Should I shield the back of
> the monitor? Ground a grid or plate? 
> Your expertise is appreciated. Thanks very much!  Ed Byrnes


Aaahh... a problem very near and dear to my heart. In our case, other
monitors cause this problem - the deflection coil of other monitors to be
specific. Have also seen a monitor backed up to a fuse panel exhibit this
problem. This sounds like your problem since flourescent lites, motors, etc
several 10s of feet away seem to me to be too far to cause it, but the
juice running to them must pass nearby your monitor. Fusebox on other side
of wall maybe?
We started spec'ing Panasonic CT-1331Y video monitors (3 switchable input
lines(vid & aud) S-VHS on one) <$400. This stopped the wavy interference
effect on the computer monitor next to it. 
Now on to your problem. You need what is known as mu shielding (very
common, in fact almost mandatory on electrostatic deflection type
O'scopes).
I talked to a EE prof. He said get a coffee can, cut both ends off, mount
around deflection coil of interfering monitor. 
BE CAREFUL TO AVOID ALL HIGH VOLTAGE CIRCUITRY. ESPECIALLY THE THICKER HIGH
VOLTAGE ANODE LEAD USUALLY COLORED RED. IF YOU KILL YOURSELF, DON'T
BLAME/SUE ME!!! USE PLASTIC OR OTHER NON-CONDUCTING STAND-OFFS AND SUCH TO
MOUNT CAN.
Now, I would assume that what is good for keeping mag fields in is also
good at keeping them out, so hopefully this'll work by mounting shield on
monitor being interfered with as well. If not, start shielding those other
sources.

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
document_id: 53748
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Food Dehydrators

  Does anybody out there have one of those food dehydrators I've been seeing
all over late-night TV recently? I was wondering if they use forced air, heat,
or both. If there's heat involved, anybody know what temperature they run at?
My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
and a heater. Seems to me you should be able to throw a dehydrator together
for just a few bucks. Heck, the technology is only what? 1,000 years old?

John


Newsgroup: sci.electronics
document_id: 53749
From: ski@wpi.WPI.EDU (Joseph Mich Krzeszewski)
Subject: Re: Need to find out number to a phone line

Well, this is my second try at posting on this subject. Here goes...
	In Texas (Corpus Christi at least) if you pick up the phone and dial
	890 the phone company will read the number of the phone you are on 
	back to you. I believe the service department uses this to make
	certain they are repairing the correct lines when they open the BIG
	junction boxes. I don't know if it will work but you can give it a
	try. Good luck.
 


Newsgroup: sci.electronics
document_id: 53750
From: billq@ms.uky.edu (Billy Quinn)
Subject: Suggestions  on Audio relays ???

I built a little project using the radio shack 5vdc relays to switch
audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
most of the common things one is supposed to do when using relays and
nothing seemed to get rid of the clicks.


My question is:

	Is there a good relay/relay circuit that I can use for switching
audio, so that there will be *NO* noise of any kind on the audio lines.


I will appreciate any advice or references to advice.  Also, exact part
numbers/company names etc. for the relays will help!

Thanks!


-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*

Newsgroup: sci.electronics
document_id: 53751
From: levy@levy.fnal.gov (Mark E. Levy, ext. 8056)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <1qngqlINNnp8@shelley.u.washington.edu>, whit@carson.u.washington.edu (John Whitmore) writes:
> In article <C5L5x0.KJ7@vcd.hp.com> johne@vcd.hp.com (John Eaton) writes:
>>-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:
> 
>>During the nuclear fission reaction the uranium fuel can get hot enough
>>to melt. When this happens the liquid uranium is pumped to the cooling
>>tower where it is sprayed into the air. 
...
>>Contact with the cool outside air
>>will condense the mist and it will fall back to the cooling tower floor.
>>There it is collected by a cleaning crew using shop vacs and is then
>>reformed into pellets for reactor use the next day.

Another April 1 posting.  Ahhh.

================================================================================
[ Mark E. Levy, Fermilab          |                                            ]
[ BitNet:   LEVY@FNAL             | Unix is to computing                       ]
[ Internet: LEVY@FNALD.FNAL.GOV   |       as an Etch-a-Sketch is to art.       ]
[ HEPnet/SPAN: FNALD::LEVY (VMS!) |                                            ]
================================================================================


Newsgroup: sci.electronics
document_id: 53752
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr14.181738.18472@bmers95.bnr.ca> alee@bmerh794.bnr.ca (Louis Leclerc) writes:
>
> In article <34263@oasys.dt.navy.mil> you write:
> >VA, CT, Wash DC  and I think BC Canada where I've heard they actually
> >use Radar detector detectors.
>
> Nope, not in British Columbia.  Detectors are legal here in BC, I've even
> got one.
>
> In Alberta and Ontario they're illegal, and detection devices are sometimes
> used.  I've heard the police in Ontario prefer a much more direct method of
> detection.  Just trigger the radar gun, watch for people slamming on the
> brakes, and search the car.
>
>
> David Lee
> leex@sfu.ca
>

Detectors are legal in Alberta, the old law was overturned a long time ago.

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
document_id: 53753
From: harton@owlnet.rice.edu (Tracy Brian Harton)
Subject: Wireless Transmitter/Receivers at RS


Does anyone know what frequencies the wireless transmitter/receiver
microphone systems that Radio Shack sells operate at?  I've tried
everything short of opening one up (not actually owning one makes
this difficult...) and just looking..  Any help would be greatly
appreciated..  These systems are designed for wireless PA systems, etc..
 
 
					Thanks,
	 
							Tracy


Newsgroup: sci.electronics
document_id: 53754
From: st1my@rosie.uh.edu (Stich, Christian E.)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu>, st1my@rosie.uh.edu (Stich, Christian E.) writes...
>I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
>68030 + 68882 with capability to clock the FPU separately).  Previously
>a MC68882RC25 was installed and everything was working perfectly.  Now the
>systems displays a yellow screen (indicating a exception) when it check for
>the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
>fine, but with the XC68882 even at 25 MHz it does not work.  The designer
>of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
>might help, but that didn't change anything.  Does anybody have some
>suggestions what I could do?  Does this look like a CPU-FPU communications
>problem or is the particular chip dead (it is a pull, not new)?
>Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
>that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
>Are there any MC68882RC33?
> 
>Thanks
>	Christian 
> 

It appears as if the problem is related to the 68882/50's need for very fast
(and clean) signal transitions.  I got some email (Vielen Dank, Thomas) stating
that Motorola provides a solution for this problem in their 68030 manual.  
Since my manual (1989) predates the 50 MHz 68030/68882s I couldn't find it.
Could someone please email me the specifics?
		Thanks
			Christian

Newsgroup: sci.electronics
document_id: 53755
From: mont@netcom.com (Mont Pierce)
Subject: Re: 8051 Microcontroller

In article <1qppr5INNaqa@dns1.NMSU.Edu> mcole@spock (COLE) writes:
>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>there know of any good FTP sites that might have compiliers, assemblers,  
>etc.?

Well, it's not an FTP site, but I got an 800 number for Signetics BBS.

The Signetics BBS contain some pretty good items for the 8051.  I am
currently using the following files which I downloaded from them:

    ml-asm51.zip      MetaLink's 8051 family macro assembler
    bootstrp.zip      Hex file Load-and-Go using 8051 uart
                      (allows you to download your program into a RAM
                       and then execute from RAM.  Works great.  Tell
                       me if you want more details).
    tutor51.zip       TSR for 8051 feature help screens
    
They have lots of coding examples, assemblers, and misc. tools.

Signetics BBS numbers are:    (800) 451-6644
                              (408) 991-2406

Have fun,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53756
From: borowski@spk.hp.com (Don T. Borowski)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

Dean Anneser (anneser@pwa-b.uucp) wrote:
: My 9 yr old son has signed up to do a science report on batteries.  I was
: wondering if anyone could provide me with some information as to how to
: construct a home-built battery.  In my grade school days, I remember seeing
: the 'ice cube tray' version, but I don't remember what to use as a good
: electrolyte or what the easily obtainable metals were.  
: 
: Thank you in advance.
 
I remember watching a whole "Mr. Wizzard" program on this subject when
I was a kid.  The battery constructed on the program which made the 
biggest impression on me, and generated the most power, was made using
a galvanized bucket (for the zinc) and a copper toilet tank float.  The
electrolyte was sauerkraut!


Donald Borowski    WA6OMI    Hewlett-Packard, Spokane Division
"Angels are able to fly because they take themselves so lightly."
                                       -G.K. Chesterton


Newsgroup: sci.electronics
document_id: 53757
From: mont@netcom.com (Mont Pierce)
Subject: Need pinouts for a G8870 dtmf decoder chip


I bought this chip from Suncoast Technology and tried to build their
dtmf decoder circuit.  But it's not working...

If anyone has the pinouts and possibly the voltage specs I'd sure
appreciated it.  If someone could fax, email, or snail mail a copy
of the spec sheet for this chip that would be even better. :)

Please email me if you can help.  

Thanks in advance,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53758
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Cicuit Cellar Ink - Extras 4 Trade

Fellow Info-junkies,
  I have an extra CCI #27 (Real Time Programming/Embedded Sensors &
Storage) and an extra CCI #32 (Voice control of telescope, among other
articles). No labels. No torn, cut-up, or missing pages.

Would like to trade for CCI # 26, or CCI # 23, or CCI # 19 in same
condition (Labels OK).

I mail mine you mail yours mutual trust kinda thang OK?
You don't actually throw them away, do you?

Thanx,
Jeff Babb
babb@sciences.sdsu.edu

Newsgroup: sci.electronics
document_id: 53759
From: garyg@warren.mentorg.com (Gary Gendel)
Subject: Re: Need to find out number to a phone lin

In article 1qub4mINN7r3@rave.larc.nasa.gov, kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>>
>>Greetings!
>>      
>>        Situation:  I have a phone jack mounted on a wall.  I don't
>>                    know the number of the line.  And I don't want
>>                    to call up the operator to place a trace on it.
>>
>>        Question:   Is there a certain device out there that I can
>>                    use to find out the number to the line?
>
>
>Call a friend long distance, collect.  Ask to speak with yourself.  When
>the operator asks for you, you won't be there, so ask the operator to leave
>your number.  She'll read it out in the clear.
>--scott

Even easier, my area supports 311.  Dial this and a recording recites your number.
Phone techs use it to verify an installed line.
---
			Gary Gendel
Vice President:				Current consulting assignment:
Genashor Corp				Mentor Graphics Corporation
9 Piney Woods Drive			15 Independence Boulevard
Belle Mead, NJ 08502			Warren, NJ 07059

phone:	(908) 281-0164			phone:	(908) 604-0883
fax:	(908) 281-9607			email:	garyg@warren.mentorg.com




Newsgroup: sci.electronics
document_id: 53760
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does someone know what is the news group for IEEE.

       yxy4145@usl.edu     Thanks a lot.


Newsgroup: sci.electronics
document_id: 53761
From: khairon@usc.edu (Rosli Bin Khairon)
Subject: Looking for Address of Noise Cancellation Tech.

      I am new to this newsgroup so I apologise if this is not the appropriate
forum to ask this question. I am looking for the address of Noise Cancellation
Technologies. It is rather important. So if you can help me in this regard,
please do. Thank you.



    




-- Rosli
Khairon@aludra.usc.edu

Newsgroup: sci.electronics
document_id: 53762
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Motorola XC68882RC33 and RC50

In article <sgberg.23xu@charon.bloomington.in.us> sgberg@charon.bloomington.in.us (Stefan Berg) writes:
>... I don't know why my FPU has an XC (my original 33MHz FPU
>was label MC68882-33), but it seems to work fine on my system...
>P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)

The rule for the designations is that if it says MC, that means it works
*exactly* the way the datasheet/book specifies.  If it says XC, that means
there is at least one known bug.  Often these bugs are small and obscure;
you might never run into them in practice.

At least Motorola admits it, unlike certain other companies...
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53763
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: Mysterious MOSFET

In article <1qug3sINN90g@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:

>I have a MOSFET pulled out of a Trygon power supply, for which I have no 
>manual.  It's a Motorola part with a 1972 date code and the number

>               285-4

>which the Motorola folks assure me is a house number, which they can't
>help me with.  Any suggestions from folks out there?  I can't put it on
>a curve tracer to try to get an equivalent, since it's completely shot.
>--scott
Since your MOSFET is a 1972 vintage, it's probably not a very good one by 
today's standards.  If you have an idea about its voltage and current 
ratings, e.g. 60VDC @ 6A, you can probably get away with replacing it with 
anything with better specs.  Early MOSFETS had a gate-source voltage rating 
of approximately +/- 20 VDCmax, and they would usually turn completely "ON" 
at +10VDC.  Otherwise, MOSFETS are not really mysterious -- they're more or 
less voltage controlled current sources.  If the MOSFET in your circuit is 
used as an open-loop, voltage controlled current source, you may have to 
experiment with various gain-altering techniques.

Bill Willis     willisw@coe-nw.clemson.edu
(803) 656-5550

Newsgroup: sci.electronics
document_id: 53764
From: kubovich@iastate.edu (Mark W Kubovich)
Subject: Common-mode noise and small signals

I have never worked with really small signals before and have a few 
questions about low level noise.  I have noticed that the waveform 
synthesizer that I am using (Analogic 2020) has some relatively large
common mode noise on it.  I am using this synthesizer to 'null' out another
transient waveform and am amplifying the difference (~200uV) several hundred 
times.  The 2020 has about 1-3 mVp-p of common mode noise and this tends to
make my measurements hard to repeat.  (The noise is not quite in sync with 
line frequency, and on a spectrum analyzer, the main component is about 64Hz).

How can I get rid of the noise?  When I look at the spectrum using an
HP 3582A (audio range analyzer), the noise goes away the minute I switch to 
'isolation' on the input.  I am guessing the anlayzer has a diff amp on the 
input since it will read accurately down to DC.

Also, if I use a differential amplifier (IA) to solve the problem, 
how important is it to use one of these 'shield drivers' (an amp connected 
to the shield in sort of a feedback loop to remove trouble caused 
by different cable capacitances)?  If anyone can suggest a good IC IA for 
use with transient signals with content from 1KHz to about 300KHz, I would
appreciate it.  

Newsgroup: sci.electronics
document_id: 53765
From: bday@lambda.msfc.nasa.gov (Brian Day)
Subject: Re: 8051 Microcontroller

mcole@spock (COLE) writes:

>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>there know of any good FTP sites that might have compiliers, assemblers,  
>etc.?

Try lyman.pppl.gov -- /pub/8051

-- 
Brian Day                                       bday@lambda.msfc.nasa.gov
New Technology, Inc.                            (205) 461-4584
Mission Software Development Division           Opinions are my own -

Newsgroup: sci.electronics
document_id: 53766
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: Dayton Hamfest

Yes, it is the 23, 24 and 25, in but does anyone have directions how to
get there after I get to Dayton.  Thanks

Wayne Martin


Newsgroup: sci.electronics
document_id: 53767
From: jkaidor@synoptics.com (Jerome Kaidor)
Subject: Re: electronic odometers (was: Used BMW Qu


    Just a few comments about the feasability of zipping up a bunch of miles
on your electronic odometer with an oscillator....

    I wouldn't expect to be able to do this.  Not because the engineers at BMW are
putting in anti-fraud logic, but just because an automobile is a noisy, hostile
environment for electronics, and I would expect the software to be conservative.

   If I were to design a microprocessor-based odometer/speedometer program,
it would have the following features ( just off the top of my head ):

         * Debouncing/deglitching  ( Is this a real pulse, or just a glitch? )
         * Smoothing:  The rate-of-change of speed cannot be too high:
                                This is a car, not an electron.
         *  Top speed limit:  Anything above 200MPH is ridiculous: must be
                                        electrical noise or contact bounce

    As for getting in and presetting the pins:  if this is the circuit board out of
a BMW dashboard, I seem to remember a single big chip with lotsa pins in the
middle of the card.  Good luck getting at the counter :-).

    I wouldn't expect a high input frequency to damage the meter:  remember, it's
probably damped so it can't move too fast, and is probably protected.  After all,
a car is an extremely hostile place for delicate electronics;  there used to be an
app note in the National Semiconductor Linear Databook that went into this
in good detail.

                               - Jerry Kaidor ( tr2!jerry@dragoman.com, jkaidor@synoptics.com )


                                  - Jerry Kaidor

Newsgroup: sci.electronics
document_id: 53768
From: 2575brooksr@vms.csd.mu.edu
Subject: NeXT cube board monitor cable ?

Hi all!
	Quick question.  Could someone please send me a pinout of
the cable that goes between a NeXT cube and the monitor?  Also,
I am interested in the video signal (sync type, horz/vert rate)
so any information on that would be greatly appreciated also.

Thanks!
Ryan Brooks					ryan@agnus.mcs.mu.edu

Newsgroup: sci.electronics
document_id: 53769
From: alung@megatest.com (Aaron Lung)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al

There is a number you can call which will return a synthesized
voice telling you the number of the line.  Unfortunately, for the
life of me I can't remember what it is. The telephone technicians
use it all the time.  We used to play around with this in our
dorm rooms since there were multiple phone lines running between
rooms.

sorry!

aaron


Newsgroup: sci.electronics
document_id: 53770
From: musone@acsu.buffalo.edu (Mark J. Musone)
Subject: MC SBI mixer

HI, I was wondering if anyone would be able to help me on twwo related
subjects. I am currently learning about AM/FM receivers and recieving
circuits. I understand a lot of things ,but a few things I am confused
abuot. The first is the MIXER, to mix the RF and local oscillator
frequencies to make the IF. Does anyone have any cicruit diagrams (as
simple as possible) for this kind of mixer? I have come across a
MC-SBL mixer chip But I have not been able to find it in any catalogs
(ACTIVE,etc...) 

Along the same note, are there any SIMPLE fm receiver circuits anyone
may have stashed away somewhere and they couold let me see?.

P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
ELECTRICAL DIAGRAMS would help a lot.
I have seen a lot of theory books with no circuits and a lot of
circuit books with no theory, but one without the other does not help.

				Thanks,

				Mark Musone

Newsgroup: sci.electronics
document_id: 53771
From: levy@levy.fnal.gov (Mark E. Levy, ext. 8056)
Subject: Sources for Intel D87C51FB?

I am in the midst of designing a project which requires two motors and an LED
illuminator driven with Pulse-width modulation.  I'm using the 8751, and
I understand that the -FB version has a programmable counter array that can
essentially be set and forgotten to do the PWM.  The problems is, that variant
is difficult to come by.  I need two or three of the D prefix (ceramic window)
version for development, and then lots of the P prefix (plastic OTP) for later
production.  I've tried Avnet, Arrow, and Pioneer.  They (might) have them, but
I'm looking for samples at this point, and they're not too willing to provide
them.  I would buy them, but these vendors have $100.00 minimums.

Any help is appreciated.

================================================================================
[ Mark E. Levy, Fermilab          |                                            ]
[ BitNet:   LEVY@FNAL             | Unix is to computing                       ]
[ Internet: LEVY@FNALD.FNAL.GOV   |       as an Etch-a-Sketch is to art.       ]
[ HEPnet/SPAN: FNALD::LEVY (VMS!) |                                            ]
================================================================================

Newsgroup: sci.electronics
document_id: 53772
From: jott@scarecrow.cse.nd.edu (John Ott)
Subject: Re: Pinout needed for TIL311

In article <segal.734995860@corolla7>, segal@rtsg.mot.com (Gary Segal) writes:
|> I've recently picked up some TIL311 display chips, but I can't find
|> any information on them.  It seems they are no longer made by TI, and
|> I don't have an old enough data book.  :-(
|> 
|> It appears to have a dot-matrix led display capable of showing one hex
|> digit.  It is in a 14 pin DIP package, but pins 6, 9, and 11 are not
|> present.
|> 
|> If you have any information on this part (pinout, power requirments,
|> functions, ...) please send me e-mail.
|> 
|> Thank You,
|> 
|> -- 
|> Gary Segal                             Motorola Inc.            
|> segal@oscar.rtsg.mot.com               Cellular Infrastructure Division
|> 	--- we are standing here only to gaze at the wind ---


pin      function
 1      led supply voltage
 2      latch data input b
 3      latch data input a
 4      left decimal point cathode
 5      latch strobe input
 6      omitted
 7      common gnd
 8      blanking input
 9      omitted
10      right decimal point cathode
11      omitted
12      latch data input d
13      latch data input c
14      logic supply voltage (5v)

LATCH STROBE INPUT, pin 5, when low, the data in the latches follow the data on the latch data
                             inputs.  When high, the data in the latches will not change.  If the
                               display is blanked and then restored while the enable input is high,
                               the previous character will again be displayed.

BLANKING INPUT, pin 8,    When high, the display is blanked regardless of the levels of the other
                              inputs.  When low, a character is displayed as determined by the data
                              in the latches.  The blanking input may be pulsed for intensity modulation.

LATCH DATA INPUTS, pins 2,3,12,13,   Data on these inputs are entered into the latches when the enable
                                          input is low.  The binary weights of these inputs are A = 1,
                                          B = 2, C = 4, D = 8

DECIMAL POINT CATHODES, pins 4, 10,   These LEDS are not connected to the logic chip.  If a decimal point
                                          is used, an external resistor or other current limiting
                                          mechanism must be connected in series with it.

LED SUPPLY, pin 1            This connection permits the user to save on regulated Vcc current by using
                                 a separate LED supply, or it may be externally connected to the logic
                                 supply (Vcc).

LOGIC SUPPLY (Vcc), pin 14      Separate Vcc connection for the logic chip

COMMON GROUND, pin 7,      This is the vegative termnal for all logic and LED currents except for the
                              decimal points.

John
jott@dickens.helios.nd.edu

Newsgroup: sci.electronics
document_id: 53773
From: tron@ux1.cso.uiuc.edu (Tron R.)
Subject: modulation over rf

I would like to modulate a 40KHz squarewave over rf. This is for a rf
remote control project. The squarewave has a high of 5 v and low of 0v.

thanks.

tron
-- 
        T
  T     T
  T  T  T
  T  T  T

Newsgroup: sci.electronics
document_id: 53774
From: morrow@cns.ucalgary.ca (Bill Morrow)
Subject: Need source for old Radio Shack stereo amp chip

Last week I asked for help in getting an old homemade amp working with
my Sun CD-ROM drive. It turns out that the channel I was testing with
was burned out in the amp. The other channel works fine.

So now I need a new amplifier chip. My local Radio Shack no longer
carries components! The chip is a 12 pin SIP (?) labelled with BA5406
and then "502 515" below that.

Does anyone have a source? Thanks,
-- 
Bill Morrow    Clinical Neurosciences, University of Calgary
e-mail: morrow@cns.ucalgary.ca voice: (403) 220-6275 fax: (403) 283-8770 
3330 Hospital Drive NW Calgary, Alberta, CANADA T2N 4N1

Newsgroup: sci.electronics
document_id: 53775
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In article <C5quI4.4CF@spk.hp.com> borowski@spk.hp.com (Don T. Borowski)  
writes:
> Dean Anneser (anneser@pwa-b.uucp) wrote:
> : My 9 yr old son has signed up to do a science report on batteries.  I  
was
> : wondering if anyone could provide me with some information as to how  
to
> : construct a home-built battery.  In my grade school days, I remember 

(snip!)

I haven't been following this, so I'm sorry if somebody already mentioned  
this, but you could grab a lemon (I think potatoes work too, but I'm not  
sure), a strip of copper, and a strip of zinc (I think you can get the  
metal in a hardware store or hobby shop, maybe??).  Stick the strips in  
the lemon (so they don't touch!) and you'll get a measurable voltage (not  
a lot, but, hey, it's a lemon :-)  ).  As I recall we had to hook  
something like ten of these things to get an appreciable amount of  
current, because of the mondo internal resistance, but if you just need a  
demo you might get it to run a tiny fan or something! :-)


Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
document_id: 53776
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Need pinouts for a G8870 dtmf decoder chip

In article <montC5qs9A.3wB@netcom.com> mont@netcom.com (Mont Pierce) writes:
>
>I bought this chip from Suncoast Technology and tried to build their
>dtmf decoder circuit.  But it's not working...
>
>If anyone has the pinouts and possibly the voltage specs I'd sure
>appreciated it.  

I presume it is the M-8870 from Teltone Corporation.

Pin	Description

1	+ input
2	- input
3	GS (gain select through use of feed back resistor)
4	Vref (reference voltage OUTPUT, about Vdd/2)
5	connect to Vss
6	connect to Vss
7	osc1 clock input
8	osc2 clock output (connect crystal across pins 7 and 8)
9	Vss
10	OE output enable (logic high allows data output)
11	Q1 data output
12	Q2 data output
13	Q3 data output
14	Q4 data output
15	StD Delayed Steering Output (any other company would call this 'data valid'.)
16	ESt Early Steering output, sort of like "I'm starting to hear a tone".
17	St/GT Steering input/guard time output
18	Vdd

Power Supply	: 4.75V min., 5.25V max.
Current		: 3.0mA Typ, 7.0mA max.

BUT.......

You really should have bought the Motorola part from me.  :-)
(I still have them in stock)

John



If someone could fax, email, or snail mail a copy
>of the spec sheet for this chip that would be even better. :)
>
>Please email me if you can help.  
>
>Thanks in advance,
>-- 
>Mont Pierce
>
>+-------------------------------------------------------------------------+
>| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
>|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
>|    modes: cw,ssb,fm                                                     |
>+-------------------------------------------------------------------------+



Newsgroup: sci.electronics
document_id: 53777
Subject: Pattern Generator wanted
From: grimwood@ccu1.aukuni.ac.nz (Tony Grimwood)

I repair a lot of monitors here, and I'd like to know where I can get a
pattern generator (or a circuit for one) that will provide MDA, EGA and VGA
signals. Using a whole PC to do this takes up too much space on my bench, and
is somewhat less than portable. I guess I could sit down and design something,
but I don't have the time right now - any (reasonable) suggestions would be
appreciated.

TNX

TG
-- 
Tony Grimwood, ZL1TTG			"Make no friendship with an elephant
Biomedical Engineering Services		 keeper, unless you have room to
University of Auckland			 entertain an elephant."
Auckland, New Zealand		       		 == Saadi of Shiraz ==

Newsgroup: sci.electronics
document_id: 53778
From: howeg@p4.cs.man.ac.uk (Monty Mole)
Subject: FM Transmitter

Can anyone please email a diagram or give me details of an ftp site where there
is a diagram of a simple, small fm mono voice transmitter for trasnmitting in
the 90-104 range (preferably above 100 Mhz). Only a short distance requiered,
and frequency variation no too important but must run from 9v or smaller DC
supply.

Thanx in advance

Monty.
-- 
    /\    /\     __   __  /_                            howeg@uk.ac.man.cs 
   /  \  /  \   /  / / / /  / /                         howeg@cs.man.ac.uk
__/    \/    \_/__/_/ /_/__/_/____________________________________________
____________________________/ Save The Vinyl!

Newsgroup: sci.electronics
document_id: 53779
From: alung@megatest.com (Aaron Lung)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>I built a little project using the radio shack 5vdc relays to switch
>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>most of the common things one is supposed to do when using relays and
>nothing seemed to get rid of the clicks.
>
>
>My question is:
>
>	Is there a good relay/relay circuit that I can use for switching
>audio, so that there will be *NO* noise of any kind on the audio lines.
>
>
>I will appreciate any advice or references to advice.  Also, exact part
>numbers/company names etc. for the relays will help!

Are you switching high level signals or low level signals like pre-amp
out level signals?  Also, are the clicks you mentioning the big
clack that happens when it switches or are you refering to contact
bounce?  How are you driving the relays?  TTL gate output?  Switching
transistor?  How are the relays connected to what you are driving?

Need more specifics to answer your question!! :-)

Newsgroup: sci.electronics
document_id: 53780
From: loving@lanai.cs.ucla.edu (Mike Loving)
Subject: specs on eprom data formats


I need the specs on various eprom data formats such as Intel Hex, Motorola S
JEDEC etc.


Can anyone out there provide such info or a pointer to it?
The one I want the most is Intel Hex.

Mike


Newsgroup: sci.electronics
document_id: 53781
From: payne@crl.dec.com (Andrew Payne)
Subject: WANTED:  TCM3105 chips, small quantities


Does anyone know if a source for the TCM3105 modem chips (as used in the
Baycom and my PMP modems)?  Ideally, something that is geared toward 
hobbyists:  small quantity, mail order, etc.

For years, we've been buying them from a distributor (Marshall) by the
hundreds for PMP kits.  But orders have dropped to the point where we can
no longer afford to offer this service.  And all of the distributors I've
checked have some crazy minimum order ($100, or so).

I'd like to find a source for those still interested in building PMP kits.
Any suggestions?

-- 
Andrew C. Payne
DEC Cambridge Research Lab

Newsgroup: sci.electronics
document_id: 53782
From: babb@rapnet.sanders.lockheed.com (Scott Babb)
Subject: Re: Radar detector DETECTORS?

Brian Day (bday@lambda.msfc.nasa.gov) wrote:
: On December 29, 1992, it was illegal to operate a radar detector
: in the state of Virginia.  If one got caught, one got fined $65.00.
: Ask me how I know.

The Federal Communications Act of 1934 made it *legal* for you to
operate a radio receiver of any kind, on any frequency (including
X, K, and Ka bands) in the United States.  The Electronic
Communications Privacy Act of 1989(?) restricted the FCA of 1934
by making it illegal to receive the land-mobile telephone service,
including (I believe) cellular phones.  No restriction was placed
on receiving RADAR (or, curiously, cordless phones.)  Enforcement
of the Virginia law is in violation of the FCA of 1934.  If you have
lots of time and money (and a lawyer, which I'm *not*,) you can
argue this in a federal court and try to have the law overturned.

I can hardly wait to see the responses to this one, but somebody
had to say it...

--
   Lockheed Sanders may disagree so these are solely the opinions of:
             Scott L. Babb - babb@rapnet.sanders.lockheed.com
              "We didn't inherit the Earth from our parents,
                   we are borrowing it from our children."

Newsgroup: sci.electronics
document_id: 53783
From: jhawk@panix.com (John Hawkinson)
Subject: Building a UV flashlight

Yes, I know it sounds crazy. Call it an urge. Call it what you want.
Just don't ask why :-)

Anyway, I'd like to build a UV flashlight, cheaply. "flashlight" means
it should be reasonably portable, but could have a power pack if
necessary.

My main question is the bulb: where can I get UV bulbs? Do they
need a lot of power? etc., etc.

I'm not too concerned with whether it's long-wave or short-wave
(but hey, if anyone has a cheap source of bulbs, I'll take both).

One other thing: a friend of mine mentioned something about near-UV
light being cheaper to get at than actual UV light. Does anyone
know what he was referring to?

Thanks much.


--
John Hawkinson
jhawk@panix.com

Newsgroup: sci.electronics
document_id: 53784
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: Circuit Cellar Ink address?

Is CCI still published?  If so, does anyone have their address?


Newsgroup: sci.electronics
document_id: 53785
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
>
>The Federal Communications Act of 1934 made it *legal* for you to
>operate a radio receiver of any kind, on any frequency (including
>X, K, and Ka bands) in the United States.  The Electronic
>Communications Privacy Act of 1989(?) restricted the FCA of 1934
>by making it illegal to receive the land-mobile telephone service,
>including (I believe) cellular phones.

Illegal to receive land-mobile telephone service?  Don't you have to have a
mobile reciever to even have land-mobile telephone service?  What about
ship-to-shore telephone service?

>No restriction was placed
>on receiving RADAR (or, curiously, cordless phones.)  Enforcement
>of the Virginia law is in violation of the FCA of 1934.

Isin't there some kind of rule (regulation, law, whatever) in some
juristictions that prohibit the use of *police band* recievers
in vehicles?  And that radar transmissions are included in the police band 
so they get covered by the same regulation?

Newsgroup: sci.electronics
document_id: 53786
From: Kirk_Cowen@panam.wimsey.bc.ca (Kirk Cowen)
Subject: references...

I've got the same problem; I can't dig up any info on the jumper settings
on the hd 3.5" drives.

Can anyone recommend a reference book(s) on the subject, rather than a
"quick fix" type answer??  I was going to start hooking up things and
logging the results, but the prospect of a ten second smoke test deters
me...

Thanks, Kirk Cowen.

-- Via DLG Pro v0.995


Newsgroup: sci.electronics
document_id: 53787
From: alung@megatest.com (Aaron Lung)
Subject: Re: Motorola XC68882RC33 and RC50

In article <C5qwv2.Bz0@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <sgberg.23xu@charon.bloomington.in.us> sgberg@charon.bloomington.in.us (Stefan Berg) writes:
>>... I don't know why my FPU has an XC (my original 33MHz FPU
>>was label MC68882-33), but it seems to work fine on my system...
>>P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)
>
>The rule for the designations is that if it says MC, that means it works
>*exactly* the way the datasheet/book specifies.  If it says XC, that means
>there is at least one known bug.  Often these bugs are small and obscure;
>you might never run into them in practice.
>

XC units are often pre-production sample devices.  Those are normally
distributed for evaluation as freebies and are not guaranteed to
meet every spec.

>At least Motorola admits it, unlike certain other companies...

Yep, that's for sure...that's one thing I like most about Motorola.

aaron

Newsgroup: sci.electronics
document_id: 53788
From: mont@netcom.com (Mont Pierce)
Subject: Re: 8051 Microcontroller

In article <1993Apr19.194525.3888@lambda.msfc.nasa.gov> bday@lambda.msfc.nasa.gov (Brian Day) writes:
>mcole@spock (COLE) writes:
>
>>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>>there know of any good FTP sites that might have compiliers, assemblers,  
>>etc.?
>
>Try lyman.pppl.gov -- /pub/8051

Great.  This site is a complete shadow of the Signetics BBS 8051 directory.

Thanks Brian,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53789
From: jmc@engr.engr.uark.edu (J. M. Carmack)
Subject: RE: Exploding TV

Just a thought........Maybe it possibly has to do with the fact that it
IS an Emerson.  I've got an Emerson VCR which is #6 in the series.  Returned
it six times for various and never the same problems.  Got tired of taking it 
back and fixed it myself.  The Hi-Fi "window" was a bit off.  Something like
the Hi-Fi audio fine-tuning.  When I was a Wal-Mart "associate" in '88-'89,
we had AT LEAST one returned as defective EVERY SINGLE DAY.  How's that for
reliability?  Face it--Emerson can make audio stuff (albeit not of premium
quality), but they CAN'T make anything as complex as video equipment with 
reliability IMHO.  Please, no flames.  Just *had* to share my Emerson disaster
in the light of this exploding tv.  
JC



-- 
-----------------+---------------+-------------+--------------+---------------
La Vie -- C'est Une Plage!  |  ?Caffine Not Present Error | jmc@engr.uark.edu
This Message Printed on     |  Abort, Retry, Fail ?       |
100% recycled electricity.  |                             |  Tangerine!!



Newsgroup: sci.electronics
document_id: 53790
From: Sean_Oliver@mindlink.bc.ca (Sean Oliver)
Subject: Re: Need to find out number to a phone line

> Joseph Mich Krzeszewsk writes:
>
> Msg-ID: <1quomg$f6m@bigboote.WPI.EDU>
> Posted: 19 Apr 1993 17:49:04 GMT
>
> Org.  : Worcester Polytechnic Institute
>
> Well, this is my second try at posting on this subject. Here goes...
>         In Texas (Corpus Christi at least) if you pick up the phone and
> dial
>         890 the phone company will read the number of the phone you are on
>         back to you. I believe the service department uses this to make
>         certain they are repairing the correct lines when they open the BIG
>         junction boxes. I don't know if it will work but you can give it a
>         try. Good luck.
>
>

Where I live, I use BCTEL. The number to dial is 211 for the same result.

--
+--------------------------------------------+
| Sean Oliver                                |
| Internet Address: a8647@MINDLINK.BC.CA     |
|                                            |
| Mindlink! BBS (604)576-1412                |
+--------------------------------------------+


Newsgroup: sci.electronics
document_id: 53791
From: mtrek@netcom.com (Chuck L. Peterson)
Subject: 40MHZ Oscilloscope FOR SALE

I'm giving up hardware design and
am selling my Oscilloscope:

	BK Precision  Model 1541B
	40 MHZ Dual-Trace
	Barely Used
	$450 firm   (Fry's sells it for $589+tax)

Prefer people in Silicon Valley, so I don't have to ship it.

mtrek@netcom.com

Newsgroup: sci.electronics
document_id: 53792
From: jdz1@Ra.MsState.Edu (John D. Zitterkopf)
Subject: Info: NEC70001AB Amp. IC & ~20W AMP secs & possible PSPICE models

Hi,

	Being a Electronic Engineering Student with only Electronic II under
my belt, I find myself *needing* to build a moderate wattage Audio Amp. So, 
I'll throw out a couple of question for the vast knowledge of the 'net'!

	Please Explain how Watts are calculated in Audio Amp circuits. No,
Not P=I*E, Just how it relates to one of the following:

	Ai [Current Gain]
	Av [Voltage Gain]
	Ap [Power Gain]
	or whatever.

I already have a ?wonderful? cheap I.E <$20 schematic for a 20W amp, but
I would like to Cross/improve the circuit. The problem is that the parts
list has IC1 and IC2 as NEC70001AB amplifiers. They look like ?11 pin? 
SIP packages with a heatsink. This schematic was published in a 1991 mag
so it may be non-existant now. Anyway, I tried looking up a replacement in
the latest Digi-key Cat and found it  not listed 8(. The closes I could
figure was a 9 pin SIP as TDA1520BU. Anyone got any Ideas? 

	I thought, hey I can rin a PSPICE simulation using 741 opamp 
models. Yea, great! It worked. But, I guess the 741 wasn't made for High
power amps. As a result, I got a Voltage gain of ~15mV/V. Worse than
I started with 8(... Does anyone have a PSPICE CKT file with cheap yet
good gain? How about some models for some of the chips listed in this 
E-mail? Any ASCII Chip info you guys can send me? 

I'm open to Suggestions/Ideas/Comments/Help!
Please E-mail since I have little time to search the News... 
And I'll post if there's and interest!
John


--
 ____________   _------_  |||IBM & |      EE majors Do it Best 8-)
  --------\\ ] ~-______-~ |||Atari |~~~~~~~~~John D. Zitterkopf~~~~~~~~~~~~~
     (~~~~~\\|_(__ ~~    / | \Rules!jdz1@ra.MsState.edu  jdz1@MsState.bitnet
      \______| (        /  |  \    |AOL: zitt@aol.com  jdz1@isis.MsState.edu 

Newsgroup: sci.electronics
document_id: 53793
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr20.022922.11861@julian.uwo.ca> wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
>>No restriction was placed
>>on receiving RADAR (or, curiously, cordless phones.)  Enforcement
>>of the Virginia law is in violation of the FCA of 1934.
>
>Isin't there some kind of rule (regulation, law, whatever) in some
>juristictions that prohibit the use of *police band* recievers
>in vehicles?  And that radar transmissions are included in the police band 
>so they get covered by the same regulation?

Those rules/regulations/laws would be subject to the same attack:  that
they are attempting to preempt federal authority to regulate (or not)
radio communications.  Of course, as the original poster noted, court
challenges of this kind can get expensive.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53794
From: randall@informix.com (Randall Rhea)
Subject: Re: Power, signal surges in home...

gstovall@crchh67.NoSubdomain.NoDomain (Greg Stovall) writes:
>Anyway, over the weekend, I was resting on the sofa (in between chores),
>and noticed that I briefly picked up what sounded like ham radio traffic
>over my stereo and television, even though both were off.  Also, all the
>touch sensitive lights in my house start going wacko, cycling through 
>their four brightness states.

>I presume that some ham operator with an illegal amplifier drove past
>my house (I live on a busy thoroughfare); would this be a correct presumption?
>What kind of power must he be putting out to cause the effects?  
>The affected equipment is about 100 feet from the road...

Hams can legally run up to 1500 watts.  It is very unlikely, however,
that a ham would be running that kind of power from a car.  Ham rigs
for cars put out around 100 watts.  It is possible that a 100 watt
radio would cause interference to consumer electronic 100 feet 
away.  Most TVs, stereos, and VCRs have very poor RF shielding.
If you experience the problem frequently, it may be 
caused by a ham, CBer, or other radio operator in a base station
nearby.    The interference may have been caused by a radio 
transmitter used for other purposes, such as police, fire,
etc.  If you heard voices over your stereo, I think you are
correct in assuming that the source is an RF transmitter.

If you have frequent trouble, you may want to try the RF ferrite
chokes available at Radio Shack.  The interference is probably
being picked up by your speaker wires, and those chokes can
be installed on the wires very easily (without cutting them).
Good instructions are included with the chokes.
If that does not solve the problem, you may want to search your
neighborhood for a radio operator.  Look for antennas on the roof
or car.  Talk to him/her about your problem.  There are things
a radio operator can do to reduce interference.

-- 

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Randall Rhea                                        Informix Software, Inc. 
Project Manager, MIS Sales/Marketing Systems    uunet!pyramid!infmx!randall

Newsgroup: sci.electronics
document_id: 53795
From: mg@cs.princeton.edu (Michael Golan)
Subject: how can 0.022 uF be different from two 0.047 in series?!

I was looking at the amps diagram for Sony 1090/2090 receivers, and I
was amazed to find a difference between the US and Canadian model
on the capacitor(s) that hangs off the output to the speakers:

                         ------\/\/\----- to speaker (identical both models
from amp ---------------|
(idnetical both models) >
                        <  10 
                        >
                        |
                       -----                        
                      |     |                        
        0.022        ---   ---        Canadian model only!
     US model        ---   --- 0.047 
     and world-wide   |     |
     model only.      |    ---        Candian model only!
                      |    ---  0.047
                      |     |
                       ----------- gound

The board itself is also identical, with room for all three caps. The
US/Can versions is clearly indicated in both places.

How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
(there are just standard caps, no special W/type/precision). 

Please explain this
 Michael Golan
 mg@cs.princeton.edu

Newsgroup: sci.electronics
document_id: 53796
From: buhrow@moria.nfbcal.org (Brian Buhrow)
Subject: NEED HELP FINDING DIP SWITCH SETTINGS AND JUMPER SETTINGS FOR 386SX MOTHERBOARD


Hello net.  I have a 386sx motherboard with the Phoenix BIOS, an on-board
IDE controller port, and two on-board serial ports.  Unfortunately, I don't
have a manual for this beast and I would like to be able to disable the IDE
controller in order to use the MFM controller I have.
The board says it is made in Korea and it uses the Chips Chipset.  If
anyone can give me a clue as to how to go about configuring the board so as
not to use the IDE controller, or how to go about finding out how to do it,
their help would be greatly appreciated.  
	Thank you in advance for your assistance.
Please mail buhrow@nfbcal.org with your responses as my news feed is rather
tenuous.
Thank you very much!
-Brian <buhrow@nfbcal.org>

Newsgroup: sci.electronics
document_id: 53797
From: randy@ve6bc.ampr.ab.ca (Randy J. Pointkoski)
Subject: Needed 24 volt 4 circuit Flasher


I am looking for a source for a 4 circuit Sequence flasher.

Input 24 Volts AC, 8 amps

Output: sequence to 4 channels (knob to vary frequency) (max 2 amps 
	per leg)
	Switch to put all channels on full time

Please Email any assistance you can provide.

Randy 			Email:  randy@ve6bc.ampr.ab.ca
-- 
   __
  /  )                                               Randy J Pointkoski P.Eng
 /    __________  _   __  _  _   _   o ________      Compression Technologies 
(__/ (_) / / / <_/_)_/ (_</_/_)_/_)_<_(_) / / <_     7141 77 ave

Newsgroup: sci.electronics
document_id: 53798
From: mgregory@flash.pax.tpa.com.au (Martin John Gregory)
Subject: HELP: MC146818A Real Time Clock Standby Mode


I am having trouble obtaining the specified standby current drain from
a MC146818A Real Time Clock.  Has anyone out there had some experience
in doing this?  The specs call for a few sequences to be met before
standby mode is activated, and are a bit hard to decipher on that, but
I thought that I had it worked out.  However, with a 32kHz crystal the
lowest current drain I can acheive at 3.7V Vcc is 150uA.  This is
three times the specified MAXIMUM under the conditions I am attempting
to create.

I have done the following things:

1) Made sure that RESET/ is asserted for Trlh after powerup, and AS is
   low during this time.


2) Made sure that there is a cycle on AS after the negation of RD/ or
   WR/ during which STBY/ was asserted.

What am I doing wrong?

Thanks very much,

Martin.

Newsgroup: sci.electronics
document_id: 53799
From: u934132@student.canberra.edu.au (Ogawa / Taro Stephen (ISE))
Subject: Help wanted

Could someone please tell me if a 1/4 decoder is the same as a 1 to 4
demultiplexer. I know how to link 2 of these to get an 8 output circuit,
but how do I link 5 of these to make a 1/16 multiplexer. Sorry if this
seems like a lame question, but I'm only a newbie to electronics, and I
have to do this circuit. Please make any mail as droolproof as possible.

				 Thanx,
					Taro Ogawa
					(u934132@student.canberra.edu.au)

Newsgroup: sci.electronics
document_id: 53800
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Dmm Advice Needed


|>   What the world needs is a meter that won't let you change ranges or
|> turn it on/off with a lead stuck in the amps jack - a little bit of
|> clever plastic detailing would take care of this and make the world
|> safer for electricans, anyway.
|>    Not that I've ever put a meter on the wrong range into a live 
|> circuit, no, not me...not more than a dozen times, anyway....
|>     Bill
|> 
|> 
|> bills@inqmind.bison.mb.ca
|> The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

The Fluke 87 beeps at you if you try to take it out of a current measuring
range while there is still a lead plugged in to the current sense socket.

... this should solve your problem - unless you are in a noisy environment.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53801
From: corwin@igc.apc.org (Corwin Nichols)
Subject: Re: Fujitsu 8" HDD


The Fujitsu 2322 uses what is known as an 'SMD' interface (Storage Module
Device?).  A lot of older minis used it.  Sun still does on their server
models.  There are several different speeds of SMD, and I think that the 
Fuji drive you have is rated at about 24 Mb/sec (thats megabits).  There
used to be several companies that made couplers for the PC (Interphase in
Texas being one), but I think that the market pretty much has dried up.
Controllers for this type of drive are readily available for VME buses
though.  Rumor has it that there is a SMD to SCSI adapter available, but
I think that it was designed for slower SMD devices.  In other words,
if you have a PC or Mac, that drive is pretty much dogmeat.
Cheers,
Corwin

Newsgroup: sci.electronics
document_id: 53802
From: ba1634807@ntuvax.ntu.ac.sg
Subject: pwm control thru software


currently I am using the 8051 microcontroller with external eprom..

In order to drive the dc motor (with direction) I use the Pulse width modultion 

thru software control(Assembly language programming). However I am afraid that

they will be overheads and thus alter the pulse timing. My question is 

is the software pwm control reliable?. I understand that port 0 is a latch

and so I vary the duty cycle by setting it high first and at the desire 

duty cycle then I set low..? Any improments ?
 

 

Newsgroup: sci.electronics
document_id: 53803
Subject: Re: Looking for Electronics Dept Info in Austrailia
From: MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham)

In <1993Apr19.003800.18288@worak.kaist.ac.kr> hjkim@hyowon.pusan.ac.kr writes:

> Hi Netters!
> 
> I am looking for the list of universities in Austrailia, which has electronics department. 
> I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
> But I don't have any information about Austrailian Universities.
> Can anybody recommend a good university in communication area?
> Any comments will be welcomed!
> 
> Bye.
> 
> Jaehyung Kim
> 
Well, I honestly don't know if they are good, bad or indifferent, but there
is an electronics dept here at La Trobe:
La Trobe University, Bundoora VIC 3083 Australia
Fax +613 471 0524
Chairman is Prof Ian White. Sorry, don't have an email address.
Graham B

Newsgroup: sci.electronics
document_id: 53804
From: NWZ96H@cheltenham-he.ac.uk (NWZ96H)
Subject: Hatley & Pirbhai help...

Hello,

Has anyone used the Requirements Analsys methodology Hatley & Pirbhai ? I am
a British final year real-time degree student, and as a project I am covering
this methodology. I would be very grateful to anyone who could give me their
views on this method. Please mail me if you feel you can help, and I will send
you my questions.

Thanks in advance,

David Phelps	(nwz96h@chelt.ac.uk)


Newsgroup: sci.electronics
document_id: 53805
From: dp@cec1.wustl.edu (David Prutchi)
Subject: OEM weight scale

Does someone sell OEM scale units with either analog or digital output?
I need something like the scales used in supermarket cash registers, 
with a dynamic range of a few pounds and reasonable accuracy.

Any sources ?        -David

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive           <prutchi@eng.tau.ac.il>     |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53806
From: d2bohre@dtek.chalmers.se (Henrik Bohre)
Subject: Digital Answering mach

Does anybody know anything about the chips D6275A/D6235A/D6205A chips from
DSP Telecommunications Inc?

I'd greatly appreciate information about price, pinouts and peripherals.

Regards,

  Henrik Bohre

  @>-+--

Newsgroup: sci.electronics
document_id: 53807
From: mvanhorn@desire.wright.edu (H.I.T. ( Hacker-In-Training ))
Subject: Re: Need to find out number to a phone

Since I have seen various different numbers to dial to get your number read
back to you by the phone company, could someonepost a list or point me to a
book where I could get a list of all the different numbers for the U.S.?
Failing that, could someone tell me Ohio's?


-- 
???????????????????????????????????????????????????????????????????????????????
?	451                             ?	I don't speak for Wright      ?
?  	mvanhorn@desire.wright.edu	?       State, I just give them       ?
?	Wright State University         ?       huge amounts of money.        ?
???????????????????????????????????????????????????????????????????????????????

Newsgroup: sci.electronics
document_id: 53808
From: keith@churchill.ColumbiaSC.NCR.COM (Keith.Boyd)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al
>
>  

Do you get a dial tone when you plug a phone into the jack??  If not,
then the line is possibly disconnected from the nearest telco junction
box. If you do get a dial tone, then surely the telco is sending a bill
for the line to *someplace* or *somebody*. Are you sure that what you
are doing is on the level. Sounds to me like you are just trying to get 
at somebody's unlisted number.  Fess up.

Keith


-- 
| Keith Boyd  (NCR- MCPD Cola.) |  Nothing could be finer than huntin' and   |
| 3325 Platt Springs Rd.        |    and fishin' in South Carolina! -Me-     | 
| West Cola., S.C. 29170 |   Go Gamecocks!   | keith.boyd@columbiasc.NCR.COM |
| Vp: 803-791-6419 or 6455    | From uunet: uunet!ncrcom!ncrcae!clodii!keith | 

Newsgroup: sci.electronics
document_id: 53809
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)

In article <1qg98sINNokf@sheoak.ucnv.edu.au> j. pethybridge,
jeff@redgum.ucnv.edu.au writes:
> I asked this a year ago, but i am still looking.
> I am getting sick of having to use a HC373 or a 8751/2.
Check out Xicor's new goodie in the April 12th edition of EETimes
X88C64 - an 8k * 8 E2PROM with built in latch AND bootloader setup.
You hook it directly to your '51, power it up, the prom initialises the
serial port on the '51, you load in your code via RXD, this gets blatted
onto the E2PROM, then you reset and run - i'm sure Dallas also does
something like this too, i suppose it would boil down to relative
prices, and the Dallas part freeing up P0 & P2 completely. I wonder
if ANYONE has ever managed to design a single sided PCB with an
8051, 573, EPROM, SRAM and >>NO LINKS<< ?
cheers
Mike.

Newsgroup: sci.electronics
document_id: 53810
From: fontana@cis.ohio-state.edu (Mark Fontana)
Subject: Homemade projector automation


Hi all,

I'm an assistant manager at a local art theater here in Columbus.  I'd
like to expand our show automation a bit- namely add the capability to
use cue tapes to bring the houselights up.  Our current automation
consoles date from the early 60's and don't provide this function.

We already have the combo failsafe/contact rollers to read the cuetapes,
and our dimmer system will raise the houselights when its fade-up control
circuit (120 VAC) is momentarily closed, for at least 0.5 second.

I've tried wiring the dimmer control to a 12V relay, activated when the
cue tape completes the circuit.  Low tech and simple, but there's one
problem:  In order to get the 1/2 second pulse, there needs to be
a sh**load of cuetape on the film.  (35mm runs at 90 feet per minute,
so to get a 1/2 second pulse, there needs to be at least 9 inches of solid
cuetape!)

Ideally, I would like to use a single cross-cue to accomplish this function.
(A single strip of cuetape perpendicular to the length of the film)
This would give a pulse of approximately 1/100 of a second.
What I need is a circuit to detect the short cue and activate the relay
for around 1/2 second.  The ability to adjust how long the relay
is activated would be nice.  I figure this would require an RC circuit
of some sort.  I'm sure some of you already have the solution figured
out in your heads.  Any suggestions and schematics would be appreciated!


Thanks,

Mark Fontana

-- 
 "Of all the arts, the cinema is  |  Mark A. Fontana
  the most important."            |  Computer and Information Science
                    --V.I. Lenin  |  THE Ohio State University

Newsgroup: sci.electronics
document_id: 53811
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Cicuit Cellar Ink - Extras 4 Trade

In article <babb-190493113153@larc.sdsu.edu> babb@sciences.sdsu.edu (J. Babb) writes:
>Fellow Info-junkies,
>  I have an extra CCI #27 (Real Time Programming/Embedded Sensors &
>Storage) and an extra CCI #32 (Voice control of telescope, among other
>articles). No labels. No torn, cut-up, or missing pages.
>
>Would like to trade for CCI # 26, or CCI # 23, or CCI # 19 in same
>condition (Labels OK).
>
>I mail mine you mail yours mutual trust kinda thang OK?
>You don't actually throw them away, do you?
>
>Thanx,
>Jeff Babb
>babb@sciences.sdsu.edu

I have also been trying to complete my collection.  I have an extra CCI # 16
(Communications) and a # 12 (Applications in the Arts), both in mint
condition.

I would like to trade for (or buy) the following: # 1, 3, 22, 23, 25, 26, 30,
and 31.

Thanks      -David

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53812
From: kng@pt.com (Ken Gravenstede)
Subject: Decent, CHEAP 20+MHZ Scopes?

Any info on modern 20MHZ or better dual trace scopes would be appreciated.
Should I buy a used one or a new one?  And where?

Please E-Mail.

Thanks in advance.

Ken
-- 
__
Ken Gravenstede, Performance Technologies Incorporated	kng@pt.com
315 Science Parkway, Rochester, New York 14620            uupsi!ptsys1!kng

Newsgroup: sci.electronics
document_id: 53813
From: cab@col.hp.com (Chris Best)
Subject: Re: Food Dehydrators

>   Does anybody out there have one of those food dehydrators I've been seeing
> all over late-night TV recently? I was wondering if they use forced air, heat,
> or both. If there's heat involved, anybody know what temperature they run at?
> My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
> and a heater. Seems to me you should be able to throw a dehydrator together
> for just a few bucks. Heck, the technology is only what? 1,000 years old?

----------

Yeah, but 1000 years ago, you couldn't buy it from a guy with sprayed-on hair!

Newsgroup: sci.electronics
document_id: 53814
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In <1993Apr19.185326.9830@Princeton.EDU> mg@cs.princeton.edu (Michael Golan) writes:

>I was looking at the amps diagram for Sony 1090/2090 receivers, and I
>was amazed to find a difference between the US and Canadian model
>on the capacitor(s) that hangs off the output to the speakers:

>                         ------\/\/\----- to speaker (identical both models
>from amp ---------------|
>(idnetical both models) >
>                        <  10 
>                        >
>                        |
>                       -----                        
>                      |     |                        
>        0.022        ---   ---        Canadian model only!
>     US model        ---   --- 0.047 
>     and world-wide   |     |
>     model only.      |    ---        Candian model only!
>                      |    ---  0.047
>                      |     |
>                       ----------- gound

>The board itself is also identical, with room for all three caps. The
>US/Can versions is clearly indicated in both places.

>How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
>(there are just standard caps, no special W/type/precision). 

>Please explain this
> Michael Golan
> mg@cs.princeton.edu

The only explanation I can think of is that two capacitors in series
can handle twice the output voltage. Sometimes two elco's in antiseries
(you know, positive sides facing eachother) are used to obtain a large
capacitor that can handle positive and negative voltages as well.

So there probably is no design-philosophical reason, but a production-cost
one.

Best 73's

Wouter

Newsgroup: sci.electronics
document_id: 53815
Subject: 68HC16 public domain software?
From: murashiea@mail.beckman.com (Ed Murashie)

Does anyone know of an FTP site where I might find public
domain software for the Motorola 68HC16 microprocessor?
I am looking for a basic interpreter/compilier or a 'C'
compiler.  Thanks in advance.
					Ed Murashie

------------------
Ed Murashie                     US Mail :  Beckman Instruments Inc.
phone: (714) 993-8895                      Diagnostic System Group 
fax:   (714) 961-3759                      200 S. Kraemer Blvd  W-361
Internet: murashiea@mail.beckman.com       Brea, Ca 92621  

Newsgroup: sci.electronics
document_id: 53816
From: aj008@cleveland.Freenet.Edu (Aaron M. Barnes)
Subject: Realistic PRO-2024 scanner for sale:was $200, sell for $150




Article 10886 of alt.radio.scanner:
Path: usenet.ins.cwru.edu!cleveland.Freenet.Edu!aj008
From: aj008@cleveland.Freenet.Edu (Aaron M. Barnes)
>Newsgroups: alt.radio.scanner
Subject: Realistic PRO-2024 for sale-was $200,sell for $150 obo
Date: 20 Apr 1993 16:01:28 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
Lines: 26
Message-ID: <1r16oo$3du@usenet.INS.CWRU.Edu>
NNTP-Posting-Host: slc10.ins.cwru.edu


Hello.

I have a Realistic PRO-2024 scanner for sale.Here is a small desc
ription:

60 programible chanels
fully detailed backlighted digital display
headphone jack
antenna jack
removable telescoping antenna
auto search

coverage:
30-50mHz
118-174mHz
380-512mHz

It originally cost $200, but I will sell for $150.

Thank You.
-- 
       / /     Buchanan in `96!
      / /      Fear the goverment that fears your guns.
  \ \/ /       Without the 2nd amendment, we cannot guarantee ou
   \/ /        r freedoms.           aj008@cleveland.freenet.edu
-- 
       / /     Buchanan in `96!
      / /      Fear the goverment that fears your guns.
  \ \/ /       Without the 2nd amendment, we cannot guarantee ou
   \/ /        r freedoms.           aj008@cleveland.freenet.edu

Newsgroup: sci.electronics
document_id: 53817
From: johnr@col.hp.com (John T. Rasper)
Subject: ADCOM GTP500II IR sensor & repeater spec's?

Does anyone know the details of the interface (5 wire din) for the
IR remote sensor & (2 wire IR repeater) for the ADCOM GTP-500II
preamp?  The ADCOM part numbers are the XR-500II, SPM-500II, and 
IRA-500II.

A cursory physical examination of the pre-amp connector indicates
that the connector (5 pin din) may provide: (Viewed from connector front)

      |
   5     1     (pin ?) +?v @ ???mA
    4   2      (pin ?) +/-?v @ ???mA
      3        (pin 3) Signal Ground
               (pin ?) Demodulated signal ?V-pp, ? polarity, ? mA drive
               (pin ?) Signal to drive repeater LED (drives through 150ohm
                       resistor) ?V-pp

I assume that the repeater connectors (mini-plugs) drive the IR repeater
LED's directly.  True?

Can anyone fill in the ?'s.  Thanks.

--
John Rasper                         Hewlett-Packard COL
johnr@col.hp.com                    P.O. Box 2197
(719) 590-5895                      Colorado Springs, CO 80901-2197

Newsgroup: sci.electronics
document_id: 53818
From: moffatt@bnr.ca (John Thomson)
Subject: Re: What is Zero dB????

marrevola@rediris.es wrote:
: In article <1993Apr6.132429.16154@bnr.ca>, moffatt@bnr.ca (John Thomson) writes:
: > Joseph Chiu (josephc@cco.caltech.edu) wrote:
: > 
: > : And the measure of current, Amp, is actually named after both the AMP company
: > : and the Amphenol company.  Both companies revolutionized electronics by
: > : simulatenously realizing that the performance of connectors and sockets 
: > : were affected by the amount of current running through the wires.
: > 
: > Sorry.  The unit for current is the AMPERE which is the name of a french-man
: > named AMPERE who studied electrical current.  The term AMP is just an abbreviation
: > of it.  The company AMP came after the AMPERE unit was already in use.
: >   
: > : The Ohmite company was the first to characterize resistances by numbers, thus
: > : our use of the Ohms...
: > 
: > I don't know about this one, but it doesn't sound right.
: Are you (two) joking?
: Is the entire Internet flaming you (two)?
: Ahh!, now I remember that Ohmite company was the first introducing "the pink
: colored resistor", only for electronics working females ;-)
: -- 
: Manuel Arrevola Velasco   ||||| True e-mail: manolo@taf.fundesco.es |||||
: DoD #1033
: 
Yes, I have taken a bit of flame on this one.  I must've been half asleep when
I posted a response to Joseph.

Greggo.
-----
Greg Moffatt  moffatt@bnr.ca
Bell-Northern Research Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
document_id: 53819
From: philip@mentorg.com (Philip Peake)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr20.022922.11861@julian.uwo.ca>, wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
|> In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
|> 
|> >No restriction was placed
|> >on receiving RADAR (or, curiously, cordless phones.)  Enforcement
|> >of the Virginia law is in violation of the FCA of 1934.
|> 
|> Isin't there some kind of rule (regulation, law, whatever) in some
|> juristictions that prohibit the use of *police band* recievers
|> in vehicles?  And that radar transmissions are included in the police band 
|> so they get covered by the same regulation?

What do you mean by "police band" - there is no such thing.

Anyway, radar detectors work in shared bands.
If you applied your test, all of those radar operated door
openers in malls would be illegal.

One of the great problems here is that there are too many
ill-educated (read illiterate) people making too many laws
about subjects on which they are incompetent - there may well
be laws refereing to "police bands", they are almost certainly
local in scope (state or county) - created by well-meaning,
but incompetent idiots.

Unfortunaltely, laws do not have to be sensible (or even enforceable).
Lawmakers exist to pass laws - and will continue to do so, until
the day where you are faced with death for not doing X, and
amputation of all your limbs for doing X ... the choice will be yours.

Note: no smiley.

Philip

Newsgroup: sci.electronics
document_id: 53820
From: dclaar@cup.hp.com (Doug Claar)
Subject: Los Angeles Freeway traffic reports

While driving through the middle of nowhere, I picked up KNBR, AM 1070,
a clear-channel station based in Los Angeles. They had an ad 
claiming that they were able to get traffic flow information from 
all of the thousands of traffic sensors that CalTrans has placed
under the pavement. Does CalTrans sell this info? Does KNBR have
an exclusive? What's the deal?

==Doug "Former L.A. commuter" Claar

Newsgroup: sci.electronics
document_id: 53821
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Suggestions  on Audio relays ???

In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>I built a little project using the radio shack 5vdc relays to switch
>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>most of the common things one is supposed to do when using relays and
>>nothing seemed to get rid of the clicks.
>>
>>
>>My question is:
>>
>>	Is there a good relay/relay circuit that I can use for switching
>>audio, so that there will be *NO* noise of any kind on the audio lines.
>>
>>
>>I will appreciate any advice or references to advice.  Also, exact part
>>numbers/company names etc. for the relays will help!
> 
> Are you switching high level signals or low level signals like pre-amp
> out level signals?  Also, are the clicks you mentioning the big
> clack that happens when it switches or are you refering to contact
> bounce?  How are you driving the relays?  TTL gate output?  Switching
> transistor?  How are the relays connected to what you are driving?
> 
> Need more specifics to answer your question!! :-)

As a general rule, no relay will cleanly switch audio if you try to tranfer
the circuit with the contacts.  The noise you hear is due to the momentary
opening and closing of the path.

The noiseless way of transfering audio is to ground the circuit.  In high
impedance audio circuits a resistive "T" is constructed close to characteristic
impedance of the circuit.  Grounding the imputs (connected to the T) transfers
the audio.

In low impedance circuits transformers are usually used, and the inputs are
shorted out or grounded.  Secondaries are paralleled at the characteristic
impedance.

Sometimes if it is necessary to actually switch audio, a second contact is used
to momentarily short the circuit output for the duration of the switching time.

Telephone relays are handy, because contacts can be adjusted to "Make before
break and Vica Versa" but I haven't seen any of these for years.

Nowadys switching is done electronically with OP amps, etc.

A novel circuit I used to build was a primitive "optical isolator".. It consists
of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
off the cell is high resistance.  Turn the lamp on and the resistance lowers
passing the audio.  Once again this device in a "T" switches the audio.  Varying
the lamp resistance give a remote volume control.  Use 2 variable resisters and
you have a mixer!

Lots of luck!
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
document_id: 53822
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: correction of last followup re relays

In article <1993Apr20.102756.1709@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
> In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
>> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>>I built a little project using the radio shack 5vdc relays to switch
>>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>>most of the common things one is supposed to do when using relays and
>>>nothing seemed to get rid of the clicks.
>>>
>>>
>>>My question is:
>>>
>>>	Is there a good relay/relay circuit that I can use for switching
>>>audio, so that there will be *NO* noise of any kind on the audio lines.
>>>
>>>
>>>I will appreciate any advice or references to advice.  Also, exact part
>>>numbers/company names etc. for the relays will help!
>> 
>> Are you switching high level signals or low level signals like pre-amp
>> out level signals?  Also, are the clicks you mentioning the big
>> clack that happens when it switches or are you refering to contact
>> bounce?  How are you driving the relays?  TTL gate output?  Switching
>> transistor?  How are the relays connected to what you are driving?
>> 
>> Need more specifics to answer your question!! :-)
> 
> As a general rule, no relay will cleanly switch audio if you try to tranfer
> the circuit with the contacts.  The noise you hear is due to the momentary
> opening and closing of the path.
> 
> The noiseless way of transfering audio is to ground the circuit.  In high
> impedance audio circuits a resistive "T" is constructed close to characteristic
> impedance of the circuit.  Grounding the imputs (connected to the T) transfers
> the audio.
> 
> In low impedance circuits transformers are usually used, and the inputs are
> shorted out or grounded.  Secondaries are paralleled at the characteristic
> impedance.
> 
> Sometimes if it is necessary to actually switch audio, a second contact is used
> to momentarily short the circuit output for the duration of the switching time.
> 
> Telephone relays are handy, because contacts can be adjusted to "Make before
> break and Vica Versa" but I haven't seen any of these for years.
> 
> Nowadys switching is done electronically with OP amps, etc.
> 
> A novel circuit I used to build was a primitive "optical isolator".. It consists
> of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
> off the cell is high resistance.  Turn the lamp on and the resistance lowers
> passing the audio.  Once again this device in a "T" switches the audio.  Varying
> the lamp resistance give a remote volume control.  Use 2 variable resisters and
> you have a mixer!
> 
> Lots of luck!
> -- 
> 73, Tom
> ================================================================================
> Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
> (604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
> Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  
> 
> I do not recyle.....   I keep everything!       (All standard disclaimers apply)
> ================================================================================
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
document_id: 53823
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: correction re Audio relay followup

Gremilins have attacked my keyboard and the correction to my followup on audio
relays got fouled up.  
Varying lamp resistance, should read, "Varying lamp voltage"
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
document_id: 53824
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Building a UV flashlight

You can get a *little* UV by putting a heavy UV filter (deep purple) in
front of an ordinary flashlight bulb (the brightest you can get).
My father used a setup like this in law enforcement work circa 1964.

Good UV ("blacklight") bulbs work like fluorescent bulbs.  I'd proceed by
getting a cheap battery-powered _fluorescent_ light, then going to an
electrical supply house and finding a UV bulb that would fit it.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53825
From: kehoe@netcom.com (Thomas David Kehoe)
Subject: Re: Telephone Controlled Power Bar Needed


I had a similar idea, for a fax/answering machine switch,
to put both machines on one line.  You order distinctive
ringing from your phone company.  This is $3/month here.
You get a second (unpublished) phone number.  When
someone calls this number, your phone rings with short
rings instead of long rings.

You set up your answering machine on 4 rings and your fax
on six rings.  You'd give out the new # as your fax #.
A device would measure the length of rings.  When it
detects a short ring, it turns off your answering machine.
Five rings later your fax picks up the call.

This should be cheaper and more elegant than the $80
switches now available.

But that's not what I did.  I'm giving out the new
# to my friends and customers.  This should leave the
old # for telemarketers, etc.  I won't pick up the
phone when I hear the long rings.
-- 
"Why my thoughts are my own, when they are in, but when they are out
they are another's." - Susannah Martin, hanged for witchcraft, 1692.
Thomas David Kehoe          kehoe@netcom.com         (408) 354-5926

Newsgroup: sci.electronics
document_id: 53826
From: <PCA103@psuvm.psu.edu>
Subject: ATARI 2600 Processors

Does anyone know what processor the Atari 2600 used? What I'm looking for is th
e pin-outs for the Atari 2600.... the schematics for it it... does anyone have
any idea where I could find this or any related information? This is very impor
tant. Also, are the ROM chips that were used fo rthe 2600 games still available
, or were they propreitary? Please email me with any responces, as this is very
 important.. Thanks a million...

BTW- Anyone who works/has worked for Atari, I could really use your help with i
nfo on the old 2600, please email me if you are willing to help me.... thatnks
alot!!

-Peter

Newsgroup: sci.electronics
document_id: 53827
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dmm Advice Needed

I've had my Fluke 8060A here at work for just over 10 years now.
It is a wonderful meter.  Several colleagues here have some of the
newer Fluke meters, though I still would just as soon hang on to my
8060.  The 8060 a is the 1980s digial "analog" to the Simpson 260
analog DMM of the 1950-1960s.  There was/is (?) an 8060B that had
extended frequency response.

I've got a nifty little pen shaped meter made by Soar that I keep
in my toolbox at home.  I've had that for six or seven years now
and only replaced the batteries a couple of timees; it is more than
adequate for day-to-day hobby use.  I think Soar OEMs their stuff
for a number of vendors.  Some of JDR Microdevices' stuff looks
rather similar to Soar's.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53828
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: help: How to reduce the RPMs of a Boxer fan ?

Yes, you increase the RPM slip of a "boxer" type fan by installing
a capacitor in series with the fan's power supply.  The air flow of
small 3.5 inch fans can be reduced by about 50% by using a 1 to 4
uF capacitor.  Use a good grade nonpolarized unit with working
voltage rating around 250 volts.  Note that some impriical study is
usually required to experimentally determine the best size
capacitor for a given application.

For DC powered applications, try the Radio Shack 12 volt box fan.
It can run and start reliably from as low as about 4.5 VDC.  It is
exceptionally quiet, but at admittedly low flow.  I wish I knew who
made the fans for Radio Shack.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53829
From: cantrell@sauron.msfc.nasa.gov (Eric Cantrell)
Subject: EEG Kit?

Awhile back someone posted some information on where you can get
kits to build an EEG.  Does anyone remember where you could get
this.  I'm very interested in getting some info on this.  Thanks 
in advance.

eric

cantrell@sauron.msfc.nasa      


Newsgroup: sci.electronics
document_id: 53830
From: coyne@thing1.cc.utexas.edu ()
Subject: Re: Radar detector DETECTORS?

It is illegal to use anything you eavedropped on for a business 
or for an illegal use.  Jurisdictions that ban radar detectors or
police monitors, are essentially making the claim that there is no
other reason for a radar detector or police radio monitor. 

The results of fighting these claims in courts have been mixed.
The federal courts are not anxious to intervene and state courts
have sometimes held that the feds have exclusive jurisdiction
and sometimes they have not.  A lot of state courts do not have
enough imagination to see any use for a radar detector besides
avoiding law enforcement action for speeding.

When you buy a radar detector, amongst the guarrantees, instructions, 
explanations, and other detritus, is an invitation to join an
association dedicated to preserving your right to use a radar detector.
(I promise I am not making this up!)

I do not think radar detector manufacturers would be making any 
headway at all in courtrooms if police departments enforced speed 
laws with a strict eye to public safety and a blind eye to the fund
raiser aspect of tickets.  

Mike Coyne


Newsgroup: sci.electronics
document_id: 53831
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dayton Hamfest

Yes,

Take Interstate I-70 to the route 48 exit.  Go south on 48 about
2-1/2 miles.  Trun right on Shiloh Springs Road.  The hamvention is
at the Harrah arena, which is about 1 mile west and on the north
side of the Road.  Parking at the arena is limited.  Lodging is
probably entirely booked-up within a 40 mile radius.  Good luck.

                |                |
                48               I75
                |                |
----------I70----------....---------
                |                |
                |                |
          X     |                |
(mall)  --------|                |
   S. Springs   |

It is possible to park at the mall to the west.  There are shuttle
busses running between the arena and the mall.

If possible, get a Montgomery County, OH map from your local AAA
office.  It should be free if you are an AAA member.

If you don't already have definite plans, now is not a particularly
good time to start to think about going to the hamvention.



-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53832
From: verity@jack.sns.com (Steve Verity)
Subject: Need help with video detection circuit



I am trying to build a circuit that detects the presence of video (Vs.
a blank screen) by monitoring the R,G, and B outputs of a graphics
card.  It should be able to detect the presence of a single pixel at
65 MHz, which would mean detecting a 15 NS pulse.  It should also be
able to tell the difference between a blank screen (about 300 mv)
and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
cheap.  

My first circuit was a dismal failure.  I used 3 compariators; each
compariator had the + input going to one of the guns, the - input
went to a reference created by a voltage divider(a potentiometer).

The first problem was that the compariator was way too slow.. I
needed to get several pixels in a row before it would fire the
compariators, so I could have a whole screen full of text, but my
circuit would not detect it.   

The second problem is that there was more noise on the reference then
the smallest difference between a blank screen and a dim screen.  In
fact the difference between completely black and completely white is
only 650 mv.  I am wondering if I am going to have to amplify the
video signals to make this work.  

There are faster compariators, but they are expensive, and require 
split supplies.   I would need to replace my .49 quad compariator
with three 1.89 compariators, and create a whole new power supply
circuit.  

At this point, I think what I need is some sort of transistor
circuit.  Transistors are fast and cheap and should do the trick...

Unfortunately, I am way out of my league when It comes to designing
transistor circuits, so I am appealing to the net for help.  Any
ideas, tips, circuits, pointers, references, etc. would be greatly
appreciated.  

Oh yes, I only sample the output of this thing every second or so, so
I don't need a fast response time at all, however, I haven't found a
way to take advantage of that fact.

Thanks a lot for any help anybody might be able to give. Of course,
you will have my undying gratitude.


Steve Verity




-- 
..........>.........>........>......>...>...>..>..>..>..>.>.>.>>>>>>>>+ .   
Steve Verity                  +   +             ...Maxed on MIDI        + .
                                    +      verity@jack.sns.com      + ..   +

Newsgroup: sci.electronics
document_id: 53833
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Long distance IR detection


--

I would like to be able to detect the angular position (low accuracy) of an
IR emitting source at a distance of about 100 meters (more is better) in
daylight.  The IR source could be emitting a signature; I'm leaning toward
30 KHz square wave with 50% duty cycle.

I am considering the use of a quadrant detector from Centronic Inc. to give
information to a pan/tilt head to point the sensor and thus determine the
angles.  For the source I am considering wazing the heck out of an IR LED(s),
possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
current pulses.  At this current the duty cycle of the LED drops to 10% and I
would need to cycle five of them in turn to get the 50% required.

Has anyone done something like this?

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
document_id: 53834
From: drand@spinner.osf.org (Douglas S. Rand)
Subject: Re: Power, signal surges in home...

In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:

   gstovall@crchh67.NoSubdomain.NoDomain (Greg Stovall) writes:
   >Anyway, over the weekend, I was resting on the sofa (in between chores),
   >and noticed that I briefly picked up what sounded like ham radio traffic
   >over my stereo and television, even though both were off.  Also, all the
   >touch sensitive lights in my house start going wacko, cycling through 
   >their four brightness states.

   >I presume that some ham operator with an illegal amplifier drove past
   >my house (I live on a busy thoroughfare); would this be a correct presumption?
   >What kind of power must he be putting out to cause the effects?  
   >The affected equipment is about 100 feet from the road...

Hams are unlikely to have an illegal amp,  and are also unlikely to
have a "dirty" amp.

   Hams can legally run up to 1500 watts.  It is very unlikely, however,
   that a ham would be running that kind of power from a car.  Ham rigs

Not possible either.  You'd need about a 300 amp alternator for
just the amplifier.  I can just see it.  You need to slow
down on a downgrade,  so you hit the push to talk button.

   for cars put out around 100 watts.  It is possible that a 100 watt
   radio would cause interference to consumer electronic 100 feet 
   away.  Most TVs, stereos, and VCRs have very poor RF shielding.
   If you experience the problem frequently, it may be 
   caused by a ham, CBer, or other radio operator in a base station
   nearby.    The interference may have been caused by a radio 
   transmitter used for other purposes, such as police, fire,
   etc.  If you heard voices over your stereo, I think you are
   correct in assuming that the source is an RF transmitter.

   If you have frequent trouble, you may want to try the RF ferrite
   chokes available at Radio Shack.  The interference is probably
   being picked up by your speaker wires, and those chokes can
   be installed on the wires very easily (without cutting them).
   Good instructions are included with the chokes.
   If that does not solve the problem, you may want to search your
   neighborhood for a radio operator.  Look for antennas on the roof
   or car.  Talk to him/her about your problem.  There are things
   a radio operator can do to reduce interference.

And please remember to be friendly when approaching your
local radio operator.  This person may or may not be the 
cause of your troubles,  and you'll get better cooperation
and help if you assume that he is going to be helpful (most
are).  It was amazing the accusations that we sometimes
dealt with as I grew up.  We were blamed for skip (ghost
pictures on the TV that occur at sunspot peaks),  c.b.
interferance,  dead grass :),  you name it.  

BTW, the local operator should try and help you whether or
not he or she is directly responsible.  It is part of
being a good neighbor and that is how the FCC views it.
Too bad they don't require the consumer equipment makers
to take any precautions.

Last, you can usually tell ham radio vs. CB.  Ham operators are
required to declare their call (sign) every so many minutes (no more
than 10).  So if you hear "This is WA1QT" or some other call starting
with A, W or K and no more than 6 total characters, you heard a ham.
CB'ers probably won't sign (I don't know that they're even required
to) and fire/police have other private ids.






--
Douglas S. Rand <drand@osf.org>		OSF/Motif Dev.
Snail:         11 Cambridge Center,  Cambridge,  MA  02142
Disclaimer:    I don't know if OSF agrees with me... let's vote on it.
Amateur Radio: KC1KJ

Newsgroup: sci.electronics
document_id: 53835
From: hl00@ns1.cc.lehigh.edu (HOU-SHENG LIN)
Subject: Laser vs Bubblejet?

Well, I'm not too sure if this would be the right place to post this, but
anyway, here goes:  I was just noticing that some of the current bubblejet
printers offers up to 360x360 resolution while a lot of lower end laser
printers only offer 300x300.  However, the laser printers still seems to be
significantly pricier than the bubblejets... how is this?  Or am I missing
something about the resolution thing?

-- 
-Sheng
hl00@pl122.eecs.lehigh.edu
hl00@m180k.cc.lehigh.edu
hl00@lehigh.edu

Newsgroup: sci.electronics
document_id: 53836
From: monta@image.mit.edu (Peter Monta)
Subject: Re: MC SBI mixer

musone@acsu.buffalo.edu (Mark J. Musone) writes:

> P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
> ELECTRICAL DIAGRAMS would help a lot.
> I have seen a lot of theory books with no circuits and a lot of
> circuit books with no theory, but one without the other does not help.

Mixers have a wide variety of implementations; the Mini-Circuits
part you mention is a doubly-balanced diode mixer, but active ones
(BJT, FET) seem more popular in consumer receivers.  You might
call MCL; they have a nice catalog.

The universal answer for wide-coverage, theory+practice, RF design
is the _ARRL Handbook_, published by the American Radio Relay
League, the radio amateur organization.  Any technical bookstore
can order you one.  The book is superb, with lots of accessible
theory, construction projects, and generally interesting stuff.

You might also check out _Solid State Design for the Radio Amateur_
(I think), by Hayward and <someone>.  This has sharper design
and test information about subsystems like mixers.

Peter Monta   monta@image.mit.edu
MIT Advanced Television Research Program

Newsgroup: sci.electronics
document_id: 53837
From: geva@concave.cs.wits.ac.za (Geva Patz)
Subject: How do I make me own really-short-run CD's

I want to be able to take a bunch of home-made songs (from DAT or other 
suitable master) and output them to a short run (10-20 off) of standard 
music CDs. Would one of the CD recorders designed for writeable CD ROMs work 
for this purpose? Alternatively, is there a service that does this sort of 
thing for a fee? 

I'm after as much information as possible on the alternatives (cost, lead 
time, equipment required, procedure to follow, etc.)  Email replies would be 
appreciated.

%%%%     Geva Patz
 Geva    Department of Computer Science, WITS University
  %%%%   geva@concave.cs.wits.ac.za

Newsgroup: sci.electronics
document_id: 53838
From: sehari@iastate.edu (Babak Sehari)
Subject: How to the disks copy protected.

---

I was wondering, what copy protection techniques are avaliable, and how
effective are they?  Has anyone have any experience in this area?

                      With highest regards,
                           Babak   Sehari.


-- 

Newsgroup: sci.electronics
document_id: 53839
From: jung@rz.tu-ilmenau.de (Dirk Junghanns)
Subject: W86C451, W86C456 info wanted

Does anybody have informations about the

 W 86 C 451   and  W 86 C 456 chips (40pin DIL pckg)?

They are build in a multifunction io-card for pc.

Thanks 
         Dirk
-- 
------------------------------------------------------------
Dirk Junghanns                    junghanns@rz.tu-ilmenau.de
------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53840
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Power, signal surges in home...

drand@spinner.osf.org (Douglas S. Rand) writes:

>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>   that a ham would be running that kind of power from a car.
>
>Not possible either.  You'd need about a 300 amp alternator for
>just the amplifier.

It is too possible.  As the original poster said "it is very unlikely"
but definately possible.  (Can you say batteries?)

Newsgroup: sci.electronics
document_id: 53841
From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
Subject: PADS Question - How do I go from a schematic -> PCB?

After I have produced a schematic with PADS-LOGIC, how do I import it into 
PADS-PCB to create a PCB pattern?  The only way I've gotten it to work is
to output a FutureNet netlist, and then import this into PADS-PCB.  Is there
another way of doing this?  I didn't see any information in the instructions
provided, but I might have missed something.  Any suggestions would be 
greatly appreciated.  Thanks!


 _I_______________________________________________________________________I_
(_@_)                                                                   (_@_)
|   |   Raymond Yeung               Internet: Nimbus@uiuc.edu           |   |
|   |                                         rky57514@uxa.cso.uiuc.edu |   |
|   |   EE student at the                                               |   |
|   |   University of Illinois    CompuServe: 70700,1011                |   |
|   |   at Urbana-Champaign                                             |   |
(___)-------------------------------------------------------------------(___)
  I                                                                       I

Newsgroup: sci.electronics
document_id: 53842
From: ianchan@leland.Stanford.EDU (Ian Hin Yun Chan)
Subject: Need help on...

I need help on 4 components:

BAT85 diode
-----------
I know Digi-key or Newark sells them, but the minimum order is 25!
Does anyone know where I can get smaller orders of this diode, or
an equivalent replacement?

BC546B transistor
-----------------
Ditto for this transistor.

74HC239 chip
------------
Digi-key, Newark and Mouser do not appear to carry ths chip - does anyone
know what this does and where I can obtain it?

YM3623B chip
------------
This Yamaha chip decodes S/PDIF data (from CD or DAT). Where can I obtain
one of these?

Thanks in advance,
- Ian

Newsgroup: sci.electronics
document_id: 53843
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr20.173742.99726@ns1.cc.lehigh.edu> hl00@ns1.cc.lehigh.edu (HOU-SHENG LIN) writes:
>Well, I'm not too sure if this would be the right place to post this, but
>anyway, here goes:  I was just noticing that some of the current bubblejet
>printers offers up to 360x360 resolution while a lot of lower end laser
>printers only offer 300x300.  However, the laser printers still seems to be
>significantly pricier than the bubblejets... how is this?  Or am I missing
>something about the resolution thing?

Bubblejets often splatter a little bit, whereas LaserJets (given half-way decent
toner, like HP's "Microfine" stuff) don't.  Both produce very good output,
but you don't have to look too closely at the two to tell that LaserJet
output is definitely superior.  

On the other hand, LaserJets which haven't been maintained properly and use
the cheapest toner the owner could find often produce awful output, much
worse than a bubblejet. :-)

One other thing... there are bubblejets, and then there are BubbleJets.
There are a few bubblejets out there that produce rather mediocre output
(such as HP's dinky little BubbleJet), whereas most produce really good
looking output (such as HP's DeskJets).  IBM and Canon both produce some of
the really good style bubblejets.

					---Joel Kolstad

P.S. -- If you're in the market for a portable bublejet printer, I can
highly recommend the HP Portable DeskJet, although I've heard the portable
Canons are good too (I needed PCL support, myself).  With the DeskJet
Portable, you even get an undocumented PCMCIA card slot!

Newsgroup: sci.electronics
document_id: 53844
From: ravin@eecg.toronto.edu (Govindan Ravindran)
Subject: decoupling caps - onboard

(posted for a friend)
hello there,
        I would like to know if any one had any experience with having
on-board decoupling capacitors (inside a cmos chip) for the power
lines. Say I have a lot of space left im my pad limited design.
any data on the effect of oxide breakdown? any info or pointers
are appreciated.

rs


Newsgroup: sci.electronics
document_id: 53845
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: EEG Kit?

In article <cantrell.735330560@sauron.msfc.nasa.gov> cantrell@sauron.msfc.nasa.gov (Eric Cantrell) writes:
>Awhile back someone posted some information on where you can get
>kits to build an EEG.  Does anyone remember where you could get
>this.  I'm very interested in getting some info on this.  Thanks 
>in advance.
>
>eric
>
>cantrell@sauron.msfc.nasa      
>

Contact Circuit Cellar Inc., 4 Park St. - Suite 12, Vernon, CT 06066
(203)875-2751, FAX (203)872-2204 and inquire about HAL-4 EEG Biofeedback
Brainwave Analyzer.  

In addition, if you want to build your own system from board-level compo-
nents (biosignal amplifiers, analog isolators and isolated multiplexers)
you can contact The Davron Group,P.O. Box 237, Deerfield, IL  60015
FAX (708)948-9290.

- David


+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53846
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Long distance IR detection

In article <1993Apr20.183416.18744@dres.dnd.ca> sburton@dres.dnd.ca (Stan Burton) writes:
>
>--
>
>I would like to be able to detect the angular position (low accuracy) of an
>IR emitting source at a distance of about 100 meters (more is better) in
>daylight.  The IR source could be emitting a signature; I'm leaning toward
>30 KHz square wave with 50% duty cycle.
>
>I am considering the use of a quadrant detector from Centronic Inc. to give
>information to a pan/tilt head to point the sensor and thus determine the
>angles.  For the source I am considering wazing the heck out of an IR LED(s),
>possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
>current pulses.  At this current the duty cycle of the LED drops to 10% and I
>would need to cycle five of them in turn to get the 50% required.
>
>Has anyone done something like this?
>
>Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
>(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

A method which will directly (almost) provide you with the information that
you require is that which is commonly used for coordinate measurements of 
human body landmarks (eg. the SELSPOT system by SELSPOT AB, Sweden, and the
WATSMART System ??).  These use lateral photoeffect detectors [Lindholm and
Oberg, 1974; Woltring and Marsolais, 1980] to determine the position of a
spot of light projected (using a camera lens) over its surface.  In escence,
the detector is a large photodiode with four cathodes (one on each of the
four sides of the square detector crystal) and a single anode (the back of
the crystal).  A spot of light will produce currents which are proportional
to the position of the spot on the detector's face.  Let's try some ASCII
graphics in 2-D (so the detector has two cathodes to detect linear position)



              -------------------------> 1
             |                       |
             |                       |       |\
           -----   cathode 1         |       |  \
           XXXXX                     ________| +  \
           XXXXX|                            |      \        -------
    light >XXXXX|                            |        \_____ divider __ output
           XXXXX|     |                      |        /      -------
           XXXXX|-----| |--                  |      /           |
           XXXXX|   + |    |         ________| -  /           1 + 2
           XXXXX|         --- gnd    |       |  /
           XXXXX|         \ /        |       |/
           XXXXX| anode              |
           XXXXX                     |
           ----- cathode 2           |
             |                       |
             |                       |
             --------------------------> 2

If the dot of light from the LED is the ONLY source of light, then the position
of the projection is given by this circuit regardless of the level of illumina-
tion (the divider is used to normalize relative to total received power).  When
this circuit is used in the presence of other sources of light, then the way of
"tuning" to it is to sample for a few msec the background signal, light the LED
for an equal time and sample that signal separately.  The difference between
the two is the position of the LED.

Hamamatsu photonics sells linear and 2-D lateral photoeffect detectors, and
they also sell the required signal processing electronics.  The ready-made
systems by SELSPOT and others are NOT cheap ... 

Lindholm, L.E., and K.E. Oberg, "An Optoelectronic Instrument for Remote
On-Line Movement Monitoring", Biotelemetry, 1, 94-95, 1974.

Woltring, H.J., and E.B. Marsolais, "Opto-Electronic (SELSPOT) Gait Measure-
ments in Two and Three Dimensional Space - A Preliminary Report", Bull. Pros-
thetics Research, 46-52, 1980.

Most probably this technique can provide you with a much more accurate
measurement than you need, but I think that its simplicity beats scanning
a quadrant detector with a pan/tilt system until you reach zero difference.

            - David



+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 53847
From: kushmer@bnlux1.bnl.gov (christopher kushmerick)
Subject: infra red position encoders

I am looking for information on infra red based position encoders.

The idea would be to bounce the infrared source off a wall and the device would
read out the distance.

preferable it would be rs-232 addressable.



Any leads?


-- 
Chris Kushmerick
kushmer@bnlux1.bnl.gov
--I found my niche in life, I just didn't fit in.

Newsgroup: sci.electronics
document_id: 53848
From: pierson@cimill.enet.dec.com (Dave Pierson)
Subject: Re: Swr Meter For Cb Radios

In article <734953838.AA00508@insane.apana.org.au>,
peter.m@insane.apana.org.au (Peter Tryndoch) writes...
>AllThe Devil ReincarnateSWR meter for CB radios
> 
>TD>From: ssave@ole.cdac.com (The Devil Reincarnate)
>TD>Organization: CDAC, WA
>TD>What
>TD>is a good choice for a CB? 1/4 or 1/8 wave?
>TD>  I read the installation instructions on a 1/4 wave antenna,
>TD>and they suggested that I use an SWR to tune it at channel 12
>TD>and channel 32 for a minimum reading.  Question is, why channel
>TD>12 and 32?

>The best antenna is one that will let out the most wave (probably not the 
>best explanation, but the rest makes sense) A one wave will cancell itself 
>out (BTW no such beastie).
	Yes there is.  Not common for CB.  The pattern is different (sort of
	a cloverleaf, with four main lobes.

> The best is a 1/2 wave antenna, followed by 1/4, then 1/8 etc.
	Use of anything under 1/4 wave for transmitting is very uncommon.  (The
	usual "rubber duck" uses a coil to fool itself into looking like a
	quarter wave.
	I reccomend the ARRL Antenna Handbook, or a good basic book.

thanks
dave pierson			|the facts, as accurately as i can manage,
Digital Equipment Corporation	|the opinions, my own.
40 Old Bolton Rd		|I am the NRA
Stow, Mass 01775 USA		|pierson@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles

Newsgroup: sci.electronics
document_id: 53849
From: chin@ee.ualberta.ca (Jing Chin)
Subject: Need Info on DSP project

I want to start a DSP project that can maniplate music in a stereo cassette. 
Is that any chip set, development kit and/or compiler that 
can equilize/mix music?  Ideally, The system should have D/A A/D converters &
a DSP compiler.  A rough estimate of the cost is greately appreciated.

Thanks in advance.

Regards,
Jing Chin
e-mail address:chin@bode.ee.ualberta.ca

Newsgroup: sci.electronics
document_id: 53850
From: gray@feline.uucp (Kelly Gray)
Subject: Re: Pinout needed for TIL311

 According to my TI databook, the pinouts for the TIL311 display are as
follows:
 
 Pin 1 - LED supply voltage
 Pin 2 - Latch data input B
 Pin 3 - Latch data input A
 Pin 4 - Left decimal point cathode
 Pin 5 - Latch strobe input
 Pin 6 - Omitted
 Pin 7 - Common ground
 Pin 8 - Blanking input
 Pin 9 - Omitted 
 Pin 10 - Right decimal point cathode
 Pin 11 - Omitted
 Pin 12 - Latch data input D
 Pin 13 - Latch data input C
 Pin 14 - Logic supply voltage, Vcc
 
The logic supply voltage is 5V @ 60-90mA. The LED supply is also 5V, but
it need not be particularly well regulated. The LED drivers on the chip
use a constant current source, so LED intensity is not affected by the
supply voltage.
 

-- 

<o_o>    Kelly Gray
         gray@feline.uucp (preferred)
         gray@admin.humberc.on.ca

Newsgroup: sci.electronics
document_id: 53851
From: mblock@reed.edu (Matt Block)
Subject: Re: How to the disks copy protected.

In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>---
>
>I was wondering, what copy protection techniques are avaliable, and how
>effective are they?  Has anyone have any experience in this area?
>
>                      With highest regards,
>                           Babak   Sehari.

	Uh oh...
	Umm, there are a number of copy protection schemes.  Some involve
modifying the physical media, and some involve encryption schemes, &c.
	All of the ones that have existed over the course of computing have
been successful for a time.  I recall, however, near monthly releases of new
ways to "crack" the copy protection scheme of the latest releases.  The fact
is, none of them are completely secure, or anywhere near it.  Some are more or
less difficult to crack, and some have already been cracked.
	I guess what I am saying is that your question is difficult, if not
impossible, to answer.  What exactly do you want to know?  Do you need a good
one for a project you are working on?  How secure must it be?  Are you trying
to crack one that someone else has used?  I can probably make suggestions,
assuming the activity is strictly legal.  (In general, it is a BAD idea,
legally, to tamper with copy protection.  It can also lead to corruption of
files which you necessarily do not have back ups of (being as they are copy
protected,) which can be devestating.)  Do you have absolutely no ideas for
practical applications, and are merely curious?
	Please clear up those questions, and I'll try to help as much as I
can.

	Incidentally, the "Uh oh..." at the top is indicative of the dread
anyone who has watched their friends hacking equipment be carted off feels
when they are asked how to hack.  The area you are broaching is wrought with
dangers, many of which include breaking the law, or at least addressing it
(from one side or the other.)

Matt

Newsgroup: sci.electronics
document_id: 53852
From: moselecw@elec.canterbury.ac.nz (moz [chris moseley])
Subject: Re: Building a UV flashlight

jhawk@panix.com (John Hawkinson) writes:
> My main question is the bulb: where can I get UV bulbs? Do they
> need a lot of power? etc., etc.


he ones I have seen are all fluorescent tubes. Maybe you could find a
small tube to go in one of those hand-held fluoro lanterns?

> One other thing: a friend of mine mentioned something about near-UV
> light being cheaper to get at than actual UV light. Does anyone
> know what he was referring to?

Blue lights. Ultra-violet (by definition?) goes from the blue end of the
spectrum that people see to the radio spectrum (X-rays, cosmic rays etc).

possibly you could get light at the fringe of visibility (which people
with false eye-lenses can see easily, since it's your lenses that soak up
most of the UV), however since most people use UV to get other things
to `glow', and the near-blue is less energetic, it would probably not
work as well, if it worked at all. (lecture on basic atomic physics
fits in here, about electron transitions (quantum leaps) and stuff.

moz

Newsgroup: sci.electronics
document_id: 53853
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Power, signal surges in home...

In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Douglas S. Rand) writes:
>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:
>
>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>   that a ham would be running that kind of power from a car.  Ham rigs
>
>Not possible either.  You'd need about a 300 amp alternator for
>just the amplifier.  I can just see it.  You need to slow
>down on a downgrade,  so you hit the push to talk button.

Now, that indeed is possible.  A good friend of mine is running about 1 KW
PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
the rig an "electronic brake" since the engine noticeably slows when the
key is down.

My car, unfortunately, has so much computer junk under the hood that it's
astonishingly sensitive to RFI.  If I key a 2W HT over the engine with
the hood open, the car loses timing due to the RF leaking into the 
distributor pickup.  Very poor design.

I will, however, point out that ham radio operators are usually quite willing
to help when interference is detected.  Remember that any interference is
wasted power; if I put out 1W in the TV band, that's 1W that I am not putting
out in the band I am trying to transmit on, and 1W can often be the difference
between a nice card hanging on the wall, and nothing.  CBers, however, are
usually not as helpful.  Most illegal CBers, however, will stop operation
when you inform them of a problem.  The rest of them will stop operation when
you inform the local FCC office of the problem (in writing, and giving details
and addresses).

>Last, you can usually tell ham radio vs. CB.  Ham operators are
>required to declare their call (sign) every so many minutes (no more
>than 10).  So if you hear "This is WA1QT" or some other call starting
>with A, W or K and no more than 6 total characters, you heard a ham.
>CB'ers probably won't sign (I don't know that they're even required
>to) and fire/police have other private ids.

Good advice.  Hams will frequently give their call, and will never use
a "handle."  They are less apt to use immense amounts of profanity as well,
but that's not to say that they don't from time to time.  
--scott

Newsgroup: sci.electronics
document_id: 53854
From: avm1993@sigma.tamu.edu (MAMISHEV, ALEXANDER VALENTINO)
Subject: digital voltmeter - how does it work?

     Hello, 

   Let me introduce a problem:

   When I measure a sinusoidal wave (voltage) with a digital voltmeter, using 
AC mode, my output is an rms value (a peak value over 2 squared). / Right? / 
   When I measure a square wave in the same mode (AC), my output is equal 
to a peak value, actually, to the upper flat boundary of the wave.
   I assumed, that a digital voltmeter makes some kind of integration of the 
input value, and divides it over the wave period. / Right?/
   Now, I used it to measure the same  square wave as above, but distorted 
by high-frequency harmonics. Ideally, output should be the same, but...
The output value was only about 10% of the previous one! 
   Why? What is the nature of this output value? What does the voltmeter 
actually measure? And what does it show?  

   Related question (less important to me):
   What are advantages and disadvantages of digital voltmeters to compare with 
analog ones? 

   Thank you for your attention, you could mail me your opinion at
avm1993@zeus.tamu.edu or open a discussion here. I would appreciate either 
way.


Alexander V. Mamishev

____________________________________________________________________________
Power System Automation Laboratory    <>   phone office (409) 845-4623    
Department of Electrical Engineering  <>   phone home   (409) 846-5850
Texas A&M University                  <>   fax   (409) 862-2282
College Station, TX 77843, USA        <>   Internet: avm1993@zeus.tamu.edu
----------------------------------------------------------------------------


Newsgroup: sci.electronics
document_id: 53855
From: f92anha@fy.chalmers.se (Anders Hammarquist)
Subject: Re: Need to find out number to a phone line

In article <23321@mindlink.bc.ca> Sean_Oliver@mindlink.bc.ca (Sean Oliver) writes:
>> Joseph Mich Krzeszewsk writes:
>>         890 the phone company will read the number of the phone you are on
>
>Where I live, I use BCTEL. The number to dial is 211 for the same result.
>

In NY City, the number to dial is 958... It seems to be different in different
areas.

Anders

Newsgroup: sci.electronics
document_id: 53856
From: gunnarh@dhhalden.no (GUNNAR HORRIGMO)
Subject: Re: How to the disks copy protected.

In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:

>I was wondering, what copy protection techniques are avaliable, and how
>effective are they?  Has anyone have any experience in this area?
>
>                      With highest regards,
>                           Babak   Sehari.

One of the easiest, and really very used ways of copyprotection, is to mark 
a specific sector on the installation disk bad. This is very easy to get 
around, though, if you have any knowledge of hw-hacking, but most 'normal' 
users (yes those lowly key-punchers) don't. Whatever you do, please do 
_not_ use a hardware key. These were very popular a few years ago, and they 
STINK!!

MAIL-mail: gunnarh@sofus.dhhalden.no    SNAIL-mail: Gunnar Horrigmo
           gunnarh@fenris.dhhalden.no               Oskleiva 17
                                                    N-1772 Norway
----------------------------------------------------------------------
Disclaimer: The above posting may seem like insignificant rubbish at 
first glance, but if you read between the lines, you will be 
surprised to discover the annals of Burt Bacharach, world peace, 
Oxford Advanced Readers Dictionary, quantum physics made easy, and an 
easy-to-use step-by-step walkthrough on how to make a time travelling 
device that actually works.

Newsgroup: sci.electronics
document_id: 53857
From: edhall@rand.org (Ed Hall)
Subject: Re: Building a UV flashlight

In article <C5r6Lz.n25@panix.com> jhawk@panix.com (John Hawkinson) writes:
>One other thing: a friend of mine mentioned something about near-UV
>light being cheaper to get at than actual UV light. Does anyone
>know what he was referring to?

I don't want to get into a semantic argument, but contrary to some other
postings "near UV light" /is/ "actual UV light."  The "near" means that
it is close to the visible spectrum (i.e. of relatively long wavelength),
not that it is "nearly UV."  (I'm sure you can figure out now just what
"far UV" is.)

Regular incandenscent flashlight bulbs emit tiny amounts of UV in the
near end of the spectrum, such that a filter can be used to remove the
visible light and thus create a weak UV source.  Stronger sources are
going to require gas (probably mercury vapor) discharge tubes (such as
fluorescent tubes with UV phosphor).  Be careful, though; strong UV
sources can cause physiological damage, especially to the eyes.  The
shorter wavelengths are the most dangerous.

It wouldn't project a beam like a flashlight, but replacing the tubes
in a portable fluorescent lantern with UV tubes would be a relatively
cheap way to create a portable source.  It would be bright enough to
be useful, but not dangerously so.

		-Ed Hall
		edhall@rand.org

Newsgroup: sci.electronics
document_id: 53858
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Power, signal surges in home...

kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:

>My car, unfortunately, has so much computer junk under the hood that it's
>astonishingly sensitive to RFI.  If I key a 2W HT over the engine with
>the hood open, the car loses timing due to the RF leaking into the 
>distributor pickup.  Very poor design.

There was a news article a little while ago reporting a type of car (was
it a Volvo?) was found to stall if you used a certain brand/model of cellular
phone in it.  I seem to remember the car was recalled to fix the problem.

Hmmmmm... this has possibilities:
If the police are in pursuit of a vehicle, maybe they can bombard it with
high energy RFI.  :-)


Newsgroup: sci.electronics
document_id: 53859
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help wanted

In article <1993Apr20.071549.24839@csc.canberra.edu.au>, u934132@student.canberra.edu.au (Ogawa / Taro Stephen (ISE)) writes:
|> Could someone please tell me if a 1/4 decoder is the same as a 1 to 4
|> demultiplexer. I know how to link 2 of these to get an 8 output circuit,
|> but how do I link 5 of these to make a 1/16 multiplexer. Sorry if this
|> seems like a lame question, but I'm only a newbie to electronics, and I
|> have to do this circuit. Please make any mail as droolproof as possible.
|> 
|> 				 Thanx,
|> 					Taro Ogawa
|> 					(u934132@student.canberra.edu.au)

A 1 of 4 decoder need not be the same as a 1 to 4 demultiplexer, although
many commercial SSI implementations allow you to use one as such. Strictly,
a 1 of 4 decoder need only take two lines in and make one output change
state, according to the inputs.

A demux, on the other hand, uses two control inputs to determine which
of four outputs will reflect the state of the input signal. So there are
three inputs required.

A decoder can be used as a demux if it is equipped with an output enable
input, since this can be used as the data input (e.g. when high, all
outputs are high; when low, only the selected (by control inputs) output
will be low).

An eight way decoder is created by using the high order bit (bit 2) to
select which of two four way demuxes is enabled. Thus you achieve your
aim of having only one output of eight reflecting the input bits. Note
that this method cannot be used to create a true eight way demux, since
you have no data input (the enable line on a four way decoder) left
once you commit the enable lines to their intended purpose.

A sixteen way decoder obviously requires four, four-way decoders, plus
a mechanism to enable only one of the four at a time. Therefore, use
the fifth decoder, attached to the two high order bits, to provide the
four enable lines.

Of course, the two low order bits must be connected in parallel to the
four final stage decoders.

Please give me the credit when you submit your homework.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53860
From: baden@inqmind.bison.mb.ca (Baden de Bari)
Subject: *]] MOSFET help...

 
        Since I'm not all too keen on this area of hooking them up, I'm 
asking for help.  I know better than to hook a 12v, 1a stepper line to 
one, unless it can take it; however what about if I've got a 24-60v 
stepper.  What sort of curent limmiting circuitry would be involved (a 
small schematic would probably be helpfull).  
        Also, I've looked into the TIPC2701N by TI, and I was wondering 
if I should use the same suggested (by you replying to this message) 
current limiting circuitry on each of the 7 mosfets in the package as 
that illustrated in the schematic (which you the replyer would hopefully 
help me with).
 
                                ... hmm... different request... 
 
                Thanks.

 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

baden@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 53861
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: minimal boolean circuit

In article <1993Apr9.041505.8593@ringer.cs.utsa.edu> djimenez@ringer.cs.utsa.edu (Daniel Jimenez) writes:
>Suppose we have a boolean function which is a minimal sum-of-products
>(derived from a K-map or something), like this:

>f(a,b,c,d) = bc'd' + acd' + abc' + ab'c
>
>The books on logic design I have consulted all seem to imply that this
>is where the analysis ends  ...  But by factoring out the
>`a' term in the function, we can get fewer gates:

>f(a,b,c,d) = bc'd' + a(cd' + bc' + b'c),

>which yields 9 gates. 

	Yes, but... the minimization of gates is important in part
because of TIMING considerations.  A TTL gate has the basic structure
of AND/OR/INVERT, and an inversion of a sum of a product is just
exactly ONE gate delay.  The reason to find a minimal sum of products
is that this matches a hardware optimization.

	A positive-OR gate (such as the 9-gate solution uses) has
TWO gate delays (and there's another gate delay in the second term)
so that the second solution, while simpler in logic symbols, can 
be expected to be something less than optimal in the real world.
ECL is similar to TTL, in that it can support an OR/AND
gate with the minimum delay (unlike TTL, you get both true and
inverse outputs for 'free' when using ECL).

	PALs are basically large programmable AND/OR/INVERT
gates (with your choice of internal connections between the
various sections, and perhaps some latches), so a minimum sum
of products ALSO is a way to shoehorn a logic design into 
a few PALs.  It's not comparably easy to design with a minimization
of logic gates, but some software packages claim to allow you to
do so, and will take just about any mess of gates (as a nodelist
with 74xxx series logic ICs) and produce a description of
a logic cell array to do the same job.  Xilinx's XACT software
does this by treating each logic block as a macro, and expanding
it all out, then simplifying.

	John Whitmore

Newsgroup: sci.electronics
document_id: 53862
From: blockley@csu.murdoch.edu.au (Adrian Blockley)
Subject: integrated cct-type UM82C452L manufac by UMC.

where can I buy 1 or 2 of these chips (pref in Australia)?
What is name and address of `UMC'?

Dan

--

----------------------------------------------------------------------
Adrian Blockley                    ! I may say something profound   
Environmental science              ! here one day.                  
Murdoch University                 !                          
Western Australia, 6153            !                               
blockley@essun1.murdoch.edu.au     !                                
phone 09-360 2737                  !
----------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53863
From: jeff@nsr.hp.com (Jeff Gruszynski)
Subject: Re: digital voltmeter - how does it work?

MAMISHEV, ALEXANDER VALENTINO (avm1993@sigma.tamu.edu) wrote:
:      Hello, 
: 
:    Let me introduce a problem:
: 
:    When I measure a sinusoidal wave (voltage) with a digital voltmeter, using 
: AC mode, my output is an rms value (a peak value over 2 squared). / Right? / 
:    When I measure a square wave in the same mode (AC), my output is equal 
: to a peak value, actually, to the upper flat boundary of the wave.
:    I assumed, that a digital voltmeter makes some kind of integration of the 
: input value, and divides it over the wave period. / Right?/
:    Now, I used it to measure the same  square wave as above, but distorted 
: by high-frequency harmonics. Ideally, output should be the same, but...
: The output value was only about 10% of the previous one! 
:    Why? What is the nature of this output value? What does the voltmeter 
: actually measure? And what does it show?  


Re: RMS readings

Unless the DVM *says* it's measuring RMS, it's probably Average voltage.
The input is diode rectified and measured as DC.  If it says it's RMS
and but measures square/triangle/etc.  incorrectly, it's measuring
average and multipling by a correction that's *only* true for sine waves
(i.e.  Vave*(0.707/0.63) = Vrms).  If you want correct RMS for (most)
any waveform, you need a "True-RMS" DVM/DMM which literally does the
Root-Mean-Square calculation in either analog or digital circuitry.

: 
:    Related question (less important to me):
:    What are advantages and disadvantages of digital voltmeters to compare with 
: analog ones? 

The last significant advantage of analog (IMO) ** was ** being able to
"see" the signal if it was changing over time (e.g.  checking
electrolytic capacitors).

Anymore, most DMM have bargraphs, etc. that duplicate this.

: 
:    Thank you for your attention, you could mail me your opinion at
: avm1993@zeus.tamu.edu or open a discussion here. I would appreciate either 
: way.
: 
: 
: Alexander V. Mamishev
: 
: ____________________________________________________________________________
: Power System Automation Laboratory    <>   phone office (409) 845-4623    
: Department of Electrical Engineering  <>   phone home   (409) 846-5850
: Texas A&M University                  <>   fax   (409) 862-2282
: College Station, TX 77843, USA        <>   Internet: avm1993@zeus.tamu.edu
: ----------------------------------------------------------------------------
: 

--
================================================================================
Jeff Gruszynski
Semiconductor Test Equipment
Systems Engineer
Hewlett-Packard
================================================================================
(415) or T 694-3381
jeff@hpmvd061.nsr.hp.com
jeff@hpuplca.nsr.hp.com
================================================================================

Newsgroup: sci.electronics
document_id: 53864
From: dnewman@lynx.dac.northeastern.edu (David F. Newman)
Subject: arcade style buttons and joysticks

Hi there,
Can anyone tell me where it is possible to purchase controls found
on most arcade style games.  Many projects I am working on would
be greatly augmented if I could implement them.  Thanx in advance.

-Dave
dnewman@lynx.dac.northeastern.edu


Newsgroup: sci.electronics
document_id: 53865
From: elliott@optilink.COM (Paul Elliott)
Subject: Re: Analog switches/Balanced Demodulators

In article <msf.734832494@skaro> msf@skaro.as.arizona.edu (Michael Fulbright) writes:
>I am trying to build a synchronous demodulator and I've hit a snag.
>In my application I want to be able to change the gain of an
>op amp amplifier from 1 to -1, controlable via a digital input.
>The most obvious way I've come up with is to use analog switches
>to adjust the gain of the op amp. The only analog switch I have
>experience with it the 4066. Unfortunately I want to switch an
>AC signal which goes from about -5V to 5V, and the 4066 is only
>for positive signals.
>[...]
> I have a carrier signal which varies between 0V and +5V. I want
>to demodulate an input signal by feeding the input signal thru a
>amp with a gain of 1 when the carrier is at +5V, and thru a amp
>with a gain of -1 when the carrier is 0V. The output is then
>low pass filtered. I believe this is called lock in detection as well
>as synchronous demodulation.

Look at the 4053.  This is a triple 2-to-1 transmission-gate analog
multiplexer, with positive and negative power supplies (can be run
from a single-ended supply as well).  With dual supplies, the logic
inputs still range from ground (0 Volts) to VDD.

This is a neat (well, I think so) design for a switchable-polarity
amplifier:

                 +-----/\/\/\-------+
                 |                  |
                 |    /--------\    |
INPUT -+-/\/\/\--+----| -      |    |
       |              |  opamp |----+------- OUTPUT
       +-/\/\/\--+----| +      |
                 |    \--------/
                 |
CONTROL	---------X (analog switch)
                 |
                 |
                ---
                GND

All resistors are equal-value.  When the analog switch is closed,
the amp is inverting-gain-of-one.  With the switch open, it is
non-inverting-gain-of-one.  You can clean up the circuit to trim
out input offset current if this hurts the balance (this would show
up as carrier feed-through).

For high frequencies, the slew-rate of the opamp might cause problems,
especially if it isn't symmetrical (and it usually isn't).

-- 
--------     Paul Elliott - DSC Optilink - Petaluma, CA USA      ----------
    {uunet,pyramid,tekbspa}!optilink!elliott -or- elliott@optilink.com
       "I used to think I was indecisive, but now I'm not so sure."


Newsgroup: sci.electronics
document_id: 53866
From: rogerw@world.std.com (Roger A Williams)
Subject: Re: 68HC16 public domain software?

Doesn't Motorola AMCU have something on the BBS yet? (512-891-3733)

Newsgroup: sci.electronics
document_id: 53867
From: sehari@iastate.edu (Babak Sehari)
Subject: Re: How to the disks copy protected.

In <1993Apr20.230749.12821@reed.edu> mblock@reed.edu (Matt Block) writes:

>In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>>---
>>
>>I was wondering, what copy protection techniques are avaliable, and how
>>effective are they?  Has anyone have any experience in this area?
>>
>>                      With highest regards,
>>                           Babak   Sehari.

>	Uh oh...
>	Umm, there are a number of copy protection schemes.  Some involve
>modifying the physical media, and some involve encryption schemes, &c.
>	All of the ones that have existed over the course of computing have
>been successful for a time.  I recall, however, near monthly releases of new
>ways to "crack" the copy protection scheme of the latest releases.  The fact
>is, none of them are completely secure, or anywhere near it.  Some are more or
>less difficult to crack, and some have already been cracked.
>	I guess what I am saying is that your question is difficult, if not
>impossible, to answer.  What exactly do you want to know?  Do you need a good
>one for a project you are working on?  How secure must it be?  Are you trying
>to crack one that someone else has used?  I can probably make suggestions,
>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>legally, to tamper with copy protection.  It can also lead to corruption of
>files which you necessarily do not have back ups of (being as they are copy
>protected,) which can be devestating.)  Do you have absolutely no ideas for
>practical applications, and are merely curious?
>	Please clear up those questions, and I'll try to help as much as I
>can.

>	Incidentally, the "Uh oh..." at the top is indicative of the dread
>anyone who has watched their friends hacking equipment be carted off feels
>when they are asked how to hack.  The area you are broaching is wrought with
>dangers, many of which include breaking the law, or at least addressing it
>(from one side or the other.)

>Matt

I have written a program and I want to market it.  I would like certain degree
of protection, since my main custmers are individuals and not the 
cooperations.   I know laser hole burning method, and hardware key method,
however, my  software is going to cost only $15.00, so I can not afford that.
Also, at this low price I can not afford people make too many copy of my
software. Well, I guess say upto %20 illigal copying is ok by me.

However, I do not want someone to get a copy of PCTools and copy my software.  
Off course, I never meant to forbid the true hackers from copying, since they
can develope a better program anyway.

                      With highest regards,
                           Babak   Sehari.


-- 

Newsgroup: sci.electronics
document_id: 53868
From: patter@dasher.cc.bellcore.com (patterson,george r)
Subject: Re: Power, signal surges in home...

In article <1993Apr20.232804.24632@mprgate.mpr.ca> vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>
>>My car, unfortunately, has so much computer junk under the hood that it's
>>astonishingly sensitive to RFI.  
>
>Hmmmmm... this has possibilities:
>If the police are in pursuit of a vehicle, maybe they can bombard it with
>high energy RFI.  :-)

Right. So all the cops will be buying antique muscle cars for chase cars;
otherwise the *police* cars will die too!

-----------------------------------------------------------------------
                    | To get the attention of a large animal, be it an
                    | elephant or a bureaucracy, it helps to know what
George Patterson -  | part of it feels pain. Be very sure, though, that
                    | you want its full attention.
                    |                            Kelvin Throop
-----------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53869
From: dale@access.digex.com (Dale Farmer)
Subject: Re: Building a UV flashlight

John Hawkinson (jhawk@panix.com) wrote:
: Yes, I know it sounds crazy. Call it an urge. Call it what you want.
: Just don't ask why :-)

: Anyway, I'd like to build a UV flashlight, cheaply. "flashlight" means
: it should be reasonably portable, but could have a power pack if
: necessary.

: My main question is the bulb: where can I get UV bulbs? Do they
: need a lot of power? etc., etc.

: I'm not too concerned with whether it's long-wave or short-wave
: (but hey, if anyone has a cheap source of bulbs, I'll take both).

	Check out a medical supply catalog, the thing you are looking for
is called a woods lamp (so you can check for woods sign, certain skin
conditions flourecse (sp) under UV light)  They come in disposable
penlight like types and larger ac powered types.  It is also used in eye
examinations, a flourescent dye is introduced to the surface of the eye,
then UV is shined on it, shows up scratches and abrasions very clearly
that would otherwise be very difficult to detect.  (for the completest the
dye is called flouescien, and in normal light appears orangish, and leaves
a mild burning sensation to the eye for 10-15 minutes, until the tears
flush it all out.  

Have fun.

--Dale Farmer




Newsgroup: sci.electronics
document_id: 53870
From: umlangston@msuvx1.memst.edu (Mark C. Langston)
Subject: _negative_ logic high?

  This may sound like a simple-minded question, but this is the first time
I've ever had a need for this:

I've been designing some relatively simple chip circuits based on things
like photoresistors (you know, no light to photoresistor, emit a logic
high, etc.).

Anyway, I've got some servos lying around, and I wanted to do some things
with them using digital logic.  I know all about having to pulse the signal
and everything, I just have one problem:  I'm assuming I need a negative
(yes, negative) logic high to get the thing to turn in the direction 
opposite the direction it would turn under normal logic high.

Is a negative logic high (I've seen this in schematics) the same thing as
an active low, or what?  I'm not using a bi-polar power source, so how
would I get a negative logic high out of this thing?  I need to have all
three signals available:  Logic high, logic low, and negative logic high.

Any help would be greatly appreciated.  Also, please reply via email, as I
never seem to have time to read this (or any other) group lately.

Thanks much,
-mark

umlangston@memstvx1.memst.edu




Newsgroup: sci.electronics
document_id: 53871
From: randyd@csd4.csd.uwm.edu (Randall Elton Ding)
Subject: Re: ADCOM GTP500II IR sensor & repeater spec's?

In article <1r1996INNijp@hp-col.col.hp.com> johnr@col.hp.com (John T. Rasper) writes:
>Does anyone know the details of the interface (5 wire din) for the
>IR remote sensor & (2 wire IR repeater) for the ADCOM GTP-500II
>preamp?  The ADCOM part numbers are the XR-500II, SPM-500II, and 
>IRA-500II.
>
>A cursory physical examination of the pre-amp connector indicates
>that the connector (5 pin din) may provide: (Viewed from connector front)
>
>      |
>   5     1     (pin ?) +?v @ ???mA
>    4   2      (pin ?) +/-?v @ ???mA
>      3        (pin 3) Signal Ground
>               (pin ?) Demodulated signal ?V-pp, ? polarity, ? mA drive
>               (pin ?) Signal to drive repeater LED (drives through 150ohm
>                       resistor) ?V-pp
>
>I assume that the repeater connectors (mini-plugs) drive the IR repeater
>LED's directly.  True?
>
>Can anyone fill in the ?'s.  Thanks.
>

Here's the scoop.  When you get your home brew receiver working, would
you be willing to share it with the rest of us?  I always wanted to
build my own but never have the time to fool around and design it.

pin 1:  signal ground
pin 2:  signal
pin 3:  always hot +6 volts
pin 4:  +6 volts, hot only when preamp is turned on
pin 5:  infrared repeater connectors

The infrared repeater jacks on the back of the preamp are not connected
to anything inside the preamp except the 5 pin connector pin #5.  There
is a 150 ohm resistor between the two jacks, with a 1.5K from pin 5 to
ground.

The signal pin #2 in the preamp is summed with the built in IR receiver.
They use a chip called CX20106A and a BJT to amplify the signal.  I would
imagine the logical way would be to duplicate this circuit and use
it as the external receiver.

If you need more info, let me know.

Randy      randyd@csd4.csd.uwm.edu



Newsgroup: sci.electronics
document_id: 53872
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: Radar detector DETECTORS?

>>>  Are any brands "quieter" than others?

>Yes some radar detectors are less detectable by radar detector
>detectors. ;-)

I have a Bel-966.
I just looked at the manual yesterday... and it does indeed claim to be
undetectable by RDD's.


Pat

Newsgroup: sci.electronics
document_id: 53873
From: gerrit@laosinh.stgt.sub.org (Gerrit Heitsch)
Subject: Re: 6551A and 6551 compatibility

In article <C5owvs.pr@world.std.com>, Internet Surfer writes:

> Does any one know if the 6551 is timing/pin compatible with the 6551.. 

No, the 6551A is able to operate in a 2 MHz system, the 6551 can only
take 1 MHz without problems.

If you see a 8551 made by MOS or CSG, take it, its a 6551A.

> It seems the 6551 has in iheirent bug with cts/rts handshaking and i need
> a suitable pin replacement to put in my serial card... possibly a buffered
> version perhaps?

I know no fixed version of the 6551. There are different possibilities
to work around this bug. The easiest is to tie _CTS to GND and
use _DSR or _DCD as _CTS. It should be easy to fix the software,
_DSR is bit 6 and DCD ist bit 5 of the Status Register (Read 6551
with RS1 = low and RS0 = high).

Using the _CTS-line can lead into big trouble. The 6551 _instantly_
stops transmission if _CTS goes high. This means, that you may
get only a half byte...

Gerrit

-- 
         Gerrit Heitsch  Moenchweg 16  7038 Holzgerlingen  Germany
  Logical adresses: UUCP: gerrit@laosinh.stgt.sub.org FIDO: (2:2407/106.9)
If we will ever be visited by Aliens, it will be very hard to explain, why a
 lifeform, that is intelligent enough to build atomic weapons can be stupid
   enough to do it. (taken from GEO special about space, page 88-91)

Newsgroup: sci.electronics
document_id: 53874
From: gerrit@laosinh.stgt.sub.org (Gerrit Heitsch)
Subject: Re: What's a good IC for RS232 -> TTL signals??

In article <C5nz60.99z@scraps.uucp>, Frank Holden KA3UWW writes:

> >I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
> >levels.  Something relatively inexpensive would be nice, too.  Anyone have
> >a suggestion??  Thanks.
> 
> Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
> you want.  They are selling it for about $3.50...

Are you sure that he needs a two way converter? If he wants only
RS232->TTL I would suggest the MC1489, its very cheap (0.80 DM in
Germany). This chip needs only +5V. The MC1488 TTL->RS232-Converter
uses +12V and -12V.

BTW... The MAX232 and compatibles seem to be expensive in the USA...
I paid 2.95 DM for a ITS80272 (made by Harris), its absolutely
compatible with the MAX232 or the ICL232.

Gerrit

-- 
         Gerrit Heitsch  Moenchweg 16  7038 Holzgerlingen  Germany
  Logical adresses: UUCP: gerrit@laosinh.stgt.sub.org FIDO: (2:2407/106.9)
If we will ever be visited by Aliens, it will be very hard to explain, why a
 lifeform, that is intelligent enough to build atomic weapons can be stupid
   enough to do it. (taken from GEO special about space, page 88-91)

Newsgroup: sci.electronics
document_id: 53875
From: rmah@panix.com (Robert Mah)
Subject: Re: electronic parts in NYC?

In <FRITZM.93Apr20225937@sun.panix.com> fritzm@panix.com (Fritz Mueller) writes:
>I just moved to NYC and wondered if there are any electronics hackers
>out there who could point me to places in NYC that sell individual
>electronic components (switches, pots, transformers, caps,
>...

Try Cables and Chips ... let me dig out a reciept ...

Here we are...

Cables & Chips at 121 Fulton Street, that's near South Street Seaport and 
Wall Street.  Phone is 212-619-3132 and 800-843-4117.

However, when ordering there, be VERY exact or there's a good chance they'll 
screw up.  Otherwise, they're pretty good, and they deliver too.

Cheers,
Rob
-- 
[----------------------------------------------------------------------]
[ Robert S. Mah   | Voice: 212-947-6507   | "Every day an adventure,   ]
[ One Step Beyond | EMail: rmah@panix.com |  every moment a challenge" ]
[----------------------------------------------------------------------]

Newsgroup: sci.electronics
document_id: 53876
From: fritzm@panix.com (Fritz Mueller)
Subject: electronic parts in NYC?

Hey all:

I just moved to NYC and wondered if there are any electronics hackers
out there who could point me to places in NYC that sell individual
electronic components (switches, pots, transformers, caps,
transistors, etc.)  "Radio Shack" doesn't count (they have almost no
selection, and their prices are outrageous!)

I have particular interest in audio components (amplifier IC's, power
MOSFETS, output transformers, tubes and tube sockets, pan pots,
faders, etc.)

I have checked out a lot of 48th street and Canal street so far with
no luck.  Am I missing places, looking in the wrong place, or do I
have to resort to mail order?

					thanks in advance,
					  --FritzM.

Newsgroup: sci.electronics
document_id: 53877
From: stevens@madvlsi.columbia.edu (Andy Stevens)
Subject: Re: decoupling caps - onboard

In article <1993Apr20.173652.762@jarvis.csri.toronto.edu>, ravin@eecg.toronto.edu (Govindan Ravindran) writes:
|>         I would like to know if any one had any experience with having
|> on-board decoupling capacitors (inside a cmos chip) for the power
|> lines. Say I have a lot of space left im my pad limited design.
|> any data on the effect of oxide breakdown? any info or pointers
|> are appreciated.

DEC did this on their new alpha chip.  I'm sure you could call them up
and ask them how they did it (haha).

Actually, there are some details in their article in IEEE Journal of
Solid-State Circuits.  I think it was sometime around Nov.  1992.

--andy s.

Newsgroup: sci.electronics
document_id: 53878
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: How to the disks copy protected.

In article <sehari.735357542@du139-213.cc.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>
>I have written a program and I want to market it.  I would like certain degree
>of protection, since my main custmers are individuals and not the 
>cooperations.   I know laser hole burning method, and hardware key method,
>however, my  software is going to cost only $15.00, so I can not afford that.
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.
>
>However, I do not want someone to get a copy of PCTools and copy my software.  
>Off course, I never meant to forbid the true hackers from copying, since they
>can develope a better program anyway.

I wouldn't bother with the copy protection, if I were you.  If you program
is any good, the pirates will have stripped the protection and will be
distributing the stripped version is well under a week.

Hardware methods prevent J. Random Loser from using his Copy II PC to pirate 
your software, but doesn't stop anyone who knows a few people with enough 
connections to "real" pirates who _will_ be able to defeat your "check for the 
hole" code.

You may want to price your software (depending on what it is) a tad
higher... a price change from $15 to $25 probably would turn off very few
potentials buyers, and that way you could tolerate more pirates (whose
numbers don't change with the price).

As for the 20% pirating figure... ha, ha.  Of course, a lot of pirates just
have this "thing" about having pirated software, even if they never use it,
so perhaps that really wouldn't count towards 20%.  Even so, 20% is awfully
low.


					---Joel Kolstad

P.S. -- I assume you're talking PC software.  If you're talking UNIX,
HP-48, or something else somewhat obscure, copy protection might be a
slightly more viable alternative.

Newsgroup: sci.electronics
document_id: 53879
From: mhald@lynx.dac.northeastern.edu (Mark Hald)
Subject: Re: Dayton Hamfest

I booked a hotel (Red Roof Inn) last week in Cincinnati (Blue Ash, which
is at the northern tip of the metro. Cincy area).  I chose it for a few
reasons.
  1.  All hotels in and near Dayton were booked solid.
  2.  This hotel is only costing $28/night.
  3.  It was one of about 4 rooms left on the night I reserved.
  4.  Cincinnati probably has more to to at night than Dayton.  I intend
      to hit the riverboat entertainment at dusk!

If anyone has other suggestions for nightlife, please let me know of
other hot spots.  Thanks!

Mark

Newsgroup: sci.electronics
document_id: 53880
From: skipper@traider.ersys.edmonton.ab.ca (Mark Bevan)
Subject: Re: Need to find out number to a phone line

alee@ecs.umass.edu writes:

> 
> Greetings!
>       
>         Situation:  I have a phone jack mounted on a wall.  I don't
>                     know the number of the line.  And I don't want
>                     to call up the operator to place a trace on it.
> 
>         Question:   Is there a certain device out there that I can
>                     use to find out the number to the line?
>         Thanks for any response.
>                                                     Al
> 
>   

Dial 511 and it sound tell you the number.

---
skipper@traider.ersys.edmonton.ab.ca (Mark Bevan)
Traiders of the Lost .ARC! - Edmonton, Alberta, Canada

Newsgroup: sci.electronics
document_id: 53881
From: cbruno@wpi.WPI.EDU (Christopher James Bruno)
Subject: Coil

Hey everyone, I'm new to this  newsgroup so please excuse me if this is a 
dumb question....I want to build a crossover for my stereo and I need
a coil with an inductance of 6.8mH (actually I need 4).  I was wondering
if anyone knew where I could buy these or how to make these.  I've called
many places and no one I can find sells them.  If you have the answers just
E - mail me....
Thanks in advance....
Chris




Newsgroup: sci.electronics
document_id: 53882
From: dave@imax.imax.com (Dave Martindale)
Subject: Re: A question about 120VAC outlet wiring.

jeh@cmkrnl.com writes:
>
>Hmmm.  How are those orange "isolated ground" outlets (often used in
>computer rooms) wired?  

They require two separate grounds.  One ground goes to the ground pin
of the outlet, and the other ground wire is connected to the outlet's
mounting tabs (and thus grounds the box and faceplate screw and metal
faceplate, if any).

The box/faceplate ground goes to the normal distribution panel ground.
The outlet ground-pin wire is generally connected to an insulated
busbar in the distribution panel which is, in turn, connected to
the building-entrance main ground by its own wire.

So the two separate ground systems are connected together at the
building's service entrance.  But one is also connected to every
grounded piece of electrical equipment in the whole building,
while the isolated ground is shared only by the equipment plugged
into isolated-ground outlets of that panel.  If someone happens
to accidentally short one phase of a 600V feeder to ground,
the main building ground is likely to have a lot of noise on it
until the breaker trips or the fuse blows, while the isolated
ground will remain relatively noise-free.

Newsgroup: sci.electronics
document_id: 53883
From: mtearle@gu.uwa.edu.au (Mark Tearle)
Subject: Re: Looking for Electronics Dept Info in Austrailia

hjkim@hyowon.pusan.ac.kr (Hojoong Kim) writes:

>Hi Netters!

>I am looking for the list of universities in Austrailia, which has electronics department. 
>I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
>But I don't have any information about Austrailian Universities.
>Can anybody recommend a good university in communication area?
>Any comments will be welcomed!

Can I suggest the University of Western Australia in Perth.
The weathers great, the people are great and our Electronic Engineering department is great.
I am a first year student here ... so I don't know much about what projects but I do know they have a good reputation in the fields of dsp and communications.  Ever heard of QPSX?  The people who own are ex-UWA ... so that gives an indication of what the department is like.

For more information
email: yianni@swanee.ee.uwa.edu.au
with the above request and he should be able to tell some more info

or write

Department of Electrical and Electronic Engineering
University of Western Australia
Stirling Highway
CRAWLEY 6009
Western Australia
Australia


Yours
Mark

mtearle@tartarus.uwa.edu.au
--
#***********************************************************************#
#  Mark Tearle                         |                                   #
#                                      |     
#  email: mtearle@tartarus.uwa.edu.au  |     

Newsgroup: sci.electronics
document_id: 53884
From: mtearle@gu.uwa.edu.au (Mark Tearle)
Subject: Re: Need to find out number to a phone line

Well here in Australia you dial 
11544
to get the number read back to you
if you live in the country include the area code of the nearest capital city
eg for wa 09 11544

Yours
Mark

--
#***********************************************************************#
#  Mark Tearle                         |                                   #
#                                      |     
#  email: mtearle@tartarus.uwa.edu.au  |     

Newsgroup: sci.electronics
document_id: 53886
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: ATARI 2600 Processors

In article <93110.125951PCA103@psuvm.psu.edu> <PCA103@psuvm.psu.edu> writes:
>Does anyone know what processor the Atari 2600 used? What I'm looking for is th
>e pin-outs for the Atari 2600.... the schematics for it it... does anyone have
>any idea where I could find this or any related information? This is very impor
>tant. Also, are the ROM chips that were used fo rthe 2600 games still available
>, or were they propreitary? Please email me with any responces, as this is very
> important.. Thanks a million...
>
>BTW- Anyone who works/has worked for Atari, I could really use your help with i
>nfo on the old 2600, please email me if you are willing to help me.... thatnks
>alot!!
>
>-Peter

The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
game machine). The 2600 had some extra ASIC chips that were basically
modified graphics chips and PIA's for the joysticks. Later model 2600
might have incorporated many of the chips into one ASCI, as the weight
of the machines and part count decreased a lot over the years.

Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
their games. I have no idea how much RAM it had to work with, but I
would hazard a guess of 2 or 4K RAM. Think comes from a lot of hacking
with the 800 and 130xe computers. And occasionally hacking with the
2600 (fixing it for monitor composite video use, and audio hookups).
Also I tryed to make a cartridge-less system that stored the ROM into
a RAM cartridge that could be loaded up at some prior time (a way to
backup cartridges). I've heard of a setup like this where games could
be bought (cheaply) on FSK-recorded tapes, then you would load them
into a special RAM cartidge, and play them.

Anyways, if you're interested in looking for 2600 equipment, we've got
two 2600 machines around (one composite A/V modified), and lotsa
cartridges. Willing to sell for reasonable offer + shipping and
handling. Don't play it anymore, since going to computers + Nintendo
(interested in that too?).

Hope that helps your question... I might grab some 6502's out too,
since they must be fun to play with (as microcontrollers).
-shishin "squish" yamada
squish@endor.harvard.edu

Newsgroup: sci.electronics
document_id: 53887
From: fishman@panix.com (Harvey Fishman)
Subject: Re: electronic parts in NYC?

There are also a couple or three places on West 45th between Fifth and
Sixth.  

Harvey


-- 
----------------------------------------------------------------------------
 Harvey Fishman   | 
fishman@panix.com | You don't get smart except by asking stupid questions.
  718-258-7276    |

Newsgroup: sci.electronics
document_id: 53888
From: ketil@edb.tih.no (Ketil Albertsen,TIH)
Subject: Re: How to the disks copy protected.

In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:

>	I guess what I am saying is that your question is difficult, if not
>impossible, to answer.  What exactly do you want to know?  Do you need a good
>one for a project you are working on?  How secure must it be?  Are you trying
>to crack one that someone else has used?  I can probably make suggestions,
>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>legally, to tamper with copy protection.  It can also lead to corruption of
>files which you necessarily do not have back ups of (being as they are copy
>protected,) which can be devestating.)  Do you have absolutely no ideas for
>practical applications, and are merely curious?
>	Please clear up those questions, and I'll try to help as much as I
>can.

May we interpret this as an offer to volunteer as editor for a
"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
an initiative! *I* will volunteer to ask some of the questions, if you will
provide the answers :-)

Ketil Albertsen

Newsgroup: sci.electronics
document_id: 53889
From: frode@dxcern.cern.ch (Frode Weierud)
Subject: Magstrip Card Reader Info


Can somebody please help me with information about an
American Magnetics Corporation Magstripe Card Reader that
I recently bought locally from a surplus dealer.

On the rear it has the following information:

	American Magnetics Corporation
	Carson, CA, USA
	Magstripe Card Reader
	Model 41,
	P/N 507500 - 2300112311

It is fitted with a cable with a RS232 Cannon 25-pin connector on
the end and has a separate power connector like the once used with
wall chargers.

Frode

**************************************************************************
*	Frode Weierud		Phone	:	41 22 7674794		 *
*	CERN, SL		Fax	:	41 22 7823676		 *
*	CH-1211 Geneva 	23	E-mail	:	frode@dxcern.cern.ch	 *
*	Switzerland			   or	weierud@cernvm.cern.ch	 *
**************************************************************************


Newsgroup: sci.electronics
document_id: 53890
From: elr@trintex.uucp (Ed Ravin)
Subject: Re: electronic parts in NYC?

Taft Electronics, 45th Street between 5th & 6th -- the only one left in
what was once an entire district of electronics stores.  A little expensive.

Trans-Am Electronics, Canal Street near 7th Ave -- lots of surplus type
stuff.

Several other electronics or "surplus" type places are still on Canal
Street.

I think Bronx Wholesale Radio is still in business -- Fordham Road not
too far from Arthur Avenue in the Bronx.  Also in the Bronx is NorthEastern
(or was it Northwestern?  Northeast Electronics?) on Jerome Avenue near
Bedford Park Boulevard.  They're mostly a TV parts supply house, but when
I was building CB radio projects, they were quite handy..
-- 
Ed Ravin               | "A TV cop fires a gun three times an hour.  A real cop
Prodigy Services Co.   |  fires a gun only once every five years."
White Plains, NY 10601 |------------d i s c l a i m e r - w a s - h e r e -----
+1-914-993-4737        | elr@trintex.uucp or elr%trintex@uunet.uu.net

Newsgroup: sci.electronics
document_id: 53891
From: wayne@uva386.schools.virginia.edu (Tony Wayne)
Subject: speaker impedance help needed

           I want to connect a very small "home-made" speaker
up to the headphone jack on my macintosh LC for an experiment.
The dc resistance of the speaker is 1 ohm.  Any ideas how I can
do this safely?  I think I need some kind of an impedance
transformer or something.?
-tony
 wayne@uva386.school.virginia.edu 

Newsgroup: sci.electronics
document_id: 53892
From: cfb@fc.hp.com (Charlie Brett)
Subject: FET-TRONS(sp?)

Has anyone ever heard of FET-TRONS (or is it FETRONS, FETTRONS, ...).
These were FET replacement modules for vacuum tubes. I'm looking for
applications where they were used. 

       Charlie Brett - HP Ft. Collins

Newsgroup: sci.electronics
document_id: 53893
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Los Angeles Freeway traffic reports

: While driving through the middle of nowhere, I picked up KNBR, AM 1070,
: a clear-channel station based in Los Angeles. They had an ad 
: claiming that they were able to get traffic flow information from 
: all of the thousands of traffic sensors that CalTrans has placed
: under the pavement. Does CalTrans sell this info? Does KNBR have
: an exclusive? What's the deal?

: ==Doug "Former L.A. commuter" Claar

You were right the second time, it is KNX. Believe it or not, I also
listen to KNX in the evenings here in Colorado! It's kind of fun driving
through the country listening to traffic jams on the 405. Back to your
original question. Yes, there are sensors just past every on-ramp and
off-ramp on the freeways. They're the same sensors used at most stoplights
now (coils in the pavement). You might want to give CalTrans a call or
even ask Bill Keene (KNX's traffic reporter). I doubt if just anyone can
get the information, but it would be worth asking just in case you can
get it.

      Charlie Brett (former LA commuter)  Ft. Collins, CO


Newsgroup: sci.electronics
document_id: 53894
From: v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Radio Electronics Free information card


	How does the radio Electronics free information cards work.
Do they just send you some general information about the companies that
advertise in their magazine or does it also give you sign you up for a
catalog. 


                                  Neil Gandler

Newsgroup: sci.electronics
document_id: 53895
From: bob@kc2wz.bubble.org (Bob Billson)
Subject: Re: subliminal message flashing on TV

kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan) says:
>Hi.  I was doing research on subliminal suggestion for a psychology
>paper, and I read that one researcher flashed hidden messages on the
>TV screen at 1/200ths of a second.  Is that possible?  I thought the

Take a look over in alt.folklore.urban.  There is a thread about subliminal
messages on TV.  The fact that subliminal messages don't work aside, an image
can't be flashed on a TV screen fast enough to not be noticed.
-- 
  Bob Billson, KC2WZ                          | internet: bob@kc2wz.bubble.org
  $nail:  21 Bates Way,  Westfield, NJ 07090  | uucp:     ...!uunet!kc2wz!bob

               "Friends don't let friends run DOS" -- Microware

Newsgroup: sci.electronics
document_id: 53896
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Laser vs Bubblejet?

FYI:  The actual horizontal dot placement resoution of an HP
deskjet is 1/600th inch.  The electronics and dynamics of the ink
cartridge, however, limit you to generating dots at 300 per inch.
On almost any paper, the ink wicks more than 1/300th inch anyway.

The method of depositing and fusing toner of a laster printer
results in much less spread than ink drop technology.

It doesn't take much investigation to see that the mechanical and
electronic complement of a laser printer is more complex than
inexpensive ink jet printers.  Recall also that laser printers
offer a much higher throughput:  10 ppm for a laser versus about 1
ppm for an ink jet printer.

Something else to think about is the cost of consumables over the
life of the printer.  A 3000 page yield toner cartridge is about
$US 75-80 at discount while HP high capacity (~500-1000 page yield)
cartridges are about $US 22 at discount.  It could be that over the
life cycle of the printer that consumables for laser printers are
less than ink jet printers.  It is getting progressively closer
between the two technologies.  Laser printers are usually desinged
for higher duty cycles in pages per month and longer product
replacement cycles.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53897
From: ragee@vdoe386.vak12ed.edu (Randy Agee)
Subject: Radar detector DETECTORS?

Several years back one of the radar detectors manufacturers, in
defiance to Virginia's law against radar detectors, passed out
thousands of fake cardboard radar detectors at truck stops near
the Virginia State lines.  At that time there were no radar
detector Detectors!  I am not sure of the impact but I would
imagine that enforcement of the law by visually sighting a
radar detector became difficult - if not impossible!

As I said earlier, efforts to throw out or eliminate the VA law
against radar detectors has been in vain.  In fact, effective
Jan. 1, 1993, the fine for possession of a radar detector
accessable to the driver of a vehicle in VA is now $250.00.  

I have noted an interesting anomality with my Alinco DR-100 2
meter ham transceiver.... It will make a *cheap* radar detector
scream!  I am not sure of the range, but it is obvious by the
brake lights that it can be at least 50 feet at 50 watts! :-)

==============================================================================
Randy T. Agee - WB4BZX           | At some point, you probably pondered The 
P.O. Box 2120 - 20th floor       | Meaning of Life, and you came up with a 
Virginia Department of Education | satisfactory answer, which has or has not
Richmond, VA 23216-2120          | stood the test of time, or you shrugged
Phone (804) 225-2669             | mightily, muttered "Beats the heck out of
ragee@vdoe386.vak12ed.edu        | me," and ordered a cheeseburger.
=============================================================================
 

Newsgroup: sci.electronics
document_id: 53898
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: How to the disks copy protected.

Write a good manual to go with the software.  The hassle of
photocopying the manual is offset by simplicity of purchasing
the package for only $15.  Also, consider offering an inexpensive
but attractive perc for registered users.  For instance, a coffee
mug.  You could produce and mail the incentive for a couple of
dollars, so consider pricing the product at $17.95.

You're lucky if only 20% of the instances of your program in use
are non-licensed users.

The best approach is to estimate your loss and accomodate that into
your price structure.  Sure it hurts legitimate users, but too bad.
Retailers have to charge off loss to shoplifters onto paying
customers; the software industry is the same.

Unless your product is exceptionally unique, using an ostensibly
copy-proof disk will just send your customers to the competetion.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 53899
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: 600RPM Floopy drives - UPDATE!

Many thanks to those who replied to my appeal for info on a drive I have
which is 3.5" 600RPM!!

I now have some information on how to modify this for use with a BBC B 
computer. Not only do you have to change the speed from 600 to 300 rpm
(tried that) but also change 8 components in the Rec/Play section to allow
for the lower data rate (250kbit, not 500kbit as it was designed for) and also
change the Recording Current to allow for the low data rate/rev speed!

Hopefully this should sort it all out .... not bad for 9 quid (normally 32 
quid and upwards ....)

The drive is a JVC MDP series drive ...

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
document_id: 53900
From: einari@rhi.hi.is (Einar Indridason)
Subject: Re: How to the disks copy protected.

In <1993Apr21.085848.12704W@lumina.edb.tih.no> ketil@edb.tih.no (Ketil Albertsen,TIH) writes:

>May we interpret this as an offer to volunteer as editor for a
>"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>an initiative! *I* will volunteer to ask some of the questions, if you will
>provide the answers :-)


Ok, here could be the first question or answer or something:

Q: I want to copyprotect a program I wrote.  How should I do it?
A: You would be wise not to copyprotect that program.  You see, those 
   people that wants to get a cracked copy of your program will go to 
   various length to crack your program, and some of those crackers 
   are good, and know the common tricks.
   So, the copy protection wouldn't stop those.
   Ok, then.  What about legitimate users?  Copy protection can be a hassle
   for legitimate users, and can hinder them in their work, expecially
   if there is some "key" item that can get lost.
   So, the copy protection wouldn't help much of the legitimate users, but
   would make life somewhat of a misery for them.



(This is my opinion, and I speak as a legitimate user :-)
You are of course free to have your opinion about this subject....



--
einari@rhi.hi.is

Newsgroup: sci.electronics
document_id: 53901
From: lgardi@uwovax.uwo.ca
Subject: Re: Long distance IR detection

In article <1993Apr20.183416.18744@dres.dnd.ca>, sburton@dres.dnd.ca (Stan Burton) writes:
> 
> --
> 
> I would like to be able to detect the angular position (low accuracy) of an
> IR emitting source at a distance of about 100 meters (more is better) in
> daylight.  The IR source could be emitting a signature; I'm leaning toward
> 30 KHz square wave with 50% duty cycle.
> 
> I am considering the use of a quadrant detector from Centronic Inc. to give
> information to a pan/tilt head to point the sensor and thus determine the
> angles.  For the source I am considering wazing the heck out of an IR LED(s),
> possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
> current pulses.  At this current the duty cycle of the LED drops to 10% and I
> would need to cycle five of them in turn to get the 50% required.
> 
> Has anyone done something like this?
>
Why don't you just run one LED at 60 KHz and use a flip flop at the receiving
end to divide by 2 and give you a good square 30KHz signal.
Just a thought.
LORI
 
> Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
> (403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6
-- 
<<<RED FISHY WINS>>>
Lori Gardi				(519) 661-2111 ext 8695
Dept. of Astronomy,			lgardi@uwovax.uwo.ca
University of Western Ontario
London, ON, CANADA, N6A 3K7

Newsgroup: sci.electronics
document_id: 53902
From: leblanc@cvm.msu.edu (Pat Leblanc)
Subject: wireless data transfer

I am involved with a Michigan company that has an application requiring 
wireless data transfer.  If you have expertise or information that may 
assist us in this project, please contact me (INTERNET: leblanc@cvm.msu.
edu).


Newsgroup: sci.electronics
document_id: 53903
From: hcb@netcom.com (H. C. Bowman)
Subject: 8x oversampling CD player


Hello--

I just bought a new portable CD player for the office, and I notice that
it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
I understand what oversampling is (the rate of discrete "samples"
exceeds the highest frequency component of interest by some factor),
I don't understand this "8 TIMES" business...  It seems to me that when
I bought my first CD player (was it REALLY 10 years ago?!), the specs
said "4 TIMES" ...  Could someone please tell me whether I'm getting
senile?  If I'm not, then what good does it do for the player to take
samples at a higher rate?  If I really wanted better fidelity, wouldn't
I have to have the same higher rate of sampling during the recording
process?  Furthermore, am I wrong in interpreting the sampling rate
(from the player's point of view) as being the same thing as the data
rate for the bit stream coming off the optical medium?  Does this mean
that the data rate (related to the rotational speed of the disk) has 
changed since 1983?

I'm so confused...  

--Cliff

-- 
| Clifford Bowman, Box 1890, Russellville, AR  72811 | hcb@netcom.com |
| I'm pretty sure the world *isn't* fair...  If it   | (501) 968-2232 |
| were, I'd be a lot worse off!                      |      N5TJU     |

Newsgroup: sci.electronics
document_id: 53904
From: edhall@rand.org (Ed Hall)
Subject: Re: Los Angeles Freeway traffic reports

In article <C5uLqn.Gpw@fc.hp.com> cfb@fc.hp.com (Charlie Brett) writes:
>: While driving through the middle of nowhere, I picked up [KNX], AM 1070,
>: a clear-channel station based in Los Angeles. They had an ad 
>: claiming that they were able to get traffic flow information from 
>: all of the thousands of traffic sensors that CalTrans has placed
>: under the pavement. Does CalTrans sell this info? Does [KNX] have
>: an exclusive? What's the deal?

Well, they claim they are the only radio broadcaster with this
information.  But the city's cable channel (35 in CableVision areas)
shows this information map during travel times (6-9am and 4-7pm, I
believe).  Most of the major LA freeways are covered.  The
computer-generated map shows green, yellow, red, or flashing red
(respectively: <40mph, 25-40mph, >25mph, and "incident"--I might be off
a little on the speeds, since this is from memory).

I often look at this display in the morning to see if I really want to
fight the traffic on the Sepulveda Pass or work from home for a little
while to wait for it to clear.

Another poster explained the origin of the information: sensors (embedded
wire loops) in the pavement near ramps and every half mile or so.  CalTrans
has had a "big board" driven from this data in their traffic control center
for some time.  I don't know if they are selling the data or if anyone
with the equipment necessary for its transmission and display can have
it.

		-Ed Hall
		edhall@rand.org

Newsgroup: sci.electronics
document_id: 53905
From: jimmy@fireflare (Jimmy Mosquera)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In article <C5GE69.Lo0@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>Almost any two dissimilar metals in almost any electrically conductive
>liquid.
>
>Example: Copper and zinc in Coca-Cola...
>
>copper and galvanized steel nails in a lemon...
>
>Don't expect much power out, but it should be easily detectable
>with a voltmeter.
>
>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><



A copper and a zinc rod in a potato also work nice.



Newsgroup: sci.electronics
document_id: 53906
From: martyj@mrcnext.cso.uiuc.edu (martin johnson)
Subject: Hi Volt from battery

I need a small battery powered hi voltage capacitive discharge supply to
deliver ~6 joules at 250 volts. This implies a 200uf cap. I have built
a very satisfactorily operating version from a MAX641, but do not like
the idea of using a $6 single source part. It seems that the ubiquitous
camera flash circuit is what I want, but I cant get mine apart without
breaking it. I would appreciate receiving the circuit description or
a source of one. I have already looked in several electronics circuits
handbooks to no avail. Thanx
--
______________________________________________
|  martin johnson      martyj@uiuc.edu       |
|  "mind your business", on first US coin    |
|____________________________________________|

Newsgroup: sci.electronics
document_id: 53907
From: acm@Sun.COM (Andrew MacRae)
Subject: Re: arcade style buttons and joysticks

In article <1993Apr21.024036.7394@lynx.dac.northeastern.edu>, dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:
 > Hi there,
 > Can anyone tell me where it is possible to purchase controls found
 > on most arcade style games.  Many projects I am working on would
 > be greatly augmented if I could implement them.  Thanx in advance.


HAP controls just outside Chicago sells these.  I don't remember which
suburb they are in.  The prices are pretty reasonable and they are
easy to hook up.  I bought a new coin mechanism from them for $25.00
a couple of years ago.

						Andrew MacRae
						

Newsgroup: sci.electronics
document_id: 53909
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>I built a little project using the radio shack 5vdc relays to switch
>audio.  I got pretty bad 'clicks' when the thing switched. 

>	Is there a good relay/relay circuit that I can use for switching
>audio, so that there will be *NO* noise of any kind on the audio lines.

	With relays alone, you will always get a transient when
you abruptly turn ON or OFF any channel.  If you don't want to hear
the transient, use some other device (a photoresistor-output optoisolator
is the usual sort of thing) to gently MUTE the signal, then switch,
THEN remove the power from the lamp in the optoisolator.

	It used to be standard practice to employ photoresistors
in switching audio, because the photoresistor time delay (a few
thousandths of a second) kept any noise in the digital side (which
drives the lamp) from contaminating the audio.  And, the devices
are cheaper than relays.

	John Whitmore

Newsgroup: sci.electronics
document_id: 53910
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
>Brian Day (bday@lambda.msfc.nasa.gov) wrote:
>: On December 29, 1992, it was illegal to operate a radar detector
>: in the state of Virginia.  If one got caught, one got fined $65.00.

>The Federal Communications Act of 1934 made it *legal* for you to
>operate a radio receiver of any kind, on any frequency (including
>X, K, and Ka bands) in the United States. 

	And the Commonwealth of Virginia has not exactly butted
against the issue on those grounds.  The claim is that AS A MATTER
OF TRAFFIC SAFETY one is not allowed to have a functioning radar
detector on the dashboard while operating a motor vehicle.

	Yes, the argument is bogus, BUT... it hasn't been successfully
challenged in court.  Yet.

	John Whitmore

Newsgroup: sci.electronics
document_id: 53911
From: jbore@cosmos.shearson.com (Joe Bore)
Subject: Re: Need to find out number to a phone line



try finding a friend that has caller id, then give him a call...

jb


In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:

   Path: shearson.com!uupsi!psinntp!uunet!haven.umd.edu!darwin.sura.net!newsserver.jvnc.net!howland.reston.ans.net!noc.near.net!nic.umass.edu!risky.ecs.umass.edu!umaecs!alee
   From: alee@ecs.umass.edu
   Newsgroups: sci.electronics
   Date: 18 Apr 93 15:04:10 GMT
   Lines: 13


   Greetings!

	   Situation:  I have a phone jack mounted on a wall.  I don't
		       know the number of the line.  And I don't want
		       to call up the operator to place a trace on it.

	   Question:   Is there a certain device out there that I can
		       use to find out the number to the line?
	   Thanks for any response.
						       Al


--
-------------------------------------------------------------------------------
Joe Bore					 | "Life is Short...Code Hard"
jbore@Shearson.COM | ...!uunet!shearson.com!jbore| 
(212)464-3431, Beeper:  (212)396-4248		 |

Newsgroup: sci.electronics
document_id: 53912
Subject: Re: Power, signal surges in home...
From: emd@ham.almanac.bc.ca

vanderby@mprgate.mpr.ca (David Vanderbyl) writes:

> drand@spinner.osf.org (Douglas S. Rand) writes:
> 
> >   Hams can legally run up to 1500 watts.  It is very unlikely, however,
> >   that a ham would be running that kind of power from a car.
> >
> >Not possible either.  You'd need about a 300 amp alternator for
> >just the amplifier.
> 
> It is too possible.  As the original poster said "it is very unlikely"
> but definately possible.  (Can you say batteries?)


I've even seen pictures of an installation where the ham pulled a little 
trailer behind his car with a 4KW generator, and ran the full legal limit 
while mobile. I don't know what his gas mileage was like, though, or 
where he found resonators able to stand the gaff.


emd@ham.almanac.bc.ca (Robert Smits Ladysmith BC)

Newsgroup: sci.electronics
document_id: 53913
From: tom@afthree.as.arizona.edu (Thomas J. Trebisky)
Subject: Re: A question about 120VAC outlet wiring..

crichmon@sedona.intel.com (Chris Richmond) writes:
>Well, my house was built just last year, and the breaker box is wired the
>same way.  All the white and ground wires are on a common bus.  Except for
>the 220V circuits, only black wires are hooked to the breakers.  It was
>the same way in the last two houses I had also.  Are you sure this is wrong?
>I still have the building inspector's signature on the breaker box.

The point is that the original poster was talking about connecting
ground and neutral in the *outlet* box (big NO NO), and you are talking
about them being connected in the breaker box (as things should be).

If this is not obvious, the point is that there should be current
flow in the white, i.e. neutral/return wires when things in the
house are operating.  There should not be any flow in the ground wires
unless there is a fault condition.  Notice also that in the breaker box
there is a wire leading from the above-mentioned junction to earth ground,
usually a pipe or spike driven into the ground.
-- 
	Tom Trebisky	ttrebisky@as.arizona.edu

Newsgroup: sci.electronics
document_id: 53914
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: 8x oversampling CD player

In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>
>Hello--
>
>I just bought a new portable CD player for the office, and I notice that
>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>I understand what oversampling is (the rate of discrete "samples"
>exceeds the highest frequency component of interest by some factor),
>I don't understand this "8 TIMES" business...  It seems to me that when
>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>senile?  If I'm not, then what good does it do for the player to take
>samples at a higher rate?  If I really wanted better fidelity, wouldn't
>I have to have the same higher rate of sampling during the recording
>process?  Furthermore, am I wrong in interpreting the sampling rate
>(from the player's point of view) as being the same thing as the data
>rate for the bit stream coming off the optical medium?  Does this mean
>that the data rate (related to the rotational speed of the disk) has 
>changed since 1983?

[Note: I just tried to figure this stuff out about a month ago myself, from
various people on the net, so I could be wrong.]

The data is only ever read once (barring mistracks and such, of course),
and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
Oversampling takes two discrete data points, and interpolates n-1 points
between them for n times oversampling.  When I asked, people said that the
interpolation was not simply linear interpolation, but significantly more
complicated.

Anyway, then, the purpose of oversampling is to move the "effective"
sampling rate up to n times 44.1 KHz, in order to use higher frequency
antialiasing filters.  For the same quality filter, higher oversampling
lets you build cheaper filters, whereas for the same price filter, higher
oversamplings lets you build better filters.  So, assuming the quality of
all other components in a CD player remained the same, oversampling should
allow a manufacturer to produce _slightly_ better sound due to anti-alias
filtering.

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 53915
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Suggestions  on Audio relays ???

In article <1993Apr20.102756.1709@mala.bc.ca> wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
>In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
>> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>>I built a little project using the radio shack 5vdc relays to switch
>>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>>My question is:
>>>	Is there a good relay/relay circuit that I can use for switching
>>>audio, so that there will be *NO* noise of any kind on the audio lines.
>> 
>> Are you switching high level signals or low level signals like pre-amp
>A novel circuit I used to build was a primitive "optical isolator".. It consists
>of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
>off the cell is high resistance.  Turn the lamp on and the resistance lowers

I use an H11F1   FET optoisolater to switch microphone level signals.
There is no click, since I put a .1uF cap across the LED.  Distortion
measurement are very low with mic level, and they went up to 0.03% at a
+ 14 dB line level.  All I did was put the FET in series with one leg
of the balanced line.  No hums, pops, just audio jumping out of silence.
The FET runs about 100 million ohms with the LED dark and drops to 150-200
ohms with it on.

Hey, it works, and works well.
Galen Watts, KF0YJ


Newsgroup: sci.electronics
document_id: 53916
From: schaefer@imag.imag.fr (Arno Schaefer)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
|> 
|> >	I guess what I am saying is that your question is difficult, if not
|> >impossible, to answer.  What exactly do you want to know?  Do you need a good
|> >one for a project you are working on?  How secure must it be?  Are you trying
|> >to crack one that someone else has used?  I can probably make suggestions,
|> >assuming the activity is strictly legal.  (In general, it is a BAD idea,
|> >legally, to tamper with copy protection.  It can also lead to corruption of
|> >files which you necessarily do not have back ups of (being as they are copy
|> >protected,) which can be devestating.)  Do you have absolutely no ideas for
|> >practical applications, and are merely curious?
|> >	Please clear up those questions, and I'll try to help as much as I
|> >can.
|> 
|> May we interpret this as an offer to volunteer as editor for a
|> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
|> an initiative! *I* will volunteer to ask some of the questions, if you will
|> provide the answers :-)
|> 
|> Ketil Albertsen

Hey, now will you stop encouraging him? Copy protection only serves one pur-
pose: to keep the honest buyer from making (legal) backup copies. It will
definitely not stop any pirates. If you want to protect you soft, supply a
good documentation and support. This is IMHO the *only* way of effectively pro-
tecting software.

Best Regards,

Arno

-- 
--------------------------------------------------------------------------------
Arno Schaefer				ENSIMAG, 2e Annee
Email: schaefer@silene.imag.fr
Tel.: (33) 76 51 79 95			:-)
------- No, you're not paranoid - the world is really out to get you -----------

Newsgroup: sci.electronics
document_id: 53917
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: arcade style buttons and joysticks

In article <1993Apr21.024036.7394@lynx.dac.northeastern.edu> dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:
>Subject: arcade style buttons and joysticks
>Can anyone tell me where it is possible to purchase controls found
>on most arcade style games.  Many projects I am working on would

What about the common joystick found in all computer shops?

- gerrit

Newsgroup: sci.electronics
document_id: 53918
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Beginner's RF ???

In article <C5sr8H.JpH@cbnewsl.cb.att.com> klink@cbnewsl.cb.att.com (steven.r.klinkner) writes:
>Can anybody recommend a good, application-oriented beginner's reference
>to RF circuits?  
>Steve Klinkner                AT&T Bell Labs               srk@boeing.att.com

I have the ARRL Handbook for the Radio AMateur, and I'm getting the
Solid STate Design for the Radio Amateur.

The handbook is $25 and Solid State is $12 from ARRL, 225 Main, Newington,
CT 06111 but you should be able to find them at electronics or amateur radio
stores.
ARRL will want $5 or so for shipping.
Good Luck,
Galen Watts, KF0YJ



Newsgroup: sci.electronics
document_id: 53919
From: henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley)
Subject: Re: 68HC16 public domain software?

In article <murashiea.15@mail.beckman.com>  writes:
> Does anyone know of an FTP site where I might find public
> domain software for the Motorola 68HC16 microprocessor?
> I am looking for a basic interpreter/compilier or a 'C'
> compiler.  Thanks in advance.
> 					Ed Murashie
Yep, at:
oak.oakland.edu
they have a couple different 68HC16 things in
/pub/msdos/emulators
and get the file
00-index.txt
for a list of what they have.
lige

Newsgroup: sci.electronics
document_id: 53920
From: Daniel.J.Stern@dartmouth.edu (Daniel J. Stern)
Subject: Seeking info on wear on monitors 

We are Dartmouth engineering students.We are looking for documented
data regarding the wear associated with turning on an off a monitor and
how it relates to power consumption.  Interested in a comparison
between the wear on a monitor which is left on continuously and one
which is turned off when not in use.  

Please personalize E-mail to: ds@Dartmouth.edu

Thank you,

Dan Stern
Oliver Weir

Newsgroup: sci.electronics
document_id: 53921
From: exuptr@exu.ericsson.se (Patrick Taylor, The Sounding Board)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.131908.29582@uhura.neoucom.edu> wtm@uhura.neoucom.edu (Bill Mayhew) writes:
>From: wtm@uhura.neoucom.edu (Bill Mayhew)
>Subject: Re: How to the disks copy protected.
>Date: Wed, 21 Apr 1993 13:19:08 GMT

>Write a good manual to go with the software.  The hassle of
>photocopying the manual is offset by simplicity of purchasing
>the package for only $15.  Also, consider offering an inexpensive
>but attractive perc for registered users.  For instance, a coffee
>mug.  You could produce and mail the incentive for a couple of
>dollars, so consider pricing the product at $17.95.

Or, _documentation_ for the program ;-).  A lot of shareware out there is 
very similar in the approach - send in your money, and you get 
documentation, and a free upgrade to the latest version.  Perhaps even 
support of some small degree.  Whatever you want to offer that is "better" 
than the circulating version.

>You're lucky if only 20% of the instances of your program in use
>are non-licensed users.

Figure about 50%, as I have seen.

>The best approach is to estimate your loss and accomodate that into
>your price structure.  Sure it hurts legitimate users, but too bad.

It doesn't really hurt legit users.  Shareware is still much cheaper than 
the alternatives.

 ----------------------------------------------------------------------------
 ---------Visit the SOUNDING BOARD BBS +1 214 596 2915, a Wildcat! BBS-------

 ObDis: All opinions are specifically disclaimed. No one is responsible.

    Patrick Taylor, Ericsson Network Systems  THX-1138
    exuptr@exu.ericsson.se                    "Don't let the .se fool you"

Newsgroup: sci.electronics
document_id: 53922
From: henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley)
Subject: Re: what to do with old 256k SIMMs?

In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason  
Haines) writes:
> 
> 	I was wondering if people had any good uses for old
> 256k SIMMs.  I have a bunch of them for the Apple Mac
> and I know lots of other people do to.  I have tried to
> sell them but have gotten NO interest.
> 
> 	So, if you have an inovative use (or want to buy
> some SIMMs  8-) )
Sure I'll give you 10 bucks for all of them

Newsgroup: sci.electronics
document_id: 53923
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: _Exhausted student needing HELP!

 
      Well, I've now been working on this DAMNED stepper controller board
 since 9pm.  It's now 6am... I'm pissed off.  Period.  Alright, I can
 drive the steppers through the 3479P's; no problem (that's with the
 6-wire steppers, 2 to +, and the other 4 are the phase lines).  Problem
 1:  I've got some 4 wire steppers.  I put the darkest line to + and the
 other 3 to the 3479P... worked, kinda.  Tried it with a printer stepper
 (moves the head back and forth, 4 wires), didn't work too well.  It 
would
 shift back and forth (use something like a 4017 instead?)  Also I've 
been
 trying to get a bunch of NPN's to work with it... NO LUCK... tried 
PNP's,
 still NO LUCK!!!  I don't know if I'm cursed on this or what, but I feel
 my brain slowly frying with the thought of STEPPER ... ARGGG!!!
         I don't know what's wrong with the transistor hook-up (to-220 
pkg
 type), also tryed the 2n2222-pkg type... no luck.

                         I'm going to try getting some z's, and I hope 
you
 can help me with this problem.
   If someone can please help me with this soon, it would be greatly
   appreciated...

                 Thanks.




 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 
l

Newsgroup: sci.electronics
document_id: 53924
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Circuit Cellar Ink address?

In article <1qvlmaINNhuu@shelley.u.washington.edu>,
ptorre@hardy.u.washington.edu (Phil Torre) wrote:
> 
> Is CCI still published?  If so, does anyone have their address?


Circuit Cellar Inc.
4 Park St.  Suite 20
Vernon, CT  06066
(203)875-2751

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
document_id: 53925
From: klink@cbnewsl.cb.att.com (steven.r.klinkner)
Subject: Beginner's RF ???

Can anybody recommend a good, application-oriented beginner's reference
to RF circuits?  

I am pretty good on theory & know what different types of modulation mean, 
but don't have a lot of practical experience.  A book detailing working
circuits of different types (modulation, power, frequency, what is legal,
what is not, et cetera), would be very helpful.

Thanks.

-----------------------------------------------------------------------------
Steve Klinkner                AT&T Bell Labs               srk@boeing.att.com
                                                           att!boeing!srk    
-----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53926
From: jam@ameslab.gov (Jerry Musselman)
Subject: UART needed

I need to find a UART that will interface to an 8051 and do the following:
	-250k baud, 8 data bits, 2 stop bits, no parity
	-ability to do BREAK detect (IRQ or output pin)
	-IRQ on character received

I'm using a Dallas DS2250 at 16 Mhz (8051 clone), but it won't do 
break detect.  I've looked at the 6850, 8251, 7201, 2661, etc...

	Any help would be appriciated!!!

Newsgroup: sci.electronics
document_id: 53927
From: rg@futserv.austin.ibm.com (R.G. Keen)
Subject: EICO tube tester repairs? 

I had the good luck to obtain an EICO dynamic conductance 
tube tester for a song. Unfortunately, I was a little out of
key; the only thing wrong with it was an open meter movement.
Does anyone know where I can find either another meter movement
like it, a dead-but-not-the-meter-dead unit, or schematics 
to specify the current scale of the meter movement? I can cut
and paste a more sensitive movement in if I can find what the
full scale current was. Or... is EICO still contactable?

The thing is a model 666 -nope, not a joke or any sort of snide
reference.

R.G.


Newsgroup: sci.electronics
document_id: 53928
From: uli@izfm.uni-stuttgart.de (Uli Allgeier)
Subject: Re: PADS Question - How do I go from a schematic -> PCB?

Hi!
In article <C5svup.I4I@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:

>After I have produced a schematic with PADS-LOGIC, how do I import it into 
>PADS-PCB to create a PCB pattern?  The only way I've gotten it to work is
>to output a FutureNet netlist, and then import this into PADS-PCB.  Is there
>another way of doing this?  I didn't see any information in the instructions
>provided, but I might have missed something.  Any suggestions would be 
>greatly appreciated.  Thanks!

Sorry, it's german, but I hope you understand it.


Uebertragung der Schaltplan-Daten (*.SCH) in die Board-Daten
(*.JOB):

PADS-LOGIC:
         In/Out
         Reports
         Net List
         Select      PADS-PCB
Net List Output file name
         -> filename angeben

PADS-PCB:
         In/Out
         Ascii In
Ascii input file name
         -> filename angeben
Errors aoutput file name
         -> filename angeben, nicht CR

Jetzt sind alle Bauteile auf einem Haufen und muessen mit Move
verteilt werden.

Viele Gruesse

Uli

Newsgroup: sci.electronics
document_id: 53929
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In article <1993Apr19.185326.9830@Princeton.EDU> mg@cs.princeton.edu (Michael Golan) writes:
>The board itself is also identical, with room for all three caps. The
>US/Can versions is clearly indicated in both places.
>
>How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
>(there are just standard caps, no special W/type/precision). 

This may be a safety issue; the CSA is more paranoid in certain areas than
UL and such.  Two caps in series means that you don't have a short if one
of them shorts.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53931
From: camter28@astro.ocis.temple.edu (Carter Ames)
Subject: Lead Acid batteries & Concrete?


   I was just wondering one thing, actually two. ( I hope that this is the
proper place to post this subject)

  Why does a lead acid battery discharge and become dead (totally unuseable)
when stored on a concrete floor?  
  I decided to bring the battery in from the lawn mower and the motorcycle
from the unheated garage this year, *to preserve them* and I just
went to use them and noticed that not only do they not work, but 
they act like the two terminals are shorted.  I asked a friend
and he said that you should never do that, 'cause it ruins them,
but he couldn't tell me why.

thanks
camter28@astro.ocis.temple.edu

Newsgroup: sci.electronics
document_id: 53932
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR remote control receiver

ab616@Freenet.carleton.ca (Marc Dion) writes:


>For a project of my own, I would like to build a Infra-Red Remote control
>receiver (for regular VCRs and TVs remotes).  Does anybody have any info
>or tips on how to build such receiver ?
>In particular,
>a) which photo detector should I use (which wavelength do remotes use) ?
>b) which ICs or circuit should I use ?
>c) any suggestions for circuit layout

>Please reply to this group (if you wish), but as well via e-mail (my
>link to usenet is not always available).

	I'd like to see this info as well.  As for wavelength, I think
you're primarily going to find two - 880 nM +/- a bit, and/or 950 nM
+/- a bit.  Usually it is about 10 nM either way.  The two most common
I have seen were 880 and 950 but I have also heard of 890 and 940.
I'm not sure that the 10 nM one way or another will make a great deal of
difference.

	Another suggestion - find a brand of TV that uses an IR remote,
and go look at the SAMS photofact for it.  You can often find some very
detailed schematics and parts list for not only the receiver but the
transmitter as well, including carrier freq. specs. and tone decoding
specs. if the system uses that.

Duane


Newsgroup: sci.electronics
document_id: 53934
From: philc@macs.ee.mcgill.ca (Phil Crawley)
Subject: Read only if going to ISCAS93 in Chicago


   This is message is only of interest to those going to 
International Symposium on Circuits and Systems that is being
held in Chicago this May.
   
   I checking to see if there is any people out there who would be
interested in getting together for a pickup game of soccer during 
the off hours of the conference. If so could you e-mail me at:

philc@macs.ee.mcgill.ca

I'll bring a ball. If you know someone who is going to the 
conference and you know that they are avid soccer players
please pass on this message to them. Also if someone in
Chicago is going to the conference please let me know if
there is any field near the hotel where we can play.

Thanks. Bye.

Philip Crawley 

Newsgroup: sci.electronics
document_id: 53935
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: HELP: MC146818A Real Time Clock Standby Mode

In article <1r0b69INN5ct@flash.pax.tpa.com.au> mgregory@flash.pax.tpa.com.au (Martin John Gregory) writes:
>I am having trouble obtaining the specified standby current drain from
>a MC146818A Real Time Clock...
>lowest current drain I can acheive at 3.7V Vcc is 150uA.  This is
>three times the specified MAXIMUM...
>1) Made sure that RESET/ is asserted for Trlh after powerup, and AS is
>   low during this time.
>2) Made sure that there is a cycle on AS after the negation of RD/ or
>   WR/ during which STBY/ was asserted...

Are any of the inputs to the chip coming from TTL?  Standby-drain specs
for CMOS chips typically apply only if inputs are pulled all the way down
to zero or all the way up to Vcc.  TTL isn't good at doing the former and
it won't do the latter at all without help from pullup resistors.  This
sort of thing can easily multiply power consumption by a considerable
factor, because the CMOS transistors that are supposed to be OFF aren't
all the way hard OFF.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 53936
From: pyeatt@Texaco.com (Larry D. Pyeatt)
Subject: Membrane keypad with custom legend.

I had a catalog with membrane keypads, but I dunno what
happened to it, and it was so long ago that I forget the
name of the company.  Anyway, you could make your own
legend and slip it behind the bezel.  Really nice and 
reasonably priced.  Can anyone tell me where to get some
more of these critters?  I've tried several places, but
none of them seem to have keypads which allow you to use
your own legend.

Any suggestion would be appreciated.

-- 
Larry D. Pyeatt                 The views expressed here are not
Internet : pyeatt@texaco.com    those of my employer or of anyone
Voice    : (713) 975-4056       that I know of with the possible
                                exception of myself.

Newsgroup: sci.electronics
document_id: 53937
From: dclaar@cup.hp.com (Doug Claar)
Subject: Los Angeles Freeway traffic reports


oops, that's KNX 1070. KNBR is up in 'Frisco, and down at 680.

==Doug "San Fran can't be 'the city': Jack Webb told me so" Claar

Newsgroup: sci.electronics
document_id: 53938
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: Long distance IR detection

sburton@dres.dnd.ca (Stan Burton) writes:

>I would like to be able to detect the angular position (low accuracy) of an
>IR emitting source at a distance of about 100 meters (more is better) in
>daylight.  The IR source could be emitting a signature; I'm leaning toward
>30 KHz square wave with 50% duty cycle.

>I am considering the use of a quadrant detector from Centronic Inc. to give
>information to a pan/tilt head to point the sensor and thus determine the
>angles.  For the source I am considering wazing the heck out of an IR LED(s),
>possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
>current pulses.  At this current the duty cycle of the LED drops to 10% and I
>would need to cycle five of them in turn to get the 50% required.

>Has anyone done something like this?


	Yeesh, you WILL be nailing those IRLEDs.  May I suggest getting your
mitts on the Siemens SFH484-2 IRLED?  This unit is designed to take some big
current pulses if you can get your duty cycle down a bit.  It will output
nearly a watt (975 mW) with REAL short duty cycle times.

(nice thing about the SFH484-2 is that it is CHEAP.  I got mine for about
50 cents a piece, even though I had to buy 100 of them....)

	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
6 WATTS.  I don't have the book here at work so I can't recall the company
name.  The 6 watter ain't cheap, around $108 but if you want some power,
mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
1 watt device in their line, and will sell small quan. to individuals.
If you are interested, I can find the book at home and get the
pertinent info.

	Now, as for the position detector, you might try ELTEC in Florida.
Phone number listed in the 92/93 ETID is 904-253-5328.  They seem like 
nice people.  Their specialty is passive infrared detection devices,
so they might be able to help you out.

	I'm curious about your applications if you don't mind saying.
The device sounds like it could be useful in a lasertag game, although you'd
need to up your carrier signal concept to 58.8 KHz......

Duane


Newsgroup: sci.electronics
document_id: 53939
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Answers to many electronics Questions

I have notice a lot of electronics questions by people who are obviously not 
"tuned-in" to electronics.  Many of them have rather simple answers, and 
many of them require a circuit diagram.

Rather than muck up the network, why don't you write to me, send a self-
addressed, stamped envelop, and I'll answer your questions, if I can.

W. L. Willis, P. E.
114 Fern Circle
Clemson, SC 29631

Newsgroup: sci.electronics
document_id: 53940
From: paula@nlbbs.com (Paula Stockholm)
Subject: Re: Need to find out number to a phone line

 In most areas of the country, serviced by ESS (or CESS), your phone
--

      * * * * * * * * * * * * * * * * * * * * * * * * * * *
      *               paula@nlbbs.com                     *
      *  Paula Stockholm            Cumberland, Maine USA *
      * * * * * * * * * * * * * * * * * * * * * * * * * * *

Newsgroup: sci.electronics
document_id: 53941
From: kn1@cunixa.cc.columbia.edu (Kimball Ng)
Subject: Re: Laser vs Bubblejet?

kolstad@cae.wisc.edu (Joel Kolstad) writes:

>One other thing... there are bubblejets, and then there are BubbleJets.
>There are a few bubblejets out there that produce rather mediocre output
>(such as HP's dinky little BubbleJet), whereas most produce really good
>looking output (such as HP's DeskJets).  IBM and Canon both produce some of
>the really good style bubblejets.

>P.S. -- If you're in the market for a portable bubblejet printer, I can
>highly recommend the HP Portable DeskJet, although I've heard the portable
>Canons are good too (I needed PCL support, myself).  With the DeskJet
>Portable, you even get an undocumented PCMCIA card slot!

I second that suggestion.  Although I don't own the HP Portable Deskjet,
I *do* own the HP Deskjet 500.  It gives the nicest outputs, with only
a minor loss of quality.   For all intensive purposes (papers, letters,
resumes), I treat my Deskjet like a laser printer (You *do* have to
look a bit closely to see the blurs in the characters).  Only one
grudge, the ink that HP gives you does smudge rather quickly in the
presence of moisture (Even though the ink is waterproof).  However,
you would have to spend about $500 more for laser quality.

The cannon bubblejets are nice, however they don't seem to have as
much support (eg: drivers for popular programs) as the HP ink-jets.
Also HP Deskjet (regular,plus,500,500c) accepts xerox paper (I believe
that the cut-sheet feeder is an option for the cannon bubblejet).

If you don't mind refilling your printer with cheap ink (say
fountain-pen ink), then the HP deskjets are *very* cheap to maintain
(I paid $3.50 for my last bottle of ink and I expect it to last 9
months). 

	-Kimball (who doesn't work for HP, but just loves his printer
		  very much!)

PS: I have a question for you netters, I'm too afraid to refill with
the waterproof inks they sell in art-supply houses because I had brought
a bottle of waterproof ink and it clogged up my cartridge. I
wonder what is a 'good' waterproof ink (aside from buying refill-kits)
to refill my cartridge?





Newsgroup: sci.electronics
document_id: 53942
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Re: CAD Program for Electronics?

In article <1993Apr17.211126.23467@norfolk.vak12ed.edu> fculpepp@norfolk.vak12ed.edu (Fred W. Culpepper) writes:
>I am making a search for a CAD program that does a decent job
>of making schematic drawings.  The program needs to be in
>MS-DOS, Windows if possible.
>
>What I want the CAD program to do is to draw diagrams by
>dragging elements onto the screen, and in this the elements
>needed are as diverse as vacuum tubes to ICs (case with pins).
>It also needs to have provision for adding legends to the
>components as well as their values.  In other words I want to
>produce quality drawings.  Printout would be to either 24 pin
>dot-matrix and/or Laser Printer.

I would suggest Draw for Windows (by Micrografx).  I have this on my
home box.  Its quite impressive and only cost UKL100.  It has a rather
nice clip-art library facility which you can expand with your own
drawings.  There is no circuit component clip-art included, but you
could add your own quite easily.

It works with any Windows printer driver of course, and can also
export embedded postscript and PCX files.

Note: I am not connected with Micrografx in any way.

Paul.
-- 
Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
document_id: 53943
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: help - how to constru

>Dean Anneser (anneser@pwa-b.uucp) wrote:
>: My 9 yr old son has signed up to do a science report on batteries.  I was
>: wondering if anyone could provide me with some information as to how to
>: construct a home-built battery.  In my grade school days, I remember seei
>: the 'ice cube tray' version, but I don't remember what to use as a good
>: electrolyte or what the easily obtainable metals were.
>:
>: Thank you in advance.

>I remember watching a whole "Mr. Wizzard" program on this subject when
>I was a kid.  The battery constructed on the program which made the
>biggest impression on me, and generated the most power, was made using
>a galvanized bucket (for the zinc) and a copper toilet tank float.  The
>electrolyte was sauerkraut!

Take a lemon.  Stick a copper strip into the lemon.  Stick a galvanized
nail in about 1 to 1-1/2 inches from the copper strip.  You should get
about 1/2 volt from it - enough to light an LED.


 * SLMR 2.1 * Support your medical examiner, die strangely.
                     
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
document_id: 53944
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Food Dehydrators

>Does anybody out there have one of those food dehydrators I've been seeing
>all over late-night TV recently? I was wondering if they use forced air, hea
>or both. If there's heat involved, anybody know what temperature they run at
>My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
>and a heater. Seems to me you should be able to throw a dehydrator together
>for just a few bucks. Heck, the technology is only what? 1,000 years old?

You can learn how to build a deyhdrator very easily from the book, "The
Hungry Hiker's Guide to Good Food," by Gretchen McHugh.  The heat source
is a 100 watt light bulb.  Basically, it's a vertical wooden box with
ventilation holes in the top and bottom (lots of them, you want the air
to flow).  The light bulb goes in the bottom, and wire cake racks are
spaced every 6" starting about 10" above the bulb.

Or, at a slightly higher cost in electricity, you can do what I do:  Use
your oven.  (NOTE - I do this in an electric oven; some gas ovens may
not have a low enough setting).  Put food to be dried on cookie tins or
racks in the oven.  Set oven to 140 degrees (the lowest setting on my
oven - if yours goes down to 120 that's probably even better.)  Stick a
wooden spoon or something across the front corner of the oven and close
the door on the spoon so that it stays open about an inch - this allows
for airflow.  Leave the stuff in the oven for 6 to 8 hours; check it
often, since this dries it much faster than the dehydrator.  If you are
using cookie sheets instead of racks, turn the stuff over halfway
through.

If you want more info, e-mail me since this isn't really the right sub
for this stuff.

gerald.belton@ozonehole.com


 * SLMR 2.1 * I still miss my boss, but my aim is improving.
                       
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
document_id: 53945
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Need to find out numb

AL>>        Question:   Is there a certain device out there that I can
AL>>                    use to find out the number to the line?
AL>>        Thanks for any response.
AL>>                                                    Al

AL>There is a number you can call which will return a synthesized
AL>voice telling you the number of the line.  Unfortunately, for the
AL>life of me I can't remember what it is. The telephone technicians
AL>use it all the time.  We used to play around with this in our
AL>dorm rooms since there were multiple phone lines running between
AL>rooms.

It probably wouldn't help for you to post the number, since it appears
to be different in each area.  For what it's worth, in the New Orleans
area the number is 998-877-6655 (easy to remember, what?)


 * SLMR 2.1 * Ask me anything: if I don't know, I'll make up something.
                                          
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
document_id: 53946
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: MC SBI mixer

MJM>HI, I was wondering if anyone would be able to help me on twwo related
MJM>subjects. I am currently learning about AM/FM receivers and recieving
MJM>circuits. I understand a lot of things ,but a few things I am confused
MJM>abuot. The first is the MIXER, to mix the RF and local oscillator
MJM>frequencies to make the IF. Does anyone have any cicruit diagrams (as
MJM>simple as possible) for this kind of mixer? I have come across a
MJM>MC-SBL mixer chip But I have not been able to find it in any catalogs
MJM>(ACTIVE,etc...)

MJM>Along the same note, are there any SIMPLE fm receiver circuits anyone
MJM>may have stashed away somewhere and they couold let me see?.

MJM>P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
MJM>ELECTRICAL DIAGRAMS would help a lot.
MJM>I have seen a lot of theory books with no circuits and a lot of
MJM>circuit books with no theory, but one without the other does not help.

Digi-key has the NE-622 chip which has a local oscillator and mixer on
one chip.

For a great combination of theory with actual circuits, the best
reference for non-engineers is probably the Radio Amateur's Handbook
from the ARRL.  Most library's have it in the reference section.


 * SLMR 2.1 * If ignorance is bliss, why aren't there more happy folk?
 
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Newsgroup: sci.electronics
document_id: 53947
From: wayne@uva386.schools.virginia.edu (Tony Wayne)
Subject: Pink Noise

What is Pink noise and how is it used in sound experiments?
-tony
 wayne@uva386.schools.virginia.edu


Newsgroup: sci.electronics
document_id: 53948
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In article <C5uC68.19K@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>
>This may be a safety issue; the CSA is more paranoid in certain areas than
>UL and such.  Two caps in series means that you don't have a short if one
>of them shorts.

Not necessarily true; a short in one, if near the maximum series
voltage drop, will overvoltage the other one and short it too, more
-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
document_id: 53949
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: Membrane keypad with custom legend.

In article <1993Apr21.125530.18387@texhrc.uucp> pyeatt@Texaco.com (Larry D. Pyeatt) writes:
>I had a catalog with membrane keypads, but I dunno what
>happened to it, and it was so long ago that I forget the
>name of the company.  Anyway, you could make your own
>legend and slip it behind the bezel.  Really nice and 
>reasonably priced.  Can anyone tell me where to get some
>more of these critters?

For some reason the name Grayhill springs to mind -- saw something
like that in a Grayhill catalog, along with options for custom printed
overlays and a neat little electroluuminescent backing that would make
the whole shebang glow a nice shade of green ..

mighty handy if you're trying to key a door combination in the dark
and don't want to TURN ON THE &%#$!! LIGHT ..

-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
document_id: 53952
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Part MC68SEC811E2


I know what the 68HC811E2 is all about, but I'm trying to figure
out what the 68SEC811E2 is... specifically, what does the SEC
stand for?

----
Dale Ulan   VE6DAU     ulan@ee.ualberta.ca


Newsgroup: sci.electronics
document_id: 53953
From: acooney@netcom.com (Alan Cooney)
Subject: Re: Los Angeles Freeway traffic reports

I live in the San Francisco Bay Area, and word has it that
something similar is on its way here.  Since we apparently
don't have the sensor base you folks have, they're installing
cameras at strategic points along the freeways (initial tests
are going to be in the Santa Clara area I'm told), with the
video being piped into a command center they're building
somewhere in the East Bay.  I'm not sure if frame grabbers or
cheap labor will be used to interpret the data, but large
multi-colored status displays will show the various routes
using different colors to represent the various average speeds
for each stretch of highway.  An announcer will sit in front
of the status 'wall', and will relay continuous verbal traffic
status to those who want to receive it.  They're apparently also
looking into licensing a low-AM frequency to be dedicated to
providing continuous audio from this system.

In the mean time, they'll set up large incandescent display
boards along the test stretch to provide commuters with data
on traffic conditions up ahead.  My understanding is that the
system is subsidized as a pilot program, and information from it
will be available free of charge.  Perhaps the LA system is
similarly free or provided at an obviously subsidized rate (read
"cheap").

We also have the traffic reports that are broadcast on the SAP
audio channel of television channels 2 and 36.  These are verbal
reports, qualified with a identification tone to tell in-vehicle
receivers like the 'Auto Talk' that the information coming next is
applicable to a given area.  In LA, they're probably using some
other TV channels, but the concept is the same.  Try setting your
stereo TV or VCR to receive the SAP audio channel, and go station
jumping to find out which one is broadcasting this information.
I believe this program is also subsidized, making the in-vehicle
receivers cheap to purchase (and without having to incur monthly
fees to use it).  Since the makers of these in-vehicle receivers
don't have to pay for the broadcast (this may not be completely
true), they likely have no investment in keeping the system
up and running when the Cal Trans stuff hits the airwaves.  You
may have a nifty little TV audio receiver in your car, nothing
more, when this happens.  Perhaps a word to the wise...?  ;)

I think we'd all be interested in a summary post if you get more
info on how the LA system is networked and paid for.

Cheers,
Alan
<acooney@netcom.com>


Newsgroup: sci.electronics
document_id: 53954
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: Answers to many electronics Questions

Bill Willis (willisw@willisw.ENG.CLEMSON.edu) wrote:
: I have notice a lot of electronics questions by people who are obviously not 
: "tuned-in" to electronics.  Many of them have rather simple answers, and 
: many of them require a circuit diagram.

: Rather than muck up the network, why don't you write to me, send a self-
: addressed, stamped envelop, and I'll answer your questions, if I can.

: W. L. Willis, P. E.
: 114 Fern Circle
: Clemson, SC 29631

Because the network is quicker, easier, and free (at least to me).

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
document_id: 53955
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: A question about 120VAC outlet wiring.

Dave Martindale (dave@imax.imax.com) wrote:
: They require two separate grounds.  One ground goes to the ground pin
: of the outlet, and the other ground wire is connected to the outlet's
: mounting tabs (and thus grounds the box and faceplate screw and metal
: faceplate, if any).

I thought the ground WAS connected to the metal frame on the socket.

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
document_id: 53956
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: Los Angeles Freeway traffic reports

Charlie Brett (cfb@fc.hp.com) wrote:
: You were right the second time, it is KNX. Believe it or not, I also
: listen to KNX in the evenings here in Colorado! It's kind of fun driving
: through the country listening to traffic jams on the 405. Back to your
: original question. Yes, there are sensors just past every on-ramp and
: off-ramp on the freeways. They're the same sensors used at most stoplights
: now (coils in the pavement). You might want to give CalTrans a call or
: even ask Bill Keene (KNX's traffic reporter). I doubt if just anyone can
: get the information, but it would be worth asking just in case you can
: get it.

I seem to remember that they sell the information (and a computer connection)
to anyone willing to pay.

On the subject of the pavement sensors, can anyone tell me more about them?

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
document_id: 53957
From: acollins@uclink.berkeley.edu (Andy Collins)
Subject: Voltage regulation and current limiting

One not-so-quick question to throw out there for you guys...

For our class project, we need to design and build a power supply
to the following specs:

Voltatge:  adjustable from 1-12V
Current:   *limited* at 1A

Voltage must stay within 2% of designated value for I from 0-1A
AC ripple less than 5 mV (rms)

Of course, we can't just use an adjustable voltage, current-limiting
regulator chip ;^)

Our problem is with the current limiting (i.e. we've found stuff to
do the rest of the parts of the circuit).  What the supply must do,
if presented with a load which would draw more than 1A, given the
supply voltage, is reduce the voltage so that the current will equal
one amp.  Thus, if we were to short the thing with the ammeter, we
should read one amp.  If we measure the current through a 1 ohm 
resistor at 12V, we should read one amp (and the output voltage, by
necessity, must be 1V.

The only basic idea we have seen for the current limiter involves
a circuit which will pull current off of the base of the output 
power transistor, and therefore reduce the output.

So, does anybody have any ideas we could work from?

Thanks in advance.

Andy Collins, KC6YEY
acollins@uclink.berkeley.edu

ps: If anybody wants to flame this as a stupid project, I agree fully,
    but I still have to do it, its graded ;^)


Newsgroup: sci.electronics
document_id: 53958
From: acooney@netcom.com (Alan Cooney)
Subject: Re: Membrane keypad with custom legend.

Try the folks at Dimolex Corp., La Crescenta, CA 91214.
Their number is (818) 957-7001.  They make membrane keypads
that are very flat, in layouts from 2 to 128 keys.  They
have standard models, tactile models (with stainless domes
under each key to make a 'click' you can feel), as well as
backlit models.  Some of them can even be cut with scissors
to form a funky shape other than a rectangle.  Many of the
models are available in a 'kit' which includes a bezel,
colored and plain key covers, and rub on lettering to make
your own layout.  One piece prices aren't cheap, though,
as they want $10 for one four position pad *kit*, and $45
for a 40 position *kit*.

I have no affiliation with Dimolex or any company connected
with them.  I *have* purchased a couple of keypads from them,
and am pleased with what I got.

Cheers,
Alan
<acooney@netcom.com>


Newsgroup: sci.electronics
document_id: 53959
From: DRAMALECKI@ELECTRICAL.watstar.uwaterloo.ca (David Malecki)
Subject: Re: Building a UV flashlight

In article <C5r6Lz.n25@panix.com> jhawk@panix.com (John Hawkinson) writes:
>My main question is the bulb: where can I get UV bulbs? Do they
>need a lot of power? etc., etc.

I've seen them in surplus stores.  All they are are fluorescent bulbs 
without the phosphor, and a UV transparent bulb (special glass).  I've
also seen incandescent versions that you screw into an ordinary 120VAC
socket, probably not what you want.

>
>I'm not too concerned with whether it's long-wave or short-wave
>(but hey, if anyone has a cheap source of bulbs, I'll take both).
>
>One other thing: a friend of mine mentioned something about near-UV
>light being cheaper to get at than actual UV light. Does anyone
>know what he was referring to?

As far as I know, near UV (as opposed to far-UV) is longwave UV (near
the visible spectrum).  Longwave UV is safer as far as accidental (I hope)
exposure to the eyes.  As far as fluorescent minerals go (the reason a
friend has a UV lamp), some only respond to only one of short or long UV.

Hope this helps.

Dave.



>
>Thanks much.
>
>
>--
>John Hawkinson
>jhawk@panix.com
 ---------------------------------------------------------------------- 
| Who I am:  David Malecki                                             |
| Who you think I am:  dramalecki@electrical.watstar.uwaterloo.ca      |
|                                                                      |
 ----------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 53960
From: karplus@cse.ucsc.edu (Kevin Karplus)
Subject: Re: decoupling caps - onboard


I've used on-chip capacitors to reduce ground-bounce noise on a small
systolic array chip that had 50pF loads on the clock lines.
(Design was in 2-micron n-well cmos, using the MOSIS scalable design rules.)
Here are some thoughts on the bypass capacitors:

1) They don't help much with simultaneous output switching--there is
	still a large inductance between the bypass capacitor and the
	load capacitor (on both the signal line and the ground
	return), so you still get ground and power line bounce. 

2) They do help a lot with on-chip loads, as I had with the high load
	on the clock lines. 

3) The transients you are trying to suppress are really high
	frequency, so forget about large areas of poly-thin-oxide-diff
	capacitors, since the RC time constant is too large.
	What I did is to make a metal2, metal, poly, diff sandwich,
	but put a lot of holes in the poly layer, allowing frequent
	diff-metal1 contacts.  I forget exactly how wide the poly
	lines were.  If I were doing this design again, I'd probably
	omit the diff altogether, and use a solid poly sheet instead,
	using just m2, m1, and poly (and substrate, but that has such a high
	resistance it can be ignored at these speeds).

4) You are probably better off trying to tune your circuit to run with
	slightly slower edges and lower voltage swings (especially for
	output signalling), than spending chip area on capacitors.
	I had spare space on the die since the circuit was too big for
	a MOSIS tiny chip, and the next size up was twice as big as I
	needed. 

Kevin Karplus
-- 
Kevin Karplus		karplus@ce.ucsc.edu

Due to budgetary constraints the light at the end of the tunnel is
being turned off.

Newsgroup: sci.electronics
document_id: 53961
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Anyone got 200+ Schadow switches with LED?

Name your price, cap colours & quantity available.
cheers
Mike

Newsgroup: sci.electronics
document_id: 53963
From: mycal@NetAcsys.com (Mycal)
Subject: Need to find out number to a phone line 


try comp.dcom -  I was reading a thread a while back about an 800 number
that you could dial.  worked here.  It was a sales line for sprint I think
telling you that you could have all your customers numbers using there
ANI, then it told you your number.  Should work with any modern switch.

mycal


---------------------------------------------------------------------------
PGP key on request.       mycal@netacsys.com
                                                              \ //
Mycal's way of skiing moguls:                                 // \
turn, turn, turn, air, survive, survive, survive...     No Risk, No Rush

Newsgroup: sci.electronics
document_id: 53964
From: mycal@NetAcsys.com (Mycal)
Subject: ATARI 2600 Processors 


For all people that are interested in every aspect of the 2600 try the
zine:

2600 connection
$1 cash to :
Timothy Duarte
PO Box N, 664
Westport, MA 02790

for sample



---------------------------------------------------------------------------
PGP key on request.       mycal@netacsys.com
                                                              \ //
Mycal's way of skiing moguls:                                 // \
turn, turn, turn, air, survive, survive, survive...     No Risk, No Rush

Newsgroup: sci.electronics
document_id: 53965
From: rubin@cis.ohio-state.edu (Daniel J Rubin)
Subject: Re: arcade style buttons and joysticks

> Hi there,
> Can anyone tell me where it is possible to purchase controls found
> on most arcade style games.  Many projects I am working on would
> be greatly augmented if I could implement them.  Thanx in advance.

Try Parts Express in Dayton, Ohio also.  They have a complete line of 
professional arcade buttons, joysticks etc...

The have a 1-800 number so call 1-800-555-1212 and ask them what the 1-800
number for Part Express in Dayton, Ohio is.  I love the free 1-800 directory 
assistance...

                                                               - Dan
-- 
             Daniel Joseph Rubin     rubin@cis.ohio-state.edu 
     
                       GO BENGALS!      GO BUCKS!

Newsgroup: sci.electronics
document_id: 53966
From: alan@apple.com (Alan Mimms)
Subject: Re: UART needed (really BREAK detect)

In article <jam.19.735404158@ameslab.gov>, jam@ameslab.gov (Jerry
Musselman) wrote:
> 
> I need to find a UART that will interface to an 8051 and do the following:
> 	-250k baud, 8 data bits, 2 stop bits, no parity
> 	-ability to do BREAK detect (IRQ or output pin)
> 	-IRQ on character received
> 
> I'm using a Dallas DS2250 at 16 Mhz (8051 clone), but it won't do 
> break detect.  I've looked at the 6850, 8251, 7201, 2661, etc...
> 
> 	Any help would be appriciated!!!

Actually detecting a BREAK is done by watching for a "character" containing
all zero bits with the framing error resulting from its receipt.  This
means that the line stayed in the zero bit state even past the stop bit
time slot, which basically indicates a BREAK.  There is no special way to
detect BREAK that I have found other than this -- there's no magic signal
generated by UARTs, etc.

Alan Mimms (alan@apple.com, ...!apple!alan)   | My opinions are generally
Portable Macintosh Software Group             | pretty worthless, but
Apple Computer                                | they *are* my own...
Art without engineering is dreaming.  Engineering without art is
calculating.
	-- Steven K. Roberts in "Computing Across America"

Newsgroup: sci.electronics
document_id: 53967
From: mb4008@cehp11 (Morgan J Bullard)
Subject: Re: Uninterruptible Power Supply

alung@megatest.com (Aaron Lung) writes:

>In article <1qk724INN474@hp-col.col.hp.com> cab@col.hp.com (Chris Best) writes:
>>I'm no expert at UPS's, but you said something that made it sound like
>>you didn't realize something.  On a typical UPS (well, on ours, anyway),
>>there is NO switchover from AC to DC.  All the protected equipment is
>>ALWAYS running from the batteries (via an inverter), with the usual 
>>condition of also having them on charge.  If the power fails, big deal - 
>>the computers never see it (until the batteries start to droop, but 
>>there's something like 60 car-sized batteries in that cabinet, so it 
>>takes a while).
>>
>>If you were gonna run the guts on straight DC instead of an inverter,
>>why not do it all the time?  Then there'd be no switchover to screw
>>things up, and no having to sense the failure fast.  Just keep the DC
>>on charge when the power is on, and it'll be there in zero time when
>>you "need" it.
>>

>Actually, it's a bit more complicated than that...I sounds to me,
>your UPS takes in AC, rectifies it to DC to charge the batteries, and
>then takes the battery DC and chops it to AC again, feeding your
>equipment.  This approach is the easiest and cleanest way to
>switchover from the mains to battery once your power kicks out since,
>as you mentioned, nothing will know about what happened down the line.

>Another way to do the UPS scheme is to use the mains until you
>lose power, and then kick in the battery backup with it's inverter to
>replace the lost power.  The problem here is the switchover time and
>you've got to resync the AC in no time flat.
That's a standby unit not a UPS, otherwise there would be no interuption.
Many standby units are labled as UPS's though.  
 			Morgan Bullard mb4008@coewl.cen.uiuc.edu
				   or  mjbb@uxa.cso.uiuc.edu


>Unfortunately, most everything is built around the assumption that
>AC is available, so the UPS guys have to provide and AC output to
>be usable...ya sorta have to make it work with what there already.

>Similar story with our telephone system.  It was first invented back
>in the 1800's.  We're still using the same damn system (media) as they
>did back then.  If I have a phone from back then, I can assure you
>it'll work on today's phone system.  It costs too much to overhaul
>everyone to a new system, so they make it work with what is out there.

>.

Newsgroup: sci.electronics
document_id: 53968
From: ritterbus001@wcsub.ctstateu.edu
Subject: Re: IR remote control receiver

In article <wb9omc.735429954@dynamo.ecn.purdue.edu>, wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes:
> ab616@Freenet.carleton.ca (Marc Dion) writes:
> 
> 
>>For a project of my own, I would like to build a Infra-Red Remote control
>>receiver (for regular VCRs and TVs remotes).  Does anybody have any info
>>or tips on how to build such receiver ?
>>In particular,
>>a) which photo detector should I use (which wavelength do remotes use) ?
>>b) which ICs or circuit should I use ?
>>c) any suggestions for circuit layout
> 
> 	Another suggestion - find a brand of TV that uses an IR remote,
> and go look at the SAMS photofact for it.  You can often find some very
> detailed schematics and parts list for not only the receiver but the
> transmitter as well, including carrier freq. specs. and tone decoding
> specs. if the system uses that.
> 
Probably won't help.  I'd be willing to bet that _every_ manufacturer
used those little self-contained modules.  I think Sharp made them.
Radio Shack used to sell them for a few bucks (maybe they still do.)

The module had 3 leads:  power, ground and demodulated output.  It
contained the photo-detector, amplifier, integrator and demodulator
all in a tiny metal can.

If you want to buy one, try Radio Shack, or else a TV repair shop can
probably order one.  BTW - the carrier frequency is 40 KHz, and each
different TV/VCR/cable box/stereo manufacturer uses a unique pulse
scheme to perform each different function on their equipment.


Jim Ritterbusch
ritterbus001@wcsu.ctstateu.edu    - or - ne22@radiomail.net  (temp, rf)
There is an art, the Guide says, or rather a knack to flying.  The
knack lies in learning how to throw yourself at the ground and miss.


Newsgroup: sci.electronics
document_id: 53969
From: craw@yoyo.cc.monash.edu.au (Sebastian Filzek)
Subject: IR detector 'cards'???

Hi people..

OK heres my problem.... 
I keep hearing about these little credit card type of things which
detect IR light....

I believe that you have to 'charge them up' under normal (visible) light
and then if they are exposed to IR light they glow or something like
that...

I think that they are avaliable in the states and even in England, but
alas I live in Australia.  Could someone please inform me if I can get
these things over here, and if so where??? and how much???

Also are they really commonly avaliable in the states, and if so, then
how much are they and who sells them (maybe if I cant get one here, I'll
write to one of the companies over seas..)

Anyway.... Thanks in advance...

Sab
93


Newsgroup: sci.electronics
document_id: 53970
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: Re: Suggestions  on Audio relays ???

>In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>I built a little project using the radio shack 5vdc relays to switch
>>audio.  I got pretty bad 'clicks' when the thing switched. 
>
>>	Is there a good relay/relay circuit that I can use for switching
>>audio, so that there will be *NO* noise of any kind on the audio lines.
>
I missed the first part of this thread; are you switching line level or
speaker level audio?
If line level, there's a single chip 4x1 *stereo* audio switch available
that switches 4 two-channel inputs into 1 two-channel output, and also
has a mute function, all controllable with ttl inputs.  LM1037, I think?

If speaker level, never mind.  :(

Phil Torre (ptorre@u.washington.edu)



Newsgroup: sci.electronics
document_id: 53971
From: franko@cco.caltech.edu (Frank Filipanits)
Subject: Re: arcade style buttons and joysticks

> > Can anyone tell me where it is possible to purchase controls found
> > on most arcade style games.  Many projects I am working on would
> > be greatly augmented if I could implement them.  Thanx in advance.

>HAP controls just outside Chicago sells these.
>						Andrew MacRae

Actually, it's HAPP, and some of their equipment can be found in the 
Parts Express catalog (1-800-338-0531).  They show switches for $2,
joysticks for $13 and trackballs for $80.  They also have pinball parts.

Good luck.


-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Frank Filipanits Jr.    B.S. EE/Music, California Institute of Technology '92
Audio Consultant          M.S. Music Engineering, University of Miami     '94
franko@alumni.caltech.edu   "No, officer, I don't know how fast I was going."

Newsgroup: sci.electronics
document_id: 53972
From: mcmahan@netcom.com (Dave Mc Mahan)
Subject: Re: 8x oversampling CD player

 In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>
>>I just bought a new portable CD player for the office, and I notice that
>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>>I understand what oversampling is (the rate of discrete "samples"
>>exceeds the highest frequency component of interest by some factor),
>>I don't understand this "8 TIMES" business...  It seems to me that when
>>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>>senile?  If I'm not, then what good does it do for the player to take
>>samples at a higher rate?  

>The data is only ever read once (barring mistracks and such, of course),
>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>Oversampling takes two discrete data points, and interpolates n-1 points
>between them for n times oversampling.  When I asked, people said that the
>interpolation was not simply linear interpolation, but significantly more
>complicated.

You are quite correct in your understanding.  The filtering is not
interpolation, as that would distort the frequency content of the signal
you are listening to.  Generally, these players run the samples thru an
all-pass filter network.  I have done this for ECG waveforms from a person's
heart, and the effect is rather spooky.  It actually reconstructs peaks
that weren't there (correctly, too!) and fills in the gaps with the
properly computed values, just as if there had been a real sample taken at
that point.  I use a CPU to do all the math.  It takes a decent (but not
unreasonable) amount of CPU time to do this.  You can keep up with things
in realtime if you write efficient code.

In case you care, the filtering method uses an FIR (finite impulse response)
filter.  I'd guess that CD makers use the same kind of method.  Anybody out
there know the real answer?  I'd say that they use a tapped delay line with
resistor/op-amp weighting to accomplish the filtering.  This strikes me as
the most cost effective method for volume production runs.


>Anyway, then, the purpose of oversampling is to move the "effective"
>sampling rate up to n times 44.1 KHz, in order to use higher frequency
>antialiasing filters.  For the same quality filter, higher oversampling
>lets you build cheaper filters, whereas for the same price filter, higher
>oversamplings lets you build better filters.  So, assuming the quality of
>all other components in a CD player remained the same, oversampling should
>allow a manufacturer to produce _slightly_ better sound due to anti-alias
>filtering.

Actually, I think the only reason they do this is so that they can say that
they have a marketting gimic.  I would guess that it is acutally cheaper to
filter an oversampled signal than not.  You can use sloppier components and
give the filter a roll-off that isn't so sharp.   It's too bad that they
charge more for something that (I think) is actually less costly to build.

I seriously doubt that the filters cost the same but are better.  They are
built to a price spec, and that spec says "cheap as possible!". 


>					---Joel Kolstad

  -dave
-- 
Dave McMahan                            mcmahan@netcom.com
                                        37N 17.382    121W 59.190 

Newsgroup: sci.electronics
document_id: 53973
From: rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter)
Subject: Can Radio Freq. Be Used To Measure Distance?

I'm wondering if it's possible to use radio waves to measure the
distance between a transmitter(s) and receiver?

Seems to me that you should be able to measure the signal strength
and determine distance. This would be for short distances (2000 ft),
and I would need to have accuracy of 6 inches, or so.

How about measuring vertical distance as well, any chance - or am I getting
ridiculous?

What frequencies would be best for this? Or does matter?

Sorry if I'm "mucking up" the network with one of those questions best
answered by Bill Willis via US Mail... and I apologize for not being
"tuned-in" to electronics. :-)


R.G. Carpenter, Ph.D., P.E. (sorry... only an ME)


Newsgroup: sci.electronics
document_id: 53974
From: pauls@trsvax.tandy.com
Subject: Re: Need source for old Radio Shack ste


 It's made by Rohm. (as is all BAxxx parts). Call 714-855-2131 and ask if
 you can get a sample (it's only like a $2 part).



Newsgroup: sci.electronics
document_id: 53975
From: pauls@trsvax.tandy.com
Subject: Re: Need Info on DSP project


Motorola has a good app note on a 10 band equalizer using a 56000 DSP. It
could be easily ported to an Ariel board, or even a Turtle Beach 56K
development system.



Newsgroup: sci.electronics
document_id: 53976
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <C5v13M.C37@bcstec.ca.boeing.com> rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>I'm wondering if it's possible to use radio waves to measure the
>distance between a transmitter(s) and receiver?

Yes, you could.

>Seems to me that you should be able to measure the signal strength
>and determine distance. This would be for short distances (2000 ft),
>and I would need to have accuracy of 6 inches, or so.

Well, letsee (whipping out HP-48SX, soon to be GX): 6 inches/3*10^8 m/s=.5
nanoseconds resolution.  Hmm.  That'll be rather difficult!

The more standard (read: better) method is to use ultrasound, generally
somewhere around 40kHz.  Sound travels a heck of a lot slower than light
(radio waves), and is therefore much easier to deal with.

>What frequencies would be best for this? Or does matter?

It might be easiest to visit a hardware store and look at the numerous
"sonic estimator" type devices that do what you want here.  Many are pretty 
cheap too -- <$30.  (In fact, for awhile the Stanley Estimator was selling
for something like $8.  That's the one I bought! :-) )

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 53977
From: system@garlic.sbs.com (Anthony S. Pelliccio)
Subject: Re: Beginner's RF ???

klink@cbnewsl.cb.att.com (steven.r.klinkner) writes:

> Can anybody recommend a good, application-oriented beginner's reference
> to RF circuits?  
> 
> I am pretty good on theory & know what different types of modulation mean, 
> but don't have a lot of practical experience.  A book detailing working
> circuits of different types (modulation, power, frequency, what is legal,
> what is not, et cetera), would be very helpful.
> 
> Thanks.

Well, you might try the A.R.R.L.'s license study guides. For example, my
Advanced Class study guide has lots and lots of good RF and electronics
theory in it. I would imagine the other books are good too.

Tony

-----------------------------------------------------------------------
-- Anthony S. Pelliccio, kd1nr/ae    // Yes, you read it right, the  //
-- system @ garlic.sbs.com          // man who went from No-Code    //
-----------------------------------// (Thhhppptt!) to Extra in     //
-- Flame Retardent Sysadmin       // exactly one year!            //
-------------------------------------------------------------------
-- This is a calm .sig! --
--------------------------


Newsgroup: sci.electronics
document_id: 53978
From: system@garlic.sbs.com (Anthony S. Pelliccio)
Subject: Re: arcade style buttons and joysticks

dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:

> Hi there,
> Can anyone tell me where it is possible to purchase controls found
> on most arcade style games.  Many projects I am working on would
> be greatly augmented if I could implement them.  Thanx in advance.
> 
> -Dave
> dnewman@lynx.dac.northeastern.edu
> 

Contact Chris Arthur at Chris_Arthur@pennies.stratus.com
He restores lots of old video and arcade games and knows where to get
parts.

Tony

-----------------------------------------------------------------------
-- Anthony S. Pelliccio, kd1nr/ae    // Yes, you read it right, the  //
-- system @ garlic.sbs.com          // man who went from No-Code    //
-----------------------------------// (Thhhppptt!) to Extra in     //
-- Flame Retardent Sysadmin       // exactly one year!            //
-------------------------------------------------------------------
-- This is a calm .sig! --
--------------------------


Newsgroup: sci.electronics
document_id: 53979
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <wb9omc.735430855@dynamo.ecn.purdue.edu>, wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes...

>	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
>6 WATTS.  I don't have the book here at work so I can't recall the company
>name.  The 6 watter ain't cheap, around $108 but if you want some power,
>mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
>1 watt device in their line, and will sell small quan. to individuals.
>If you are interested, I can find the book at home and get the
>pertinent info.
> 

You are probably referring to the products of
		
		Opto Diode Corp.
		750 Mitchell Road
		Newbury Park Ca 91320
		805 499-0335

The make some amazing IRLED's.  The really high-powered devices are arrays of
3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
designed as illuminators for IR vision systems.

I would also be interested in the application here.  I work with a Dance and
Technology program, and want to build something to track dancers on a 30 foot
wide stage from 50 feet away.

Newsgroup: sci.electronics
document_id: 53980
From: mcovingt@aisun1.ai.uga.edu (Michael Covington)
Subject: Re: Radar detector DETECTORS?

There is or was a microwave tower next to Florida's Turnpike, and you
could watch the cars hit the breaks as they came in sight of it every
morning...

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 53981
From: schaerer@isi.ethz.ch (Thomas Schaerer)
Subject: Re: Voltage regulation and current limiting

Andy Collins (acollins@uclink.berkeley.edu) wrote:
: One not-so-quick question to throw out there for you guys...

: For our class project, we need to design and build a power supply
: to the following specs:

: Voltatge:  adjustable from 1-12V
: Current:   *limited* at 1A

: Voltage must stay within 2% of designated value for I from 0-1A
: AC ripple less than 5 mV (rms)

To decide which kind of circuit you must know the initialprecission of
the limiter-current and the allowed temp-drift.

In the first case, you can use a Ube of a transistor as a voltage-reference
of about 0.7 VDC with a temp-drift of 2mV/K. In the second case its better
you use a bandgap-ref and a opamp-circuit to detect the maximum-current.
The output of this opamp controlls the outputstage to limit the current.

Bye Thomas

Newsgroup: sci.electronics
document_id: 53982
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Fujitsu 8" HDD

In article <1993Apr17.204351.2256@aber.ac.uk> cjp1@aber.ac.uk (Christopher John Powell) writes:

[deletions]

>It appears to use two balanced-line connections, but what each connection
>corresponds to I know not. One connection is a 30-way IDC, the other a
>60-way IDC.

Sounds like it is an SMD interface to me, not being at work now
to actually count pins.  there are two varients, SMD  and
SMDC (I think), only minor differences between them.  Widely used
prior to the advent of SCSI for large drives (or all drives) on minis
(and mainframes(?) no experience on those).

Richard Dell

Newsgroup: sci.electronics
document_id: 53983
From: gregpen@crash.cts.com (Greg Penetrante)
Subject: Re: Adcom cheap products?

In <1qmbi7$aln@transfer.stratus.com> Michael_LaBella@vos.stratus.com writes:

>I gather by off-shore assembly you mean that adcoms are built by 
>blue-fin tuna's who are into that squid-fi sound?  (I agree on that one). 
>My Adcom 555 preamp did sound better after installing the famous  
>"running the chips class "A" resistor mod", and replacing the metal 
>bottom cover with plexiglass,, too bad the factory could not make em sound 
>better,, but better sound, unfortunately, does not appear to be a priority 
>with Adcom, else the mods would neither have been necessary, nor would they 
>have improved what was already touted as superlative state-o-d-art le'sound. 
>I really want to hear from all those people out there who have traded up  
>from an sp9II (even an sp3a!) to a GFP-555/etc., or maybe from those that 
>have dumped their forte' amps for a GFA-555/etc....  



I am one of those folks who traded UP from a 500 to an Audio Research SP9 II!

:-)

Am I enjoying it? Yes!  The SP9 DOES sound better... but at a price.
-greg


Newsgroup: sci.electronics
document_id: 53984
From: plumpe@oasys.dt.navy.mil (David Plumpe)
Subject: Re: Pink Noise

In sci.electronics, wayne@uva386.schools.virginia.edu (Tony Wayne) writes:
>What is Pink noise and how is it used in sound experiments?

    Pink noise has constant power per geometric frequency increment
(octave, 1/3 octave, etc).  Thus the 10kHz-20kHz octave has the same
amount of noise power as the 10Hz-20Hz octave.
    White noise has constant power per arithmetic frequency increment
(Hz, kHz, etc).  Thus the 10kHz-10.1kHz band has the same amount of
noise power as the 10Hz-110Hz band (both bands are 100Hz wide).
    Pink noise can be made by passing white noise thru a -3db/octave
filter (usually approximated by a network of several RC pairs).
Note: you can't get -3db/octave by using half a -6db/octave network 
:-(
    Pink noise is commonly used in audio power response measurements.
It shows up on audio spectrum analyzers (with octave-related bands)
as a flat line across the bands.

DaveP

Newsgroup: sci.electronics
document_id: 53985
From: hughes@jupiter.ral.rpi.edu (Declan Hughes)
Subject: Manual for Eprom Blower (Logical Devices Prompro-8) Wanted


  I have an eprom blower made by Logical Devices and the
 model name is Prompro-8, but I have lost the manual. Does anyone
 have a spare manual that they would like to sell ?

   Declan Hughes
   hughes@ral.rpi.edu

Newsgroup: sci.electronics
document_id: 53986
From: 880518l@dragon.acadiau.ca (Nelson Langille)
Subject: Re: Need Info on DSP project

There is a file at the simtel archives called adda10.zip I think that
is for DSP.

Newsgroup: sci.electronics
document_id: 53987
From: markz@ssc.com (Mark Zenier)
Subject: Re: MC SBI mixer

Mark J. Musone (musone@acsu.buffalo.edu) wrote:
: HI, I was wondering if anyone would be able to help me on twwo related
: subjects. I am currently learning about AM/FM receivers and recieving
: circuits. 
: 
: P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
: ELECTRICAL DIAGRAMS would help a lot.
: I have seen a lot of theory books with no circuits and a lot of
: circuit books with no theory, but one without the other does not help.

A pretty serious book that still seems readable is

Communication Receivers, Principes and Design
by Rohde and Bucher.


Mark Zenier  markz@ssc.wa.com  markz@ssc.com  

Newsgroup: sci.electronics
document_id: 53988
From: idh@nessie.mcc.ac.uk (Ian Hawkins)
Subject: Making up odd resistor values required by filters

When constructing active filters,  odd values of resistor are often required 
(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
capacitor values and cope with the strange resistances then demanded).

Is there a PD program out there that will work out how best to make up such
a resistance, given fixed resistors of the standard 12 values per decade?.(1,
1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
q and finding prefered values x,y and z.


			Cheers
				Ian H  


Newsgroup: sci.electronics
document_id: 53989
Subject: Re: electronic parts in NYC?
From: david tillyer <DATCC@CUNYVM.BITNET>

Does anyone here know where I can find a modem and comm. software for
an Apple IIe?  I would prefer in Manhattan, but New Jersey would
work too.  David Tillyer, DATCC@CUNYVM.CUNY.EDU

Newsgroup: sci.electronics
document_id: 53990
From: tgg@otter.hpl.hp.com (Tom Gardner)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In sci.electronics, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:

> I'm wondering if it's possible to use radio waves to measure the
> distance between a transmitter(s) and receiver?

Yes. It's called RADAR.

> Seems to me that you should be able to measure the signal strength
> and determine distance. This would be for short distances (2000 ft),
> and I would need to have accuracy of 6 inches, or so.

Depends on the environment: in a static environent such as a waveguide yes, in
a dynamic environment (with objects moving about) the multipath kills this
concept.

> How about measuring vertical distance as well, any chance - or am I getting
> ridiculous?

What is the difference between vertical and horizontal?

> What frequencies would be best for this? Or does matter?

This depends on the required range, the required accuracy, the allowable
ambiguity in range, the frequencies the FCC (etc) allow you to use.

Newsgroup: sci.electronics
document_id: 53991
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: Pink Noise

Tony Wayne writes:

>What is Pink noise and how is it used in sound experiments?
>-tony

Pink noise is a random signal with more low-frequency components
than white noise.

If you look at the frequency spectrum of white noise at a frequency
analyzer, you will find that the spectrum power density is flat, which
means that every frequency is present in the noise signal.

Often pink noise is obtained from white noise by integrating of low-pass
filtering a white noise signal. Therefore pink noise contains much more
low-frequency components.

The effect of pink noise is sometimes used to simulate thunder or roaring
animals. An additional low-pass filter with variable cutoff frequency will
explain you why.

Enjoy it.

Wouter.

Newsgroup: sci.electronics
document_id: 53992
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: 8x oversampling CD player

mcmahan@netcom.com (Dave Mc Mahan) writes:

> In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>>
>>>I just bought a new portable CD player for the office, and I notice that
>>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>>>I understand what oversampling is (the rate of discrete "samples"
>>>exceeds the highest frequency component of interest by some factor),
>>>I don't understand this "8 TIMES" business...  It seems to me that when
>>>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>>>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>>>senile?  If I'm not, then what good does it do for the player to take
>>>samples at a higher rate?  

>>The data is only ever read once (barring mistracks and such, of course),
>>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>>Oversampling takes two discrete data points, and interpolates n-1 points
>>between them for n times oversampling.  When I asked, people said that the
>>interpolation was not simply linear interpolation, but significantly more
>>complicated.

>You are quite correct in your understanding.  The filtering is not
>interpolation, as that would distort the frequency content of the signal

They do interpolate - it's not linear interpolation though. You are correct
that the frequency content is not altered (more specifically, the baseband
spectrum is preserved, and so is every Nth image spectrum. The other
(N-1) in N image spectra are removed, where N is the oversampling rate)

>you are listening to.  Generally, these players run the samples thru an
>all-pass filter network.  I have done this for ECG waveforms from a person's

Ideally the filter has a gain of 1 from 0Hz to 22050Hz, and a gain of 0
from 22050 to the new Nyquist frequency. In practice a finite transition
band is required, and there is also a certain amount of pass-band ripple
and stop-band leakage. With a high order (eg 200 taps) digital filter,
a very good approximation can be easily achieved.

 <<< BIT DELETED ABOUT OBSERVATIONS OF INTERPOLATION FILTER AT WORK >>>

>In case you care, the filtering method uses an FIR (finite impulse response)
>filter.  I'd guess that CD makers use the same kind of method.  Anybody out
>there know the real answer?  I'd say that they use a tapped delay line with
>resistor/op-amp weighting to accomplish the filtering.  This strikes me as
>the most cost effective method for volume production runs.

No, they actually use a digital FIR just like yours, but built in hardware,
on custom VLSI chips for (mainly) economic reasons.

>>Anyway, then, the purpose of oversampling is to move the "effective"
>>sampling rate up to n times 44.1 KHz, in order to use higher frequency
>>antialiasing filters.  For the same quality filter, higher oversampling
>>lets you build cheaper filters, whereas for the same price filter, higher
>>oversamplings lets you build better filters.  So, assuming the quality of
>>all other components in a CD player remained the same, oversampling should
>>allow a manufacturer to produce _slightly_ better sound due to anti-alias
>>filtering.

>Actually, I think the only reason they do this is so that they can say that
>they have a marketting gimic.  I would guess that it is acutally cheaper to
>filter an oversampled signal than not.  You can use sloppier components and
>give the filter a roll-off that isn't so sharp.   It's too bad that they
>charge more for something that (I think) is actually less costly to build.

I guess that the answer is somewhere between the two.

As an interesting (?) aside, some of you out there may be aware of a scheme
used by Pioneer and Wadia, which is called (by Pioneer, at least) Legato
Link. I haven't heard one of these players, but by reading advertising
blurb, and a couple of pseudo-technical articles I deduced that all they
do is build a lousy digital oversampling filter, and let a load of the
first image (ie aliassed) spectrum through. Talking to Bob Stuart (of
Boothroyd Stuart, aka Meridian) confirmed my suspicion. He said that it
sounded awful, but then he would, wouldn't he...

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
document_id: 53993
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <72020037@otter.hpl.hp.com> tgg@otter.hpl.hp.com (Tom Gardner) writes:
>What is the difference between vertical and horizontal?

Gravity?  Doesn't gravity pull down the photons and cause a doppler shift
or something?





(Just kidding!)


Newsgroup: sci.electronics
document_id: 53994
From: u009@csx.cciw.ca (G. Stewart Beal)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <C5v13M.C37@bcstec.ca.boeing.com> rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>I'm wondering if it's possible to use radio waves to measure the
>distance between a transmitter(s) and receiver?
>
>Seems to me that you should be able to measure the signal strength
>and determine distance. This would be for short distances (2000 ft),
>and I would need to have accuracy of 6 inches, or so.
>
This would be susceptible to fading, multi-path etc. We used to use a
system at the shop made by Tellurometer in South Africa. It used a
10 GHz signal between 2 units across the distance to be measured.
The 10 GHz was just the carrier: the real signals were several switched
ones around 7.5 MHz or so, whose relative phases at the receiver would
read out the digits of the distance down to 10 cm if needed. The units
came with psychrometers (sp?) to measure the relative humidity and
instructions for correction of the measurements due to RH and temp.
They were rather heavy and required an operator at each end.
Current technology uses polarized reflectors, dual polaization TX/RX
and psuedo-random coding of a radar pulse. about the same resolution
at X band, much better at 47GHz. (Only one end is heavy :-)  ).
 
Regards, Stu Beal, VE3MWM, U009@CSX.CCIW.CA,
National Water Research Institute, Burlington, Ontario, Canada.
 
"We'd made it through yet another nuclear winter and
 the lawn had just trapped and eaten it's first robin." - Kyle J. Spiller


Newsgroup: sci.electronics
document_id: 53995
From: djbarnes@eos.ncsu.edu (DONALD JAMES BARNES)
Subject: Re: arcade style buttons and joysticks


In article <1r53r8INNq0i@gap.caltech.edu>, franko@cco.caltech.edu (Frank Filipanits) writes:
> > > Can anyone tell me where it is possible to purchase controls found
> > > on most arcade style games.  Many projects I am working on would
> > > be greatly augmented if I could implement them.  Thanx in advance.
> 
> >HAP controls just outside Chicago sells these.
> >						Andrew MacRae
> 
> Actually, it's HAPP, and some of their equipment can be found in the 
> Parts Express catalog (1-800-338-0531).  They show switches for $2,
> joysticks for $13 and trackballs for $80.  They also have pinball parts.


You're right, it is HAPP Controls, Inc., but you can buy direct from them.  I
don't have a phone number with me, but anyone interested in it can email me for
it.  I don't remember their button price, but the joystick price was $8.95
per dozen at last check.  Should be slightly higher for one or two, but cheaper
than Parts Express.  As for the trackballs, i don't know the new price either.
But I can sell you rebuilt arcade trackballs for $50.  That includes new rollers
and new bearings (when nec.).  I also have a pile of used joysticks and buttons
that i would be willing to sell.  Please email to address below if interested.

--Donnie

///////////////////Please note the new email address below////////////////////
******************************************************************************
Donald Barnes	         |         "Coach, I'm having blackouts."
barnes@yoda.csc.ncsu.edu |
Computer Engineering	 |  "Kind of a nice break in the day, isn't it Sam."
N.C. State University    |			
******************************************************************************

Newsgroup: sci.electronics
document_id: 53996
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

That depends entirely upon the advertiser whose number you circled.
Radio Electronics compiles all of the cards, then each advertiser
gets a computer printout of the names and addresses of all of the readers
who circled their number. Some magazines also provide the data on
self-adhesive labels, and the really big magazines provide the
data on computer disk.

The advertiser decides what to do with the data they get. You will
notice that the Radio Electronics information card (commonly called
a "bingo card" in the industry) includes lines for a company name
and a business phone number. My guess would be that the big, national
advertisers make a distinction between hobbiests and professionals as
best they can. For example, if you include Motorola as your company
and include a business phone (and a mail stop), Tektronics will probably
send you a copy of their hard-bound catalog and have a sales engineer
call you about a week later. If you leave it blank, odds are they
will send you a slick brochure and direct you to a local retail
outlet. Medium and small companies are more likely to send you th
e whole catalog. And then some companies, like Digikey or Jameco, have
nothing to mail out accept the catalog.

A couple of other interesting points about bingo cards: Free, industry
magazines like EDN and such also log your card to their computer. They
use the information at least three ways. They note that you really do read
the magazine and are more likely to continue your subscription or push
you, through repeated mailings, to re-subscribe. They also compile
how many people requested which data for their marketing demographics.
This way thay can tell a prospective advertiser that "23% of readers
requesting data were interested in capacitors." And finally, some
magazines rent lists of readers who request certain information. For
example, Tektronics can rent a list of everyone who requested information
about test equipment OTHER THAN TEKTRONIC's, in the past 6 months.

The other point, in the data the advertiser receives, many magazines
include how many items you circled on the card. If they want, the
advertiser can attempt to cull out the "literature collectors" from
the serious potential customers.

"Can you say qualified sales leads? I thought you could."

What's the BEST way for a hobbiest to deal with bingo cards?

  Never circle more than 8 number on the card. If you want more
  than 8 items, use the second card and mail it a couple of
  weeks later.

  If you are really, really serious and you really, really want
  the information, CALL THE ADVERTISER AND ASK! This will also
  cut about 15 days off the the response time. Virtually
  everyone takes a voice on the phone more seriously than data
  on a computer printout.

  To help insure you keep getting a trade magazine that you're
  not really "qualified" for, send in a bingo card at least every
  other month and circle two or three numbers.

  Include a business name and phone number, even if it's your house.
  Advertisers almost never call. 

John Schuch
  publisher of: The Arizona High-Tech Times
                The Arizona Electrical Journal
                The Arizona HVAC News
  (all of which have bingo cards)



Newsgroup: sci.electronics
document_id: 53997
From: bill@occs.cs.oberlin.edu (Bill Mohler)
Subject: Need Hydrophone Info.


I don't know much about Hydrophones, so I'm looking for any information
that will help avoid problems I haven't thought of! I would like an 
inexpensive hydrophone and amplifier with tape (line level) outputs...
something like Edmund sells for $250. They also sell just the microphone
(hydrophone) head for $24, but how does one construct the enclosure?
Any information would be greatly appreciated, Thanks!

Bill Mohler
bill@occs.cs.oberlin.edu

Newsgroup: sci.electronics
document_id: 53998
From: mjcargil@dux.dundee.ac.uk (M.J.Cargill Psychology ext 4621)
Subject: VIdeo recording of a vga screen

Hi all,

I think the subject says it all - does anyone know how to take the rgb/h/vsync from a standard vga connector and record them on video tape??

Any help is appreciated!


Mark J Cargill

WHY??  I have a program for the PC that I want to videotape so that I can show
people how the program works at a presentation I am giving.


Newsgroup: sci.electronics
document_id: 53999
From: wayne@r-node.hub.org (Wayne Dawe)
Subject: Flexible solar cells

Two or three years ago I saw a report on TV about a company that had 
developed a method of making solar cells on a flexible substrate. My
failing memory has convinced me it was some flexible metal. I now have
an application that requires a flexible solar cell and was hoping someone
out in netland knows something about this company or a similar product.
Any help would be greatly appreciated.
-- 
Wayne Dawe                    (pick a path, any path but don't send me
wayne@r-node.hub.org           anything bigger than 15K)
wayne@r-node.gts.org   wayne@r-node.pci.on.ca     wayne@r-node.UUCP

Newsgroup: sci.electronics
document_id: 54000
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: electronic parts in NYC?

In article <1993Apr21.162414.18000@trintex.uucp> elr@trintex.uucp
	(Ed Ravin) writes:
>Trans-Am Electronics, Canal Street near 7th Ave -- lots of surplus type
>stuff.

They've been out of busines for years.

>Several other electronics or "surplus" type places are still on Canal
>Street.

Not any more.  About 2 years ago they all closed.
When Ramco/Electronics city closed, it took weeks and many
dumpsters to clear everything out (so I heard).
There are a few places that sell connectors and phone wires,
but no chips, capacitors or discrete stuff.

Sylvan/Wellington is still on Broadway and Canal, but they're
not cheap, and not surplus.  It's mostly a TV repairman's store.

-- Jeffrey Jonas
jeffj@panix.com
-- 
Jeffrey Jonas

jeffj@panix.com

Newsgroup: sci.electronics
document_id: 54001
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Long distance IR detection

In article <wb9omc.735430855@dynamo.ecn.purdue.edu> wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes:
>Duane
>	Yeesh, you WILL be nailing those IRLEDs.  May I suggest getting your
>mitts on the Siemens SFH484-2 IRLED?  This unit is designed to take some big
>current pulses if you can get your duty cycle down a bit.  It will output
>nearly a watt (975 mW) with REAL short duty cycle times.
>
>(nice thing about the SFH484-2 is that it is CHEAP.  I got mine for about
>50 cents a piece, even though I had to buy 100 of them....)

Are you saying that you have some extras that you would like to do some cost
recovery on?  I may be interested.  I think for practical and cost reasons I
am limited to envelope detection so that leaves me with only increasing the
output power and increasing the optical gain at the receiver as methods to
extend range.

>	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
>6 WATTS.  I don't have the book here at work so I can't recall the company
>name.  The 6 watter ain't cheap, around $108 but if you want some power,
>mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
>1 watt device in their line, and will sell small quan. to individuals.
>If you are interested, I can find the book at home and get the
>pertinent info.

Yes I'm interested in the company name.  I have access to an extensive data
book collection.  With that kind of power, are we getting into an area where
eye safety is getting to be a problem.

>	Now, as for the position detector, you might try ELTEC in Florida.
>Phone number listed in the 92/93 ETID is 904-253-5328.  They seem like
>nice people.  Their specialty is passive infrared detection devices,
>so they might be able to help you out.

They are a long way from me but they might be a better source than I can find
around here.

>	I'm curious about your applications if you don't mind saying.
>The device sounds like it could be useful in a lasertag game, although you'd
>need to up your carrier signal concept to 58.8 KHz......

I'm keeping my application confidential for now.  Raising the frequency should
be no problem, in fact one respondent to my question said that I may not have
to mimic the 50% duty cycle normally used by IR detector chips.

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
document_id: 54002
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Long distance IR detection

In article <1993Apr22.060607.12380@macc.wisc.edu> jvannes@vms.macc.wisc.edu writes:
> You are probably referring to the products of
>
> 		Opto Diode Corp.
> 		750 Mitchell Road
> 		Newbury Park Ca 91320
> 		805 499-0335
>
> The make some amazing IRLED's.  The really high-powered devices are arrays of
> 3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
> response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
> designed as illuminators for IR vision systems.

Jeez, that should do it.

> I would also be interested in the application here.  I work with a Dance and
> Technology program, and want to build something to track dancers on a 30 foot
> wide stage from 50 feet away.

Very interesting application, controlled lighting and environment, moderate
distances ... might be more interesting than my application.  Just a thought,
you could use a roof mounted IR sender, similar in operation to a TV remote
control that tells each persons coded IR pulser to send a pulse.  A Hamamatsu
detector, as was mentioned in a previous message in this thread, would give
the current position.  Store and collate this on a computer and you could
replay the movements on the screen.  Interesting!

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
document_id: 54003
From: plumpe@oasys.dt.navy.mil (David Plumpe)
Subject: Re: Making up odd resistor values required by filters

In sci.electronics, idh@nessie.mcc.ac.uk (Ian Hawkins) writes:
>When constructing active filters,  odd values of resistor are often required
>(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common
>capacitor values and cope with the strange resistances then demanded).
>
>Is there a PD program out there that will work out how best to make up such
>a resistance, given fixed resistors of the standard 12 values per decade?.(1,
>1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant
>recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with
>q and finding prefered values x,y and z.

    Since you're worrying about the third decimal place, I assume you're
using 1% tolerance resistors and capacitors?


Newsgroup: sci.electronics
document_id: 54004
From: jackp@NETSYS.COM (Jack Powers)
Subject: NTSC horiz & vert drive from black burst?

I would like to hook up some cameras that were recently donated to our
local community cable TV station which have sync inputs in the form
of horizontal and vertical drive. Our station sync is a black burst
which works fine with other boxes with "genlock" style inputs. Can
anyone point me at a design, article, or whatever showing how to produce
the horizontal & vertical drive signals? Thanks in advance.
Jack Powers


Newsgroup: sci.electronics
document_id: 54005
From: schuster@panix.com (Michael Schuster)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

It varies. You may get a catalog or price list from the advertiser, or
if the ad was a specific product - a slec sheet on that product or line.


-- 
Mike Schuster       |        schuster@panix.com | 70346.1745@CompuServe.COM
------------------- | schuster@shell.portal.com | GEnie: MSCHUSTER

Newsgroup: sci.electronics
document_id: 54006
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.141137.863@imag.fr> schaefer@imag.imag.fr (Arno Schaefer) writes:
>In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
>|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
>>>	I guess what I am saying is that your question is difficult, if not
>>>impossible, to answer. What exactly do you want to know?  Do you need a good
>>>one for a project you are working on? How secure must it be?  Are you trying
>>>to crack one that someone else has used?  I can probably make suggestions,
>>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>>legally, to tamper with copy protection.  It can also lead to corruption of
>>>files which you necessarily do not have back ups of (being as they are copy
>>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>>practical applications, and are merely curious?
>>>	Please clear up those questions, and I'll try to help as much as I
>>>can.
>> 
>> May we interpret this as an offer to volunteer as editor for a
>> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>> an initiative! *I* will volunteer to ask some of the questions, if you will
>> provide the answers :-)
>> 
>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>pose: to keep the honest buyer from making (legal) backup copies. It will
>definitely not stop any pirates. If you want to protect you soft, supply a
>good documentation and support. This is IMHO the *only* way of effectively 
>protecting software.

There are several types of copy protection, and the point is to make sure the
user is using a legitimate copy.  The simplest and virtually fool-proof way is
for the program to somehow fixate itself to the machine it was installed on
(some sort of checksum, serial number, whatever) so a copy put on a different
machine (NOT installed from original disks) will not work.  

The program is definitely backupable, if restored to the same machine (depends
on the programmer...  don't use a disk drive characteristic!)  If the user 
did an upgrade to the machine, he/she should reinstall all programs any way.
No document look-up, no disk wear-and-tear!

I did not say that the originals would allow only one install.  The user's 
conscience should do that.

I know, I'll get flamed for this...  But with the increasing number of "casual"
users who either unknowingly or don't care about the software copyrights
(It's the truth.  I have "friends" who ask me for copies of my latest games
all the time, and when I refused, they went after somebody else.), casual
pirating is becoming more of a problem.  Some sort of copy protection will
discourage the casual copying.  I've seen what some of my "friends" dug up
somewhere...  Latest and the greatest games, all cracked, WITHIN days of actual
release!  You know how many bytes you need to change in X-wing to disable
the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)  Determined
pirates are unstoppable, given enough time, but their results do not spread 
that far, since pirate boards are not that well-known, and easily tracked once
found by authorities.  It is the "casual" pirates that the copy protection is
determined to discourage.

What I believe the companies should do is implement the above plus
a special patch once the user registers that loudly exclaims upon bootup
"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
Two benefits: 1) encourages registration, 2) cuts down on pirating and
makes it more traceable, because if the patch's registration message is
encrypted, it will be quite hard to change, and therefore provides a
stable trail of who allowed their copy out of their hands, and thus
violated their license agreement.

This way, the legitimate users who does not register will experience minimal 
discomfort (who does major upgrades to their computer frequently?) as only
problem they have is they won't be able to restore to another computer.

The registered users would have proven they are legitmate users and therefore
gains full rights, and can restore to different machines.  On the other hand,
the software company now have a record of where THIS particular copy is 
supposed to be.  If this user's copy was found to be somewhere it was not 
supposed to be, we know who has broken their license agreement.  Of course,
a hacker can break that eventually, but that's not the point, is it?

--Kasey Chang

Newsgroup: sci.electronics
document_id: 54007
From: mchen@terra.cs.psu.edu (Michael Chen)
Subject: Re: How to the disks copy protected.

If companies compressed their executables with LZW andd did some kind of
encryption in the process, this "change two bytes here" thing would go right
out the window.
--
 Michael Chen			| From the depths of our most lucid horrors |
				| spring our fond hopes and pure desires... |
 mchen@cs.psu.edu		| except what comes from HELL! :-) 7/23/92  |

Newsgroup: sci.electronics
document_id: 54008
From: rgvander@apgea.army.mil (Richard G. Vanderbeek <rgvander>)
Subject: MAGIC layout editor

I heard that MAGIC has been transported to the Macintosh environment.  Does
anybody know where I can get a hold of this?  Thanks in advance for any
responses.

Rich Vanderbeek
Dept of the Army
Aberdeen Proving Ground, MD   

Newsgroup: sci.electronics
document_id: 54009
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: IR detector 'cards'???

In article <1993Apr22.030133.23553@monu6.cc.monash.edu.au> craw@yoyo.cc.monash.edu.au (Sebastian Filzek) writes:
>Hi people..
>
>OK heres my problem.... 
>I keep hearing about these little credit card type of things which
>detect IR light....
>
>I think that they are avaliable in the states and even in England, but
>alas I live in Australia.  Could someone please inform me if I can get
>these things over here, and if so where??? and how much???
>

Sure,

Edmund Scientific Company
101 E. Glouchester Pike
Barrington, NJ, 08007-1380
(609) 573-6250

The card is on page 15 of the last catalog I got. The cost ranges
from $19.00US to $80.00US, depending on size and range of wavelengths
the card responds to.

John



Newsgroup: sci.electronics
document_id: 54010
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

sehari@iastate.edu (Babak Sehari) writes:

>In <1993Apr20.230749.12821@reed.edu> mblock@reed.edu (Matt Block) writes:

>>In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>>>---
>>>
>>>I was wondering, what copy protection techniques are avaliable, and how
>>>effective are they?  Has anyone have any experience in this area?
>>>
>>>                      With highest regards,
>>>                           Babak   Sehari.

>>	Uh oh...
>>	Umm, there are a number of copy protection schemes.  Some involve
>>modifying the physical media, and some involve encryption schemes, &c.
>>	All of the ones that have existed over the course of computing have
>>been successful for a time.  I recall, however, near monthly releases of new
>>ways to "crack" the copy protection scheme of the latest releases.  The fact
>>is, none of them are completely secure, or anywhere near it.  Some are more or
>>less difficult to crack, and some have already been cracked.
>>	I guess what I am saying is that your question is difficult, if not
>>impossible, to answer.  What exactly do you want to know?  Do you need a good
>>one for a project you are working on?  How secure must it be?  Are you trying
>>to crack one that someone else has used?  I can probably make suggestions,
>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>legally, to tamper with copy protection.  It can also lead to corruption of
>>files which you necessarily do not have back ups of (being as they are copy
>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>practical applications, and are merely curious?
>>	Please clear up those questions, and I'll try to help as much as I
>>can.

>>	Incidentally, the "Uh oh..." at the top is indicative of the dread
>>anyone who has watched their friends hacking equipment be carted off feels
>>when they are asked how to hack.  The area you are broaching is wrought with
>>dangers, many of which include breaking the law, or at least addressing it
>>(from one side or the other.)

>>Matt

>I have written a program and I want to market it.  I would like certain degree
>of protection, since my main custmers are individuals and not the 
>cooperations.   I know laser hole burning method, and hardware key method,
>however, my  software is going to cost only $15.00, so I can not afford that.
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.

>However, I do not want someone to get a copy of PCTools and copy my software.  
>Off course, I never meant to forbid the true hackers from copying, since they
>can develope a better program anyway.

>                      With highest regards,
>                           Babak   Sehari.


>-- 

One of the most popular methods of course is the password check where they ask
you for a word from page x, line y, and word z, but this is pitifully simple to
remove unless you throw some checksums into the main part of your program, and
some self-rewriting code to confuse some people.  Also, make sure that your
program can not be run out a debugger.

Another method of course is to not even make bad sectors on the original disk,
just write a certain key to a certain unallocated sector.   To help you here,
you also must do the code protection schemes mentioned in the first paragraph.
Make sure you also fill the rest of the unallocated parts of the disk with
garbage as well, or they (wanna be crackers) can just look for the junk in
some random sector.

Like you mentioned, there are the laser holed disks and hardware keys, but they
are both expensive and a pain in the butt for the end-user, which you is the
opposite of what you want.

Another configuration that can be used is to save the configuration of the
machine that it is being installed to in the most undecipherable format you can
think of.  If the program does not find that this is the same system, it
requests being installed by the original disk again.  The original disk should
be encrypted, compacted, have many sectors that should be checked, and anything
else you can think of to make sure that the original cannot be copied.  Once
again, you MUST put code-encryption, self-rewriting code, and multiple CRC
checks in the program to make sure that it does not get changed.  Among other
things, this also protects your program from virii.  If the program detects a
change in its code, tell the user that a virus has been detected in the
program.  Tell them the program is "VIRUS SECURE", and remember, you have
helped the world kill some pirating and kill some viruses.  Feel good.

I hope that I have helped.  Have fun.  Knock some cracking out (well, you can't
do it, everything that can be written can be cracked, but you'll piss'em off in
the process!). Goodbye.

What is the program that will be sold?
--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54011
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: subliminal message flashing on TV

In article <293@kc2wz.bubble.org> bob@kc2wz.bubble.org (Bob Billson) writes:
>kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan) says:
>>Hi.  I was doing research on subliminal suggestion for a psychology
>>paper, and I read that one researcher flashed hidden messages on the
>>TV screen at 1/200ths of a second.  Is that possible?  I thought the
>
>Take a look over in alt.folklore.urban.  There is a thread about subliminal
>messages on TV.  The fact that subliminal messages don't work aside, an image
>can't be flashed on a TV screen fast enough to not be noticed.

Well, yes and no.  The _image_ can't be on the screen less than 1/30
of a second, but a _mixture_ of images that's about 90% of the field
that was supposed to be there and 10% of the 'subliminal' addition
could be overlaid for one field, producing the same overall effect to
our sluggish retinae of a discrete image projected for 1/300 second.

..although, like the previous poster, I have to reserve my doubts
about the effectiveness of said discrete image in steering my
subconscious around ..

-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
document_id: 54012
From: johne@vcd.hp.com (John Eaton)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

Robert G. Carpenter (rgc3679@bcstec.ca.boeing.com) wrote:
: I'm wondering if it's possible to use radio waves to measure the
: distance between a transmitter(s) and receiver?
: 
: Seems to me that you should be able to measure the signal strength
: and determine distance. This would be for short distances (2000 ft),
: and I would need to have accuracy of 6 inches, or so.
: --------------------
You might try looking at whats available in laser locating systems. They
work best for close work( 1 mile and under).

RF is used for much longer distances in two major modes. Transponder and
phase measurment. Transponder requires you send a pulse to another station
and it returns it to you and you measure the round trip time minus the
receiver time.

Phase measurements require two or more transmitting stations sending the
same frequency signal multiplexed in time. A receiver can pick them up and
measure the phase shift between signals. Maps can be drawn that plot the
Lines of Position that correspond to a certain phase shift between two
stations. 

John Eaton
!hp-vcd!johne



Newsgroup: sci.electronics
document_id: 54013
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

ketil@edb.tih.no (Ketil Albertsen,TIH) writes:

>In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:

>>	I guess what I am saying is that your question is difficult, if not
>>impossible, to answer.  What exactly do you want to know?  Do you need a good
>>one for a project you are working on?  How secure must it be?  Are you trying
>>to crack one that someone else has used?  I can probably make suggestions,
>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>legally, to tamper with copy protection.  It can also lead to corruption of
>>files which you necessarily do not have back ups of (being as they are copy
>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>practical applications, and are merely curious?
>>	Please clear up those questions, and I'll try to help as much as I
>>can.

>May we interpret this as an offer to volunteer as editor for a
>"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>an initiative! *I* will volunteer to ask some of the questions, if you will
>provide the answers :-)

>Ketil Albertsen

That's great.  Read my article.  Edit out the personal formality, and save.
--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54014
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

schaefer@imag.imag.fr (Arno Schaefer) writes:

>In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
>|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
>|> 
>|> >	I guess what I am saying is that your question is difficult, if not
>|> >impossible, to answer.  What exactly do you want to know?  Do you need a good
>|> >one for a project you are working on?  How secure must it be?  Are you trying
>|> >to crack one that someone else has used?  I can probably make suggestions,
>|> >assuming the activity is strictly legal.  (In general, it is a BAD idea,
>|> >legally, to tamper with copy protection.  It can also lead to corruption of
>|> >files which you necessarily do not have back ups of (being as they are copy
>|> >protected,) which can be devestating.)  Do you have absolutely no ideas for
>|> >practical applications, and are merely curious?
>|> >	Please clear up those questions, and I'll try to help as much as I
>|> >can.
>|> 
>|> May we interpret this as an offer to volunteer as editor for a
>|> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>|> an initiative! *I* will volunteer to ask some of the questions, if you will
>|> provide the answers :-)
>|> 
>|> Ketil Albertsen

>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>pose: to keep the honest buyer from making (legal) backup copies. It will
>definitely not stop any pirates. If you want to protect you soft, supply a
>good documentation and support. This is IMHO the *only* way of effectively pro-
>tecting software.

>Best Regards,

>Arno

>-- 
>--------------------------------------------------------------------------------
>Arno Schaefer				ENSIMAG, 2e Annee
>Email: schaefer@silene.imag.fr
>Tel.: (33) 76 51 79 95			:-)
>------- No, you're not paranoid - the world is really out to get you -----------

Your wrong.  Never give up.  Update your program as much as possible, with a
very low price of upgrade to registered users (and *PLEASE* make sure you keep
a list of registered numbers!)...

--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54015
From: swwynen@undergrad.math.uwaterloo.ca (Steve W. Wynen)
Subject: 68008 cross compilers and assemblers (Shareware?)

Can anyone point me to a cross compiler and/or assembler for the Motorola
68008, hosted by a PC compatible.  Preferable Free or Shareware.  

Also does anyone know of a GNU CC port to this chip.

Thanks in advance.


Newsgroup: sci.electronics
document_id: 54016
From: ngupta@geds01.jsc.nasa.gov (ngupta)
Subject: WANTED A SCOPE

I am looking for a 20/40 MHz scope, in good condition.  Please email me or call me at (713)280-2788.


Newsgroup: sci.electronics
document_id: 54017
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR detector 'cards'???

craw@yoyo.cc.monash.edu.au (Sebastian Filzek) writes:


>I think that they are avaliable in the states and even in England, but
>alas I live in Australia.  Could someone please inform me if I can get
>these things over here, and if so where??? and how much???

>Also are they really commonly avaliable in the states, and if so, then
>how much are they and who sells them (maybe if I cant get one here, I'll
>write to one of the companies over seas..)

>Anyway.... Thanks in advance...

>Sab
>93


	I got mine for about 7 bucks at Radio Shack.  The instructions
DO say to expose it to light for a while, but mine doesn't seem to require 
very much to make it work.

	I just wish I could get a big sheet of the stuff, abouit 12" x 12"
for a reasonable price.....it isn't cheap, from what I've seen.

Duane


Newsgroup: sci.electronics
document_id: 54018
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: Long distance IR detection

jvannes@vms.macc.wisc.edu writes:


>You are probably referring to the products of
>		
>		Opto Diode Corp.
>		750 Mitchell Road
>		Newbury Park Ca 91320
>		805 499-0335

>The make some amazing IRLED's.  The really high-powered devices are arrays of
>3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
>response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
>designed as illuminators for IR vision systems.

	Yeah! that's the guys!

>I would also be interested in the application here.  I work with a Dance and
>Technology program, and want to build something to track dancers on a 30 foot
>wide stage from 50 feet away.

	Yeah, that sounds a lot like lasertag anyway....  :-)

Duane


Newsgroup: sci.electronics
document_id: 54019
From: dana@lando.la.locus.com (Dana H. Myers)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)

Oh, yeah.  This is a fine place.  We haven't had the "why does concrete
kill lead-acid batteries" thread in at least six months.

>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  

The concrete simply sucks all the electrons out of the battery and drains
them into the ground.

Another explanation, implausible as it is,  is that the lead-acid battery
needs to be periodically charged (topped-off), otherwise the battery
self-discharges and then undergoes irreversible chemical reaction.

Naawwwww.... the concrete sucks the life out.

-- 
 * Dana H. Myers KK6JQ 		| Views expressed here are	*
 * (310) 337-5136 		| mine and do not necessarily	*
 * dana@locus.com  DoD #466 	| reflect those of my employer	*
 * This Extra supports the abolition of the 13 and 20 WPM tests *

Newsgroup: sci.electronics
document_id: 54020
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR remote control receiver

ritterbus001@wcsub.ctstateu.edu writes:

>If you want to buy one, try Radio Shack, or else a TV repair shop can
>probably order one.  BTW - the carrier frequency is 40 KHz, and each
>different TV/VCR/cable box/stereo manufacturer uses a unique pulse
>scheme to perform each different function on their equipment.

	Some TV's, including my RCA set at home, uses simple carriers
which I think run between 32 and 36 or 38 KHz.  There is no tone decoding
in it.  All one has to do to piss the thing off :-) is just hook an
IRLED up to a variable oscillator and tune through.  Wreaks all kinds
of havoc.  :-)

	Similarly, my VCR remote changes channels on my cable box.  Always
seems to change the cable box to channel 5 when you do the pause/play.

	SOOOO, some things do have some overlap to them.

Duane


Newsgroup: sci.electronics
document_id: 54021
From: anon0188@nyx.cs.du.edu (Einstein)
Subject: I need to access reports on Hall effect Devices.


Does anyone know of the whereabouts of technical reports that
I can access via the Internet?

--
  ______         ___                               
  (/__     . __   (/__) _   . __   /   _   /) _/__  
  (____/\_(_(_____/\_  /-\_(__) )_/_)_(_)_(___/_  
                 (	                         

Newsgroup: sci.electronics
document_id: 54022
From: wally@Auspex.COM (Wally Bass)
Subject: Re: How to the disks copy protected.

In article <sehari.735357542@du139-213.cc.iastate.edu> sehari@iastate.edu
    (Babak Sehari) writes:
  [stuff deleted]
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.

You should be clear in your mind what your goal is. Two possible goals
are (1) maximizing you income from your program, and (2) minimizing
the number of illegal copies which get created. Accomplishing (2)
doesn't usually accomplish (1).

Most vendors have concluded that copy protection reduces the number of
normal legitimate sales by far more than it increase sales by virtue
of changing 'copiers' to 'purchasers', and hence merely reduces
revenue.  Most legitimate buyers nowadays (including me) have had bad
experiences with copy protected products (e.g., hard to make a
legitimate backup, incompatabilties when new system on system upgrade,
etc.), and they won't touch them with a ten foot pole.

Wally Bass



Newsgroup: sci.electronics
document_id: 54023
From: cab@col.hp.com (Chris Best)
Subject: Re: IR detector 'cards'???

> Also are they really commonly avaliable in the states, and if so, then
> how much are they and who sells them (maybe if I cant get one here, I'll
> write to one of the companies over seas..)

----------

Radio Shack, part 276-099, Infrared Sensor Card, $US 5.95

Newsgroup: sci.electronics
document_id: 54024
From: jackb@mdd.comm.mot.com (Jack Brindle)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <72020037@otter.hpl.hp.com> tgg@otter.hpl.hp.com (Tom Gardner) writes:
>In sci.electronics, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>
>> I'm wondering if it's possible to use radio waves to measure the
>> distance between a transmitter(s) and receiver?
>
>Yes. It's called RADAR.
Well, actually not quite. Both Radar and Radio-Altimeters measure distances
by measuring the time required to transmit a signal, then receive its
reflection from a target. Radar generally uses pulses, while Radio Altimeters
use either pulses or a modulated continuous-wave transmission. In the case of
the latter, highly accurate distance measurement can be made. As an example,
the original Bendix ALA-52 Radio Altimeter was accurate to 1/8 foot at 2500
feet altitude.

Note, however that this is a different method of measuring than the poster
originally asked about. The problem with gaining accurate measurements between
a transmitter and a seperate receiver is that you need a highly accurate
time base which starts at the receiver at the exact instant the transmitter
triggers. This cannot be wire connected, since radio waves will actually
travel faster in free-space (air, in this case) than wire (the difference
is called the velocity factor of the cable). So you need to resort to a
common timebase that is automatically corrected for distance, etc. Something
like a PLL connected to a GPS receiver should do the trick, triggering both
the transmitter and receiver simultaneously. Sound expensive? Not too bad,
but plan on spending a few bucks in both equipment and effort.

Why not go to a different method? Surveyors use a laser-light system where again
the reflection time is measured. Why not try this? (Sounds like something a P.E.
should know about anyway ;-).

>> Seems to me that you should be able to measure the signal strength
>> and determine distance. This would be for short distances (2000 ft),
>> and I would need to have accuracy of 6 inches, or so.

This is actually highly inaccurate, since the power output of a transmitter
varies from unit to unit, there are variances in the antenna and transmission
line, and the receiver may also vary, both from unit to unit, and the same unit
over time. You would need to continuously calibrate the entire system. With
the radio altimeter this is also done, but since everything is located at
one place, it is much easier to do. Note especially that the time base for
the R.A. receiver and transmitter is one unit also...

>Depends on the environment: in a static environent such as a waveguide yes, in
>a dynamic environment (with objects moving about) the multipath kills this
>concept.

Nope. FM capture effect says that the strongest signal wins. That is, unless
the two interfering signals are seperated by more than 3 db in signal strength.
This is the one problem that makes altimeters inaccurate at very low altitudes.
Signals bouncing off runways tend to be VERY strong...

>> What frequencies would be best for this? Or does matter?

As high as possible to eliminate outside influence, and also to enhance
attenuation of multipath signals. Radio Altimeters typically use frequencies
around 4 GHz.

Hope this helps...

-- 
==========================================================
Jack Brindle
ham radio: wa4fib
internet: jackb@mdd.comm.mot.com

Newsgroup: sci.electronics
document_id: 54025
From: goofy@howlin.cs.unlv.edu (David Haag)
Subject: Test

This is just a test to see if this works.


Newsgroup: sci.electronics
document_id: 54026
From: kthompso@donald.WichitaKS.NCR.COM (Ken Thompson)
Subject: Re: Cable TVI interference

victor@inqmind.bison.mb.ca (Victor Laking) writes:

)Do you know what frequencies chanels 17 to 19 use and what is usually 
)allocated to those frequencies for broadcast outside of cable?

17 is air comm.
18 is amateur
19 is business and public service

-- 
Ken Thompson    N0ITL  
NCR Corp.  Peripheral Products Division   Disk Array Development
3718 N. Rock Road  Wichita KS 67226   (316)636-8783
Ken.Thompson@wichitaks.ncr.com 

Newsgroup: sci.electronics
document_id: 54027
From: koberg@spot.Colorado.EDU (Allen Koberg)
Subject: Packet Radio on the PC

I'm looking for any and all information regarding packet radio
implementation on the PC.  Software, hardware, whatever.

Please e-mail any info to koberg@spot.colorado.edu.

Thanks

Newsgroup: sci.electronics
document_id: 54028
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Hi Volt from battery

You might want to get a disposible flash camera, shoot the roll of film,
then take it apart (they're snapped together). We used a bunch of them
at my wedding, but instead of sending the whole camera in, I just took
the film out (it's a standard 35mm canister), and kept the batteries
(they use one AA battery). Sorry, I didn't keep any of the flash electronics.

          Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
document_id: 54029
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: 600RPM Floopy drives - UPDATE!

In article <1r3j2lINNf13@clover.csv.warwick.ac.uk> csulo@csv.warwick.ac.uk  
(Mr M J Brown) writes:
> 
> Hopefully this should sort it all out .... not bad for 9 quid (normally
                                                         ^^^^^^

Pardon my ignorance of foreign currency and exchange rates, but what is a  
quid, how does it relate to the British Pound (or whatever it's called)  
and what is that in American Dollars??? :-)

Thanks!

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
document_id: 54030
Subject: help with phone wire: which ones are "tip" & "ring"?
From: mlevin@husc8.harvard.edu (Michael Levin)


I just bought a little gizmo that is supposed to be installed "in
series with the tip or ring lines" of the phone wire. Which ones are
those? Suppose I am holding a regular phone wire, such that the little
plastic tooth (on the little plastic square thing with the naked lead
ends that you plug into the phone) is facing down, and away from me.
Which of the 4 wires that I see is the "tip" and which is the "ring"?
Please reply to mlevin@husc8.harvard.edu.

Mike Levin


Newsgroup: sci.electronics
document_id: 54031
From: cyborg@kauri.vuw.ac.nz (-xivo-Alex Ivopol)
Subject: Re: How to the disks copy protected.

In article <MCHEN.93Apr22131702@terra.cs.psu.edu> mchen@terra.cs.psu.edu (Michael Chen) writes:
>If companies compressed their executables with LZW andd did some kind of
>encryption in the process, this "change two bytes here" thing would go right
>out the window.

Not entirely true. A friend of mine was having trouble finishing the game
GODS and asked me for help since he could not find a "trainer" (small
patch that lets you play without losing lifes). The game is compressed but
I did find *one* byte which when changed in the original *compressed* file
would not affect the decompression and would also prevent the "shield" in the
game from being tured off turning therefore making you invincible.

There are many other progs whose copy protection was defeated one way or
another and I have seen examples of this with my own eyes. The copy
protection schemes defeated were various such as using protected mode,
compressed executables, progs that load and execute other progs (possibly
compressed), dongles, key disks, etc...

I believe that persistence overcomes even the very best copy protection
schemes.

>--
> Michael Chen			| From the depths of our most lucid horrors |
>				| spring our fond hopes and pure desires... |
> mchen@cs.psu.edu		| except what comes from HELL! :-) 7/23/92  |


-- 
Alex T. Ivopol                           cyborg@kauri.vuw.ac.nz
External User - Victoria University of Wellington - New Zealand
************* I speak for myself and no one else. *************

Newsgroup: sci.electronics
document_id: 54032
From: dougwong@cco.caltech.edu (Douglas M. Wong)
Subject: Silicon Storage Inc.

I would appreciate very much the address and/or phone # of 
this company. They supposely make analog EEPROMS. Thanks in
advance.

Doug.

Newsgroup: sci.electronics
document_id: 54033
From: srgxnbs@grace.cri.nz
Subject: Re: CAD Program for Electronics?

>>What I want the CAD program to do is to draw diagrams by
>>dragging elements onto the screen, and in this the elements
>>needed are as diverse as vacuum tubes to ICs (case with pins).
..
try DraftChoice, its not windows but its shareware and object
oriented. Use it with PrintGL for high quality output.

Bruce



Newsgroup: sci.electronics
document_id: 54034
From: gt4417a@prism.gatech.EDU (SKELTON,JOEL PHILLIP)
Subject: help me, i'm not clever! (how to make power supply?)

I need to make a power supply that can take input from a 
cigarette lighter in a car (12v dc) and drive 7.5 volts
at up to 3.0 amps. I know enough to know that a simple
voltage divider with two resistors won't do it right. Can
such a thing be made from Radio-Shack-able parts without
too much difficulty?

jps
bf

p.s. I've looked for premade things like this at radio shack but
none of it seems to go any higher than about 800mA.


-- 
Joel Skelton   --    North Avenue Trade School, Dept. of Round Things
gt4417a@prism.gatech.edu   (ask for Scooter Technologies, and receive)

Newsgroup: sci.electronics
document_id: 54035
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: How to the disks copy protected.

In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu  
(Kuo-Sheng (Kasey) Chang) writes:
> 
> There are several types of copy protection, and the point is to make  
sure the
> user is using a legitimate copy.  The simplest and virtually fool-proof  
way is
> for the program to somehow fixate itself to the machine it was installed  
on
> (some sort of checksum, serial number, whatever) so a copy put on a  
different
> machine (NOT installed from original disks) will not work.  
> 

Okay, so what do you do if some part of the machine (presumably the part  
on which the code number or whatever that the program has fixated itself  
upon goes bad, you replace that part, and now your program won't run  
because it's on a "different" computer???

This is, of course, assuming that the program uses something in ROM (like  
the BIOS serial number, maybe?) and not a disk-based code number.   
Obviously if the drive goes bad you'll be reinstalling the stuff anyway.

I work in a computer lab which is part of the university microlab system.   
We have the wonderfully fun task of maintaining well over a hundred  
machines, both PC and Macintosh, as well as administering a network of  
over 50 NeXT machines.  I personally am concerned only with a small lab  
with ten PC's and ten Mac's.  (I'm not the manager, but help him with  
admin often).  IMHO, copy-protection schemes of ANY sort are nothing more  
than a major headache for the legitimate user.  Anyone who wants a copy of  
your program and doesn't care about legality will get a copy.  Period.   
"Pirate board" or no pirate board.  I too have "friends" who blatantly and  
quite successfuly "hack" copy protection schemes practically in their  
sleep.

Let's consider what goes on in our lab.  Almost daily we have at least one  
machine down, sometimes several, due to some goofball screwing up some  
setting or other on a piece of software.  Admittedly, we (being students,  
mostly) are not the world's most efficient and effective network  
administrators, but we try.  Keeping even the twenty machines that are  
(partly) my responsibility even vaguely looking and "acting" similar to  
the average user, and maintaining "behind-the-scenes" consistency is a  
real headache, but not so bad a headache as trying to remember twenty  
different folder locations of Norton Utilities when some guy trashes his  
disk.

Often we have hardware problems at peak "business" times and have to do  
some parts-swapping to get stuff working temporarily. . . .

Well, I'll cut to the chase and quit boring y'all . . ..

The point is, often we have to re-install software and copy configuration  
files etc. from machine to machine.  By far the easiest way we have found  
to do this is to get ONE machine working EXACTLY the way we want to, then  
COPY the complete setup of this machine to the other nine (of that  
machine's type).  This ensures us that (for at least ten minutes) we have  
ten IDENTICAL machines to work with.  Having them networked simplifies  
this considerably, as our major packages (WordPerfect, Windows, etc.) are  
all network versions and thus only one copy to mess with.

Often, however, we need to install a package requested by some instructor  
to one, some, or all of the machines for a special project.  This is  
usually a hand-written or shareware,etc. program similar to what I believe  
the original poster was asking about.  The few we have had with "copy  
protection" schemes have caused nothing but NIGHTMARES for us to maintain  
 . .

In short, don't waste your time with a copy protection scheme.  It's sort  
of like outlawing guns.  The criminals will get your program anyway, and  
you will only be hurting the legitimate, honest user.  Write a good user's  
guide and tech manual, whatever else for your program (PLEASE do this  
REGARDLESS of whether you copy protect the thing!!!), and only distribute  
the manual to LICENSED users.  Jack the price to cut your losses, but  
please take a cue from the major companies (who can admittedly afford the  
costs of illegal copies far better than you) and don't burden the  
legitimate user with a "copy protection" scheme!


Sorry for the tirade, but it's been a long day here . . .. :-)


Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu




> The program is definitely backupable, if restored to the same machine  
(depends
> on the programmer...  don't use a disk drive characteristic!)  If the  
user 
> did an upgrade to the machine, he/she should reinstall all programs any  
way.
> No document look-up, no disk wear-and-tear!
> 
> I did not say that the originals would allow only one install.  The  
user's 
> conscience should do that.
> 
> I know, I'll get flamed for this...  But with the increasing number of  
"casual"
> users who either unknowingly or don't care about the software copyrights
> (It's the truth.  I have "friends" who ask me for copies of my latest  
games
> all the time, and when I refused, they went after somebody else.),  
casual
> pirating is becoming more of a problem.  Some sort of copy protection  
will
> discourage the casual copying.  I've seen what some of my "friends" dug  
up
> somewhere...  Latest and the greatest games, all cracked, WITHIN days of  
actual
> release!  You know how many bytes you need to change in X-wing to  
disable
> the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)   
Determined
> pirates are unstoppable, given enough time, but their results do not  
spread 
> that far, since pirate boards are not that well-known, and easily  
tracked once
> found by authorities.  It is the "casual" pirates that the copy  
protection is
> determined to discourage.
> 
> What I believe the companies should do is implement the above plus
> a special patch once the user registers that loudly exclaims upon bootup
> "REGISTERED TO XXXXX -- address, city, state zip" and disables the  
above.
> Two benefits: 1) encourages registration, 2) cuts down on pirating and
> makes it more traceable, because if the patch's registration message is
> encrypted, it will be quite hard to change, and therefore provides a
> stable trail of who allowed their copy out of their hands, and thus
> violated their license agreement.
> 
> This way, the legitimate users who does not register will experience  
minimal 
> discomfort (who does major upgrades to their computer frequently?) as  
only
> problem they have is they won't be able to restore to another computer.
> 
> The registered users would have proven they are legitmate users and  
therefore
> gains full rights, and can restore to different machines.  On the other  
hand,
> the software company now have a record of where THIS particular copy is 
> supposed to be.  If this user's copy was found to be somewhere it was  
not 
> supposed to be, we know who has broken their license agreement.  Of  
course,
> a hacker can break that eventually, but that's not the point, is it?
> 
> --Kasey Chang

Newsgroup: sci.electronics
document_id: 54036
From: lsg001@cck.coventry.ac.uk (Graham Wilson)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr21.170932.18356@news.columbia.edu> kn1@cunixa.cc.columbia.edu (Kimball Ng) writes:
>kolstad@cae.wisc.edu (Joel Kolstad) writes:
>
>>One other thing... there are bubblejets, and then there are BubbleJets.
>>There are a few bubblejets out there that produce rather mediocre output
>>(such as HP's dinky little BubbleJet), whereas most produce really good
>>looking output (such as HP's DeskJets).  IBM and Canon both produce some of
>>the really good style bubblejets.


** I am considering either an inkjet or bubble jet printer. I've seen
   inkjet printers and I was impressed with the near lazer quality.

   I have heard a lot of bad things about the cheaper bubble-jet printers.
   Does the ink smudge very easily and take a long time to dry ?

   Thanks.


   
-- 
          T 3/4 c2 l1(s) hbl d- a w+ c- y e++ g f t+ k++ s++ m1+
         *      Graham Wilson      *  lsg001@cck.coventry.ac.uk  *
         *     LL.B.  Law  III     *     Coventry  University    *
          S8  b+  g-  l--  y+  z/   n--  o++  x+  a-  u+  v-  j++

Newsgroup: sci.electronics
document_id: 54037
From: cohen@GOMEZ.phys.virginia.edu
Subject: MOV advice please?

Hello,

Can somebody tell me what kind of MOV's are most useful for a computer
surge protector?  Radio Shack have 2 types, both rated 130V, one for
a 10A current and the other for 20A.  On the other hand, commercial surge
protectors I have seen claim a clamping voltage of 330V-400V, which SEEMS to
me in imply a rated voltage of about 250V (250V * SQRT(2.)=353).

What is the right kind?

While at it, ow important is really the EMI/RFI module?  Is there really any
noticable level of such noise in the power line?

Please-  E-MAIL to me, as this group has too much volume for me to be able
to follow.

Thanks!


Newsgroup: sci.electronics
document_id: 54038
From: tomc@cirrus.com (Tom Crawford)
Subject: Re: what to do with old 256k SIMMs?

In <1r3mmnINN4p1@master.cs.rose-hulman.edu> henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley) writes:

>In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason  
>Haines) writes:
>> 
>> 	I was wondering if people had any good uses for old
>> 256k SIMMs.  I have a bunch of them for the Apple Mac
>> and I know lots of other people do to.  I have tried to
>> sell them but have gotten NO interest.
>> 
>> 	So, if you have an inovative use (or want to buy
>> some SIMMs  8-) )
>Sure I'll give you 10 bucks for all of them

I think they are really neat to put onto key rings.  When somebody
makes the mistake of asking about it, you can *totally* geek out.

tc

Newsgroup: sci.electronics
document_id: 54039
From: mkrajci@wilkes1.wilkes.edu (Martin K.)
Subject: Tunnel diodes on I-G SPICE


Does anybody have an idea how to model a tunnel diode on SPICE?
Thank you.

Martin Krajci mkrajci@wilkes1.wilkes.edu

Newsgroup: sci.electronics
document_id: 54040
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Power, signal surges in home...

In article <1993Apr21.025500.8804@porthos.cc.bellcore.com>  
patter@dasher.cc.bellcore.com (patterson,george r) writes:
> In article <1993Apr20.232804.24632@mprgate.mpr.ca>  
vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
> >kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
> >
> >>My car, unfortunately, has so much computer junk under the hood that  
it's
> >>astonishingly sensitive to RFI.  
> >
> >Hmmmmm... this has possibilities:
> >If the police are in pursuit of a vehicle, maybe they can bombard it  
with
> >high energy RFI.  :-)
> 
> Right. So all the cops will be buying antique muscle cars for chase  
cars;
> otherwise the *police* cars will die too!

I wonder if you could focus the RFI "gun" so the cops wouldn't have this  
problem???

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
document_id: 54041
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Radar detector DETECTORS?

In article <C5usK6.H2H@athena.cs.uga.edu> mcovingt@aisun1.ai.uga.edu  
(Michael Covington) writes:
> There is or was a microwave tower next to Florida's Turnpike, and you
> could watch the cars hit the breaks as they came in sight of it every
> morning...
> 

Funny . . . I and most of the detector-owning friends I have, are  
generally able to *REMEMBER* such things as nearby microwave towers and  
radar detectors going off in EXACTLY the same spon EVERY DAY . . ..

I know on I-64 at the Grayson, KY exit, there's a store just off the side  
of the road (think it's a Liquor store . . .) with what must be a security  
system that would make most federal prisons proud.  It's the only thing  
I've ever driven by (besides a cop) that puts my Whistler in "Oh my God  
he's Right Behind You!!!!" mode . . ..  I simply ignore the detector and  
use my eyes when I drive by that store . . . 40 seconds later, all's quiet  
on the front and no problem.


:-) :-)

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
document_id: 54042
From: noeler@xanth.CS.ORST.EDU (Eric Richard Noel)
Subject: Re: How to the disks copy protected.

>
>>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>>pose: to keep the honest buyer from making (legal) backup copies. It will
>>definitely not stop any pirates. If you want to protect you soft, supply a
>>good documentation and support. This is IMHO the *only* way of effectively pro
>>tecting software.
>>Best Regards,
>>Arno

I strongly disagree. I think most pirating is done by amateurs, who won't
copy the program if "diskcopy" can't do it.
If you're talking a 20% max goal of pirated copies, I bet that anything that
will beat diskcopy, and can't be easily copied from a hard drive, will
suffice.
I hate hard copy manuals, and would rather have all docs online - *not*
because I want to copy the program, but because its usually faster and
and convenient than sifting through an old book I can't find.

Off deeper end-> Why does everyone think they need to be able to make a 
backup copy? Almost all new software must be installed to the hard disk,
so you are left with the originals as your backups. I think its a waste
of time, space, and money, as well as it makes it to tempting to "lend"
out the backups. 


No flames intended - just my thoughts.

Eric

Newsgroup: sci.electronics
document_id: 54043
From: lsg001@cck.coventry.ac.uk (Graham Wilson)
Subject: Contracts


** For my computer law module I have been asked to write a computer 
   contract for the supply of computer software to a business. The
   software is being especially written for the company.

   Would anyone, per chance happen to have a copy of a computer
   contract on their system which they could mail me.

   If anyone has a computer contract but it contains sensitive 
   material then I can assure them that it will remain confidential
   and I will not pass it on, or allow anyone else to view it.

   Thanks.




-- 
          T 3/4 c2 l1(s) hbl d- a w+ c- y e++ g f t+ k++ s++ m1+
         *      Graham Wilson      *  lsg001@cck.coventry.ac.uk  *
         *     LL.B.  Law  III     *     Coventry  University    *
          S8  b+  g-  l--  y+  z/   n--  o++  x+  a-  u+  v-  j++

Newsgroup: sci.electronics
document_id: 54044
From: cph@dmu.ac.uk (Chris Hand)
Subject: Re: Lead Acid batteries & Concrete?

Carter Ames (camter28@astro.ocis.temple.edu) wrote:
:   Why does a lead acid battery discharge and become dead (totally unuseable)
: when stored on a concrete floor?  

It could be that you stored it somewhere that it could become covered
by moisture or damp air, which would short out the terminals.

The same thing happens to my car (Citroen 2CV) -- damp gets under the
bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.

The solution (for the car) is to clean the plug leads and spray with
WD-40 (moisture repellant).  If damp *is* the problem, then storing the 
battery off the ground may help.  I'm not sure if spraying with WD-40
would be safe since it is very flammable (high percentage petroleum).

Just a thought...

Chris

-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
document_id: 54045
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.
>
>thanks
>camter28@astro.ocis.temple.edu

I am not a battery expert, but from recent reading, a lead acid battery
will self discharge at a relatively high rate, and if stored in a discharged
state, will develop a condition I think is called sulfation.  In storage,
either the electrolyte should be removed and replaced for use (fat chance
I'd ever do that at home), or the battery should be stored on a trickle
charge.  I have also (I think) read that the condition may be reversable
if hooked up to a current limited charging circuit fro a LONG period of time.
The refernce I remember is to use C/50 (where C is the amp hours) as the
charging circuit, and leave it hooked up for weeks.  Some of this may
only apply to Gel type cells, but I suspect the same applies to the liquid
type.

Richard Dell


Newsgroup: sci.electronics
document_id: 54046
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: A question about 120VAC outlet wiring.

In article <1993Apr22.004728.6736@mtu.edu> cmwolf@mtu.edu (Engineer by Day - Asleep by Night) writes:
>Dave Martindale (dave@imax.imax.com) wrote:
>: They require two separate grounds.  One ground goes to the ground pin
>: of the outlet, and the other ground wire is connected to the outlet's
>: mounting tabs (and thus grounds the box and faceplate screw and metal
>: faceplate, if any).
>
>I thought the ground WAS connected to the metal frame on the socket.
>
>-- 
>------------------------------------------------------------------------------
>Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
>------------------------------------------------------------------------------
>         Remember, even if you win the Rat Race - You're still a rat.

Not in isolated ground recepticles (usually an unusual color, such as orange
or yellow) often used in low noise, low leakage applications, as mentioned
earlier in the thread.

Richard Dell


Newsgroup: sci.electronics
document_id: 54047
From: regmad@gsusgi2.gsu.edu (Michael de Kraker)
Subject: Re: Packet Radio on the PC

koberg@spot.Colorado.EDU (Allen Koberg) writes:

>I'm looking for any and all information regarding packet radio
>implementation on the PC.  Software, hardware, whatever.

>Please e-mail any info to koberg@spot.colorado.edu.

>Thanks


	Try rec.radio.packet

 
     _______  ______
    /        /        /       /    Michael A. de Kraker
   /        /______  /       /     Georgia State University  404-651-2390
  /    ___        / /       /      Internet:REGMAD@GSUSGI2.GSU.EDU
 /_______/ ______/ /_______/       BITNET  :REGMAD@GSUVM1  PACKET:KD4FKW@W4QO
 
   To iterate is human, to recurse devine
 

Newsgroup: sci.electronics
document_id: 54048
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Subject: Re: UART needed (really BREAK detect)

In article <alan-210493163447@17.129.12.26> alan@apple.com (Alan Mimms) writes:
>Actually detecting a BREAK is done by watching for a "character" containing
>all zero bits with the framing error resulting from its receipt.  This

True enough, but...

>means that the line stayed in the zero bit state even past the stop bit
>time slot, which basically indicates a BREAK.  There is no special way to
>detect BREAK that I have found other than this -- there's no magic signal
>generated by UARTs, etc.

Zilog SCC:
---------
	RR0[7]:  Break Detect

This is a very popular part, but it has a number of quirks, especially
in HDLC mode.

Signetics 68562 DUSCC:
---------------------
	RSR[2]:  Break Start Detect
	RSR[3]:  Break End Detect

Two of the bits in the Receiver Status Register.  You can enable an interrupt
on either of these bits going high, too.  Also, only one NULL will be put
in the FIFO per break detected.

This is simply the best serial chip I've ever worked with.  _Many_ less
quirks than the SCC, which is IMHO second-best.  (Death to 8250 devices!)

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			One Design to rule them all; one Design to find them.
			One Design to bring them all and in the darkness bind
			them.  In the land of Mediocrity where the PC's lie.

Newsgroup: sci.electronics
document_id: 54049
From: ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar)
Subject: Re: ATARI 2600 Processors

In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>game machine). 

Wrong, it has a 6507.

>The 2600 had some extra ASIC chips that were basically
>modified graphics chips and PIA's for the joysticks. 

It had one custome chip (not an ASIC in the sense that word is now understood):
the TIA (sometimes known as the 6526, although most other manufacturers list
that as the CIA complex interface adapter.)  TIA stands for Television
Interface Adapter, and it handles sound, paddles and the minimal video hardware
the 2600 possessed.

There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
regulator and (if memory serves) a 555 timer.  That's all.

>Later model 2600
>might have incorporated many of the chips into one ASCI, as the weight
>of the machines and part count decreased a lot over the years.

Not according to the servicing documentation I have here.  The 2600 did not
change intenally very much at all.

>Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
>their games. 

ROMS were mapped into the upper 4K of the 6507's address space.  2K and 4K
games were fine, but later 8K and 16K games needed bank switching.  Atari
(and others) made much of these "huge" cartridges.

>I have no idea how much RAM it had to work with, but I
>would hazard a guess of 2 or 4K RAM. 

Wrong, it had 128 bytes of RAM from the RIOT.  This was multiply mapped into
both page 0 (pseudo-registers) and page 1 (stack), and also throughout the
bottom 4K of memory.  TIA registers also sat in this address space.

As 128 bytes of RAM was somewhat limiting, some later cartridges also carried
RAM themselves, which was interesting as Atari had provided no write line
to the cart.  This was managed by mapping the reads from RAM into one address
range, and the writes into another, but all the time this scheme ate into
the *very* scarce ROM address space.

							Ian.

Newsgroup: sci.electronics
document_id: 54050
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Making up odd resistor values required by filters

One way to make cheap trimmable resistors is to use a high-wattage carbon
composition resistor, and saw a notch in it with a triangular file.
Of course, you can only increase the resistance, not decrease it.

Newsgroup: sci.electronics
document_id: 54051
From: ascott@tartarus.uwa.edu.au (Andrew Scott)
Subject: Re: How to the disks copy protected.

cyborg@kauri.vuw.ac.nz (-xivo-Alex Ivopol) writes:

>I believe that persistence overcomes even the very best copy protection
>schemes.

I would expect that CD-ROM software would not even need copy protection.
As the program on a CD-ROM would not fit onto a hard-drive, and it is
impossible for the average (and even not-so-average) user to write to a
CD-ROM, copies of the software (that still work) could never be made.

Hmmm.. now that I think about it.. with a creative TSR, maybe
disk-swapping could be used to simulate files on a single disk. You
would need a tonne of disks though.

>-- 
>Alex T. Ivopol                           cyborg@kauri.vuw.ac.nz
>External User - Victoria University of Wellington - New Zealand
>************* I speak for myself and no one else. *************

Andrew Scott
INTERNET:ascott@tartarus.uwa.edu.au

Newsgroup: sci.electronics
document_id: 54052
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Building a UV flashlight

The simplest and cheapest soft UV bulb is an AR-1 argon bulb (or other argon
bulb).  It works like a neon bulb except it glows purple.  It will cause
stuff to fluoresce.  It requires very little power, just a battery, an
oscillator, and a step-up transformer to about 100 volts.

Electronic Goldmine (602) 451-7454 has several UV lamps, both as pre-built
units and kits.  Ask for their catalog.

Newsgroup: sci.electronics
document_id: 54053
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Subject: Re: Power, signal surges in home...

In article <1r1jmoINN8mb@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Douglas S. Rand) writes:
>>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:

>>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>>   that a ham would be running that kind of power from a car.  Ham rigs

>>Not possible either.  You'd need about a 300 amp alternator for
>>just the amplifier.  I can just see it.  You need to slow
>>down on a downgrade,  so you hit the push to talk button.

>Now, that indeed is possible.  A good friend of mine is running about 1 KW
>PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
>the rig an "electronic brake" since the engine noticeably slows when the
>key is down.

It has been a while since I knew the electronics of ham radio, but I seem
to remember that PeP is actually 4x the "real" power.  Which makes 1KW PeP
actually around 250W.  Or was it 2x?  I disremember.

"Effective transmitted power" is also "odd", in that it takes into account
antenna height and geometry.  Which is why a TV station with a 50KW Klystron
might advertise a megawatt (if their antenna is on the top of the
CN tower ;-).

This is like Sears HP ;-)

Though, 1500 real watts still isn't impossible.  About 125-150A with
a 12V alternator, less if the alternator produces higher voltages.

It's only three horsepower (taking into account inefficiencies).  You'll
feel it when you hit the key.  But not too much.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
Ferret list: ferret-request@ferret.ocunix.on.ca

Newsgroup: sci.electronics
document_id: 54055
From: cstrockb@cs.sunysb.edu (Caleb Strockbine)
Subject: Re: Long distance IR detection

In article <1993Apr22.060607.12380@macc.wisc.edu> jvannes@vms.macc.wisc.edu writes:

   I would also be interested in the application here.  I work with a Dance and
   Technology program, and want to build something to track dancers on a 30 foot
   wide stage from 50 feet away.


Could make for some interesting choreography... light and sound could be 
controlled directly by the position of a dancer on stage, or by the number
of dancers on stage. Neat.

You could even build a spotlight that follows the dancer around on stage!

Can you tell us more about what you're doing? Sounds like a very cool program.

Caleb Strockbine
cstrockb@ic.sunysb.edu

Newsgroup: sci.electronics
document_id: 54056
From: truemner@mac-truemner.rd.hydro.on.ca (Gary Truemner)
Subject: HELP...high data link

I have a couple applications for high speed data links
1__replacement of ultrasonic signal coaxial cables with fiber optic cable
2__applying fiber optic slip ring for 16 channel ultrasonics inspection
system for CANDU reactor inspection
3__remote data link from ultrasonic pipeline inspection device including
transfer of 16 channels via microwave or other higher speed transfer of
ultrasonic data from remote inspection head.

I would be happy to share sources...other info as acquired.
Please mail me or post here.
.....this is a long term upgrade over the next years _+

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  THANKS...... _/_/_/  truemner@mac-truemner.rd.hydro.on.ca     _/  _/
              _/  _/ ONTARIO HYDRO.Automated.NDT&Welding.R&D   _/_/_/
             _/_/_/ (416)207 6380.FAX:237 9285.Toronto.CANADA _/  _/

Newsgroup: sci.electronics
document_id: 54057
From: butts#@shocker.ee.twsu.edu (Ronald W. Butts -SUPER ACCT)
Subject: Re: Need to find out numb

In article <6208.442.uupcb@ozonehole.com> gerald.belton@ozonehole.com (
Gerald Belton)  writes

>Subject: Need to find out numb
>Date: 20 Apr 93 12:18:00 GMT

>AL>There is a number you can call which will return a synthesized
>AL>voice telling you the number of the line.  Unfortunately, for the
>AL>life of me I can't remember what it is. The telephone technicians
>AL>use it all the time.  We used to play around with this in our
>AL>dorm rooms since there were multiple phone lines running between
>AL>rooms.
>
>It probably wouldn't help for you to post the number, since it appears
>to be different in each area.  For what it's worth, in the New Orleans
>area the number is 998-877-6655 (easy to remember, what?)
>
>
> * SLMR 2.1 * Ask me anything: if I don't know, I'll make up something.
>                                          

Here in our city, dialing either 940-7222 (newer exchanges) or 940-2222222 [
sic] will get a synthesized message. Works great for having people call you 
back at unlabeled pay phones.

Regards,
Bill


+------------------------------------+-----------------------------------+
| Ronald W. (Bill) Butts, Jr.        |      Gentlemen! Gentlemen!        |
| Electrical Engineering Department  |    You can't fight in here--      |
| The Wichita State University       |       This is the War Room!       |
| butts@shocker.ee.twsu.edu          |                                   |
+------------------------------------+-----------------------------------+

Newsgroup: sci.electronics
document_id: 54058
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: How to the disks copy protected.

In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
(Eric Richard Noel) writes:
> I hate hard copy manuals, and would rather have all docs online - *not*
> because I want to copy the program, but because its usually faster and
> and convenient than sifting through an old book I can't find.

Just MHO, but I prefer hardcopy books because you can have three or four  
of them open spread across the bed (next to the desk in my dorm) and  
reference them while using the program full-screen.  The Windows Help  
things come closest to good on-line documentation I've seen, but they  
generally aren't detailed enough and would probably take a LARGE amount of  
space (even compressed) which is at a premium on my system . . ..  In  
fact, the manuals are the primary reason I bought Borland's C++ compiler  
instead of using the one the lab licensed (in the lab, of course).  I've  
got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
his own . . . :-)

> 
> Off deeper end-> Why does everyone think they need to be able to make a 
> backup copy? Almost all new software must be installed to the hard disk,
> so you are left with the originals as your backups. I think its a waste
> of time, space, and money, as well as it makes it to tempting to "lend"
> out the backups. 

We've destroyed about six sets of original Microsoft Word for Mac 5.0 and  
Word for Windows (may have been a bad batch of disks).  Don't have the  
faintest idea what happened to them, they just went bad.  Weren't stored  
near any magnetic fields or otherwise mistreated, indeed they were only  
used once.  Given this, and the massive headaches finding a working set of  
disks to fix some of the machines that periodically go down, I'd say  
having working backups is a godsend.  I sure wish we'd had them (Sometimes  
I think Murphy's Law holds true more often than Newton's!!) when we needed  
them.  I think it's sortof like snake antivenin.  99.995% of the time you  
have absolutely no use for it, but when you need it, BOY do you ever need  
it!

I don't have backups of my originals at "home" but then my machine doesn't  
see anywhere NEAR the use/abuse of these here at the lab, and so I  
consider it less of a risk.  Still, I usually make "working copies" of  
them when I install them and then eventually re-use these "working copies"  
for something else. . ..


> 
> 
> No flames intended - just my thoughts.

Just mine, too!  :-)

BTW, before anyone notices my mentioning "copying" programs from machine  
to machine when we do installs here and wonders about the licensing, the  
upper-management (non-student staff, of course) are METICULOUS in checking  
with providers of the software and making SURE we are sticking to the  
license agreements . . ..

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
document_id: 54060
From: acollins@uclink.berkeley.edu (Andy Collins)
Subject: Re: Packet Radio on the PC

In article <regmad.735519580@gsusgi1.gsu.edu> regmad@gsusgi2.gsu.edu (Michael de Kraker) writes:
>koberg@spot.Colorado.EDU (Allen Koberg) writes:
>
>>I'm looking for any and all information regarding packet radio
>>implementation on the PC.  Software, hardware, whatever.
>
>    /        /        /       /    Michael A. de Kraker
[ Question about packet radio deleted ]
>
>   /        /______  /       /     Georgia State University  404-651-2390

How about rec.radio.amateur.packet?  At least at my site, there is no
general packet radio (i.e. non-amateur) newsgroup.

That said, I would definately subscribe to r.r.a.packet if you want to
learn about all aspects of amateur packet radio, at both the high and
low ends.  Also, I would get the FAQ from the group, and then post any
specific questions to that group.  Everything I could tell you is 
probably in the FAQ, and the people who really know what's going on all
seem to be on r.r.a.packet (although they might be here too, you never know :)

Hope it helps...

Andy Collins, KC6YEY
acollins@uclink.berkeley.edu

Newsgroup: sci.electronics
document_id: 54061
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

Radio-Electronics sends each company a bunch of computer-printed address
labels for all the people who circled that company's number.

The company sends whatever it wants to -- normally a catalog.


-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 54062
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.

This topic was beaten to death a year or so ago.

The concrete is not the problem. 

Lead-acid batteries often fail from disuse (not being charged for a long
time), but there's no way the concrete floor could be the cause of the
problem.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
document_id: 54063
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <1r7h1r$o7p@uniwa.uwa.edu.au> ascott@tartarus.uwa.edu.au (Andrew Scott) writes:
>I would expect that CD-ROM software would not even need copy protection.
>As the program on a CD-ROM would not fit onto a hard-drive, and it is
>impossible for the average (and even not-so-average) user to write to a
>CD-ROM, copies of the software (that still work) could never be made.
>
>Hmmm.. now that I think about it.. with a creative TSR, maybe
>disk-swapping could be used to simulate files on a single disk. You
>would need a tonne of disks though.
>
There are many programs on CD-ROM that fit on a harddisk, not all software 
is that big (but we're getting there :-)).

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only ones.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54064
From: john@gu.uwa.edu.au (John West)
Subject: Re: ATARI 2600 Processors

ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:

>In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>>game machine). 

>Wrong, it has a 6507.

For those who would like to know, the 6507 was a 6502 without IRQ or NMI,
and with only 13 address lines (giving 8K memory space).

>It had one custome chip (not an ASIC in the sense that word is now understood):
>the TIA (sometimes known as the 6526, although most other manufacturers list
>that as the CIA complex interface adapter.)  TIA stands for Television
>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>the 2600 possessed.

Didn't know about it being called the 6526 - thats the CIA found in the
Commodore 64 (I don't believe this chip existed when the 2600 was around).
The TIA was mapped into the bottom 128 bytes of page 0, and shadowed in the
bottom 128 bytes of page 1. To get an image on the screen, you had to wait
until the raster line your picture started at, load bitmaps for this line
into the 'sprite' registers, tell them what x positions to take, how many
duplicates you wanted, etc, then do it all again for the next line. This
took all of the processor's time during the visible portion of the
display.

>There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
>regulator and (if memory serves) a 555 timer.  That's all.

The RAM was mapped into the top 128 bytes of page 0, and shadowed in page
1. The 6502 has a zero-page addressing mode on most instructions that is
both shorter and faster than the normal ones, so it is important on a
machine like this to have the scratchpad RAM in page 0. Unfortunately, it
also wants its stack to be in page 1 (the stack pointer is 8 bits, and the
high byte of the address is hardwired to 1).

The IOT section was mapped into page 2 somewhere. 2 8 bit I/O registers
(can't remember if each bit could be independantly set to I or O like the
6522 and 6526), and 1(?) 8(?) bit timer with a programmable prescaler (I
think this was some power of 2). There were no interrupts in the system, so
many games would set up the timer at some known time, go away and do
something else for a while, then sit and wait for the timer to run down.

There was no logic in the box to do address decoding - the RIOT had at
least 2 chip select pins (probably one active high, one active low), and I
imagine the TIA was much the same. Various address lines were fed directly
to chip selects. The 6507 likes to have ROM right at the top of memory, so
the 2600 had to use ROMs with active high chip selects - not exactly
normal, so some cartriges had a 7404 in them to convert this to the more
usual active low chip select.

John West

Newsgroup: sci.electronics
document_id: 54065
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

[byteocide]

>
>What I believe the companies should do is implement the above plus
>a special patch once the user registers that loudly exclaims upon bootup
>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>makes it more traceable, because if the patch's registration message is
>encrypted, it will be quite hard to change, and therefore provides a
>stable trail of who allowed their copy out of their hands, and thus
>violated their license agreement.
>
You take two copies with a different registration id, compare them byte for 
byte and you know where they are located. Usually you will be able to 
find out what is what after that. 

And what keeps me form registering as John Doe from the company Public 
Domain, Yellow Brick Road 1, Tinseltown or something???

>
>--Kasey Chang

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only ones.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54066
From: sl@nessie.mcc.ac.uk (Stuart Lea)
Subject: Anyone build anything interesting with PIC16C5X devices ?


I've just started programming with the PIC16c57 and I'd like talk to similar
like minded people ?  Have you built anything interesting, if so, I'd be
interested in talking about various aspects.

Yes, I already have the application sheets, assembler & simulator.

Cheers,

Stuart

-- 
+-Stuart Lea--Tel:061 200 4809--Fax:061 200 4019---UMIST University-----------+
| JANET   :   sl@uk.ac.mcc.nessie                  B22, Main Bldg., PO Box 88 |
| INTERNET:   sl@nessie.mcc.ac.uk                  Manchester, UK M60 1QD     |
+-----------------"Weather is here, wish you were beautiful"------------------+

Newsgroup: sci.electronics
document_id: 54067
From: ws2@cunixa.cc.columbia.edu (Wayne Sun)
Subject: Looking for NC1 Telecaption Decoder Module

Does any one know where I can get a telecaption decoder module?

Need it to build a close caption decoder.
Thanks.

Wayne


'Wait till finals are over, that is when the fun really begins.'
'Enjoy the sun while its still young and out there.'
'When one dreams of his home town, he is not wishing that everything could
be as it was, but he wishes that he was still young to enjoy it all again.'

Newsgroup: sci.electronics
document_id: 54068
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: Making up odd resistor values required by filters

idh@nessie.mcc.ac.uk (Ian Hawkins) writes:

>When constructing active filters,  odd values of resistor are often required 
>(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
>capacitor values and cope with the strange resistances then demanded).

>Is there a PD program out there that will work out how best to make up such
>a resistance, given fixed resistors of the standard 12 values per decade?.(1,
>1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
>recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
>q and finding prefered values x,y and z.

I once wrote such a program (in BBC basic...) It was very crude, and took
around 5 seconds to do an exhaustive search (with a small amount of 
intelligence), and told you the best combination >Rq and the best below Rq.

If you want to write one, just store the prefered values in an array, and
then search the solution space using three nested loops. I'm sure you
could knock this up in an hour.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
document_id: 54069
From: kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,)
Subject: Why circuit boards are green?

Not that the question is anything important, but I am still curious:
Why is that almost all printed circuit boards are green? I have seen
a few blue ones, but no red, yellow, company logo etc. Is there a
technical reason or could it be that the marketing "geniuses" have
not tought about it (yet)?
--
Juha

Newsgroup: sci.electronics
document_id: 54070
Subject: PCMCIA
From: martin.vuille@synapse.org (Martin Vuille)

Newsgroup: sci.electronics
From: martin.vuille@synapse.org
Subject: PCMCIA

Does anyone know who to contact to obtain a copy of the PCMCIA standard?

Thanks
MV
---
  OLX 2.1 TD  ProControl * Kemptville, ON * 04-22-93 9:34 pm

Newsgroup: sci.electronics
document_id: 54071
Subject: ELECTRONIC DESIGN MAG.
From: martin.vuille@synapse.org (Martin Vuille)

Newsgroup: sci.electronics
From: martin.vuille@synapse.org
Subject: Electronic Design

Does anyone know the telephone number for the circulation department
of 'Electronic Design' magazine?

MV
---
  OLX 2.1 TD  ProControl * Kemptville, ON * 04-22-93 9:35 pm

Newsgroup: sci.electronics
document_id: 54072
From: stephen@dogmatix.inmos.co.uk (Stephen Collyer)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr22.220549.26828@dmu.ac.uk>, cph@dmu.ac.uk (Chris Hand) writes:
|> Carter Ames (camter28@astro.ocis.temple.edu) wrote:
|> :   Why does a lead acid battery discharge and become dead (totally unuseable)
|> : when stored on a concrete floor?  

I think it's because the lead gets coated with lead oxide if the battery is
not being charged or discharged. I remember some advice from an ancient car
manual guide my father had, which was to use car batteries to power a garage
clock or something similar when they're not in a car. This is supposed to 
prevent the oxidation but I've no idea if it really works. The concrete floor
connection is a red herring.

|> 
|> It could be that you stored it somewhere that it could become covered
|> by moisture or damp air, which would short out the terminals.

This may contribute to discharging but would be reversible.
 
|> 
|> The same thing happens to my car (Citroen 2CV) -- damp gets under the
|> bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.
|> 
|> The solution (for the car) is to clean the plug leads and spray with
|> WD-40 (moisture repellant).  If damp *is* the problem, then storing the 

Well, this is off-topic, but back in the days when I used to drive bangers
I never found WD-40 to do anything that wiping with a dry cloth did'nt do.
I think the effectiveness of WD-40 is a myth invented by the guy who owns
the company.

|> battery off the ground may help.  I'm not sure if spraying with WD-40
|> would be safe since it is very flammable (high percentage petroleum).
|> 
|> Just a thought...
|> 
|> Chris
|> 
|> -- 

Steve Collyer.

Newsgroup: sci.electronics
document_id: 54073
From: pjhicks@acri.fr (Peter J. Hicks)
Subject: Re: Lead Acid batteries & Concrete?

In article 3nx@athena.cs.uga.edu, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>>
>>  Why does a lead acid battery discharge and become dead (totally unuseable)
>>when stored on a concrete floor?  
>>  I decided to bring the battery in from the lawn mower and the motorcycle
>>from the unheated garage this year, *to preserve them* and I just
>>went to use them and noticed that not only do they not work, but 
>>they act like the two terminals are shorted.  I asked a friend
>>and he said that you should never do that, 'cause it ruins them,
>>but he couldn't tell me why.
>
>This topic was beaten to death a year or so ago.

It seems to me that the original question was for advice on his problem
not a history lesson - I think that  if this question comes up from time
to time then people should get a civil answer 


>

>The concrete is not the problem. 
>
>Lead-acid batteries often fail from disuse (not being charged for a long
>time), but there's no way the concrete floor could be the cause of the
>problem.

Could ANYONE please explain WHAT happens with a battery and is there any
cure to get it back into life
  
>


>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><





Newsgroup: sci.electronics
document_id: 54074
From: ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar)
Subject: Re: ATARI 2600 Processors

In article <1r847f$kp7@uniwa.uwa.edu.au> john@gu.uwa.edu.au (John West) writes:
>ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:
>>Wrong, it has a 6507.

>For those who would like to know, the 6507 was a 6502 without IRQ or NMI,
>and with only 13 address lines (giving 8K memory space).

Yes, but still not a 6502 for those differences.  Same instruction set,
of course.

>>It had one custom chip (not an ASIC in the sense that word is now understood):
>>the TIA (sometimes known as the 6526, although most other manufacturers list
>>that as the CIA complex interface adapter.)  TIA stands for Television
>>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>>the 2600 possessed.

>Didn't know about it being called the 6526 - thats the CIA found in the
>Commodore 64 (I don't believe this chip existed when the 2600 was around).

Yes, the same number, but an entirely different device.  I should have
qualified this further by stating that this was the PAL version of the TIA -
I am not 100% sure that the NTSC TIA would have a different number.

>The TIA was mapped into the bottom 128 bytes of page 0, and shadowed in the
>bottom 128 bytes of page 1. To get an image on the screen, you had to wait
>until the raster line your picture started at, load bitmaps for this line
>into the 'sprite' registers, tell them what x positions to take, how many
>duplicates you wanted, etc, then do it all again for the next line. This
>took all of the processor's time during the visible portion of the
>display.

Does anyone on the net actually have details of the TIA, as this is the only
device I have not yet discovered details about?  Atari Australia, when asked,
claimed that their attempts to get the programmers documentation for the 2600
had failed, as the US head office had refused to provide it.

>to chip selects. The 6507 likes to have ROM right at the top of memory, so
>the 2600 had to use ROMs with active high chip selects - not exactly
>normal, so some cartriges had a 7404 in them to convert this to the more
>usual active low chip select.

I saw a couple of cheaper devices with PN2222's and a couple of resistors
hooked up as a cheap inverter.  Nasty, but workable, and cheaper than a
7404 inverter if labor costs almost nothing.

							Ian.

Newsgroup: sci.electronics
document_id: 54075
From: thor@e.kth.se
Subject: Looking for Z80-STI (MK3801) by Mostek

Hi,
I am looking an integrated circuits for my Z80-based 
computer.
The circuit is called Z80-STI (Serial Timer Interrupt), 
MK3801, and
made by Mostek. Mostek is called SGS Thompson today.
 
I have been in contact with SGS Thompson, unfortunately 
they me told that Z80-STI is obsolete.
 
So, my question is if anyone know if I can get hold of that 
circuits. Are there any companies that specialize in selling 
circuits that are no longer in production? I have contacted 
several electronic brokers in
Sweden, but without any success. I would appreciate if you 
could give me hint where I should continue looking. Even 
companies in the United States would be fine, since this 
circuit is pretty crucial to me.
 
 
Thanks in advance.
 
 
Thomas Thor
Royal Institute of Technology
Stockholm, Sweden


Newsgroup: sci.electronics
document_id: 54076
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: help me, i'm not clever! (how to make power supply?)

In article <94318@hydra.gatech.EDU> gt4417a@prism.gatech.EDU (SKELTON,JOEL PHILLIP) writes:

>I need to make a power supply that can take input from a 
>cigarette lighter in a car (12v dc) and drive 7.5 volts
>at up to 3.0 amps. I know enough to know that a simple
>voltage divider with two resistors won't do it right. Can
>such a thing be made from Radio-Shack-able parts without
>too much difficulty?

>jps
>bf

>p.s. I've looked for premade things like this at radio shack but
>none of it seems to go any higher than about 800mA.


>-- 
>Joel Skelton   --    North Avenue Trade School, Dept. of Round Things
>gt4417a@prism.gatech.edu   (ask for Scooter Technologies, and receive)

See if Radio Shack has a National Semiconductor Adjustable Voltage 
Regulator, (National) part number: LM350T or LM350K.  These devices are 
rated for an input to output differential of up to 35 Volts @ 3 Amps.

Digi-Key Corp. has these parts, as well as several other useful regulators.
If you don't have their catalog, their phone number is: 1-800-344-4539.

I can only guess that you may intend to recharge a 7.5 VDC nicad battery 
with this device, and if I'm right, you may want to look through some of the 
hobbiest books to get various ideas for battery charging circuits, first.

If you get stuck, e-mail me your FAX number, if you have one, and I'll send 
you some suggestions or schematics.

e-mail: willisw@coe-nw.clemson.edu



Newsgroup: sci.electronics
document_id: 54077
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: How to the disks copy protected.

In article <C5x75A.48H@ms.uky.edu> msunde01@mik.uky.edu writes:
>In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
>(Eric Richard Noel) writes:
>> I hate hard copy manuals, and would rather have all docs online - *not*
>> because I want to copy the program, but because its usually faster and
>> and convenient than sifting through an old book I can't find.
>
>Just MHO, but I prefer hardcopy books because you can have three or four  
>of them open spread across the bed (next to the desk in my dorm) and  
>reference them while using the program full-screen.  The Windows Help  
>things come closest to good on-line documentation I've seen, but they  
>generally aren't detailed enough and would probably take a LARGE amount of  
>space (even compressed) which is at a premium on my system . . ..  In  
>fact, the manuals are the primary reason I bought Borland's C++ compiler  
>instead of using the one the lab licensed (in the lab, of course).  I've  
>got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
>his own . . . :-)
>

Agree 100%, personally I cannot flip from page to page on a screen and
retain information as easily as in the written page.

>> 
>> Off deeper end-> Why does everyone think they need to be able to make a 
>> backup copy? Almost all new software must be installed to the hard disk,
>> so you are left with the originals as your backups. I think its a waste
>> of time, space, and money, as well as it makes it to tempting to "lend"
>> out the backups. 
>
>We've destroyed about six sets of original Microsoft Word for Mac 5.0 and  
>Word for Windows (may have been a bad batch of disks).  Don't have the  
>faintest idea what happened to them, they just went bad.  Weren't stored  
>near any magnetic fields or otherwise mistreated, indeed they were only  
>used once.  Given this, and the massive headaches finding a working set of  
>disks to fix some of the machines that periodically go down, I'd say  
>having working backups is a godsend.  I sure wish we'd had them (Sometimes  
>I think Murphy's Law holds true more often than Newton's!!) when we needed  
>them.  I think it's sortof like snake antivenin.  99.995% of the time you  
>have absolutely no use for it, but when you need it, BOY do you ever need  
>it!
>

Ditto's ... in fact .. at work, where things are dead if the backup
is no good, I insist on having at least a 2 level backup system.  
It seems that whenever you have 2 good backups, you never need them, 
but if you don't have them, Murphy guarantees that you'll suffer for it.

>I don't have backups of my originals at "home" but then my machine doesn't  
>see anywhere NEAR the use/abuse of these here at the lab, and so I  
>consider it less of a risk.  Still, I usually make "working copies" of  
>them when I install them and then eventually re-use these "working copies"  
>for something else. . ..
>
>
>> 
>> 
>> No flames intended - just my thoughts.
>
>Just mine, too!  :-)
>

 and mine of course.

Richard Dell

Newsgroup: sci.electronics
document_id: 54078
From: sasrer@unx.sas.com (Rodney Radford)
Subject: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

stephen@dogmatix.inmos.co.uk (Stephen Collyer) writes:
>|> The same thing happens to my car (Citroen 2CV) -- damp gets under the
>|> bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.
>|> 
>|> The solution (for the car) is to clean the plug leads and spray with
>|> WD-40 (moisture repellant).  If damp *is* the problem, then storing the 

>Well, this is off-topic, but back in the days when I used to drive bangers
>I never found WD-40 to do anything that wiping with a dry cloth did'nt do.
>I think the effectiveness of WD-40 is a myth invented by the guy who owns
>the company.

Back in high school I used to work for a detailing company, and one of the
services we offered was an engine cleaning (remove all that oil BEFORE you
sell the car...  ;-}). Unfortunately, we did not have a high pressure
washer so we would use one several miles from the shop. On more than one
occasion after washing the engine, it would not start as water would have
gotten under the distributor (I would put a plastic bag around it to try and
minimize this), around the spark plug wires, etc and it would be nearly
IMPOSSIBLE to try and wipe all these areas down with a dry rag. The usual
solution was to carry a can of WD-40, and when the car wouldn't start to spray
all the likely areas and it would then start on the very first time.

It may be a myth, but it certainly kept me from being stranded at a car wash...

--
---
Rodney Radford          || Computer Graphics/Imaging
sasrer@unx.sas.com      || SAS Institute, Inc.
(919) 677-8000 x7703    || Cary, NC  27513


Newsgroup: sci.electronics
document_id: 54079
From: mcole@spock (COLE)
Subject: microstepping

Does anyone know where to get a schematic for a micro stepping circuit?
Any help would be appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
document_id: 54080
From: mcole@spock (COLE)
Subject: HM8350 or HM8348

I have some MICE that have a chip numbered HM8348 and HM8350.  I have not  
been able to find information on these.  Any help would be appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
document_id: 54081
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Switching PS questions


	Greetings. I've recently decided to chuck the linear regulators
	and learn the "black magic" art of switching power supplies...
	(before anyone flames me, I KNOW, both have their place :-)

	Anyways, I've built the basic up & down converters with pretty
	good results (>80% efficiency) but I'm running into problems
	when I try to design & build anything that puts out serious
	amps... I know it can be done (I have some 5V@200A guts on my
	bench) but something puzzles me: I'm using a simple choke as 
	the storage element (basicly a toroid with a single winding)
	but ALL commercial models use transformers with MANY windings.
	I traced a few and they seem to use some of the winding for
	the usual error/feedback but some of the others seem to loose
	me... What are they for? Better than that, anyone have a full
	schematic for one of these that I could get a copy of? I'd
	love to see how they manage to squeeze out so much from such
	low volume :-)

	My other problems (in getting high amps & good efficiency) are
	1) Lack of sources of ideal components (calculated) and 2)
	Limited knowledge of the whole topic... I'm doing this on my
	own (not school) mind you (in fact, I have yet to take any
	course that covers transistors ;-)

	So, is the answer to #1 the accumulation of dead commercial
	models and truning into a scavanger (not that it's not what
	I'm doing now...) and #2 getting & understanding schematics
	and a bit more of the [mind-boggling] theory? 

	Take care.

	P.S. My goal is 12V @ ~25A in (car battery) -> 250VAC out and
	(on the other end) 250V -> +5VDC @ 5A, -5V @ 1A, +12VDC @8A
	and -12VDC @1A... the distance between the two will be
	more than 100 feet (of 14-16 gauge) but less than 300 feet.
	Would like to have a working model in a year or so... :-) 
	(Do I have a chance to make it?)
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
document_id: 54082
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Lead Acid batteries & Concrete?

Michael Covington (mcovingt@aisun3.ai.uga.edu) wrote:

: This topic was beaten to death a year or so ago.

: The concrete is not the problem. 

: Lead-acid batteries often fail from disuse (not being charged for a long
: time), but there's no way the concrete floor could be the cause of the
: problem.

Ditto. The only remote, and I do say remote, possibility is that if the
ground was REAL cold (< -30F) the battery might freeze an split. But then
it would probably freeze anyway :-)

        Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
document_id: 54083
From: derry@NeXTwork.Rose-Hulman.Edu (John Derry)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu>  
camter28@astro.ocis.temple.edu (Carter Ames) writes:
> 
>    I was just wondering one thing, actually two. ( I hope that this is  
the
> proper place to post this subject)
> 
>   Why does a lead acid battery discharge and become dead (totally  
unuseable)
> when stored on a concrete floor?  
>   I decided to bring the battery in from the lawn mower and the  
motorcycle
> from the unheated garage this year, *to preserve them* and I just
> went to use them and noticed that not only do they not work, but 
> they act like the two terminals are shorted.  I asked a friend
> and he said that you should never do that, 'cause it ruins them,
> but he couldn't tell me why.
> 
> thanks
> camter28@astro.ocis.temple.edu


What happens is that (I heard this discussed on "Northern Exposure") there  
is a molecular juxtaposition of the molecules in the battery and the  
molecules in the concrete.  This acts as an attractant to UFOs (actually  
their crew members) and they arrive at the scene of the battery/concrete  
combination.

Then they proceed to SUCK ALL THE ENERGY OUT OF THE BATTERIES!

Remedy:  Set the battery on a nonconcrete floor.

Jack

Newsgroup: sci.electronics
document_id: 54084
From: simon@sco.COM (Simon Tooke)
Subject: CALLER-ID chip info requested

I just got caller-id (except Bell calls it "call display" and didn't know
what I was talking about when I asked for "caller-id").  I got the
cheapest display box I could find, and hope to convert it to serial out.

The chip used is an 18-pin DIP marked "CDT 14-285" and "1473 9220".
I presume the 9220 is the date.

I'm hoping somebody out there knows something about this chip, to save
me a very strange few hours hooked up to a scope, asking my friends to
call me again and again.

I'll post any interesting replies, and my experiences.

-simon tooke

simon@sco.com



Newsgroup: sci.electronics
document_id: 54085
From: skelly@amiganet.chi.il.us (Sean Kelly)
Subject: Pin-out for 27C64??

 
 
     Does anyone know the pin-outs for the 27C512 EPROM??  I have bought
several of them, none of which has come with the pin-outs!  Any info would be
appreciated....

%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
%   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
%   Always looking for classic video games for the following systems:   %
%                                                                       %
%  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Newsgroup: sci.electronics
document_id: 54086
From: skelly@amiganet.chi.il.us (Sean Kelly)
Subject: Question on addressing...

 
 
     I have a question about accessing certain addresses on a chip,
particulary a 27C512 EPROM.  Although I don't know that much about it, as I
understand it, there's a pin on the chip that, when voltage is applied, kicks
up the address.  The question is how do you determine how many bytes the
address is incremented by??  For example, if I have code I want to be
accessed at $2000 and also at say $4000 how do I move the address pointer to
those positions??  Thanks for any info...

%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
%   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
%   Always looking for classic video games for the following systems:   %
%                                                                       %
%  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Newsgroup: sci.electronics
document_id: 54087
From: gfl@herahera.cc.bellcore.com (lenahan,grant f)
Subject: Re: Adcom cheap products?

Much deleted about assembly in USA vs. other, 
I wish to focus on the subject of warm-running amplifiers:

> : >  Sure the amp runs very fairly
> : >  hot - but that's how you get an amp to sound incredibly good.
> 
> : An amp that runs hot has no bearing on how it's gonna sound.
> : The amp you have probably is running Class-A the whole day.
> 
> : because either the engineer or manufacturer of that amp wanted
> : to skimp on heatsinking or cooling to save costs!  Hmmmmm....
> 

There is a correclation between warm-running amps and good sound,
or in your words, "it DOES have a bearing on....".

Now, I don't suggest that everyone run out and create combination
stove/amplifiers that will degrade lifespan,
but a cold-running circuit is much more suceptible to temperature
variation with varrying current than is a warm-running one.  And since
junction resistance is a function of temperature, this has a detrimental
effect on linearity.  

a few facts:
-bias points vary with temperature
-junction resist varrie with temp
-Adcom products do NOT run class-A

If you still don't beleive this assertion, consider the warm-up requirements
for most good test equipment, or better yet, just listen to an amplifier
warm-up.  On many designs its quite audible, on mine, about 20 minutes for
the output stage, many hours for the drivers.  Fortunately the drivers
are not switched.

In any experiment, or when drawing conclusions from listening,
betcareful to seperate the effect of device temperature from bias
(idle current) level.  Both have a positive correlation with low
distortion and "good" sound quality, and high bias results in
warmer operation, all other factors being equal.

Grant



Newsgroup: sci.electronics
document_id: 54088
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu>, billq@ms.uky.edu (Billy Quinn) writes:
|> I built a little project using the radio shack 5vdc relays to switch
|> audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
|> most of the common things one is supposed to do when using relays and
|> nothing seemed to get rid of the clicks.
|> 
|> My question is:
|> 
|> 	Is there a good relay/relay circuit that I can use for switching
|> audio, so that there will be *NO* noise of any kind on the audio lines.
|> 
|> I will appreciate any advice or references to advice.  Also, exact part
|> numbers/company names etc. for the relays will help!

The first step is to make sure that there is no DC component, intentional
or not, on the audio lines to be switched. If neither the output or
input presents an unintentional DC level (let's say they're capacitively
coupled), then putting a 22 K resistor from each input to ground, and
from the output to ground is a good precaution against leakage in any
coupling caps presenting a DC level that is GUARANTEED to cause a click.

If the device presents an unintentional DC level that is from more than
just coupling capacitor leakage, then you need to remove the DC before
switching with coupling capacitors of your own.

If you have more than one relay (each relay switching one input
through to a common output), you can use make-before-break switching
where for a brief instant both sources are connected during a switch
change. This may mask the switch click.

An audio switch that is clickless is made by taking a light bulb and
making your own ersatz opto-isolator with a light-dependent resistor (LDR)
sealed inside a piece of black heatshrink. Many broadcast consoles
use this older, but time-honored technique. Claro actually makes
a complete optisolator like this, but I don't have a part number handy.
Radio Shack has a LDR grab-bag (276-1657) you might want to try.

For a simple, solid state clickless switch that is cheap, you might try 
looking at the CD4066 analog switch that is commonly available (or its
older predecessor, the 4016). Again, the DC component must be removed
prior to switching. Other alternatives include JFET switches (both discrete
and IC) and diode switching (which works relatively well, surprisingly).
All the above, with their pitfalls and application tips could easily
make a subject for a multi-page article.

Solid state switches may induce a click of their own when turned on
due to charge being injected into the audio line through device
capacitance when the control signal changes state. Techniques to
minimize this include lowering the impedance of the signal paths through
the switch, differential switching, and slowing the risetime of the
control pulse. With the 4016, cutting the click can be as simple as
putting 10K - 47K resistors in series with the control pins.

Hope this helps at least get you started.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 54089
Subject: Re: How to the disks copy protected.
From: sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen)

Kuo-Sheng (Kasey) Chang (kschang@sfsuvax1.sfsu.edu) wrote:
> The program is definitely backupable, if restored to the same machine (depends
> on the programmer...  don't use a disk drive characteristic!)  If the user 
> did an upgrade to the machine, he/she should reinstall all programs any way.
> No document look-up, no disk wear-and-tear!

	This is not a good idea.. I upgraded my motherboard last fall.  I
would have been quite pissed at any software that would have forced me to
reinstall simply because I changed motherboards.

	Any info in the BIOS is too volatile to use as a checksum.  Are you
going to require that a user re-install all their software if they add 4Mb
of RAM to their computer?  I did that a couple of weeks ago.  It's in the
BIOS, and if software had told me "this isn't the machine you installed me
on" I would never have used that software again.  Really bad idea.

> I did not say that the originals would allow only one install.  The user's 
> conscience should do that.

	This is silly.  It's much easier to loan disks to a friend and let
them do an install than to backup your copy already on disk, and then give
them that.  Your scheme isn't going to stop anyone.

> You know how many bytes you need to change in X-wing to disable
> the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)

	Do you know any assembly language at all?  All anyone needs to do if
find the part of the code that does the quiz, and insert a JMP instruction
to just completely skip it.  Not that difficult, really!  And there is very
little that commpanies can do to stop this type of thing.  Using PKLITE or
some similar utility would help, but only if the resulting compressed .EXE
were tagged as uncompressable.

> What I believe the companies should do is implement the above plus
> a special patch once the user registers that loudly exclaims upon bootup
> "REGISTERED TO XXXXX -- address, city, state zip" and disables the above.

	This is by far the best idea you presented in your post.  Making it
plainly obvious who registered is going to stop casual pirates. But, the
determined ones are just going to answer "Joe Blow" to the question of
"what's your name" so this won't stop them in the long run.

	Pirates are always going to win this fight.  They simply have more
time to work on the software and figure out the protection scheme.

--
Steve Madsen
sjmadsen@nextsrv.cas.muohio.edu

Ask me about Linux, the free 386 unix!

Newsgroup: sci.electronics
document_id: 54090
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <rcstage1.128.735548462@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:
>In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>[byteocide]

>>What I believe the companies should do is implement the above plus
>>a special patch once the user registers that loudly exclaims upon bootup
>>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>>makes it more traceable, because if the patch's registration message is
>>encrypted, it will be quite hard to change, and therefore provides a
>>stable trail of who allowed their copy out of their hands, and thus
>>violated their license agreement.
>>
>You take two copies with a different registration id, compare them byte for 
>byte and you know where they are located. Usually you will be able to 
>find out what is what after that. 

Probably, but the point is THE COMPANY make the registration patch, NOT
YOU.  Sure, you can probably find another registerred user and compare notes,
but WHY?  It's not hindering you in any way unless you are just hacking.
[Problem about people who cut TOO MUCH from quoting...]

>And what keeps me form registering as John Doe from the company Public 
>Domain, Yellow Brick Road 1, Tinseltown or something???

Nothing, but if you read my WHOLE suggestion, I'm saying that you register
via MAIL by mailing in your registration card, THEN the company send you
the patch which includes the info you put on the registration card.

--Kasey Chang

Newsgroup: sci.electronics
document_id: 54091
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Need help with video detection circuit

verity@jack.sns.com (Steve Verity) writes:

> 
> 
> I am trying to build a circuit that detects the presence of video (Vs.
> a blank screen) by monitoring the R,G, and B outputs of a graphics
> card.  It should be able to detect the presence of a single pixel at
> 65 MHz, which would mean detecting a 15 NS pulse.  It should also be
> able to tell the difference between a blank screen (about 300 mv)
> and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
> cheap.  
> 
> My first circuit was a dismal failure.  I used 3 compariators; each
> compariator had the + input going to one of the guns, the - input
> went to a reference created by a voltage divider(a potentiometer).
> 
> The first problem was that the compariator was way too slow.. I
> needed to get several pixels in a row before it would fire the
> compariators, so I could have a whole screen full of text, but my
> 
> The second problem is that there was more noise on the reference then
> the smallest difference between a blank screen and a dim screen.  In
> fact the difference between completely black and completely white is
> only 650 mv.  I am wondering if I am going to have to amplify the
> video signals to make this work.  
> 
> There are faster compariators, but they are expensive, and require 
> split supplies.   I would need to replace my .49 quad compariator
> with three 1.89 compariators, and create a whole new power supply
> circuit.  
> 
> At this point, I think what I need is some sort of transistor
> circuit.  Transistors are fast and cheap and should do the trick...
> 
> Unfortunately, I am way out of my league when It comes to designing
> transistor circuits, so I am appealing to the net for help.  Any
> ideas, tips, circuits, pointers, references, etc. would be greatly
> appreciated.  
> 
> Oh yes, I only sample the output of this thing every second or so, so
> I don't need a fast response time at all, however, I haven't found a
> way to take advantage of that fact.
> 
> Thanks a lot for any help anybody might be able to give. Of course,
> you will have my undying gratitude.
> 
> 
> Steve Verity
> 
> 
> 
> 
> -- 
> ..........>.........>........>......>...>...>..>..>..>..>.>.>.>>>>>>>>+ .   
> Steve Verity                  +   +             ...Maxed on MIDI        + .
>                                     +      verity@jack.sns.com      + ..   +

IN ORDER to get the 15 nS response time you need, you are better off 
going to an ECL slicer which can run off a single +5 or -5.2 V supply, 
you just need to bias or do some level shifting perhaps to get it in the 
range. Check out the ECL 10K books for a simple cheap solution.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54092
From: gcarter@infoserv.com (George Carter)
Subject: Re: Does someone know what is the news group for IEEE.

In <1993Apr19.192953.22874@usl.edu> yxy4145@ucs.usl.edu (Yu Yingbin) writes:
>       yxy4145@usl.edu     Thanks a lot.

ieee.general

and

ieee.announce


are the most frequently used groups.

Newsgroup: sci.electronics
document_id: 54093
From: UC532838@mizzou1.missouri.edu (handy)
Subject: info wanted about standard phone line

greetings..
I'm a novice in this area. I'm trying to gather info. on standard
phone line settings.
quick questions :
      > if I just want to send out a beep over the phone lines,
        can I do it with some function generator & tie it up to
        one of those phone wires ??
      > which one of those wires should I connect to my DTMF chip
        as AUDIO IN ??
 
any help would be much appreciated..
 
Thankx in advance - Handy Trisakti
                    uc532838@mizzou1.missouri.edu

Newsgroup: sci.electronics
document_id: 54094
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Voltage regulation and current limiting

acollins@uclink.berkeley.edu (Andy Collins) writes:

> One not-so-quick question to throw out there for you guys...
> 
> For our class project, we need to design and build a power supply
> to the following specs:
> 
> Voltatge:  adjustable from 1-12V
> Current:   *limited* at 1A
> 
> Voltage must stay within 2% of designated value for I from 0-1A
> AC ripple less than 5 mV (rms)
> 
> Of course, we can't just use an adjustable voltage, current-limiting
> regulator chip ;^)
> 
> Our problem is with the current limiting (i.e. we've found stuff to
> do the rest of the parts of the circuit).  What the supply must do,
> if presented with a load which would draw more than 1A, given the
> supply voltage, is reduce the voltage so that the current will equal
> one amp.  Thus, if we were to short the thing with the ammeter, we
> should read one amp.  If we measure the current through a 1 ohm 
> resistor at 12V, we should read one amp (and the output voltage, by
> necessity, must be 1V.
> 
> The only basic idea we have seen for the current limiter involves
> a circuit which will pull current off of the base of the output 
> power transistor, and therefore reduce the output.
> 
> So, does anybody have any ideas we could work from?
> 
> Thanks in advance.
> 
> Andy Collins, KC6YEY
> acollins@uclink.berkeley.edu
> 
> ps: If anybody wants to flame this as a stupid project, I agree fully,
>     but I still have to do it, its graded ;^)
> 

You can design for ramp shutoff, brick-wall current limit or even 
fold-back cutoff....sounds like you want "BRICK-WALL" current limit.

Your lead is correct to pull down the bias to the series regulator base 
drive. In order to get the brick -wall, you need enough voltage gain on 
the current sensor.  Normally a darlington on the current sensing 
resistor will be adequate, but for infinite gain.. use an op amp to sense 
the current releative to a stable voltage reference and use a driver to 
turn off the base bias on the series-pass transistor.  Phase compensation 
may be necessary with this closed loop control system if yopu have more 
than 180 degrees phase shift in your feedabck circuit at unity gain OK??

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54095
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Making up odd resistor values required by filters

idh@nessie.mcc.ac.uk (Ian Hawkins) writes:

> When constructing active filters,  odd values of resistor are often required 
> (i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
> capacitor values and cope with the strange resistances then demanded).
> 
> Is there a PD program out there that will work out how best to make up such
> a resistance, given fixed resistors of the standard 12 values per decade?.(1,
> 1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
> recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
> q and finding prefered values x,y and z.
> 
> 
> 			Cheers
> 				Ian H  
> 

WHen trying to choose a resistor with a tolerance better than 1%, you 
need a trimmer or to screen devices, it can't be made from adding 2 
resitors of 1% value in parallel, since the smaller device will have the 
error of 1% to cope with. 
You have 3 choices;
a) live with the error of 1% tolerance devices for low Q circuits or low 
sensitivity designs
b) buy resistors with better than 1% tolerance (Vishay/Dale)
c) use trimmers or SOT's (Select-On-Test)

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54096
From: baden@inqmind.bison.mb.ca (Baden de Bari)
Subject: Blue LED's

 
        So what's the story here... we're all stuck with the regular
green, red, and off yellow-orange LED's!?  What gives!!??
        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???

                        ... just out of curiosity, of course ...
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

baden@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54097
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Tran tube

I've got a 4PR1000A (EIMAC) unused transmitter tube for sale. Best offer
so far is $125. That's getting close to what I'll sell it for.
Hamfest prices have been about $200 - $250. It works, guaranteed.
Original packaging.
-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
document_id: 54098
From: alany@tekig5.pen.tek.com (Alan Yelvington)
Subject: Re: Lead Acid batteries & Concrete?

The battery goes dead primarily becaust the floor is cold.  The temperature
combined with self-discharge promotes sulfation which ruins the plates of 
the battery.  I strongly suspect that the only reason the battery doesn't
go dead as quickly on a dirt surface is because cement tends to be quite
cooler.


Newsgroup: sci.electronics
document_id: 54099
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Why circuit boards are green?

In article <1993Apr23.105152.20155@news.cs.tut.fi>, kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:
> Not that the question is anything important, but I am still curious:
> Why is that almost all printed circuit boards are green? I have seen
> a few blue ones, but no red, yellow, company logo etc. Is there a
> technical reason or could it be that the marketing "geniuses" have
> not tought about it (yet)?
> --
> Juha
The color of the board shows the composition of it, hence the use of it.

Original and older boards were bakelite composition, and were brown.
Phenolic (spelling) was a tan
Most "non filled" fiberglass boards used in computers are green.
Filled fiberglass is blue.
Teflon is white.

As boards evolved more and more demands were made of them.  First boards were
used mainly in audio circuitry.  Couldn't be used in high voltage or RF because
it would arc and burn.  Most boards today are fiberglass, the type being chosen
by its use and cost.  

Boards in satellite and microwave communication are teflon (and ceramic) as the
fiberglass, and other boards are conductive (they actually work more as a 
capacitive dialectric, but the word conductive simplifies explaination) at the
high frequencies.

Another printed circuit material used mainly in automotive and interconnections
is a thin flexible (mostly mylar) material and is used to connect the front of
the vehicle (etc) to the back instead of wiring harnesses.  Camcorders use this
to intereconnect the boards inside where wires would be a nuisance.

Am working on a generator made by Hewlet Packard right now and the entire board
is gold plated, boy it looks expensive!!!

Hope I got most of my facts right as I am working from memory of material read.

My education was pre-transister!
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
document_id: 54100
From: wwerner@thor.mlb.semi.harris.com (William S. Werner)
Subject: Harris Semiconductor's AnswerFAX Information

     ====================================================
       H    H      A      RRRRR    RRRRR   IIIII  SSSS
       H    H     A A     R    R   R    R    I   S    
       HHHHHH    AAAAA    RRRRR    RRRRR     I    SSSS
       H    H   A     A   R    R   R    R    I        S 
       H    H  A       A  R     R  R     R IIIII  SSSS  
     ====================================================


Harris Semiconductor now has AnswerFAX. AnswerFAX is on-line 24 hours
a day, 7 days a week, so you can instantly receive datasheets and 
application notes by using your touch-tone telephone and FAX machine.
The number to call is (407) 724-3937. (It is not set up to do international
calls at this time.)

The general decision tree for the AnswerFAX is as follows, the numbers are
the available selections:


       Welcome to Harris Semiconductors AnswerFAX
                           |
        ----------------------------------------
        |                                      |
        1                                      2
        |                                      |
 Select 1 if you                        Select 2 for an
 are familiar with                      explanation of
 AnswerFAX.                             AnswerFAX
        |                                      |
        |--------------------------------------|
                           |
                           |                              
                           |
            --------------------------------
            |                              |
            1                              2
            |                              |
     Select 1 to order              Select 2 for a
     a document (the                list of catalogs:
     document list is                  1  New Products
     in the catalogs,                  2  Linear Products
     get them first)                   3  Data Acquisition Products
            |                          4  Digital Signal Processing Products
            |                          5  Discrete Power and Intelligent
            |                             Power Products
            |                          9  Application Notes
            |                              |
            |                              |
  Select appropriate document    Select Appropriate Catalog
            |                              |
            |                              |
  Do you want to order           Do you want to order
  anything else? If yes,         anything else? If yes,
  you will be taken back         you will be taken back 
  to the selection decision.     to the selection decision.
            |                              |
            |                              |
            --------------------------------
                          |
                          |
                          |
                  What is phone number
                    for your FAX?
                          |
                          |
                  What is your name?
               (request the instructions)
                          |
                          |
                         END                        



Bill Werner


===========================================================================
Bill Werner           WWERNER@hsscam.mis.semi.harris.com
Harris Semiconductor  wwerner@thor.mlb.semi.harris.com
Melbourne Florida     "....life is but a candle, and a 
(407)729-5515         dream will give it flame..." - Rush, Caress of Steel
===========================================================================
 


Newsgroup: sci.electronics
document_id: 54101
From: ddexter@solaria.mil.wi.us (David Dexter)
Subject: MK3801 data needed

Hi
Could someone please send me enough info to talk to a MK3801? It's some
kind of multifunction peripheral chip made by Mostek I believe. Any help
would be GREATLY appreciated! Thanks in advance

Dave

-- 
============================================================================
ddexter@solaria.mil.wi.us                     technology thru broken parts
============================================================================

Newsgroup: sci.electronics
document_id: 54102
From: theo@walt.caps.maine.edu (Theo M. Alpert)
Subject: Data Paging Info WANTED


 
 
    Hello, I'm looking for information on Alphanumeric pagers 
and *how* the data is sent from the paging transmitter and how 
I would go about building a device to decode the paging data 
(like my pager does) and feed it though an RS232 port.
    I'm planning on seperating different paging messages and 
different pagers in software to keep amount of hardware I need 
down....  Does anyone know what chips (Motorola?) are good for 
decoding Numeric and Alphanumeric paging data (and then stuffing
it down an RS232 port (basically any baud rate is fine!) ? 
    (I already have a radio reciever with headphone level 
output for the audio signal from the paging tower, but I'd be 
interested in anything you know about pagers, including the 
type of radio recievers they use!)
    Thanks in advance!            
-theo
EMAIL = theo@walt.caps.maine.edu

Newsgroup: sci.electronics
document_id: 54103
From: segross@uci.edu (STEVE GROSS)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.171020.23982@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>In article <rcstage1.128.735548462@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:
>>In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>>[byteocide]

>>>What I believe the companies should do is implement the above plus
>>>a special patch once the user registers that loudly exclaims upon bootup
>>>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>>>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>>>makes it more traceable, because if the patch's registration message is
>>>encrypted, it will be quite hard to change, and therefore provides a
>>>stable trail of who allowed their copy out of their hands, and thus
>>>violated their license agreement.
>>>
>>You take two copies with a different registration id, compare them byte for 
>>byte and you know where they are located. Usually you will be able to 
>>find out what is what after that. 

>Probably, but the point is THE COMPANY make the registration patch, NOT
>YOU.  Sure, you can probably find another registerred user and compare notes,
>but WHY?  It's not hindering you in any way unless you are just hacking.
>[Problem about people who cut TOO MUCH from quoting...]

>>And what keeps me form registering as John Doe from the company Public 
>>Domain, Yellow Brick Road 1, Tinseltown or something???

>Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>via MAIL by mailing in your registration card, THEN the company send you
>the patch which includes the info you put on the registration card.

>--Kasey Chang

I'm glad to see this idea come up because I've had something similar in mind.
What if you had an authorization key that computed from the name and address 
data.  When the user registers, you don't even need to send executable code, 
just compute his/her key and send him/her instructions to enter in the 
appropriate place the following:

Name=Joe Doe
Address=123 Main Street
City=Anytown, CA
key=ldslfoialsdkcdsngsikhsfd

Every user needs a unique key.  The executable can propagate as much as you 
like, the author can respond to the registration by e-mail, post card, 
whatever.  Unauthorized users would have to put up with someone else's name 
showing up (maybe on a main menu screen as well as a startup message).  
Authorized users can make as many copies as they like, upgrade their 
machines, whatever.  The main motivation here is guilt and irritation at 
seeing someone other than yourself as the "registered owner".

Newsgroup: sci.electronics
document_id: 54104
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead Acid batteries & Concrete?

In article <9649@tekig7.PEN.TEK.COM>, alany@tekig5.pen.tek.com (Alan Yelvington) writes:
|> The battery goes dead primarily becaust the floor is cold.  The temperature
|> combined with self-discharge promotes sulfation which ruins the plates of 
|> the battery.  I strongly suspect that the only reason the battery doesn't
|> go dead as quickly on a dirt surface is because cement tends to be quite
|> cooler.

Please explain how cement is able to maintain a lower average temperature
than dirt.  Sheesh.......



Newsgroup: sci.electronics
document_id: 54105
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Pin-out for 27C64??

In article <skelly.18aw@amiganet.chi.il.us>, skelly@amiganet.chi.il.us (Sean Kelly) writes:
|>  
|>  
|>      Does anyone know the pin-outs for the 27C512 EPROM??  I have bought
|> several of them, none of which has come with the pin-outs!  Any info would be
|> appreciated....

A good source of information for data of this type is the library.
In particular the library at a local college or technical school offering
courses in electronics would have data books of this nature.


Newsgroup: sci.electronics
document_id: 54106
From: little@nuts2u.enet.dec.com (My name is...)
Subject: FOR SALE: OMTI 3527 : ST-506 RLL to SCSI adapters


I have 2 OMTI 3527 SCSI adapters for sale.  These make an ST-506 RLL drive
look like a SCSI disk drive.  Each adapter will support two RLL drives.  I
have used this model OMTI adapter with my Amiga A500 and a C-Ltd SCSI host
adapter without problems. I'm selling these because I got them about the
same time I decided to sell instead of expand my Amiga so I have never even
used them.  I can't guarantee they will work with every SCSI host adapter.

They are essentially new in box. I paid $150/ea, make me an offer.

Regards,
Todd
(708) 202-1030
little@pecan.enet.dec.com

Newsgroup: sci.electronics
document_id: 54107
From: witr@rwwa.COM (Robert Withrow)
Subject: Re: Cable TVI interference

In article <1qf44aINNll@rave.larc.nasa.gov>, watson@nimbus.larc.nasa.gov (Catherine Watson) writes:

| I gave up after a year of
| letters and phone calls.  I got the impression the FCC was powerless and it 
| was up to the cable company to correct the situation.

Isn't there some *formal* action a citizen can take that *requires* the
FCC to, at least, generate some paperwork?

-- 
 Robert Withrow, Tel: +1 617 598 4480, Fax: +1 617 598 4430, Net: witr@rwwa.COM
 R.W. Withrow Associates, 21 Railroad Ave, Swampscott MA 01907-1821 USA

Newsgroup: sci.electronics
document_id: 54108
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr23.190152.13088@mprgate.mpr.ca> vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>In article <9649@tekig7.PEN.TEK.COM>, alany@tekig5.pen.tek.com (Alan Yelvington) writes:
>|> The battery goes dead primarily becaust the floor is cold.  The temperature
>|> combined with self-discharge promotes sulfation which ruins the plates of 
>|> the battery.  I strongly suspect that the only reason the battery doesn't
>|> go dead as quickly on a dirt surface is because cement tends to be quite
>|> cooler.
>
>Please explain how cement is able to maintain a lower average temperature
>than dirt.  Sheesh.......

It's not the temperature, it's the karma.  You see, dirt has good karma,
since it's all organic and full of living things, but cement is all squared
off and artificial looking, and has lost its karma in the process.  Being
a karma sink, it sucks all of the good karma out of the battery which is no
longer able to keep a charge.  Because wood is also good and organic, putting
a board between the battery and the cement will fix the problems.

The Buddha-nature is in the acid, but it is also in the lead plate.  The
novice asked the master whether the spongy lead had more of the karma or
whether the solid lead had it.  The master handed the novice a 250V B battery,
terminals downward, and thus the novice was enlightened.
--scott

Newsgroup: sci.electronics
document_id: 54109
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Question on addressing...

In article <skelly.18c2@amiganet.chi.il.us>, skelly@amiganet.chi.il.us (Sean Kelly) writes:
|>  
|>  
|>      I have a question about accessing certain addresses on a chip,
|> particulary a 27C512 EPROM.  Although I don't know that much about it, as I
|> understand it, there's a pin on the chip that, when voltage is applied, kicks
|> up the address.  The question is how do you determine how many bytes the
|> address is incremented by??  For example, if I have code I want to be
|> accessed at $2000 and also at say $4000 how do I move the address pointer to
|> those positions??  Thanks for any info...
|> 
|> %^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
|> %   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
|> %   Always looking for classic video games for the following systems:   %
|> %                                                                       %
|> %  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
|> %^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Judging by your .sig you are trying to make some kind of game cartridge.
Information of how to build an EEPROM cartidge for the vectrex is available
via anonymous ftp at 'csus.edu'.

Since you've chosen the 27C512 you are probably trying to make a 'multicart'.
To do this simply:
1. Load the game images into the EEPROM at $2000, $4000, etc. (Your EEPROM
burner software may allow this or you will have to assemble the images into
one file yourself with suitable gaps.)
2. Wire up the cartridge with the lower address bits going to the game
console, and the high bits going to switches to choose between games.

To directly answer your question above, the pin that 'kicks up the address'
is simply another address line.

For a concrete example, with the 27C512 and 8K games images, you would
wire A0-A12 to the cartridge, and A13-A15 to 3 switches.  The 3 switches
would allow you to pick from the 8 games on the EEPROM.


Newsgroup: sci.electronics
document_id: 54110
From: stevenm@kralizec.zeta.org.au (Steven Murray)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


>>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>>	Hello again,
>>> I asked this a year ago, but i am still looking.
>>> I am getting sick of having to use a HC373 

If you are just getting sick of the real estate used by the HCT373, you could
always use the approach I have seen one designer take - he stuck the chip in
the middle of the EPROM socket, under the EPROM.  Naturally, you have to use
an IC socket with the right dimensions, but layout is really easy.

-Steven Murray

Newsgroup: sci.electronics
document_id: 54111
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Question on addressing... (correction)

A little correction on my previous post about an hour ago.
Please replace the term 'EEPROM' with the term 'EPROM' wherever it appears.
(Don't not why I added that extra 'E' every time.)


Newsgroup: sci.electronics
document_id: 54112
From: Carr-C10973@email.comm.mot.com (Eric Carr)
Subject: Re: help with phone wire: which ones are "tip" & "ring"?

In article <1993Apr22.103922.23177@husc3.harvard.edu>,
mlevin@husc8.harvard.edu (Michael Levin) wrote:
> 
> 
> I just bought a little gizmo that is supposed to be installed "in
> series with the tip or ring lines" of the phone wire. Which ones are
> those? Suppose I am holding a regular phone wire, such that the little
> plastic tooth (on the little plastic square thing with the naked lead
> ends that you plug into the phone) is facing down, and away from me.
> Which of the 4 wires that I see is the "tip" and which is the "ring"?
> Please reply to mlevin@husc8.harvard.edu.
> 
> Mike Levin

Assuming you are refering to standard POTS or ground start lines:

If you are looking at loop start lines under idle conditions, the RING
conductor is the one with approximately -48 to -52 vDC with respect to
ground while the TIP conductor is at or very near ground potential (be sure
to reference the telco ground when taking your measurements).  

If you are dealing with ground start lines under idle conditions, the RING
conductor will be the one with approximately -48 to -52 vDC while the TIP
conductor would look like it's floating (you may see some potential from
line capacitance it will bleed off over time).  Remember to use the telco
ground as your reference when making measurements. 



                                   _________
                            ______/        /_______
                           /     '67 Caprice      /
                          /_____ Sport Coupe_____/
                                /_________/


                              
                                          

Newsgroup: sci.electronics
document_id: 54113
From: seema@madvlsi.columbia.edu (Seema Varma)
Subject: Luser!

Hi,
	I am looking for a very high speed 
D/A converter (at least 8bits and 150MHz) for
a research application. A paper in  the January
issue of IEEE Solid-State Circuits mentions a 
GaAs, 1GHz, 8bit DAC - anyone know where I can find
such a thing? Even a somewhat slower Si DAC would
do.
	Needless to say, I have looked in all the
conventional places (Vitesse, Motorola, National,
etc. etc.). Any pointers would be appreciated.

--- Seema Varma

Newsgroup: sci.electronics
document_id: 54114
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu>
sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes: 

backupable, if restored to the same machine >>(depends>> on the
programmer...  don't use a disk drive characteristic!) If the user >> did
an upgrade to the machine, he/she should reinstall all programs any way.
>> No document look-up, no disk wear-and-tear! > 

> This is not a good idea.. I upgraded my motherboard last fall.  I >would
have been quite pissed at any software that would have forced me to
>reinstall simply because I changed motherboards. >

Opinion is understandable.  :-)  I assume you have a tape drive?  Not all
of us have about 200 floppies around for backup, you know.  

> Any info in the BIOS is too volatile to use as a checksum.  Are you
>going to require that a user re-install all their software if they add
4Mb >of RAM to their computer?  I did that a couple of weeks ago.  It's in
the >BIOS, and if software had told me "this isn't the machine you
installed me >on" I would never have used that software again.  Really bad
idea. 

RAM is something you add all the time, so no.  It's more like BIOS
manufacturer and/or processor type (386/486/etc).  Data cannot be used,
esp with these new Flash ROM BIOS machines with updates on a diskette.

On the other hand, to make this LESS intrusive it could be disguised as
"Please Insert Original Disk #XX as I need file YYYYYY for update".  :-) 
It would be perfectly reasonable...  Sort of.

> >> I did not say that the originals would allow only one install.  The
user's >> conscience should do that. 

> > This is silly.  It's much easier to loan disks to a friend and let
>them do an install than to backup your copy already on disk, and then
give >them that.  Your scheme isn't going to stop anyone. 

Of course it is easier.  Are you saying then the originals SHOULD allow
only one install?  What is your point?

> >> You know how many bytes you need to change in X-wing to disable >>
the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)

> > Do you know any assembly language at all?  All anyone needs to do if
>find the part of the code that does the quiz, and insert a JMP
instruction >to just completely skip it.  Not that difficult, really!  And
there is very >little that commpanies can do to stop this type of thing. 
Using PKLITE or >some similar utility would help, but only if the
resulting compressed .EXE >were tagged as uncompressable. 

I know x86 and 680x0 assembly quite well, thank you.  I know exactly which
two bytes need to be changed, I have the code to do them too.  I just said
"Don't ask me which ones."  I didn't say I don't know what that means.

Such hacking can be EASILY discouraged by adding anti-patching code which
does a self-check upon execution and refuse to load if CRC does not match
value stored (encrypted, of course) in the program.  It could be claimed
as a part of anti-virus code, and it would not be far from the truth. 

> >> What I believe the companies should do is implement the above plus >>
a special patch once the user registers that loudly exclaims upon bootup
>> "REGISTERED TO XXXXX -- address, city, state zip" and disables the
above. 

> > This is by far the best idea you presented in your post.  Making it
>plainly obvious who registered is going to stop casual pirates. But, the
>determined ones are just going to answer "Joe Blow" to the question of
>"what's your name" so this won't stop them in the long run. 

Did ANYONE read what I wrote?  That is NOT what I wrote! (or meant!)  

What I said was the program should have certain restriction (such as the
restrict-to-one-machine) UNTIL the program is registered with the
manufacturer.  The manufacturer will then supply the
then-proven-legitimate-user with a patch that will disable the restriction
and PROUDLY PROCLAIM the legal copy with the "Registered to XXX" screen.

> > Pirates are always going to win this fight.  They simply have more
>time to work on the software and figure out the protection scheme. 

Of course they will, but that was NOT my point.  The purpose of copy
protection is to discourage casual pirates ("Oh, can I have a copy of
that?"/"Sure, here.") and the less sophisticated pirates ("Let's look for
all those calls to INT13H...") .  Any one determined enough to break copy
protection can and will succeed.  They can always backtrace the entire
load-sequence of the program.  The point of copy protection is to make
such attempts take as long as possible while not intruding upon the uses
(or to minimize such intrusion) of legitimate use.  Pirates who see copy
protection as a challenge love breaking them, and no amount of copy
protection will stop them, but the rest of us WILL be stopped.  How many
of these hardcore pirates are there compared to rest of us?  Not that many.

--Kasey Chang

Newsgroup: sci.electronics
document_id: 54115
From: ebraeden@magnus.acs.ohio-state.edu (Eric W Braeden)
Subject: What exactly is an IBM 486SLC processor?

Could someone please tell me if the 486SLC and 486SLC2 processors
IBM is putting in their Thinkpad 700's and other PC's is a REAL
486 with a math coprocessor or if it is really some Kludge that
should not be called a 486 at all?

Thanks,
Eric
-- 
Eric W. Braeden                    | "Der Verstand war zwar praechtig
Ohio State University              | doch das Nuetzte am Ende nicht viel"
ebraeden@magnus.acs.ohio-state.edu | Peter Schilling   120 Grad    1983

Newsgroup: sci.electronics
document_id: 54116
From: neal@cmptrc.lonestar.org (Neal Howard)
Subject: Re: Lead Acid batteries & Concrete?

In article <C5x3E6.3nx@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>>
>>  Why does a lead acid battery discharge and become dead (totally unuseable)
>>when stored on a concrete floor?  
>>  I decided to bring the battery in from the lawn mower and the motorcycle
>>from the unheated garage this year, *to preserve them* and I just
>>went to use them and noticed that not only do they not work, but 
>>they act like the two terminals are shorted.  I asked a friend
>>and he said that you should never do that, 'cause it ruins them,
>>but he couldn't tell me why.
>
>This topic was beaten to death a year or so ago.
>
>The concrete is not the problem. 
>
>Lead-acid batteries often fail from disuse (not being charged for a long
>time), but there's no way the concrete floor could be the cause of the
>problem.

The concrete floor accelerates the problem because it is a heat sink and a
colder lead-acid battery self-discharges at a slightly faster rate. That's
why the old wives' tale of sitting it on a piece of wood on the floor works
to help keep from killing the battery as fast ---- it insulates the battery
thermally. It you'll set the battery down on a piece of styrofoam, it will
self-discharge even slower. The best thing would be to attach a small load
such as a small transistor radio with the volume turned down low and leave it
on constantly, but also trickle-charge it every couple days too to "shallow-
cycle" the charge in the battery. Such mild "exercising" of a lead-acid
battery is the next best thing to completely removing the electrolyte for
storage. If you do remove the electrolyte, may sure you keep separate storage
containers for each cell's electrolyte and put it back into the same cells
when you refill the battery. This isn't so critical for a brand-new battery
in a fully charged state, but will maximize the restored output of an older
battery which may not be fully charged when you remove the electrolyte for   
storage.
-- 
=============================================================================
Neal Howard   '91 XLH-1200      DoD #686      CompuTrac, Inc (Richardson, TX)
	      doh #0000001200   |355o33|      neal@cmptrc.lonestar.org
	      Std disclaimer: My opinions are mine, not CompuTrac's.
         "Let us learn to dream, gentlemen, and then perhaps
          we shall learn the truth." -- August Kekule' (1890)
=============================================================================

Newsgroup: sci.electronics
document_id: 54117
From: wiegand@rtsg.mot.com (Robert Wiegand)
Subject: Re: Lead Acid batteries & Concrete?

camter28@astro.ocis.temple.edu (Carter Ames) writes:


>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)

>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.

I don't see any way that the concrete floor could do anything to the
battery.

However, you would have been better off leaving them outside. Keeping
them cold would have been better for them than bringing them inside.
A warm battery will self-discharge faster than a cold one.

When you are storing a battery it's a good idea to charge it once a month.
Letting a battery go completely dead is bad for it (I suspect this is
what caused your problems).

-- 
------------------------------------------------------------------------------
Robert Wiegand - Motorola Inc.
wiegand@rtsg.mot.com
Disclamer: I didn't do it - I was somewhere else at the time.

Newsgroup: sci.electronics
document_id: 54118
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: NEED help finding parts!

OK I posted this B4 but:

___ Blue Wave/QWK v2.12
                                                                              

Newsgroup: sci.electronics
document_id: 54119
From: klp@doe.carleton.ca (Ka Lun Pang)
Subject: Self-destructing copy protection on VHS tape?


Hi folks,

I borrowed a VHS tape from a friend and it has a warning in the begining saying
that attempts to copy the tape will result in destroying the copy and the
original. I found this unbelievable as playing and recording are two different
processes. However, I've never seen this tape being sold anywhere so I don't 
want to take the chance even it's small.

Anyone has experience in this kind of self-destructing video tapes?

Thanks in advance.

--
Ka Lun  Pang (a.k.a. Andy) - Lost between frequency and time on the unit circle
                      email: klp@doe.carleton.ca 
                               DoD# 0687

Newsgroup: sci.electronics
document_id: 54120
From: Mark Yeck <my10+@andrew.cmu.edu>
Subject: D,G,&H type Amplifiers

Hey, can someone clue me in on these and other weird types of amplifiers?  Just
a brief intro to the concepts behind these would be cool.  I have the clues 
on type A, B, and AB already and stuff, but these other ones are mentioned 
occasionally and I dont know what they do.  I think type D is like a PWM scheme
or something.  Thanx in advanced.


-mark
(my10@andrew.cmu.edu)

Newsgroup: sci.electronics
document_id: 54121
From: tl@etek.chalmers.se (Torbj|rn Lindgren)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu> sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes:
>	Do you know any assembly language at all?  All anyone needs to do if
>find the part of the code that does the quiz, and insert a JMP instruction
>to just completely skip it.  Not that difficult, really!  And there is very
>little that commpanies can do to stop this type of thing.  Using PKLITE or
>some similar utility would help, but only if the resulting compressed .EXE
>were tagged as uncompressable.

And even that doesn't help, there are at least two programs available
that fixes this (UNP and DISLITE, both available from Simtel-20). And
even without them it isn't THAT hard to fix.

Newsgroup: sci.electronics
document_id: 54122
From: jott@scarecrow.cse.nd.edu (John Ott)
Subject: RE: Food Deydrators


Article: 41686 of sci.electronics
Newsgroups: sci.electronics
Path: news.nd.edu!spool.mu.edu!howland.reston.ans.net!bogus.sura.net!news-feed-1.peachnet.edu!gatech!asuvax!ennews!mcdphx!schuch
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Food Dehydrators
Message-ID: <1993Apr19.154356.17880@phx.mcd.mot.com>
Sender: news@phx.mcd.mot.com
Nntp-Posting-Host: bopper2.phx.mcd.mot.com
Organization: Motorola Computer Group, Tempe, Az.
Distribution: usa
Date: Mon, 19 Apr 93 10:43:56 EST
Lines: 9

>  Does anybody out there have one of those food dehydrators I've been seeing
>all over late-night TV recently? I was wondering if they use forced air, heat,
>or both. If there's heat involved, anybody know what temperature they run at?
>My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
>and a heater. Seems to me you should be able to throw a dehydrator together
>for just a few bucks. Heck, the technology is only what? 1,000 years old?
>
>John

Try Mother Earth News, Feb/March 1993, pg 54, "Build a Food Dryer"

John

Newsgroup: sci.electronics
document_id: 54123
From: jmiller@terra.colostate.edu (Jeff Miller)
Subject: Re: How to the disks copy protected.

: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
: via MAIL by mailing in your registration card, THEN the company send you
: the patch which includes the info you put on the registration card.

The problem with this scheme, is that when I buy a game, I want to play it
*THAT* day...mailing a card to and from California would probably take a week
or more.
--
 _____________________________________________________________________________
|                                                                             |
|  jmiller@terra.colostate.edu  |   Jeff Miller  |  TERRA Lab Systems Admin.  |
|_____________________________________________________________________________|

Newsgroup: sci.electronics
document_id: 54125
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead Acid batteries & Concrete?

neal@cmptrc.lonestar.org (Neal Howard) writes:

>The concrete floor accelerates the problem because it is a heat sink and a
>colder lead-acid battery self-discharges at a slightly faster rate. That's
>why the old wives' tale of sitting it on a piece of wood on the floor works
>to help keep from killing the battery as fast ---- it insulates the battery
>thermally. It you'll set the battery down on a piece of styrofoam, it will
>self-discharge even slower.

There are a number of inaccuracies here:
1) In fact, a colder battery will self-discharge more slowly.  This is why
   batteries should be stored in a COOL, dry place.
2) An battery placed on concrete does not become colder than one placed
   on wood.  The battery, the wood, and the concrete will all be at the
   same general temperature (ignoring temperature fluctuations) and thus
   none will effect the other.

>The best thing would be to attach a small load
>such as a small transistor radio with the volume turned down low and leave it
>on constantly, but also trickle-charge it every couple days too to "shallow-
>cycle" the charge in the battery. Such mild "exercising" of a lead-acid
>battery is the next best thing to completely removing the electrolyte for
>storage.

There is no need to 'exercise' the battery.  Just keep it charged.  (A trickle
charger will do the job.)

[stuff deleted]

Newsgroup: sci.electronics
document_id: 54126
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: !!!] HELP!  NEED 3479P!!! [!!!


                Would anyone have a few extra 3479P's lying around that I 
could buy off of them.. Problem is that around here I can only perchase 
them in $30 quantities, and I don't need this, and can't take this 
financially right now.... 
 
                        If anyone can accomodate me with this PLEASE 
reply to BOTH for the following mailing addresses...
 
                        Thanks!!!
 
_______________________________________________    
             |                                 |
   _______   |    Baden de Bari                |
  /       \  |     baden@sys6626.bison.mb.ca   |
 (| o   o |) |     baden@inqmind.bison.mb.ca   |
  |   ^   |  | >> True life can only           |
  \  -=-  /  | >> be experianced by            |
   \_____/   | >> those who do not fear death. |
-----------------------------------------------


Newsgroup: sci.electronics
document_id: 54127
From: weaver@kuttner.sfc.sony.com (Eric Weaver)
Subject: Re: ATARI 2600 Processors


I'm a 2600 hacker from The Old Days.  Let's see how much trouble I can
get into by telling you what you want to know...   ;-}
-- 
Eric Weaver  Sony AVTC  677 River Oaks Pkwy, MS 35  SJ CA 95134  408 944-4904
& Chief Engineer, KFJC 89.7 Foothill College, Los Altos Hills CA 94022

Newsgroup: sci.electronics
document_id: 54128
From: erini@enterprise.ifp.uiuc.edu (Erini Doss)
Subject: CELLULAR ANTENNAS

 i need to get some info a.s.a.p. about the cellular
antenna market out there right now:  who are the main
companies making them, how much do they cost, what are
the specs (such as gain , directivity, etc.), and who
is the contact person because a group of us here are
at the Univ.of IL are researching into this technology


I will personally mail you a copy of our entire busineess
plan and paper if you can be of any help..

e-mail me at erini@enterprise.ifp.uiuc.edu



Newsgroup: sci.electronics
document_id: 54129
From: erini@enterprise.ifp.uiuc.edu (Erini Doss)
Subject: CELLULAR ANTENNAS

 i need to know about the market for cellular antenna
technology today... who are the main companies in the
market.. how much are they selling them for? who are the
contact people?  what are the specs?

I will mail oyou our reserach so far if youcan help us!!


erini@ifp.uiuc.edu



Newsgroup: sci.electronics
document_id: 54130
From: triumvir@cco.caltech.edu (Martin W. Lin)
Subject: Audio/Electronic Parts, esp in Los Angeles

I'm working on an audio mixer project, but I'm having trouble finding
parts.  I want to use op-amps for the gain control stages.  The ones
I have found that are good for audio are LM739 and LM833, but I cannot
find either of these in the electronic parts places I've looked.

Are there any good substitute op-amps and/or are there any parts
suppliers in the LA area that carry this kind of thing (10KOhm dual
audio taper slider pots would be nice, too).

Any info would be appreciated.  Thanks in advance.

Martin Lin
triumvir@cco.caltech.edu


Newsgroup: sci.electronics
document_id: 54131
From: maynard@selway.umt.edu (Robert L Maynard)
Subject: Re: How to the disks copy protected.

> noeler@xanth.CS.ORST.EDU (Eric Richard Noel) writes:
> >
[Discussion on Piracy Deleted]
> 
> Off deeper end-> Why does everyone think they need to be able to make a 
> backup copy? Almost all new software must be installed to the hard disk,
> so you are left with the originals as your backups. I think its a waste
> of time, space, and money, as well as it makes it to tempting to "lend"
> out the backups. 
> 
My own practice with new software :

make a copy of the original floppies to a second set of floppies.

install to hard drive from second set of floppies.

put originals in a box in room number one.

put copies in box in room number two.

1) Accidents DO happen to original floppies.
2) Accidents CAN happen to the installation floppy.
3) Sometimes software goes out on floppies that are JUST marginally good.  Or
   gets too close to a magnet in shipping or storage.

I've had experience with SOMETHING like the last.  I purchased a compiler from
a reputable vendor.  THe debugger in the package just would NOT install to the
hard drive. NO WAY.  Repeated floppy-to-floppy copies FINALLY got a clean read
of the disk.  I DON'T recall if I used "diskcopy", "copy/b", or "xcopy".

I made a second copy of the marginal floppy and installed from that.  No problenms ( except with my typing :-)  ) since.

I regard backup floppies as CHEAP insurance.

Just my side of the question...

Bob

Newsgroup: sci.electronics
document_id: 54132
From: jeh@cmkrnl.com
Subject: Re: Los Angeles Freeway traffic reports

In article <C5sLMB.9w6@cup.hp.com>, dclaar@cup.hp.com (Doug Claar) writes:
> While driving through the middle of nowhere, I picked up KNBR, AM 1070,
> a clear-channel station based in Los Angeles. 

KNX AM, 1070 in LA, will be unhappy to hear about this, I'm sure. :-) 

(isn't KNBR in the bay area?)

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
document_id: 54133
From: gladman@ecf.toronto.edu (GLADMAN AVIV)
Subject: Re: Blue LED's

In article <Zw6F3B1w165w@inqmind.bison.mb.ca> baden@inqmind.bison.mb.ca (Baden de Bari) writes:
> 
>        So what's the story here... we're all stuck with the regular
>green, red, and off yellow-orange LED's!?  What gives!!??
>        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
>

In order to emit blue light, a semiconductor must have a band gap energy
within the region of 2.6 to 2.8 electron Volts. According to my physical
electronics prof, you can't get an LED with that band gap. That's why you
don't find blue LEDs or, for that matter, some other colour of LEDs. That
is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
but they were just your typical visible light LED in a blue plastic covering.
They didn't emit very much light...

Source: Solid State Electronic Devices (Ben G. Streetman, 3d ed., Prentice
Hall)
-- 
-----------------------------------------------------------------------------
"Right planet, wrong universe" - Douglas Adams
"If we took the bones out, it wouldn't be crunchy" - Mr. Whizzo
-----------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54134
From: stone-andy@cs.yale.edu (Andy Stone)
Subject: Re: How to the disks copy protected.


	I wrote a commercial program called GAME-MAKER (can you guess what
it does).  What we do is have a document protect (answer Question on page x, 
line y), which is a real pain.  We also allow the user to register by sending
in a card, and computing a # based on their name.  The system works in that
we've gotten lots of registration cards.
	I hear that the program has been cracked though.  Someone two people 
actually called up my support--one with a question, the other wanting to
buy our graphics libraries (right!).  Anyway if anyone wants to help me
catch a cracker and has the cracked version, mail me.  I won't accuse
you (unless you're the cracker of course).

--
                                             Andy Stone      
-					     stonea@suned.cs.yale.edu
-- 
                                             Andy Stone      
-					     stonea@suned.cs.yale.edu

Newsgroup: sci.electronics
document_id: 54135
From: davidj@rahul.net (David Josephson)
Subject: Re: Blue LED's

In <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:

>In article <Zw6F3B1w165w@inqmind.bison.mb.ca> baden@inqmind.bison.mb.ca (Baden de Bari) writes:
>> 
>>        So what's the story here... we're all stuck with the regular
>>green, red, and off yellow-orange LED's!?  What gives!!??
>>        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
>>

>In order to emit blue light, a semiconductor must have a band gap energy
>within the region of 2.6 to 2.8 electron Volts. According to my physical
>electronics prof, you can't get an LED with that band gap. That's why you

He's mistaken. They exist, the semiconductor is silicon carbide, and they
are inefficient and expensive. The bandgap is around 2.7 ev.

>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...

The ones I have are clear plastic. Pray tell, what would make a "typical"
LED emit blue light?


-- 
David Josephson <davidj@rahul.net>

Newsgroup: sci.electronics
document_id: 54136
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: How to drive an array of LEDs?

I have a project in mind that requires an array of LEDs that can be addressed
individually by a microprocessor (say, 16x16 or so).  Is there an LSI that
is designed to drive an LED array (including RAM to hold the array state),
or failing that, some way of multiplexing the display so I don't have to
latch a bit for each LED using a discrete latch?  (I want to avoid having
a huge board covered with 373s if possible!)  Thanks in advance...

Phil Torre (ptorre@u.washington.edu)

Newsgroup: sci.electronics
document_id: 54137
From: rpo@trsvax.tandy.com
Subject: Re: IR detector 'cards'???


Radio Shack stores sell them here in the States. Not sure if
InterTan is carrying these for Australia or not...

Cost is $6 USD. You charge them under a fluorescent, then
they glow when exposed to IR.

Paul Opitz
Radio Shack Publications


Newsgroup: sci.electronics
document_id: 54138
From: alung@megatest.com (Aaron Lung)
Subject: Looking for Toshiba TA6267 specs

I'm looking for some specs for a Toshiba TA6267-BP.  It appears
to be a power amp housed in a 7-pin inline package and is used
in my Mitsubishi VCR, circa 1985, as a DC motor controller for
the tape drive.

Checking in the oldest IC Master I have (1990), I don't see it
listed, and it appears to have been discontinued.  If anyone
has anything on this part, I'd be *greatly* indebted!

thanks in advance,

aaron

Newsgroup: sci.electronics
document_id: 54139
Subject: Re: Power, signal surges in home...
From: emd@ham.almanac.bc.ca

clewis@ferret.ocunix.on.ca (Chris Lewis) writes:

> In article <1r1jmoINN8mb@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Sc
> >In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Doug
> >>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) wri
> 
> >>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
> >>   that a ham would be running that kind of power from a car.  Ham rigs
> 
> >>Not possible either.  You'd need about a 300 amp alternator for
> >>just the amplifier.  I can just see it.  You need to slow
> >>down on a downgrade,  so you hit the push to talk button.
> 
> >Now, that indeed is possible.  A good friend of mine is running about 1 KW
> >PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
> >the rig an "electronic brake" since the engine noticeably slows when the
> >key is down.
> 
> It has been a while since I knew the electronics of ham radio, but I seem
> to remember that PeP is actually 4x the "real" power.  Which makes 1KW PeP
> actually around 250W.  Or was it 2x?  I disremember.
> 
> "Effective transmitted power" is also "odd", in that it takes into account
> antenna height and geometry.  Which is why a TV station with a 50KW Klystron
> might advertise a megawatt (if their antenna is on the top of the
> CN tower ;-).
> 
> This is like Sears HP ;-)
> 
> Though, 1500 real watts still isn't impossible.  About 125-150A with
> a 12V alternator, less if the alternator produces higher voltages.
> 
> It's only three horsepower (taking into account inefficiencies).  You'll
> feel it when you hit the key.  But not too much.
> -- 
> Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
> Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
> Ferret list: ferret-request@ferret.ocunix.on.ca


It sorta depends on what you drive. I remember running a two channel 
Motorola with a vibrator power supply and about 40 tubes in a 1958 
Volkwagen. The poor little 6 V generator had a heck of a time, and if you 
keyed the mic at night, you needed to be stationary, because your lights 
got AWFUL DIM. Isn't progress wonderful?


emd@ham.almanac.bc.ca (Robert Smits Ladysmith BC)

Newsgroup: sci.electronics
document_id: 54140
From: adrian@tasman.cc.utas.edu.au (Adrian Lewis)
Subject: cleaning electronic equipment?

Hi,
	Just a quick question.  What standard lab solvents can be used to
clean electronic equipment and components safely (ie not corrode, dissolve,
short-out, etc the equipment)?
	water?	:-)
	methanol?
	CCl4?
	etc?
I am not an electronics type (surprise, surprise), and I want to avoid using
freons.

Thanks,		Adrian


Newsgroup: sci.electronics
document_id: 54141
From: ejajko@hertz.elee.calpoly.edu (Edward Jajko)
Subject: Re: How to the disks copy protected.

In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU (Eric Richard Noel) writes:
>I strongly disagree. I think most pirating is done by amateurs, who won't
>copy the program if "diskcopy" can't do it.

I hate to disagree, but I will. :)
(note: I don't pirate software, nor do I trade it. I simply have met and
talked extensively with those who have. that's it. the FBI can tap someone
else's phone :)
Most pirating is done by people who don't use the programs they pirate.
A cracked program tends to get passed on, resplendant in the various graphics
and animations that advertise whoever performed the modification(s).

I admit that a large portion of the business world is involved in 'giving'
copies of programs to one's fellow workers, maybe taking it home for use
on one's own PC, but such trading tends to be interdepartmental or at most
spread throughout the business as a whole- how many times have you had
someone walking from business to business letting people copy disks?

It's mostly a matter of convenience: a person sees a program they want to
use and they feel justified in making a copy since "someone's already paid
for it", etc., etc. (A note: this is starting to change a bit. not much
though.)

>If you're talking a 20% max goal of pirated copies, I bet that anything that
>will beat diskcopy, and can't be easily copied from a hard drive, will
>suffice.

what about commercially available copy programs? CopyII?
how about programs like teledisk, that can do things diskcopy can't?
and before anyone disputes this because they feel that those who would copy
wouldn't know about this:
  after working with people around computers, one comes to realize that
the 'average' user doesn't know much. Any computer enthusiast is at least
200x better at pre-guessing commands and how to use them (can *you* sit down
and use something without reading the manual?) and it is these people who
are doing the '20% pirating', not Joe Windows User who can't remember a few
arguments to the dir command.

>I hate hard copy manuals, and would rather have all docs online - *not*
>because I want to copy the program, but because its usually faster and
>and convenient than sifting through an old book I can't find.

really? I find it evens out- the online stuff can be read through faster,
but you're stuck reading it in linear flow: start to finish, unless you
jump ahead with a search or such. A book, though, you can flip through
faster than you can read text on a screen and they usually have a nifty
index too!

But I partially agree: I often wish I could grep something that was written
down.

>Off deeper end-> Why does everyone think they need to be able to make a 
>backup copy? Almost all new software must be installed to the hard disk,
>so you are left with the originals as your backups. I think its a waste
>of time, space, and money, as well as it makes it to tempting to "lend"
>out the backups. 

what if they need to re-install? The idea of a backup still holds- if
the original disk goes bad, they're out of luck for about 1-2 weeks, which
is the usual turn around time for a company to send a new set of disks-
if they'll do it without a charge.

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
::::::::::::::::::::::::::::::: Edward W. Jajko :::::::::::::::::::::::::::::::
::::::::::::::: The Nekomancer :: ejajko@hertz.elee.calpoly.edu :::::::::::::::
::::::::::::::::"Mein Fuhrer! I can walk!!" -Doctor Strangelove::::::::::::::::
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Newsgroup: sci.electronics
document_id: 54142
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <CSTROCKB.93Apr23002520@csws8.cs.sunysb.edu>, cstrockb@cs.sunysb.edu (Caleb Strockbine) writes...

>Could make for some interesting choreography... light and sound could be 
>controlled directly by the position of a dancer on stage, or by the number
>of dancers on stage. Neat.
> 
>You could even build a spotlight that follows the dancer around on stage!
> 
>Can you tell us more about what you're doing? Sounds like a very cool program.

Tis' only a gleam in my eye at this point.  I have yet to chose a tracking 
method.  The initial requirement was to design a system to locate a dancer
in one of eight zones across the stage.  I did some experiments with 
pyroelectric detectors and found them difficult to align to get a definite
zone transition.  And dancers stand still alot, so their IR signature goes
away.  The good thing about pryoelectrics is that their signal is proportional 
to the size of the warm body (or body part), and the velocity of said body.
This could be useful for detecting the intensity of a dance gesture.

Dancers also really hate to wear little boxes and batteries strapped on their 
bodies, but they really need to be emitting some kind of signal to be tracked.

The current toy I have been working with is a program called Mandala for the
Amiga, used with a LIVE! video digitizer.  This works with a video camera 
trained on the stage.  You can set thresholds for a zone within the field of
view, and an object brighter than the threshold will trigger an event. Events
can be MIDI objects or sequences, Amiga sounds or graphic objects.  It's been
fun to play with, but the documentaion is arcane, and the digitizer is noisy.
Still, it's very appealing, the dancers don't have to wear any appliances,
you can have ots of zone,s, it speaks MIDI, which can be used to control lights,
and I don't have to build any electronics.  It's all done with lighting and
video brightness and contrast adjustments.  I have yet to do anything
particularly useful or artistic, but I have hopes...


Newsgroup: sci.electronics
document_id: 54143
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Need help with video detection circuit

verity@jack.sns.com (Steve Verity) writes:
> I am trying to build a circuit that detects the presence of video (Vs.
> a blank screen) by monitoring the R,G, and B outputs of a graphics
> card.  It should be able to detect the presence of a single pixel at
> 65 MHz, which would mean detecting a 15 NS pulse.  It should also be
> able to tell the difference between a blank screen (about 300 mv)
> and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
> cheap.  ............... In 
> fact the difference between completely black and completely white is
> only 650 mv.  I am wondering if I am going to have to amplify the
> video signals to make this work.  

Try a differential amplifier. Put back-to-back diodes between the collectors
restrict the voltage swing. Have 10 mA flow, with 500 ohm collector Rs, and
keep the stray C below 10 pF. Try 2N5179s. Run collector to your logic.
Allen Sullivan     




Newsgroup: sci.electronics
document_id: 54144
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>
>In order to emit blue light, a semiconductor must have a band gap energy
>within the region of 2.6 to 2.8 electron Volts. According to my physical
>electronics prof, you can't get an LED with that band gap. That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...

Um...

1) Your Professor if just plain wrong.  Although blue LEDs are one heck of
a lot less efficient than red ones.
2) "Typical visible light LEDs" don't really exist.  LEDs have a fairly
narrow region of transmittence.  (Since the Fermi energy around either side
of the band gap falls off exponentially, blah, blah...)

>Source: Solid State Electronic Devices (Ben G. Streetman, 3d ed., Prentice
>Hall)

You might want to check the copyright date on that. :-)

Blue LEDs most certainly do exist, I've got a bunch at work.  Cree Research
makes them (probably along with other companies...  Cree is big in
materials science, though; they advertise in the stuff like Physics Today,
etc.).  You can buy them from JameCo (I think), DigiKey (definitely), and
plenty of other distributors.

Actually, these days you _can_ get a "typical visible light" LED -- it's
called a "rainbow LED", and I've forgotten who makes it (they advertise in
EDN and many of the other trade rags, though).  It combines a reg, green,
and blue LED all on one chip (and has four leads).  Nifty device, although
it's probably fairly expensive.

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 54145
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Long distance IR detection

sburton@dres.dnd.ca (Stan Burton) writes:..........
> I would like to be able to detect the angular position (low accuracy) of an
> IR emitting source at a distance of about 100 meters (more is better) in
> daylight.  The IR source could be emitting a signature; I'm leaning toward
> 30 KHz square wave with 50% duty cycle.
> 
I designed and built hardware in 1988 that would output a logic level (from
a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
variations in sunlight (and 60Hz from lights). Used no lenses.

Allen Sullivan




Newsgroup: sci.electronics
document_id: 54146
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Power, signal surges in home...

> Though, 1500 real watts still isn't impossible.  About 125-150A with
> a 12V alternator, less if the alternator produces higher voltages.

Anyone claiming that 1500 "real watts" isn't possible in a mobile should
dig through their back issues of 73 (and, I think, QST) for a description
of the mobile installation of that most revered of OMs, W6AM.  As I recall,
this included a Heath 1kW (DC in) amp (what was that model number...SB-
something....  my mind is turning to the usual Friday mush...) and was run 
full-out CW fairly regulary.  The car's electrical system had been modified, 
including a rather seriously-heavy-duty alternator, but such an installation 
HAS been done, and so IS possible.  This installation was the source of
the legendary story of W6AM sitting in the car, and paging his wife over the
department store PA systems!


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
document_id: 54147
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

> >Please explain how cement is able to maintain a lower average temperature
> >than dirt.  Sheesh.......
> 
I hope David isn't going to be too upset with me for sticking my nose
in here again, but here goes......:-)

It isn't the average temperature that is the key factor here, but rather
which is better at transferring the heat out of the (presumably warmer
than ground temperature) battery.  Call it a question of thermal
conductivity, or of insulating ability, or "thermal mass" - whatever you
like.  Question - why does a concrete floor feel cooler than the 
surrounding dirt when you place your hand on it?


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
document_id: 54148
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Switching PS questions

> 	Anyways, I've built the basic up & down converters with pretty
> 	good results (>80% efficiency) but I'm running into problems
> 	when I try to design & build anything that puts out serious
> 	amps... I know it can be done (I have some 5V@200A guts on my
> 	bench) but something puzzles me: I'm using a simple choke as 
> 	the storage element (basicly a toroid with a single winding)
> 	but ALL commercial models use transformers with MANY windings.
> 	I traced a few and they seem to use some of the winding for
> 	the usual error/feedback but some of the others seem to loose
> 	me... What are they for? Better than that, anyone have a full
> 	schematic for one of these that I could get a copy of? I'd
> 	love to see how they manage to squeeze out so much from such
> 	low volume :-)

Most commercial switchers do NOT use magnetics for their energy storage;
that's handled by the big caps on the primary side, those which in a 
linearly-regulated power supply would be considered the "filter" caps,
coming right after the bridge.  The transformer is just that - a 
transformer.  It's there primarily to step the voltage up or down.  (Although
the inductance seen by the switch transistor on the primary side is NOT
negligible, as anyone who's zapped said transistor from either failing to
get one with a high enough breakdown voltage or neglecting to include a
"snubber" diode across it would tell you.  Actually, many transistors intended
for switcher use today have the diode built in.)

The basic switched-mode power supply operates something like this (in
a somewhat simplified manner):  The AC line is rectified to produce a
high voltage, more-or-less unregulated DC rail.  The energy storage (or
"filter") caps appear across this rail, as does the switching transistor.
The transistor chops the current into the primary side of the transformer,
resulting in stepped-up or stepped-down pulses out the secondary, which 
are then rectified and filtered.  At least one of the transformer's outputs
is sampled and fed back to the control circuit for the switching transistor,
which acts in a "pulse-width modulation" (PWM) fashion to control (by varying
the pulse width) the amount of energy being dumped into the primary, and
therefore the voltage coming out at the secondary.  The remaining outputs
may be allowed to simply run at whatever value they will, more-or-less
tracking the regulated output, or they may have some additional linear
regulation added.  You may also note that the feedback between the 
regulated output and the PWM control (which is most typically an IC)
is not done via a direct electrical connection; this is due to various
safety standards which require primary and secondary circuits to be
electrically isolated.  Often, the feedback path involves an optoisolator
to meet this requirement.

While the transformer isn't the primary energy-storage device in these
designs, this does not mean that the energy stored in the transformer can
be ignored; besides the inductive "kick" giving the switch transistor a
bad time (as noted above), you also need to worry about getting all the
energy that went *in* to the transformer back *out* again, one way or another.
In some designs, this happens more or less automatically - but in others,
you need to take special care to ensure that the transformer core doesn't
saturate, which again would have disastrous results (best left to the 
imagination! :-)).

I'm NOT by any stretch of the imagination a power-supply designer; 
hopefully, a real one will come along soon and clean up any gross errors
in the above.


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
document_id: 54149
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does any one know what is biggest ROM for present ?

        Please replay yxy4145@usl.edu
                             Thanks a lot


Newsgroup: sci.electronics
document_id: 54150
From: jmacphai@cue.bc.ca (James MacPhail)
Subject:  Help! Need thermal specs for MC68030FE

I'm doing some work on the Mac IIsi and need some information on the CPU.
I have the Motorola MC68030UM/AD Rev. 1, but I fear it is out of date as it
does not have the characteristics for the CPU package type used in the IIsi.

What I need is the Theta (JC) Thermal Characteristic (the Junction to Case
thermal resistance) for the _PLASTIC_ FE style package.

If you have this info, I would appreciate your sending it by email as postings
suffer a few days delay here.

If you are keen on this stuff, I am also interested in a more accurate value
for the typical power dissipation. I'm assuming 2.25 Watts (using the 2.6 W
maximum at 0 C decreased the way the Pd drops in the 6801x as Ta increases).
If your manual has a chart of power dissipation, I'd like to know what it
reads at 25 C and 40 C.

Thanks for reading!

James MacPhail  jmacphai@cue.bc.ca  (on bounce try james@mirg2.phy.queensu.ca)

Newsgroup: sci.electronics
document_id: 54151
From: ejm@coyote.datalog.com (E.J. McKernan)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.
>

It's NOT the concrete floor that does it. The problem is that lead-acid
cells self discharge over time. Even high quality cells (Gates for instance)
will discharge 50-60% over a 3-5 month period of time. Non-sealed cells
self discharge even faster. If the battery was not completly charged
when left sitting, it probably discharged past the the point where cell
sulfiding occurs, which in many cases means a ruined battery.
-- 
   /|_|\   Datalog Consulting, Tucson, AZ
  ( . . )  ejm@datalog.com
   \   /   ...!noao!datalog.com!ejm
    \_/    

Newsgroup: sci.electronics
document_id: 54152
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Laser vs Bubblejet?

Here is a different viewpoint.

> FYI:  The actual horizontal dot placement resoution of an HP
> deskjet is 1/600th inch.  The electronics and dynamics of the ink
> cartridge, however, limit you to generating dots at 300 per inch.
> On almost any paper, the ink wicks more than 1/300th inch anyway.
> 
> The method of depositing and fusing toner of a laster printer
> results in much less spread than ink drop technology.

In practice there is little difference in quality but more care is needed 
with inkjet because smudges etc. can happen.

> It doesn't take much investigation to see that the mechanical and
> electronic complement of a laser printer is more complex than
> inexpensive ink jet printers.  Recall also that laser printers
> offer a much higher throughput:  10 ppm for a laser versus about 1
> ppm for an ink jet printer.

A cheap laser printer does not manage that sort of throughput and on top of 
that how long does the _first_ sheet take to print? Inkjets are faster than 
you say and in both cases the computer often has trouble keeping up with the 
printer. (I have a 486/33 and a lot of drivers cannot keep up with the 
printer)

A sage said to me: "Do you want one copy or lots of copies?", "One", 
"Inkjet".
 
> Something else to think about is the cost of consumables over the
> life of the printer.  A 3000 page yield toner cartridge is about
> $US 75-80 at discount while HP high capacity (~500-1000 page yield)
> cartridges are about $US 22 at discount.  It could be that over the
> life cycle of the printer that consumables for laser printers are
> less than ink jet printers.  It is getting progressively closer
> between the two technologies.  Laser printers are usually desinged
> for higher duty cycles in pages per month and longer product
> replacement cycles.

Paper cost is the same and both can use refills. Long term the laserprinter 
will need some expensive replacement parts (consumables) and on top of that 
are the amortisation costs which favour the lowest purchase cost printer.

HP inkjets understand PCL so in many cases a laserjet driver will work if the 
software package has no inkjet driver. 

There is one wild difference between the two printers: a laserprinter is a 
page printer whilst an inkjet is a line printer. This means that a 
laserprinter can rotate graphic images whilst an inkjet cannot. Few drivers 
actually use this facility.
(there is also the matter of downloadable fonts and so on)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
document_id: 54153
From: rwong1@ugly.UVic.CA (Richard  Wong)
Subject: Voice synth chips

Does anyone know where I can get some voice synthesis chips??
I am looking for something like the ones that do the time and date
stamp on answering machines.

Newsgroup: sci.electronics
document_id: 54154
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Lead Acid batteries & Concrete?

>   Why does a lead acid battery discharge and become dead (totally unuseable)
> when stored on a concrete floor?  

When will people learn!

The trouble is the ballast in the concrete and as every fool knows Ballast 
resistors are used to discharge batteries. Furthermore it is very silly to 
store the battery with the terminals downwards as you must have done to 
contact the ballast. 

Seriously: self discharge (the actual problem, as stated by others) does vary 
greatly with certain types and freaks show low self discharge. I have in 
fact seen ordinary automotive batteries which have effectively held full 
charge for > 2 years so it must be possible.

If your garage is heated, store the batteries somewhere cooler but above 
freezing (flat batteries freeze more easily). Occasionally charge it (once a 
month?) or even leave it on 'float' charge permanently (special charger, 
DON'T do this unless you know what you are doing, seriously dangerous).

Anouther point is the unsuitability of automotive batteries for things like 
electric mowers -- they are not generally designed to be repeatedly deep 
discharged and their life may be greatly shorted. Some early zero maintenance 
automotive batteries in fact responded to a full discharge with total failure 
shortly afterwards but modern ones are superb. (6yrs, 95000 miles and 
counting)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
document_id: 54155
From: alan@apple.com (Alan Mimms)
Subject: Re: UART needed (really BREAK detect)

In article <3402@tau-ceti.isc-br.com>, jimc@tau-ceti.isc-br.com (Jim
Cathey) wrote:
> 
> In article <alan-210493163447@17.129.12.26> alan@apple.com (Alan Mimms) writes:
> >Actually detecting a BREAK is done by watching for a "character" containing
> >all zero bits with the framing error resulting from its receipt.  This
> 
> True enough, but...
> 
> >means that the line stayed in the zero bit state even past the stop bit
> >time slot, which basically indicates a BREAK.  There is no special way to
> >detect BREAK that I have found other than this -- there's no magic signal
> >generated by UARTs, etc.
> 
> Zilog SCC:
> ---------
> 	RR0[7]:  Break Detect
> 
> This is a very popular part, but it has a number of quirks, especially
> in HDLC mode.
> 
> Signetics 68562 DUSCC:
> ---------------------
> 	RSR[2]:  Break Start Detect
> 	RSR[3]:  Break End Detect
> 
> Two of the bits in the Receiver Status Register.  You can enable an interrupt
> on either of these bits going high, too.  Also, only one NULL will be put
> in the FIFO per break detected.
> 
> This is simply the best serial chip I've ever worked with.  _Many_ less
> quirks than the SCC, which is IMHO second-best.  (Death to 8250 devices!)
> 

And I thought I knew a lot about serial devices.  Perhaps I should just
keep my big mouth shut.  Sorry.

Alan Mimms (alan@apple.com, ...!apple!alan)   | My opinions are generally
Portable Macintosh Software Group             | pretty worthless, but
Apple Computer                                | they *are* my own...
Art without engineering is dreaming.  Engineering without art is
calculating.
	-- Steven K. Roberts in "Computing Across America"

Newsgroup: sci.electronics
document_id: 54156
From: cpuig@infoserv.com (Carlos M. Puig)
Subject: Re: Analog switches/Balanced Demodulators

msf@skaro.as.arizona.edu (Michael Fulbright) writes:

> I am trying to build a synchronous demodulator and I've hit a snag.
> In my application I want to be able to change the gain of an
> op amp amplifier from 1 to -1, controlable via a digital input.
> The most obvious way I've come up with is to use analog switches
> to adjust the gain of the op amp. The only analog switch I have
> experience with it the 4066. Unfortunately I want to switch an
> AC signal which goes from about -5V to 5V, and the 4066 is only
> for positive signals.
>

     I have recently used the 4066 to switch a bipolar signal.  I simply
ran the 4066 off a bipolar supply, +/- 8V in this case.   As long as your
analog input signal stays between the supply rails, the 4066 will work fine.
Of course, your control (logic) input must use -8V as the logic LOW and
+8V as the logic HIGH reference, so that either (1) all your driving logic
must be 4000 CMOS with the same bipolar supply or (2) you must provide
some kind of voltage level shifting circuit between the 4066 and the
control logic.  In my case, I was able to use the bipolar supply all the
way.


----
Carlos Puig, KJ6ST             cpuig@infoserv.com
San Jose, CA                   (408) 289-8174

Newsgroup: sci.electronics
document_id: 54157
From: dmn@kepler.unh.edu (There's a seeker born every minute.)
Subject: flash LEDs with sound?



     I'm looking for a circuit that will flash an led on in response 
to the output from a walkman cassette player. How could I do this?
I don't want it just to turn on, I want it to 'strobe' once so to speak,
per every beep I put on a cassette tape. 

     Would it be better to use a circuit based on the volume of the beeps
on the cassette, or better for the leds to respond to a tone of a certain
frequency? Is there any easy way to do either of these? I'm looking for 
the simplest circuit possible. I guess what I'm asking for is some sort of
color organ, but not quite. Let me trt to explain again...


     I'm going to have a pattern of beats (or beeps) on a cassette tape.
So on the tape you'd hear:   beep! (pause) beep! (pause) beep! (pause)..etc. 
, with speed increasing as time goes on. I want to synchronize an LED (
probably two of them) with the beeps on the cassette tape. So the LED, with
each beep, would go on and off real quick, generating a strobe light sort
of effect. The rapidity of the beeps on the tape would in turn effect the
rapidity of the blinking of the LEDS. And if there was no sound on the tape
(except for background his), the LEDs would remain off. Please help!


  Thanks,

    Dana



Newsgroup: sci.electronics
document_id: 54158
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Re: Blue LED's

In article <Zw6F3B1w165w@inqmind.bison.mb.ca> Baden de Bari,
baden@inqmind.bison.mb.ca writes:
>Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
Hosfelt
T-1 stock # 25-214
T-1-3/4   # 25-213
Both $1.29 - Vf 3.0..3.4, 470nm, 3mcd @ 10ma, Mfg Liton
Call 1-800-524-6464
Disclaimer - dont know these guys from a bar of soap, but the price
looks reasonable.

Newsgroup: sci.electronics
document_id: 54159
From: rick@cs.sunysb.edu (Richard Spanbauer)
Subject: Re: Luser!

In article <1993Apr23.205257.10578@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for a very high speed 
>D/A converter (at least 8bits and 150MHz) for
>a research application. A paper in  the January
>issue of IEEE Solid-State Circuits mentions a 
>GaAs, 1GHz, 8bit DAC - anyone know where I can find
>such a thing? Even a somewhat slower Si DAC would
>do.
>	Needless to say, I have looked in all the
>conventional places (Vitesse, Motorola, National,
>etc. etc.). Any pointers would be appreciated.

	Think video.  Brooktree sells a whole line of DACs that can
	be used, normally for graphics applications, in either 50 or
	75 ohm systems.  For example, the BT468 can be had in speeds
	up to about 200 mHz, BT492 to 360 mHz, and 400 mHz with the
	BT109.  

>--- Seema Varma

					Rick Spanbauer, 
					SUNY/Stony Brook

Newsgroup: sci.electronics
document_id: 54161
From: glynnet@zero.cypher.com (Glynne Tolar)
Subject: Re: Laser vs Bubblejet?

In article <735446880snx@black.demon.co.uk> tchannon@black.demon.co.uk writes:

>There is one wild difference between the two printers: a laserprinter is a 
>page printer whilst an inkjet is a line printer. This means that a 
>laserprinter can rotate graphic images whilst an inkjet cannot. Few drivers 
>actually use this facility.
>(there is also the matter of downloadable fonts and so on)
>
>  TC. 
>    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
>                                

I have a DeskJet 500 and I thought I'd give a little info.  The DeskJet 500 WILL
do landscape mode like the HP LaserJets.  I can't say if other inkjets do
though.  Also the DeskJet can do downloadable fonts ONLY if you buy a softfont
memory cart for it.  OH!  You said the LaserJet can rotate a graphic image!
Hmmmmm!  The DeskJet can only rotate text.  Nevermind!
 

Newsgroup: sci.electronics
document_id: 54162
From: dmn@kepler.unh.edu (There's a seeker born every minute.)
Subject: blinking LEDs?



   Where can I buy blinking LEDs besides radio shack? 


  * Does anyone sell blinking LEDs with variable flash rate? (by voltage
    I guess) If so, what hertz (pulse) rate are they adjustable or set to?

     I'd like blinking LEDs that can be set for approx 5 hz, 10 hz, 
     15 hz, or 20 hz. Something like that... I'm interested in what's
     out there for flash rates. I like the idea of LEDs with flasher 
     circuits already in them. I hate soldering ICs in general. Guess I
     don't have a hell of a lot of patience. 


      Thanks,

         Dana


Newsgroup: sci.electronics
document_id: 54163
From: mmoss@ic.sunysb.edu (Matthew D Moss)
Subject: How do you build neural networks?


Subject says it all, though I should specify that I'm looking for solutions
that DON'T require me purchasing specific chips, etc....

In other words, is there some sort of neural network circuit I could build
after a visit to a local R-Shack?
-- 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Matthew David Moss		| Blessed are the pure in heart, for they     |
| INTERNET: mmoss@ic.sunysb.edu	| will see God.                               |
| BITNET  : mmoss@sbccmail	|                                 Matthew 5:8 |

Newsgroup: sci.electronics
document_id: 54164
From: dhollman@phage.cshl.org ( CSHL)
Subject: Re: How to the disks copy protected.

I think a few things are being missed overall here... First of all, anyone
with a DOS manual can copy a disk, or copy anything (hidden files dont
go far if you are dealing with anyone who is not comletely DOS ignorant) off
of a hard disk. 'Professional' crackers aren;t interested in copying disks.
They are programmers who get some thrill out of going through unassembly
listings of programs to disable copy protection such as serial number
dialog boxes, volume label checks, and who knows what when it comes to
computer games. 
    
Those people are in the minority, however. In my experience with the world of
people and software, it seems that a good majority of people (say 80%) will
at some point copy a friend's program ("Gee, you really oughta try this") or
accept a copy. These are people who normally would buy a software package
or do without, but decided that just once it wouldn't matter.

The last thing is people who own or are responsible for more than one 
computer; most people aren't going to spend $150 * X# of computers for the
same software package.. they will just install it x# of times, especially
things like DOS upgrades.

-- 
|-----------------------------------------------------------------------------|
|    Are we having fun yet?                                                   |
|-----------------------------------------------------------------------------|

Newsgroup: sci.electronics
document_id: 54165
From: <U19250@uicvm.uic.edu>
Subject: multiple inputs for PC

Can anyone offer a suggestion on a problem I am having?
I have several boards whose sole purpose is to decode DTMF tones and send
the resultant in ASCII to a PC.  These boards run on the serial interface.
I need to run * of the boards somwehat simultaneously.  I need to be able to ho
ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
PC inexpensivley, so that all can send data simulataneously (or close to it)?
Any help would be greatly appreciated!
Abhin Singla

Newsgroup: sci.electronics
document_id: 54166
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: multiple inputs for PC

In article <93114.142835U19250@uicvm.uic.edu> <U19250@uicvm.uic.edu> writes:
>Can anyone offer a suggestion on a problem I am having?
>I have several boards whose sole purpose is to decode DTMF tones and send
>the resultant in ASCII to a PC.  These boards run on the serial interface.
>I need to run * of the boards somwehat simultaneously.  I need to be able to ho
>ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
>PC inexpensivley, so that all can send data simulataneously (or close to it)?
>Any help would be greatly appreciated!


Are the boards at all intelligent?  (I.e., run by microcontrollers?)  The
easiest thing would be to have another line that says that one of the
boards is talking to the PC.  When this line was true, the other boards
could all hold off and not send their data.  This isn't a perfect solution,
though, since you have to worry a little about making sure two boards don't
decide to talk at the _exact same time_.

Other than that, I think you will need to hook up each board to "something"
that speaks RS-232.  This actually isn't as hard (or as expensive!) as it
used to be, though.  Assuming the boards talk relatively slowly (9600 BPS
or slower), the PICs can coordinate things between themselves to multiplex
the data.  (This is really just forbicly adding the suggestion in the first
paragraph to your system.  And it assumes that each board doesn't talk more
than 1/8th of the time, of for very long, since a PIC isn't going to be
able to buffer more than, maybe 20-some bytes!)

You might want to check into the prices of multi-serial card for your PC,
though.  I recently bought a Boca Research 2x4 card (2 parallel ports, 4
RS-232 ports) for a very reasonable $85.

					---Joel Kolstad

Newsgroup: sci.electronics
document_id: 54167
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Self-destructing copy protection on VHS tape?

In article <klp.735603389@quark> klp@doe.carleton.ca (Ka Lun Pang) writes:
>
>I borrowed a VHS tape from a friend and it has a warning in the begining saying
>that attempts to copy the tape will result in destroying the copy and the
>original. I found this unbelievable as playing and recording are two different
>processes. However, I've never seen this tape being sold anywhere so I don't 
>want to take the chance even it's small.
>
>Anyone has experience in this kind of self-destructing video tapes?
>

I have always thought that if I wanted to send the Police a tape with
a ransom demand on it, or send CNN a video tape to see if they wanted
to buy it, I would place a small magnet near the take-up spool so the
tape would be erased as it was played. Who would think to check?

John


Newsgroup: sci.electronics
document_id: 54168
From: mcorbin@oucsace.cs.ohiou.edu (Max Corbin)
Subject: 1-bit A/D converter

Once upon a time, long long ago in this news group, someone
posted a schematic for a 1-bit A/D converter.  Well I just found a use
for the little monster.  Anyone out there still got this text file?
It had a flip-flop, a resistor and a cap, and a comparator/op-amp I 
think.  I would be extremely thankful to anyone who could mail me the 
schematic or post it to the news-group.



-- 
+-----+---\ +-----+ 	O O 	Beware the light at the end of the
| | | | -- >|  ---+	 +	tunnel.  It may be an oncoming Dragon.
+-+-+-+---/ +-----+     \_/
   M   	 D     C	 U      mcorbin@oucsace.cs.ohiou.edu

Newsgroup: sci.electronics
document_id: 54169
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>
>That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...
>
Sorry Charlie...

I have a dozen, VERY blue LED's on my bench right now. They have
a clear plastic case and when lit, are absolutely BLUE. The hue
is sort of a "summer day cloudless sky blue" but make no mistake,
they are blue.

You can buy them from Digikey, Circuit Specialist, Jameco (I think),
LED-Tronics, Stanley Optoelectronics, and others. The current price
is around $2.50 each for small quantities. I will also be selling
them through my mail-order company in the near future (4 weeks).
Write for details if interested.

John




Newsgroup: sci.electronics
document_id: 54170
From: ez019654@othello.ucdavis.edu (Victoria Milliron)
Subject: Re: How to the disks copy protected.

Hmmm...
  A possibility for the software registration conondrum would be to have the
distributor register the copy when the software was sold.  The clerk sticks it
in the store PC and asks for the buyers ID. Later, if pirated versions showed up they could be tracked to the original purchaser. In addition copies which were
sent to distributors/stores would have a vendor reg # or serial # in order to
track in store piracy.

Possible additional program security schemes would be:
1. having monthly password changes which necessitate user call in
   and registration. (inconvenient)
2. taking dire legal action on anyone caught (expensive)
3. encryption, crc check, self modifying code (limited effectiveness)
4. have an independent watchdog program in the installation/setup config or
   memory manager, etc. which would check the main program's crc. 
   (only as effective as above methods at best.)
5. have the above watchdog circulating as a virus which would trash cracked 
   copies of the program and/or the offenders hard drive. (risky, and probably
   illegal, certainly immoral)

my new ideas aren't terribly feasible to implement as presented, but I thought
if I threw them out people could think of variations that might be effective.
What is the problem with parallel port security keys? I haven't used anything
that had hardware key copy protection schemes, so I don't know what the
drawbacks are. I know the companies that make them claim they're uncrackable,
but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
so don't ask) and I had heard that it had parralel port keys.

vamilliron@othello.ucd.edu
-my apologies if I rambled, but vi inhibits my communication skills greatly.

Newsgroup: sci.electronics
document_id: 54171
From: dasmith@sunburn.ec.usf.edu. (David Smith (GE))
Subject: Re: Laser vs Bubblejet?

Inkjet and Bubblejet printers are the same tech.  "Bubblejet" was trademarked
by Cannon and inkjet was by HP I belive.  I have seen both, and own a 
"bubblejet" (a Apple StyleWriter which has a cannon engine) with a 360 dpi
rated output.  The output is very good with quality paper, which is
very importaint.  Cheap paper gives bad results.  I use sealed paper and
the only differenc is that the ink is less dark than toner (I compaire
to the Apple Personal LaserWriter NTX), but then again the difference
is $300 to $1500 so....

--
/------------------------------------------------------------------------------
| David A. Smith               | "I like to skate on the other side of the ice"
| - dasmith@suntan.ec.usf.edu  | I Didn't do it, And I don't know anything  
| - smithd@eggo.csee.usf.edu   | either. USF better not know I'm here :) 

Newsgroup: sci.electronics
document_id: 54172
From: belvilad@dunx1.ocs.drexel.edu (A. Belville)
Subject: Re: flash LEDs with sound?

In article <199304241405.AA11067@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:
>
>
>     I'm looking for a circuit that will flash an led on in response 
>to the output from a walkman cassette player. How could I do this?
>I don't want it just to turn on, I want it to 'strobe' once so to speak,
>per every beep I put on a cassette tape. 
>
>     Would it be better to use a circuit based on the volume of the beeps
>on the cassette, or better for the leds to respond to a tone of a certain
>frequency? Is there any easy way to do either of these? I'm looking for 
>the simplest circuit possible. I guess what I'm asking for is some sort of
>color organ, but not quite. Let me trt to explain again...
>
>
>     I'm going to have a pattern of beats (or beeps) on a cassette tape.
>So on the tape you'd hear:   beep! (pause) beep! (pause) beep! (pause)..etc. 
>, with speed increasing as time goes on. I want to synchronize an LED (
>probably two of them) with the beeps on the cassette tape. So the LED, with
>each beep, would go on and off real quick, generating a strobe light sort
>of effect. The rapidity of the beeps on the tape would in turn effect the
>rapidity of the blinking of the LEDS. And if there was no sound on the tape
>(except for background his), the LEDs would remain off. Please help!
>
>
>  Thanks,
>
>    Dana

	Try looking in a Magizine called Radio Electronics, May 1992 issue,
page 41.  There is a circuit for a Midi Light controller there.  

-=- Andy -=-

_______________________________________________________________________________
Andy Belville                          || It's taken me a long time, but I've
belvilad@dunx1.ocs.drexel.edu          || fallen in Love with a beautiful woman.
_______________________________________________________________________________

Newsgroup: sci.electronics
document_id: 54173
From: tsjoit@htsa.aha.nl (T. H. Tsim)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


>>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>>	Hello again,
>>> I asked this a year ago, but i am still looking.
>>> I am getting sick of having to use a HC373 

I didn't catch your posting one year ago, but I presume you like to leave out
an extra a-latch ? (I presume you allready know there is a '573 but that couldnt
be the question, could it ? ;-)

During my student-trainee project, I discouvered a nice device, it's a PSD301  
from Waferscale Integration. In one single (44 PLCC I think it was) package
it contained: ROM, RAM, I/O lines and a programmable addressdecoder...

As far as I can recall, it can be hooked directly with a MCS-51 series uP ... 
Neat huh ? But it needs programming before assembly, so it wasn't suitable
for my project. Perhaps usefull for you (future) plans ?


Greetings!


Newsgroup: sci.electronics
document_id: 54174
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Self-destructing copy protection on VHS tape?

klp@doe.carleton.ca (Ka Lun Pang) writes:

> 
> Hi folks,
> 
> I borrowed a VHS tape from a friend and it has a warning in the begining sayi
> that attempts to copy the tape will result in destroying the copy and the
> original. I found this unbelievable as playing and recording are two differen
> processes. However, I've never seen this tape being sold anywhere so I don't 
> want to take the chance even it's small.
> 
> Anyone has experience in this kind of self-destructing video tapes?
> 
> Thanks in advance.
> 
> --
> Ka Lun  Pang (a.k.a. Andy) - Lost between frequency and time on the unit circ
>                       email: klp@doe.carleton.ca 
>                                DoD# 0687


To put it bluntly, they are full of it.

Paying a tape is playing a tape.  There is no difference whether the 
output goes to a second VCR or to a TV.  (How the VCR or TV reacts to 
this signal is a different story - see messages pertaining to macrovision 
copy protection.)

In order for the tape to self-destruct, it would have to have circuitry 
of its own within the tape case.  The circuit would have to somehow 
magically determine what the output of the VCR is connected to.  The 
circuit would then have to have an erasing head to actually do anything.

It is a pretty lame scare tactic.  (I've seen something similar on a BBS.
When the SYSOP wanted to, he could have a message sent to the user's end 
saying that it is sending the code to format your HD.)


victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54175
From: <LEEK@QUCDN.QueensU.CA>
Subject: Re: How to the disks copy protected.

In article <C60DvH.FAn@ucdavis.edu>, ez019654@othello.ucdavis.edu (Victoria
Milliron) says:
>
>  A possibility for the software registration conondrum would be to have the
>distributor register the copy when the software was sold.  The clerk sticks it

That's kind of extra work that one cannot expect the store people to do.
IMHO it would be easier if companies sell their software as cheaply as
possible AND to sell the customers detail manuals (for the brain-deads)
, quick reference books, how to do books and videos, paid support hot line
(1-900 :).  For the registered purchasers, these can be part of their package.
I have seen many books to teach people how to use DOS, WP and other software.  I
I suspect either users can't read the manuals or they don't have manuals.
Either way, there is $$$ to be made.   BTW books are quite a bit more
expensive to reproduce than a $1 disk.

>What is the problem with parallel port security keys? I haven't used anything
>that had hardware key copy protection schemes, so I don't know what the
>drawbacks are. I know the companies that make them claim they're uncrackable,

With the popularity of Multitasking and pseudo multitasking systems
(eg. OS0.5, Windoze, Mack System 7), it is pretty easy to run a debugger
and figure out the protection schemes by disassembling/tracing/trapping
the application during run time.  Schemes like compressed software/
special loaders would be easy pray even to beginner hackers.

Hardware keys (unless well designed and *TOTALLY* transparent) is a
pain in the b*t.  We having using a piece of software under Windoze
that uses a hardware key.  The key interfers with the printer stuff
with other programs and often has to be unplugged for those software
to work properly.

>but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
>so don't ask) and I had heard that it had parralel port keys.

All the hacker has to do is to remove/modify code that communicate with
the port.

>vamilliron@othello.ucd.edu
>-my apologies if I rambled, but vi inhibits my communication skills greatly.

K. C. Lee
Elec. Eng. Grad. Student
OS0.5, Windoze, Mack are not trademarked...

Newsgroup: sci.electronics
document_id: 54176
From: ree88132@zach.fit.edu (Keith Ledig)
Subject: needed: 120v 3watt fan

Can someone tell me where to find 120volt 3 watt 40 mA fans that
fit the standard computer mounting size )ie. 3 and 1/8 inch wide
and 4 inches diagonal from hole to hole (hole=where bolt or screw
goes through.  I have found higher (NOISY) fans that are 120 v
6 watt, but I need a quite fan.  I can use 12 volt as well, but
found just about all 12 volt fans to be noisy.  I also find that
the 120 v fans are not only quieter, but the blade shape has a lot
to do with it.  I have a dead fan that was quiet in it's day.  It
has long blades (like fan blades in a tturbo engine on a jet is
the only way I can describe it.  The dead fan is ETRI Model 126LH.
Actually it's not dead, it just makes a hideous rattle noise so
it's stealthy qualities are void.  Thanks.



Newsgroup: sci.electronics
document_id: 54177
From: nelson@sun.soe.clarkson.edu (Russ Nelson)
Subject: Proposal: alt.fan.tesla

For discussion of Nikolai Tesla (who else??)

--
--russ <nelson@sun.soe.clarkson.edu> Businesses persuade; Governments force.

Newsgroup: sci.electronics
document_id: 54178
Subject: PC BOARD Layout Help
From: <EH1QC@CUNYVM.BITNET>

Hi,  I have a few questions about laying out a PCB. I am using easytrax for dos
which is a great program. But what my question is When laying out traces what
thickness should they be? I am mainly designing low voltage low current boards
for micro controller apps. What should pad sizes be for resistors? I will be
turning to a commercial PCB maker to produce 1's of these boards and I was
wondering what is the minimum distance traces should be from each other. Well
any info would be great. Thanks.
                                                 Anton

Newsgroup: sci.electronics
document_id: 54179
From: dws30@p1hdb01cd.amdahl.com (David Sharpe)
Subject: Re: Pink Noise


 Pink Noise and White Noise are equal amounts of all frequencies.  This
is in most cases around the 20-3.3K Hz range.  Pink/White are used to
adjust for room dynamics and stuff like that.  There are a few EQ's out
on the market that have Pink noise built in.  Most all from Audio
Control have them I know the C-101 does.  

Newsgroup: sci.electronics
document_id: 54180
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Hi Volt from battery

In article <C5uFIG.1Dv@news.cso.uiuc.edu> martyj@mrcnext.cso.uiuc.edu (martin johnson) writes:
>I need a small battery powered hi voltage capacitive discharge supply to
>deliver ~6 joules at 250 volts...  the ubiquitous
>camera flash circuit is what I want, but I cant get mine apart without
>breaking it...

Charlie Brett's suggestion -- buy one of the disposable flash cameras, use
the film, then take the thing apart -- is a good one.  Note, though, that
you won't get a particularly precise voltage out of such a thing, and it
may be a single-point design that won't adapt well to off-nominal operation.

The things are easy to dismantle.  The key piece of information is that
when you advance the film on one of them, you are winding it *into* the
film cassette -- it is unwound from the cassette in the factory, when
the camera is made.  So no darkroom is needed for dismantling.  It's
standard film, so just take the cassette in for processing.

All the camera-store people do when you bring in one of the disposables
is rip it apart, toss the film cassette into the to-be-processed bin,
and throw the battery in one trashcan and the rest of the camera in
another.  If you take it apart yourself, you get an AA alkaline battery
(still with a fair bit of life in it) and all kinds of little bits and
pieces from the camera.

I expect you could even re-load and re-use the camera if you were really
determined.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 54181
From: camter28@astro.ocis.temple.edu (Carter Ames)
Subject: Lead ACid Batteries PART 2!!!


   I thought the first thread was hilarious, so here goes another post.

Some more background information on what has happened to my poor batteries.

  One year, I left the batteries in the garage.  The garage is Unheated.  
They were left in their places that they needed to be.  One in the riding
lawnmower (what a lux) and one in each motorcycle.  The battery in the 
riding lawnmower was about 3-4 years old, and one of the cycle batteries 
was new, and one was around 5 years old.  Upon spring time, I discovered
that all of the batteries were dead, and needed to be recharged.  They all
worked properly, except for the older ones, and they had to be replaced 
about halfway through the summer.  (they had originally been stored
in the garage, and I think I remember my dad charging them in spring)
  Last year, I decided to bring them in to the basement, which has two parts.
one is dirt and brick, and the other is concrete.  I brought in all three, and
discovered in the spring, (about 15 days ago) that not only were the batteries
dead, but when I put the charger on them, the charger said "HMMMMMMMM" and 
the amp-meter read around 1,000,000,000  (In other words, it was pinned)
the internal circut tripped, and I went on to the other batteries.  They
were the same.  
   Realizing that we still had 2 GIGANTIC sailboat batteries, also lead
acid, I decided to put the charger on them.  (these had been sitting for around 1 and a half years, on the brick and dirt part) and noticed that they only
needed a small charge, around 2 hours or so on trickle.  I tested them
by using them at the local gas station for giving jump starts, and they
worked fine for around 25 of 'em. 
  This leads me to believe one of several things.
     1) I bought really #$%tty batteries last year. (sorta true)
     2) the concrete has something to do with the discharge of the
        batteries.
     3) There was enough moisture to short out the terminals in the 
          room where the concrete is, 
     4) The dirt room was able to absorb the moisture in the air
         better than concrete.

(BTW, I can almost waterski in the dirt room)  

   Any other ideas?
    *could be the aliens, anything is possible.*
 

Newsgroup: sci.electronics
document_id: 54182
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

In article <7480241@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>It isn't the average temperature that is the key factor here, but rather
>which is better at transferring the heat out of the (presumably warmer
>than ground temperature) battery...

Uh, Bob, why is the battery warmer than ground temperature?  On the time
scales in question, and with the considerably reduced temperature swings
several feet underground, there isn't going to be any major temperature
difference between the battery and what it's sitting on.

>... Question - why does a concrete floor feel cooler than the 
>surrounding dirt when you place your hand on it?

Because the temperature of your hand, *unlike that of the battery*, is
determined by the balance between internal heat production and external
heat loss.  You're feeling the greater rate of heat loss from an object
(your hand) which is kept much warmer than its surroundings.  In the case
of an object with no significant internal heat production, this will
affect how quickly it comes into equilibrium with its surroundings (if
it started out not in equilibrium with them) but won't affect the final
temperature.

For the same reason, windchill affects whether you will freeze but not
whether water will freeze.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 54183
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: How to the disks copy protected.

In article <C5x75A.48H@ms.uky.edu>, msunde01@mik.uky.edu (Mark  Underwood) writes:
> In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
> (Eric Richard Noel) writes:
>> I hate hard copy manuals, and would rather have all docs online - *not*
>> because I want to copy the program, but because its usually faster and
>> and convenient than sifting through an old book I can't find.
> 
> Just MHO, but I prefer hardcopy books because you can have three or four  
> of them open spread across the bed (next to the desk in my dorm) and  
> reference them while using the program full-screen.  The Windows Help  
> things come closest to good on-line documentation I've seen, but they  
> generally aren't detailed enough and would probably take a LARGE amount of  
> space (even compressed) which is at a premium on my system . . ..  In  
> fact, the manuals are the primary reason I bought Borland's C++ compiler  
> instead of using the one the lab licensed (in the lab, of course).  I've  
> got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
> his own . . . :-)
 
It is also much easier to scribble corrections on a hard-copy manual.
 
Jeff White     jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
document_id: 54184
From: belvilad@dunx1.ocs.drexel.edu (A. Belville)
Subject: Circuit List (locations)


	Here is a list I get when I was combing through some microfilm one
day here at Drexel while completely board.  Most of these circuits are
pretty easy to constuct and can be done by a novice.
	This is basically some stuff that could prove useful to you without
having to sit down and either design or buy the stuff (not a good word, but I'm
tired right now).
	Hope you enjoy!

	If you have any additions send them to me and I'll add them to the list
.  They don't have to be from this particular magazine, they just have to be
interesting!

	RADIO ELECTRONICS

Year	Month	Page	Article Name and/or discription
----------------------------------------------------------------------------
92	April	31	Car Audio Amplifier (270 Watts)
	May	41	Midi Light Controller (Light control from music input)
		47	Solid State Relay 
		50	Digital Altimeter
	June	53	Electronic Thermostat
91	February43	Audio Sweep/Marker Generator (frequency response)
	April	43	Line Power from 12 volts (12 VDC -> 110 VAC) (40 Watts)
	June 	39	Electronic Compass
	August	55	Speaker Protector
	Sept.	33	Solid State Tesla Coil
	Oct.	39	Vocal Effects/Mixer
	Nov.	58	Music on Hold (Play music for someone who is on hold on
				the phone)
	Dec.	47	THD Analizer
		53	Battery Tool
		63	Electronic Fuse
90	Jan.	35	Acoustic field Generator
		45	Phone activated Audio Muting circuit
	Feb.	31	Frequency Probe
		37	Radar Detector Tester
	March	31	Universal Laboratory Power Supply
	April 	33	Morse/RTTY Detector
		43 	Capacitance Adaptor (Capacitance add on for a DMM)
		46	Solid State Wiper control
	May	37 	Universal Descrambler (for a TV)
	July	31 	Digital Dashboard (for a car)
	August	41	Digital Pressure gauge
	Sept.	33	Vocal Stripper (take the vocals away from music)
	Oct.	37	Rocket Altimeter (model rockets)
	Dec.	33	Benchtop Frequency counter
89	Jan	55	Carrier-Current Audio transmitter (audio through your
				house's wiring)
		62 	Plasma display globe
		70 	Advanced Control System
	Feb.	55	Carrier-Current Receiver
	March	51	Hi-Fi Audio Amp for House or Car (High Power)
	May	41	I-R Extender (extender for Infra-Red remotes)
	July	31 	Light beam communication
		38	Digital Capacitance meter
	Nov	39 	R-C Decade Box 
		43	Digital Compass
	Dec	37	Programmable Phasor Property Guard
88	July	41 	L-C Meter Part 1
	August 50	L-C Meter Part 2
87	Nov.	107	Electronic Combonation Lock
86	Sept	41	Stun Gun
	June	55	Click and Pop filter for your stereo (removes clicks and
				pops when you play old LPs)

-- From what I could see, you can order the circuit kits, finished or unfinished
	or you can order the parts that you can't get through a normal store

_______________________________________________________________________________
Andy Belville                          || It's taken me a long time, but I've
belvilad@dunx1.ocs.drexel.edu          || fallen in Love with a beautiful woman.
_______________________________________________________________________________

Newsgroup: sci.electronics
document_id: 54185
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: How do you build neural networks?

mmoss@ic.sunysb.edu (Matthew D Moss) writes:.........
> In other words, is there some sort of neural network circuit I could build
> after a visit to a local R-Shack?
Marvin Minsky (hi there) writes of building "perceptrons?" in the 1950s using
motor-driven potentiometers to vary the weights. He reported that the circuits
worked even tho there were wiring errors. (Can you say ROBUST?)

Cadium Sulfide cells vary with light. CMOS or TTL gates provide the SIGMOID
somewhat-linear-yet-somewhat-limiter transfer function often used. 
Low power Schottky gates, and earlier gates, has about a gain of X8.
LEDs probably output enough light to easily control CdS cells, even at a
few mA. And paper with dark and light regions, controlled by pencil and
eraser, could also control CdS resistance. The very high input resistance of
CMOS gates may let you charge up 1uF paper/mylar caps to serve as memory.

Allen Sullivan

Newsgroup: sci.electronics
document_id: 54186
From: then@snakemail.hut.fi (Tomi  H Engdahl)
Subject: Re: flash LEDs with sound?

In article <199304241405.AA11067@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:

>     Would it be better to use a circuit based on the volume of the beeps
>on the cassette, or better for the leds to respond to a tone of a certain
>frequency? Is there any easy way to do either of these? I'm looking for 
>the simplest circuit possible. I guess what I'm asking for is some sort of
>color organ, but not quite. Let me trt to explain again...

Look for information about 567 tone decoder chip. It is an easy to use
chip for detecting sound of certain frequency. You need only one
567 and some other componets for each led you want to control.
The chip can take the voltage levels, which the casette gives.
Radio Shack Archer Semiconductor Reference Guide gives good information
how to use that chip. It should be simplest way to go. The chip costs
something like 1-2 $.
--
Tomi.Engdahl@hut.fi  !  LOWERY'S LAW:
then@niksula.hut.fi  !  "If it jams - force it. If it breaks,
                     !   it needed replacing anyway." 
* This text is provided "as is" without any express or implied warranty *

Newsgroup: sci.electronics
document_id: 54187
From: shiekh@ictp.trieste.it (Andy Shiekh)
Subject: 2% silver solder

  I have seen the existance of electronics solder with a 2% silver
content that seems to have good wetting and fatique reatings.
  Can anyone tell me why it is not used? (silver is not such an expensive
metal).


Andy

_____________________________________________________________________
Anwar Y. Shiekh           | I do not feel obliged to believe that the
International Centre for  | same God who has endowed us with sense, 
  Theoretical Physics     | reason, and intellect has intended us to 
Trieste, Italy            | forgo their use.
(shiekh@itsictp.bitnet)   |                        -- Galileo Galilei
_____________________________________________________________________


Newsgroup: sci.electronics
document_id: 54188
From: jaeger.ka.sub.org!stephan (Stephan Jaeger)
Subject: Study as audio control engineer in the U.S.A.

Hi, folks out there !

I don't know whether I am in the right newsgroup, but I have a question.

If I am completely wrong here in this group, could you mail me the right name  
of the correct newsgroup ?

A friend of mine is studying electronics at the Technical University in  
Karlsruhe/Germany since one year.

He wants to know whether there are possibilities to study audio control  
engineering in the U.S.A. .

Does anybody know how to get information about these studies in the U.S.A. ?
Could you send me information like (e-mail)adresses of the universities,  
"quality" of these studies, and so on ?

Is it possible to e-mail the universities directly to get information ?

Do the universities send information via e-mail ?

Please could you answer via e-mail, because I don't read this newsgroup  
regularly.


Thanks in advance.

Stephan Jaeger
-- 
This space for rent.
Contact: Stephan Jaeger, Rheinstr.40, D-7500 Karlsruhe 21
	 +49 721 554293  stephan@jaeger.ka.sub.org

Newsgroup: sci.electronics
document_id: 54189
From: selee@hpcc01.corp.hp.com (Lee Say Eng)
Subject: Re: microstepping

  You can try SGS L6217A, it can achieve 256 current level(microstep),
teere is a circuit in the SGS-THOMSON - " Smart Power Applicatio
Manual", order code for the manual is AMSMARTPOWERST/1

Best regards,

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| Moi,Siew Hong                 | email: shmoi@hpmalr65.mal.hp.com             |
| Hewlett-Packard Malaysia      |                                              |
| Bayan Lepas Free Trade Zone,  | Tel : 604-830-611     Fax : 604-843117       |
| 11900 Penang, Malaysia        |                                              |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Newsgroup: sci.electronics
document_id: 54190
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C
From: MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham)

In <sasrer.735576383@cinnamon> sasrer@unx.sas.com writes:
> services we offered was an engine cleaning (remove all that oil BEFORE you
> sell the car...  ;-}). Unfortunately, we did not have a high pressure
> washer so we would use one several miles from the shop. On more than one
> occasion after washing the engine, it would not start as water would have
> gotten under the distributor (I would put a plastic bag around it to try and
> minimize this), around the spark plug wires, etc and it would be nearly
> IMPOSSIBLE to try and wipe all these areas down with a dry rag. The usual
> solution was to carry a can of WD-40, and when the car wouldn't start to spray
> all the likely areas and it would then start on the very first time.
> 
This definately gets the car going, but... WD-40 is highly flammable. Explosive
even in the right conditions, like a vapour sealed inside a distributor for
eg. And contact points tend to arc a tiny bit :)

I once saw the alternator/points cover blow completely off a motorcycle after
it had been restored to life with WD-40... fun to watch
(It was a Honda MR-50 minibike and the cover is only held on by large rubber 
grommet, so it wasn't really a big blast.)
       Graham B
PS As a more serious aside, it is apparently also conductive, so it is best 
to exercise caution with it around mains wiring.
                                                

Newsgroup: sci.electronics
document_id: 54191
From: speth@cats.ucsc.edu (James Gustave)
Subject: Development tools for 8051?


Could someone point me toward a source (FTP/BBS/whatever) for development
tools for the 8051 microprocessor.  I specifically am looking for a Macintosh
cross-assembler/disassembler.  Also, is there a mailing-list dedicated to
discussing the 8051?  Thanks.

-- 
________________________________________________________________________________
james speth       email for pgp compatible public-key        speth@cats.ucsc.edu

Newsgroup: sci.electronics
document_id: 54192
From: nagle@netcom.com (John Nagle)
Subject: Re: subliminal message flashing on TV

lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick) writes:
>Well, yes and no.  The _image_ can't be on the screen less than 1/30
>of a second, but a _mixture_ of images that's about 90% of the field
>that was supposed to be there and 10% of the 'subliminal' addition
>could be overlaid for one field, producing the same overall effect to
>our sluggish retinae of a discrete image projected for 1/300 second.
   
      This is a 1950s idea.  Supposedly, splicing in a frame of "Buy
popcorn" upped popcorn sales in a movie theatre.  Big flap at the time.
Congress involved.  Talk of making it illegal.  General agreement by
networks not to do it.

      A few years ago, some junior person at an advertising agency
re-invented subliminal projection and one commercial went out on tape
with single-frame messages.  It aired on a few stations, but a tech
at one station, previewing the tape, noticed a flicker and looked at
the tape frame-by-frame to find the "defect".  Big flap.  FCC notified.
Commercial pulled.  Press reports. Embarassed ad agency.  You could
probably find the press reports via Dialog or Nexis if you wanted.

      Now that everybody has VCRs, it's not likely that anybody could
get away with this on TV.

					John Nagle

Newsgroup: sci.electronics
document_id: 54193
From: oscar@oscar.austin.ibm.com (Oscar R. Mitchell)
Subject: Development tools for 65C816?

In article <1ree36INNdmp@darkstar.UCSC.EDU> speth@cats.ucsc.edu (James Gustave) writes:
>
>Could someone point me toward a source (FTP/BBS/whatever) for development
>tools for the 8051 microprocessor.  I specifically am looking for a Macintosh
>cross-assembler/disassembler.  Also, is there a mailing-list dedicated to
>discussing the 8051?  Thanks.
>
>-- 
>________________________________________________________________________________
>james speth       email for pgp compatible public-key        speth@cats.ucsc.edu

I have the same question for any tools for the 6502 derivative processor
the 65C816 processor (designed by Western Design Center).

Thanks,
Oscar.
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Oscar R. Mitchell
  IBM Advanced Workstations and Systems Division
   RISC System/6000(tm) - Future Systems Hardware Architecture and Design Group
   Mail Stop: ZIP 9461
   11400 Burnet Road
   Austin, Texas   78758                               USA Phone: (512)823-0000
   IBM Tieline:  678-8513                              USA "FAX": (512)838-8561

   IBM VNet: OSCAR at AUSVM6
   IBM InterNet: oscar@oscar.austin.ibm.com

     USA InterNet: oscar@austin.ibm.com

#include <standard.disclaimer>   /* I DO NOT speak for IBM, only for MYSELF */
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-- 
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 IBM Corporation - Advanced Workstations and Systems Division
 RISC System/6000(tm) - Future Systems Hardware Architecture and Design Group
                  USA InterNet: oscar@austin.ibm.com

Newsgroup: sci.electronics
document_id: 54194
From: DPierce@world.std.com (Richard D Pierce)
Subject: Re: Pink Noise

In article <34T302tW40N601@JUTS.ccc.amdahl.com> dws30@p1hdb01cd.amdahl.com (David Sharpe) writes:
>
> Pink Noise and White Noise are equal amounts of all frequencies.  This
>is in most cases around the 20-3.3K Hz range.  Pink/White are used to
>adjust for room dynamics and stuff like that.  There are a few EQ's out
>on the market that have Pink noise built in.  Most all from Audio
>Control have them I know the C-101 does.  

Wrong, wrong, completely wrong (and a little misleading, too).

White noise is random noise whose energy density is constant for a
constant bandwidth. That is, a 5 Hz wide band at 20 Hz will have precisely
the same amount of energy as a 5 Hz band at 20 kHz.

Pink noise is random noise whose energy density is constant for a constant
precentage bandwidth. Thus, a 5% wide band of noise at 20 Hz (whose
bandwidth is 1 Hz) will contain the same energy as a 5% wide band at 20
kHz (whose bandwidth is 1000 Hz wide). 

White noise is often used with spectrum analyzers that have constant
bandwidths, pink noise is used with audio-type real-time analyzers whose
bandwidths are centert-frequency dependent (often described as "1/3
octave" or "1/2 octave" or some such terminology).

White noise, relative to pink noise, has more energy at high frequencies
(at a rate equal to 3 dB per octave). Pink noise, relative to white noise,
has more energy at low frequencies (at a rate equl to, again, 3
db/octave).

-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |

Newsgroup: sci.electronics
document_id: 54195
From: hubich@mercury.cs.uregina.ca (Chad D. Hubich)
Subject: Asynchronous Receiver Recommendations?


I am looking for a suitable UART for a project.  What I require 
is a stand alone device (i.e. not cpu controlled) which will 
receive 1200 baud RS232.  Also a nice extra would be a received 
data buffer.  Please reply with any info you have.

Thanks,
--
Chad D. Hubich		University of Regina	Dept. of Computer Science

Newsgroup: sci.electronics
document_id: 54196
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Re: Self-destructing copy protection on VHS tape?

>klp@doe.carleton.ca (Ka Lun Pang) writes:
> 
> Hi folks,
> 
> I borrowed a VHS tape from a friend and it has a warning in the begining sayi
> that attempts to copy the tape will result in destroying the copy and the
> original. I found this unbelievable as playing and recording are two differen
> processes. However, I've never seen this tape being sold anywhere so I don't 
> want to take the chance even it's small.

	Greetings. There are 3 types of warnings on (US) tapes:

	1) A hologram is glued across the seam of the 2 halves of the
	   tape. The message usually reads, "If seal is broken, you must
	   buy this tape"

	2) The standard "MacroVision" warning, "Copies of this tape will
	   be unviewable"

	3) [your case] Extended message for the Average Consumer (tm) which
	   states that even attempting to copy the tape will destroy the
	   original. I don't believe you can sue them for misinformation
	   in cases like this :-)

	Take care.

	P.S. Of course, #3 is utter BS - but the Average Consumer (tm)
	     believes it. Heck, my mom once returned such a tape without
	     watching it... she was afraid that something might just 
	     happen :-)
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
document_id: 54197
From: scottcr@wkuvx1.bitnet
Subject: Re: Cable TVI interference

In article <1993Apr23.191808.10835@rwwa.COM>, witr@rwwa.COM (Robert Withrow) writes:
> In article <1qf44aINNll@rave.larc.nasa.gov>, watson@nimbus.larc.nasa.gov (Catherine Watson) writes:
> 
> | I gave up after a year of
> | letters and phone calls.  I got the impression the FCC was powerless and it 
> | was up to the cable company to correct the situation.
> 
> Isn't there some *formal* action a citizen can take that *requires* the
> FCC to, at least, generate some paperwork?
> 
> -- 
>  Robert Withrow, Tel: +1 617 598 4480, Fax: +1 617 598 4430, Net: witr@rwwa.COM
>  R.W. Withrow Associates, 21 Railroad Ave, Swampscott MA 01907-1821 USA

For those who are interested, the FCC does indeed care about cable
leakage, particularly into the aviation nav band, or leakage that
is "causing interference to other services".

Part 76.611 details specific limits to acceptable leakage, and
measurement technique.  If you will clearly document your problem,
and measurement technique (a signal level meter with dipole is the
normal approach, remember to correct between measurement data and
microvolts per meter) and fax or mail the details to Mr. John Wong
Cable Branch, FCC 1919 M st. NW Wash DC, and a copy of your letter
to the local cable company, you will get results.  In fact the cable
company will probably start treating you much better when they realize
you have figured out how to get the FCCs attention.

What is important is to document your case as it relates to the
applicable rules.  However the cable company *is required* to
at least check out every complaint of leakage.  They must file
with the commission and maintain on premises a yearly measurement
report that details the results of leakage testing.

But remember, call the cable company first, and give them a
chance to work to correct the problem before contacting
the commission.

I am in the business of measuring cable system leakage via
the airborne method.

-- 
SCOTTCR@WKUVX1.BITNET aka Chris Scott- 
                 Telco: (502) 745-3834 

Newsgroup: sci.electronics
document_id: 54198
From: tell@cs.unc.edu (Stephen Tell)
Subject: Re: subliminal message flashing on TV

In article <7480237@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> Hi.  I was doing research on subliminal suggestion for a psychology
>> paper, and I read that one researcher flashed hidden messages on the
>> TV screen at 1/200ths of a second.  Is that possible?

> Might
>even be a vector ("strokewriter") display, in which case the lower limit
>on image time is anyone's guess (and is probably phosphor-persistence limited).

Back in high school I worked as a lab assistant for a bunch of experimental
psychologists at Bell Labs.  When they were doing visual perception and
memory experiments, they used vector-type displays, with 1-millisecond
refresh rates common.

So your case of 1/200th sec is quite practical, and the experimenters were
probably sure that it was 5 milliseconds, not 4 or 6 either.

>Bob Myers  KC0EW >myers@fc.hp.com 

Steve
-- 
Steve Tell       tell@cs.unc.edu H: 919 968 1792  | #5L Estes Park apts
UNC Chapel Hill Computer Science W: 919 962 1845  | Carrboro NC 27510
Engineering is a _lot_ like art:  Some circuits are like lyric poems, some
are like army manuals, and some are like The Hitchhiker's Guide to the Galaxy..

Newsgroup: sci.electronics
document_id: 54199
From: mudayja@wfu.edu (Jeffrey Muday)
Subject: Re: How to the disks copy protected.


This has been an interesting thread to follow... and obviously this group
wasn't intended as a forum for the discussion of piracy... Has anyone seen
any estimates of the lost revenue due to pirates?  I was wondering if
piracy is more rampant in Home or Corporate computing environments.  I would
tend to think that business environment "piracy" is the major contributor to
this form of lost revenue.  So many companies will purchase a few copies of a
software package and then employees will internally distribute them as if they
owned a site-license!  What do you guys think?

Newsgroup: sci.electronics
document_id: 54200
From: jeh@cmkrnl.com
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.

No.  The blue LEDs sold down the street are in milky-white plastic.  

And, fyi, putting a filter on a "typical visible light LED" (presumably meaning
a non-blue one) won't produce blue light.  A filter can only block light, it
can't generate wavelengths that aren't there to start with.  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
document_id: 54201
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: Self-destructing copy protection on VHS tape?

schuch@phx.mcd.mot.com (John Schuch) writes:

>I have always thought that if I wanted to send the Police a tape with
>a ransom demand on it, or send CNN a video tape to see if they wanted
>to buy it, I would place a small magnet near the take-up spool so the
>tape would be erased as it was played. Who would think to check?


That is an exceptionally cool idea.
Would it work?

How strong a field is needed?
Anyone?



Pat@fegmania.wustl.edu  -------------------------------------------------------
  #   #   
   C C    "Revely, Nancy Sinatra, Christmas Carols... a kind of stereo hell" 
  ( " )                                      -- Chris Buery, ABC News
    `
---------------------------------------------------------------- (314)-851-0993

Newsgroup: sci.electronics
document_id: 54202
From: haunma@saturn.wwc.edu (Mark Haun)
Subject: Re: 1-bit A/D converter

In article <1993Apr24.201422.25682@oucsace.cs.ohiou.edu> mcorbin@oucsace.cs.ohiou.edu (Max Corbin) writes:
>Once upon a time, long long ago in this news group, someone
>posted a schematic for a 1-bit A/D converter.  Well I just found a use
>for the little monster.  Anyone out there still got this text file?
>It had a flip-flop, a resistor and a cap, and a comparator/op-amp I 
>think.  I would be extremely thankful to anyone who could mail me the 
>schematic or post it to the news-group.

Hmmm... how about a piece of copper wire?  0 to 5V input range, standard
TTL output, instantaneous conversion time!

[ (-:  for the humor impaired ]


     Mark A. Haun       | INTERNET: haunma@wwc.edu
   252 Sittner Hall     | Amateur Radio KJ6PC
College Place, WA 99324 |
   +1 509 527 2297      |

Newsgroup: sci.electronics
document_id: 54203
From: schmidt@auvax1.adelphi.edu
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

In article <1993Apr25.094202.3978@lugb.latrobe.edu.au>, MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham) writes:
> In <sasrer.735576383@cinnamon> sasrer@unx.sas.com writes:
>> services we offered was an engine cleaning (remove all that oil BEFORE you
>> sell the car...  ;-}). Unfortunately, we did not have a high pressure
.........
>> 
> This definately gets the car going, but... WD-40 is highly flammable. Explosive
> even in the right conditions, like a vapour sealed inside a distributor for
> eg. And contact points tend to arc a tiny bit :)
> 
> I once saw the alternator/points cover blow completely off a motorcycle after
> it had been restored to life with WD-40... fun to watch
> (It was a Honda MR-50 minibike and the cover is only held on by large rubber 
> grommet, so it wasn't really a big blast.)
>        Graham B
> PS As a more serious aside, it is apparently also conductive, so it is best 
> to exercise caution with it around mains wiring.
>                                                 
I, some years ago, almost became a victim of this.  Squirted a fair amount in
an old model 15 Teletype which was acting up, then turned it on.  The eruption
when the motor starting contacts broke was mighty spectacular... I almost got
my eyebrows singed, the plastic (old ones had safety glass) cover over the
platen, etc flew across the room, and several people in the room almost had
heart attacks.  Beware the explosive properties of WD40 vapor.

-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218
Adelphi University                 |       Evenings (516)877-6400
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
document_id: 54204
From: schmidt@auvax1.adelphi.edu
Subject: Re: subliminal message flashing on TV

In article <nagleC6213E.DsE@netcom.com>, nagle@netcom.com (John Nagle) writes:
> lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick) writes:
>>Well, yes and no.  The _image_ can't be on the screen less than 1/30
>>of a second, but a _mixture_ of images that's about 90% of the field
>>that was supposed to be there and 10% of the 'subliminal' addition
>>could be overlaid for one field, producing the same overall effect to
>>our sluggish retinae of a discrete image projected for 1/300 second.
>    
>       This is a 1950s idea.  Supposedly, splicing in a frame of "Buy
> popcorn" upped popcorn sales in a movie theatre.  Big flap at the time.
> Congress involved.  Talk of making it illegal.  General agreement by
> networks not to do it.

More than Talk:  From the FCC Rules:  73.4250 Subliminal Perception:

(a) See Public Notice, FCC 74-78, dated January 24, 1974, 44 FCC 2d, 1016; 39
Fr 3714, January 29, 1974.
(b) See FCC Information Bulletin, "Subliminal Projection" (sic, at least in my
rules service copy of the rules), dated November 1977.

Since I don't have either old copies of the Federal Register or the Information
Bulletin around, I can't tell you what you can't do on TV ( or radio) but I
seem to remember this being an unnecisarily hot subject in the late '70s. 

Practically speaking, I dont have too much trouble seeing the one frame edits
in MTV promos,  badly scratched or torn single frames in films and such, but
maby that's just because the contrast between the single frame and the
surrounding material was significant.  I never believed in the one-frame type
of SP being real.  

On the other hand, the Coca-Cola or Brand (insert desired name here) beer cans
conveniently placed so the brand name is visible in the movie you just watched,
that's another story, and if your TV station or network was paid by the beer
company for the privilege of doing that, there has to be a "Promotional
Consideration paid by ...) or similar message included with the program; but if
the TV station bought the movie already edited that way from the film company
and didn't get any of the payment for "brand visibility" that the film company
got, then they don't have to run the message.
> 
>       A few years ago, some junior person at an advertising agency
> re-invented subliminal projection and one commercial went out on tape
> with single-frame messages.  It aired on a few stations, but a tech
> at one station, previewing the tape, noticed a flicker and looked at
> the tape frame-by-frame to find the "defect".  Big flap.  FCC notified.
> Commercial pulled.  Press reports. Embarassed ad agency.  You could
> probably find the press reports via Dialog or Nexis if you wanted.
> 
>       Now that everybody has VCRs, it's not likely that anybody could
> get away with this on TV.
> 
> 					John Nagle
-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218
Adelphi University                 |       Evenings (516)877-6400
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
document_id: 54205
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: 77P20 programmer

Having vainly looked for devices capable of dealing to the NEC 77P20
DSP chip which dont require taking out a mortgage, i decided to roll
my own. Not a difficult task for an 8751, given that all the timing
relationships are set out in the databook. One thing bothers me, that
is the accursed 50ms 21 volt Vpp pulse. Sure, a little buck step-up
converter can achieve this (in what is otherwise an all 5 volt widget)
but i know latterday eproms dont need nearly this pulse length.
Q : has anyone come up with a more efficient programming algorithm
which is failsafe ?
cheers
Mike.

Newsgroup: sci.electronics
document_id: 54206
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

wb8foz@skybridge.SCL.CWRU.Edu (David Lesher) writes:
: 
: (Why do ALL  postings from bnr seem to have bogus addresses? 
: Both 
: 	gstovall@crchh67.NoSubdomain.NoDomain
: and 
: 	gstovall@bnr.com
: bounce....
: 
: This makes it rather difficult to reply....)

They go through UUNET. This is often the problem - as UUNET often has
problems with return paths.

... deleted ...

: Oh, and most importantly, no amount of transmitted RF, short of a
: transmitter the size of small house, is likely to cause the equipment
: failures you describe. So you are looking at two different problems.

Yep.

Bill

Newsgroup: sci.electronics
document_id: 54207
From: Sean_Oliver@mindlink.bc.ca (Sean Oliver)
Subject: descrambling channels

I live up in British Columbia, Canada.The cable company I use is called
Rogers Cable. Does anyone know of their scrambling techniques, and ways of
getting
around them? Any suggestions of what they might use?

--
+--------------------------------------------+
| Sean Oliver                                |
| Internet Address: a8647@MINDLINK.BC.CA     |
|                                            |
| Mindlink! BBS (604)576-1412                |
+--------------------------------------------+


Newsgroup: sci.electronics
document_id: 54208
From: shorty@nevada.edu (DAVID HAAG)
Subject: Re: Pink Noise

In article <34T302tW40N601@JUTS.ccc.amdahl.com> dws30@p1hdb01cd.amdahl.com (David Sharpe) writes:
>
> Pink Noise and White Noise are equal amounts of all frequencies.  This
>is in most cases around the 20-3.3K Hz range.  Pink/White are used to
>adjust for room dynamics and stuff like that.  There are a few EQ's out
>on the market that have Pink noise built in.  Most all from Audio
>Control have them I know the C-101 does.  
 

With regards to what you wrote, how does one "adjust for room dynamics 
and stuff like that"?  I asked a professor that question just
last week and he didn't really know himself.  Since pink noise is believed
to be due to surface states (say, the surface of the Silicon where there's
a lack of a covalent bond) that act as "traps" to nearby elecrons, and since
this happens at low frequencies (because at high frequencies they aren't
able to "trap" electrons), how do you compensate for that?  It seems to me
that you wouldn't be able to compensate for pink noise.  I have seen the
"pink noise" feature, however, on many EQs, and I was wondering
how they are suppose to compensate for noise when pink noise is not due to
"man made noise" like power lines, crosstalks, coupling, etc.  If you have
any information about this, it would be appreciated.  Hope this didn't sound
too drawn out.  Thanx.
 
                              - David (shorty@helios.nevada.edu)








Newsgroup: sci.electronics
document_id: 54209
From: irsman@iastate.edu (Ian Schmidt)
Subject: Re: Development tools for 65C816?

In article <C6217x.2xoL@austin.ibm.com> oscar@oscar.austin.ibm.com (Oscar R. Mitchell) writes:

[request for WDC65c816 Mac cross-development stuff]

Apple themselves sells a 65816 cross-developer for the Macintosh called 
'MPW IIgs' (it's intended for use with the Apple IIgs computer, which uses
the '816).

> Oscar R. Mitchell

-- 
        Ian Schmidt - Two Meg Software: irsman@{iastate.edu | aol.com}
"I will choose a path that's     | Author of AudioZap, MODZap, and more.
 clear: I will choose free will" | Co-author of SoundConvert and DeskTracker.
 - N. Peart, 1980                | Coder and Musician for the GS<>IRC.

Newsgroup: sci.electronics
document_id: 54210
From: fuchs@tsar.princeton.edu (Ira H. Fuchs)
Subject: Removing battery corrosion

Is there a readily available solvent that does a good job at removing the  
corrosion/encrustation that collects on the battery terminals (usually the  
cathode) when using alkaline batteries (or more accurately, when NOT using  
them for a long time)? 

Newsgroup: sci.electronics
document_id: 54211
From: jsm@shade.Princeton.EDU (John Scott McCauley Jr.)
Subject: how to get rid of flyback whine?

I recently took apart my color Sony TV to clean the volume pushbuttons and
when I put the beast back together, the flyback whine got much louder.

Is this easy to fix? Which part is resonating? I have heard rumors of a
spray that will fix the noise.  Is this a simple thing for a TV repairman
to fix?

	Thanks,

		Scott

Newsgroup: sci.electronics
document_id: 54212
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: ATARI 2600 Processors

In article <1r7e14$l2c@sunb.ocs.mq.edu.au> ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:
>In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>>game machine). 
>
>Wrong, it has a 6507.

Sorry Ian, I haven't toyed with it in several years. I haven't seen
the insides in quite a few years. I just saw the post lagging for
quite a few days, and thought I'd toss in my $0.02. I assume the 6507
was functionally similar to the 6502 (was it also made by MOS
Technologies?). I really am more versed in the (6502 based) Atari
computers. The 2600 came later on.

>
>>The 2600 had some extra ASIC chips that were basically
>>modified graphics chips and PIA's for the joysticks. 
>
>It had one custome chip (not an ASIC in the sense that word is now understood):
>the TIA (sometimes known as the 6526, although most other manufacturers list
>that as the CIA complex interface adapter.)  TIA stands for Television
>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>the 2600 possessed.

In the Atari computers, the "CIA" chip you refer to sounds an awful
lot like the CTIA (Color Television Interface Adapter) chip used in
the early models. Later Atari upgraded this to the GTIA (Graphics
...). Other colorful literature stated that the GTIA might have stood
for "George," the developer of the chip.

>
>There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
>regulator and (if memory serves) a 555 timer.  That's all.
>
>>Later model 2600
>>might have incorporated many of the chips into one ASCI, as the weight
>>of the machines and part count decreased a lot over the years.
>
>Not according to the servicing documentation I have here.  The 2600 did not
>change intenally very much at all.

Funny, I had an old and new model. The old one was SIGNIFICANTLY heavier.

>>Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
>>their games. 
>
>ROMS were mapped into the upper 4K of the 6507's address space.  2K and 4K
>games were fine, but later 8K and 16K games needed bank switching.  Atari
>(and others) made much of these "huge" cartridges.
>
>>I have no idea how much RAM it had to work with, but I
>>would hazard a guess of 2 or 4K RAM. 

Sorry, I am way out of line here. My first microcontroller I built was
a MC68701 based chipset with 128 bytes onboard. That was not easy to
work with (in addtion to a small 2K on-board EPROM).

>Wrong, it had 128 bytes of RAM from the RIOT.  This was multiply mapped into
>both page 0 (pseudo-registers) and page 1 (stack), and also throughout the
>bottom 4K of memory.  TIA registers also sat in this address space.
>
>As 128 bytes of RAM was somewhat limiting, some later cartridges also carried
>RAM themselves, which was interesting as Atari had provided no write line
>to the cart.  This was managed by mapping the reads from RAM into one address
>range, and the writes into another, but all the time this scheme ate into
>the *very* scarce ROM address space.
>
>							Ian.



Newsgroup: sci.electronics
document_id: 54213
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <C60DvH.FAn@ucdavis.edu> ez019654@othello.ucdavis.edu (Victoria Milliron) writes:
>From: ez019654@othello.ucdavis.edu (Victoria Milliron)
>Subject: Re: How to the disks copy protected.
>Date: Sat, 24 Apr 1993 22:16:29 GMT
>Hmmm...
>What is the problem with parallel port security keys? I haven't used anything
>that had hardware key copy protection schemes, so I don't know what the
>drawbacks are. I know the companies that make them claim they're uncrackable,
>but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
>so don't ask) and I had heard that it had parralel port keys.

If you put another computer on the port instead of the key, you can hack 
them by reading what happens. So I've been told, I've never seen this done 
but I think it's possible. You'd need some hardware knowledge and some 
software to read the port!


>
>vamilliron@othello.ucd.edu
>-my apologies if I rambled, but vi inhibits my communication skills greatly.

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only once.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54214
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

dplatt@ntg.com (Dave Platt) writes:
: 
: >What kind of power must he be putting out to cause the effects?
: >The affected equipment is about 100 feet from the road...
: 
: Might be a couple of hundred watts, from the sound of it.  Kicking sound
: out of the TV and stereo speakers by direct RF rectification requires a
: mighty strong carrier!  [I've heard of linears so powerful that
: triggering them while the car was idling, would stall the engine by
: pulling down the battery voltage.]

It would take a lot more than that. It sounds like the radio equipment is
actually not shut completely off - but just goes to a standby situation.

I suspect that the stories are just that, stories.  The voltage can only
be sucked down so far instantaneously. When you try to jumpstart someones 
car, when your vehicle is at idle, does your car stall? No, the other car
just does not crank well.  Now, the engine might stall because the idle
was too low to start with. When the extra current is drawn, the idle speed
will drop - as the alternator loads down the engine to compensate for the
increased amperage requirement.

: >Is resolution of this problem a matter for the power company, the fcc, or both?
: 
: Ultimately it's likely to be your problem to resolve, I'm afraid.  The
: FCC is so understaffed that they don't pay much attention to citizen
: complains about RFI (or so I've heard)... they'll just send you a
: pamphlet describing how you can apply corrective measures.
: 
: Talking to the power company might help - they might be able to install
: filtering devices at your service panel (or recommend a type which you
: could have installed by a licensed electrician).

A transmitter is not going to be affecting house power. If surges are
occurring there, it is due to another cause - not a transmitter.

: Unfortunately, there's a fair chance that enough signal is being picked
: up by your house wiring that a simple service-panel filter won't
: suffice.  You may need to install heavy-duty RFI filters at the power
: connections of your affected equipment.

It is probably not that much of a problem. Often - toroid coils on the
power leads will solve that part of the interference problem. It will
not solve internal equipment deficiencies.

: If the problem occurs regularly, you may need to "stake out" the street
: in question, and watch for trucks or cars with big antennae driving by
: at the time interference occurs.  If you can identify the vehicle which
: is transmitting, you may be able to contact its owner and complain.

It is probably not the transmitter that is at fault. If the person is an
amateur, then he/she will probably be willing to help - if you explain
that the person is causing interference.

Bill

Newsgroup: sci.electronics
document_id: 54215
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

drand@spinner.osf.org (Douglas S. Rand) writes:
: 
:    Hams can legally run up to 1500 watts.  It is very unlikely, however,
:    that a ham would be running that kind of power from a car.  Ham rigs
: 
: Not possible either.  You'd need about a 300 amp alternator for
: just the amplifier.  I can just see it.  You need to slow
: down on a downgrade,  so you hit the push to talk button.

Well - 100+ amps anyway. Transmissions are generally for a short interval.
The battery would supply the rest. Of course, if you transmitted too much,
you would run the battery down.

It really would not be that much of a brake.  Even at 50% efficiency, 1500
watts would only consume 4 horsepower.

Bill

Newsgroup: sci.electronics
document_id: 54216
From: hugo@cats.ucsc.edu (Hugo Calendar)
Subject: How universal are phones these days?


I'm wondering if I can tote my American touch tone phone around with me
to Sweden and Germany.  It's DC powered, and I can buy a special adapter
for that in Europe.  The question is if the general electronics work
the same.  I can buy a different wall plug and refit it (I'm sure I'd
have to), but would that do the trick?

Thanks,
Hugo

Newsgroup: sci.electronics
document_id: 54217
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

brian@ucsd.edu (Brian Kantor) writes:
: While it's possible that it's a ham radio transmitter that you're
: hearing, it isn't likely - every bit of signal that doesn't go out the
: antenna is wasted, as far as a ham is concerned, and most hams are

It is the radiated signal that would cause the problem.

: technically competent to ensure that they don't waste any signal if they
: can possibly avoid it.  To get their ham license, they had to pass a
: government exam that tests them on that point, among others.
: 
: However, you could be hearing a radio transmitter for sure - there are
: lots of other services where the operators AREN'T required to be
: technically competent - Citizens Band ("CB"), for example.

There is nothing in the Amateur Radio Tests that requires an technical
competence at all. It is a simple matter to memorize all the questions
and answers.  However, that said, most Hams that I know do spend quite
a bit of time gaining some technical skill.

: Listen to the interference.  If you hear voices clearly, it almost
: certainly ISN'T ham radio, and might well be CB.  If you can record a

Don't count on that.

: bit of it, you could take the tape over to a local ham operator's house
: and ask him for his opinion of what you're hearing.  Most communities

You cannot do that legally. However, you can ask a ham over to listen.
If the interference occurs at a specific time each day, then it would
be possible to do such scheduling.  If nothing else, you could invite
the ham over to transmit from your driveway, to see if he interferes.
If he does, then you probably need to have your equipment worked on to
make it immune to rf interference.

: have a ham radio interference committee whose members are most willing
: to help you resolve interference complaints.  Look in the phone book, or
: ask at the local ham radio store, or call the FCC for contact info.

The FCC may, or may not, have such information. They have enough to do
without getting calls for such information. If nothing else, call your
city offices or police department (general business number). They should
have the name of a local ham contact.

: If it's a ham, he's more than likely willing to help get rid of the
: problem.  After all, it would be his signal he's wasting.  If it isn't,
: the interference committee or the FCC may be able to suggest solutions.

See above - your concept of wasted signal is erroneous. If his rig is
transmitting properly, then the chance of interference (with the exception
of harmonic television interference) is the greatest - since he is putting
out the strongest signal.

: It is unfortunately the case that a transmitting station that is
: operating perfectly legally could possibly cause intereference to a
: piece of consumer audio or TV equipment just because the manufacturer of
: the consumer equipment cut corners on one little section of the device
: that wouldn't affect one person in a thousand, but which bites you.
: Often that can be remedied for just a few pennies by a knowledgeable
: person, perhaps even the person operating the transmitter you're
: hearing.

Unfortunately, most consumer equipment is succeptable - it is all poorly
designed.

: (BTW: hams are ALLOWED amplifiers; CB isn't.  "illegal ham amplifier"
: doesn't compute.)

It does, but not for a mobile radio. There are very few mobile rigs that
could power a 1500 watt amplifier.

Bill

Newsgroup: sci.electronics
document_id: 54218
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: Laser vs Bubblejet?

	Just thought I would add $0.02 to DeskJet thread. I got my
first one in college about 5 or so years ago.

	I've been a happy HP user of the DeskWriter for Macintosh for
past 5 years. I got one just a few months after their release. And I
got software revision 1.0a (now I'm up to rev. 3.1. Our family (sister
and father) have each purchased their own DW's after seeing mine go
for one year unscathed (their stuck to their trusty ImageWriter II's).
The original DW has gone for 5 years at moderate personal use. I would
say that it has gone through at least 15,000 sheets, and around one
(small) ink cartridge every 3 months or so.

	My brother might take this DW now (I'm probably gonna give it
to him), and I am looking to upgrade to a color DW. The chief
advantages/disadvantages I've found over the years are:

Advantages:	Quick (2-3 ppm), Quiet (roomate can sleep while it's
printing), AppleTalk Networkable (unfortunately the original wasn't,
so look out if you buy used. I rewired our home with phonenet
AppleTalk connectors, and while home, we can all use my dad's one
DW!), and cheap (now run ~$300). BTW, you can upgrade older DW's to
color or for appletalk, I dunno if HP still does the upgrades, but I
received many offers (I just didn't ned it however). Also, crisp
laser-quality output is a wonder (used to really impress those
ImageWriter Dot-Matrix people so much so, that I had to charge $0.25
per sheet to stop my college dorm neighbors from bothering me at all
hours of the night....)

Disadvantages.	Ink used to be hard to find, and wasn't cheap, and
wasn't originally water-proof. While HP has done wonders with the ink
(I dunno if it's still toxic), it is still subjet to smearing and
running (if you run around in the damp Boston rain, and get your
bookbag completely soaked). Ink now runs about $14-$15 for small carts
(I get mine from Elek-Tek in Chicago, I think they're now down to
$12). The ink carts used to say they're dated for only 6 months, but
I don't think they say so anymore. We stick to a 4 month supply (of
about 3 carts). We use cheap Hammerhill Laser Print paper (after
fooling for a long time. Laser/Xerox paper is also good). Smearing
doesn't happen, unless you have a brand new ink cart and you grab the
paper and smudge it all over as soon as it comes out of the machine.
Other disadvantages are : No Postscript (this can be an advantage in
speed, usually). Ways around this are Ghostscript or Freedom of Press
software solutions. I bet HP probably has a PS prototype inkjet, but
they won't release it for fear of hurting LJ sales.

In the end, the primary advantages of laser are true postscript
(unless you go for cheap lasers), and fused toner (no smearing, even
when soaking in water). Lasers are slightly sharper, but the only
instance where I needed precise layouts was Printed Circuit Board
Transparencies for PhotoEtching. I found a Textronix color Phaser
Postscript (Thermal Wax Transfer) to work the best to make PCB
negatives directly onto a transparency.

Well, hope my babbling has helped.
-squish@endor.harvard.edu


Newsgroup: sci.electronics
document_id: 54219
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: How to the disks copy protected.

In article <rcstage1.132.735807672@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:

[stuff about hardware keys]

>If you put another computer on the port instead of the key, you can hack 
>them by reading what happens. So I've been told, I've never seen this done 
>but I think it's possible. You'd need some hardware knowledge and some 
>software to read the port!

True, which is why many of the newer keys ship out, oh, maybe 32 bits or
so, have the key encrypt them, and return them to the PC.  Making a bunch
of these 32 bits part of your program code is a good way to make sure
things won't run without the key. :-)  Anyway, then, this scheme at least
defeats your approach.  It's a little costly, though.

Personally, I don't believe in copy protection, and agree with the thought
that the mass inconvenience that it causes all legal users far outweighs
the gains from what few pirates won't be able to copy the program.

					---Joel Kolstad


Newsgroup: sci.electronics
document_id: 54220
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: help with phone wire: which ones are "tip" & "ring"?

In article <1993Apr22.103922.23177@husc3.harvard.edu> mlevin@husc8.harvard.edu (Michael Levin) writes:
>
>I just bought a little gizmo that is supposed to be installed "in
>series with the tip or ring lines" of the phone wire. Which ones are
>those? Suppose I am holding a regular phone wire, such that the little
>plastic tooth (on the little plastic square thing with the naked lead
>ends that you plug into the phone) is facing down, and away from me.
>Which of the 4 wires that I see is the "tip" and which is the "ring"?
>Please reply to mlevin@husc8.harvard.edu.
>
>Mike Levin
>
Mike, Ring is the RED wire. Tip is the GREEN wire of most standard
phone lines. They two constitute the two wires most often used for
voice telephone (the two live lines). They are the two innermost
connectors of an RJ-11 phone jack.

Another way of telling is that if you measure voltage from RED to
GREEN (ring to tip. tip/green being at ground potential of the
voltmeter), it should read -48 volts in the on-hook no-ring position).
I am 98% sure it's -48 V and not +48 volts. Doesn't hurt a phone too
much if they're reversed, it's just bad if one happens to somehow get
grounded to earth ground elsewhere).

Additionally, when off-hook, the voltage drops to about -4 to -9 Volts
DC. I think it is supposed to correspond to a 36 to 40 mA current
loop. And lastly, when ringing, the two wires develop an AC potential
of about 80 V p-p at 20 to 30 Hz across them (where you get the
electromechanical old fashioned bell ringer from).

Hope that clears things...
-squish@endor.harvard.edu




Newsgroup: sci.electronics
document_id: 54221
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: blinking LEDs?

In article <199304241801.AA26885@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:
>
>
>   Where can I buy blinking LEDs besides radio shack? 
>
>
>  * Does anyone sell blinking LEDs with variable flash rate? (by voltage
>    I guess) If so, what hertz (pulse) rate are they adjustable or set to?
>
>     I'd like blinking LEDs that can be set for approx 5 hz, 10 hz, 
>     15 hz, or 20 hz. Something like that... I'm interested in what's
>     out there for flash rates. I like the idea of LEDs with flasher 
>     circuits already in them. I hate soldering ICs in general. Guess I
>     don't have a hell of a lot of patience. 
>
>
>      Thanks,
>
>         Dana
>
If you want slow LED flash rates, adjustable by switches (or by a
4066/4016 digitally controlled switch), I suggest looking at a 555
oscillator chip. They cost ~$1 at Radio Shack (much cheaper in
quantity at quality places), and you will be able to find good info
about simple circuits in a 555 oscialltor notebook (I think Forest
Mims has one at Radio Shack). You'll have to toy with
resistor/capacitor values OR you can use your head with a little math
to get the right frequencies. Any engineer worth his salt, can make a
555 osciallator... It's in the book, and left up to you to see (I hate
doing ASCII circuit graphics). The 555 can accurately go from a few Hz
to about 500 KHz (I think).

About the Tape Recorder gizmo, you could alter a stereo tape deck to
use one channel as a DATA line (for flashing LED), and one as audio
line (for voice or music). This would eliminate a lot of noise.

The data line is probably most easily done
by some kind of PLL or bandpass filter (using just an op-amp). The 565
chip is a good PLL, and not hard to work with. However if you nothing
about how a PLL works, I suggest you don't try this. Op-Amp
information can also be found in the Forest Mims Radio Shack
info-booklets, and the popular 741 op-amp is a snap to work with.
Setting frequency and bandpass filter values are not so easy, so I
would suggest the 555 method firstmost... I have no idea what this is
going into, so I am really generalizing...

As for manufacturing techniques, if you're only goofing with it, I
suggest you breadboard the thing... No need to solder. Wire-wrap would
be the next, more permanent step. And lastly, soldering/PCB making.
Hope that clears things......

-squish@endor.harvard.edu


Newsgroup: sci.electronics
document_id: 54222
Subject: Re: what to do with old 256k SIMMs?
From: cvafymfa@vmsb.is.csupomona.edu (Srikanth Viswanathan)

In article <1qkf2hINN65c@rave.larc.nasa.gov>, kludge@grissom.larc.nasa.gov (Scott Dorsey) writes...
>In article <C5JCH1.FrC@ulowell.ulowell.edu> wex@cs.ulowell.edu writes:
>>In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
>>|> >	I was wondering if people had any good uses for old
>>|> >256k SIMMs.  I have a bunch of them for the Apple Mac
>>|> >and I know lots of other people do to.  I have tried to
>>|> >sell them but have gotten NO interest.
>>

Well,  if you're willing to spend a little money,  you could buy one
of those IDE caching controllers (assuming you have an IDE of course)
and put the 256K SIMMs on them.  Hardware cache!

Srikanth

Newsgroup: sci.electronics
document_id: 54223
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: Lead ACid Batteries Part 2!!!

In article <1993Apr25.013013.13717@cronkite.ocis.temple.edu>, camter28@astro.ocis.temple.edu (Carter Ames) writes:
> 
>    I thought the first thread was hilarious, so here goes another post.
> 
> Some more background information on what has happened to my poor batteries.
> 
>   One year, I left the batteries in the garage.  The garage is Unheated.  
> They were left in their places that they needed to be.  One in the riding
> lawnmower (what a lux) and one in each motorcycle.  The battery in the 
> riding lawnmower was about 3-4 years old, and one of the cycle batteries 
> was new, and one was around 5 years old.  Upon spring time, I discovered
> that all of the batteries were dead, and needed to be recharged.  They all
> worked properly, except for the older ones, and they had to be replaced 
> about halfway through the summer.  (they had originally been stored
> in the garage, and I think I remember my dad charging them in spring)
>   Last year, I decided to bring them in to the basement, which has two parts.
> one is dirt and brick, and the other is concrete.  I brought in all three, and
> discovered in the spring, (about 15 days ago) that not only were the batteries
> dead, but when I put the charger on them, the charger said "HMMMMMMMM" and 
> the amp-meter read around 1,000,000,000  (In other words, it was pinned)
> the internal circut tripped, and I went on to the other batteries.  They
> were the same.  
>    Realizing that we still had 2 GIGANTIC sailboat batteries, also lead
> acid, I decided to put the charger on them.  (these had been sitting for around 1 and a half years, on the brick and dirt part) and noticed that they only
> needed a small charge, around 2 hours or so on trickle.  I tested them
> by using them at the local gas station for giving jump starts, and they
> worked fine for around 25 of 'em. 
>   This leads me to believe one of several things.
>      1) I bought really #$%tty batteries last year. (sorta true)
>      2) the concrete has something to do with the discharge of the
>         batteries.
>      3) There was enough moisture to short out the terminals in the 
>           room where the concrete is, 
>      4) The dirt room was able to absorb the moisture in the air
>          better than concrete.
> 
> (BTW, I can almost waterski in the dirt room)  
> 
>    Any other ideas?
>     *could be the aliens, anything is possible.*
>  
 
The lead-acid secondary cell releases energy (electricity) with the following
chemical reaction:
 
Pb + PbO2 + 2H2SO4 --> 2PbSO4 + 2H20
 
Lead and Lead (IV) Oxide and Sulfuric Acid produce Lead Sulfate and Water
 
The standard heats of formation at 25 C (77 F) of the various compounds are:
 
              Heat of formation
Compound      at 25 C, kcal/mole
--------      ------------------
   Pb               0.00
  PbO2            -65.0
 H2SO4           -193.69
 PbSO4           -218.5
  H20             -68.3174
 
The heat of reaction at 25 C is therefore -60.6 kcal per mole PbSO4 produced.
Note that lead sulfate is not very soluble (0.0048 grams per 100 grams water
at 25 C), and it will thus precipitate out of solution where the reaction is
occurring, or the cathode (positive terminal) of the battery.  (I am almost
sure it is the positive terminal where the precipitate forms, but I may be
wrong.  Oh well, I don't have a corroded battery to corrobate, and I don't feel
like thinking through it right now.)
 
What is important to notice here is that the reaction, as you knew it would be,
is exothermic, or energy discharging.  If moisture with dissolved electrolytes
(acid rain) condenses on the battery, a conductive path between the terminals
may form.  This will discharge the battery as the chemical reaction proceeds.
The reaction is reversible, if electricity (from an alternator or battery
charger) is put back into the battery.
 
Lead-acid batteries must change in chemical composition to discharge.  Each
cell has all the reactants necessary for the reaction.  The non-reacting posts
(terminals) of the lead-acid battery are there to remove (or add) electric
energy during a discharge (or charge).  Because the reaction is exothermic, it
has a tendency to happen, though quite slowly under normal circumstances.  So
while keeping the battery dry is a good idea, it is not a total solution.
 
To understand why lead-acid batteries DO INDEED discharge faster when stored on
concrete as opposed to wood or earth (dirt), one should recall LeChatelier's
Principle, which can be paraphrased as:  anything subjected to some stress will
act to move to a more comfortable position.  Here are the thermal conductivities
of a some selected materials:
 
                                              thermal conductivity
       material           Temperature, C (F)  BTU/(hr-ft-ft)(F/ft)
       --------           ------------------  --------------------
diatomaceous earth,            204                   0.051
 natural, across strata        871                   0.077
diatomaceous, natural,         204                   0.081
 parallel to strata            871                   0.106
diatomaceous earth powder     (100)                  0.039
  (density, 18 lb/cu.ft)      (200)                  0.042
                              (300)                  0.044
                              (400)                  0.048
                              (500)                  0.051
concrete (cinder)              ---                   0.20
         (stone)               ---                   0.54
         (1:4 dry)             ---                   0.44
pine (across grain)             15                   0.087
   (parallel to grain)          21                   0.20
oak (across grain)              15                   0.12
maple (across grain)            50                   0.11
 
Note that the thermal conductivity for "dirt" (diatomaceous earth) goes down
with temperature.  Also, 204 C is about 400 K, and the values for earth powder
are on the same order of magnitude as natural earth.  The thermal conductivity
of concrete is around a factor of 10 greater than that of dirt, and is 2-4
times greater than wood.
 
It is these differences in thermal conductivity that cause the battery on
concrete to discharge faster than that on dirt or wood.  At any instant the
discharge reaction is occurring, energy is being released, either as electricity
or heat.  (Thermal conductivity of air is about 0.015 BTU/(hr-ft-ft)(F/ft).)
During storage, except for the trickle that passes through any condensate on
the battery, this energy is mostly released as heat.  The higher conductivity
surface will remove the heat proportionately faster than the lower conductivity
surface.  Thus, if you perfectly insulated a dry battery on all but the bottom
surface, at any given battery temperature above the storage surface temperature,
the battery on a concrete surface will be discharging about 10 times faster
than that on dirt.
 
This is where LeChatelier's principle comes into play.  Removing energy from
the exothermic reaction will drive the reaction further to completion.  If the
reaction normally occurs at room temperature, keeping the battery at that
temperature requires the removal of any heat produced.  A concrete surface is
a better heat sink than a dirt or wood surface.  Store a battery in the corner
of a poured concrete basement, and you have 3 surfaces removing energy, which
"pulls" the reaction along.
 
Also, if water evaporates from the battery, that elevates the ratio of sulfuric
acid to water.  This will tend to drive the discharge reaction.
 
Jeff White      jhwhit01@ulkyvx.louisville.edu
 
"How do I get the ketchup out of my pocket protector?"  French fries!

Newsgroup: sci.electronics
document_id: 54224
From: wd@cs.tu-berlin.de (Wolfgang Diestelkamp)
Subject: Re: How universal are phones these days?

In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

> I'm wondering if I can tote my American touch tone phone around with me
> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
> for that in Europe.  The question is if the general electronics work
> the same.  I can buy a different wall plug and refit it (I'm sure I'd
> have to), but would that do the trick?

Two things to watch for:
In Germany (and I think the same holds for Sweden) only some
of the connections can handle tone dialing, so make sure the
phone can be set to pulse dialing.
In Sweden, the '0' is the first digit and all other digits
are pushed "down" by one position; this makes dialing (and
in the process converting numbers) an interesting task.
Otherwise, it is technically no problem to connect a foreign
phone to either the German or Swedish phone system.
OTOH neither you nor I would ever try that, as it is of course
illegal.
-- 
Wolfgang Diestelkamp
wd@cs.tu-berlin.de
wolfgang@first.gmd.de


Newsgroup: sci.electronics
document_id: 54225
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: 600RPM Floopy drives - UPDATE!

In article <C5wIEE.Gn3@ms.uky.edu> msunde01@mik.uky.edu writes:

>> Hopefully this should sort it all out .... not bad for 9 quid (normally
>                                                         ^^^^^^
>Pardon my ignorance of foreign currency and exchange rates, but what is a  
>quid, how does it relate to the British Pound (or whatever it's called)  
>and what is that in American Dollars??? :-)
k
Sorry ... should have used correct terminology

1 Quid = 1 Knicker = 1.54 approx U.S. Dollars 

The Terry Pratchett Book "Good Omens" contains an adequate explanation
of the rather strange UK money system, past and present for "Americans, 
Tibetans, and other alien species" :-)

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================


Newsgroup: sci.electronics
document_id: 54226
From: lhe@sics.se (Lars-Henrik Eriksson)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:
   In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

   > I'm wondering if I can tote my American touch tone phone around with me
   > to Sweden and Germany.  It's DC powered, and I can buy a special adapter
   > for that in Europe.  The question is if the general electronics work
   > the same.  I can buy a different wall plug and refit it (I'm sure I'd
   > have to), but would that do the trick?

   Two things to watch for:
   In Germany (and I think the same holds for Sweden) only some
   of the connections can handle tone dialing, so make sure the
   phone can be set to pulse dialing.

Most (if not virtually all) swedish exchanges can handle tone
dialling. Many older electromechanical exchanges have been modified
accept tone dialling.
--
Lars-Henrik Eriksson                            Internet: lhe@sics.se
Swedish Institute of Computer Science           Phone (intn'l): +46 8 752 15 09
Box 1263                                        Telefon (nat'l): 08 - 752 15 09
S-164 28  KISTA, SWEDEN                         Fax: +46 8 751 72 30

Newsgroup: sci.electronics
document_id: 54227
From: red@tina.dei.unipd.it (Piergiorgio Sartor 274199/IL)
Subject: PALs, GALs

Does anyone know how can I get detailed information about PALs and GALs.
Please reply via e-mail.
Thanks a lot in advance.
-- 
					red@paola.dei.unipd.it
					red@maya.dei.unipd.it

Newsgroup: sci.electronics
document_id: 54228
From: tde9106@hgs.se (Joakim Gunnarsson)
Subject: Re: How universal are phones these days?

wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:

>In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

>> I'm wondering if I can tote my American touch tone phone around with me
>> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
>> for that in Europe.  The question is if the general electronics work
>> the same.  I can buy a different wall plug and refit it (I'm sure I'd
>> have to), but would that do the trick?

>Two things to watch for:
>In Germany (and I think the same holds for Sweden) only some
>of the connections can handle tone dialing, so make sure the
>phone can be set to pulse dialing.
>In Sweden, the '0' is the first digit and all other digits
>are pushed "down" by one position; this makes dialing (and
>in the process converting numbers) an interesting task.

This is just basicly right. The connections that cannot handle touchtone dialing is very few. I would estimate a couple of percents and if you are in a bigger
town, there is none that cannot handle tone dialing.
And regarding our swedish dialing system (a rather screwd up system), that does
just apply to pulsdialing. Not to touchtone.
Btw; Norway is even more interesting. They got both system! So you need different phones depending on where in the country you live.

/Joakim Gunnarsson - tde9106@abacus.hgs.se


Newsgroup: sci.electronics
document_id: 54229
From: blumenow@underdog.ee.wits.ac.za (Warren Blumenow)
Subject: RF Communications Link

Hi.

Our problem is the following:

We have to design an RF link for a distance of 250 m.  We're using
standard RS232 waves (square pulses) as the modulating waves and the 
carrier wave is sinusoidal.  The link has to be bidirectional.
 
We would appreciate any advice on the type of modulating techniques
or antennas that we should use.

Please internet email us at:  007gjf3@witsvma.wits.ac.za  (Nando)
                         or   007bww3@witsvma.wits.ac.za  (Warren)
                         or   blumenow@underdog.ee.wits.ac.za  (Warren)

Thank you very much in advance.

N & W

Newsgroup: sci.electronics
document_id: 54230
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: Blue LED's

{Gladman Aviv} said
   "Re: Blue LED's"
      to <All> on 04-24-93  01:51

 GA> In order to emit blue light, a semiconductor must have a band gap
 GA> energy within the region of 2.6 to 2.8 electron Volts. According to my
 GA> physical electronics prof, you can't get an LED with that band gap.
 GA> That's why you don't find blue LEDs or, for that matter, some other
 GA> colour of LEDs. That is not to say that blue LEDs can't be found.  I've
 GA> seen 'blue' LEDs sold, but they were just your typical visible light
 GA> LED in a blue plastic covering. They didn't emit very much light...

    This is not true they have and do make blue LED's they are
    about 2.80 in digikey. 470nm wavelength by the way

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Sun  04-25-1993  at 13:33:46

... "I think 640K will be enough.." -Bill Gates 1981
___ Blue Wave/QWK v2.12
  

Newsgroup: sci.electronics
document_id: 54231
From: abjoern@idt.unit.no (Anders Bjoernestad)
Subject: Re: How universal are phones these days?

In article <1rgka2$n4k@corax.udac.uu.se>, tde9106@hgs.se (Joakim Gunnarsson) writes:
|> 
|> >Two things to watch for:
|> >In Germany (and I think the same holds for Sweden) only some
|> >of the connections can handle tone dialing, so make sure the
|> >phone can be set to pulse dialing.
|> >In Sweden, the '0' is the first digit and all other digits
|> >are pushed "down" by one position; this makes dialing (and
|> >in the process converting numbers) an interesting task.
|> 

I think all connections in Norway can handle touchtone dialing.

|> Not to touchtone.
|> Btw; Norway is even more interesting. They got both system! So you need different phones depending on where in the country you live.
|> 
The Oslo-region has one system, the rest of the country another system.

|> So you need different phones depending on where in the country you
|> live.
(Almost right for pulsdialing.)
Some phones have a little switch inside, so you are able to use them
all over Norway, or you can just renumber the numbers on your phone.



-- 
Anders Bj{\o}rnestad
Division of Computer Science and Telematics
Norwegian Inst. of Technology, Trondheim, Norway
Email : abjoern@idt.unit.no    (Internet)
X.400 : C=no; PRMD=uninett; O=unit; OU=idt; S=abjoern  

Newsgroup: sci.electronics
document_id: 54232
From: mje@sni.co.uk (Mike Evis)
Subject: Caltech PUFF PD ftp? RF Tools?

Hi there,

Does anyone know whether the PUFF RF design package is available
via ftp from any site? As I understand it, it is in the public
domain - please correct me if I'm wrong on this one.

Any other PD RF design tools out there that can be recommended?
Especially microstrip filter tools...

73's
Lehane

--
Lehane Kellett. G8KMH. Siemens Nixdorf Information Systems, Bracknell.
lehane@sni.co.uk Phone 0344 850393  Fax 0344 850401 Compuserve 100065,3563 
Standard disclaimers apply. Warranty void if opened.                    

Newsgroup: sci.electronics
document_id: 54233
From: mike@netnews.louisville.edu (Mike Harpe)
Subject: Re: How to drive an array of LEDs?

ptorre@hardy.u.washington.edu (Phil Torre) writes:

>I have a project in mind that requires an array of LEDs that can be addressed
>individually by a microprocessor (say, 16x16 or so).  Is there an LSI that
>is designed to drive an LED array (including RAM to hold the array state),
>or failing that, some way of multiplexing the display so I don't have to
>latch a bit for each LED using a discrete latch?  (I want to avoid having
>a huge board covered with 373s if possible!)  Thanks in advance...

Maxim makes a chip that does exactly what you want. The MAX7219 drives 8
7 segment LED displays with full decode or drives 64 discrete LED's with
a 3 wire serial interface.  The chips can also be cascaded to allow very
large arrays.  I am working on a sign display using this part.

I'll have to post the contact info for Maxim later, it's at home.  There was
a series of articles on this chip in the last couple of Circuit Cellar Ink's.

Mike Harpe
-- 
Michael Harpe, Programmer/Analyst      Information Technology, Ormsby Bldg.
mike@hermes.louisville.edu             University of Louisville
(502)588-5542                          Louisville, Ky. 40292
"He's not a man, he's a remorseless eating machine!" - The Simpsons

Newsgroup: sci.electronics
document_id: 54234
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: How to the disks copy protected.

Comments about "who needs backup copies"?  and "YOU do" deleted....

I'll toss in my 2 cents worth - I've begun to think that distribution
disks are made on some of the least reliable floppy disk stocks available.
We've been especially plagued by Borland's distribution disks.  I'm 
lucky if I can install from them as many as 3 times before they crap 
out on me.  So definitely, as a matter of course we ALWAYS make copies
to do our installations with.

--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
document_id: 54235
Subject: Re: How to the disks copy protected.
From: sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen)

Kuo-Sheng (Kasey) Chang (kschang@sfsuvax1.sfsu.edu) wrote:
> In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu>
> sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes: 

> > This is not a good idea.. I upgraded my motherboard last fall.  I >would
> have been quite pissed at any software that would have forced me to
> >reinstall simply because I changed motherboards. >

> Opinion is understandable.  :-)  I assume you have a tape drive?  Not all
> of us have about 200 floppies around for backup, you know.  

	Actually, no I don't have a tape drive.  In the event of a total
hard disk failure, I reinstall the apps from originals, and restore the data
from the backups I keep of that.  With upwards of 100Mb of stuff on my hard
disk, there is no way I'm going to try and back it all up without a tape
drive. :)  Would be nice to have one though!

> RAM is something you add all the time, so no.  It's more like BIOS
> manufacturer and/or processor type (386/486/etc).  Data cannot be used,
> esp with these new Flash ROM BIOS machines with updates on a diskette.

	Maybe, maybe not.  Today it doesn't happen as often (I would hope),
but then if a BIOS is buggy and the user gets an upgrade, the BIOS
information is going to change, at least the date anyway.  Tagging the BIOS
manufacturer is still going to falsely tag those users who upgrade the
motherboard.  This type of upgrade doesn't require a hard disk
backup/restore.

> On the other hand, to make this LESS intrusive it could be disguised as
> "Please Insert Original Disk #XX as I need file YYYYYY for update".  :-) 
> It would be perfectly reasonable...  Sort of.

	As long as it wasn't done too terribly often.  Otherwise I think it
would get annoying and the user would go looking for other software.

> > > This is silly.  It's much easier to loan disks to a friend and let
> >them do an install than to backup your copy already on disk, and then
> give >them that.  Your scheme isn't going to stop anyone. 

> Of course it is easier.  Are you saying then the originals SHOULD allow
> only one install?  What is your point?

	Of course not.  If something gets corrupted and my app needs to be
reinstalled, the *worst* thing I want that software telling me is "this
software has already been registered to <blank> and it is against the law to
install it on other machines."  Or something similar; Access for Windows
does this and it only requires a click on "OK" to go away.  Pretty
non-intrusive, but it gets the point across.

> What I said was the program should have certain restriction (such as the
> restrict-to-one-machine) UNTIL the program is registered with the
> manufacturer.  The manufacturer will then supply the
> then-proven-legitimate-user with a patch that will disable the restriction
> and PROUDLY PROCLAIM the legal copy with the "Registered to XXX" screen.

	This is a great idea.  I like the key system that some shareware
products use.  The only problem is that it will be difficult for big
software companies to implement this without it getting very
cost-ineffective for them and more of a burden than a benefit to the users.

--
Steve Madsen
sjmadsen@nextsrv.cas.muohio.edu

Ask me about Linux, the free 386 unix!

Newsgroup: sci.electronics
document_id: 54236
From: mbattist@magnus.acs.ohio-state.edu (Mark A Battisti)
Subject: Clear LCD or LED "sheets"

I am interested in finding a supplier for an array of leds on material which is
transparent when nothing is lit.

I'm not quite sure what LCD screens are like away from the laptop but I would 
guess they are not too clear.

An ideal item would be an LED array for which each LED is about 1/2" square.  
(Yes very course)  This is for distance viewing, but on a window.

Any pointers of suggestions would be much appreciated.

-Mark Battisti
mbattist@magnus.acs.ohio-state.edu

1940 Summit Street #B
Columbus, Ohio 43201
(614) 299-0317

Newsgroup: sci.electronics
document_id: 54237
From: mcarr@austin.onu.edu (Michael Carr (x1723))
Subject: Digital->AC Scaling


	Being in the "visualization" stage of a circuit design right now,
I was wondering what the best way to "scale" an AC voltage using an 8-bit
digital word is. I am thinking of using the common method of sending the
word through an ADC and then comparing it with the AC voltage (converted
to a sawtooth wave) to get a duty cycle. However, I am leary of this
method because it a) requires a lot of parts, and, more importantly, b)
creates a lot of interference from the switching on the entire AC line. I
realize that correct filtering could cancel out most of this interference,
but that would require more parts and boost the price further.
	Someone mentioned to me that they had seen an IC which input 8
bits of data and DIRECTLY scaled the AC voltage coming in all on-chip.
Unfortunately, he couldn't remember the chip number or the manufacturer;
if anyone else has heard of this chip, please e-mail me.
	I am building this project as a "dimmer box" for a light
controller circuit and it is important that the cost of each box remains
very low because one dimmer is required for each light that the user
wishes to control (well, each channel, at least). Therefor, if each box
costs $150, I doubt that an end user will want to dish out ($150 x 16 =
$2400) for sixteen channels... This is something I have noticed about
today's dimmer boxes; they are so expensive!
	Anyway, any help which someone could offer on either a method of
easily doing this or info about the chip which will do it for me (always
the preferred method... :) will be greatly appreciated!

	Michael Carr
	m-carr@onu.edu


Newsgroup: sci.electronics
document_id: 54238
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: RF Communications Link

In article <blumenow.7@underdog.ee.wits.ac.za> blumenow@underdog.ee.wits.ac.za (Warren Blumenow) writes:
>We have to design an RF link for a distance of 250 m.  We're using
>standard RS232 waves (square pulses) as the modulating waves and the 
>carrier wave is sinusoidal.  The link has to be bidirectional.
>We would appreciate any advice on the type of modulating techniques
>or antennas that we should use.

What frequency is your carrier?

Have you considered using two tones, one for 1 and another for 0?

How high is your RS-232 data rate?

Can you use more than one carrier freq?

Have you considered hiring an RF data transmission consultant?

Just Curious,
Galen Watts, KF0YJ


Newsgroup: sci.electronics
document_id: 54239
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Power, signal surges in home...

In article <1993Apr26.045628.5617@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>brian@ucsd.edu (Brian Kantor) writes:
>
>: Listen to the interference.  If you hear voices clearly, it almost
>: certainly ISN'T ham radio, and might well be CB.  If you can record a
>: bit of it, you could take the tape over to a local ham operator's house
>: and ask him for his opinion of what you're hearing.  Most communities
>
>You cannot do that legally. 

Why can't he record it legally?  It may not be admissable in court, but
recording for personal use is legal.  If he wants to play it for his ham
friend, that's legal too, as long as he doesn't charge admission.

>Unfortunately, most consumer equipment is succeptable - it is all poorly
>designed.

Here, Here!
>
>: (BTW: hams are ALLOWED amplifiers; CB isn't.  "illegal ham amplifier"
>: doesn't compute.)
>
>It does, but not for a mobile radio. There are very few mobile rigs that
>could power a 1500 watt amplifier.
>Bill

It doesn't actually have to be 1500 watts at 100 feet.  I've heard radio
transmissions from concert security over guitar amps with no guitar plugged
in, and security uses radios transmitting 2-5 watts into a rubber duck antenna,
which acts more like a dummy load than an antenna.

Hey Bill, where were you three weeks ago when all this stuff was posted
and dealt with?

Galen Watts, KF0YJ


Newsgroup: sci.electronics
document_id: 54240
From: kpjone01@ulkyvx.louisville.edu
Subject: What type of IC is this???

Greets,
 
I have an IC I need help in identifying.  It is an 8-pin IC with the following
label:  W03563  9144w4  
 
ANY help would be greatly appreciated in identifying this chip.  
 
Kevin


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kevin Jones                                   KPJONE01@ULKYVX.CT.LOUISVILLE.EDU
Lab Supervisor                                KPJONE01@ULKYVX.LOUISVILLE.EDU
Computing and Telecommunications              PHONE:  502-588-6303
University of Louisville, KY                  FAX:    502-588-0150

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                 The only good racist is a dead racist.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Newsgroup: sci.electronics
document_id: 54241
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: HELP!  Looking for Oscilloscope source

Hi all,

I am looking for a new oscilloscope (BK 1541-B, it looks like, Goldstar OS904S
if I can find one cheap enough) and would like suggestions on a low-priced
source for them.

(Currently, BTW, Fry's electronics in Los Angeles has the 1541-B for $598,
 the best price I've seen overall for now - They carry the GS OS902S for 
 $490, but I need the 904S because of the 40 MHz B/W)

Thanks all.
-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
document_id: 54242
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: Clear LCD or LED "sheets"

mbattist@magnus.acs.ohio-state.edu (Mark A Battisti) writes:

>I am interested in finding a supplier for an array of leds on material which is
>transparent when nothing is lit.

>I'm not quite sure what LCD screens are like away from the laptop but I would 
>guess they are not too clear.

>An ideal item would be an LED array for which each LED is about 1/2" square.  
>(Yes very course)  This is for distance viewing, but on a window.

>Any pointers of suggestions would be much appreciated.

What, pray tell, are you putting together?  And what about costs?  And does it
have to be transparent as in totally transparent?  Or just transparent enough
to allow light from the other side to shine through?

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
document_id: 54243
From: long@spk.hp.com (Jerry Long)
Subject: Re: 2% silver solder

Andy Shiekh (shiekh@ictp.trieste.it) wrote:
:   I have seen the existance of electronics solder with a 2% silver
: content that seems to have good wetting and fatique reatings.
:   Can anyone tell me why it is not used? (silver is not such an expensive
: metal).
: 
: 
: Andy
: 

For the most part, silver-solder is not used for general soldering
tasks due to the mechanism of dendritic growth. Silver-solder, when
exposed to high humidity and placed in an electric field, will actually
grow dendrites which are conductive and will adventually electrically
short across closely spaced nodes which are creating the field. For this 
reason, silver is allowed only in hermetically sealed assemblies.
Fortunatly, tin-lead solder is quite stable and will not grow dendrites
as fast as silver-solder. Therefore, it is used extensively.

 
Jerry Long

long@spk.hp.com
****************************************
Disclaimer.... Opinions are my own and
do NOT reflect those of my employer.  
**************************************** 

Newsgroup: sci.electronics
document_id: 54244
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Laser vs Bubblejet?

There is a cartridge capping upgrade for older deskjet printers
available from hewlett-packard.  Older original deskjet and
possibly deskjet 500 units may have a black plastic slide with
rubber capping components in the cartrige parking area on the right
side (viewed from front) of the printer.  Newer printers have a
gray or white plastic slide.  The black plastic slide can allow
your cartridge to dry out.  There was and may still be information
packaged with ink cartridges explaining the situation.  HP placed a
coupon for a free upgrade kit to modernize old deskjets to the new
capping mechanism.  I did this on my printer and did indeed find
that the cartidges now last longer.

I don't have the information handy.  I suggest contacting your
nearest HP service center for information on obtaining the kit.

HP has upgrade kits that consist of electronics and mechanical
components that vary depending on the starting level printer and
the level to which you wish to upgrade.  I upgraded my original
desket to a dekjet 500.  The kit was fairly expensive.  You are
likely better off selling your old printer and purchasing a new
deskjet 500 now that prices have declined so much.  Upgrading an
original deskjet to 500 requires a fair amount of skill, but no
soldering.  Upgrading a deskjet plus to a 500 is involves swapping
the processor card and changing a few minor parts.  Contact your HP
service center for further information.

The PCL language used by Deskjets is considerably different from
the PCL used by laser printers, especially the newer laser
printers.  The biggest problem is dumb laser drivers that send a
raster end command after each scan line.  This makes no material
difference for lasers, but causes the deskjet to print the
accumulated raster.  As you might guess, the result is hideously
slow printing.  The new DOS Wordperfect print deskjet drivers are
still guilty of this particular behavior.  From the way Wordperfect
works, this would not be easy to change.  Windows Wordperfect works
efficiently unless you use the DOS drivers instead of Windows'.

The PCL4 dialect used in the Laserjet IIIP allows compression that
permits a full page 300 dpi image to be rendered with only one
megabyte of memory.  An uncompressed image could be as large as
about 909 Kbytes, but the printer needs about 300K of memory for
its internal house-keeping.  Laserjet IV models support banded
printing that allows incrmental download of the image with
compression in limited memory situations.  Deskjet downloadable
fonts are not compatible with laserjet fonts.

A single page from a laserjet only requires about 20 seconds.  This
is faster than any but the most trivial printing from a deskjet
printer.  The presumption, of course, being that the laser printer
has completed its warm-up cyle.

Until ink chemistry is changed, wicking resulting in image
deterioration is unavoidable.  I won't use the word impossible, but
matching laser quality output from a deskjet printer is unlikely.
Chosing an appropriate paper type helps, but does not eliminate the
problem.

Laser printers are more wastful of energy and consumable
components.  HP does accept return of spent toner cartridges,
mitigating the material waste problem to a degree.  Energy waste
could use more work.  Warm-up times have decreased, allowing
stand-by current consumption to be significantly reduced in the
laserjet IV.

Kyocera produces a laser print engine that employs an amorphous
silicon imaging drum with a replacable toner system.  The image
drum is good for approximately 100K copies.  It is a very nice
print engine.  I wish HP used the Kyocera engine.  Kyocera also has
a neat modular paper source and stacker system.

The recommended duty cycle for a deskjet is significantly lower
than any of HP's laser printers.  The pick-up pressure rollers are
subject to wear and I case confirm eventually do wear out.  The
usual symptom is that the printer becomes reluctant to feed paper.
The paper feed is integrated in a transport mechanism that is a
single part from HP service.  Replacement cost for the transport is
almost $200.  The feed rollers are not separately replacable,
though it would not be a difficult job for a competent technician.
I have disassembled and reassembled the transport on my own printer.

It depends upon the application which printer is best for you.  If
you only print 5 or 10 pages a day and are satisfied with the
appearance of output, the deskjet is a very good choice.  As noted,
the deskjet 500 is my choice for personal use.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 54245
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Blue LED's

Baden de Bari (baden@inqmind.bison.mb.ca) wrote:
:  
:         So what's the story here... we're all stuck with the regular
: green, red, and off yellow-orange LED's!?  What gives!!??
:         Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???

If your looking for LEDs in the $.10-$.20 range, forget it. Blue LEDs just
recently became available and the materials they are made of are expensive.
Maybe in the future they will become less expensive (and brighter), but
for now it's going to cost you and the output will be limited. If they ever
do get as efficient and cost effective as red and green LEDs, you're probably
going to see a whole new family of color displays.

         Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
document_id: 54246
From: bomr@erich.triumf.ca (Rod Nussbaumer)
Subject: Re: multiple inputs for PC

In article <93114.142835U19250@uicvm.uic.edu>, <U19250@uicvm.uic.edu> writes...
>Can anyone offer a suggestion on a problem I am having?
>I have several boards whose sole purpose is to decode DTMF tones and send
>the resultant in ASCII to a PC.  These boards run on the serial interface.
>I need to run * of the boards somwehat simultaneously.  I need to be able to ho
>ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
>PC inexpensivley, so that all can send data simulataneously (or close to it)?
>Any help would be greatly appreciated!
>Abhin Singla
If you can modify the design of the DTMF decoder, the ideal comunications
would be over a multi-drop system, like RS-485.  RS-485 boards are available
for PC's, probably cheaper than a bunch of RS-232 channels, and RS-485 is
cheaper to build onto your satellite modules, using only a single supply
8-pin DIP driver chip.  Software at the PC end would be similarly complex
for either RS-232 or RS-485, in my opinion.  The higher data rates possible
with RS-485 would permit quasi-simultaneous data transmission.
Hope this helps.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Rod Nussbaumer, Programmer/Technologist       Bitnet: BOMR@TRIUMFER
  TRIUMF --- University of British Columbia,  Internet: bomr@erich.triumf.ca
  Vancouver, BC, Canada.                         Phone: (604)222-1047 ext 510
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Newsgroup: sci.electronics
document_id: 54247
From: kniha@carson.u.washington.edu (Dagmar Amtmann)
Subject: Re: How universal are phones these days?

I don't know much about phones in Germany, but this is what I know: I bought
a phone in the U.S. for my mother who lives in Bratislava, Slovakia and it
works just fine. The problem is they don't have wall jacks like we do here.
There is a wire without any jack at the end sticking out of the wall. So you
need to connect the wires (I'm not sure if they have wall jacks in Western
Europe - they may). Hope this helps. Dagmar kniha@carson.u.washington.edu


Newsgroup: sci.electronics
document_id: 54248
From: gornish@sp1.csrd.uiuc.edu (Edward H. Gornish)
Subject: Radar/Laser Detectors

What are people's opinions about laser detectors?  Escort makes a
laser detector, the Passport 1000, and claims it works fine.  However,
I've talked to some people who have said that it will only work if you
are lucky - i.e. if the cop happens to point his laser at a car in
front of you, and the laser beam happens to reflect back to your
detector.  Otherwise it won't work.  Regular radar, of course, travels
in all directions; hence it is more detectable.  Any comments?

Escort has a deal (till the end of April, I think), where if you buy
their wideband (Passport 3200 - X, K, Ka) and laser detectors, you'll
save $60 off of buying them separately.  In this case, the addition of
the laser detector over the Passport 3200 is only $40 (i.e. Passport
1000 normally costs $100).
--
Eddie Gornish
University of Illinois - Center for Supercomputing Research & Development

gornish@csrd.uiuc.edu

Newsgroup: sci.electronics
document_id: 54249
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: How do you build neural networks?

In article <1rbs1e$m6s@insti.physics.sunysb.edu> mmoss@ic.sunysb.edu (Matthew D  
Moss) writes:
> 
> Subject says it all, though I should specify that I'm looking for solutions
> that DON'T require me purchasing specific chips, etc....
> 
First you find a congenial member of the opposite sex ...
> 
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu

I couldn't resist :-)

Newsgroup: sci.electronics
document_id: 54250
From: u009@csx.cciw.ca (G. Stewart Beal)
Subject: Re: Caltech PUFF PD ftp? RF Tools?

In article <1993Apr26.124340.28057@sni.co.uk> mje@sni.co.uk (Mike Evis) writes:
>Hi there,
>
>Does anyone know whether the PUFF RF design package is available
>via ftp from any site? As I understand it, it is in the public
>domain - please correct me if I'm wrong on this one.
>
PUFF is sold by CalTech, although very inexpensively for the quality.
Source was also available for the earlier releases for a nominal charge,
but I'm not sure if this practise is continued.

 
Regards, Stu Beal, VE3MWM, U009@CSX.CCIW.CA,
National Water Research Institute, Burlington, Ontario, Canada.
 
"We'd made it through yet another nuclear winter and
 the lawn had just trapped and eaten its first robin." - Kyle J. Spiller


Newsgroup: sci.electronics
document_id: 54251
From: arnief@sail.LABS.TEK.COM (Arnie Frisch)
Subject: Re: Luser!

In article <1993Apr23.205906.10745@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for a high speed 
>D-to-A converter ( at least 8 bits
>and 150MHz) for testing a chip - any
>ideas on where I can find such a monster?
>A paper in the January issue of IEEE Journal
>of Solid-State Circuits (authors from Philips
>Eindhoven) mentions a 1GHz, 8bits, GaAs DAC
>they use in their testing, so I know that 
>such circuits are around somewhere.




TriQuint (Beaverton, Oregon), has been selling an 8 bit, 1 GHz D to A
for several years.  I have used it and it works well, faster settling
time and smaller glitch area than any video d DACs I have seen.  Also,
they have been developing a more precise version that may be for sale
now - it's somewhere in the 10 to 12 bit area at 1 GHz.


Arnold Frisch
Tektronix Laboratories

Newsgroup: sci.electronics
document_id: 54252
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: Why circuit boards are green?

kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:

>Not that the question is anything important, but I am still curious:
>Why is that almost all printed circuit boards are green? I have seen
>a few blue ones, but no red, yellow, company logo etc. Is there a
>technical reason or could it be that the marketing "geniuses" have
>not tought about it (yet)?

The green layer is a solder-mask, and is used to make a finished board
look neat, and to avoid solder bridges, especially when using wave
soldering (or any other mechanized approach). I've seen red mask,
but most that I've seen are green.

A bakelite board will look brown in colour, and, if the solder mask
is put on, looks like a brown board with green 'paint' on either side
(or just one side) of the board.
A fibreglass board will look green from the side, because the green
solder-mask makes the board appear that colour. If you got a fibreglass
board with no mask, it would be a whitish-grey colour.
Teflon boards do exist, as well... but I'm not sure about that one.

I'd guess the stuff they invented for solder mask was green, so they're
not about to change. Also, any change in any chemical probably requires
a better than normal cleaning of the machines that make boards. A lot
of companies do not make their own boards... they ship them to a real
boardhouse. 



Newsgroup: sci.electronics
document_id: 54253
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <Apr23.223805.66909@yuma.ACNS.ColoState.EDU>
jmiller@terra.colostate.edu (Jeff Miller) writes: 

>In an earlier article Kasey Chang wrote:

>: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>: via MAIL by mailing in your registration card, THEN the company send you
>: the patch which includes the info you put on the registration card.

>The problem with this scheme, is that when I buy a game, I want to play it
>*THAT* day...mailing a card to and from California would probably take a week
>or more.

I didn't say the program is DISABLED, did I?  (I HATE!!!! it when people
take my words out of context...)  I mean that once you have installed it,
you cannot DEinstall it without registering it, or transfer it to another
machine, or SOME SORT OF LIMITATION (the author will decide), WHICH WILL
BE REMOVED WHEN THE PROGRAM IS REGISTERED.  

--Kasey Chang


Newsgroup: sci.electronics
document_id: 54254
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: What type of IC is this???

In article <1993Apr26.104008.1@ulkyvx.louisville.edu> kpjone01@ulkyvx.louisville.edu writes:
>I have an IC I need help in identifying.  It is an 8-pin IC with the following
>label:  W03563  9144w4  

The 9144w4 is the date code but none of my books list a W03563.
What is it out of and can you tell us what kind of circuit it is in?

In the odd case that 9144w4 is not the date code, NTE says a 9144-60
is an AM reciever subsystem and a 9144-61 is an FM subsystem, but these
are both in 16 pin packages.

More Info, Please!
Galewn Watts, KF0YJ


Newsgroup: sci.electronics
document_id: 54255
From: dave@imax.imax.com (Dave Martindale)
Subject: Re: NTSC horiz & vert drive from black burst?

jackp@NETSYS.COM (Jack Powers) writes:
>I would like to hook up some cameras that were recently donated to our
>local community cable TV station which have sync inputs in the form
>of horizontal and vertical drive. Our station sync is a black burst
>which works fine with other boxes with "genlock" style inputs. Can
>anyone point me at a design, article, or whatever showing how to produce
>the horizontal & vertical drive signals?

Check the station's master sync generator.  You'll probably find that
it already has horizontal and vertical drive outputs that just aren't
being used.  A couple of cables and you're in business.

Another possibility is to find a genlockable sync generator with HD and VD
outputs - genlock it to station sync, and then feed HD and VD to the
cameras.

If neither of these is possible, then you'll have to build a sync
separator.  Look at the circuit diagrams of your existing sync generators -
they probably all include circuitry that does what you want.

	Dave

Newsgroup: sci.electronics
document_id: 54256
From: ruhtra@turing.toronto.edu (Arthur Tateishi)
Subject: Features for answering machines(esp. digital)


Hello, I'm curious what sort of neat features exist on high-end
answering machines today. In particular, I'm interested in
features of digital answering machines. Also, what is the
typical amount of storage(in minutes) for these digital answering
machines?

The reason? I'm hacking together an answering machine program
for my ZyXEL modem and I'm wondering if I'm missing something
on my wish list.

arthur
-- 
"The first fact to face is that UNIX was not developed with security, in any
reliable sense, in mind; this fact alone guarantees a vast number of holes."
    -- "On the Security of UNIX", Dennis M. Ritchie
Arthur Tateishi                 ruhtra@turing.utoronto.ca

Newsgroup: sci.electronics
document_id: 54257
From: agodwin@acorn.co.uk (Adrian Godwin)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr26.074500.13256@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:

# when soaking in water). Lasers are slightly sharper, but the only
# instance where I needed precise layouts was Printed Circuit Board
# Transparencies for PhotoEtching. I found a Textronix color Phaser
# Postscript (Thermal Wax Transfer) to work the best to make PCB
# negatives directly onto a transparency.
# 

Did the deskjet work at all when printing on transparencies ? If it
did, what sort of resolution could it manage ?

-adrian


-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.

Newsgroup: sci.electronics
document_id: 54258
From: mgc@unislc.slc.unisys.com (Marc Christensen)
Subject: Re: descrambling channels

Sean Oliver (Sean_Oliver@mindlink.bc.ca) wrote:
: I live up in British Columbia, Canada.The cable company I use is called
: Rogers Cable. Does anyone know of their scrambling techniques, and ways of
: getting
: around them? Any suggestions of what they might use?
: 
I don't know the answer to your question, but I am sure Rogers Cable can so
I tool the libery of forwarding your question to them and I am sure they
will be in touch. :-)

Marc Christensen

Newsgroup: sci.electronics
document_id: 54259
From: ruck@beach.cis.ufl.edu (John Ruckstuhl)
Subject: solvent for duct-tape adhesive?

I know this is a long shot, but does anyone know what solvent I should 
use to clean duct-tape adhesive from carpet?
Someone taped wires to the carpet, and now it is time to move out.

Is the solvent the same as what's used to clean up the goop in coax?
(whatever that is ... but it just barely ties this query into 
sci.electronics)

Thanks for your help
Best regards,
ruck
-- 
John R Ruckstuhl, Jr                    ruck@alpha.ee.ufl.edu
Dept of Electrical Engineering          ruck@cis.ufl.edu, uflorida!ruck
University of Florida                   ruck%sphere@cis.ufl.edu, sphere!ruck

Newsgroup: sci.electronics
document_id: 54260
From: tas@fermi.clas.Virginia.EDU (Thomas A. Spraggins)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:
>Otherwise, it is technically no problem to connect a foreign
>phone to either the German or Swedish phone system.
>OTOH neither you nor I would ever try that, as it is of course
>illegal.

Oh yes, the good ol' deutsche Bundespost.  Shortly after moving to Germany,
someone told me that "POST" is an acronym for the "Public Organization for
the Suppression of Technology".  Stimmt, oder?

I miss a lot of things about Germany (yes, including the Bier vending
machines at work that were SUBSIDIZED by the firm), but the phone system
is not one of them.

Tom Spraggins
tas@virginia.edu

Newsgroup: sci.electronics
document_id: 54261
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: Removing battery corrosion

From article <1993Apr25.201129.1239@Princeton.EDU>, by fuchs@tsar.princeton.edu (Ira H. Fuchs):
> Is there a readily available solvent that does a good job at removing the  
> corrosion/encrustation that collects on the battery terminals (usually the  
> cathode) when using alkaline batteries (or more accurately, when NOT using  
> them for a long time)? 
 generally,  the corrosion is a signal that it's time to send them
 of to the recyclers, but if you're that desperate or cheap try 
baking soda and a wire brush. use gloves and goggles, please!

Newsgroup: sci.electronics
document_id: 54262
From: ree88132@zach.fit.edu (Keith Ledig)
Subject: References for ANY IC

I am looking for a text/reference that will include pinouts, 
description, and functionality for just about any IC made.
Does such a text exist?  Are there docs on the Internet that
reference IC's?  It would be a great idea if each major
IC manufacturer made available to the public an anonymous
FTP site with all it's data books in the form of text files.
(ala RFC style).  This would save time and money for the
IC manufacturer since a text file costs nothing to send
around the world via internet and since most users of
IC's
are found in the internet anyway.  

Are there any books available for purchase that reference
(as many as possible)?  Or am I going to be stuck obtaining
a zillion databooks from the manufacturers (those little
phonebook-type books that are obsoleted every couple years)

:-(



Newsgroup: sci.electronics
document_id: 54263
From: mbattist@magnus.acs.ohio-state.edu (Mark A Battisti)
Subject: Re: Clear LCD or LED "sheets"

>>An ideal item would be an LED array for which each LED is about 1/2" square.
>>(Yes very coarse)  This is for distance viewing, but on a window.
>>Any pointers of suggestions would be much appreciated.
>
>What, pray tell, are you putting together?  And what about costs?  And does it
>have to be transparent as in totally transparent?  Or just transparent enough
>to allow light from the other side to shine through?

Yes it has to be very clear (like it wasn't there).  And of course, cost is 
always a factor.  I am trying to get an idea of the feasability of such an 
idea.  But I don't want to give too much away.

-Mark

Newsgroup: sci.electronics
document_id: 54264
From: rowley@netcom.com (Thomas Rowley)
Subject: Re: Voice synth chips

Alltronics in San Jose (408) 943-9773 sells the Votrax Sc-01 Speech Synthesis 
chip for about $5.00. Also I noticed that Radio Shack sells the ISD chip which
 will store small amounts of digitized speech. 

Good Luck




Newsgroup: sci.electronics
document_id: 54265
From: einari@rhi.hi.is (Einar Indridason)
Subject: Re: How to the disks copy protected.

In <1993Apr26.163640.27632@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>In article <Apr23.223805.66909@yuma.ACNS.ColoState.EDU>
>jmiller@terra.colostate.edu (Jeff Miller) writes: 

>>In an earlier article Kasey Chang wrote:

>>: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>>: via MAIL by mailing in your registration card, THEN the company send you
>>: the patch which includes the info you put on the registration card.

>>The problem with this scheme, is that when I buy a game, I want to play it
>>*THAT* day...mailing a card to and from California would probably take a week
>>or more.

>I didn't say the program is DISABLED, did I?  (I HATE!!!! it when people
>take my words out of context...)  I mean that once you have installed it,
>you cannot DEinstall it without registering it, or transfer it to another
>machine, or SOME SORT OF LIMITATION (the author will decide), WHICH WILL
>BE REMOVED WHEN THE PROGRAM IS REGISTERED.  


WHAT??!!!!

You can't remove it, unless you register?  
You gotta be joking, right?
What happens if I get a demo-version of that program, install it, and then
decide that I don't like it.  Do I have to register to be able to get rid
of it?  (Hell, no, that is the last thing I would think of!)
If that is what you mean, then you would better make pretty sure, that a
statement to that effect is printed loud and clear on the package!


A better way to implement the above mentioned scheme is (IMHO) to allow
anyone to install the program, but if they register, they get some
additional features enabled.  It could mean only one new .EXE file needed
to be copied, to have got the full-version of the program.
Of course anyone is _free_ to _delete_ or _remove_ that program at whatever
time they like.

Still, we face the trouble of 'moving' the new .EXE file around.  That
could be solved by having the user registering him self, and get back a
specially marked for him (or her) a new .exe file.


As for some sort of limitations, here are some suggestions:
Limit the size of data that the program can work with,
Disable saving the data,
Print it out with some defects in the output (but be sure to mark them as
such)
Let some pop-up screen appear for ca. 10 secs. when the program is started
and/or exited

etc....
but DON'T have it that you _must_ register to be able to remove it.



--
einari@rhi.hi.is

Newsgroup: sci.electronics
document_id: 54266
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Flexible solar cells

In article <1993Apr22.135517.5897@r-node.hub.org> wayne@r-node.hub.org (Wayne Dawe) writes:
>Two or three years ago I saw a report on TV about a company that had 
>developed a method of making solar cells on a flexible substrate. My
>failing memory has convinced me it was some flexible metal. I now have
>an application that requires a flexible solar cell and was hoping someone
>out in netland knows something about this company or a similar product.
>Any help would be greatly appreciated.
>-- 
>Wayne Dawe                    (pick a path, any path but don't send me
>wayne@r-node.hub.org           anything bigger than 15K)
>wayne@r-node.gts.org   wayne@r-node.pci.on.ca     wayne@r-node.UUCP

Wayne:

Look for these advertised in sailboat supplies catalogs and sail-related
magazines (eg. SAIL ...).

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
document_id: 54267
From: warren@eggo.csee.usf.edu (Warren Gaiewski)
Subject: Re: D,G,&H type Amplifiers

in article  <735604750.28979.0@unix5.andrew.cmu.edu>,  Mark Yeck
writes:

--------->

Hey, can someone clue me in on these and other weird types of amplifiers?  Just
a brief intro to the concepts behind these would be cool.  I have the clues 
on type A, B, and AB already and stuff, but these other ones are mentioned 
occasionally and I dont know what they do.  I think type D is like a PWM scheme
or something.  Thanx in advanced.

---------->
The whole point to these weird amplifier types is improved efficiency.

Class D amps *are* PWM (pulse width modulation) amps which work very much like
switching power supplies. I think I've seen these things called "class S"
before as well. They're capable of very high efficiencies, and would be suitable
for very high power. I've yet to see anything like this used in an audiophile
amp, though.  I've been trying to design a three-kilowatter for the last year
(to be used as an inverter for an UPS), but have been having serious problems
with layout parasitics (10 IRF 450's in parallel... any help  with a  do-able
isolated drive ckt would be appreciated :) ) 

I'm not absolutely positive about this, but I beleive a 'class G' amp is one that
operates off a variable- or switched power supply rail voltage. The Carver
amps do something like this. They use some sort of phase-control circuit 
(I do not fully understand its operation) to reduce the transformer size, and
I beleive that is patented. I had an M400 apart (trying to fix) and found that
it had three rail voltages that it switched between. I ran a simulation on
PSPICE and found that the topology would greatly reduce power dissipation (heat)
under large-signal conditions, or when driving reactive loads (which draw high
current at the zero-voltage crossings). 

Think SPEAKER.......             /|              Dr. Diode
                              ||/ |           ------|>|------
 "Great sound  starts with    ||  |           warren@eggo.csee.usf.edu
      The Source"             ||\ |           warren@renoir.cftnet.com
                                 \|                




Newsgroup: sci.electronics
document_id: 54268
From: u95_dgold@vaxc.stevens-tech.edu
Subject: EMI filter, What's in it?

Could someone tell me what's in a Cornell-Dubilier EMI Filter
FIL 3363-001?

It is rated at 13A 115/250VAC 50/60HZ.  Is it just MOV's and ferrite?

Dave  /  n2mxx
Stevens Institute of Technology
Hoboken, New Jersey

Newsgroup: sci.electronics
document_id: 54269
From: alung@megatest.com (Aaron Lung)
Subject: Re: how to get rid of flyback whine?

In article <1993Apr26.012517.23391@Princeton.EDU> jsm@shade.Princeton.EDU (John Scott McCauley Jr.) writes:
>I recently took apart my color Sony TV to clean the volume pushbuttons and
>when I put the beast back together, the flyback whine got much louder.
>
>Is this easy to fix? Which part is resonating? I have heard rumors of a
>spray that will fix the noise.  Is this a simple thing for a TV repairman
>to fix?
>
>	Thanks,
>
>		Scott

Ah-ha!  I'm not alone at last!  Which Sony do you have??  I have a
27"SXR (pre-XBR series, circa 1987).  That damn thing used to
make noise like a mad-man.  I had/have 2 separate problems...one being the
flyback, the other was the assembly where the windings of the yoke
came together. 

First:  I found by poking around the windings on that assembly,
the thing would make noise.  I guess that there was enough of a potential
in that assembly to leak, so I sprayed it with a dielectric insulation
spray--I think it was urethane or acyrilic.  That fixed it.

Second:  Flyback...for the life of me, I can't isolate this one.  If I
leave the cover off, the TV will be quiet.  If I put the cover back on,
and let it heat up, it'll start to whine--kinda hard to solve with the
cover on!! :-(

A friend of mine who used to fix TV's says there might be a pin-hole
leak somewhere on the flyback.  Usually it's surrounded by a bunch of
black dust/dirt.

I hope this is a start...if you find something out, let me know!

aaron


Newsgroup: sci.electronics
document_id: 54270
From: iturriag@utkvx.utk.edu (Mr. Y)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de>, wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes...
>In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:
> 
>> I'm wondering if I can tote my American touch tone phone around with me
>> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
>> for that in Europe.  The question is if the general electronics work
>> the same.  I can buy a different wall plug and refit it (I'm sure I'd
>> have to), but would that do the trick?
> 
>Two things to watch for:
>In Germany (and I think the same holds for Sweden) only some
>of the connections can handle tone dialing, so make sure the
>phone can be set to pulse dialing.
>In Sweden, the '0' is the first digit and all other digits
>are pushed "down" by one position; this makes dialing (and
>in the process converting numbers) an interesting task.
>Otherwise, it is technically no problem to connect a foreign
>phone to either the German or Swedish phone system.
>OTOH neither you nor I would ever try that, as it is of course
>illegal.
>-- 

I am not quite so sure about the illegality of using a regular American phone
on your home system. I vaguely remember a few years ago, when "Deutsche
Bundespost" split into Postdienst, Postbank, and Telekom there was some
discussion about a new regulation. I know that cordless or cellular phones
still have to be approved by the Telekom, but does that hold true for regular
phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use
touch-tone dialing. I assume, however, that most areas are still exclusively
set to pulse dialing. Last time I checked (Jan '93) the Cologne areacode 221
was still solely pulse dialing.

BTW, touch tone does become more common in Germany, bringin with it the
flourishing of 1-900 services (in Germany 0190). I just hope we'll all have
ISDN some time at an affordable price - idle wishes...

Markus Iturriaga                
                           "Things go smoother with lard!"
iturriag@utkvx.utk.edu       "Bring back the glory that was grease!" 
iturriag@utkvx.bitnet           -East Tennessee Lard Advisory Council  

                            MILLARD FILLMORE LIVES!   

===============We've=got=what=it=takes=to=take=what=you've=got.=================

Newsgroup: sci.electronics
document_id: 54271
From: fennell@well.sf.ca.us (Michael Daniel Fennell)
Subject: Re: Why circuit boards are green?


Why are circuit boards green?  The material used to make them goes by two
names.  If it is used to make circuit boards it is called FR-4.  The same
material is used in the cryogenics industrya and marine industries as a
structural material and is called G-10.  FR-4 and G-10 are both green.  They
are not green because of a solder masking agent.  The basic ingredients are
a clear epoxy resin and glass fibers.  I am not sure what the specs are on
the resin, but if you are really curious you can call NEMA (National
Electronics Manufacturing Association) or Ciba Geigy (a major manufacturer
of epoxy resins) to find out.  As an aside, I occasionally mix clear epoxy
and glass microsphres to cast small structures for cryogenics experiments.
The proportions of glass to epoxy are about the same as in G-10.  They are
the same green color.

Newsgroup: sci.electronics
document_id: 54272
From: mdgoodma@apgea.army.mil (Malcolm D. Goodman <mdgoodma>)
Subject: Fiber Optic Modems For Sale *** CHEAP ***

OK I sold all but these, I had some offers and I accepted an offer
of 25.00 for the pair from bdale@gag.com ( Bdale Garbee ).  I don't
know what happened to him but he won't reply now that I accepted
it so I'll offer these again.
> 
> PLease take these and use them.  Take advantage of me... I really
> don't know what they are worth.
> 
> Qty 2  -  Canoga Perkins Fiber Optic Modems, Model 2250, RS-422
>           Interface, appear new.  I have powered up but that's all,
>           I have not used them and I cannot tell you whether they
>           work or not.    
>                                  Make Offer.........
> 
> Thanks and please buy this stuff or it goes out the door
> 
> Mack
> mdgoodma@cbda8.apgea.army.mil
> ..


Newsgroup: sci.electronics
document_id: 54273
From: mcmahan@netcom.com (Dave Mc Mahan)
Subject: Re: References for ANY IC

 In a previous article, ree88132@zach.fit.edu (Keith Ledig) writes:
>I am looking for a text/reference that will include pinouts, 
>description, and functionality for just about any IC made.
>Does such a text exist?  Are there docs on the Internet that
>reference IC's?  It would be a great idea if each major
>IC manufacturer made available to the public an anonymous
>FTP site with all it's data books in the form of text files.
>(ala RFC style).  This would save time and money for the
>IC manufacturer since a text file costs nothing to send
>around the world via internet and since most users of
>IC's are found in the internet anyway.  
>
>Are there any books available for purchase that reference
>(as many as possible)?  Or am I going to be stuck obtaining
>a zillion databooks from the manufacturers (those little
>phonebook-type books that are obsoleted every couple years)

We use a CD-ROM based system here.  There are about 45 CD-ROM disks and a
4-disk changer hooked to a dedicated MS-DOS computer.  It contains scanned
images of data book pages for several thousand parts.  When you ask it for
something it knows about (mostly active IC parts), it works quite well.
THey don't handle all the varieties of transistors or diodes that exist.
It is definately a start in the right direction, but they need to expand
the data base to handle more types of stuff.

These systems aren't cheap.  We paid about $7,000 for the liscence and get
monthly updates of some of the CD-ROM disks.  We send the old ones back to
them so that they will keep sending us the updates.  I think we pay a
yearly maintainence fee of about $1,500 to get the updates.

If you find the part you want, you can look at the data sheet on a
page-sized monitor (it's a special monitor from SigmaSystems).  You can
also print each page of the datasheet you want on a LaserJet printer.  Page
printing takes a couple of minutes per page.  It can take a while to dump
the 5 or 6 pages you usually need.

I have a feeling the maker wouldn't like it if we made the data available
to all Internet users.    :-)

  -dave

-- 
Dave McMahan                            mcmahan@netcom.com
                                        37N 17.382    121W 59.190 

Newsgroup: sci.electronics
document_id: 54274
From: Christopher Kristof <ck3i+@andrew.cmu.edu>
Subject: ??? Mystery Part ???

    I have a mystery part labeled NEC AC100.  It's from the low voltage
supply of an NEC Multisync I monitor.  It's a three lead part in a
square package like a volate regulator or power transistor.  The board
is labeled CR691 where the part goes.  (Possibly an SCR?)  The pin
labeled G on the board goes to a zener diode (reference voltage?); the
pin labeled T1 goes to the negative lead of a capacitor in the power
supply, and the pin labeled T2 goes to the negative side of the bridge
rectifier in the supply.

    If anyone can tell me what this is, or better yet, where I can buy
one just like it, please email me at ck3i@andrew.cmu.edu.  I've called
NEC's "monitor repair number" and not only do they not know what the
part is, but they don't think that they can find one to sell to me... 
It makes no sense to me...

Thanks

Newsgroup: sci.electronics
document_id: 54275
From: johng@socrates.umd.edu (John Gustafson)
Subject: Re: solvent for duct-tape adhesive?

ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?

May I tease out a sub-thread from this discussion?

Can you all please tell me how to remove  the stickers from new houses'
appliances and outdoor lampposts?  Especially the lamppost, right on
the glass.  Isn't there something you can rub into stuck-on labels that
will release them from their death-grip on glass or other hard surfaces?

Many thanks for any help.  

                                              John

John Gustafson   johng@socrates.umd.edu


Newsgroup: sci.electronics
document_id: 54276
From: malmedal@ulke.dhmolde.no (Terje Malmedal)
Subject: Ranger2.0 shareware


Hello.

  The last issue of Electronics world describes Ranger 2.0 a PCB CAD program.
According to the article there is a crippled version available as shareware,
does anybody know of any FTP sites/BBSes where this program may be found?

Thanks in advance.
--
 - Terje
malmedal@unix01.dhmolde.no

Newsgroup: sci.electronics
document_id: 54277
From: advax@reg.triumf.ca (A.Daviel)
Subject: Re: How universal are (video) phones these days?

Just saw an article in New Scientist; AT&T videophones won't talk to (?)BTI 
videophones. The AT&T ones use a 19.2kb modem, BTI uses 14.4kb. AT&T models 
have to communicate using all AT&T exchanges, whereas the BTI can route 
via most current exchanges. Suggestions include building standards converters 
into telephone exchanges - the mind boggles :)= . The BTI design is a bit 
more conservative and is better able to cope with current data compression 
hardware on long-distance lines.

(not having the magazine to hand, I may have mis-remembered BTI. I think it
is a British one made by GEC-Marconi, and currently selling to other
countries). 

Yet Another Standards Screw-up.

--
 Andrew Daviel, Vancouver, Canada <advax@triumf.ca>
  finger advax@reg.triumf.ca for PGP key

Newsgroup: sci.electronics
document_id: 54278
From: bsc_graham@vd.seqeb.gov.au
Subject: FM Transmitter ICs- Help!!!!!

I am trying to design a small 90mW 472MHz FM transmitter for remote alarm
use.

Is there an FM transmitter IC available that can be used for this purpose?

Any help, circuits, info etc will be greatfully accepted.

Please reply to bsc_graham@seqeb.gov.au

Thanks in advance.

Graham Castledine.


Newsgroup: sci.electronics
document_id: 54279
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead ACid Batteries Part 2!!!

>The lead-acid secondary cell releases energy (electricity) with the following
>chemical reaction:
> 
>Pb + PbO2 + 2H2SO4 --> 2PbSO4 + 2H20
> 
>Lead and Lead (IV) Oxide and Sulfuric Acid produce Lead Sulfate and Water
[heats of formation deleted]
>The heat of reaction at 25 C is therefore -60.6 kcal per mole PbSO4 produced.
>Note that lead sulfate is not very soluble (0.0048 grams per 100 grams water
>at 25 C), and it will thus precipitate out of solution where the reaction is
>occurring, or the cathode (positive terminal) of the battery.  (I am almost
>sure it is the positive terminal where the precipitate forms, but I may be
>wrong.  Oh well, I don't have a corroded battery to corrobate, and I don't feel
>like thinking through it right now.)

The major problem with this is that the reaction takes place in an ACID solution.
PbSO4 is soluble in an acid solution and will not precipitate out.  Also, H2SO4
is in a water solution as 2H30+ and SO4--.  Thus the heats of formation of
PbSO4 and H2SO4 are for the most part irrelevant.

>What is important to notice here is that the reaction, as you knew it would be,
>is exothermic, or energy discharging.

As it turns out the reaction is indeed exothermic (heat producing).
(More about this later.)

What actually happens to make the battery completely useless is this:
(we're talking lead-acid batteries of course)
The battery slowly self discharges.  As this discharge takes place two things
happen. -The level of Pb++ ions in the acid solution increases (i.e. the lead
           and lead oxide plates are dissolved).
        -The level of H30+ ions in the acid solution decreases (i.e. the solution
           becomes less acidic, or more like water if you like).
Now, as the post to which I am responding correctly stated, PbSO4 will precipitate
in a WATER (non-acid) solution.  When the battery dies (i.e. is fully discharged)
we end up with a high concentration of Pb++ and SO4-- in water.  So PbSO4
forms in the solution and FALLS TO THE BOTTOM OF THE BATTERY (of course this
happens in varying degrees, the more discharged, the more precipitate forms).

The precipitate forms a conductive layer on the bottom of the battery.  If
there is enough of the lead and lead oxide plates left to touch the precipitate
(more common in a newer battery) a dead short results.

I have seen products in automotive shops to correct this condition, but they
are for the most part useless.  They can dissolve the PbSO4 but cannot restore
the lead and lead oxide plates properly.  You may have some success with
these products for a newer battery.

[stuff deleted]
>To understand why lead-acid batteries DO INDEED discharge faster when stored on
>concrete as opposed to wood or earth (dirt), one should recall LeChatelier's
>Principle, which can be paraphrased as:  anything subjected to some stress will
>act to move to a more comfortable position.  Here are the thermal conductivities
>of a some selected materials:
[stuff deleted]
>This is where LeChatelier's principle comes into play.  Removing energy from
>the exothermic reaction will drive the reaction further to completion.  If the
>reaction normally occurs at room temperature, keeping the battery at that
>temperature requires the removal of any heat produced.  A concrete surface is
>a better heat sink than a dirt or wood surface.  Store a battery in the corner
>of a poured concrete basement, and you have 3 surfaces removing energy, which
>"pulls" the reaction along.

This stuff is just made up by the author and is completely invalid.
In fact the discharge reaction takes place at a higher rate at higher
temperatures.  A logical consequence of the above argument is this:
"If you really want your car to start, lower the battery temperature to
 -50 to 'pull' the reaction along."  We all know from experience (at
 least those of us in Canada do (it gets cold up here)) that this is
not true.  If we want to start our car on a really cold day we warm
the battery.

(Besides which, there is not enough energy released through self discharge
 to appreciably raise the temperature.  The air would amply dissipate any
 such heat, whether the bottom of the battery was insulated or not.  This
 is of course irrelevant, since you would WANT the battery to be cool
 during storage.)

Just keep the battery in a cool dry place and keep it charged!


Newsgroup: sci.electronics
document_id: 54280
From: pierson@cimill.enet.dec.com (Dave Pierson)
Subject: Re: PCMCIA

In article <1d.11083.3287.0NAC6CC5@synapse.org>, martin.vuille@synapse.org
(Martin Vuille) writes...

>Does anyone know who to contact to obtain a copy of the PCMCIA standard?

	PCMCIA
	1030G East Duane St
	Sunnyvale, CA 94086 USA
	408-720-0107

	See also:
	alt.periphs.pcmcia

thanks
dave pierson			|the facts, as accurately as i can manage,
Digital Equipment Corporation	|the opinions, my own.
40 Old Bolton Rd		|I am the NRA
Stow, Mass 01775 USA		|pierson@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles

Newsgroup: sci.electronics
document_id: 54281
From: wesw@sr.hp.com (Wes Whiteley)
Subject: Re: solvent for duct-tape adhesive?


I have used a product called "Goof-off" it comes in a little yellow 
can (about the size of a deck of playing cards).

It has worked well for removing all kinds of sticker and tape residues.

NOTE: always test a small area in an inconspicuous place before using.  

Good luck,



Wes Whiteley
(707) 577-5292
wesw@sr.hp.com

Newsgroup: sci.electronics
document_id: 54282
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Pre-fab PC case/power supplies and CSA/UL/FCC stuff

What kind of CSA/UL/FCC approval do $60+ mail-order PC computer
cases and power supplies have?  

Can I assume that the certification process for small-scale custom hardware
(ie digital/analog circuitry) is reduced, or even eliminated, if I use
such a case and (certified) power supply?

Also, assuming that I use a "certified" power supply, have I satisfied the
requirements of CSA/UL approval, and possibly FCC approval as well?
Do mail-order PC cases satisfy FCC certification?  Is FCC certification
even necessary for scientific (non-commercial/non-residential) use?

Newsgroup: sci.electronics
document_id: 54283
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: solvent for duct-tape adhesive?

ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

At least locally, many shops carry a product called Goo Gone.  It works well
on scummy-gummy-sticky-goop-that-won't-go-away...  As always, color test in
an inconspicuous corner before use.

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
document_id: 54284
From: dhollman@phage.cshl.org ( CSHL)
Subject: Re: How to the disks copy protected.

I still think a major point is being missed... If you are worried about
software pirates, NOTHING will stop them. These are people who crack
software (mostly games, but so what) daily for fun. They can usually find
a crack around anything, especially if the manufacturer leaves a hole for such a thing.

-- 
|-----------------------------------------------------------------------------|
|    Are we having fun yet?                                                   |
|-----------------------------------------------------------------------------|

Newsgroup: sci.electronics
document_id: 54285
From: scotts@bbking.FtCollinsCO.NCR.COM ( Scott Sherman)
Subject: Re: Radar/Laser Detectors

In article <GORNISH.93Apr26111045@sp1.csrd.uiuc.edu>, gornish@sp1.csrd.uiuc.edu (Edward H. Gornish) writes:
|> What are people's opinions about laser detectors?  Escort makes a
|> laser detector, the Passport 1000, and claims it works fine.  However,
|> I've talked to some people who have said that it will only work if you
|> are lucky - i.e. if the cop happens to point his laser at a car in
|> front of you, and the laser beam happens to reflect back to your
|> detector.  Otherwise it won't work.  Regular radar, of course, travels
|> in all directions; hence it is more detectable.  Any comments?
|> 
|> Escort has a deal (till the end of April, I think), where if you buy
|> their wideband (Passport 3200 - X, K, Ka) and laser detectors, you'll
|> save $60 off of buying them separately.  In this case, the addition of
|> the laser detector over the Passport 3200 is only $40 (i.e. Passport
|> 1000 normally costs $100).

Uniden makes an all in one unit (X, K, Ka, Laser) for about $130.
Colorado Radar sells passive radar jammers, the passive supposedly being legal,
for about $100. wont help you with Laser however.

Scott

Newsgroup: sci.electronics
document_id: 54286
From: u95_dgold@vaxc.stevens-tech.edu
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu>, johng@socrates.umd.edu (John Gustafson) writes:
> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
> 
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
> 
> May I tease out a sub-thread from this discussion?
> 
> Can you all please tell me how to remove  the stickers from new houses'
> appliances and outdoor lampposts?  Especially the lamppost, right on
> the glass.  Isn't there something you can rub into stuck-on labels that
> will release them from their death-grip on glass or other hard surfaces?
> 
> Many thanks for any help.  
> 
>                                               John
> 
> John Gustafson   johng@socrates.umd.edu
> 

Try WD-40

Newsgroup: sci.electronics
document_id: 54287
From: reid@ucs.indiana.edu (Frank Reid)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu> johng@socrates.umd.edu (John Gustafson) writes:
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
>
>May I tease out a sub-thread from this discussion?
>
>Can you all please tell me how to remove  the stickers from new houses'
>appliances and outdoor lampposts?  Especially the lamppost, right on
>the glass.  Isn't there something you can rub into stuck-on labels that
>will release them from their death-grip on glass or other hard surfaces?

"Petroleum naphtha," available at most hardware stores, will remove most
adhesives.

--

Frank     reid@ucs.indiana.edu

Newsgroup: sci.electronics
document_id: 54288
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does any one know what is the biggest ROM for present ?

         Please replay to : yxy4145@usl.edu
                                  Thanks a lot


Newsgroup: sci.electronics
document_id: 54289
From: gvolk@nyx.cs.du.edu (Greg Volk)
Subject: Re: solvent for duct-tape adhesive?

What I usually use...and this stuff is only good on glass....is either Acetone,
or a little Benzene. The latter of the two is a bit dangerous (possibly a 
carcinogen(sp?)) but it usualy gets the job done. I imagine you can you the two
solvents on most metals as well as glass, but keep the stuff away from plastic.
Better yet, you may just want to go to your local hardware store and ask them
what they use. 

Newsgroup: sci.electronics
document_id: 54290
From: eldred@rrunner.jpl.nasa.gov (Dan Eldred)
Subject: Re: solvent for duct-tape adhesive?

In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?
>Someone taped wires to the carpet, and now it is time to move out.
>
I don't know for sure that this will work, but you might try MEK (methyl
ethyl keytone?).  It worked getting the stickum left over from shelf paper,
and is available at paint stores.  Use a carbon gas mask and lots of
ventilation--this stuff really stinks!

	- Dan


Newsgroup: sci.electronics
document_id: 54291
From: mxmora@unix.sri.com (Matt Mora)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu> johng@socrates.umd.edu (John Gustafson) writes:
>ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?


I use WD-40.


>May I tease out a sub-thread from this discussion?

>Can you all please tell me how to remove  the stickers from new houses'
>appliances and outdoor lampposts?  Especially the lamppost, right on
>the glass.  Isn't there something you can rub into stuck-on labels that
>will release them from their death-grip on glass or other hard surfaces?

>Many thanks for any help.  


Try WD-40.





Xavier







-- 
___________________________________________________________
Matthew Xavier Mora                    Matt_Mora@qm.sri.com
SRI International                       mxmora@unix.sri.com
333 Ravenswood Ave                    Menlo Park, CA. 94025

Newsgroup: sci.electronics
document_id: 54292
From: mxmora@unix.sri.com (Matt Mora)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

In article <1993Apr25.223611.1@auvax1.adelphi.edu> schmidt@auvax1.adelphi.edu writes:

>platen, etc flew across the room, and several people in the room almost had
>heart attacks.  Beware the explosive properties of WD40 vapor.
>


We use it as starting fluid for jet ski's. The fact that its a lubricant 
works very well since jet ski's are 2 cycle. It also helps when a ski
floods with water because we clean the spark plus with the stuff.


OB sci.electronics:


I have an office/studio in my garage with a phone in it. Our wireless phone
has a page feature where you can make the phone or hand set ring to get
the attention of the other person. Is there a simple circuit that I can use
over the second pair of wires (or the first pair) to emulate this effect
with the phone in the garage? (ie push a button to make the phone ring in the
house or push a button to make it ring in the garage.)



Thanks


Xavier
 
-- 
___________________________________________________________
Matthew Xavier Mora                    Matt_Mora@qm.sri.com
SRI International                       mxmora@unix.sri.com
333 Ravenswood Ave                    Menlo Park, CA. 94025

Newsgroup: sci.electronics
document_id: 54293
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: 8x oversampling CD player

In article <mcmahanC5v942.MKJ@netcom.com> mcmahan@netcom.com (Dave Mc Mahan) writes:
> In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>>
>>>I just bought a new portable CD player for the office, and I notice that
>>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box. 

>>The data is only ever read once (barring mistracks and such, of course),
>>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>>Oversampling takes two discrete data points, and interpolates n-1 points
>>between them for n times oversampling.  When I asked, people said that the
>>interpolation was not simply linear interpolation, but significantly more
>>complicated.

>You are quite correct in your understanding.

>In case you care, the filtering method uses an FIR (finite impulse response)
>filter.  I'd guess that CD makers use the same kind of method.  Anybody out
>there know the real answer? 

	Typical (in the old 2x-oversampling units) was a thirteen-tap
FIR, implemented as a dedicated hardware addition circuit.  At this kind
of speed (slow, by digital standards) such an adder is much less
expensive than analog components of comparable precision.

	I gleaned this information from a hardware manual for
an old CD player design; where one would find similar info for
a particular CD (the digital filter IS an interesting component,
from my point of view), I have no idea.  The digital filter
is a kind of interpolation scheme (read a book on numerical 
analysis, to see just how BROAD the term 'interpolation' is...),


	John Whitmore



Newsgroup: sci.electronics
document_id: 54294
From: michael@chpc.utexas.edu (Michael Lemke)
Subject: Re: How universal are phones these days?

In article <26APR199315293014@utkvx.utk.edu> iturriag@utkvx.utk.edu (Mr. Y) writes:
[...]
>
>I am not quite so sure about the illegality of using a regular American phone
>on your home system. I vaguely remember a few years ago, when "Deutsche
>Bundespost" split into Postdienst, Postbank, and Telekom there was some
>discussion about a new regulation. I know that cordless or cellular phones
>still have to be approved by the Telekom, but does that hold true for regular
>phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use
>touch-tone dialing. I assume, however, that most areas are still exclusively
>set to pulse dialing. Last time I checked (Jan '93) the Cologne areacode 221
>was still solely pulse dialing.
>
>BTW, touch tone does become more common in Germany, bringin with it the
>flourishing of 1-900 services (in Germany 0190). I just hope we'll all have
>ISDN some time at an affordable price - idle wishes...
>

Does this imply the German tone dialing is compatible with the American 
one?  I know at least the British system is not -- it is supposedly close 
enough though that an American phone will work.  But my modem (American)
has a special setting for British standards...

Michael
-- 
Michael Lemke
Astronomy, UT Austin, Texas
(michael@io.as.utexas.edu or UTSPAN::UTADNX::IO::MICHAEL [SPAN])

Newsgroup: sci.electronics
document_id: 54295
From: flux@inqmind.bison.mb.ca (John Kamchen)
Subject: VGA circuit

I've come across a circuit from Integrated Circuit Systems Inc
called a GSP500.   This chip genlocks a VGA card to a dual input
NTSC signal.  
The output from this chip is basicly a pixel clock, and has various 
speeds.  I notice that it outputs a 28mhz clock..  can this output be 
used on an Amiga system?
And must it be NTSC/VGA  or can it be NTSC/NTSC  ?
 
Any simple circuits to boost an NTSC to a VGA signal?
Need to genlock a laser disc to my 31khz video.
-John


flux@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
document_id: 54296
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: FREE! EPROM eraser/PCB exposer(Twin cities collect)

This inelegant device started life as a 175 watt security lamp, until
i smashed off the outer glass to liberate the nasty rays, It works a
treat, weighs a heap (due to the ballast) , and NO - i wont ship it !!
cheers
Mike.

Newsgroup: sci.electronics
document_id: 54297
From: wa2ise@netcom.com (Robert Casey)
Subject: Re: Cable TVI interference

If I remember rightly, there is a pulsating set of tones piped thru the CATV
systems (somewheres near the FM broadcast band).  And that the cable company
trucks listen for this as they roam around town.  If you can hear it over
the air and not cable....

Newsgroup: sci.electronics
document_id: 54298
From: nilesh@shakti.ncst.ernet.in (Nilesh Parikh)
Subject: HELP : Wanted Pinouts of OKI 58321, RTC

Can anybody send me Pinouts of Real Time Clock IC of OKI Semiconductors,
58321. I wish to know if any RTC IC of OKI has an inbuilt crystal rather
than an external 32.768KHz crystal.
Thanks in advance.
Nilesh Parikh
nilesh@shakti.ncst.ernet.in


Newsgroup: sci.electronics
document_id: 54299
From: blockley@csu.murdoch.edu.au (Adrian Blockley)
Subject: Programming Motorola XC68HC705P9?

Has anyone successfully programmed this beast using the bootloader pgm
with the circuit described in `the little green handbook, pg 9-1`?

Dan.
--

----------------------------------------------------------------------
Adrian Blockley                    ! I may say something profound   
Environmental science              ! here one day.                  
Murdoch University                 !                          
Western Australia, 6153            !                               
blockley@essun1.murdoch.edu.au     !                                
phone 09-360 2737                  !
----------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54300
From: lc@goanna.cs.rmit.oz.au (leon)
Subject: Re: 2% silver solder

In article <199304251131.AA08572@dec3100a> shiekh@ictp.trieste.it (Andy Shiekh) writes:
>
>  I have seen the existance of electronics solder with a 2% silver
>content that seems to have good wetting and fatique reatings.
>  Can anyone tell me why it is not used? (silver is not such an expensive
>metal).
>
From "Management of Electronics Assembly" (Ian Oakes)
After talking about 63/37 tin lead alloy and the eutectic point...
"Occasionally, impurities may be added to solder, to vary charactersitics 
within the soldering process in an attempt to improve performance.  For
example, addition of small quantities of antimony and copper can reduce
the amount solder moves under stress when solid.  For particular
applications additions of impurities may be warranted but, in general, it
is best to keep the solder used in a soldering process as pure as possible."

I guess this is the good oil for commercial operations, but it doesn't
mention anything esoteric.

leon


Newsgroup: sci.electronics
document_id: 54301
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: solvent for duct-tape adhesive?

From article <1993Apr27.004240.24401@csi.jpl.nasa.gov>, by eldred@rrunner.jpl.nasa.gov (Dan Eldred):
> In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
>>Someone taped wires to the carpet, and now it is time to move out.
>>
> I don't know for sure that this will work, but you might try MEK (methyl
> ethyl keytone?).  It worked getting the stickum left over from shelf paper,
> and is available at paint stores.  Use a carbon gas mask and lots of
> ventilation--this stuff really stinks!
> 
> 	- Dan
> 

For those who don't know, methyl ethyl ketone is more commonly known 
as ACETONE and can be found as the major active ingredient in
NAIL POLISH REMOVER.  YOUR WIFE'S PROBABLY GOT SOME HANGIN' AROUND....

Newsgroup: sci.electronics
document_id: 54302
From: erickson@azure.nmt.edu (Alan Erickson)
Subject: PC parallel I (!= I/O)

	I'm trying to bring in 8+ bits to a PC, and would like
	to use interrupt-driven routines. Without buying an IO
	board or making a new port, _where_ can I bring in these
	bits? LPT seems to have only a few inputs, but I've heard
	rumours that some LPTs have bidirectional lines. Anybody
	know fer sure? If any bi-d LPTs, which boards have them
	(I'll be running a new 386DX-33)?

------------------------------------------------------------------
Alan Erickson   erickson@baltic.nmt.edu		

to all SunRayce '93 competitors: I hope you're getting
about as much sleep as I am.....
------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54303
From: jimt@ee.mu.OZ.AU (Jim Trivellas)
Subject: * HELP needed with LIGHT DEPENDENT RESISTOR Devices (LDRs) *

Can some kind soul provide me with information on LDRs that contain an
onboard light-source, in a totally integrated and light-shielded unit.

I have seen a VTL5C LDR in some schematics.  So who are the manufacturers
of these devices, and what are the different types.

Thanks very much in advance,
Jim.

-------------------------------------------------------------------------------
  Jim Trivellas.
  Department of Electrical & Electronic Engineering.
  School of Information Technology & Electrical Engineering.
  The University of Melbourne, Parkville 3052, Victoria, Australia.
                  |
                  |
                  |			Telephone: +61 3 3447976
                *****			Email: jimt@mullian.ee.mu.oz.au
     _______*************_______
   _|_____*****************_____|_
 _|_|_____*****************_____|_|_	"Hello, is that the front desk?"
| | ________*************________ | |			Allan Holdsworth
|  |            *****            |  |
   |          The  SPID          |
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54304
From: jtsilla@damon.ccs.northeastern.edu (James Tsillas)
Subject: Re: How universal are phones these days?


I sent a 2400 baud modem to a cousin in Greece from the U.S. and it is
working fine for him. It also worked for me in U.S.

-Jim.

--
	***  James Tsillas  jtsilla@damon.ccs.northeastern.edu   ***
	***      Work: (508)898-2800, Home: (617)641-0513        ***
	***        "He is after me. Jim is after him."           ***
	***            - Hop on Pop, Dr. Seuss                   ***

Newsgroup: sci.electronics
document_id: 54305
From: mpoly@panix.com (Michael S. Polymenakos)
Subject: Re: How universal are phones these days?

In <LHE.93Apr26131014@yang.sics.se> lhe@sics.se (Lars-Henrik Eriksson) writes:

>Most (if not virtually all) swedish exchanges can handle tone
>dialling. Many older electromechanical exchanges have been modified
>accept tone dialling.

 I would not be suprised if the equipment is compatible, in fact New York
Telephone (NYNEX) spend a lot of money on Swedish switching equipment
recently.

>Lars-Henrik Eriksson                            Internet: lhe@sics.se

 You can guess what brand of equipment I refer to :-)

Michael
-- 
______________________________________________________________________________
             In this land, said the god; "who seeks shall find; 
        Who sits with folded hands or sleeps is blind." - Sophocles

Newsgroup: sci.electronics
document_id: 54306
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

I wrote:

: : bit of it, you could take the tape over to a local ham operator's house
: : and ask him for his opinion of what you're hearing.  Most communities
: 
: You cannot do that legally. However, you can ask a ham over to listen.
: If the interference occurs at a specific time each day, then it would
: be possible to do such scheduling.  If nothing else, you could invite
: the ham over to transmit from your driveway, to see if he interferes.
: If he does, then you probably need to have your equipment worked on to
: make it immune to rf interference.

As a coupld of people have pointed out - this is wrong. It is not illegal
to record or disclose what you heard on the Ham bands. 

Bill

Newsgroup: sci.electronics
document_id: 54307
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

galen@picea.CFNR.ColoState.EDU (Galen Watts) writes:
: 
: Why can't he record it legally?  It may not be admissable in court, but
: recording for personal use is legal.  If he wants to play it for his ham
: friend, that's legal too, as long as he doesn't charge admission.

Yeah - I goofed - a slip of the mind. I must be getting senile.

... deleted ...

: Hey Bill, where were you three weeks ago when all this stuff was posted
: and dealt with?

Busy posting on about 20 other groups. I get to this one about once every
three months or so. 

Bill

Newsgroup: sci.electronics
document_id: 54308
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <1993Apr24.064907.22281@ennews.eas.asu.edu>, gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan) writes...

>I designed and built hardware in 1988 that would output a logic level (from
>a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
>Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
>variations in sunlight (and 60Hz from lights). Used no lenses.
> 
>Allen Sullivan

I would be interested in knowing more about the sensing hardware.  What did
you use for the detector?  Could you detect the angle of location, or did
the system simply respond to the presence of the transmitter in the sensors
field of view?

Newsgroup: sci.electronics
document_id: 54309
From: tsar.Princeton.EDU!fuchs (Ira H. Fuchs)
Subject: Re: Removing battery corrosion

In article <1993Apr26.165902.239@uvm.edu> me170pjd@emba-news.uvm.edu.UUCP  
(Peter J Demko) writes:
> From article <1993Apr25.201129.1239@Princeton.EDU>, by  
fuchs@tsar.princeton.edu (Ira H. Fuchs):
> > Is there a readily available solvent that does a good job at removing  
the  
> > corrosion/encrustation that collects on the battery terminals (usually  
the  
> > cathode) when using alkaline batteries (or more accurately, when NOT  
using  
> > them for a long time)? 
>  generally,  the corrosion is a signal that it's time to send them
>  of to the recyclers, but if you're that desperate or cheap try 
> baking soda and a wire brush. use gloves and goggles, please!

Sorry, I meant the terminals in the device not on the batteries (which are  
obviously quite dead).

Newsgroup: sci.electronics
document_id: 54310
From: ynecgan@sx.mont.nec.com (Greg Neill)
Subject: Wanted: source for tuning capacitors


Hello there.  The other day I was feeling a tad nostalgic and thought
about constructing an old-time crytal radio set.  I figured on
substituting a modern germanium diode for the crystal, and winding the
antenna coil, etc., myself.

The only problem I seem to have is in locating a source for a tuning
capacitor -- you know, the old meshed-plate variable condensers which
used to be the mainstay for tuning circuits.  Well these things seem to
be all but extinct in their original catalog habitats.  Trimmer
capacitors are relatively abundant, but are not really suitable for this
application.

So, can anyone point me to a supplier of tuning capacitors in the 
0--360 pF range?

Manythanks.

-- 
------------------------------------------------------------------------------
Greg Neill,               | ounce (ouns), n. - The standard unit of
HNSX Supercomputers   Inc.|   prevention, equal to one pound of cure.
gneill@cid.aes.doe.ca     | 

Newsgroup: sci.electronics
document_id: 54311
From: u9035710@wraith.cs.uow.edu.au (Scott Anthony Barnett)
Subject: Filter Design Software for IBM-PC

Has anyone got an active filter design program that runs on an IBM PC ??

Something that will easily let me specify bandpass filter parameters,
and it will give me the appropriate component values ??

It has to be public domain,  if anyone has one, could you mail it to me.

Thanks in advance,

Scott
u9035710@wraith.cs.uow.edu.au

P.S. It can run under windows if necessary.



Newsgroup: sci.electronics
document_id: 54312
From: swanee@megadata.mega.oz.au (Geoff Swan)
Subject: Re: Why circuit boards are green?

In article <1993Apr23.102039.1720@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
> 
> The color of the board shows the composition of it, hence the use of it.
> 
> Original and older boards were bakelite composition, and were brown.
> Phenolic (spelling) was a tan
> Most "non filled" fiberglass boards used in computers are green.
> Filled fiberglass is blue.
> Teflon is white.
> 

Rubbish. The reason for the colour of the boards depends on the solder
mask that is used. Older boards (bakelite and phenolic) rarely used
a solder mask (these boards are not suited well to automatic stuffing
and soldering techniques) and hence are the colour of the compound
used to make them. These days boards are made of fibreglass for most
general purpose uses and have a solder mask applied to them to prevent
close traces shorting to one another during soldering (and also to prevent
the decomposition of traces under harsh environments). The light and dark
green boards ofter seen have a "dry film" mask applied to them (usually
applied as a complete film photographically produced). The blue (and red
or orange) boards are a two-part epoxy or a liquid-imageable resist
formulation and are applied in a different manner. There's a lot of info
about the pro's and con's of each, but that's another story...

    Sla/n go fo/ill,
                    Risky B.
--------------------------------------------------------------------------
Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
Megadata Pty Ltd                     /      \ 
2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
NSW 2113, Australia.                       v          (Fax) +61 2 887 4847




Newsgroup: sci.electronics
document_id: 54313
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Re: PC parallel I (!= I/O)

erickson@azure.nmt.edu (Alan Erickson) writes:

> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?

 
        Yes, it is possible.  I'm making a 7 stepper controller board, 
with 7 digital inputs, and (up to) 18 digital outputs from the // port.
   One main thing that will tell you whether the // port is 
bi-directional or not is the bus tranceiver on it.  Look for a chip 
numbered 74LS245.  If you don't have this, then it's probably a 74LS244, 
which will do you NO good for reading in.
  
          Now, if you do have the '245 then do the following:
  First, find the address of the port, (decimal) either 888, or 632.
  In pascal, you would "Write(Port[xxx]);" where xxx is the address in 
either hex or decimal.  The status lines, pins 14, 16, 17, as well as the 
strobe, pin 1, are bi-directional lines, and are read by base address +2, 
so for 888, to read from status, then read from 890.  You can also output 
to these lines in the same fashion as to the data lines.  In pascal, 
do "Port[xxx]:=value
".
 
                Hope this helps.
        Let me know if you need more help.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
document_id: 54314
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: ___Fax Machine scanners to mono-computer scanners?

 
        I was wondering, since I've got a few fax machine scanners 
intact, if they could be integrated to the pc environment as a 
mono-scanner?  If so, where to start?!
 
                Thanks.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
document_id: 54315
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: ^^ Phosphorescent pads ...

 
         A while ago I saw some translucent pads, about 6"x8" or so that 
could be plugged into (something) and they would glow.  One was red, 
another green, another blue.  Interresting.  I was wondering if anyone 
would have a feed on anything of this nature, and of the price.
   oh, the pads were rubber-like and were floppy like, about 1cm thick or 
so.
 
                Thanks.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
document_id: 54316
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Wanting 3479P's...

 
        If anyone would have a low quantity distributer for these little 
beasts (3479P) by Motorola, please let me know!
 
_______________________________________________    
             |                                 |
   _______   |    Baden de Bari                |
  /       \  |     baden@sys6626.bison.mb.ca   |
 (| o   o |) |     baden@inqmind.bison.mb.ca   |
  |   ^   |  | >> True life can only           |
  \  -=-  /  | >> be experianced by            |
   \_____/   | >> those who do not fear death. |
-----------------------------------------------


Newsgroup: sci.electronics
document_id: 54317
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.235820.10742@mnemosyne.cs.du.edu> gvolk@nyx.cs.du.edu (Greg Volk) writes:
>What I usually use...and this stuff is only good on glass....is either Acetone,
>or a little Benzene. The latter of the two is a bit dangerous (possibly a 
                                                ^^^^^^^^^^^^^^^  ^^^^^
>carcinogen(sp?)) but it usualy gets the job done. I imagine you can you the two
  ^^^^^^^^
>solvents on most metals as well as glass, but keep the stuff away from plastic.

Benzene is most definitely a carcinogen. If you can get your hands on it

* Don't use it! *

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
document_id: 54318
From: neilson@pmin28.osf.org (Peter Neilson)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr27.030226.16016@uvm.edu> me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko) writes:
>From article <1993Apr27.004240.24401@csi.jpl.nasa.gov>, by eldred@rrunner.jpl.nasa.gov (Dan Eldred):
>> In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>>>I know this is a long shot, but does anyone know what solvent I should 
>>>use to clean duct-tape adhesive from carpet?
>>>Someone taped wires to the carpet, and now it is time to move out.
>>>
>> I don't know for sure that this will work, but you might try MEK (methyl
>> ethyl keytone?).  It worked getting the stickum left over from shelf paper,
>> and is available at paint stores.  Use a carbon gas mask and lots of
>> ventilation--this stuff really stinks!
>> 
>> 	- Dan
>> 
>
>For those who don't know, methyl ethyl ketone is more commonly known 
>as ACETONE and can be found as the major active ingredient in
>NAIL POLISH REMOVER.  YOUR WIFE'S PROBABLY GOT SOME HANGIN' AROUND....

Oh dear, time for me to try to remember my chemistry.  Let's see if I
can find the formulae somewhere in the dim recesses of my mind.
<sounds of gears>  <fumes of overheated oil>  <unmistakable stench of
the Nasal Chromatograph>   Ha!  I knew there was a double bond!  Now
how shall I show that in ASCII? 

          MEK:                                 Acetone:

          C - C - C - C                        C - C - C
              #                                    #
              O                                    O

The hydrogens are not shown, and # represents double bond.  MEK has a
methyl (CH3) on one side, and an ethyl (C2H5) on the other.  Acetone
has two methyls.  So acetone is not methyl ethyl ketone, but instead
is dimethyl ketone.  Both solvents have similar properties.  I think
that MEK may be a little less flammable but a lot worse to breathe.
It's a lot harder to buy MEK than it once was.  Use acetone.

Nail polish remover consists almost entirely of acetone.  If you buy
some for your workshop, get the very cheapest, because the more
expensive kind has oils and perfumes that you don't need.
-- 
Nothing is so foolish that it has not been posted to some net newsgroup.
         >>> Peter Neilson --- neilson@osf.org <<<
Quote changed daily.  If you've seen this one before, burn your calendar.

Newsgroup: sci.electronics
document_id: 54319
From: ba1926108@ntuvax.ntu.ac.sg (AaronAw)
Subject: Card Phones

Can you help me to understand how a CardPhone operates and 
how the values are stored on the phonecard..

Thanx


Newsgroup: sci.electronics
document_id: 54320
From: d9bertil@dtek.chalmers.se (Bertil Jonell)
Subject: Re: How universal are phones these days?

In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
>There is a wire without any jack at the end sticking out of the wall. So you
>need to connect the wires (I'm not sure if they have wall jacks in Western
>Europe - they may).

  Son of the Return of the "How much does Americans know about the rest of
the word?"-flamewar anyone?

-bertil-
--
"It can be shown that for any nutty theory, beyond-the-fringe political view or
 strange religion there exists a proponent on the Net. The proof is left as an
 exercise for your kill-file."

Newsgroup: sci.electronics
document_id: 54321
From: fedup@firga.sun.ac.za (FE DU PLESSIS [M.ING E&E])
Subject: Re: References for ANY IC

 In a previous article, ree88132@zach.fit.edu (Keith Ledig) writes:
>I am looking for a text/reference that will include pinouts, 
>description, and functionality for just about any IC made.
...

You can find cross reference to almost any IC or discrete semiconductor in 
Philips ECG: Semiconductors Master Replacement Guide, ~$10. (Especially 
industrial, commercial and entertainment, but not specialised or military.)

 - Francois

Newsgroup: sci.electronics
document_id: 54322
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - SunConnect ICNC)
Subject: Re: How universal are phones these days?

In article <C651xu.Gwq@news.chalmers.se>, d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
> In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
> >There is a wire without any jack at the end sticking out of the wall. So you
> >need to connect the wires (I'm not sure if they have wall jacks in Western
> >Europe - they may).
> 
>   Son of the Return of the "How much does Americans know about the rest of
> the word?"-flamewar anyone?


We're doing that one in s.c.british at the moment...





Newsgroup: sci.electronics
document_id: 54323
From: harris@athena.mit.edu (Jonathan G Harris)
Subject: Re: solvent for duct-tape adhesive?

>>> On benzene and acetone.
Not only is benzene a carcinogen, it is adsorbed through the skin and cause
cumulative damage to the bone marrow which is essential to the production of
your blood cells.  It is highly toxic. One exposure is unlikely to kill you,
but it will likely do hidden damage.  Benzene is one compound that chemists
try like hell to avoid using!
Acetone is much less toxic, but is highly flammable and volatile. 
It also dissolves lots of things so handle with great care!
-- 
Jonathan G. Harris
Department of Chemical Engineering,  MIT Rm 66-450 
25 Ames Street, Cambridge, MA 02139
harris@athena.mit.edu (617)253-5273  Fax 253-9695

Newsgroup: sci.electronics
document_id: 54324
From: rbhurtha@cs1.uct.ac.za (R BHURTHA)
Subject: HD-TV SOUND SYSTEMS

I would like to get some information on the current systems used for HD-TV
sound systems.thanks.

Newsgroup: sci.electronics
document_id: 54325
From: jmichael@vnet.IBM.COM
Subject: Re: solvent for duct-tape adhesive

Acetone will likely damage the carpet. First solvent to try is denatured
alcohol. Do not waste your time with rubbing alcohol. You can use methyl
alcohol instead of denatured alcohol. If you want to have a cocktail while
you are removing the goo, use pure grain alcohol :-). If the alcohol does
not work try carbon tetrachloride. If neither of these work you may need to
try a stronger solvent, but the alcohol works for most adhesives. Good luck.

Jim

Newsgroup: sci.electronics
document_id: 54326
From: lan_kova@rcvie.co.at (Tom Kovar)
Subject: Re: How universal are phones these days?

d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
: In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
: >There is a wire without any jack at the end sticking out of the wall. So you
: >need to connect the wires (I'm not sure if they have wall jacks in Western
: >Europe - they may).
: 
:   Son of the Return of the "How much does Americans know about the rest of
: the word?"-flamewar anyone?

  Well, Bertil, you might laugh, but in many places here in Austria, there are
no wall jacks yet, either - just wires sticking out of the wall (and put into
a closed, often sealed, box) :-)
  As far as I remember from Germany, it is a nicely mixed situation - somebody
had wires sticking, somebody had jacks...
  On the other hand, everywhere in Bohemia I have seen wall jacks, and never
seen just wires sticking out of the wall... And I thought Slovakia was the
same case. Well...

  "How much do Scandinavians know about the rest of Europe?? :-))"

							Tom
-- 

       ___  /   ___  /   ____/    Tomas Kovar
      /    /   /    /   /         Alcatel Austria Forschungszentrum G.m.b.H.
     ___  /   ___  /   __/        A-1210 Wien, Ruthnergasse 1-7
    /    /   /    /   /           Tel: +431-391621-283 Fax: +431-391452
 __/  __/ __/  __/ __/            E-Mail: Tom.Kovar@rcvie.co.at                               

Newsgroup: sci.electronics
document_id: 54327
From: pvr@wang.com ()
Subject: Re: 2% silver solder

shiekh@ictp.trieste.it (Andy Shiekh) writes:

>  I have seen the existance of electronics solder with a 2% silver
>content that seems to have good wetting and fatique reatings.
>  Can anyone tell me why it is not used? (silver is not such an expensive
>metal).

   This is called silver bearing solder.   It is used to solder to
devices that have silvered contacts.   One application is soldering
to the ceramic terminal strips used in the old Tektronix scopes.   These
were notched ceramic strips that were silver plated in the notches.
If you used ordinary solder the molten metal would disolve the silver
off of the ceramic.   The silver was quite thin.   The 2% is a saturated
solution of silver in tin and lead.    Thus, no more silver can be
disolved in the solder solution.   Other devices that use silver contacts
are quartz crystals and ultrasonic transducers.
--
-->>>>>>>>>> Peter Reilley ..... pvr@wiis.wang.com ..... KA1LAT <<<<<<<<<<<--
     For info on BEAV (Binary Editor And Viewer) finger pvr@das.wang.com
                     Well, that about says it.

Newsgroup: sci.electronics
document_id: 54328
From: wwerner@thor.mlb.semi.harris.com (William S. Werner)
Subject: Correction to Harris's AnswerFAX Phone Number

     ====================================================
       H    H      A      RRRRR    RRRRR   IIIII  SSSS
       H    H     A A     R    R   R    R    I   S    
       HHHHHH    AAAAA    RRRRR    RRRRR     I    SSSS
       H    H   A     A   R    R   R    R    I        S 
       H    H  A       A  R     R  R     R IIIII  SSSS  
     ====================================================


Harris Semiconductor now has AnswerFAX. AnswerFAX is on-line 24 hours
a day, 7 days a week, so you can instantly receive datasheets and 
application notes by using your touch-tone telephone and FAX machine.
The number to call is (407) 724-3818. (It is not set up to do international
calls at this time.)

The general decision tree for the AnswerFAX is as follows, the numbers are
the available selections:


       Welcome to Harris Semiconductors AnswerFAX
                           |
        ----------------------------------------
        |                                      |
        1                                      2
        |                                      |
 Select 1 if you                        Select 2 for an
 are familiar with                      explanation of
 AnswerFAX.                             AnswerFAX
        |                                      |
        |--------------------------------------|
                           |
                           |                              
                           |
            --------------------------------
            |                              |
            1                              2
            |                              |
     Select 1 to order              Select 2 for a
     a document (the                list of catalogs:
     document list is                  1  New Products
     in the catalogs,                  2  Linear Products
     get them first)                   3  Data Acquisition Products
            |                          4  Digital Signal Processing Products
            |                          5  Discrete Power and Intelligent
            |                             Power Products
            |                          9  Application Notes
            |                              |
            |                              |
  Select appropriate document    Select Appropriate Catalog
            |                              |
            |                              |
  Do you want to order           Do you want to order
  anything else? If yes,         anything else? If yes,
  you will be taken back         you will be taken back 
  to the selection decision.     to the selection decision.
            |                              |
            |                              |
            --------------------------------
                          |
                          |
                          |
                  What is phone number
                    for your FAX?
                          |
                          |
                  What is your name?
               (request the instructions)
                          |
                          |
                         END                        



Bill Werner


===========================================================================
Bill Werner           WWERNER@hsscam.mis.semi.harris.com
Harris Semiconductor  wwerner@thor.mlb.semi.harris.com
Melbourne Florida     "....life is but a candle, and a 
(407)729-5515         dream will give it flame..." - Rush, Caress of Steel
===========================================================================
 


Newsgroup: sci.electronics
document_id: 54329
From: iisakkil@beta.hut.fi (Mika Iisakkila)
Subject: Re: How universal are phones these days?

d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
>  Son of the Return of the "How much does Americans know about the rest of
>the word?"-flamewar anyone?

Let's save some bandwidth, skip the intermediate articles and go
straight to the Nazis and Hitler :-)

(we do have wall sockets, thank you, and they're better than yours)
--
Segmented Memory Helps Structure Software

Newsgroup: sci.electronics
document_id: 54330
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: How to the disks copy protected.

In article <1ra4hrINN3ni@DOLPHIN.ZOO.CS.YALE.EDU> stone-andy@cs.yale.edu (Andy Stone) writes:
>Subject: Re: How to the disks copy protected.
>	I wrote a commercial program called GAME-MAKER (can you guess what
>it does).  What we do is have a document protect (answer Question on page x, 
>line y), which is a real pain.  We also allow the user to register by sending
>in a card, and computing a # based on their name.  The system works in that
>we've gotten lots of registration cards.
>	I hear that the program has been cracked though.  Someone two people 
>actually called up my support--one with a question, the other wanting to
>buy our graphics libraries (right!).  Anyway if anyone wants to help me
>catch a cracker and has the cracked version, mail me.  I won't accuse
>you (unless you're the cracker of course).
>

I know of at least one ftp-site from which you can download the cracks of
about any commercial game in existence. The names of the companies (yes,
companies!) are also blatantly advertised with the crack codes. According to
them, it is not illegal (at least in the USA, according to a statute or 
something) to remove the copy protection from any program. The only condition
is that you may only use this code on legally owned software for your own
convenience.

If there is any interest I will download the advertisement of one such 
company. I will not give the name of this ftp-site to anyone, even if only
to protect the companies which wrote the original games.

DISCLAIMER: I do not condone the use or cracking of any programs. I believe 
it hurts the industry and individuals in the long run.

On the subject of copy protection: Most pirates don't give a damn about 
using software on which the name of the registered owner came up on starting 
the program. They just don't have a conscience.

- gerrit

Newsgroup: sci.electronics
document_id: 54331
Subject: Re: FM Transmitter ICs- Help!!!!!
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1993Apr27.080115.22046@vd.seqeb.gov.au>  writes:
> I am trying to design a small 90mW 472MHz FM transmitter for remote alarm
> use.
> 

Pretty high frequency for one chip...

> Is there an FM transmitter IC available that can be used for this purpose?
> 
> Any help, circuits, info etc will be greatfully accepted.
> 
> Please reply to bsc_graham@seqeb.gov.au
> 

Yes and no. I would use the FM transmitter chip from Motorola (Linear and  
Interface Databook), a stable cristal oscillator and a mixer (e.g. SBL-1 from  
mini circuits lab). Everything is done in the FM chip and then mixed up with  
the oscillator frequency. Just have a look at the ARRL Handbook. There are lots  
of ideas in there about oscillators and mixing. I don't think, there are single  
chip designs for such high frequencies yet.

> Thanks in advance.
> 
> Graham Castledine.

Cheers   Robert HB9NBY
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
document_id: 54332
From: pguello@uwsuper.edu (Paul Guello)
Subject: Re: solvent for duck tape adhesive

If you want to try a non-toxic solvent, there's one made of citrus that 
works very well and doesn't take your skin off in the process.  One brand 
name I've used is Citra-Solve, but there are others too.

Newsgroup: sci.electronics
document_id: 54333
From: v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Looking for a good book on Pspice 5.2


	I just got a copy of spice 5.2. I would like to know if there are
any published books on the market yet and where I could get one. I would
appreciate any help. Thank You

		Neil Gandler

Newsgroup: sci.electronics
document_id: 54334
From: pmanson@bnr.ca (Peter Manson)
Subject: Re: solvent for duct-tape adhesive?

In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?

Yet another suggestion, but this one is non-toxic (although I would handle
it like any other cleaner) and it smells nice.  The chemical is called
d-Limonene, and it smells like lemon peels (I think it is a lemon extract
of some kind).  You might find it in a hardware store, sold as a
general-purpose solvent, but your best bet would be any bike store --
it is used as a chain-cleaning fluid.  It works on sticker glue, crayons,
grease, oil, etc.

It's clear yellow in the bottle, and you can use it straight; if you add
water, it changes to a creamy consistency, which is good for some jobs.

Peter

Newsgroup: sci.electronics
document_id: 54335
From: deaddio@ski.bellcore.com (Michael DeAddio)
Subject: Acceleration sensor?

Does anyone know of any type of acceleration sensor that has
an electrical output of any sort?  It would only have to sense
acceleration in one direction.

Thanx,

Mike

-- 

________________________________________________________
Michael DeAddio (MTS)         | Work hard, play hard, 
Bell Communication Research   | the only problem is that 
deaddio@thumper.bellcore.com  | playing hard makes 
201-829-5024                  | working harder.
MRE 2Q-260                    | 

Newsgroup: sci.electronics
document_id: 54336
From: inelson@gopher.cc.ucf.edu (Ian Nelson - I&R IBM Consultant)
Subject: Old schematics

Wonder if anyone would know where (or if) I could find the schematic for the 
old Timex-sinclare (sp) computer... Or even a pin out on the expansion bus??

					Thanks in advance..
					Ian Nelson
					(inelson@ucf1vm.cc.ucf.edu)

Newsgroup: sci.electronics
document_id: 54337
From: mcole@spock (COLE)
Subject: Disk drive read & write

I am working on a project and am in need of information regarding the  
currents (at the head) needed to write to a hard drive and the currents  
produced when reading.  If anyone has information it would be much  
appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
document_id: 54338
From: DPierce@world.std.com (Richard D Pierce)
Subject: Re: Acceleration sensor?

In article <1993Apr27.145201.15495@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.

Gee, how about an (ahem) "accelerometer"! Such devices are available from
a variety of sources (one that comes to mind is Bruel & Kjaer if you have
a lot of money to spend). MOst of these sorts of devices output a voltage
proportional to acceleration. You need to know what range you're talking
about though.


-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |

Newsgroup: sci.electronics
document_id: 54339
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: solvent for duct-tape adhesive

In article <19930427.060713.357@almaden.ibm.com>, jmichael@vnet.IBM.COM writes:
|> From: jmichael@vnet.IBM.COM
|> Date: Tue, 27 Apr 93 09:00:18 EDT
|> Subject: Re: solvent for duct-tape adhesive
|> you are removing the goo, use pure grain alcohol :-). If the alcohol does
|> not work try carbon tetrachloride. If neither of these work you may need to
                ^^^^^^^^^^^^^^^^^^^^

DO NOT HEAT THE CCL4 -- IT MAKES PHOSGENE GAS of WW-I poison gas fame

(remember when they used carbon tet in fire extinguishers?)


(yes, I know I was yelling)

-- 

	...Wex

Newsgroup: sci.electronics
document_id: 54340
From: wb8foz@fmsystm.ncoast.org (David Lesher)
Subject: HP 200CD manual

The 200CD is one of three oscillators that HP made many years ago. 
(The others were the Low Frequency Oscillator and the Wide Range 
Oscillator.) These are the ones with the 7" diameter chrome dial,
a Wein Bridge circuit that used pilot lights as the feedback loop,
and firebottles that produced many volts of output.

I've just acquired a pair of these venerable old beasts. 
The non-working one, SN 605, (owned by Crosley Radio at one point!)
needs help. I know I can likely buy a microfiche copy of the book 
from HP, but that costs.... and considering I paid a dollar for
the pair in the rain at the Dayton Hamvention;-}

Does anyone have such a book they could copy parts of for me?
Thank you....

Newsgroup: sci.electronics
document_id: 54341
From: zlau@arrl.org (Zack Lau)
Subject: Re: Why circuit boards are green?

In sci.electronics, swanee@megadata.mega.oz.au (Geoff Swan) writes:
>
>Rubbish. The reason for the colour of the boards depends on the solder

The May 1993 cover of QST has a picture of three different boards without
any solder mask (you can tell from the copper colored traces). The box
labeled 2304 transverter has the brown teflon/glass board, while the one
in the center has the grayish board exposed.  On the left is some 
fiberglass board that looks green to me.  I see no reason
for putting solder mask on circuit board used for box covers :-).

I wonder if any manufacturer actually puts a solder mask on their
low noise microwave preamps?  Often, microwave circuits have odd
bits of wire/foil/metal attached to wherever/whatever is necessary
to make the unit work properly (this is a commercial product?).  A
solder mask would certainly make doing this tougher, never mind 
the finding something that minimally degrades the circuits.  (Q dope
for coils *does* not improve the Q--it just holds things together with
minimal loss).

Zack Lau  KH6CP/1

Internet: zlau@arrl.org           "Working" on 24 GHz SSB/CW gear     
			          Operating Interests: 10 GHz CW/SSB/FM
US Mail: c/o ARRL Lab				       80/40/20 CW
	225 Main Street		  Station capability: QRP, 1.8 MHz to 10 GHz
	Newington CT  06111	               modes: CW/SSB/FM/packet
						      amtor/baudot
Phone (if you really have to): 203-666-1541

Zack Lau  KH6CP/1

Internet: zlau@arrl.org           "Working" on 24 GHz SSB/CW gear     
			          Operating Interests: 10 GHz CW/SSB/FM
US Mail: c/o ARRL Lab				       80/40/20 CW
	225 Main Street		  Station capability: QRP, 1.8 MHz to 10 GHz
	Newington CT  06111	               modes: CW/SSB/FM/packet
						      amtor/baudot
Phone (if you really have to): 203-666-1541

>mask that is used. Older boards (bakelite and phenolic) rarely used
>a solder mask (these boards are not suited well to automatic stuffing
>and soldering techniques) and hence are the colour of the compound
>used to make them. These days boards are made of fibreglass for most
>general purpose uses and have a solder mask applied to them to prevent
>close traces shorting to one another during soldering (and also to prevent
>the decomposition of traces under harsh environments). The light and dark
>green boards ofter seen have a "dry film" mask applied to them (usually
>applied as a complete film photographically produced). The blue (and red
>or orange) boards are a two-part epoxy or a liquid-imageable resist
>formulation and are applied in a different manner. There's a lot of info
>about the pro's and con's of each, but that's another story...
>
>    Sla/n go fo/ill,
>                    Risky B.
>--------------------------------------------------------------------------
>Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
>Megadata Pty Ltd                     /      \ 
>2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
>NSW 2113, Australia.                       v          (Fax) +61 2 887 4847
>
>
>
>

Newsgroup: sci.electronics
document_id: 54342
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: PC parallel I (!= I/O)

From article <1993Apr26.110250.5243@nmt.edu>, by erickson@azure.nmt.edu (Alan Erickson):
> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?
> 
> ------------------------------------------------------------------
> Alan Erickson   erickson@baltic.nmt.edu		
> 
> to all SunRayce '93 competitors: I hope you're getting
> about as much sleep as I am.....
> ------------------------------------------------------------------

I'M WATCHING ONE BEING BUILT RIGHT HERE AT UVM AND THE TEAM IS 
SHAGGIN' IT THESE DAYS.
                                 ME170PJD@UVM.EDU

Newsgroup: sci.electronics
document_id: 54343
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: PC parallel I (!= I/O)

From article <qekN3B4w165w@sys6626.bison.mb.ca>, by baden@sys6626.bison.mb.ca (baden de bari):
> erickson@azure.nmt.edu (Alan Erickson) writes:
> 
>> 	I'm trying to bring in 8+ bits to a PC, and would like
>> 	to use interrupt-driven routines. Without buying an IO
>> 	board or making a new port, _where_ can I bring in these
>> 	bits? LPT seems to have only a few inputs, but I've heard
>> 	rumours that some LPTs have bidirectional lines. Anybody
>> 	know fer sure? If any bi-d LPTs, which boards have them
>> 	(I'll be running a new 386DX-33)?
> 
>  
>         Yes, it is possible.  I'm making a 7 stepper controller board, 
> with 7 digital inputs, and (up to) 18 digital outputs from the // port.
>    One main thing that will tell you whether the // port is 
> bi-directional or not is the bus tranceiver on it.  Look for a chip 
> numbered 74LS245.  If you don't have this, then it's probably a 74LS244, 
> which will do you NO good for reading in.
>   
>           Now, if you do have the '245 then do the following:
>   First, find the address of the port, (decimal) either 888, or 632.
>   In pascal, you would "Write(Port[xxx]);" where xxx is the address in 
> either hex or decimal.  The status lines, pins 14, 16, 17, as well as the 
> strobe, pin 1, are bi-directional lines, and are read by base address +2, 
> so for 888, to read from status, then read from 890.  You can also output 
> to these lines in the same fashion as to the data lines.  In pascal, 
> do "Port[xxx]:=value
> ".
>  
>                 Hope this helps.
>         Let me know if you need more help.
>  
>  
>   _________________________________________________
>   Inspiration  |   ___                             |
>   comes to     |  \   o  baden@sys6626.bison.mb.ca |
>   those who    | (  ^  ) baden@inqmind.bison.mb.ca |
>   seek the     |   /-\      =] Baden de Bari [=    |
>   unknown.     |                                   |
>   ------------------------------------------------- 
>  

AS IT HAPPENS, YOU'VE HELPED ME QUITE A BIT. I'M CONSIDERING BUILDING
A VERY SIMILAR DEVICE JUST FOR SOMETHING TO DO THIS SUMMER.
THE IDEA IS TO CODE THE 8 OUTPUT BITS INTO MULTIPLE 2-BIT 
CURRENT-AMPLIFIED OUTPUT CHANNELS.  SOFTWARE WILL HANDLE THE WAY THE 
AMPLIFIED OUTPUTS ARE MANIPULATED SO THAT THIS MAGIC BOX CAN HANDLE
MORE APPLICATIONS THAN JUST STEPPER MOTORS.  ALSO LOOKING FOR A ROBOT ARM
(CHEAP) TO ATTACH THIS BOX TO SO I CAN WOW AND IMPRESS MY FRIENDS.
    ANY HINTS?       PETER J DEMKO ME170PJD@UVM.EDU 

Newsgroup: sci.electronics
document_id: 54344
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: ^^ Phosphorescent pads ...

baden@sys6626.bison.mb.ca (baden de bari) writes:

> 
>         A while ago I saw some translucent pads, about 6"x8" or so that 
>could be plugged into (something) and they would glow.  One was red, 
>another green, another blue.  Interresting.  I was wondering if anyone 
>would have a feed on anything of this nature, and of the price.
>   oh, the pads were rubber-like and were floppy like, about 1cm thick or 
>so.

The curiosities that you speak of are EL (Electro-Luminescent) pads.  They
are mostly used as backlights for LCD's, and as you pointed out, comes
in several different colors.  Many of them emit white-ish colors ("true"
white, and blue-whiteis-blue are the ones that I've personally encountered
the most often.)

They vary in their input requirements, however, they tend to operate at 
about 100 Vrms, and at much higher than 60 Hz.  (400 Hz to 1 kHz, if I 
recall correctly.)   You can get them to work at 120 Vrms, 60 Hz (i.e.,
line) but they don't glow as brightly, and they will degrade much faster.
(Oh yes, almost forgot, EL's have this tendency to wear out over time...)

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 | Dear IBM: Hire bunch of technically incompetent people
+1 818 449 5457    | (like my brother) to test OS/2 installation procedures.

Newsgroup: sci.electronics
document_id: 54345
From: mpaul@unl.edu (marxhausen paul)
Subject: Pressure Zone Microphones

I remember, back before commercial mikes with the "PZM" label (for
Pressure Zone Microphone) started showing up, I read an article,
in some engineering journal, that described the principles involved.
All the physics aside, from a practicle standpoint the author's said
they built a prototype with nothing more than a small Sony lavelier
mike laid up against a large aluminum disk.  In demonstrating it at
a presentation to audio engineers, this was impressive enough that
the people present were bugging them about where they could buy them.

Anyway...I want to build some to use as "choir mikes" (wide coverage).
I've had good luck using some small electret mike elements I got
from Digi-Key - most of these are limited-bandwidth, peakey units
but for a buck or two more I got the ones spec'd to go out to 20kHz
with a bit flatter response.  

The distance of the mike opening from the flat plate is kind of
critical.  I'm debating whether to mount it on it's side, which
puts the opening a shade under 2mm from the plate, or mounting
it with the opening actually pointing down into the plate at a
small clearance.  I haven't dissected a unit like you can buy at
Radio Shack to see how they do it.  Thoughts?


--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
document_id: 54346
From: jeffj@cbnewsm.cb.att.com (jeffrey.n.jones)
Subject: SPICE for XT with no co-processer?

I want to run SPICE on my XT so I can learn more about amplifiers
and oscilators. Is there a version of this that will run on my XT
with no math co-processer, if so where can I get it? Thanks for any
and all help!

Jeff
-- 
 Jeff Jones  AB6MB         |  OPPOSE THE NORTH AMERICAN FREE TRADE AGREEMENT!
 jeffj@seeker.mystic.com   |  Canada/USA Free Trade cost Canada 400,000 jobs. 
 Infolinc BBS 415-778-5929 |  Want to guess how many we'll lose to Mexico?

Newsgroup: sci.electronics
document_id: 54347
From: tgk@cs.toronto.edu (Todd Kelley)
Subject: Re: PC parallel I (!= I/O)

erickson@azure.nmt.edu (Alan Erickson) writes:

> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?

I know for sure that the Everex Magic I/O EV-170A can be jumpered
for a printer mode, or for a general purpose bidirectional I/O mode.

Also, I know for sure that the IBM Technical Reference says the following
about the Monochrome Display & Printer Adapter and the IBM Parallel Printer
Adapter:

    It is essential that the external device not try to pull these
    lines [referring to the data lines] to ground.

And later:

    If an external device should be driving data on these pins (in
    violation of usage ground rules) at the time of an input, this
    data will be `or'ed with the latch contents.

I will accept no responsibility if you incur damages of any kind
as a result of my saying, ``I DO NOT know for sure, but I think
you should be able to use a traditional parallel port as an input
port by writing 0x to the data lines, and then reading from the
data lines, while an external device drives them.''  The input
data will not be latched, so noise could make this infeasible.

Todd



Newsgroup: sci.electronics
document_id: 54348
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Why circuit boards are green?

In article <1993Apr27.051830.14545@mega.com.au>, swanee@megadata.mega.oz.au (Geoff Swan) writes:
> In article <1993Apr23.102039.1720@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
>> 
>> The color of the board shows the composition of it, hence the use of it.
>> 
>> Original and older boards were bakelite composition, and were brown.
>> Phenolic (spelling) was a tan
>> Most "non filled" fiberglass boards used in computers are green.
>> Filled fiberglass is blue.
>> Teflon is white.
>> 
> 
> Rubbish. The reason for the colour of the boards depends on the solder
> mask that is used. Older boards (bakelite and phenolic) rarely used
> a solder mask (these boards are not suited well to automatic stuffing
> and soldering techniques) and hence are the colour of the compound
> used to make them. These days boards are made of fibreglass for most
> general purpose uses and have a solder mask applied to them to prevent
> close traces shorting to one another during soldering (and also to prevent
> the decomposition of traces under harsh environments). The light and dark
> green boards ofter seen have a "dry film" mask applied to them (usually
> applied as a complete film photographically produced). The blue (and red
> or orange) boards are a two-part epoxy or a liquid-imageable resist
> formulation and are applied in a different manner. There's a lot of info
> about the pro's and con's of each, but that's another story...
> 
>     Sla/n go fo/ill,
>                     Risky B.
> --------------------------------------------------------------------------
> Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
> Megadata Pty Ltd                     /      \ 
> 2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
> NSW 2113, Australia.                       v          (Fax) +61 2 887 4847
> 
> 


Sorry Geoff,

Agree solder mask is green, but in the old days we didn't have wave soldering
machines (which are another topic again).  I had a crew of a dozen ladies which
could stuff and hand solder a board like lightning!

Board under the mask was the original query.

BTW cheap inport electronic devices (mainly from 3rd world countries) are done
with brown pheonolic boards.  Is seems the electronics industry has discovered
the cheap labor pools.  Workers are paid by the board to assemble circuits at
home.  They are very obviously hand soldered.  Quite a few tape recorders are
being brought into Canada from Red China.  In China there is no warranty for
the equipment other than if you plug it in and it works it's yours.  One of my
co-workers spent a year there and he said the failure rate out of the box was
almost 50%.

Also, the original method for making printed with conductive ink on a regular
printing press.  An old lithographer friend had a press for this.  After the
etching method was developed he used the press to print wood grain on doors.
> 
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
document_id: 54349
From: ferry@dutentb.et.tudelft.nl (Ferry Toth)
Subject: **** And now serious: E-Magazine *****


For some time I've been thinking about the possiblity of starting a group
where scientific articles can be published (or perhaps just summaries).
Possible advantages would be:
* Free disribution
* Fast acceptance
* Online discussion between authers and readers

This would be possible with one group with a moderator for publishing the
articles and one perhaps without for discussion.

The best thing would be if all the articles would be in a standard format which
would make it possible to print or view the documents camera ready. Perhaps
Postscript or Rich Text Format?

But how do you start a new group? Anyone interrested?

Greeting from Ferrie
Electronics Research Laboratory
Delft University of Technology
Delft
Holland

Newsgroup: sci.electronics
document_id: 54350
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: cleaning electronic equipment?

In article <adrian.735624685@tasman> adrian@tasman.cc.utas.edu.au (Adrian Lewis) writes:
>	Just a quick question.  What standard lab solvents can be used to
>clean electronic equipment and components safely (ie not corrode, dissolve,
>short-out, etc the equipment)?
>	water?	:-)
>	methanol?
>	CCl4?

You don't say what kind of "electronic equipment" you mean.  It's hard
to give a generic answer.  There is essentially no solvent that won't
do things like washing lubricant out of switches.

When we've needed to do an emergency cleaning job on things, we've just
used distilled water.  The key thing to remember is to make sure the gear
is *completely* dry before powering it up again.  We let it dry for
several days to be damn sure.

I doubt that methanol has significant advantages over water.  I would
be very wary of CCl4, not least because it is dangerous to *you* even
if it's not going to harm the equipment -- not only is it poisonous,
but I believe it's now known to be carcinogenic.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
document_id: 54351
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: Acceleration sensor?

In article <1993Apr27.145201.15495@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.
>Thanx, Mike
>Michael DeAddio (MTS)         | Work hard, play hard, 
>Bell Communication Research   | the only problem is that 
>deaddio@thumper.bellcore.com  | playing hard makes 
>201-829-5024                  | working harder.
>MRE 2Q-260                    | 

SETRA SYSTEMS, 4 Nagog Park, Acton, MA 01720, Ph: (617) 263 - 1400
Schaevitz Engineering,  US Rt. 130 & Union Ave., Pennsauken, NJ 08110
     Ph: (710) 892 - 0714

Accelerometers are not cheap, mainly because the outputs are fairly linear 
with respect to acceleration.  You don't say what the range of acceleration 
you want to measure is, and there are other ways in which to measure it 
other than using an accelerometer.  Additional information would be helpful 
to anyone who may respond.

Call, if you wish.

Newsgroup: sci.electronics
document_id: 54352
From: nagle@netcom.com (John Nagle)
Subject: Re: Why circuit boards are green?

ulan@ee.ualberta.ca (Dale Ulan) writes:
>kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:
>>Not that the question is anything important, but I am still curious:
>>Why is that almost all printed circuit boards are green? I have seen
>>a few blue ones, but no red, yellow, company logo etc. Is there a
>>technical reason or could it be that the marketing "geniuses" have
>>not tought about it (yet)?

       It's possible to make boards in other colors, and I have an ad
for laser light-show equipment which offers the circuit boards in your
choice of Day-Glo (tm) colors.

       The usual light green color is just the natural color of Fiberglas.
The dark green or blue is the solder mask layer, and I suspect that color
is a dye.  

						John Nagle

Newsgroup: sci.electronics
document_id: 54353
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Pressure Zone Microphones

In article <1rjobdINNk1s@crcnis1.unl.edu> mpaul@unl.edu (marxhausen paul) writes:
>I remember, back before commercial mikes with the "PZM" label (for
>Pressure Zone Microphone) started showing up, I read an article,
>in some engineering journal, that described the principles involved.
>All the physics aside, from a practicle standpoint the author's said
>they built a prototype with nothing more than a small Sony lavelier
>mike laid up against a large aluminum disk.  In demonstrating it at
>a presentation to audio engineers, this was impressive enough that
>the people present were bugging them about where they could buy them.

Yup, it's not all that difficult to do.

>Anyway...I want to build some to use as "choir mikes" (wide coverage).
>I've had good luck using some small electret mike elements I got
>from Digi-Key - most of these are limited-bandwidth, peakey units
>but for a buck or two more I got the ones spec'd to go out to 20kHz
>with a bit flatter response.  

The Panasonic cartridges aren't bad, but they aren't spectacular.

>The distance of the mike opening from the flat plate is kind of
>critical.  I'm debating whether to mount it on it's side, which
>puts the opening a shade under 2mm from the plate, or mounting
>it with the opening actually pointing down into the plate at a
>small clearance.  I haven't dissected a unit like you can buy at
>Radio Shack to see how they do it.  Thoughts?

Don't mount it on the side.  Call up Crown, the company that has the
patent on the PZM, and ask them for information on construction and
use of the things.  You may have to determine the correct spacing
emperically with a noise source and a spectrum analyzer because the
design of the Panasonic cartridges uses a tuned cavity in front of
the electret element to increase the high frequency response, and you
are going to be altering the resistance through the cavity entrance.

Crown has a nice book on the subject, though it's unfortunately rather
short on mathematics.  There's a JAES article from many years back, too.

Still, for your application, you'll be a lot better off buying the cheap
Radio Shack models and using Phil Rastoczny's modifications to get a
clean balanced output.  Phil's mods seem to get reposted here on a regular
basis.
--scott

Newsgroup: sci.electronics
document_id: 54473
From: nds@dcs.ed.ac.uk (Neil D Stevenson)
Subject: Re: Picking up cable tv with an aerial.

In article <1993Apr27.202305.4363@mav.com>, toddi@mav.com (Todd Inch) writes:
> In article <1993Apr16.003132.1@wcsub.ctstateu.edu>
> ritterbus001@wcsub.ctstateu.edu writes:
> 
> Regarding pointing an antenna at a "leaky" CATV cable:
> 
> >Wow, what a concept!  Does anybody want to speculate on how this
> >"non-connection" would fit into the theft of cable services laws?
> >It seems to me that unless this case is specifically written into
> >the legislation that the cable company would not have a leg to
> >stand upon in court.
> 
> Well, the CATV company, in the US, is accountable to the FCC for how
> much transmission their cables make.  In fact, I've heard first hand
> about how the CATV company asked to inspect the wiring in a
> home/business to find the source of RF leaks.  I've heard many of their
> vans have RF detectors and they keep one eye on them as they drive down
> the street.
> 
> If the cable is leaky enough to have usable signal, I would GUESS that
> they're probably in violation of FCC transmission laws.
> 
> In England they do (did?) require permits to OPERATE A TV!!!
> Supposedly, the "TV police" drove around with RF detectors looking for
> the IF or whatever produced by a receiver that wasn't registered.  I'm
> guessing the purpose was just something else they could get away with
> taxing.  I don't know if the "TV police were/are just urban legend or
> an actuality.

The TV Police are still with us I'm afraid. A 1000 pound fine goes out to
the unlicensed users(if caught).

Newsgroup: sci.electronics
document_id: 54474
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: Picking up cable tv with an aerial.

In article <1993Apr27.202305.4363@mav.com> toddi@mav.com (Todd Inch) writes:
>
>In England they do (did?) require permits to OPERATE A TV!!!
>Supposedly, the "TV police" drove around with RF detectors looking for
>the IF or whatever produced by a receiver that wasn't registered.  I'm
>guessing the purpose was just something else they could get away with
>taxing.  I don't know if the "TV police were/are just urban legend or
>an actuality.

They are real, and we still pay licence fees to receive TV.
The detector vans pick up the IF, true. This tells them what channel you
are watching. The can also pick up the line time base freq, and frame rate
(Try it with a LW/MW radio near telly, it picks up a sharp hum)

From this they can even watch (poor quality though) what *you* have on the
screen, by picking up re radiating junk.

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
document_id: 54477
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: Microcontroller Questions for newcomer

Does anyone have recommendations on whether a smart data I/O (print spooler,
digital sampling, etc.) would be better implemented with a DMA chip or a
dedicated microcontroller?  Essentially what I am trying to decide is the best
way to handle moving data from a port with automatic handshaking from or to a
memory area that will be accessible by a main system processor when not in use
by the smart data I/O.
 
Which DMA or microcontroller chip would be best to use?  Fast, cheap, and easy
to obtain would be nice, but I won't limit my choices to only those that fit
those characteristics.  Even an 8086/8088 (under $5) would do what I want,
but I am sure there is a better alternative -- like a microcontroller with
onchip (E)EPROM.
 
So I essentially want to hear about all DMA and microcontrollers that are simple
to interface and will move data from one place to another while monitoring a
few I/O lines.
 
Jeff White          jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
document_id: 54478
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: **** And now serious: E-Magazine *****

Ferry Toth writes:

>For some time I've been thinking about the possiblity of starting a group
>where scientific articles can be published (or perhaps just summaries).
>Possible advantages would be:
>* Free disribution
>* Fast acceptance
>* Online discussion between authers and readers

>This would be possible with one group with a moderator for publishing the
>articles and one perhaps without for discussion.

>The best thing would be if all the articles would be in a standard format which
>would make it possible to print or view the documents camera ready. Perhaps
>Postscript or Rich Text Format?

>But how do you start a new group? Anyone interrested?

>Greeting from Ferrie
>Electronics Research Laboratory
>Delft University of Technology
>Delft
>Holland

Yep! Sounds good to me. suggestion: sci.electronics.art ?

Best regards,

Wouter


Newsgroup: sci.electronics
document_id: 54479
From: srl@terminus.ericsson.se (Steve Langstaff)
Subject: Re: How universal are phones these days?

In article 1rjq8hINN8je@dns1.NMSU.Edu, rpeter@nmsu.edu (Peter Herman x5495) writes:
:>In <LHE.93Apr26131014@yang.sics.se> lhe@sics.se (Lars-Henrik Eriksson) writes:
:>
:> I would not be suprised if the equipment is compatible, in fact New York
:>Telephone (NYNEX) spend a lot of money on Swedish switching equipment
:>recently.
:>
:>>Lars-Henrik Eriksson                            Internet: lhe@sics.se
:>
:> You can guess what brand of equipment I refer to :-)
:>
:	Lars-Henrik will be pleased to know that his name is
:plastered all over phones at New Mexico State University as well.
:They got the contract when NMSU went to a digital phone system.
[snip]

Not quite correct! The company name is Ericsson. (With a 'c').


---

Steve L.


Newsgroup: sci.electronics
document_id: 54480
From: srl@terminus.ericsson.se (Steve Langstaff)
Subject: Re: solvent for duct-tape adhesive?

In article 6746@mprgate.mpr.ca, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:

:Lighter fluid is butane.  It's absolutely non-toxic but is an extreme fire
         ^^^^^    ^^^^^^        ^^^^^^^^^^^^^^^^^^^^
:hazard.  You definately don't want to go splashing this stuff around.
:(Use a little on an old rag.)

Butane : "A colourless flammable gaseous alkane..."

Non-toxic? It has some effects when you inhale, allegedly, which can't all be down
to asphyxia (IMHO).




---

Steve L.


Newsgroup: sci.electronics
document_id: 54481
From: szh@zcon.com (Syed Zaeem Hosain)
Subject: Re: Acceleration sensor?


In article 15495@walter.bellcore.com,  deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.
>
>Thanx,
>
>Mike

I am not sure about this, but I believe that Analog Devices in Norwood,
MA makes a relatively inexpensive acceleration sensor (primarily for
use in auto air-bag systems). I do not know specs or anything else, but
you might give them a call to find out more info.

								Z


-- 
-------------------------------------------------------------------------
| Syed Zaeem Hosain          P. O. Box 610097            (408) 441-7021 |
| Z Consulting Group        San Jose, CA 95161             szh@zcon.com |
-------------------------------------------------------------------------

Newsgroup: sci.electronics
document_id: 54482
From: ftqz@aurora.alaska.edu
Subject: Re: CAD Program for Electronics?

In article <1r73vqINNftu@zephyr.grace.cri.nz>, srgxnbs@grace.cri.nz writes:
>>>What I want the CAD program to do is to draw diagrams by
>>>dragging elements onto the screen, and in this the elements
>>>needed are as diverse as vacuum tubes to ICs (case with pins).
> ..
> try DraftChoice, its not windows but its shareware and object
> oriented. Use it with PrintGL for high quality output.
> 
> Bruce
> 
> 
Look for Spice or PSpice

Newsgroup: sci.electronics
document_id: 54483
From: ftqz@aurora.alaska.edu
Subject: Re: Looking for a good book on Pspice 5.2

In article <C65EGz.BG1@acsu.buffalo.edu>, v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
> 	I just got a copy of spice 5.2. I would like to know if there are
> any published books on the market yet and where I could get one. I would
> appreciate any help. Thank You
> 
> 		Neil Gandler
> 
ISBN 0-13-747270-6

Newsgroup: sci.electronics
document_id: 54484
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Long distance IR detection

jvannes@vms.macc.wisc.edu writes:....
> >I designed and built hardware in 1988 that would output a logic level (from
> >a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
> >Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
> >variations in sunlight (and 60Hz from lights). Used no lenses.
> >Allen Sullivan
> I would be interested in knowing more about the sensing hardware.  What did
> you use for the detector?  Could you detect the angle of location, or did
> the system simply respond to the presence of the transmitter in the sensors
> field of view?
 
Phototransistor-> X100 -> X100 -> NE567
with 330Kohm              Limiter 
feedback to base                  
to control operating point (I expect this really hurts Noise Figure! Any
comments from Phototransistor experts?)

We intended to use this atop a stepper motor, to provide headings to the
beacons. The plan was to have 3 or 4 beacons, of different frequencies, in 
each room, and tell the 567 what frequency to phase-lock to. We did not do so.
One challenge was that the available stepper had 8 degree steps!
Knowing the headings to each beacon, we would have used the surveyor 
technique of RESECTION to determine robot location. (No, I ain't going to
explain resection over the net.)

Given hindsight, I would digitize the amplified output of the self-nulling
phototransistor circuit, and correlate in-phase & quadrature square-waves at
the several expected frequencies, to extract AMPLITUDE of each beacon.
By doing this at the numerous steps, even with  8 degree steps, with knowledge
of the angular response of the phototransistor, you SHOULD be able to
rather more accurately determine the heading to each beacon.
Allen Sullivan



Newsgroup: sci.electronics
document_id: 54485
From: Thomas.Tornblom@Nexus.Comm.SE (Thomas Tornblom)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:

   In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

   > I'm wondering if I can tote my American touch tone phone around with me
   > to Sweden and Germany.  It's DC powered, and I can buy a special adapter
   > for that in Europe.  The question is if the general electronics work
   > the same.  I can buy a different wall plug and refit it (I'm sure I'd
   > have to), but would that do the trick?

   Two things to watch for:
   In Germany (and I think the same holds for Sweden) only some
   of the connections can handle tone dialing, so make sure the
   phone can be set to pulse dialing.
   In Sweden, the '0' is the first digit and all other digits
   are pushed "down" by one position; this makes dialing (and
   in the process converting numbers) an interesting task.
   Otherwise, it is technically no problem to connect a foreign
   phone to either the German or Swedish phone system.
   OTOH neither you nor I would ever try that, as it is of course
   illegal.

As the phone uses DTMF dialing, which by some magic all telecom
operators seems to have agreed on, this is a complete non-issue.

I don't think there are any switches in Sweden that can't handle DTMF
dialing. Most switches are now digital and thoses that aren't have
been retrofitted with "magic fingers" that converts from DTMF to pulse
dialing.

Thomas
--
Real life:      Thomas Trnblom           Email:  Thomas.Tornblom@Nexus.Comm.SE
Snail mail:     Communicator Nexus AB     Phone:  +46 18 171814
                Box 857                   Fax:    +46 18 696516
                S - 751 08 Uppsala, Sweden

Newsgroup: sci.electronics
document_id: 54486
From: wd@cs.tu-berlin.de (Wolfgang Diestelkamp)
Subject: Re: How universal are phones these days?

In article <26APR199315293014@utkvx.utk.edu> iturriag@utkvx.utk.edu (Mr. Y) writes:

> I am not quite so sure about the illegality of using a regular American phone
> on your home system. I vaguely remember a few years ago, when "Deutsche
> Bundespost" split into Postdienst, Postbank, and Telekom there was some
> discussion about a new regulation. I know that cordless or cellular phones
> still have to be approved by the Telekom, but does that hold true for regular
> phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use

Yes, it does.
All the equipment has to have that Telekom approval number to be
legal.
What has changed is that you can buy the equipment somewhere else.
I'm pretty sure the same holds true in Sweden (at least when I read
some information on it about tweo years ago).
And BTW I do know that most of the lines in Sweden can handle tone-dialing,
just don't be sure that all can.

-- 
Wolfgang Diestelkamp
wd@cs.tu-berlin.de
wolfgang@first.gmd.de


Newsgroup: sci.electronics
document_id: 54487
From: kurtg@drycas.club.cc.cmu.edu
Subject: Re: Ultrasonic pest repellers: Stories, advice, bunk, etc.?

In article <babb-280493102418@larc.sdsu.edu>, babb@sciences.sdsu.edu (J. Babb) writes:
> RE: Ultrasonic pest repelling devices. The ones I've seen use piezoelectric
> transducers driven by a 35-85 KHz swept oscillator. Is there evidence that
> insects are actually repelled by these devices? Can anybody cite gov't
> pubs, or independent lab studies?
> 
> I saw another device that supposedly repels pests by "altering the
> electro-magnetic field of your house wiring". I suppose they capacitively
> couple a hi freq signal to the AC wiring. And this is supposed to repel
> pests???? How? By magnestriction of the wiring? I DONT THINK SO. 
> 

I've been wondering about this myself.  The house wiring thing is really
hokey.  There is no doubt that high pressure ultrasound is annoying, but to
whom?  Given that these devices have been advertised to be effective against
everything from insects to rodents to nasty dogs, what is to say that my
insect repeller won't just annnoy my dog and give me headaches?  Could there
be that much selectivity in frequencies?  Have there been ANY studies
on the effects of various pressure levels, bands, and sweep patterns on
various life forms?

And how effective could they be?  I certainly would not want to tell anyone
that they are safe from nasty dogs because they were carrying a piezoelectric
buzzer...

> 
> Jeff Babb
> babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
> Programmer, SDSU - LARC
-- 
Kurt A. Geisel                        SNAIL : 7 Quaker Rd.
White Pine Software, Inc.                     Nashua, NH 03063
ARPA2 : kurtg@drycas.club.cc.cmu.edu  BIX   : kgeisel
GENIE : K.GEISEL                      AIR   : N3JTW
"I will not be pushed, filed, indexed, stamped, briefed, debriefed, or
numbered!" - The Prisoner

Newsgroup: sci.electronics
document_id: 54488
From: bnguyen@airmics.gatech.edu (Binh Nguyen)
Subject: Re: solvent for duct-tape adhesive?


Another alternative is to cover the adhesive with another piece of
duct tape then remove the tape. 

If it still doesn't work, try WD-40.
BQN


In article <C67stK.FoK@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu
(Michael Covington) writes:
|> In article <stephens.736002130@ngis> stephens@geod.emr.ca (Dave
Stephenson) writes:
|> >mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
|> >>>>
|> >>>I don't know for sure that this will work, but you might try MEK
(methyl
|> >>>ethyl keytone?).  It worked getting the stickum left over from
shelf paper,
|> [etc.]
|> >If you use MEK for your sake wear safty glasses or better still
|> >industrial goggles. The small est drop in the eye will casue  
[etc.]
|> 
|> Please watch those attributions.  It was NOT ME that advocated using
MEK.
|> 
|> -- 
|> :-  Michael A. Covington, Associate Research Scientist        :   
*****
|> :-  Artificial Intelligence Programs      mcovingt@ai.uga.edu : 
*********
|> :-  The University of Georgia              phone 706 542-0358 :   * 
*  *
|> :-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  **
*** **  <><

Newsgroup: sci.electronics
document_id: 54489
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: Passive Mixer

shaffer-wendy@yale.edu (Wendy Shaffer) writes:

>I'm trying to build a mixer for a friend of mine to run several things into
>a single boom box.  I have a circuit that uses an op-amp powered by either a
>couple of 9V batteries or using some kind of power supply.  But in a catalog
>I was looking at recently, a "passive mixer" for guitar was advertised taht
>doesn't appear to use any power at all.  Does anyone know what the circuit for
>this would be, because then I could just adapt it for RCA jacks, and save my
>friend and I alot of messing with batteries and plugs.  Thanks.

Well, the fastest, crudest mixer (aside from just physically connecting
all your inputs together directly) is to run each signal through a 
resistor to a common output.  The resistors give some isolation so the
signal sources aren't driving directly into each other. 

Taking a wild, seat-of-the-pants guess, I'd say that if you are mixing
high-impedance sources like some dynamic mikes, electric guitar pickups,
etc., your resistors ought to be maybe 5K - 10K or so.  If you are mixing
line-level stuff or the outputs of a Walkman, or such, I'd go with 1K.

input 1 --/\/\/\/ -------------+--- output
                               |
input 2 --/\/\/\/\-------------+
                               |
input 3 --/\/\/\/\-------------+


--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
document_id: 54490
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead ACid Batteries Part 2!!!

In article <1993Apr27.211036.1@ulkyvx.louisville.edu> jhwhit01@ulkyvx.louisville.edu writes:
>In article <1993Apr26.221422.17208@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>
<lots of stuff deleted>

>The lead-acid secondary cell discharge reaction is EXOTHERMIC.  I am glad
>you do not dispute this point.  If you don't want the lead storage battery
>to discharge, it should be stored such that its charged state is the
>equilibrium state.  During winter, the ground, be it covered with
>concrete, dirt, or wood, maintains a cooler temperature on average than
>the surrounding air or the battery.  The heat capacity of air is less than
>that of concrete, dirt, or wood, so it heats faster.  Conversely, air cools
>faster, too.
>
>The normal storage procedure for a battery is to leave it in an unheated
>garage or basement.  The storage surface is often cooler than the
>surrounding air, with the battery temperature somewhere in-between.  E.g.,
>the basement air temperature may be 70 F, the floor temperature 65 F, and
>the battery temperature 66 F.
>
>The air temperature is HIGHER than the battery temperature.  The heat of
>reaction is not going to move up the gradient.  The floor temperature is
>LOWER than the battery temperature, and heat is going to move to it.  The
>floor is an incredible heat sink.
>

Might depend on where you live .. I know locally, for most of the winter
the ground, and concrete floor, within sheds and garages (unheated) is
signifacantly warmer than the average air temperature.  The air does get
warmer during the day, but during the night, the ground and concrete
is definitely warmer, especially when protected by the walls from the
albedo effect.  And the nights are longer by several hours than the
days.

<rest of quoted text deleted>
>
>Jeff White       jhwhit01@ulkyvx.louisville.edu

Richard Dell

Newsgroup: sci.electronics
document_id: 54491
From: reynhout@cs.uri.edu (Andrew Reynhout)
Subject: Re: Microcontroller Questions for newcomer

acooney@netcom.com (Alan Cooney) writes:
>...discussion of Motorola vs Intel uC's
>
>In other words, just add your favorite serial level converters (Mac folks
>can use the cheaper, farther, and faster RS422 drivers, PC users get to
>suffer with RS232...) and start using your project!  Think about it...

   How much software is out there for the Mac?  I've been interested
in using microcontrollers in imbedded applications for a long time,
but was always under the impression that I would need an IBM to run
the debug/compile/etc software.
   I would like to use a 6811 or 6816.  I'm proficient in 6800 assembly,
but have never NEEDED it except some toying with old 6802EVBs.

   Motorola doesn't seem to have any information on Mac software (at
least their local distributor doesn't) and the ELE department around
here has been of little help as well.
   I hope someone can tell me that I don't have to buy an IBM to 
work with the 6811 or 6816 Evaluation Boards...please send me mail!

   Andrew
-- 
   Andrew <reynhout@cs.uri.edu>    "If you remind me of my dog,
                                    we'll probably get along"  -jane siberry
   meow

Newsgroup: sci.electronics
document_id: 54492
From: tony@morgan.demon.co.uk (Tony Kidson)
Subject: Re: How universal are phones these days? 

In article <1993Apr27.010612.17126@chpc.utexas.edu> michael@chpc.utexas.edu writes:

>
>Does this imply the German tone dialing is compatible with the American
>one?  I know at least the British system is not -- it is supposedly close
>enough though that an American phone will work.  But my modem (American)
>has a special setting for British standards...
>

Bzzzzzt! Wrong answer.  The UK tone dialling is identical to the US system. 
The different settings on your modem are so that it uses CCITT V21 & V22 
tones for data transmission, rather than Bell 103 & Bell 121 tones, which are 
used only in the USA and canada AFAIK.  As most people now use at least 
V22bis, this is largely irrelevant.

Tony



+---------------+------------------------------+-------------------------+
|Tony Kidson    | ** PGP 2.2 Key by request ** |Voice +44 81 466 5127    |
|Morgan Towers, |  The Cat has had to move now |E-Mail(in order)         |
|Morgan Road,   |  as I've had to take the top |tony@morgan.demon.co.uk  |
|Bromley,       |  off of the machine.         |tny@cix.compulink.co.uk  |
|England BR1 3QE|Honda ST1100 -=<*>=- DoD# 0801|100024.301@compuserve.com|
+---------------+------------------------------+-------------------------+

Newsgroup: sci.electronics
document_id: 54493
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

I was a bit surprised that the manual for my Fluke-87 multimeter
suggests applying WD-40 to the test lead sockets, especially the
current range socket.  The intention is to prevent the
test-lead-is-in-the-wrong-scocket beeper from going off when there
is no test lead in that socket.

The manual is a bit vague, but I think I'd apply the WD-40 to a
swab, then wipe the socket instead of spaying the stuff directly
from the can.

Speaking of said meters:  I compared the 87 against the 8060A that
I've had on my bench for almost 11 years.  It has been five years
since the 8060A has been calibrated.  On the DC scale, they agree
within .01 mV.  AC scale is within about .1 mV.  The 87 would be
just about the perfect portable meter if it had the dB scale; I
didn't feel it was worth the extra $100 for a second 8060 since I
don't use dB all that much in my work.

-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 54494
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Using generated power on large sound systems?

In article <1rk733$ekv@slack.sim.es.com> pashdown@slack.sim.es.com (Pete Ashdown) writes:
>
>I've bothered the rental shops and audio shops about the problem, but most of
>them have precious little experience in dealing with generated power.  My
>suspicion is that I don't really need anything larger than 2KW and this could
>all be resolved with a transformer of some sort.

Nope.  Your problem is either being caused by excessive voltage drop in the
long cable from the generator, or just plain not having enough power.  I
would suspect that those amps are going to draw a lot of current on short
peaks.

You can try using larger (and shorter) cables to the generator, or try
strapping the amps for 240V service and running 240V mains cables out,
which will minimize the line drop.  If these don't work, though, you're
going to need a bigger generator.

I assume that you're using well-maintained generators, and have watched the
voltage output on the generator properly.  If you don't have 120V coming out
of the unloaded generator you'll never get 120V at the other end.

>Can anyone offer any advice?  I want to do a lot of outdoor events this
>summer, and it would be nice if this power problem could be resolved easily.
>I've been looking into buying a power-pack so I could tap into junction boxes
>directly, but have no idea where to start.  One that would resolve my
>generator problems as well would be of high value to me.

I recommend you talk with an electrician who has experience in this sort of
work, and not with the pro-audio people.  Also, I recommend that you don't
try to tap into junction boxes at all, but hire a licensed electrician if
you don't really know what you are doing.  I've had to clean up after two
people who nearly killed themselves playing in hot 200A boxes, and it wasn't
much fun.
--scott

Newsgroup: sci.electronics
document_id: 54495
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Accelerometer request re-specified

In article <1993Apr27.190648.26436@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>
>Basically, I am looking for something to operate in the
>ranges of accelerations found in an automobile environment.
>I would like the device to operate as a trigger for other
>systems when the car's deceleration reaches a threshold value
>(which is how I assume some seat belt lock mechanisms and air
>bag deployment systems work?).

Open up one of the airbag control boxes.  They have inexpensive piezoelectric
accelerometers in them.  I know that the GM cars use the Setra units.  The
cheapest way to get such an accelerometer is to cannibalize an existing
automotive unit.

Incidentally, these things aren't very linear, but for the application they
would do a fine job.
--scott

Newsgroup: sci.electronics
document_id: 54496
From: katop@astro.ocis.temple.edu (Chris Katopis)
Subject: Phantoms in my Sony STRVX550 Receiver


While I have gotten 8-9 years out of this digital receiver, it
has been acting VERRY strange of late.  I hope that  the following	
symptoms may help someone diagnose the error:

- i know that whatever lithium memory backup it had - has long died
thus if i unplug it - it won't remember the presets

- it has given up listening to the remote.  (i tried changing the remote's
batteries) when i try a remote function - the receiver registers that it
received it (a green remote light flashes) but the right function
doesn't happen - if any function at all.  (also strange- when i hit 
the "mute" button, for example, the display panel goes black - yikes-	
i've never seen that before ...)

- before all the strangeness started, the system turned itself OFF and ON
again - by itself

- sometimes it won't play a radio station, so i have to kinda twist it 
(yes kinda flex the motherboard, chasis) for it to get the radio
tuning back - the aux in function always works however....

it is inconvenient, but NOT inconvenient enough to pay an 
expensive repair fee.  while, i'm not a hardware guy, i wonder 
if something as simple as a surge supressor will be a quick fix.
the strange thing is that these symptoms come and go ...

someone told me this unit series has a bad Voltage Amp chip.

-anyway  ...arghh
-cjk
 

Newsgroup: sci.electronics
document_id: 54497
From: stephens@geod.emr.ca (Dave Stephenson)
Subject: Re: solvent for duct-tape adhesive?

mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>>>
>>I don't know for sure that this will work, but you might try MEK (methyl
>>ethyl keytone?).  It worked getting the stickum left over from shelf paper,
>>and is available at paint stores.  Use a carbon gas mask and lots of
>>ventilation--this stuff really stinks!


>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><
If you use MEK for your sake wear safty glasses or better still
industrial goggles. The small est drop in the eye will casue
blindness by a catalysis reaction that is non cureavble once it starts.
The results are similar to mustard gas contamination. Note MEK peroxide
is a hardner form fibreglass resins.
--
Dave Stephenson
Geological Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca

Newsgroup: sci.electronics
document_id: 54498
From: dwb@cbnewsb.cb.att.com (david.boyle)
Subject: Re: solvent for duct-tape adhesive?

> > mahy comments deleted........
> 
> RONG WRONG!!  Butane is used in a BUTANE lighter...Zippo's
> use petroleum naptha and perfume..
> BTW...if you wanna find some benzene...take a look at
> aerosol spray GUMOUT Carberetor Cleaner..that stuff will
> take of the adhesive..and the paint and melt plastic and
                                       ^^^^^^^^^^^^^^^
This doesn't melt plastic, at least it hasn't melted the plastic 
bottle that I bought it in yet.  Maybe I'd better go check that
bottle, its been sittin' awhile -:)

Newsgroup: sci.electronics
document_id: 54499
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: **** And now serious: E-Magazine *****

In article <1993Apr27.152314.28798@donau.et.tudelft.nl> ferry@dutentb.et.tudelft.nl (Ferry Toth) writes:
>Subject: **** And now serious: E-Magazine *****
>Summary: How about starting a group where scientific articles can be pre-publish
>Keywords: Scientific papers, Electronic magazine
>
>For some time I've been thinking about the possibility of starting a group
>where scientific articles can be published (or perhaps just summaries).
>Possible advantages would be:
>* Free distribution
>* Fast acceptance
>* Online discussion between authors and readers
>
>This would be possible with one group with a moderator for publishing the
>articles and one perhaps without for discussion.


I think its a great, but idealistic idea. A reseacher will first of all try 
to publish a worthy paper in a credible, professional magazine and not in a 
community like USENET which is infamous for lots (not all) of junk 
information. The papers that will be "published" here will, in general, be 
of low quality. Also, it is improbable that any credit will be given to a 
researcher who publish here - and sadly, that is nowadays a main reason for 
publishing.

USENET is great for informal discussions and free exchange of ideas - keep 
it like that. A new, specialist group is just not worth it.

- gerrit

Newsgroup: sci.electronics
document_id: 54500
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Why circuit boards are green?

Fiberglass boards are available in several colors.  Sitting right
here, I have unetched board stock that is white, blue, green and
yellow respectively.  I've also seen black boards.

Solder mask is available in a variety of colors too.  Depending on
the supplier, the color helps indentify the material.

Don't forget conformal coating.

I don't think I've seen phenolic impregnated paper boards in
anything other than the familar brown, but it would not be
difficult to add a dye to change the color.

-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
document_id: 54501
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: How to make the disks copy protected (continued)

In article <sehari.735962071@du139-201.cc.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>From: sehari@iastate.edu (Babak Sehari)
>Subject: How to make the disks copy protected (continued)
>Date: Wed, 28 Apr 1993 01:54:31 GMT
>---
>
>The discussion under the old topic went in the wrong direction.  Some people,
>instead of discussing the issue itself, they decided to discuss the
>non-technical part of the issue.  So, Here I go with my limited knowledge
>about this issue.  Hoping you guys cut the crap and talk about the real
>technical ways to do this.  The methods that I am aware that are effective
>are:
>
>1- Laser hole burning.  This would leave the disk damaged, so if you format
>   that particular sector of the disk you can not write to it.  It is very 
                                           ^^^^^^^^^^^^^^^^^^^
Laser holes are (or were) used to prevent someone from making exact copies 
of a disk. You do not want to write to the damaged disk, only read and use 
the programs.

>   hard for crackers to damage the disk exactly the same way.
>

I remember a program called Copywrite that could copy a disk with a laser 
hole in it. I think it simulates the laser hole. After copying the disk the 
program is, if necessary, used in conjunction with a program called Nokey or 
something. (The program tells you which program to use)

No solution.

- gerrit

Newsgroup: sci.electronics
document_id: 54502
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: info on flux gate coils/magnetometer?

In article <bbuck.735977235@Endor> bbuck@Endor.sim.es.com (Bryce Buck) writes:
>Subject: info on flux gate coils/magnetometer?
>Keywords: flux gate, magnetometer.
>I am interested in finding sources and design information on flux gate coils 
>or flux gate magnetometers (digital compass). Please respond via E-mail.

Sorry, my news reader doesn't want to reply.

1) Ling, S.C. "Fluxgate magetometer for Space Application", IEEE Journal 
Spacecraft, Vol. 1, No. 2, March-April 1964, pp 175-180.

Oldish, but usable. Background information

2) "Fluxgate magnetometry", Electronics world + Wireless world, September 
1991, pp. 726-732.

Great! Circuit diagrams etc for building an electronuc compass

- gerrit

Newsgroup: sci.electronics
document_id: 54503
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead ACid Batteries Part 2!!!

In article <C6728H.Luy@cbfsb.cb.att.com> rdell@cbnewsf.cb.att.com (richard.b.dell) writes:
>In article <1993Apr27.211036.1@ulkyvx.louisville.edu> jhwhit01@ulkyvx.louisville.edu writes:
>>In article <1993Apr26.221422.17208@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>>
><lots of stuff deleted>
>
>>The lead-acid secondary cell discharge reaction is EXOTHERMIC.  I am glad
>>you do not dispute this point.  If you don't want the lead storage battery
>>to discharge, it should be stored such that its charged state is the
>>equilibrium state.  During winter, the ground, be it covered with
>>concrete, dirt, or wood, maintains a cooler temperature on average than
>>the surrounding air or the battery.  The heat capacity of air is less than
>>that of concrete, dirt, or wood, so it heats faster.  Conversely, air cools
>>faster, too.
>>
>>The normal storage procedure for a battery is to leave it in an unheated
>>garage or basement.  The storage surface is often cooler than the
>>surrounding air, with the battery temperature somewhere in-between.  E.g.,
>>the basement air temperature may be 70 F, the floor temperature 65 F, and
>>the battery temperature 66 F.
>>
>>The air temperature is HIGHER than the battery temperature.  The heat of
>>reaction is not going to move up the gradient.  The floor temperature is
>>LOWER than the battery temperature, and heat is going to move to it.  The
>>floor is an incredible heat sink.
>>
>
>Might depend on where you live .. I know locally, for most of the winter
>the ground, and concrete floor, within sheds and garages (unheated) is
>signifacantly warmer than the average air temperature.  The air does get
>warmer during the day, but during the night, the ground and concrete
>is definitely warmer, especially when protected by the walls from the
>albedo effect.  And the nights are longer by several hours than the
>days.
>
><rest of quoted text deleted>
>>
>>Jeff White       jhwhit01@ulkyvx.louisville.edu
>
>Richard Dell

Sorry about following up my own article, but I wanted to continue
that what might be being missed here is that the important thing
might not be temperature differences per se, but the action of
heat sinking the battery.

Perhap someone could conduct an experiment, taking two identical
lead acid batteries, placing both on wooden shelves, but putting
one of them in a water bath designed to act as a heat sink.  This
would eliminate the 'concrete floor effect', and keep both batteries
at the same ambient temperature.

I think the argument over temperatures is not pertinent, but the
one over heat conductance and removing the exothermic heat may have
some validity.

Richard Dell


Newsgroup: sci.electronics
Document_id: 52434
From: et@teal.csn.org (Eric H. Taylor)
Subject: Re: HELP_WITH_TRACKING_DEVICE

In article <00969FBA.E640FF10@AESOP.RUTGERS.EDU> mcdonald@AESOP.RUTGERS.EDU writes:
>[...]
>There are a variety of water-proof housings I could use but the real meat
>of the problem is the electronics...hence this posting.  What kind of
>transmission would be reliable underwater, in murky or even night-time
>conditions?  I'm not sure if sound is feasible given the distortion under-
>water...obviously direction would have to be accurate but range could be
>relatively short (I imagine 2 or 3  hundred yards would be more than enough)
>
>Jim McDonald

Refer to patents by JAMES HARRIS ROGERS:
958,829; 1,220,005; 1,322,622; 1,349,103; 1,315,862; 1,349,104;
1,303,729; 1,303,730; 1,316,188

He details methods of underground and underwater wireless communications.
For a review, refer to _Electrical_Experimenter_, March 1919 and June 1919.

Rogers' methods were used extensively during the World War, and was
unclassified after the war. Supposedly, the government rethought this
soon after, and Rogers was convieniently forgotten.

The bottom line is that all antennas that are grounded send HALF of
their signal THRU the ground. The half that travels thru space is
quickly dissapated (by the square of the distance), but that which
travels thru the ground does not disapate at all. Furthermore,
the published data showed that when noise drowned out regular
reception, the underground antennas would recieve virtually noise-free.

IF you find this hard to believe, then refer to the work of the
man who INVENTED wireless: Tesla. Tesla confirmed that Rogers' methods
were correct, while Hertzian wave theory was completely "abberant".

----
 ET   "Tesla was 100 years ahead of his time. Perhaps now his time comes."
----

Newsgroup: sci.electronics
Document_id: 52446
From: w1gsl@athena.mit.edu (Steven L. Finberg)
Subject: New England Ham - Electronic Fleamarket Dates  ** 1 April update  **




New England Area Major Flea Market    ***  DATES  ***      1993        P 1 of 2
All events are Ham Radio/ Electronic related except ~_____~ 
*******************************************************************************
1993                                                    Contact          Source
*******************************************************************************

3 April Upper Saddle River NJ CRRC   9-3 sell @8     Jack W2EHD 201 768 8360 D

4 April Southington CT SARA @HS $20@6:3 $10@8:3 $3@9      N1GCV 203 621 6191 F

17 April Nashua NH NE Antique RC $5@8 $1@9 @ Res Ctr Church Ray 508 865 1290
 
18 April Cambridge MA       FLEA at MIT                    Nick 617 253 3776 F
               buy $2@9A  sellers $10/sp@7A $8in adv  $35 for season pass
               3rd Sunday Each Month April thru October   

18 April Webster MA ECARA @ Pt Breeze Rest $3 tables $10   Gary 203 974 2564 F

18 April Agawam MA HCRA @ Southwick Rec Ctr $3@9A     Bob W1ZGP 203 653 0715 F

23,24,25 April Dayton OH  adm $11  sell $30/50++       evenings 513 767 1107 F

2 May Yonkers NY  @Lincoln HS                       Otto WB2SLQ 914 969 1053 A

7-8 May Rochester NH Hoss Traders @FG ex13 off rt 16 $5 noon fri  WA1IVB sase

15 May N Smithfield RI RIFMRS @VFW Main St 8A        Rick K1KYI 401 725 7507  

16 May Cambridge MA       FLEA at MIT                      Nick 617 253 3776 F

16 May Pittsfield MA @Taconic HS Sell $5@7 Buy $2@8 Cliff W1SJV 413 743 3334  

21-22-23 May Rochester NY ARRL-NY Conv @ Monroe FG  Harold K2HC 800 724 8515 F

5 June S Burlington VT                             Mitch WB2JSJ 802 879 6589

6 June Newington CT @HS Flea                         Les KA1KRP 203 523 0453

12 June Bangor ME Pine St ARC @Hermon ES 146.34/94 8AM-$2 Roger 207 848 3846 

20 June Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F

17 July Nashua NH NE Antique RC $5@8 $1@9 @ Res Ctr Church  Ray 508 865 1290

17 July Union ME @ Fairground $3@7AM State Conv    Skeet KA1LPW 207 622 2915  

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LAST UPDATE 3-29-93 de W1GSL                                           P 1 of 2
*******************************************************************************
Additions/ Corrections  via Internet  w1gsl@athena.mit.edu
                            US Mail   W1GSL POB 82 MIT Br Cambridge MA 02139
                                      SASE for updated copy as issued.



1993                                                   Contact           Source
*******************************************************************************

18 July Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F
                   3rd Sunday Each Month April thru October   

24 July Manchester NH NHARA @HI 8A$4 NE DC 300Ts (no TG) WB1HBB 603 432 6011 F

8 Aug White Planes NY WECAfest                      Sarah N2EYX 914 962 9666 D

8 Aug Wellseley MA WARS+BARS @Babson College         Barry WN1N 508 877 4947 T

14 Aug St Albans ME  @ Snow Mobile Club             Hitch K1HHC 207 796 2282  

15 Aug Cambridge MA          FLEA at MIT                   Nick 617 253 3776 F

29 Aug Fall River MA BCRA                            Tom WA1LBK 508 674 4163 T+

11 Sept Windsor ME @ Fairground $3@7AM             Skeet KA1LPW 207 622 2915  

12 Sept Gaithersburg MD FAR @Mg Cty FG $5@6A- $7TG Nancy Drahim 703 691 0078 J

12 Sept S Dartmouth MA SE Mass ARA 8A-                Dan N1HCV 508 933 0678  +

19 Sept Cambridge MA         FLEA at MIT                   Nick 617 253 3776 F

19 Sept Sandy Hook CT Candlewood ARA               Harold KB1US              A

25 Sept Greenbush ME  WCSN/BARC @WCSN xmtr          Ed Cockburn 207 732 4366  

26 Sept Framingham MA @ HS $12@8 $5@9 $2@10          Barry WN1N 508 877 4947 F

26 Sept Yonkers NY Metro 70 ARC                     Otto WB2SLQ 914 969 1053 A

15,16 Oct Rochester NH Hoss Traders @FG ex13 off rt 16 $5 noon fri      K1RQG 

17 Oct Cambridge MA          FLEA at MIT                   Nick 617 253 3776 F

13 Nov Plymouth MA Mayflower RC @Mem Hall 9-3 sell@8   Jim NM1F 508 747 2224  
                   
14 Nov Branford CT SCARA @intrm sch                 Brad WA1TAS 203 265 9983 T
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LAST UPDATE 3-29-93 de W1GSL                                           P 2 of 2
Source F= Flyer  J= John Roberts list   A= ARRL list   WR NV 73 CQ QST = Mags
       T= tentative early info    D= W1DL      + = new info this month
This list has been compiled from many sources.  While we believe the info to 
be accurate the author can not be responsible for changes or errors.  
Check with the sponsoring organizations for more details. 
This list will be posted monthly to Usenet if additions have been made. 
Mailed copies are sent when additions are made.
*******************************************************************************
Additions/ Corrections  via Internet  w1gsl@athena.mit.edu
                            US Mail   W1GSL POB 82 MIT Br Cambridge MA 02139
                                      SASE for updated copy as issued.

Newsgroup: sci.electronics
Document_id: 52464
From: et@teal.csn.org (Eric H. Taylor)
Subject: Re: Electronic Tesla Coils

In article <1993Mar25.161909.8110@wuecl.wustl.edu> dp@cec1.wustl.edu (David Prutchi) writes:
>In article <C4CntG.Jv4@spk.hp.com> long@spk.hp.com (Jerry Long) writes:
>>Fred W. Culpepper (fculpepp@norfolk.vak12ed.edu) wrote:
>>[...]
>>A couple of years ago I put together a Tesla circuit which
>>was published in an electronics magazine and could have been
>>the circuit which is referred to here. This one used a
>>flyback transformer from a tv onto which you wound your own
>>primary windings. It also used 2 power transistors in a TO 3
>[...]
>10 years ago I built a 1'000,000 volt Tesla, and the thing was VERY
>spectacular, but besides scaring/amazing friends (depending on their
>knowledge of Science), and generating strong EMI, I never found anything
>useful that could be done with it ...  Is there any real-world application
>for Tesla coils today ?
>
>David Prutchi

First of all, realize that Tesla invented AC power generators, motors,
transformers, conductors, etc. Technically, *ALL* transformers are Tesla
coils.  In general though when someone refers to a Tesla coil, they mean
an "air core resonant transformer". The TV flyback version Tesla
coil (see the _Encyclopedia_of_Electronic_Circuits_ V3, 106-1 for
diagram) has NOT an air core. It is of a class of circuit called
"Oscillating Shuttle Circuit" (OSC). Generally OSC's are highly
efficient, but this version uses transistors and resistors,
which are very lossy devices. Typically Tesla used active
reactances instead of passive resistors, so that he could achieve
efficiencies of 99.5%, and better. The usual application of an air-core
resonant transformer, or of an OSC, is to produce strong EMI
for wireless broadcasts. How well do you think your computer
screen would work if we removed the HF HV Tesla (flyback) coil
from it? If we were to remove from our homes and industries all
Tesla coils, our lights would go dark, our cars would sputter
and die, our radios would go silent, our industries would grind
to a halt, and we would have to go back to using coal for heat,
gas for lamps, horses for transportation, steam for power, and
telegraph for communication. Is that real world enough for you???????

GET THE MESSAGE! WE WOULD NOT HAVE 1/100 THE CONVIENIENCES WE HAVE
TODAY IF NOT FOR TESLA. GIVE CREDIT WHERE CREDIT IS DUE!

If it had been up to Edison, we'd still be in the 19th century.
(flame me at your own peril. I'm very good at putting edison down).

----
 ET   "Tesla was 100 years ahead of his time. Perhaps now his time comes".
----

Newsgroup: sci.electronics
Document_id: 52717
From: jml@norman.vi.ri.cmu.edu
Subject: Re: Radar Jammers And Stealth Cars

Eric H. Taylor writes
> ... If you are determined
> to go faster, get an airplane. They dont have speed limits.

Just don't make a habit of buzzing your local airport at >200 knots
(250 knots if you're flying a jet).  :-)

Newsgroup: sci.electronics
Document_id: 52718
From: harpe@netnews.louisville.edu (Mike Harpe)
Subject: WANTED: Protel EasyTrax for the MAC

The title says it all.  Contact me via EMAIL if you would can help me out...

Mike Harpe
University of Louisville

P.S.  I KNOW IT IS DISCONTINUED.  I want someone who would like to sell
      an old copy.
-- 
Michael Harpe, Programmer/Analyst      Information Technology, Ormsby Bldg.
harpe@hermes.louisville.edu            University of Louisville
(502)588-5542                          Louisville, Ky. 40292
"He's not a man, he's a remorseless eating machine!" - The Simpsons

Newsgroup: sci.electronics
Document_id: 52719
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: What is Zero dB????

sehari@iastate.edu (Babak Sehari) writes:

>Similarly, people usually use dB for dBm. Another common mistake is spelling
>``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
>``Bell'' company, the mother of AT&T and should be capitalized.

Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the 
original Bell.  For example, SouthWestern Bell is a deciBell.

And the measure of current, Amp, is actually named after both the AMP company
and the Amphenol company.  Both companies revolutionized electronics by
simulatenously realizing that the performance of connectors and sockets 
were affected by the amount of current running through the wires.

The Ohmite company was the first to characterize resistances by numbers, thus
our use of the Ohms...


Alexander Graham Bell, actually, is where Bell came from...  



Actually, Bel refers

>                          With highest regards,
>                               Babak   Sehari.

>-- 
-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  | 
Pasadena, CA 91126 |   OS/2: The operating system of tomorrow, today.
+1 818 449 5457    |   

Newsgroup: sci.electronics
Document_id: 52721
From: blakey@ug.cs.dal.ca (Jason Blakey)
Subject: Site for projects

	Does anyone out there know of any ftp sites which deal with 
electronics projects, plans, etc?  Any response appreciated.:)
JB
-- 
 ............................................................................ 
                      Jason Blakey -> blakey@ug.cs.dal.ca 

Newsgroup: sci.electronics
Document_id: 52722
Subject: ACCESS BUS (was I2C bus)
From: srgxnbs@grace.cri.nz

From:	MX%"Andy.Macrae@Corp.Sun.COM"  6-APR-1993 06:48:34.96
To:	SRGXNBS
CC:	
Subj:	Re: I^2C bus and long haul serial (also Axlo

Return-Path: <Andy.Macrae@Corp.Sun.COM>
Received: from Sun.COM by GRV.GRACE.CRI.NZ (MX V3.1C) with SMTP; Tue, 06 Apr
          1993 06:48:29 +1300
Received: from Corp.Sun.COM (lemay.Corp.Sun.COM) by Sun.COM (4.1/SMI-4.1) id
          AA24280; Mon, 5 Apr 93 11:48:08 PDT
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          inbound)) id AA25933; Mon, 5 Apr 93 11:48:07 PDT
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          11:47:28 PDT
Date: Mon, 5 Apr 93 11:47:28 PDT
From: Andy.Macrae@Corp.Sun.COM (Andrew MacRae)
Message-ID: <9304051847.AA05710@grendal.Corp.Sun.COM>
To: srgxnbs@grace.cri.nz
Subject: Re: I^2C bus and long haul serial (also Axlo
CC: Andy.Macrae@Corp.Sun.COM
content-length: 693

In article <1pii04INNk6t@zephyr.grace.cri.nz> you write:
> Whats required to get onto the ACCESS bus? The nice thing about the
> i2c is that most i/o requires one 8 ... 16 pin DIL chip, ie its cheap
> and easy. Anyone can design a bus, trouble is most buses require a
> host of interface chips and often on-board intelligence.

Bruce,
	For the latest information on Access.Bus call the Access.Bus
Industry Group at (408) 991-3517.  Also, Sun will be hosting the next
meeting of the group on April 19th, here in Mountain View.  For some reason
I am not able to post to any newsgroups today, so please feel free to pass
this information on yourself as you see fit.

						Andrew MacRae


Newsgroup: sci.electronics
Document_id: 52723
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Re: Jacob's Ladder

g92m3062@alpha.ru.ac.za (Brad Meier) writes:

> Hi, I'm looking for a circuit, that is called a "Jacob's Ladder".
> This little box is usually seen in sci-fi movies.  It consists of 
> two curves of wire protruding into the air, with little blue sparks
> starting at their base (where the two wires are closer to each other),
> moving up the wires to the top, and ending in a small crackling noise. 
> 
> Could anyone supply me with the schematic for the innards of this box?
> 
> Thanks in advance
> Mike
> 
> (Please reply by email to g90k3853@alpha.ru.ac.za)
> 
> --
>  |  / |  | ~|~ /~~\  |  | ~|~ /~~\  |~~\  /~~\         The KnightOrc 
>  |/   |\ |  | |   __ |__|  | |    | |__/ |         g92m3062@hippo.ru.ac.za
>  |\   | \|  | |    | |  |  | |    | |  | |      "When it's over I'll go home,
>  |  \ |  | _|_ \__/  |  |  |  \__/  |  |  \__/    until then, I stay!" - Me

 
        I'd like any accumulated information on this as well please.
 
                Thanks.
 
_________________________________________    
    _____                                |
   |     |   |                           |
 =========== |    Baden de Bari          |
  | o   o |  |                           |
  |   ^   |  | baden@sys6626.bison.ca    |
  |  {-}  |  | baden@inqmind.bison.ca    |
   \_____/   |                           |
-----------------------------------------


Newsgroup: sci.electronics
Document_id: 52724
From: schellew@wu2.wl.aecl.ca (Wayne Schellekens)
Subject: WANTED: DRAM Controller for use with MC68HC16

For an upcoming project I want to use 4 Megs of DRAM configured as two 2
Meg banks of 16 bit data.  I was wondering if anyone out there knows of a
DRAM controller which will handle refreshing the data.  It's ok if the
controller doesn't handle bank switching - that part is easy.

The only controllers I know of are the ones out of the National
Semiconductor DRAM Management Handbook (1988 edition) eg. DP8429.  I would
like to know if another manufacturer produces one which may be easier to
implement in my circuit.

BTW, if anyone is wanting to hook up DRAM to a microcontroller, Dallas
Semiconductor makes a neat chip: the DS1262 Serial DRAM Nonvolatizer
Chip.  It uses the SPI (I2C) bus and refreshes/controls up to 16Mx1 of DRAM
memory.  It can use an external battery to refresh the DRAM when the
power is off.  Price is $11.75 from Dallas (quan 1).  I wish I could use
this chip but its maximum SPI clock rate is 1 MHz (too slow for me...).

Thanks in advance,

Wayne Schellekens
<schellew@wu2.wl.aecl.ca>
-- 
Wayne Schellekens, VE4WTS          Internet: schellew@wu2.wl.aecl.ca
AECL Research                         AX.25: VE4WTS@VE4KV.#WPG.MB.CAN 
Whiteshell Laboratories        Twisted pair: (204)753-2311 x2317

Newsgroup: sci.electronics
Document_id: 52725
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: HV diodes

In article <1pohuq$4sq@grouper.mkt.csd.harris.com>, wdh@grouper.mkt.csd.harris.com (W. David Higgins) writes:
|> I believe the only thing that needs correction, Mr. Vanderbyl, is your
|> attitude.

Nope, Mr. Myers has found the bad mistake and posted a correction, thank God.

|> Acting the child won't gain you any favors or make a

Who's acting?

|> positive impression with anybody.  Ghod knows you've make an impression
|> on me;  just not a positive one.

Oh no, I haven't impressed Mr. Higgins.


Newsgroup: sci.electronics
Document_id: 52726
From: rajan@cco.caltech.edu (Rajan Ranga)
Subject: An external timer

I was wondering if anyone knows of a chip that that is similar to
the internal timer 0 on the Intel 80C188?  I want a timer that has
a Maxcount A and B and the output should the same as Intel's timer.  I called
Intel and they told me that they don't make such a chip.  Any suggestions
are welcome.  Thanks in advance.

Rajan Ranga
E-mail: rajan@cco.caltech.edu

Newsgroup: sci.electronics
Document_id: 52727
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Re Using old databooks

In article <1993Apr3.110048.4636@hemlock.cray.com> kilian@cray.com (Alan Kilian) writes:
>> jeh@cmkrnl.com
>
>This is almost exactly the reason I keep only the latest databook around.
>Too many times last years books turn into three years ago and the data
>in them doesn't match the current production parts.
>TANSTAAFL,
>                             -Alan Kilian

BUT... If you are in the habit of trying to repair old and obsolete
machines, the old data books are a goldmine of information you can
not get anywhere else. If you are trying to find a modern replacement
for an obsolete part, the original specs really come in handy. Design
out of the new books but save the old ones (or donate them to a ham).

If anybody in Phoenix disagrees, I'll drive over and help them 'get rid'
of all their old data books.

John 
(450 data books and growing)




Newsgroup: sci.electronics
Document_id: 52728
From: timd@fenian.dell.com (Tim Deagan)
Subject: Homebuilt PAL (EPLD) programer?

Anyone know a reasonable circuit for programming PALs?  I am interested
in programming a wide range of EPLDs but would be happy with something 
that could handle a 22V10 or thereabouts.

Thanks in advance,
--Tim

---
{{{{{{{{{{{{{{{{{{{{{ timd@fenian.dell.com }}}}}}}}}}}}}}}}}}}}}}}}}}}}
             Rev. Tim Deagan - Official Obnoxious Poster
No one but me is responsible for anything I write, believe in or preach
* "It is difficult to free fools from chains they revere." - Voltaire *


Newsgroup: sci.electronics
Document_id: 52729
From: robert.desonia@hal9k.ann-arbor.mi.us (Robert Desonia) 
Subject: A/D board BUS SPEED probl


C >Hi:
C >I have a 486DX2-66MHz computer to use with an A/D board
C >for data acquisition on an AT bus...I'm having problems.
C >The AT bus runs at 12.5 MHz - correct?  So there should
C >be no bus speed conflict. But I read somewhere that the
C >new 486DX2-66 MHz CPU runs on a 33 MHz bus - is that for
C >the local bus or the AT bus also - if so then I have a problem.
C >^^^^^^^^^^^^^^^^^^^^^^^^^^^
C >When I run on non-turbo-mode the speed goes to 8 MHz and the
C >A/D doesn't work.  Please mail your views!  Thanks.
C >Vincent
C >cyl5@musica.mcgill.ca
C >

The STANDARD AT bus (ISA) runs at 8MHz, not 12.5 MHz, but some 
non-stnadard ISA buses do have higher clock rates, but be careful, since 
some boards don't work with faster than standard rates.  For instance, my 
486 has adjustable AT bus speeds, and my PAS16 audio card chokes when I do 
AD data acquisition with a bus speed faster than 10MHz.

The fact that non-turbo-mode speed A/D doesn't work is weird.  You may 
have a motherboard with a hardware 'bug'.  

33 MHz bus on the 486DX2 66 does refer to the local bus.  FYI: the AT bus 
operates asynchronously, and is linked to the local bus via a 'bus 
interface', which is one function that your 'chipset'.

-rdd

---
 . WinQwk 2.0b#0 . Unregistered Evaluation Copy
 * KMail 2.95d W-NET HQ, hal9k.ann-arbor.mi.us, +1 313 663 4173 or 3959
                                                     
----
| HAL 9000 BBS:  QWK-to-Usenet gateway  | Four 14400 v.32bis dial-ins    |
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| Call +1 313 663 4173 or 663 3959      +--------------------------------+
| Member of EFF, ASP, ASAD  * 1500MB disk * Serving Ann Arbor since 1988 |

Newsgroup: sci.electronics
Document_id: 52730
From: robert.desonia@hal9k.ann-arbor.mi.us (Robert Desonia) 
Subject: Re: PC Parallel I/O


R >>>JD> ALL PC parallel ports that are compatable with the IBM standard,
R >>>JD> including the original IBM adaptor, are bi-directional.

NOT ALL PARALLEL PORTS ARE BI-DIRECTIONAL WITHOUT MODIFICATION.

My experience with the standard old zenith parallel port in their 
original 286s proves that.  They had the input direction disactiviated by 
tieing them R/W select line of the circuit to Vcc.  To make it bi ( which 
I did ) I had to modify it by scraping off the trace and solder a jump to 
the proper location.  I thought that this was just lazy on the part of 
Zenith ( they were not Zenith-Bull Group at that time).

-rdd

---
 . WinQwk 2.0b#0 . Unregistered Evaluation Copy
 * KMail 2.95d W-NET HQ, hal9k.ann-arbor.mi.us, +1 313 663 4173 or 3959
           
----
| HAL 9000 BBS:  QWK-to-Usenet gateway  | Four 14400 v.32bis dial-ins    |
| FREE Usenet mail and 200 newsgroups!  | PCBoard 14.5aM * uuPCB * Kmail |
| Call +1 313 663 4173 or 663 3959      +--------------------------------+
| Member of EFF, ASP, ASAD  * 1500MB disk * Serving Ann Arbor since 1988 |

Newsgroup: sci.electronics
Document_id: 52731
From: laird@pasture.ecn.purdue.edu (Kyler Laird)
Subject: Re: Telephone on hook/off hok ok circuit

These circuits abound in most electronic project books.  If you're more
inclined to buy something, try Radio Shack.  I think they still have a
device that is designed to disconnect an answering machine when an
extension line is lifted.  It has LED indicators also. 

--kyler

Newsgroup: sci.electronics
Document_id: 52732
From: jeh@cmkrnl.com
Subject: Re: Police radar....Just how does it work??

In article <afgE02Wb3dVu01@JUTS.ccc.amdahl.com>,
 dws30@p1ps110cd.amdahl.com (David Sharpe) writes:
> There are a few more details to radar and some
> rumors that are not true.  A common one is that two beams are sent one
> reading the car speed and one the ground speed.  If this were true then
> calabration would be murder.  Hope this helps (Flame On)

Gee, then I guess the extra horn that's mounted in the floor of some SDPD cars,
firing at the ground at a shallow angle, is just for show, huh?

(For calibration, they simply turn off one horn or the other.) 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
Document_id: 52733
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Log/stereo high quality pot (hi-fi)

In article <1993Apr5.172839.22714@eng.cam.ac.uk> cmh@eng.cam.ac.uk (C.M. Hicks) writes:
>cobust@seagoon.ee.sun.ac.za (Cobus Theunissen) writes:
>
>>Hi there,
>
>>I am looking for a high quality log/stereo 10k pot for an audio 
>>preamplifier.  The design specifies Alps RKGA-2 10k AX2, but I cannot
>>find it anywhere!  Any suggestions?
>
>The best pots around (IMHO) are made by Penny & Giles in the UK. Their
>basic model has a solid brass case, and conductive plastic elements
>matched to 0.5dB across the whole rotation. The downside is that they
>cost upwards of 50 quid each :-(

The P&G pots are very good.  The Alps ones are usually carried by
the same folks who run the Audio Amateur magazine.  

I'll also recommend the Noble potentiometers, if you don't mind weird
metric sizes on everything.
--scott

Newsgroup: sci.electronics
Document_id: 52734
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Police radar....Just how does it work??

In article <1pqb8aINN9vg@hp-col.col.hp.com> cab@col.hp.com (Chris Best)  
writes:
> 
> The manual also got into the "cosine effect", wherein the motorist 
> always gets the benefit of the doubt (effectively).  Depending on
> relative directions of the radar gun and target car, the reading 
> will always be THE SAME AS or LOWER THAN the actual speed of the car.  
> Never higher.
> 
> And always remember that the cop doesn't even need radar to ticket you.
> His (her?) word as a skilled observer is enough. 

The father of a friend of mine is a police officer in West Virginia.  Not  
only is his word as a skilled observer good in court, but his skill as an  
observer has been tested to be more accurate than the radar gun in some  
cases . . ..  No foolin!  He can guess a car's speed to within 2-3mph just  
by watching it blow by - whether he's standing still or moving too!  (Yes,  
I realize that calibrated guns are more accurate than this, but . . .).   
His ability is not that uncommon among people who watch moving things for a  
living, I have heard . . ..

So what good is a radar detector except to give you a split second warning  
that the guy who just cut you off to pass the guy ahead and to your left  
is about to panic stop from 85 on a crowded freeway???

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
Document_id: 52735
From: wellison@kuhub.cc.ukans.edu
Subject: Re: Help with ultra-long timing

Thanks for the resposes as they were all good ideas and I am looking at using a
couple of the ideas. I recieved in the mail today the spec sheets on the mil.
spec version of Exar's XR-2240 timer/counter chip. It is stable down to -50 C
and sucks very little power. They show an application for a ultra-long time
delay (up to several years depending on the RC time constant). In this
application, they have two of them cascaded together. The reset and trigger
pins of both chips are tied together and the timebase of the second chip is
disabled. In this configuration, the output is high when the system is reset.
When triggered, the output goes low and stays that way for a total of 65,536 x
the timing cycle of the first chip. The total timing cycle of the two chips can
be programmed from To = 256 x R x C to 65,536 x R x C in 256 steps by selecting
any combination of the counter outputs to the timer output. The beauty of it
is, the timebase chip would only have to have a 100uF timing cap and a 391K
resistor for 39.1 seconds per timing cycle. So I can get a maximum of
2,562,457.6 seconds between timing cycles (39.1 x 65,536 or about 29 days !)
Of course, that's much more than I need (14 days). But the counter allows for
256 binary steps that can be selected for the output for the 'pellet puker'.
After the first 14 days and it trips, it would reset its self for the next 14
day timing cycle and so forth.

Power is still a problem though. A few ideas that you suggested was to bury the
electronics in a hole dug in the snow (as an insulator) and put the pellet
puker up on a tower above the estimated snow fall with a solar panel on it to
keep a charge on a lithium battery pack. I like that idea ;-) This thing has to
work for at least six weeks for three samples and the gas valves are 12 volts
to spit the pellets out onto the snow. Anyway, I ordered the XR-2240's to see
what I can do with them. Should be interesting (as long as I'm not the one that
has to go digging up the pellets in the middle of Antartica freezing my buns
off ;-)

Thanks again everyone...

-=-= Wes =-=-

Newsgroup: sci.electronics
Document_id: 52736
From: cph@dmu.ac.uk (Chris Hand)
Subject: Re: PC Based Layout Program

Frank Hielscher (hielsche@aragorn.CSEE.Lehigh.Edu) wrote:
: The PADS*.ZIP files contain subdirectories, and have to be unzipped
: via "pkunzip -d". Then an xcopy /s to three floppies creates the disks
: needed to do the install.

I'm still not sure how this is supposed to work, since the .ZIP files
took up about 2.5Mb, so it must be a tight squeeze on those floppies...

However, I managed to install PADS and I'm pretty impressed.  I created
a couple of schematics without problem, but whenever I try to 
create a PCB layout from one of *my* circuits (rather than the demos)
it doesn't work.  I'm wondering if maybe a file isn't where it should
be...

Can anyone who has a printed manual comment on whether the registration
fee is worth paying?


Chris


-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
Document_id: 52737
Subject: Re: Principle_of_the_Breathalyzer
From: srgxnbs@grace.cri.nz

In NZ apparently things like aftershave are also giving positive
readings


Newsgroup: sci.electronics
Document_id: 52738
From: rainer@spot.Colorado.EDU (Rainer Malzbender)
Subject: Re: HC11 blues -> no can find

In article <pat.734048757@fegmania.wustl.edu> pat@fegmania (Patrick Niemeyer) writes:
>I too had trouble finding hc11's when I looked for them a while back.
>I'd be interesting in hearing if anyone knows about their availability now...

The newest JDR Microdevices catalog has at least one variant of the HC11.

-- 
Rainer M. Malzbender
Fyzzicks, CU Boulder
(303)492-1366             

Newsgroup: sci.electronics
Document_id: 52739
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Oscilloscope triggering

In article <1993Apr5.120921.28985@dxcern.cern.ch>, jeroen@dxcern.cern.ch (Jeroen Belleman) writes:
|> In article <C4vs0G.5ux@murdoch.acc.Virginia.EDU> dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
|> >	Is it just me, or does anybody else out there NOT like digital
|> >scopes. My school has ...
|> >
|> >					David Jacobowitz
|> >					dgj2y@virginia.edu
|> 
|> Oh no you're not the only one. Analogue scopes give you (or me, at
|> least) a fair idea of what's going on in a circuit. Digital scopes
|> seem to have a habit of inventing a sizable part of it. E.g. even
|> when there are only a few samples per period, our HP54510A displays a
|> continuous waveform, complete with non-existing overshoots. I've
|> waded through lots of manual pages and menus, but I haven't found yet
|> how to turn this off. It doesn't show which points have actually
|> been measured, as opposed to those which have been interpolated,
|> either.

Perhaps you're using the wrong brand! (Sorry all HP fans, but I have
a hard time being convinced that their scopes match the rest of their
(excellent) gear).

One of the principal functions I look for when considering a DSO is
whether you can turn interpolation off. The other important feature
is to disable repetitive waveform acquisition i.e. being able to lock
the instrument into real time capture mode.

|> 
|> Secondly, I don't like menus. I want to see all common functions
|> with their own button. (You'll have guessed I love analogue Tek
|> scopes) I'd choose a knob with printed legend over an on-screen
|> display with up-down buttons right away. The single knob of most
|> digital instruments never seems to be connected to the right function
|> at the right moment.
|> 

I agree with you here. The only consolation is that manufacturers are
_beginning_ to pay attention to ergonomics when designing the menus.
However, to be fair, it seems that first time scope users (our students)
seem to adjust to menus easier than navigating around the twenty or
more knobs required of a "real" scope :-)

|> Last but not least, you never know if the waveform displayed is old
|> or recent, noisy or just incoherently modulated, heck, you don't
|> even know if it really looks the way it's displayed. Digital scopes
|> only show you a tiny fraction of what's going on. Most of the time
|> the're busy computing things.

This is one area that newer DSOs are addressing. I recently evaluated
the latest box from Tek - their TDS320 - which seems to be a worthy
alternative to a standard 100MHz analogue CRO. This instrument has
a 100MHz, 500Ms/s spec, meaning that it is _always_ in real time
capture mode. The pricing also matches equivalent analogue scopes in
the range. The downer is that the instrument uses menus again, but at
least they appear to be logically laid out.
|> 
|> There are only three situations for which I would prefer a digital
|> scope: Looking at what happened before the trigger, looking at rare
|> events, and acquiring the data to have my computer play with it.
|> 
|> 
|> Let's hope scope manufacturers are listening...
|> 
|> Best regards,
|> Jeroen Belleman
|> jeroen@dxcern.cern.ch

One more thing about the new, "simpler", front panels. These instruments
tend to use digital rotary encoders as knobs now. This is a vast improvement
over the old oak switch. The single most common cause of failure in our
scopes (other than students blowing up inputs!) is mechanical wear on these
switches. I look at the new panels as a great step toward increasing the
longevity of the instruments.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 52740
From: rob@dexter.psych.umn.edu (Robert Stephens)
Subject: Compressor Problem

I have a stereo compressor-limiter by 
Audio Logic (Model MT-66).  The gates work,
but the compressor seems to be gone on one
channel, and very weak on the other.  

I'll probably need an ocsilloscope to trace it
down (no pun intended), but if any one with
experience with this type of equipment could
point me in a certain direction as to where the 
circuit is most likely to fail, I'd sure appreciate it.


-- 
Robert C. Stephens		rob@dexter.psych.umn.edu		

Human Factors Research Lab
University of Minnesota


Newsgroup: sci.electronics
Document_id: 52742
From: neale@ee.rochester.edu (Reg Neale)
Subject: Pioneer Laser player

I'm trying to figure out how to operate a Pioneer Laserdisc LD-1000 that I bought at a surplus store. It is reputedly from some kind of computerised viewing
and/or ordering system. THere is what may be an HPIB connector on the back. When
I power it up, the front panel power light comes on, but no activity, and the
door doesn't open. Anyone have any experience with this unit or any ideas on how
to obtain documentation?

Newsgroup: sci.electronics
Document_id: 52743
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help with ultra-long timing

In article <1993Apr5.083324.48826@kuhub.cc.ukans.edu>, wellison@kuhub.cc.ukans.edu writes:
|> I have a project that was drooped in my lap that is somewhat a pain to design.
|> What I am looking for is a stable ultra-long solid state timer. What they want
|> to do is to place this thing on the Antartic ice shelf and measure the amount
|> of snow fall over a period of six weeks. Every two weeks, they want to trip a
|> selonoid to discharge different colored pellets by gas pressure out across the
|> snow. Then by digging down into the snow, the snow fall amount can be measured
|> as they come to the different color pellets.
|> 
|> The problem is trying to build a timer that would stand the cold (-40 degrees)
|> and a power source that wouldn't drain. I have looked at the XR-2204 timers and
|> the standard NE556 dual timers, but thier temp specs won't go that low. Also,
|> two weeks equates to 1,209,600 seconds per firing, which means one big timing
|> cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
|> 5 volts and are small in size. But again, the time of discharge at -40 or lower
|> degrees isn't linear. I was thinking of using several timers chained together 
|> to fire the selonid at the end of the timing period, but that blasted cold and
|> the drain on a battery over six weeks is the pain. One possibility would be to
|> use solar panels, but this is during the six month twilight. Anyone have any
|> good ideas ?
|> 
|> Thanks in advance...
|> 
|> -=-= Wes =-=-

Firstly, I would never consider trying to make a one-shot timer. Your 2F2 cap
will have been designed as a RAM battery substitute, rather than for use in
applications where you wish to drain the cap with a constant current. Their
performance, in some respects, is more akin to batteries than to a normal cap.
The other point is that big electro's are usually rated with -5%+20% tolerances,
so calculating exactly what capacitance you have (particularly when considering
the cold).

You should be looking at designing a micropower oscillator and divider chain,
that "rolls over" (from zero to maximum count, or vice-versa) once every
1,209,600 seconds. If you were to use something like a 110Hz clock, you would
need a divider chain of 2^27, to give an error of less than one percent in the
firing times over the six week period. Of course, you could trim the 110Hz
oscillator to give you exact time, but the likelyhood of the oscillator
remaining exactly constant at -40 is low anyway.

I would suspect that there would be far more battrey drain in firing the
solenoid than there would be in the timer circuit.

Caveat - I'm not experienced in low temperature electronics, so I can't
guarantee that this (or any other) approach is the best for inhospitable
conditions.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 52744
From: engp2254@nusunix1.nus.sg (SOH KAM YUNG)
Subject: Re: Protection of serial (RS232) lines

Martin John Gregory (mgregory@flash.pax.tpa.com.au) wrote:
: I've started to look at some devices doing serial data transmission
: over fairly decent distances in fairly noisy environments, and have
: seen a variety of schemes for protecting the RS232 transceivers (and
: the rest of the circuit) from transients on the serial lines.  I'm
: left wondering what is the best way of doing this?  How necessary is
: it?
: [stuff deleted]
: What is the wisdom on this out there?
: 
: Ta,
: 
: Martin.
: 
: 
From what I know, protection is necessary, esp. if you plan to route
the cables into an unknown environment (out of your control). Things
like accidental shorts between the signal lines and power cables, or
even lightning strikes are very likely and I don't think you like to see
the sight of your computer going up in smoke! [Even ethernet cards are
protected. I've looked at the one in my PC and the connector is
protected by a gas discharge tube!]

{But if you plan to use the serial cables for internal routings (i.e. in
controlled environments), it should be reasonably safe not to have
them.}

Suggestion: look in the RS data book. They have several RS232
transceivers that have overvoltage protection. Among them include the
LT1080, LT1081 and MAX250 and MAX251. The Maxims are suppose to be
electrically isolated ones but still need opto-isolators to work (don't
ask me why. I've never used them before.

Another alternative is an RS232 surge protector. Two are listed in the
RS catalogue. If you need additional info (i.e. stock nos.), just e-mail
me.

Soh Kam Yung,
engp2254@nusunix1.nus.sg

Newsgroup: sci.electronics
Document_id: 52745
From: john@gu.uwa.edu.au (John West)
Subject: Re: Protection of serial (RS232) lines

laird@stable.ecn.purdue.edu (Kyler Laird) writes:

>There is at least one optically-isolated RS-232 transceiver chip.  I
>don't remember where I saw it.

RS Components (they exist in Australia and the UK. Don't know about the US) have
little chips called Isolated MAX 250 and 251. They give you isolated RS-232 from
a single 5V supply. External components are 4 caps, 4 optoisolators, a diode,
and an isloting transformer. They go up to 19.2K baud..

John West
--
For the humour impaired: Insert a :-) after every third word

Newsgroup: sci.electronics
Document_id: 52746
From: rkim@mars.uucp (Richard H.S. Kim)
Subject: Need sources for HV capacitors.

Recently, my video monitor went dead, no picture, some low distorted sound.
I didn't hear the tell-tale cracking that indicated HV at work, nor are the
filaments at the far end of the tube glowing orange, just nothing.

On examining the power board, I noticed the largest capacitor with a very
bad bulge at the top.  Naturally, I want to replace it, but I can't find
any sources.

The electrolytic capacitor is 330 mF at 250WV.  It has radial leads, and is
roughly 1 1/2 inches long, 1 1/8" wide.  The dimensions are important since
the whole board fits in a metal cage, leaving little room.

Living in the Los Angeles area, I've been to numerous stores (Dow Radio,
All Electronics, ITC Elect, Sandy's, Yale Elect) with empty hands.

Can anyone suggest sources for high-voltage capacitors?  Mail order is 
fine, although I'd rather check out a store to compare the can.  I'm going
to try a video electronics store, hopefully they'll have HV caps.

(By the way, the monitor is a ATARI SC1224, Goldstar circuitry, Masushita
tube.  Anyone else had problems?)

Thanks in advance,
Rich K.

email>  rkim@opus.calstatela.edu

Newsgroup: sci.electronics
Document_id: 52747
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help with ultra-long timing

In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
|> (1) Don't use big capacitors.  They are unreliable for timing due to
|> leakage. 
|> 
|> Instead, use a quartz crystal and divide its frequency by 2 40 times
|> or something like that.
|> 
|> 1 MHz divided by 2^40 = 1 cycle per 2 weeks, approximately.
|> 
|> (2) I wouldn't expect any components (other than batteries or electrolytic
|> capacitors) to fail at -40 C (or -40 F for that matter either :) ).
|> The battery is going to be your big problem.  Also, of course, your
|> circuit shouldn't depend on exact values of resistors (which a crystal-
|> controlled timer won't).
|> 

... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
mechanically resonating device, extreme cold is likely to affect the
compliance (?terminology?) of the quartz, and hence its resonant frequency.

|> -- 
|> :-  Michael A. Covington         internet mcovingt@ai.uga.edu :    *****
|> :-  Artificial Intelligence Programs       phone 706 542-0358 :  *********
|> :-  The University of Georgia                fax 706 542-0349 :   *  *  *
|> :-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **


JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 52748
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: HC11 blues -> no can find

In article <pat.734048757@fegmania.wustl.edu>, pat@fegmania (Patrick Niemeyer) writes:
|> ree88132@zach.fit.edu (Keith Ledig) writes:
|> 
|> >was told by other people that it just takes a long time.  I heard
|> >rumors that the HC11 is very hard to get these days and is being
|> >replaced by the 711 series.  The sales person is trying to push
|> >the 711.  Can someone please tell me what is going on with these
|> >microcontrollers.  I can't seem to get a straight answer.
|> 
|> I too had trouble finding hc11's when I looked for them a while back.
|> I'd be interesting in hearing if anyone knows about their availability now...
|> 
|> Thanks,
|> Pat


The HC711 is an EPROM version of the HC11. Raw HC11 parts have factory set
ROM images, and as such are useless to the hobbyist. HC811 parts have
EEPROM, allowing for electrical erasure and reprogramming.

Some Motorola parts (such as the HC705K1) have EPROM, making them user
programmable, but come with options of either windowed or sealed. The
more expensive windowed packages allow multiple use, the plastic dip
varieties are one-time programmable, since there is no way of exposing
the EPROM array to light.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 52749
From: tg@cs.toronto.edu (Tom Glinos)
Subject: 12V to 3V and 48V at 3A

The subject line says it all. I'm working on a project
that will use a car battery. I need to pull off 3V and possibly
48V at 3A.

I have several ideas, but I'd prefer to benefit from all you
brilliant people :-)
-- 
=================
"Conquest is easy, control is not"	| Tom Glinos @ U of Toronto Statistics
[Star Trek TOS]   			| tg@utstat.toronto.edu
USL forgot this simple history lesson

Newsgroup: sci.electronics
Document_id: 52750
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: Help with ultra-long timing

Sounds like a job for a universal time reciever.  I don't know the
logisitics of the situation, but if you could just place a reciever in
snow and place the oscillator in a nice lab somewhere else, your
problems should be solved.
Just a suggestion.

Wayne Martin

Newsgroup: sci.electronics
Document_id: 52751
From: kthompso@donald.WichitaKS.NCR.COM (Ken Thompson)
Subject: Re: 68HC11 problem

mdanjou@gel.ulaval.ca (Martin D'Anjou) writes:
B
)>>>>>>>>> Votre host est mal configure... <<<<<<<<<<<<


)Bonjour Sylvain,
)	J'ai travaille avec le hc11 il y a 3 ans et je ne me souviens pas de toutes les possibilites mais je vais quand meme essayer de t'aider.

)	Je ne crois pas que downloader une programme directement dans le eeprom soit une bonne idee (le eeprom a une duree de vie limitee a 10 000 cycles il me semble). Le communication break down vient peut-etre du fait que le eeprom est long a programmer (1ms par 8 bytes mais c'est a verifier) et que les delais de transfer de programme s19 vers la memoire sont excedes. Normalement, les transferts en RAM du code s19 est plus rapide car le RAM est plus rapide que le eeprom en ecriture.

)	C'est tout ce que ma memoire me permet de me souvenir!

)Bonne chance,

Oh yeah easy for him to say!...

-- 
Ken Thompson    N0ITL  
NCR Corp.  Peripheral Products Division   Disk Array Development
3718 N. Rock Road  Wichita KS 67226   (316)636-8783
Ken.Thompson@wichitaks.ncr.com 

Newsgroup: sci.electronics
Document_id: 52752
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Wire wrap questions (again?)

In article <PASCAL.93Apr1160623@ap10.apd.cpg.sony.co.jp> pascal@apd.cpg.sony.co.jp (Pascal Goguey) writes:
>In article <7376@blue.cis.pitt.edu> macfitz+@pitt.edu (Mark D Fitzsimmos) writes:

> *After a considerable amount of research, review of discussions 
> *on this group, and mainly fruitless time on breadboards, I have 
> *decided that the path of least resistance for prototyping my (not 
> *necessarily someone else's) electronic designs is wire wrapping.  

>	I have no idea about what you want to do, but be careful :
>Wire wrapping increases a lot the wiring capacitance. That shouldn't
>be a problem for "slow" applications (i.e a few MHz), but as for
>quicker ones (around 30 / 40 MHz), I doubt that it can work.


	Fortunately, wire-wrapping is a better wiring technique than
most at high frequencies; Cray computers (up to the X-MP, at least)
all had wirewrapped backplanes.  Wirewrap gets into trouble at
much higher frequencies than any TTL can handle.  The 'increase'
of wiring capacitance is not really relevant (you have to use
transmission line techniques, and the capacitance is no problem).

> *1) Where can I get a decent wrapping tool?  I'd like to spend less 
> *than $150 for an AC powered unit including bit and sleeve.

>	Hand powered is the best. There are good AC powered ones,
>but rather expensive. A low-cost one doesn't work very well.

	Hand-powered is a terrible choice (IMHO) unless you are
a field maintenance person who will do maybe a dozen connections
at a time.  Your hands will cramp.  Battery-powered wire-wrap guns
are available in the $150 range, and so are the little
twiddle-stick manual types ($15).  For a modest project, of
a couple hundred connections, I'd prefer to borrow a professional
AC unit... or a pneumatic one.

	John Whitmore

Newsgroup: sci.electronics
Document_id: 52753
From: jkeais@ucssun1.sdsu.edu (keais j)
Subject: Re: Pioneer Laser player

In article <1993Apr6.005150.10250@ee.rochester.edu> neale@ee.rochester.edu (Reg Neale) writes:
>I'm trying to figure out how to operate a Pioneer Laserdisc LD-1000 that I bought at a surplus store. It is reputedly from some kind of computerised viewing
>and/or ordering system. THere is what may be an HPIB connector on the back. When
>I power it up, the front panel power light comes on, but no activity, and the
>door doesn't open. Anyone have any experience with this unit or any ideas on how
>to obtain documentation?

What you have is one of the LD players from a video game (Dragon's Lair,
Space Ace, etc). Call Pioneer Technicial Support 213-498-0300 (at least
that's the number I called them at) and ask for the LD-V1000 Interface
Guide. It shows how the parallel interface should be wired and the codes
for the commands (play, pause, reject, etc). The guide is mainly for hooking
the player to a computer, but with a little work, you could build a wired
controller.


Jim Keais        jkeais@ucssun1.sdsu.edu

Newsgroup: sci.electronics
Document_id: 52754
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Help with ultra-long timing

In article <1pqu12$pmu@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>|> (1) Don't use big capacitors.  They are unreliable for timing due to
>|> leakage. 

	True (especially for electrolytic capacitors at high temperature).

>|> Instead, use a quartz crystal and divide its frequency by 2 40 times
>|> or something like that.

>... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
>mechanically resonating device, extreme cold is likely to affect the
>compliance (?terminology?) of the quartz, and hence its resonant frequency.

	Low power quartz oscillators are usually 32 kHz (and THESE
have significant temperature drifts, which one doesn't often notice
while wearing the watch on one's wrist).  Low temperature sensitivity
is available in other crystal types, which unfortunately
are larger and higher frequency (1 MHz or so) and take more
battery power.  

	Programmable timers might be less accurate, but they
are more power-stingy than suitable crystal oscillators.

	John Whitmore

Newsgroup: sci.electronics
Document_id: 52755
From: wa2ise@cbnewsb.cb.att.com (robert.f.casey)
Subject: 2 level brightness Xmas light set (for Easter?


Yes, I know it's nowhere near Christmas time, but I'm gonna loose
Net access in a few days (maybe a week or 2 if I'm lucky), and wanted
to post this for interested people to save 'till Xmas.   :-(
Note: Bell Labs is a good place IF you have a PhD and a good boss, I
have neither.
--------------------------------------------------------------------------

Subject: Xmas light set with 2 levels of brightness

Another version of a variable brightness Xmas light set:
This set starts with a 2 blinker 35 bulb string.  

DIAGRAM:  orginal 2 way set

120v---+--b-*-*-*-*-*-*-*--!
       !---b-*-*-*-*-*-*-*-!
                           !
120rtn_____________________!

modified set for 2 level brightness:

                string 1
120v---------*-*-*-*-*-*-*-*--!
  \_10K_______*-*-*-*-*-*-*-*-!
    5w    !      string 2     !
          b   ________________!
120v rtn__!___!

             ^ Note: no mods to wiring to the right of this point.

Only one blinker is used.

Note that the blinker would not have as much current thru it as the
string 1 bulbs, because of the second string of bulbs in
parallel with it.  That's why the use of the 10K 5W resistor
here to add extra current thru the blinker to make up for the
current shunted thru the second string while the blinker is glowing
and the second string is not glowing.  When the blinker goes open,
this resistor has only a slight effect on the brightness of the
strings, s1 slightly dimmer, s2 slightly brighter.  
Or use a 3W 120v bulb in place of the 10K resistor if you can get
one.  Caution, do not replace with a standard C9 bulb, as these
draw too much current and burn out the blinker.  C9 = approx 7W.

What you'll see when it's working:  powerup, string 1 will light 
at full brightness, and b will be lit, bypassing most of the current 
from the second string, making them not light.  b will open, placing 
both strings in series, making the string that was out to glow at a 
low brightness, and the other string that was on before to glow 
at reduced brightness. 

Be sure to wire and insulate the splices, resistor leads, and cut wires 
in a safe manner!

Newsgroup: sci.electronics
Document_id: 52756
From: blakey@ug.cs.dal.ca (Jason Blakey)
Subject: FTP sites anyone?

    Hello netters:)  Does anyone out there know any FTP sites for projects,
plans, etc of an electrical nature?  

-Jason
-- 
 ............................................................................ 
                      Jason Blakey -> blakey@ug.cs.dal.ca 

Newsgroup: sci.electronics
Document_id: 52757
From: davidb@macadam.mpce.mq.edu.au (David Bull)
Subject: Intel RMX O/S Documentation Wanted


We've just been donated a large machine for use in our
robotics lab. This device is complete with a 286 based
controller, running the Intel RMX operating system.

Unfortunately, we don't have any documentation on RMX.

Can anybody out there in netland help?

Please reply via email; I don't regularly catch up with
the news.

Thanks,

David Bull

davidb@mpce.mq.edu.au



Newsgroup: sci.electronics
Document_id: 52758
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: What is Zero dB????

In article <sehari.733764410@vincent1.iastate.edu>, sehari@iastate.edu (Babak Sehari) writes:
|> In <C4truE.6AA@ms.uky.edu> msunde01@mik.uky.edu (Mark  Underwood) writes:
|> 
|> >I am somewhat familiar with the dB measurements as they apply to  
|> >electrical circuits - i.e. it is the gain of (for example) an amplifier  
|> >measured on a logarithmic scale.  However, this requires that you have a  
|> >reference value:  i.e the ouput is +20dB (e.g.) with respect to the input  
|> >signal.

<stuff deleted>

|> What you actually talking about here is dBm and not dB.  However, the terms
|> are used loosely by most people.  ``dBm'' is power with respact to 1mW, whereas
|> dB is a ratio.  Now, like these two English statement:
|>
|> 1.  I am doing well.
|> 2.  I am doing good.
|> 
|> Similarly, people usually use dB for dBm. Another common mistake is spelling
|> ``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
|> ``Bell'' company, the mother of AT&T and should be capitalized.
|> 
|>                           With highest regards,
|>                                Babak   Sehari.

Good gravy! Decibels are all *ratios.* The question that remains in
any ratio is the reference unit used. Sometimes, this will be a reference
power, such as 1 milliwatt (given a certain circuit impedance which
should also be included in the fine print or known, like 50 ohms
in an RF circuit of that impedance), leading to an accepted
notation of dBm. Maybe it might be dBV, disregarding the impedance of
the circuit and power developed, using 1 volt as reference *amplitude*
(rather than reference power). Or, it might have an arbitrary or omitted
reference that is not included in the notation, leading to just plain dB.
So. look at it this way--'dB' has an implied reference while notation
such as 'dBm' has an explicit reference.

For power:

  dB = 10*log( P(measured)/P(reference) )

For amplitude

  dB = 20*log( A(measured)/A(reference) )

'B' is for bel, which is a standard term for a log ratio to the base
10, named after Alexander Graham Bell. A 'deci' Bel is 1/10 of a bel.
It has nothing to do with the Bell Telephone company except for
the common founder's name. The small 'd'/large 'B' is per SI notation
convention. I don't know anyone that's been crucified for messing it up.

Common references for audio are:

	0 dBm = 1 milliwatt across 600 ohms
	0 dBV = 1 volt

	0 VU (a zero on the VU meter) = +4 dBm  (pro gear line level)
	0 VU = -10dBV	(consumer gear line level)


Often times, a power amp VU meter will be aligned using
the rated power of the amp as the 0 dB point. It is all
done to whatever reference is reasonable for the application
or moment.

Note that in a circuit with a given (and maybe unknown) linear
impedance, if the amplitude goes up so many decibels, the
power will also increase the same amount. This proof can be done
with the above two identities and ohm's law.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52759
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Flyback squeal in video monitors

In article <1993Mar31.204036.4359@ssc.com>, markz@ssc.com (Mark Zenier) writes:
|> Zack Lau (zlau@arrl.org) wrote:
|> : In sci.electronics, xhan@uceng.uc.edu (Xiaoping Han) writes:
|> : >In article <1993Mar24.163510.158@hubcap.clemson.edu> michaet@hubcap.clemson.edu (Michael D. Townsend) writes:
|> : >>brendan@macadam.mpce.mq.edu.au (Brendan Jones) writes:
|> : >>
|> : >>My mom's 25" Magnavox does this as well.  I put chewing gum all around
|> : >>the horizontal sync transformer so it wouldn't resonate the board as
|> : >>much.  Don't flame, it worked.  I realize that there is a more suitable
|> : >>substance available for this purpose, but I don't remember what and
|> : >>where it is.
|> : 
|> : >Adhesive silicon, from hardware store.
|> : 
|> : If it smells like vinegar, it may damage metal surfaces by
|> : promoting corrosion.  
|> 
|> Anybody tried Superglue (cyanoacrylate ?).  This should sneak
|> into the cracks better, and is stiffer than silicone.  

I've found this works pretty well on noisy laminated power
transformer cores and windings (the 60Hz kind). Likewise, if
anybody has tried this on a flyback I'd like to hear about it.

I would suspect it would not be as effective as it was on power
transformers as the material wouldn't damp as well--something
I suspect would be critical at the frequencies involved (in other
words, you want absorption rather than prevention which would be
real difficult at 15 KHz).

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52760
From: ph@gmd.de (Peter Hendricks)
Subject: Re: Wanted: A to D hardware for a PC

In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:

>	If you know much about PC's (IBM comp) you might try the joystick
>port.  Though I haven't tried this myself, I've been told that the port
>has built in A-D converters.  This would allow the joystick to be a couple of 
>pots.  If you could find the specs this might just work for you...

I guess 100k, connecting pins 1-3 (1x), 1-6 (1y), 9-11 (2x), and 9-13 (2y).

Or: Get an 8-bit DA-Converter (merely a couple of transistors and
Resistors) and an OpAmp to compare its output to the voltage you want to
measure, connect them to a spared printer port (if you have one), and do
the rest by software (stepwise refinement). The port addresses for your
printer ports are probably: &H378 (LPT1), &H278 (LPT2). This should work
well enough for your purposes.

Hope this helps

--
GMD,  Schloss Birlinghoven,  Postfach 1316,  D-5205 St. Augustin 1,  FRG

e-mail:  Peter.Hendricks@gmd.de			ph@zi.gmd.dbp.de
	 ph@gmd.de

Newsgroup: sci.electronics
Document_id: 52761
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Wanted: A to D hardware for a PC

>In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:
>
>>	If you know much about PC's (IBM comp) you might try the joystick
>>port.  Though I haven't tried this myself, I've been told that the port
>>has built in A-D converters.  This would allow the joystick to be a couple of 
>>pots.  If you could find the specs this might just work for you...

I believe that the "A-D converters" found on a joystick port are really
timers that tick off how long it takes an R-C circuit (the R being your
paddle) to charge up to something like 1/2 Vcc.  For games this works
pretty well, but you certainly wouldn't want to try to take lab
measurements off something as non-linear as that.

Hmm... I suppose you could linearize it in software, but the real problem
is that the precision of your measurement is no longer constant (higher
voltages would be more precise).

On the other hand, I could be wrong and perhaps the game card designers
splurged for the extra $.50 to make a cheap constant current source out of
an op amp.  But I wouldn't expect that...

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 52762
From: rooi@duteca3.et.tudelft.nl (Mark de Rooi)
Subject: Calculating a transformer - help needed

I want to convert a 500 Volt sinewave with frequency between 1 kHz
and 10 kHz, to a 10 Volt sinewave with the same frequency, by
means of a transformer. The secondary current will be .6 A (600 mA).

What kind of transformer should I use (ferrite?)
Can I buy one? If so, I need a partnumber and supplier
If I cannot buy one, how do I go about winding one myself?
What core do I use, how big must it be in order not to saturate,
what thickness copper wire, how many turns, etc.?

I know little about analog electronics, so I hope some kind
soul here will help me out.
Pointers to relevant databooks will also be highly appreciated.

Thanks,

Mark de Rooi
rooi@tpd.tno.nl

Newsgroup: sci.electronics
Document_id: 52763
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: HV diodes

In article <7480220@hpfcso.FC.HP.COM>, myers@hpfcso.FC.HP.COM (Bob Myers) writes:
|> > Nope.  The dag is on the outside of the tube, and is grounded.  The inside
|> > aluminization *is* the second anode, and is connected to the 'anode'
|> > suction cup.  This (with the glass of the tube in between) is a capacitor,
|> > and is used as the power supply bypass/filter for the HV supply.  Some
|> > smaller scope tubes don't have an aquadag coating on the outside.  If they
|> > are in mu-metal shields, you still have a capacitor.
|> 
|> Actually (and I think I said this in the original, but perhaps wasn't clear
|> enough) there is usually both an internal AND an external dag.  Of the two,
|> the internal dag is the more important; the aluminization of the back of the
|> phosphor is in most cases not adequate to guarantee connection to the anode
|> "button" (and in the case where the gun assembly includes an accelerating
|> electrode at anode potential, most definitely does not provide THAT 
|> connection).

Bob is indeed correct here in more than one way. A look in the old
RCA picture tube manual backs this up, as does SAMS Reference Data
handbook. The internal coating around the perimeter of the CRT
(not the aluminum or tin CRT face coating) is referred to as a
"dag" as well as the outer coating.

Thankfully, I didn't need to go to a f****** library to find it, either.
One sparkling water for Mr. Vanderbyl (no caffeine in that, is there).

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52764
From: dhembrow@eoe.co.uk (David Hembrow)
Subject: Re: SID chip to IBM system bus

Mr MC Howell (g90h6721@hippo.ru.ac.za) wrote:
: Please don't ask questions like "why don't you buy a soundblaster".  The
: answer is simple "Overpriced considering the sound quality".

Why not try one of the projects to build a DAC connected to the parallel
port as documented in some files which come with modplay ? These vary from
a 4 DAC design to a simple single DAC made only of resistors.-- 
David Hembrow                   EO Europe Ltd.,
email:  dhembrow@eoe.co.uk      Abberley House, Granhams Road,
                                Great Shelford, Cambridge CB2 5LQ, England

Newsgroup: sci.electronics
Document_id: 52765
From: leapman@austin.ibm.com
Subject: HeathKit/Zenith


Does anyone out there have the toll-free (catalog request and order line) for
Heathkit/Zenith?  Please post the number if you've got it!  Thanks.

Newsgroup: sci.electronics
Document_id: 52766
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Info on NEC 3D Multisync monitor

myers@hpfcso.FC.HP.COM (Bob Myers) writes:

> > I am looking for any info I can get on the NEC 3D monitor.
> > I know that it is a multisync but that is about all.
> > I plan on buying one second-hand in a while depending on its specs.
> > 
> > Does anyone know the min/max frequencies, whether it is interlaced, 
> > non-interlaced, or both, video compatability, etc?
> > I have seen a reference to it being .28 pitch with 1024 X 720 resolution 
> > and that it supports SVGA from one source and that it doesn't support 
> > SVGA from another source.  (Neither source seemed to have much reliable 
> > info so I don't want to take a guess.)
> 
> I'm at home right now, and so am away from my monitor files; the following
> is off the top of my head, subject to revision, worth-what-ya-pay-for-it
> sort of info.  If you don't hear from anyone who has spec sheet in hand,
> e-mail me and I'll look it up.
> 
> If I'm remembering correctly, the 3D is a 14" 0.28 mm pitch multisync that
> covers at least VGA (31.5 kHz horizontal, 60 Hz vertical) to 1024 x 768 
> 60 Hz (which is going to be about 48 kHz horizontal).  It may go somewhat
> higher than that on the horizontal, but you won't be happy with anything
> beyond 1024 x 768 on a 14" 0.28 tube; you probably won't be too thrilled
> with the 1024 x 768 on this tube, but it *will* sync up and display it.
> (I prefer at least a 16" 0.28 for this resolution.)  Since SVGA is 800x600,
> it'll do that too.  The horizontal range probably goes lower than 31.5, but
> I don't know if it goes all the way down to straight NTSC-rate TV (which need
> about 15.75 kHz sweep).  As far as "video compatibility" (if I'm reading
> the question right: it won't take anything but analog RGB inputs.  In other
> words, it has no way to decode NTSC or Y/C video inputs.  You would need
> some sort of board to to this conversion - like the sorts of things that 
> let you display NTSC on a VGA display.
> 
> Hopefully, now, I'll see this response of mine, and it'll remind me to
> look this stuff up and confirm it.  (Or force me to post a hasty retraction!)

Ok, I was under the impression that it accepted digital input.

I still don't know for sure if it accepts BOTH interlaced and 
non-interlaced as I have gotten conflicting info.

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 52767
From: cobust@seagoon.ee.sun.ac.za (Cobus Theunissen)
Subject: Wide band Analog time delay

Hi there,

I am looking for a wide band analog time delay (not phase delay)
variable from 200 microseconds to 2 milliseconds.

Please reply via email to rrc@firga.sun.ac.za

Newsgroup: sci.electronics
Document_id: 52768
From: jmichael@vnet.IBM.COM
Subject: Re: A to D hardware for a PC

If you can find a copy of "8088 Assembler Language Programming: The IBM PC"
by Willen and Krantz, 2nd ed. pub. by Sams, there is a discussion of the
game control adapter, monostable multivibrators, and conversion to other
uses, as well as an assembler program. If you need greater accuracy, there
is no reason you couldn't modify the approach to suit your needs.

Jim

Newsgroup: sci.electronics
Document_id: 52769
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Re: Homebuilt PAL (EPLD) programer?

In sci.electronics timd@fenian.dell.com writes:

>Anyone know a reasonable circuit for programming PALs?  I am interested
>in programming a wide range of EPLDs but would be happy with something 
>that could handle a 22V10 or thereabouts.

I too would be interested in ANY information on the subject of programing
PALS etc.....

  Better to know what your on about before you start something, I always
say. Often saves you a packet as well !!

Thanks in advance..

Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv     |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the Sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
Document_id: 52770
From: hanavin@huey.udel.edu (Chuck Hanavin)
Subject: Re: HeathKit/Zenith

In article <C52EGz.27t3@austin.ibm.com> $LOGIN@austin.ibm.com writes:
>
>Does anyone out there have the toll-free (catalog request and order line) for
>Heathkit/Zenith?  Please post the number if you've got it!  Thanks.

----------------------------------------------------
1-800-253-0570

Newsgroup: sci.electronics
Document_id: 52771
From: long@spk.hp.com (Jerry Long)
Subject: Re: Principle_of_the_Breathalyzer

william burchill (williamb@ee.ubc.ca) wrote:
: 	Does anybody out there know how the hand held breathalyzer used
: by our police works?  I would like to hear about this and the more
: general problem of detecting smells by machine.
: 
: Thanks, William.
: 
: williamb@ee.ubc.ca
: 

From what I have read about these little gadgets, it works on
a electrochemical galvanic principle. The sensing unit has a
chemical matrix which produces an electrical voltage proportional
to the amount of chemical compound it is designed for ... in this case
I believe it is the Hydroxyl group???  

I have also heard -  not tested :-)  - since common gasoline is also
a member of this Hydroxyl group, it will also cause a failing breathalizer
failure! Next time you get stopped for DUI, say you just siphoned gas from
your neighbors car (you know..... the Oklahoma credit card) and chances
are you won't get a DUI ticket!!!!


 
Jerry Long

long@spk.hp.com
****************************************
Disclaimer.... Opinions are my own and
do NOT reflect those of my employer.  
**************************************** 

Newsgroup: sci.electronics
Document_id: 52772
From: kenh@sail.LABS.TEK.COM (Ken Hillen)
Subject: RF data transmission

I need a off-the-shelf method of transmitting small amounts of data up to
300 feet.  The data is low speed and can be encoded as needed.  Low power
on the transmitting end would be a plus.  An FCC certified product would
be prefered.

If you have any pointers to products or companies I'd appreciate hearing from
you.

Thanks,
Ken

Newsgroup: sci.electronics
Document_id: 52773
From: massey@travis.llnl.gov
Subject: Re: Jacob's Ladder

In article <C4z6x7.16B@murdoch.acc.Virginia.EDU>, dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
> 	I've been wanting to build a Tesla coil for quite awhile now (
> who doesn't, right? ) and I thought it would be a good intermidiate
> step to build a JAcob's Ladder first.
> 	Well, I have been looking for a high voltage transformer that
> is reasonable inexpensive ( neon sign transformers cost mucho ).


In the past I've managed to buy used neon sign transformers from sign shops 
for about $20. Try calling around.


Warren N. Massey                                      Massey@Travis.LLNL.Gov
Lawrence Livermore National Laboratory   7000 East Ave., P.O. Box 808, L-495
Livermore, Calif. 94550  <<<My opinions are mine alone>>>      (510)422-1958

Newsgroup: sci.electronics
Document_id: 52774
From: pw@panix.com (Paul Wallich)
Subject: Re: Help with ultra-long timing

In <1pqu12$pmu@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <C513wI.G5A@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>|> Instead, use a quartz crystal and divide its frequency by 2 40 times
>|> or something like that.
>... Wouldn't a crystal be affected by cold? My gut feeling is that, as a
>mechanically resonating device, extreme cold is likely to affect the
>compliance (?terminology?) of the quartz, and hence its resonant frequency.
 
Yes, but in a fairly reproducible way. -40 is only a smidgen of the
distance to absolute zero. And in any case you're going to have to
borrow freezer space from a bio lab or someone to test/calibrate this
darling anyway. Btw, you're probably going to want those big capacitors
you found to fire the solenoid -- High current drain on frozen batteries
can be an ugly thing.

paul

Newsgroup: sci.electronics
Document_id: 52775
From: moffatt@bnr.ca (John Thomson)
Subject: Re: What is Zero dB????

Joseph Chiu (josephc@cco.caltech.edu) wrote:
: sehari@iastate.edu (Babak Sehari) writes:
: 
: >Similarly, people usually use dB for dBm. Another common mistake is spelling
: >``db'' instead of ``dB'' as you did in your article. See the ``B'' is for 
: >``Bell'' company, the mother of AT&T and should be capitalized.
: 
: Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the 
: original Bell.  For example, SouthWestern Bell is a deciBell.

Out of what hat did you pull this one?  dB is a ratio not an RBOC!        

: And the measure of current, Amp, is actually named after both the AMP company
: and the Amphenol company.  Both companies revolutionized electronics by
: simulatenously realizing that the performance of connectors and sockets 
: were affected by the amount of current running through the wires.

Sorry.  The unit for current is the AMPERE which is the name of a french-man
named AMPERE who studied electrical current.  The term AMP is just an abbreviation
of it.  The company AMP came after the AMPERE unit was already in use.
  
: The Ohmite company was the first to characterize resistances by numbers, thus
: our use of the Ohms...

I don't know about this one, but it doesn't sound right.
  
: 
: Alexander Graham Bell, actually, is where Bell came from...  
Well you got one thing right!
: 
: 
: 
: Actually, Bel refers
: 
: >                          With highest regards,
: >                               Babak   Sehari.
: 
: >-- 
: -- 
: Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
: MSC 380 - Caltech  | 
: Pasadena, CA 91126 |   OS/2: The operating system of tomorrow, today.
: +1 818 449 5457    |   

Greg Moffatt
Bell-Northern Research Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
Document_id: 52776
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr2.182216.28603@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:

|> |> Question 2:
|> |> 
|> |> 	If I am right about the doppler(if I spell it different every time,
|> |> maybe one will be right) effect, how does the radar get an accurate reading
|> |> when the car containing it is moving??  It would seem to me ( for all thats
|> |> worth) that it would need to be calibrated with the speedometer of the car
|> |> containing it??  I am fairly sure this isn't the case, so whats the deal??
|> 
|> Essentially, this is actually how it is done.  The radar gun is tied into
|> the speedometer of the car.

No, it is independent of the speedometer. The gun processes two doppler
returns--the speed of the car relative to the pavement and the speed
of the target, taking the difference between the two. Some guns with
a "moving mode" actually have a split beam with one beam aimed
preferentially at the pavement.

Car and Driver had a good article on traffic radar, but it was back in
1985. I used its contents and references to defend myself against a bogus
radar-measured ticket. It detailed "moving mode," which is easier to
defend against because of the increased amount of variables.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52777
From: scst83@csc.liv.ac.uk (Chris Smith)
Subject: Re: books/info on audio DSP ??

In sci.electronics,rec.audio David S. Rowell writes:

>I assume these are appropriate newsgroups for this question.  I am looking
>for a good book, articles, anything on audio DSP.  Theory is nice, but
>I'm really looking for something very much on the applications side.
>I want to look into it as my new hobby, so I need all the direction
>I can get.  Any comments would be welcome, too.

I'm looking to build a DSP for guitar processing. Hence lots of background
information would be really useful !

If anyone's got any info, could they email.....

Thanks in advance...

Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
Document_id: 52778
From: gerald.belton@ozonehole.com (Gerald Belton)
Subject: PC games (joystick) port

>Subject says it all - could someone tell me the pinout
>for a PC type analogue joystick port?

Joystick A:
1        +5 VDC
2        Button 1
3        X Axis
4        Ground
5        Ground
6        Y Axis
7        Button 2
8        + 5 VDC
Joystick B:
9        +5 VDC
10        Button 1
11        X Axis
12        Ground
13        Y axis
14        Button 2
15        +5 VDC

---
 . SLMR 2.1 . Soft judges make hardened criminals.
                                                                                 
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Newsgroup: sci.electronics
Document_id: 52779
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr2.182402.28700@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:

|> |> The 'beam' is split in two, with one beam aimed at the target car (sort of) and
|> |> the other at the ground.  The speeds of each are calulated for the final
|> |> number
|> 
|> Actually, this is true on the more expensive ones, but the cheaper ones
|> just read the speedometer.

I've never seen a speedometer-reading model. Are you sure? Who makes
them? Consider the difficulty of reading the speedo on various makes
of cars in use... I've seen single beam moving-mode and split beam
moving-mode.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
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   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52780
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: HV diodes

In article <1993Apr2.204617.14179@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
|> dtmedin@catbyte.b30.ingr.com (Dave Medin) writes:
|> >The CRT, in fact, does have an intentional built-in capacitor for
|> >its function just as IC's have built-in transistors, etc.
|> 
|> Gee, Mr. Myers, are we going to let this go without a CORRECTION?

Two things:

	1. Read your own posts. I was agreeing with Bob. No correction
	   needed.

	2. Don't quote stuff out of context.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52781
From: jsc52962@uxa.cso.uiuc.edu (Jeffrey S. Curtis)
Subject: Re: What is Zero dB????

moffatt@bnr.ca (John Thomson) writes:
}Out of what hat did you pull this one?  dB is a ratio not an RBOC!        
} [...]
}Sorry.  The unit for current is the AMPERE which is the name of a french-man
}named AMPERE who studied electrical current.  The term AMP is just an abbreviation
}of it.  The company AMP came after the AMPERE unit was already in use.
} [...]
}I don't know about this one, but it doesn't sound right.
} [...]
}Well you got one thing right!

Hello? John? Oh, nevermind...

Jeff
-- 
Jeffrey S. Curtis sidewinder@uiuc.edu | "Resplendent in full regalia, they
 The Power of 37  free2207 at uiucvmd | revel in their role as self-appointed
 Sony - Phase Linear - Sanyo - Sennet | critics of the establishment..."
 Jensen - Polk - StreetWires - Proton |   -- INXS _Welcome to Wherever You Are_

Newsgroup: sci.electronics
Document_id: 52782
From: caryd@a.cs.okstate.edu (CARY DAVID ALLEN)
Subject:  Self-modifying hardware

Permit me to quote fragments of 
praetzel@sunee.uwaterloo.ca's article
out of context.

-Newsgroups: sci.electronics,comp.lsi.cad
-From: praetzel@sunee.uwaterloo.ca (Eric Praetzel)
-Date: 10 Feb 93 15:46:41 GMT

-  Currently the XNF format is propierty and I know of at least on person at
-a university who was able to get it after signing a non-disclosure agreement.
-The Xilinx-bit map format is pretty well top secret.  I would love to know it
-because then you could make self_modifying_hardware  ;-)  As it is I had to
-reverse eng. the Xilinx tools to dump the bit map to the FPGA because it only
-runs on the computer with the hardware key.

self-modifying hardware could be *very* interesting --
 computers that could write thier own programs (assemblers, compilers)
were an immense breakthrough from calculators that couldn't.

-  I eagerly await a programmable gate array which uses a PD format and does
-not cost your first born to program.  Till then we will keep on reverse
-engineering whatever we can.  As it is one company that I worked at has gone
-under.  FPGAs are what they needed to make their product competitive.  They
-could not afford them.  In the end you could say that they could not afford
-to not use them but the management discovered that too late. 
-   - Eric 

my condolences.

i can't even imagine what i could do with self-modifing hardware.
i *can* imagine self-modifying software,
and even though *all* my teachers say that's BAD, even Worse than GOTO,
check out what the experts *used* to say about self-modifying code:
(he uses "orders" rather than "opcodes")


"On the Principles of Large Scale Computing Machines"
by Goldstine and von Neumann,
collected in 
_John von Neumann: Collected Works, Vol. V_
reprinted here with absolutely no permission from anyone.
"We plan... to have a full size (40 binary digit) word hold
either contain
1 full size number (... equivalent to 12 decimal digits,
but we will use the first binary digit to denote the sign)
or two (20 binary digit) orders.
....
	It should be added that this technique of
automatic substitutions into orders,
i.e. the machine's ability to modify its own orders
(under the control of other ones among its orders)
is absolutely necessary for a flexible code. Thus, if
part of the memory is used as a "function table", then
"looking up" a value of that function for a value of the 
variable which is obtained in the course of the computation
requires that the machine itself should modify, or
rather make up, the reference to the memory in the order which
controls this "looking up", and the machine can only make this
modification after it has already calculated the value of the 
variable in question.
	On the other hand, this ability of the machine to modify its
own orders is one of the things which makes coding
the non-trivial operation which we have to view it as."

david cary, tenor, e- and comp. engineering (finger caryd@a.cs.okstate.edu).
227 S. 163 E. Ave, Tulsa, OK  74108-3310, USA, Sol 3, Universe v. 1.2

-- 
david cary, tenor, e- and comp. engineering (finger caryd@a.cs.okstate.edu).
227 S. 163 E. Ave, Tulsa, OK  74108-3310, USA, Sol 3, Universe v. 1.2

Newsgroup: sci.electronics
Document_id: 52783
From: rsd@sei.cmu.edu (Richard S D'Ippolito)
Subject: Re: What is Zero dB????


In article <1pkveuINNduk@gap.caltech.edu>, Joseph Chiu writes:

> The Ohmite company was the first to characterize resistances by numbers, thus
> our use of the Ohms...


Yeah, right.  And the company was started by George Simon Ohmite.

Rich

Newsgroup: sci.electronics
Document_id: 52784
From: jgd@dixie.com (John De Armond)
Subject: Re: Help with ultra-long timing

wellison@kuhub.cc.ukans.edu writes:

>I have a project that was drooped in my lap that is somewhat a pain to design.
>What I am looking for is a stable ultra-long solid state timer. What they want
>to do is to place this thing on the Antartic ice shelf and measure the amount
>of snow fall over a period of six weeks. Every two weeks, they want to trip a
>selonoid to discharge different colored pellets by gas pressure out across the
>snow. Then by digging down into the snow, the snow fall amount can be measured
>as they come to the different color pellets.

>The problem is trying to build a timer that would stand the cold (-40 degrees)
>and a power source that wouldn't drain. I have looked at the XR-2204 timers and
>the standard NE556 dual timers, but thier temp specs won't go that low. Also,
>two weeks equates to 1,209,600 seconds per firing, which means one big timing
>cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
>5 volts and are small in size. 

Why are you fooling around with analog for this job?  A single chip
micro and a crystal will do the job reliably and easily.  An 8748 only
costs about $5.  That and a $1 crystal and you're in business.  Embed
the whole thing in a foam insulated blanket, power it from a solar cell,
use the excess power to heat the assembly during the day and rely
on the insulation to hold the heat during darkness.  If you don't want
to try thermal management, contact someone like ICL and have them cut
you a special low temperature crystal.  It'll cost at most $20.

If you use a single chip micro, you're looking at a parts count of 
maybe 7.  A processor, a crystal, two caps on the crystal, a power FET
to fire the solenoid a flyback diode and a battery.  This is fewer parts than 
you can build an analog timer for and is infinitely more reliable.  Add
a power zener diode (for heat) and a solar cell and the parts count
screams up to 9.

PD assemblers are available for all the common single chip micros.  This
application is so trivial you could even look up the op codes in the 
programmer's guide and create the binary with a hex editor.

John
-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine(TM) | Interested in high tech and computers? 
Marietta, Ga                         | Send ur snail-mail address to 
jgd@dixie.com                        | perform@dixie.com for a free sample mag
Need Usenet public Access in Atlanta?  Write Me for info on Dixie.com.

Newsgroup: sci.electronics
Document_id: 52785
From: jmichael@vnet.IBM.COM
Subject: Radar Detector DETECTORS?


They detect the oscillator operating in the detector. Saw a story about
their use in Canada. Now don't go putting oscillators in your cars... :-)

Newsgroup: sci.electronics
Document_id: 52786
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Voltage Multiplier Problem.

Hi,

   I've just built a valve preamp and use a diode/capacitor
voltage multiplier to step the 12vAC supply voltage up to approx 
260vDV. As the load resistance increases, the RC constant decreases
and hence the output voltage drops. I need as high an output
voltage as possible. (about 260v).
  The circuit consists of seven voltage multiplier stages
(ie 14 diodes and 14 capacitors) each capacitor develops about 38v
across them, and I take the output from across seven capacitors=260v.
  Each capacitor is 100mfd at 68v.
 If I increase each of the capacitors rating (220-470mfd), that will
increase the RC constant, and hence alleviate some of the problem.
These capacitors are going to be a little expensive as I need 14 of
them, So:

1. What would happen if I connected a 470mfd at 400v capacitor in parallel 
with the output (and hence in parallel with the seven 100mfd capacitors)?
  Will it, as I assume, increase the C in circuit and hence increase
the RC time constant? If it does, and my output voltage becomes more
stable by doing this, then I will have killed two birds with one stone...
as I am experiencing some 50Hz ripple (and hence amp hum), and this new
capacitor will 'smooth' this out.

and
2. Can anyone recomend a suitable value for an inductor (choke) to
be placed in the output line of the power supply to filter out
the 50Hz mains hum. Lowest resistance possible !

  I've not got my preamp with me at the moment because it is TOO MUCH
of a distraction.... (I'm at university and I've got to get my 
dissertation finished in two weeks !!!!!!!) hence I'm mailing not
playing with my solderoing iron (it'll be cheaper too in the long
run... especially if 14 new large capacitors don't work as planned!)

Email please.... Can't always read the net.....

Thanks in advance..


Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
Document_id: 52787
From: koops@gaul.csd.uwo.ca (Luke Koops)
Subject: Speaker design software?

Hi.  I'm looking for software to aid a friend of mine with designing speakers.
Does this type of software exist?  If anyone can point me toward a shareware or
freeware product with this description, that would be ideal.

...Steve van der Burg (using a friend's account)

(p.s. Excuse the terseness of the message;  I'm having difficulty stringing
readable sentences together today, for some reason.)

-- 

				-Luke Koops


Newsgroup: sci.electronics
Document_id: 52788
From: jmichael@vnet.IBM.COM
Subject: Electric power line "balls"

Power lines and airplanes don't mix. In areas where lines are strung very
high, or where a lot of crop dusting takes place, or where there is danger
of airplanes flying into the lines, they place these plastic balls on the
lines so they are easier to spot.

Newsgroup: sci.electronics
Document_id: 52789
From: behnke@FNALF.FNAL.GOV (M.L. 'Broomen' Behnke)
Subject: Re: Electric power line "balls"

In article <1993Apr6.203237.20841@eagle.lerc.nasa.gov>, fsset@bach.lerc.nasa.gov (Scott Townsend) writes:
>I got a question from my dad which I really can't answer and I'd appreciate
>some net.wisdom.
>
>His question is about some 18-24" diameter balls which are attached to
>electric power lines in his area.  He's seen up to a half dozen between
>two poles.  Neither of us have any experience with electric power distribution.
>My only guess was that they may be a capacitive device to equalize the
>inductance of the grid, but why so many between two poles?.
>
>Anyone know what they really are?  Is there a related FAQ for this?
>Is there a better group to submit to?
>
>We'd both appreciate some enlightenment.
>

 The balls are used to reduce the amplitude of oscillations of the wire during
periods of high winds.  I've seen what looks like paint cans filled with
concrete used for the same purpose.
Mike Behnke             | Senior Tech/Advisor | Quid est illuidin aqua??
Fermi Nat Accel Lab     | Equipment Suuport   |
Batavia, Il.            | Computing Div       | PISTRIX!!  PISTRIX!!
BEHNKE@FNALF.FNAL.GOV   |                     |

My opinions are my own, not of the lab. So, if you don't like them, call

1-800-UWH-INER

Newsgroup: sci.electronics
Document_id: 52790
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Oscilloscope triggering

In article <C4vs0G.5ux@murdoch.acc.Virginia.EDU>, dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
|> >>Can someone out there explain exactly what the 'trigger'
|> >>feature found on oscilloscopes does?
|> >
|> 	{ lots og good explanation deleted}

<lots more deleted>
|> 	Is it just me, or does anybody else out there NOT like digital
|> scopes. My school has some beauutful 100Mhz HP that are digital with
|> all the bells and whistles, including soft-keys, which I think are a
|> loveley touch. ( that is, software keys. ) You don't forget that you
|> are dealing with a computer. Those scopes even with all their
|> neatness, still make the ickyest looking waves. Lotsa features, but
|> ugly output. And those are the best digitals I have ever seen. I've
|> seen a lot of cheaper digitals and they look terrible.

I think the hangup with digital scopes is that you have to know so much
more about them and how they work on a scope-by-scope basis, and
some of the functions are typically presented, in my opinion,
in a counter-intuitive fashion (HP has made some strides in their
54600 series, IMO). Automatic setups are fine for simple,
repetitive waveforms, but can give you some crazy results on more
complex events where you need to understand how the scope is
actually measuring/processing the event. For example, is the scope
in "equivalent time" or in "real time" sampling mode (equivalent time
being a mode where samples are built-up slowly by adding a delay to
the trigger event each sweep)? What was the scope's actual sampling
rate at the time? How is the data being massaged after capture but
before display, etc. One common misconception is the speed of the scope.

Is the HP scope you're using really a 100 MHz scope? Or is it a 20 MHz
sample rate scope (~5 MHz single shot significance) whose front
end including S/H can support 100 MHz waveforms (important for
equivalent time sampling)? The 100 MHz input in this case really
only helps you when your waveform is repetitive, or on a single
sample, when you get lucky and hit a transient event during a sample time.

So, there are a lot more variables in understanding how to get
useful information from a digital scope. I prefer an analog scope for
general use and the digital for events where I need storage for
later analysis or comparison, when the event is within the capability
of the scope. Now, for the price of true 100 MHz digital scopes to
fall...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52791
From: heinboke@tnt.uni-hannover.de (Andreas Heinbokel)
Subject: LOOKING for AD PC-Board

This is for a friend of mine. Please send answers directly to him (E-Mail
adress see below )!


HIGHSPEED  ANALOG-DIGITAL PC-BOARD

Hello LAdies and Gentleman !

I am looking for a highspeed A/D PC-Board with a sampling rate above 250 MHz an a
resolution of 8-bit. The sampling rate can be arranged by an interleave mode where
the time equivalent sampling yields 2, 4 or 8 times higher sampling rate than
the A/D-Converter uses in non interleave mode.

The board must content an A/D-Converter similar to Analog Devices AD 9028 or 
AD 9038 or if available a faster on.

If you a PC-Board (16-bit slot, ISA) with this specification or better, please
send me an EMail

hansch@cdc2.ikph.uni-hannover.dbp.de

or a Telefax to: ++49 / 511 / 7629353


Thanks in advance for your help !

Sincerely

     Matthias Hansch
     IKPH, University of Hannover, Germany



---

Andreas Heinbokel

heinboke@tnt.uni-hannover.de

*** ... all wisdom is print on t-shirts ***


Newsgroup: sci.electronics
Document_id: 52792
From: gmc@cthulhu.semi.harris.com 
Subject: Re: What is Zero dB????

In article <1993Apr6.132429.16154@bnr.ca>
      moffatt@bnr.ca (John Thomson) writes:

 >Joseph Chiu (josephc@cco.caltech.edu) wrote:
 >
 >: Thus, a deciBell (deci-, l., tenth of + Bell) is a fractional part of the
 >: original Bell.  For example, SouthWestern Bell is a deciBell.
 >
 >Out of what hat did you pull this one?  dB is a ratio not an RBOC!
 >
 >: And the measure of current, Amp, is actually named after both the AMP company
 >: and the Amphenol company.  Both companies revolutionized electronics by
 >: simulatenously realizing that the performance of connectors and sockets
 >: were affected by the amount of current running through the wires.
 >
 >Sorry.  The unit for current is the AMPERE which is the name of a french-man
 >named AMPERE who studied electrical current.  The term AMP is just an abbreviation
 >of it.  The company AMP came after the AMPERE unit was already in use.
 >
 >: The Ohmite company was the first to characterize resistances by numbers,
 >: thus our use of the Ohms...
 >
 >I don't know about this one, but it doesn't sound right.
 >
 >:
 >: Alexander Graham Bell, actually, is where Bell came from...
 >Well you got one thing right!
 >:

Actually, I think J. Chiu knows the score and is just being
silly. However, "decibel" is in fact 1/10th of a bel. He is
right on that one, but I don't know if it was accidental or not.

Strictly defined, a bel is the ratio of the log of two power levels,
and a decibel is 1/10th of a bel so you have 10X decibels for every bel,
hence bel=log(P2/P1) and decibel=10Xlog(P2/P1).

The bel, ohm, volt, farad, ampere, watt, hertz, henry, etc. are
all named for pioneers in the field. It's a traditional and fine
way to honor researchers who discover new knowledge in a new field.
Hertz was one of the most important of the early electronics explorers,
but had been left out in having a term or unit named after him
until recently, (1960's, prior to that what is now a hertz was a cps.)
All the other units were defined many decades earlier.


 


-- 
----------------------------------------------------------------------




----------------------------------------------------------------------


Newsgroup: sci.electronics
Document_id: 52793
From: cab@col.hp.com (Chris Best)
Subject: Re: Police radar....Just how does it work??

I've seen several references to split- or separate-beam radars, which I
claimed didn't exist.  Gotta eat some crow here - I wasn't aware of them.
All I really knew was that it can be done with one beam.

I believe the rest of what I said is accurate, though.

Mmmmmmm....crow.... (oops-wrong group)

Newsgroup: sci.electronics
Document_id: 52794
From: ragee@vdoe386.vak12ed.edu (Randy Agee)
Subject: Radar detector DETECTORS?

Here's one I hope some knowledgeable readers will make a comment or
contribution to:

In the State of Virginia radar detectors are illegal, period.  If
you are caught with one it will be confiscated on the spot and will
not be returned until after you appear in court and pay your fine. 
The fine for having a radar detector accessible in a motor vehicle
(even if it is not on) is $250.00.  Sorry, tourist, ignorance of
the law is no excuse - they will get you too!

It used to be that the only way the law could be enforced was for
an officer to actually see the radar detector.  Not any more!  Many
law enforcement agencies are now using radar detector detectors. 
Right, a super sensitive receiver that is capable of picking up RF
from the radar detector itself.  My first reaction was "no way!" 
But, guess again, these little buggers really work and the police
are writing citations right and left for people using radar
detectors.  One news story quoted an officer as saying that he had
found the radar detector in all of the cars he stopped except one,
and he could never figure out where it was - but he knew it was
there.  This tends to make one assume there are few false arrest.

Now, before I get flamed, please understand that I do drive at or
near the speed limit.  I do not need a radar detector to keep me
from getting a speeding ticket.  But, I do like to know when my
speed is being clocked or a speed trap is functioning.  My radar
detector now stays locked in my trunk when I am in Virginia (which
is what they want - and yes, what the law says, and I intend to
obey the law!) and is only used in states where it is legal.

For my fellow hams, I am not a microwave person - my mind only
works in the HF spectrum between 10 and 80 meters.  Microwave
enlightment may be necessary.

So, the questions are -
  What do the radar detector detectors actually detect?
  Would additional shielding/grounding/bypassing shield stray RF generated by
  a radar detector, or is the RF actually being emitted by the detector
  antenna?
  Are any brands "quieter" than others?

==============================================================================
Randy T. Agee - ARS WB4BZX       | At some point, you probably pondered The 
P.O. Box 2120 - 20th floor       | Meaning of Life, and you came up with a 
Virginia Department of Education | satisfactory answer, which has or has not
Richmond, VA 23216-2120          | stood the test of time, or you shrugged
Phone (804) 225-2669             | mightily, muttered "Beats the heck out of
ragee@vdoe386.vak12ed.edu        | me," and ordered a cheeseburger.
=============================================================================
 

Newsgroup: sci.electronics
Document_id: 52795
From: scst83@csc.liv.ac.uk (Mr. C.D. Smith)
Subject: Re: Why is telephone audio 300-3000 Hz?


>> telephone systems have the capability of a passband of 30hz to 4Khz.
>> The reason they do not implement this is: It is not backward compatable
>> to every telephone system.  In addition, the most effecent mix of 
>> electrical effecency, and intelegability closly mateches a 300hz-3khz
>> passband.
>
>Close, but no banana (to paraphrase Garfield)...
>The reason 300-3300 Hz is used is that voice channels used to occupy
>4kHz bands when multiplexed on a trunk line. Therefore, 300Hz at the
>bottom, and 700Hz at the top of this band were filtered to minimise
>interference with the next band.
>
>Nowadays, digital trunks have made this less relevant, but the phone
>companies still see no reason to improve quality (especially for free!).
>Therefore, digital "chunk of a trunk" segments still have a guaranteed
>bandwidth of only 4kHz (so they can carry the equivalent of one analog
>line) at the clock rate of a standard PCM T1 or E1 digital trunk.
>
>It's all historical...


Here in the UK, the bandwidth restriction apparently only apply to 
local lines.. ie those used by the average domestic client. Private
lines which are run from the local exchange to the leasing client are 
usually capable of a higher bandwidth if the exchange is digital.

Don't quote me on that..... But I think I remember a BT engineer 
saying something to that effect when I was doing some work
shadowing a few years ago.

Byeeeee !


Chris ;-)

  +====================================================================+
  |Name : Mr Chris Smith       |     Twang on that 'ole guitar !       |
  |Addrs: scst83@uk.ac.liv.csc |                                       |
  |Uni  : Liverpool University |Quest: To build more and more hardware |
  |Dgree: Computer Science     |                                       |
  +====================================================================+

 "What ever the sun may be, it is certainly not a ball of flaming gas!"
  -- D.H. Lawrence.

 * All views expressed are my own, and reflect that of private thought. *

Newsgroup: sci.electronics
Document_id: 52796
From: rivero@sol.cie.unizar.es
Subject: Video IO ideas?

Have anyone some idea about how to build a cheap, low
resolution (or high :-) video projector... 

(example: a LCD and an slide projector)
.



Newsgroup: sci.electronics
Document_id: 52797
From: linnig@m2000.dseg.ti.com (Mike Linnig)
Subject: Re: books/info on audio DSP ??

In article <C52DsD.7pB@compsci.liverpool.ac.uk> scst83@csc.liv.ac.uk (Chris Smith) writes:

> I'm looking to build a DSP for guitar processing. Hence lots of background
> information would be really useful !
> 
> If anyone's got any info, could they email.....

Well, I'm not sure I'd use this to process a guitar but there was a audio
filter DSP construction article in the Sept 92 issue of QST magazine (Ham Radio
oriented).  The DSP is available in kit form for about $120.

This particular DSP filter was targetted toward processing audio to remove
noise (static).  I built it and it really works well.  The source code is
available too.  It makes a noisy audio signal much easier to hear.  Note that
this is for communication applications and is not "high fidelity".



--
- - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - - - +
Mike Linnig, Texas Instruments Inc. | 97.43% of all statistics are made |
Phone: (214) 575-3597  CALL: N5QAW  | up; most of them (83.6 percent)   |
Internet: mike.linnig@dseg.ti.com   | are wrong.                        |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


Newsgroup: sci.electronics
Document_id: 52798
From: mpaul@unl.edu (marxhausen paul)
Subject: How to kill AC inductive load spiking?

Is there a fast 'n dirty way to kill the line spiking that occurs when
an inductive load is turned on sometime other than at zero-crossing of
the AC cycle?  A capacitor kludged in somehow, etc?

I've got a microcontroller that is running a bunch of valves and pumps
in a big instrument washer, and almost everything is being switched with
zero-crossing solid state relays, so that stuff stays "quiet", AC-wise.
But there's one steam valve that gets turned on by a mechanical relay
in the water tank fill/thermostat system, and it's not under control
of my SSRs, and it does sometimes generate/radiate a spike that resets
one of my peripheral chips.  My software times out and tries again, but
I'd love to just tack in a magic spike-killing fix that would avoid having
to do some major rewiring/redesign.  A varistor would help but might not
be sufficient.  Ideas?

--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
Document_id: 52799
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Police radar....Just how does it work??

In article <1993Apr6.161107.2235@b30news.b30.ingr.com>, dtmedin@catbyte.b30.ingr.com (Dave Medin) writes:
|> In article <1993Apr2.182402.28700@walter.bellcore.com>, deaddio@ski.bellcore.com (Michael DeAddio) writes:
|> 
|> |> |> The 'beam' is split in two, with one beam aimed at the target car (sort of) and
|> |> |> the other at the ground.  The speeds of each are calulated for the final
|> |> |> number
|> |> 
|> |> Actually, this is true on the more expensive ones, but the cheaper ones
|> |> just read the speedometer.
|> 
|> I've never seen a speedometer-reading model. Are you sure? Who makes
|> them? Consider the difficulty of reading the speedo on various makes
|> of cars in use... I've seen single beam moving-mode and split beam
|> moving-mode.

Obviously the police officer reads the speedometer.
I cannot believe the nit-picking in this group.
There's 2 beams, there is not, is too, etc....

|> --------------------------------------------------------------------
|> [Dave Medin's 10 line sig deleted]


Newsgroup: sci.electronics
Document_id: 52800
From: nhowland@matt.ksu.ksu.edu (Neal Patrick Howland)
Subject: Re: Radar detector DETECTORS?

ragee@vdoe386.vak12ed.edu (Randy Agee) writes:

>It used to be that the only way the law could be enforced was for
>an officer to actually see the radar detector.  Not any more!  Many
>law enforcement agencies are now using radar detector detectors. 
>Right, a super sensitive receiver that is capable of picking up RF
>from the radar detector itself.  My first reaction was "no way!" 
>But, guess again, these little buggers really work and the police
>are writing citations right and left for people using radar
>detectors.  One news story quoted an officer as saying that he had
>found the radar detector in all of the cars he stopped except one,
>and he could never figure out where it was - but he knew it was
>there.  This tends to make one assume there are few false arrest.

From what I understand about radar dectectors all they are is a passive
device much like the radio in your car.  They work as an antenna picking
up that radar signals that the radar gun sends out.  Therefore there would
be no way of detecting a radar detector any more than there would be of
detecting whether some one had a radio in their car.  

Neal Howland
nhowland@matt.ksu.ksu.edu 


Newsgroup: sci.electronics
Document_id: 52801
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Where do U look??

In article <1993Apr2.170955.1749@cmkrnl.com>, jeh@cmkrnl.com writes:

|> I might add that collecting last year's data books (or even ones two years out
|> of date) is usually pretty cheap, and has benefits besides:  You usually DON'T
|> want to base a design on a brand-new chip.  There may be bugs; availability may
|> be limited; the data sheets may be missing critical information that will show
|> up in the ap notes in next year's data books.  Kinda like buying Version 1.0 of
|> a major new software package:  Sometimes you get lucky, but don't count on it.

There are two more reasons to save old databooks and then beyond two
years--obsoleted parts and better application notes and tutorials.

When a part is dropped from future production planning, such as the
National MM-series white noise generators, camera sync generators, etc.,
it will disappear from current databooks although it still may be produced
for a short time (or be available from stock somewhere). Now, if you
have some old plans calling for such a device, or you have a dead
gadget on your workbench and it has such a part in it, you'll know
the functions so you can troubleshoot and substitute as necessary.

The old GE thyristor data books contain real good tutorials on
SCR and triac applications that are not found elsewhere, for
example.

|> > In summary, read. READ! ****READ!!!**** That's how you'll know what to
|> > design in, which parts to use, and how to solve the intractable problem
|> > that your boss has presented you with. 
|> 
|> It helps to have a prodigous memory for details...

Here, here!...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 52804
From: corleyg@ul.ie
Subject: Microstrip help wanted

I need information on microstrip circuit design especially 
filter design for the 1-3GHz range. Can you recommend any
good books, journals, or microstrip circuit design software.
.
all help appreciated

Gerry Corley, ECE Department, Univesity of Limerick, Ireland.


Newsgroup: sci.electronics
Document_id: 52805
From: dpalmer@mcnc.org (W. Dev Palmer)
Subject: Re: Wanted: A to D hardware for a PC

In article <1993Apr6.053736.23113@doug.cae.wisc.edu> kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In <3889@ncr-mpd.FtCollinsCO.NCR.COM> Brad Wright writes:
>>
>>>	If you know much about PC's (IBM comp) you might try the joystick
>>>port.  Though I haven't tried this myself, I've been told that the port
>
>I believe that the "A-D converters" found on a joystick port are really
>timers that tick off how long it takes an R-C circuit (the R being your
>paddle) to charge up to something like 1/2 Vcc.  For games this works
>pretty well, but you certainly wouldn't want to try to take lab
>measurements off something as non-linear as that.

The best info I have seen so far is the article "Joystick Metrics:
Measuring physical properties through the PC's joystick port" by
Michael Covington in the May 1985 issue of PC Tech Journal.  It talks
about how to read all kinds of things (voltage, current, resistance) in
BASIC, and even includes code for a simple "oscilloscope" display.

It's possible to read the joystick port directly if you don't want to
use BASIC.  The detailed information for this is in the PC Technical
Reference under Options and Adapters.  You have to provide some
millisecond resolution timing functions, but that's a subject which has
appeared many times in articles from Dr. Dobb's, Circuit Cellar Ink,
etc.  Look for the public domain ztimer package on wuarchive.

Good Luck,

Dev Palmer
dpalmer@mcnc.org
MCNC Room 212
P.O. Box 12889
RTP, NC  27709-2889
(919) 248-1837
(919) 248-1455 FAX

Newsgroup: sci.electronics
Document_id: 52806
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Peltier Effect Heat Pumps


I was having a look through a couple of components catalogues when I
came across a range of Peltier Effect heat pumps intended for cooling
components.  For those who have not heard of this effect, you put a
current through one of these devices, and it pumps heat from one side
to the other.  Reverse the current and you reverse the effect.  I
think a temperature difference can give you an EMF as well.

Anyway, it struck me that you could make a nice cool/hot box for
picnics with one of these, a power regulator, a thermostat and a
couple of heat sinks.  The biggest device can shift 60W with an
efficiency of 80-90%, which ain't bad (although it would flatten my
car battery in about half an hour).

Unfortunately the catalogue didn't list anything more than the basic
specs as a heat pump.  I imagine that you would get a back-EMF as the
temperature gradient across the device increases.  If so, presumably
its power decreases as the back-EMF increases, until eventually we
have a steady state with no current being consumed (assuming no
leakage).  If so, then the final temperature difference between the
two sides could be set by the supply voltage and nothing more
(although that would be a lousy way to control it).

What I would like to know is:

1: Are the above guesses correct?

2: What is the open-circuit thermal resistance of a typical device?
   (I just want to be sure that my coolbox is not going to get warm
   too fast when I unplug it)

3: How does a Peltier Effect heat pump actually work?  It looks like
   magic!

4: Why don't they use these things in domestic fridges/freezers?


Thanks in advance,

Paul.

Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
Document_id: 52807
From: sciamanda@edinboro.edu
Subject: Re: Outdoor FM Antennas

In article <beerb.9.0@ccmail.dayton.saic.com>, beerb@ccmail.dayton.saic.com (Bradlee Beer) writes:
> I'm interested in buying or building an omnidirectional antenna for the 
> commercial FM band (88-108MHz).  The commonly sold ones are a folded dipole 
> bent in an "S" shape; and one with a pair of crossed dipoles.  I don't see 
> either of these designs as exhibiting any gain, and they probably aren't 
> truely omnidirectional.
> 
> 
> I'm intrigued by the discone antenna.  Does anyone have detailed information
> on how to design one for the FM band (with 75-ohm impedence)??  Is one
> commercially available??  Are there other designs that have GAIN??  
> 
> I already own a 10-element FM yagi.  It works great, but requires frequent 
> rotation for those distant stations.  
> 
> Brad Beer,  4414 Castle Gate Drive,  Beavercreek, OH  45432-1814

Brad,
   For an antenna, gain is synonymous with directionality.  The only way 
to get gain (>1) out of an antenna is to design in directionality. The 
"gain" of an antenna is defined as the signal increase (for a preferred 
direction) over the signal obtained by an isotropic antenna.

Bob Sciamanda
Edinboro Univ of PA

Newsgroup: sci.electronics
Document_id: 52808
From: row0@ns1.cc.lehigh.edu (RICHARD O. WHITE)
Subject: Re: Help with ultra-long timing


In article <1993Apr5.083324.48826@kuhub.cc.ukans.edu>, wellison@kuhub.cc.ukans.e
du writes:
>I have a project that was drooped in my lap that is somewhat a pain to design.
>What I am looking for is a stable ultra-long solid state timer. What they want
>to do is to place this thing on the Antartic ice shelf and measure the amount
>of snow fall over a period of six weeks. Every two weeks, they want to trip a
>selonoid to discharge different colored pellets by gas pressure out across the
>snow. Then by digging down into the snow, the snow fall amount can be measured
>as they come to the different color pellets.
>
>The problem is trying to build a timer that would stand the cold (-40 degrees)
>and a power source that wouldn't drain. I have looked at the XR-2204 timers and
>the standard NE556 dual timers, but thier temp specs won't go that low. Also,
>two weeks equates to 1,209,600 seconds per firing, which means one big timing
>cap ! I have found 2.2 farad (yes, Farad !) caps that have a working voltage of
>5 volts and are small in size. But again, the time of discharge at -40 or lower
>degrees isn't linear. I was thinking of using several timers chained together
>to fire the selonid at the end of the timing period, but that blasted cold and
>the drain on a battery over six weeks is the pain. One possibility would be to
>use solar panels, but this is during the six month twilight. Anyone have any
>good ideas ?
>
>Thanks in advance...
>
>-=-= Wes =-=-
>
just a suggestion:
take a motorola mc14536B set it up to give you a pulse once every sec or ten
secs with either a RC or xtal clock input. then feed to a MC14521B as clock
input and decode output for 1,209,600 sec output ,might have to add a few 'and'
gates or decoder chips to get output and reset pulse back to the'521 to restart
cycle... Trigger a oneshot from the decoded riseing edge ;the one shot then
goes to a mosfet to drive the mechanism to fire the pellet launcher..
these ckts require uAmps of current,between 5 - 15 volts, so a 12 volt
gel cell of a few Amphours would last the six weeks.
Then take the ckt board & battery wrap in 3" or 4" of foam or build a box
of out of the stuff...with plywood or metal exterior...
build a small heater out of 10-50 Watt resistors in series to keep the battery
and ckts warm.
2nd thought use 2 batteries one for heater one for timer and pellet trigger.

Insolate-insolate.......even though the chips state that the - AL
rated devices are good to -55 C.. The batteries have a considerable reduction
in capacity...oh make sure the area inside has minium air leakage..

hope this helps
RW     ( is this to long winded for the net??)(be gentle)...
-- 

Newsgroup: sci.electronics
Document_id: 52809
From: rg@futserv.austin.ibm.com (R.G. Keen)
Subject: Re: All Electronics Press and Peel PCB transfer

I think there is a huge difference in the materials and 
process for printer/toner PCB's. I get first time, everytime
results from a local HP Postscript, and hardly ever works from
copies of the same artwork. The printer results are so good
that I have quit even looking for PC board processes. If I had
to use the copier version, I would think I would look elsewhere.
The moral? Experiment and find what works. Toner transfer CAN
give excellent results. It, like any process, gives erratic 
results with variable inputs.

R.G.


Newsgroup: sci.electronics
Document_id: 52810
From: fsset@bach.lerc.nasa.gov (Scott Townsend)
Subject: Electric power line "balls"

I got a question from my dad which I really can't answer and I'd appreciate
some net.wisdom.

His question is about some 18-24" diameter balls which are attached to
electric power lines in his area.  He's seen up to a half dozen between
two poles.  Neither of us have any experience with electric power distribution.
My only guess was that they may be a capacitive device to equalize the
inductance of the grid, but why so many between two poles?.

Anyone know what they really are?  Is there a related FAQ for this?
Is there a better group to submit to?

We'd both appreciate some enlightenment.


-- 
Scott Townsend,  Sverdrup Technology Inc.  NASA Lewis Research Center Group
fsset@bach.lerc.nasa.gov

Newsgroup: sci.electronics
Document_id: 52811
From: jack@multimedia.cc.gatech.edu (Tom Rodriguez)
Subject: composite video - what are HD and VD?


	I've got an rgb Mistubishi monitor and on the back it has 5
BNC connectors labeled like this:

    composite
  HD          VD
  +           +        +       +       +
             sync     red    green    blue

	I've used it as a straight RGB monsitor but i can't figure out
how to use it for composite.  Could someone explain what these markings
mean?  Thanks for any help.

	tom
--
Tom Rodriguez  (jack@cc.gatech.edu)
Multimedia Computing Group - GVU Lab
Georgia Institute of Technology
Atlanta, Georgia 30332-0280

Newsgroup: sci.electronics
Document_id: 52812
From: gerg@netcom.com (Greg Andrews)
Subject: Re: Radar detector DETECTORS?

nhowland@matt.ksu.ksu.edu (Neal Patrick Howland) writes:
>
>From what I understand about radar dectectors all they are is a passive
>device much like the radio in your car.  They work as an antenna picking
>up that radar signals that the radar gun sends out.  Therefore there would
>be no way of detecting a radar detector any more than there would be of
>detecting whether some one had a radio in their car.  
>

Unfortunately, you're wrong on both counts.  The most common method of
implementing a tunable receiver is to have a local oscillator.  The
local oscillator's frequency can be radiated out of the receiver via
the antenna unless the circuit is designed and constructed with great
care.

For a reference on detecting radios, get the paperback book _Spy Catcher_.
The author discovered how to detect radio receivers from their local
oscillator emissions back in the *1950s* while he worked for British
Intelligence.

  -Greg
-- 
:::::::::::::::::::  Greg Andrews  gerg@netcom.com  :::::::::::::::::::
Fortune Cookie:  Radioactive cats have 18 half-lives.
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Newsgroup: sci.electronics
Document_id: 52813
From: behnke@FNALF.FNAL.GOV (M.L. 'Broomen' Behnke)
Subject: Re: Peltier Effect Heat Pumps

In article <2745@snap>, paj@uk.co.gec-mrc (Paul Johnson) writes:
>
>I was having a look through a couple of components catalogues when I
>came across a range of Peltier Effect heat pumps intended for cooling
>components.  For those who have not heard of this effect, you put a
>current through one of these devices, and it pumps heat from one side
>to the other.  Reverse the current and you reverse the effect.  I
>think a temperature difference can give you an EMF as well.
>
>Anyway, it struck me that you could make a nice cool/hot box for
>picnics with one of these, a power regulator, a thermostat and a
>couple of heat sinks.  The biggest device can shift 60W with an
>efficiency of 80-90%, which ain't bad (although it would flatten my
>car battery in about half an hour).
>
 So-Called Cool-Hot boxes have been advetised for several years.  I recall
Damark advertising them in a recent catalog.  Problem with the units is they do
a sh***y job of keeping food cold/warm.  The peliter devices used just don't
seem to have enough punch to keep up.  If you want something hot, you need to
heat it up before you put it in the box, and end up hours later with food thats
only moderately warm.  Same goes for cold items.

>Unfortunately the catalogue didn't list anything more than the basic
>specs as a heat pump.  I imagine that you would get a back-EMF as the
>temperature gradient across the device increases.  If so, presumably
>its power decreases as the back-EMF increases, until eventually we
>have a steady state with no current being consumed (assuming no
>leakage).  If so, then the final temperature difference between the
>two sides could be set by the supply voltage and nothing more
>(although that would be a lousy way to control it).
>
>What I would like to know is:
>
>1: Are the above guesses correct?
>
>2: What is the open-circuit thermal resistance of a typical device?
>   (I just want to be sure that my coolbox is not going to get warm
>   too fast when I unplug it)

 You'de probably be better off getting a good Coleman(tm) cooler and stocking
up on "blue ice" blocks.

>
>3: How does a Peltier Effect heat pump actually work?  It looks like
>   magic!
>
>4: Why don't they use these things in domestic fridges/freezers?
>
 Same as above.  Not enough "punch" in them to keep/get things cold/hot.
>
>Thanks in advance,
>
>Paul.
>
>Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
>--------------------------------------------+----------------------------------
>These ideas and others like them can be had | GEC-Marconi Research is not
>for $0.02 each from any reputable idealist. | responsible for my opinions
Mike Behnke             | Senior Tech/Advisor | Quid est illuidin aqua??
Fermi Nat Accel Lab     | Equipment Suuport   |
Batavia, Il.            | Computing Div       | PISTRIX!!  PISTRIX!!
BEHNKE@FNALF.FNAL.GOV   |                     |

My opinions are my own, not of the lab. So, if you don't like them, call

1-800-UWH-INER

Newsgroup: sci.electronics
Document_id: 52814
From: sidhu@ee.ualberta.ca (Kenneth Sidhu)
Subject: Dimming Incand. Lamps


 
  
  
What's the latest and greatest way to dim incandescent lamps ?

March '93 Circuit Cellar has part one of an article about
dimming 120VAC lamps, but it seems to lead into phase-
control as the best method for controlling brightness.
  I've always hated phase-control for the RFI, buzzing
filaments and non-linear adjustment range. I had
heard that you can modulate the AC line on a cycle by
cycle basis to get better results. To cut the lamp's
power to 50% you would givemsay 20 cycles of AC, then
nothing for another 20 cycles. I wonder if anyone has
tried this or knows what the pro stuff is using. Any
advice is appreciated!

Ken


email: sidhu@bode.ee.ualberta.ca

Newsgroup: sci.electronics
Document_id: 52815
From: gtalatin@vartivar.ucs.indiana.edu  (Gerard V. Talatinian)
Subject: Low cost oscilloscopes?

I am looking at buying a low cost (< $500) scope for general purpose use.
Any recommendations? Is this info in a faq somewhere?
Any pointers appreciated.
Thanks,
  -Gerard.

******************************************************************
* Gerard Talatinian                 |                            *
* Network Systems                   |   gtalatin@ucs.indiana.edu *
* University Computing Services     |   FAX:   (812) 855-8299    *
* Indiana University                |   Voice: (812) 855-0962    *
******************************************************************

Newsgroup: sci.electronics
Document_id: 52816
From: ritley@uimrl7.mrl.uiuc.edu ()
Subject: SEEKING THERMOCOUPLE AMPLIFIER CIRCUIT



I would like to be able to amplify a voltage signal which is
output from a thermocouple, preferably by a factor of
100 or 1000 ---- so that the resulting voltage can be fed
more easily into a personal-computer-based ADC data
acquisition card.

Might anyone be able to point me to references to such
circuits?  I have seen simple amplifier circuits before, but
I am not sure how well they work in practice.

In this case, I'd like something which will amplify sufficiently
"nicely" to be used for thermocouples (say, a few degrees
accuracy or better).

Any pointers would be greatly appreciated!

Newsgroup: sci.electronics
Document_id: 52817
From: bailey@vader.egr.uri.edu (Scott Bailey)
Subject: Re: Jacob's Ladder

Hi all,
 I've been following this thread about jacob's ladder for a few weeks and I
happened to come across one of the best project books that I've seen in a 
while.  The book "Gadgeteer's Goldmine" by Gordon McComb offers over 55 
excellent low cost projects including: Jacob's Ladder, tesla coils, plasma 
spheres, a Van de Graaff generator, robots, an IR scope, and several laser 
projects.  The instructions come with complete part lists, warnings and 
diagrams.  For those of you who are interested in building any of the above 
listed projects, you should seriously consider getting this book.  The 
paperback version is only $19.95 too.

For those who want more information:
Title: Gadgeteer's Goldmine!  55 Space-Age Projects
Auth:  Gordon McComb
Pub:   TAB Books
CW:    1990
ISBN:  0-8306-8360-7
	0-8306-3360-X (paperback)
 Price: $19.95 (paperback)

 -Scott

/-----------------------------------------------------------------------------\
| Scott A. Bailey            | #include "std_disclaimer.h"                    |
| ECL Operator               |------------------------------------------------|
| Computer Engineering       | I'm just a knight who chases the moon...       |
| University of Rhode Island | Haven't caught it yet,but I haven't let that   |
| bailey@vader.egr.uri.edu   | keep me from still trying each day and night   |
| bailey@ecl1.uri.edu        |    --(----------           ----------)--       |
\-----------------------------------------------------------------------------/

Newsgroup: sci.electronics
Document_id: 52818
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: What is Zero dB????

In article <1993Apr6.092913.18724@sei.cmu.edu> rsd@sei.cmu.edu (Richard S D'Ippolito) writes:
>
>In article <1pkveuINNduk@gap.caltech.edu>, Joseph Chiu writes:
>
>> The Ohmite company was the first to characterize resistances by numbers, thus
>> our use of the Ohms...
>
>
>Yeah, right.  And the company was started by George Simon Ohmite.

That's completely inaccurate.  The ohm was an original standard made equal
to a the resistance of a standardized electric stove heating element.  That's
where the song "Ohm on the Range" came from, of course.
--scott

Newsgroup: sci.electronics
Document_id: 52819
From: zstewart@nyx.cs.du.edu (Zhahai Stewart)
Subject: Re: Police radar....Just how does it work??

>The father of a friend of mine is a police officer in West Virginia.  Not  
>only is his word as a skilled observer good in court, but his skill as an  
>observer has been tested to be more accurate than the radar gun in some  
>cases . . ..  No foolin!  He can guess a car's speed to within 2-3mph just  
>by watching it blow by - whether he's standing still or moving too!  (Yes,  

1) How was this testing done, and how many times?  (Calibrated speedometer?)

2) It's not the "some cases" that worry me, it's the "other cases" :-)

(eg: suboptimal viewing conditions; even the best subjective viewer can only
partial compensate for certain distortions and optical illusions).


Newsgroup: sci.electronics
Document_id: 52820
From: gleasokr@rintintin.Colorado.EDU (Kris Gleason)
Subject: Re: Electric power line "balls"

fsset@bach.lerc.nasa.gov (Scott Townsend) writes:

>I got a question from my dad which I really can't answer and I'd appreciate
>some net.wisdom.

>His question is about some 18-24" diameter balls which are attached to
>electric power lines in his area.  He's seen up to a half dozen between
>two poles.  Neither of us have any experience with electric power distribution.
>My only guess was that they may be a capacitive device to equalize the
>inductance of the grid, but why so many between two poles?.

>Anyone know what they really are?  Is there a related FAQ for this?
>Is there a better group to submit to?

>We'd both appreciate some enlightenment.

I think those are to make the lines more visible to airplanes and
helicopters... cheaper than blinking red lights.

'course I could be wrong.

Kris


Newsgroup: sci.electronics
Document_id: 52821
From: depolo@eniac.seas.upenn.edu (Jeff Depolo)
Subject: Need manual for HP 1740 scope


I have a HP 1740 scope that (I think) has a problem in the HV section.
Symptom: started turning on and off on its own, making intermittant
bright flashes on the CRT, and then finally, passed away.  If you
have a manual (or any suggestions), please send me mail.  Will gladly
pay reproduction/shipping costs plus a little $ for your efforts for
the manual.  Thanks in advance.

								--- Jeff
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 Jeff DePolo  WN3A              Twisted Pair: (215) 337-7383H  387-3059W  
 depolo@eniac.seas.upenn.edu    RF: 443.800+ MHz    442.700+ MHz    24.150 GHz
 University of Pennsylvania     

Newsgroup: sci.electronics
Document_id: 52822
From: mneideng@thidwick.acs.calpoly.edu (Mark Neidengard)
Subject: Re: What is Zero dB????

>>: The Ohmite company was the first to characterize resistances by numbers, thus
>: our use of the Ohms...
>
>I don't know about this one, but it doesn't sound right.

DAMN RIGHT it doesn't!  Ohm's come from the greek letter omega, which
is used for resistance/impedance.

Of course, the original poster MAY have been being facetious (let's hope
so).

Mark Neidengard
mneideng@cosmos.acs.calpoly.edu

Newsgroup: sci.electronics
Document_id: 52823
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Subject: Re: few video questions

In article <7480224@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>situation sometimes called "block" sync).  You can generate such a combined
>(or "composite") sync in two simple ways - OR the H. and V. syncs together,
>which gives you the non-serrated "block" sync, or EXOR them, which makes
>serrations.  (Try it!)  Actually, the EXOR doesn't really do kosher serrated
>sync, since it puts the rising (and falling, for that matter) edge of the H. 
>sync pulse off by a pulse width.  But that usually makes no difference.

Sometimes.  It depends on your monitor and your timing.  If you don't
have enough vertical front porch and you use XOR composite sync you can
get even/odd tearing at the top of the screen, which is very sensitive
to the HHOLD control.  It looks like what you would expect if you
scanned the even fields (say) onto a sheet of mylar and had pinched the
upper left corner with your fingers and started to tear it off the tube. 
With proper composite sync (equalizing pulses) the interlace is rock
solid. 

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			One Design to rule them all; one Design to find them.
			One Design to bring them all and in the darkness bind
			them.  In the land of Mediocrity where the PC's lie.

Newsgroup: sci.electronics
Document_id: 52824
From: dzenc@hal.gnu.ai.mit.edu (Dan Zenchelsky)
Subject: VIdeotext/teletext descrambler

Hi,

I am looking for a PC card which does european videotext/teletext
descrambling (PAL). Does anyone in the US sell such a card? I once
saw an article about a card with the same functionallity in a
european Elektor magazine, but I wasn't able to track it down.

Thanx in advance,
Dan

Newsgroup: sci.electronics
Document_id: 52825
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Electric power line "balls"

In article <1993Apr6.203237.20841@eagle.lerc.nasa.gov>,
fsset@bach.lerc.nasa.gov (Scott Townsend) wrote:
> 
> I got a question from my dad which I really can't answer and I'd appreciate
> some net.wisdom.
> 
> His question is about some 18-24" diameter balls which are attached to
> electric power lines in his area.  He's seen up to a half dozen between
> two poles.  Neither of us have any experience with electric power distribution.
> My only guess was that they may be a capacitive device to equalize the
> inductance of the grid, but why so many between two poles?.
I'll bet there's a runway nearby.

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
Document_id: 52826
From: smithr@teecs.UUCP (Robert Smith)
Subject: Re: Conductive Plastic, what happened?

If you're thinking of reactive polymers they're making ESD safe
contauiners out of it. As far as being conductive goes anything with
a resistance less than 10 to the fouthrth power ohms per cubic measure
is classed as conductive per MIL-STD-1686 for ESD protection. My $0.02
($0.016 US).

Bob.

Newsgroup: sci.electronics
Document_id: 52827
From: young_dick@macmail2.rtsg.mot.com (Dick Young)
Subject: ATTN: H. Wheaton, UCal Davis

I tried to E-mail you, but the message bounced.

Motorola has a University Support Program through which (I've been told) folks
at schools can get sample quantities of parts.  If you'd like to try this 
route, e-mail me for the address/phone #...I don't wish to post it for all the
world to see.

Dick Young
Motorola, Inc.
(Who doesn't have a thing to do with my opinions: They're my own fault.)


Newsgroup: sci.electronics
Document_id: 52828
From: advax@reg.triumf.ca (A.Daviel)
Subject: Re: Radar detector DETECTORS?

In article <1pslckINNmn0@matt.ksu.ksu.edu>, nhowland@matt.ksu.ksu.edu (Neal Patrick Howland) writes...
> 
>From what I understand about radar dectectors all they are is a passive
>device much like the radio in your car.  They work as an antenna picking
>up that radar signals that the radar gun sends out.  Therefore there would
>be no way of detecting a radar detector any more than there would be of
>detecting whether some one had a radio in their car.  
> 
From my rather rusty knowledge of radio, most radio receivers use a superhet 
circuit, so that the incoming signal is mixed with a local oscillator, giving 
a fixed intermediate frequency (IF) that is more easily amplified. The
detector detectors work by picking up IF re-radiated from your radar 
detector. In Britain, where one has/used to pay for a TV licence, there 
are/were TV detector vans prowling the streets, looking for people who hadn't 
paid their licence fee. They had a couple of long solenoid antennae on the
roof, and I believe could triangulate an operating TV from the IF. 

I wonder how much of the IF is radiated back from the detector antenna, and 
how much from the rest of the module. It might be worth putting the detector 
in a proper RF shielded enclosure.

--
 Andrew Daviel, Vancouver, Canada <advax@triumf.ca>
  finger advax@reg.triumf.ca for PGP key

Newsgroup: sci.electronics
Document_id: 52829
From: mark@wdc.sps.mot.com (Mark Shaw)
Subject: Re: Rumors

In article <1993Apr2.174851.22659@cs.unca.edu>, kepley@photon.phys.unca.edu (Brad Kepley) writes:
|> I just heard an unbelievable rumor that Motorola has decided to drop their
|> integrated circuit manufacture business.  Apparently a Digikey rep called 
|> one of our production coordinators, for out information so that we could
|> make plans to deal with this, that Moto was getting out.  Anybody else
|> get a call about this?
|> 
|> Too much for me.  It's about like Intel announcing they were getting out
|> of the IC business.


This rumor didn't happen to appear on April 1st?

If this DigiKey rep was serious, I think I will buy my parts elsewhere.
If that is the way they do business, you cannot trust them.

Mark

Newsgroup: sci.electronics
Document_id: 52830
From: Joseph N Hosteny <jh8e+@andrew.cmu.edu>
Subject: Re: Electric power line "balls"


    Do you know if there is an airport nearby? They may just be markers
to tell pilots of small planes that there are power lines nearby.

/Joe

Newsgroup: sci.electronics
Document_id: 52831
From: ubsiler@msuvx1.memst.edu
Subject: Home-made IR remote extender

Here's a question for all you electrical engineers out there:

  I bought an 'Infrared detector module' at Radio Shack for $3.95 - it is a 
little gizmo that senses infrared remotes and produces an output signal. Then
I hooked the output through a transistor to an infrared LED. The circuit works
like a minature remote control extender in my car - All remote commands are
relayed to the CD player hidden in the glove compartment. It works fine with
my Denon CD player, but when I tried to build the same circuit for a friend's
VCR, it didn't work.
  The circuit appears to work for other remotes (you can see infrared with a
Sony CCD camcorder) but coincidentally it only seems to work for my CD
player...

	Any advice would be appreciated....
        Brian

---
UBSILER @ MSUVX1.MEMST.EDU


Newsgroup: sci.electronics
Document_id: 53128
From: et@teal.csn.org (Eric H. Taylor)
Subject: Holes: practical questions, was - Philosophical Question

In article <12426@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>[...]
>I agree.  I come at this from nuclear physics, where one often discusses 
>particle-hole excitations and certain reactions have the effect of 
>applying an annihilation operator and creating a hole, and it is a 
>subtle question.  The longer one works with them, the more real they 
>become.  There are also quasi-particles, which raise the same sort 
>of question about how "real" the entity is.  The phenomenon is most 
>certainly a real one. 

OK, I've asked this before, and with a new thread on these lines, I
ask this again:

1: If a large hole current is run thru a resistor, will there be
   I^2 * R cooling instead of heating?

2: Can anyone design an amplifier that preferentially amplifies
   hole currents over normal electron currents?

3: what semiconductor materials have the highest ratio of
   hole mobility to electron mobility? (please quote actual
   test samples rather than estimates based on theory. Also,
   don't be limited to semiconductors: consider also insulators,
   resistors, dielectrics, piezo-electrics, conductors,
   magnets (metal, ceramic), magnetostrictives, etc).

NOTES:

   to summarize, this thread has so far stated that the only area
   where holes are not detectable is the vacuum. That is, hole
   particles only exist in the presence of matter.
   Previous threads have stated that holes only exist in certain
   semi-conductors. The question that naturally arises is if
   the hole currents inside a semi-conductor vanish at the point
   where the semiconductor is joined to a conductor (say, copper).
   I don't want a theoretical discussion here about whether
   holes could exist inside metal conductors, rather I ask for
   an experimental discussion on how to amplify and detect such
   currents *if* they exist.
   Also note that I have cross-posted this to sci.electronics
   since this is now becoming an electronic discussion.

Thanx,
Eric.

----
 ET   "A Force of Nature"
----

Newsgroup: sci.electronics
Document_id: 53502
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Need tone decoder circuit

In article <5170286@hplsla.hp.com> tomb@hplsla.hp.com (Tom Bruhns) writes:
>>Does anybody out there have a circuit that will decode a 1000Hz tone?
>
>Use a NE567 tone decoder PLL chip...

My impression -- it's not an area I've played with much -- is that the
much-beloved NE567 is basically obsolete.  If you want to detect a 1kHz
tone, set a switched-capacitor filter chip to that frequency, feed your
input to it, and see if anything comes out the other end.  The NE567 was
what you used when good clean bandpass filters were hard to do; nowadays
they're easy, and the results are better.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53503
From: heuvel@neptune.iex.com (Ted Van Den Heuvel)
Subject: Motorola MC143150 and MC143120 


Does anyone out there know of any products using Motorola's Neuron(r) chips MC143150 or MC143120. If so, what are they and are they utilizing Standard Network Variable Types (SNVT)?
_________________________________________________________________________________

Ted Van Den Heuvel   heuvel@neptune.iex.com
KX5P

Newsgroup: sci.electronics
Document_id: 53504
From: rich1@netcom.com (Richard Soennichsen)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

The Bmw speedo is triggered by a reed switch\magnet assembly in the differential. I would think that this signal would be easy to reproduce.

Newsgroup: sci.electronics
Document_id: 53505
From: obrien@hri.com (Jim Obrien)
Subject: IBM-PC XT switch settings

I just got an IBM-PC XT with no documents. Its a true
IBM, and I was wondering if anyone had the definitions
of the 2 8 position dip switches? 

- thankx Jim



Newsgroup: sci.electronics
Document_id: 53506
From: bell@hops.larc.nasa.gov (John Bell)
Subject: Re: Adcom cheap products?

In article <mdonahue.15x9@amiganet.chi.il.us> mdonahue@amiganet.chi.il.us (Mike Donahue) writes:
>
>As for Adcoms Mobil, They are going with amps that canb use Balanced Inputs, a
>VERY nice toy, but I'm afraid its goig to push their amps beyound resonable
>price ranges.  especialy because taking advantage of those balanced inputs
>requires a $120+ RCA to Balanced adapter...

Umm, when I was doing sound reinforcement for a living, I used to get direct boxes (which convert
unbalanced 1/4" jacks to balanced XLRs) for about $25 each, or a little more for higher
quality. You'll need two for a stereo signal, of course, and a little adapter thingy from 
Radio Sh#$&^t to convert from RCA to 1/4". Total cost should be around $50. You can also buy
transformers for quite a bit less and wire them yourself. Total cost there should be under $30.
You can get all this stuff from any pro music shop that sells sound reinforcement gear.
The benefit? NO noise that you can hear will be generated in the cables going to the component
with the balanced inputs, even when you run them in bad places, like next to power lines.

-----
John Bell
NASA Langley Research Center
bell@hops.larc.nasa.gov


Newsgroup: sci.electronics
Document_id: 53507
From: moffatt@bnr.ca (John Thomson)
Subject: Re: Telephone on hook/off hok ok circuit 

Tony Kidson (tony@morgan.demon.co.uk) wrote:
: In article <oHZs2B2w164w@k5qwb.lonestar.org> lrk@k5qwb.lonestar.org writes:
: 
: >mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
: >
: >> In article <1ptolq$p7e@werple.apana.org.au> petert@zikzak.apana.org.au (Peter
: >> >
: >> >Just a thought of mine here:
: >> >Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 1
: >> >How about an LED in series with a zener say around 30V.
: >> >On-hook = LED on
: >> >Off-hook = LED off.
: >> >Would this work? If anyone tries/tried it, please let me know.
: >>
: >> Aye, there's the rub -- if you draw enough current to light an LED, the
: >> equipment at the phone company will think you've gone off hook.
: >> In the on-hook state you're not supposed to draw current.
: >
: >Which means you should just use your Digital VoltMeter. You can use an
: >old VOM but the phone company equipment can detect that and might think
: >there's something wrong with the cable.
: >
: 
: Look Guys, what's the problem here?  If you want a light that goes on when 
: the 'phone is *Off* hook, all you need it to run it in *series* with the 
: line, as I mentioned in my previous post.  If you want a light that goes on 
: when the 'phone is *on* hook, all you need is a voltage threshold detector.

If you're going to do the series Diode thing (which is the easiest), just
make sure that the LED can take the current (I can't recall it off-hand, but
it's something like 100mA or more?)

Greggo.

Greg Moffatt  moffatt@bnr.ca
Bell-Northern Resarch Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
Document_id: 53508
From: dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz)
Subject: Dumb Question: Function Generator


	I have a new scope and I thought I'd save a few bucks by
buying one with a function generator built in. After having it awhile
I noticed two things about the function generator. For one, there
seems to be a bias even when the 'pull-offset' is pushed in. That is,
I have to pull that know and adjust it to get a signal sans some
random 50mV bias.
	The other _really_ annoying thing is that the damn output
won't go below about 1V p-p. I am a student ( you may have guessed
from my previous posts ), and I often have to measure the input
impedances of various circuits I build.Many of the circuits have
maximum input signals of way less than 500mV amplitude and most have
input impedances in the 10's of Kohm range. The thing is, in order to
use my function generator I have to divide the voltage to some thing
reasonable. Then, of course, to measurethe input impedance of my
circuit I am going to have to throw in another resistor in series.
With the 50ohm output of the generator I could just ignore it, but now
with this little divider there I have to figure that in. It's kind of
a pain in  the ass.
	Is there any way I could make myself a little box that could
solve this little problem. The box would tkae the function generator
input, lower the voltage and give an output impedance that is some
low, unchanging number. I would want to lower the voltage by a factor
of one hundred or so. I could just build a little buffer amp, but I'd
like to have this box not be active.
	Any quick ideas. The scope's not broken. For other reasons I
had sent it to the shop to get repaired and they replaced it. The
function generator was the same way on that one, too.

			please help as I am feeling very stupid 
			today,

						dave 
						dgj2y@virginia.edu


Newsgroup: sci.electronics
Document_id: 53509
From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
Subject: Can I use a CD4052 analog multiplexer for digital signals?

As the subject says - Can I use a 4052 for digital signals?  I don't see
why it couldn't handle digital signals, but I could be wrong.  Anyone have
any advice?  Thanks.


 _I_______________________________________________________________________I_
(_@_)                                                                   (_@_)
|   |   Raymond Yeung               Internet: Nimbus@uiuc.edu           |   |
|   |                                         rky57514@uxa.cso.uiuc.edu |   |
|   |   EE student at the                                               |   |
|   |   University of Illinois    CompuServe: 70700,1011                |   |
|   |   at Urbana-Champaign                                             |   |
(___)-------------------------------------------------------------------(___)
  I                                                                       I

Newsgroup: sci.electronics
Document_id: 53510
From: sciamanda@edinboro.edu
Subject: Re: Emergency Vehicle Sensors?  traffic-light-phreaks?

In article <LINNIG.93Apr7154239@m2000.dseg.ti.com>, linnig@m2000.dseg.ti.com (Mike Linnig) writes:
> Folks,
> 
> Here in the Dallas area I have noticed that it is quite common to see an odd
> "sensor" on top of traffic lights.  These have been here for at least six
> years.  I've often wondered what they are.
> . . . 
> Mike Linnig, Texas Instruments Inc. | 97.43% of all statistics are made |
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Here in Erie, PA there is a system in the inner city called Rado-Lite (a 
trade name) which allows police and ambulance vehicles to gain right of 
way by controlling traffic lights through RADIO signals.  The receivers 
look much like what you describe, but they include a UHF whip antenna (less
than a foot tall) and a light which flashes on and off to let traffic know that 
an emergency vehicle has taken control and is approaching.  Local folklore 
says this system was invented here; I don't know if this company has any 
other installations.  It has been in operation for at least 30 years, going 
only by my memory.

Bob Sciamanda
Edinboro Univ of PA

Newsgroup: sci.electronics
Document_id: 53511
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: FAQ - corrections


	Greetings. I received a reply stating that unless someone else
	confirms that the following company is operating, I should
	remove it from my lst:

>PCB Prototypes of Sandy, UT
>Ronald Baker
>8195 South 2660 East
>Sandy, UT  84093
>Tel: [read below]
	
	This is from the COMM_PCB.FAQ (commercial PCB makers).

	Also, I don't have time to get the FAQ onto the sci.answers
	because of what I like to refer to is "red tape" - after the
	finals, I'll see what I can do... in the mean-time, anyone know
	of an FTP site that wouldn't mind a 250K file? :-)

	And last, I have some new entries for the SIMUSOFT list (mostly
	commercial/institutional stuff) but was wondering: should I keep
	the restrictions on the price of the software to be considered ->
	under $600 or should I include all those in 4 digit prices also?

	Take care.
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
Document_id: 53512
From: cab@col.hp.com (Chris Best)
Subject: Re: Illusion

> This is not a new idea.  At least 10 years ago I got this little gadget with
> a keyboard on the back and 8 LED's in a vertical row on the front.  It has a
> long handle and when you wave it in the air it "writes" the message you typed
> on the keyboard in the air. 

----------

This is not news.  In fact it's where I got the idea from, since it was
such a neat item.  Mattell made it, I believe, modeled after a "space 
saber" or "light sword" or something likewise theme-y.  My addition was 
using a motor for continuous display, and polar effects in addition to 
character graphics.  I should have protected it when I had the chance.  
No one to kick but myself...

Ten years ago is about right, since I built mine in '84 or '85.

Newsgroup: sci.electronics
Document_id: 53513
From: cab@col.hp.com (Chris Best)
Subject: Re: Need help with car stereo....

Just a shot here, but ya never know:

I once bought a (REAL) cheap equalizer / power amp for my car tape player 
at one of those motel-room truckload sales, and it sounded great.  For a 
while, that is.  Then one channel quit entirely.  I opened it up, and the 
amplifier chip for the bad channel had simply melted some of its solder 
joints attaching it to the PCB.  I soldered them back and it worked fine.  
I just had to keep the volume a bit lower than I did before.  Probably 
lousy heat sinking.

You said "a nice Alpine" which I'm sure is a few orders of mag higher
in quality than the P.O.S. I had.  But the point is - look inside before
you scrap it, since you OCCASIONALLY find something you can repair.
Maybe even the same thing I found.

Good luck!

Newsgroup: sci.electronics
Document_id: 53514
From: cab@col.hp.com (Chris Best)
Subject: Re: Uninterruptible Power Supply

I'm no expert at UPS's, but you said something that made it sound like
you didn't realize something.  On a typical UPS (well, on ours, anyway),
there is NO switchover from AC to DC.  All the protected equipment is
ALWAYS running from the batteries (via an inverter), with the usual 
condition of also having them on charge.  If the power fails, big deal - 
the computers never see it (until the batteries start to droop, but 
there's something like 60 car-sized batteries in that cabinet, so it 
takes a while).

If you were gonna run the guts on straight DC instead of an inverter,
why not do it all the time?  Then there'd be no switchover to screw
things up, and no having to sense the failure fast.  Just keep the DC
on charge when the power is on, and it'll be there in zero time when
you "need" it.

Just some ideas.  Can't guarantee what'll work or not, but hope at least
SOME of this helped.

Newsgroup: sci.electronics
Document_id: 53515
From: prasad@vtaix.cc.vt.edu (Prasad Ramakrishna)
Subject: Exploding TV!

I had a GE Emerson 13" color TV for about 3 years and one fine day,
while we were watching something (I doubt if the program was the cause),
we heard a mild explosion.   Our screen went blank but there was sound,
so we thought, 'oh we have special effects on the program'.  But soon
the sound stopped and smoke started to appear at the back of the TV.
The brilliant EEs we are, we unplugged the TV and called customer service
only to be thrown around by please hold, I will transfer u to blah blah..
  Finally we abandoned the idea of trying to fix the TV and got a new one
(we wanted a bigger one too!).
 After all the story, what I wanted to know is: Is my problem an isolated
incident or a common one? (I recall reading about Russian TVs exploding, but
not here, in the US). Why would the picture tube explode or even smoke?
 I still have the left over TV set, I might dig into it this summer. Any
idea where I can get parts for these things? (probably will cost more than TV).

W/my 0.02
Prasad
prasadr@vtvm1.cc.vt.edu


Newsgroup: sci.electronics
Document_id: 53516
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates
From: sldf3@sol.ee.usu.edu (Weston R Beal)

In article <C5Hs5J.AG7@bcstec.ca.boeing.com>, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:

|> It seems reasonable to me that a microwave transmitter-receiver setup could 
|> do the job. For example, say you want to map an acre lot, it'd be convenient
|> to place MW transmitters around the lot's periphery (either 2 or 3) and then
|> carry a hand-held recorder and walk to a point on the lot, press a button and
|> the coords of the recorder's location is stored as digital data.
|> 
|> What's the chance of this working? Any systems like this already exist?
|> What kind of accuracy could you expect? What would something like this
|> cost to prototype? Is there a better alternative than microwaves?

Of course you could develope this system, but there is already a system called Global
Positioning Satellites.  It gives three dimensional coordinates anywhere on earth. 
Many surveyors use this system with a differential receiver/transmitter to get
coordinates within centimeters.  Basic receivers with resolution of a few meters (on
a good day) are available from many sources.


-- 
WMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMW

  \_      \_  \_\_\_    \_\_\_               Weston R Beal
   \_      \_  \_    \_  \_    \_         sldf3@sol.ee.usu.edu
    \_  \_  \_  \_\_\_    \_\_\_            sldf3@cc.usu.edu
     \_\_  \_\_  \_  \_    \_    \_       Electrical Engineer
      \_      \_  \_    \_  \_\_\_       Utah State University

  "That's the wonderful thing about crayons; they can take you to
   more places than a starship can."    - Guinon



Newsgroup: sci.electronics
Document_id: 53517
From: carlos@math.lsa.umich.edu (Carlos Montenegro)
Subject: Low voltage lighting and X10 questions.

1. Can low Voltage lights be controlled with an X10  module by putting it 
before the transformer? It seems to work, even the dimmer works. Not very 
reliable. Will it damage the module? Can it be done reliably?

2. I put a motion switch (Heath) to a low voltage light, it worked but now it is
broken, too much current? How can I get arround that? 
  
3. How can I increase the intensity of a light using the X10 PC computer
interface without having it go 100% on first and then down. I am doing
my own programing, not the X10 program.

Thanks   C. Montenegro 

Newsgroup: sci.electronics
Document_id: 53518
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Dumb Question: Function Generator

In article <C5J845.3B8@murdoch.acc.Virginia.EDU> dgj2y@kelvin.seas.Virginia.EDU (David Glen Jacobowitz) writes:
>
>	I have a new scope and I thought I'd save a few bucks by
>buying one with a function generator built in.

Hmm... now where was that ad for the combination radio/hand cranked
generator/flashlight/siren I saw? :-)

[function generator has a 50mV offset, and the amplitude's too high]

>	Is there any way I could make myself a little box that could
>solve this little problem. The box would tkae the function generator
>input, lower the voltage and give an output impedance that is some
>low, unchanging number. I would want to lower the voltage by a factor
>of one hundred or so. I could just build a little buffer amp, but I'd
>like to have this box not be active.

Sure, you've already got the right idea.

Ignoring the 50 ohm internal resistance of the generator for a second, just
run it into, say, a voltage divider made of 990 ohms in series with 10
ohms.  This new circuit is the Thevenin equivalent of one that puts out
1/100 of the original voltage, and has an output impedence of negligibly
less than 10 ohms.  You may want to monkey with the values a little
depending on whether you care more about the _exact_ dividing ratio or
the availability of parts.

Hows that sound?

					---Joel Kolstad

P.S. -- This is why those 1000:1 high voltage probes for multimeters can be
accurate but still cheap.  They have something like 100 megs in series with
100k, which doesn't load the (often high impedence) source much, as well as
keeping the (probably 10 meg impedance) multimeter happy.

Newsgroup: sci.electronics
Document_id: 53519
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: what to do with old 256k SIMMs?

In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
|> >	I was wondering if people had any good uses for old
|> >256k SIMMs.  I have a bunch of them for the Apple Mac
|> >and I know lots of other people do to.  I have tried to
|> >sell them but have gotten NO interest.

We use them as Christmas tree decorations, the cat doesn't eat these.

-- 

	...Wex

Newsgroup: sci.electronics
Document_id: 53520
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: A question about 120VAC outlet wiring.. (the truth)

I suggest that misc.consumer.house is a better forum for this, several
electricians, a huge FAQ that adresses ALL the issues raised here.

-- 

	...Wex

Newsgroup: sci.electronics
Document_id: 53521
From: lancer@oconnor.WPI.EDU (Stephe Lewis Foskett)
Subject: How do DI boxes work?


I'm doing sound for a couple of bands around here and we need Direct
Input boxes for the keyboards.  These are the little boxes that take a
line level out of the keyboard and transform it into low-Z for the run
to the mixer.  Sadly they cost like $50 (or more) each and I'm going
to need like 5 or 10 of them!  I looked inside one (belonging to
another band) and it looks like just a transformer.  Does anyone have
any plans for building them?  Perhaps in Anderton's "Electronic
Projects for Musicians" book (which I am having a hell of a time
tracking down...)?

Thanks a lot!

.s.

PS: Post or email.  I read this group...
--
- lancer@wpi.wpi.edu -                    - 0{{  MoDiMiDoFrSaSo: -
-   Mein Kopf ist ein Labyrinth, mein Leben ist ein Minenfeld    -

Newsgroup: sci.electronics
Document_id: 53522
From: msf@skaro.as.arizona.edu (Michael Fulbright)
Subject: Re: Analog switches/Balanced Demodulators

caadams@atlas.cs.upei.ca (Kenny Adams) writes:

>hi,
>	instead of using a +15vdc supply for the 4066 try using a +7 and -7
>volt supply.  i have some commercial audio equipment that uses this approach
>for ground referenced audio.  they use the -7 volt supply as the logic
>ground.

In this case would the switch control voltages be -7V to turn the switch
off and >0V to turn the switch on?

michael fulbright
msf@as.arizona.edu

Newsgroup: sci.electronics
Document_id: 53523
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: A question about 120VAC outlet wiring..

In article <1qids1INNebl@chnews.intel.com> crichmon@sedona.intel.com (Chris Richmond) writes:
>
>In article <1993Apr14.193122.20818@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>> In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:

>> |> I'm considering modernizing some old wiring in my home, and
>> |> I need a little advice on outlet wiring.  Several outlets
>> |> are the old 'two prong' type, without the ground.  Naturally,
>> |> the wire feeding these outlets is 12/2, WITHOUT the ground
>> |> wire.  I noticed at the fusebox that some circuits have the
>> |> 12/2 with ground, and that on these circuits, the ground
>> |> wire was tied to the same bus as the neutral (white) wire.

>> This is contrary to the electrical code and should be fixed.

>Well, my house was built just last year, and the breaker box is wired the
>same way.  

	There SHOULD be a connection of the GROUND wire to a ground
in the breaker box.  There also should be a connection of the NEUTRAL
wire to a ground in the breaker box.  There should be no other 
place in the building where such a connection occurs (i.e. not in
any of the outlet boxes).

	The NEUTRAL (white) wire is a 'grounding conductor' for
the plug, and is NOT safe to touch, while the GROUND (green)
wire is a 'protective ground' and carries no current unless
some kind of electrical fault has occurred.  It's safe
to touch the protective ground, but not to touch the 
grounding conductor (because there is current in the grounding
conductor, its outlet-box end will not be at the same ground
potential as its breaker-box end).

	John Whitmore

Newsgroup: sci.electronics
Document_id: 53524
From: bill@thd.tv.tek.com (William K. McFadden)
Subject: Re: Cable TVI interference

In article <VL812B2w165w@inqmind.bison.mb.ca> jim@inqmind.bison.mb.ca (jim jaworski) writes:
>What happens when DVC (Digital Videon Compression) is introduced next 
>year and instead of just receiving squiggly lines on 2 or 3 channels 
>we'll be receiving sqigglies on, let's see 3*10 = 30 channels eventually.

Since the digital transmission schemes include error correction and
concealment, the performance remains about the same down to a very low
carrier-to-noise ratio, below which it degrades very quickly.  Hence,
digitally compressed TV is supposed to be less susceptible to interference
than amplitude modulated TV.

-- 
Bill McFadden    Tektronix, Inc.  P.O. Box 500  MS 58-639  Beaverton, OR  97077
bill@tv.tv.tek.com, ...!tektronix!tv.tv.tek.com!bill      Phone: (503) 627-6920
How can I prove I am not crazy to people who are?

Newsgroup: sci.electronics
Document_id: 53525
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Where to buy parts 1 or 2 at a time?

The pricing of parts reminds me of something a chemist once said to me:

"A gram of this dye costs a dollar.
It comes out of a liter jar which also costs a dollar.
And if you want a whole barrel of it, that also costs a dollar."

I.e., they charge you almost exclusively for packaging it and delivering
it to you -- the chemical itself (in that particular case) was a byproduct
that cost almost nothing intrinsically.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53526
From: wellison@kuhub.cc.ukans.edu
Subject: Re: electronic odometers

I had the insturment panel go out in my car (a 1990 Lincoln Contenintal) which
is a digital dash. They replaced the whole thing with a 1991 dash (thank god it
was under the warrenty ! :-) Anyway, the odometer was reading the exact milage
from the old panel. It must have a EEPROM of some sort in it that is up-dated.
Seems to me that removing the battery would erase it, but it doesn't. So I
guess they swapped the NVM chip (non-volitile memory) and installed it in the
new dash. No, they wouldn't let me have the old dash to tinker with :-(


-=-= Wes =-=-

Newsgroup: sci.electronics
Document_id: 53527
From: harry@neuron6.jpl.nasa.gov (Harry Langenbacher)
Subject: Re: Uninterruptible Power Supply

In article <NURDEN1.25.734866568@elaine.ee.und.ac.za> NURDEN1@elaine.ee.und.ac.za (Dale Nurden) writes:
>I'm wanting to build a simple UPS for my PC. ... sustain the computer long enough to complete 
>the current task and save, 5 to 10 minutes should be enough....
>I think, though I don't really need to keep the monitor active (I can try to 
>remember what to do) so maybe I can avoid a DC-AC inverter and just use a 
>battery to directly supply the motherboard and peripherals.

Now there's a good idea ! All you need is 20 amps DC for a few minutes, and
a good (wetware) memory (was I using wp or autocad or ...). I thought of the
same idea myself a few days ago. I've got a fairly new car battery that I take
along in my 4x4 when I go camping, and it sits around useless when I'm home.
I wish I could get a batteryless ups to use it with, or use it with a heavy
duty 5-volt regulator to supply the PC. But I guess you'd need -5v and -12v 
(and +12) too (2 more batteries ?).

An alternative would be to leave a 40 AMP battery charger hooked up to the battery
and run a 12vdc to 110vac converter running all the time, and when the power
goes out, voi-la ! the 110vac converter keeps on running off the battery ! and
then I could take the 110vac converter and my computer on the camping trips !-)


-- 
Harry Langenbacher 818-354-9513 harry%neuron6@jpl-mil.jpl.nasa.gov
FAX 818-393-4540, Concurrent Processing Devices Group, Jet Propulsion
Laboratory, M/S 302-231, 4800 Oak Grove Dr, Pasadena CA 91109 USA

Newsgroup: sci.electronics
Document_id: 53528
From: ali@cns.nyu.edu (Alan Macaluso)
Subject: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.


---
A l a n  M a c a l u s o		 	PURPLE MOON GIANTS
ali@cns.nyu.edu  				158 E. 7th. St. #B5
(212) 998-7837					NYC  10009
						(212) 982-6630

		
	        

Newsgroup: sci.electronics
Document_id: 53529
From: alung@megatest.com (Aaron Lung)
Subject: Re: what to do with old 256k SIMMs?

In article <1993Apr15.100452.16793@csx.cciw.ca> u009@csx.cciw.ca (G. Stewart Beal) writes:
>In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>>
>>	I was wondering if people had any good uses for old
>>256k SIMMs.  I have a bunch of them for the Apple Mac
>>and I know lots of other people do to.  I have tried to
>>sell them but have gotten NO interest.
>>
>>	So, if you have an inovative use (or want to buy
>>some SIMMs  8-) ), I would be very interested in hearing
>>about it.
>>
>One of the guys at work takes 20 of them, uses cyano-acrylate glue to make
>five four-wide "panels" then constructs a box, with bottom, to use as a
>pencil holder.
>

Or, if you've got some entreprenuerial (sp?) spirit, get a cheapy
clear plastic box, mount the simm inside, and sell it as a 'Pet SIMM'!

I'm sure there are *plenty* of suckers out there who would go
for it!

aaron



Newsgroup: sci.electronics
Document_id: 53530
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: A question about 120VAC outlet wiring..

olsen@vetmed.cvm.uiuc.edu (Aart_Olsen) writes:

>>|> I noticed at the fusebox that some circuits have the
>>|> 12/2 with ground, and that on these circuits, the ground
>>|> wire was tied to the same bus as the neutral (white) wire.
>>
>>This is contrary to the electrical code and should be fixed.
>>
>Sorry, but this is exactly according to the NEC.

No need to be sorry, I blew it on this one.  At the main breaker box
where there is a thick wire ground leading to the earth, both neutral
and ground are hooked to this bus.  In any other breaker box (or an
outlet box, etc.) the ground and neutral must not be connected together.



Newsgroup: sci.electronics
Document_id: 53531
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: mysterious TV problem -- source?

LLBGB@utxdp.dp.utexas.edu writes:
>Initial symptoms:
>-no picture or sound
>-CRT filament does NOT glow
>-flyback ticking as described abovew

>Discovered when hooked up the scope:
>-IF strip is not putting out audio or video signals
>-everything is making simple 20-30 Hz pulses
>-horiz out transistor collector (case of the TO-3) is a 20-30 Hz downgoing
>  sawtooth with ca. 15kHz ring at front end

>guys, WHAT"S GOING ON HERE?  Anyone seen this before?

What is happening is this:
1) You turn the TV on.
2) The horizontal output begins normal operation.  This powers up the
   high voltage and most of the rest of the circuitry.
3) A problem is sensed and the horizontal oscillator shuts down.
4) After it powers down the cycle repeats.

Things to check:
First check for a shorted high power component.  Your best bet is the vertical
output transistor(s) or, if there is one, the voltage regulator.  The most
common cause of this type of failure is too much current being drawn
somewhere.
Also look for shutdown circuits (which your TV may or may not have),
if you can find one that is shutting down the horizontal oscillator
then it shouldn't be too hard to find the problem from there.


Newsgroup: sci.electronics
Document_id: 53532
From: alung@megatest.com (Aaron Lung)
Subject: Re: What are some good Suppliers of Chips?

In article <1qihcl$9ri@usenet.INS.CWRU.Edu> ae454@cleveland.Freenet.Edu (Paul Simundza) writes:
>
>
>anyone know of any good supplier's of chips, one that could have almost
>any chip i need? I don't want to hunt down all the chips I may need so
>it would be greatly appreciated if anyone knows of a good distributor
>..
>thankyou
>

Paul,

Unfortunately, there are not too many retail outlets that'll stock
just about every chip made.  The stuff they will stock are the ones
that'll sell, like standard DRAM's, 80386's, 68000's, etc,etc.
i.e.  I cna't think of any 'one-stop-shopping' store.

The closest you can get is to pick up a copy of Byte magazine or
the Circuit Cellar, Popular Electronics, and the like and flip
through them.

Distributors like Wyle Electronics, Hamilton Avnet, Pioneer Electronics,
etc, etc, don't normally deal with end-users like ourselves where
we only a couple of everything...they only deal with people who buy
by the hundreds or more.  Each distributor represents and sells a variety of
different non-competing manufacturers.  What do I mean by this?
Suppose ABC Electronics sells Intel 80386's.  It's a pretty good
bet that they won't be selling any of AMD's 386's, or vice-versa.
They also can obtain just about *any* chip you want from a manufacturer
they represent.

Who knows?  You might be lucky to be able to buy from one of them.
But I'd be suprised if you do.  ALso bear in mind that the 1 or 2
qty prices they will charge you will be *much* greater than what
a mail order outlet will charge.

My advice?  If you're gonna be designing anything, try to stick
with off-the-shelf stuff.  You're going to get stuck if you use
too many esoteric parts sooner or later.

good luck,

aaron


Newsgroup: sci.electronics
Document_id: 53533
From: adler@netcom.com (Bruce Adler)
Subject: Re: IBM-PC XT switch settings

In article <1qk158$kcp@bigbird.hri.com> obrien@bigbird.hri.com writes:
>I just got an IBM-PC XT with no documents. Its a true
>IBM, and I was wondering if anyone had the definitions
>of the 2 8 position dip switches? 

SW8,SW7	number of 5.25" drives
0,0	1 drive
0,1	2 drives
1,0	3 drives
1,1	4 drives

SW6,SW5	type of display
0,0	reserved
0,1	40x25 color (mono mode)
1,0	80x25 color (mono mode)
1,1	mono 80x25

SW4,SW3	amount of memory on system board
	64k chips	256k chips
0,0	64k		256k
0,1	128k		512k
1,0	192k		576k
1,1	256k		640k

SW2	co-processor installed
SW1	loop on POST

Newsgroup: sci.electronics
Document_id: 53534
From: tsp@ccd.harris.com (Timothy S. Pillsbury)
Subject: need ACS tutorial and/or netlist examples


I recently ftp'd Al's Circuit Simulator (ACS) and I'm looking for
the tutorial which is mentioned in the Users Manual (but not found there).
I don't have any experience constructing a netlist (such as for SPICE)
and I need a little help.

The examples which come with ACS aren't explanatory about the translation
between schematic and netlist. Does anyone have the fabled "Tutorial"
or any other reference which could help me in constructing a netlist from
a schematic diagram?

(I also emailed Al himself but received no response yet. He's probably
 busy with his next release.)
-- 
-------------------------------------------------------------------------------
Tim Pillsbury          Internet:  tsp@ccd.harris.com
                          uunet:  uunet!ccd.harris.com!timothy.pillsbury
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53535
From: surfer@world.std.com (Internet Surfer)
Subject: New mailserver...soon...utopia-service

For all those who are interested and would like to discuss the popular
Secret Life..and/or other technical documentaries.. Please email me
as i am starting a newsgroup


-- 
jolt@gnu.ai.mit.edu	      |    Its not impossible, just improbable
johnp@pro.angmar.uucp         |            (Zaphod Beeblbrox)
bl298@cleveland.freenet.edu   |   N1NIG@amsat.org (Being a Ham is so grand)

Newsgroup: sci.electronics
Document_id: 53536
From: ardai@wizard.atb.teradyne.com (Michael Ardai)
Subject: Re: Source for carbide pc board drills?

In article <C5EJL7.LIn@news2.cis.umn.edu> Mike Diack <mike-d@staff.tc.umn.edu> writes:
-In article <C5DGG7.5ox@wang.com> , pvr@wang.com writes:
->   Who sells the special carbide drills used to drill pc boards?
->I am looking for sizes smaller than #60, #65 or #70 would be good.

-best deal i ever saw on carbides was at ELI electronics - Cambridge
-Mass. Quite close to MIT, #70 drills @ $5.00 for a box of 50. ELI are
-in the Boston fone book.

Actually, I think they are all #57.  Their phone number is 617 547 5005
and I will probably have some over at the MIT Flea this Sunday.
/mike


-- 
\|/     Michael L. Ardai     N1IST             Teradyne ATG Boston
--- -------------------------------------------------------------------------
/|\                    ardai@maven.dnet.teradyne.com

Newsgroup: sci.electronics
Document_id: 53537
From: cph@dmu.ac.uk (Chris Hand)
Subject: Cheap LCD panels & seeking info

Attention hardware hackers and bargain seekers!

I just bought a 640x200 pixel LCD panel for 25 UK pounds.  I have
a datasheet for a similar panel, but I'm looking for proper data.

If anyone can help with locating data for this device (before I start
with the routine on the phone to Hitachi and rummaging through the
library), then I'll pass on the source.

	Type: LM225 (Hitachi)
	Resolution: 640W x 200H (so can do 80x25 chars on 8x8 matrix)

Bought from:

	Greenweld Electronics Ltd
	27 Park Rd
	Southampton SO1 3TB, UK

	Tel. +44 703 23 63 63
	Fax. +44 703 23 63 07
	Email: Compuserve [100014,1463]

NB: I only just bought this!  I don't even know if it works!

	Price was 25 UK pounds including VAT (17.5%), which isn't
	payable if you're outside the EC.

Thanks for any info!


Chris

-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
Document_id: 53538
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: R/S Battery of the Month Club

In article <JWATERMA.93Apr14214858@jade.tufts.edu> jwaterma@jade.tufts.edu (Jason Waterman) writes:
>I talked to a friend who works for Radio Shack, and he said the deal
>with the Red Batteries were that they had too much lead in them.
>Condidering the Red Batteries had a life cycle shorter than a mayflies, 
>I think the EPA was worried about all those batteries being dumped out.

Pardon me, but why would carbon-zinc cells have any lead in them at all.
--scott


Newsgroup: sci.electronics
Document_id: 53539
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Do Analog Systems Need Ground Planes?

engp2254@nusunix1.nus.sg (SOH KAM YUNG) writes:

>I understand the need for a ground plane in a digital system. However, I
>would like to know if such a ground plane is also necessary in an analog
>system.
>
>(Note: this ground plane will not be connected, except at one point, to
>the signal ground).
>
>I keep getting conflicting answers over this. Does having a ground plane
>in an analog system help reduce noise also? My system only deals with
>low frequency signals (up to 100Hz only!!!).

Well, one reason for getting conflicting answers is that it depends on
what you want the ground plane to do.  A continuous conductor is a good 
electrostatic shield.  Do you have signals on your board that need
shielding rom other things?  This shielding won't do much good for magnetic
fields, unless you make it continuous around the circuit to be shielded,
like a Faraday cage.

The flip side of the coin:  if you are working with (very) high impedances,
you could end up with capacitances to the gound plane that cause problems.
You aren't likely to encounter this at 100Hz, but at 20kHz, it can be a
real problem (one that bit me once).


Newsgroup: sci.electronics
Document_id: 53540
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: what to do with old 256k SIMMs?

In article <C5JCH1.FrC@ulowell.ulowell.edu> wex@cs.ulowell.edu writes:
>In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
>|> >	I was wondering if people had any good uses for old
>|> >256k SIMMs.  I have a bunch of them for the Apple Mac
>|> >and I know lots of other people do to.  I have tried to
>|> >sell them but have gotten NO interest.
>
>We use them as Christmas tree decorations, the cat doesn't eat these.

Yes, but they don't look appropriate.  I much prefer used 833 tubes on
my tree.
--scott

Newsgroup: sci.electronics
Document_id: 53541
From: davidj@rahul.net (David Josephson)
Subject: Re: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

In <C5JJJ2.1tF@cmcl2.nyu.edu> ali@cns.nyu.edu (Alan Macaluso) writes:

>I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

>Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.


>---
>A l a n  M a c a l u s o		 	PURPLE MOON GIANTS
>ali@cns.nyu.edu  				158 E. 7th. St. #B5
>(212) 998-7837					NYC  10009
>						(212) 982-6630

>		


Without doing anything really tricky, the best I've seen is the
Burr-Brown INA103. Their databook shows a good application of this
chip as a phantom power mic pre.

>	        
-- 
------------------------------------------------------------------------
Josephson Engineering, San Jose California      MICROPHONES
Tel/ 408-238-6062  Fax/ 408-238-6022            INSTRUMENTATION
email:david@josephson.com  ftp info from: rahul.net /pub/davidj/

Newsgroup: sci.electronics
Document_id: 53542
From: ray@ole.cdac.com (Ray Berry)
Subject: Re: $25 network

zjoc01@hou.amoco.com (Jack O. Coats) writes:

>The same folks now have out LBL (Little Big Lan) for $75.  I think you
>get it for $50 if you already own $25 Network.  LBL works with Arcnet,
>parallel ports, and serial ports in any combination for up to 250 or so
>nodes.

    LBL now offers ethernet support also, although presently it is limited
to NE1000/NE2000 style boards.  LBL owners can get an update for $8.50.
-- 
Ray Berry kb7ht ray@ole.cdac.com  rjberry@eskimo.com  73407.3152@compuserve.com

Newsgroup: sci.electronics
Document_id: 53543
From: betts@netcom.com (Jonathan Betts)
Subject: Where to find CHEAP LCD displays?

Sci.E(E) netters:

I am setting out to build and market a small electronic device that 
requires an LCD display.  All of the analog electronics are working 
fine, I have ordered a PIC ICE (not vice versa) since the PICs are so 
cheap and low-power, but I am having a devil of a time finding any 
LCD displays in the 6-8 digit range that are priced as low as I need.  I 
am looking for somthing in the range of $1 in quantities of about 
1000-10,000.

Mainstream distributors like Almac cannot help me without a part 
number, or when they do look around for something in their line 
they find a $15 8-digit LCD.  Even Digikey's cheapest offering is $5 in 
quantity.

I know LCD displays like this must exist because I see whole 
calculators for sale for $4.99, meaning the retailer probably buys it 
for $3.50 and the wholesaler probably gets it for $2.50 or so.  This 
$2.50 includes assembly labor, packaging, sales, transportation, 
import duties, the case and keyboard, the PC Board, the processor 
chip, the solar cell --- and the LCD.  The LCD can't cost much.

If anyone could put me in touch with some manufacturers and/or 
distributors that handle such things I would be much obliged.

-Joe Betts
betts@netcom.com


P.S.  I have tried tearing apart several cheap consumer devices that 
have LCDs only to find that the LCDs are unlabelled.  Has anyone else 
had better luck with this strategy?

Newsgroup: sci.electronics
Document_id: 53544
From: morrow@cns.ucalgary.ca (Bill Morrow)
Subject: Amplifier into CD-ROM earphone plug ?

We have a Sun CD-ROM drive which I would like to play audio CD's in.
I have an old 10 watt amplifier which works fine when connected to a
junk "Walkman" style AM/FM radio. This amp ties the common path of the
earphone connection to ground.

However, it doesn't work with my Sony Walkman cassette player, or the CD drive,
it produces of loud low-frequency tone. Obviously Sony doesn't ground
the earphone output common. Does anyone have specs on the CD drive's 
output? Will an audio transformer help? What are others using to
play there CD's in the Sun drive so that more than one can listen?

Thanks for the help.
-- 
Bill Morrow    Clinical Neurosciences, University of Calgary
e-mail: morrow@cns.ucalgary.ca voice: (403) 220-6275 fax: (403) 283-8770 
3330 Hospital Drive NW Calgary, Alberta, CANADA T2N 4N1

Newsgroup: sci.electronics
Document_id: 53545
From: oxenreid@chaos.cs.umn.edu ()
Subject: Re: Radar detector DETECTORS?

In <1993Apr06.173031.9793@vdoe386.vak12ed.edu> ragee@vdoe386.vak12ed.edu (Randy Agee) writes:

>So, the questions are -
>  What do the radar detector detectors actually detect?
>  Would additional shielding/grounding/bypassing shield stray RF generated by
>  a radar detector, or is the RF actually being emitted by the detector
>  antenna?
>  Are any brands "quieter" than others?

Ok, so your a HAM.   Well, tune in 10.7Mhz or 455Khz.  These numbers sound 
like some you have herd before?   Thats right, you guessed it, they are 
common IF numbers.   Every Super-Het receiver has a local oscillator(s)
which generates an IF.  This is what your detector detector is detecting (the
local oscillator). 

Some of these have two or more local oscillator which generate more ways to
receiver you.  If you want to receiver something at say 10.525Ghz you must 
generate a local oscillator signal of 10.525Ghz - 10.7Mhz = your local osc
frequency.  This 10.7Mhz IF is then fed into a normal AGC ckt.  
The detector is keyed uppon the AGC voltage (your mileage may vary).  Since
the AGC is a negative feed back device, a positive voltage sets off a ...
I think you get the picture.


Newsgroup: sci.electronics
Document_id: 53546
From: kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan)
Subject: subliminal message flashing on TV



Hi.  I was doing research on subliminal suggestion for a psychology
paper, and I read that one researcher flashed hidden messages on the
TV screen at 1/200ths of a second.  Is that possible?  I thought the
maximum rate the TV was even capable of displaying images was 1/30th
of a second.  (or 1/60th of a second for an image composed of only odd
or even scan lines)

- Rich
  kennehra@logic.camp.clarkson.edu

Newsgroup: sci.electronics
Document_id: 53547
From: urbina@novax.llnl.gov
Subject: Telcom wiring question...need help


I've got two lines coming into my apartment. Two different telephone numbers.
When I ordered the second line installed, instead of bringing out another 4
wire bundle, the telco just connected up to my yellow and black wires. So I
have one line on red & green and the other on yellow & black.

Today I was monitoring the voltage on both lines. I had a voltmeter across
the red and green and read back 52 volts. I then lifted up the receiver on my
second line.(black & yellow wires) The voltage dropped to 31 volts on the first
line. (red & green wires) I repeated this experiment with the second
line(monitoring black & yellow and lifting the handset off the cradle on the
red and green line.) It also dropped to 31 volts. 

Why is this ? I thought these were separate lines.

Next I went to the 66 block and disconnected the blue and white lines coming in
from the telco cable. I then disconnected all the phones in my apartment and
went back to the 66 block and did some resistance measurements. Both lines read
open.

I'll appreciate any help on this. Is this considered normal ?

Guy Urbina

Urbina@novax.llnl.gov
 

Newsgroup: sci.electronics
Document_id: 53548
From: mwtilden@math.uwaterloo.ca (Mark W. Tilden)
Subject: BEAM Robot Olympic Games next Week in Toronto.


One week to the Robot Olympic games.  Fire up the mechanoids for combat
and come on down.

Competitors please note that there has been a slight change; the registration
desk will now be in the forward building of the Science Centre rather than
in the main competing hall.  When you arrive, please go to this desk.  Those
that have pre-registered by real-mail will find badges waiting.

Is all.  See you here.


-- 
Mark Tilden: _-_-_-__--__--_      /(glitch!)  M.F.C.F Hardware Design Lab.
-_-___       |              \  /\/            U of Waterloo. Ont. Can, N2L-3G1
     |__-_-_-|               \/               (519)885-1211 ext. 2454 
"MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"

Newsgroup: sci.electronics
Document_id: 53549
From: klg@mookie.mc.duke.edu (Kim Greer)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <1993Apr15.044636.29924@slcs.slb.com> dcd@se.houston.geoquest.slb.com (Dan Day) writes:
>That's scary -- if there's a way to set an arbitrary mileage figure
>into the odometer, you can't trust *any* odometer reading, even
>if you can prove that the odometer itself is the same one that
>came on the car originally.

  I was wondering if anyone can shed any light on just how it is that these
electronic odometers remember the total elapsed mileage?  What kind of
memory is stable/reliable enough, non-volatile enough and independent enough
(of outside battery power) to last say, 10 years or more, in the life of a
vehicle?  I'm amazed that anything like this could be expected to work for
this length of time (especially in light of all the gizmos I work with that
are doing good to work for 2 months without breaking down somehow).

Side question:  how about the legal ramifications of selling a used car with
a replaced odometer that starts over at 0 miles, after say 100/200/300K
actual miles.  Looks like fraud would be fairly easy - for the price of a
new odometer, you can say it has however many miles you want to tell the
buyer it has.

Thanks for any insight.


Kim Greer                       
Duke University Medical Center		 klg@orion.mc.duke.edu
Div. Nuclear Medicine  POB 3949		 voice: 919-681-5894
Durham, NC 27710  		         fax: 919-681-5636

Newsgroup: sci.electronics
Document_id: 53550
From: tod@cco.caltech.edu (Tod Edward Kurt)
Subject: data pods (10248B) for HP logic analyzer (1615A)?!?

Anyone out there in netland have a spare data pod or two from an old 
1615A Hewlett Packard logic analyzer?  If you do, I'd like to buy it off
of you.  The pod's part number is 10248B.

As a side note, anyone know of any good surplus dealer or other organization
that would carry wayward logic analzer pods?

				Thanks a byte,
						Tod
							tod@cco.caltech.edu


Newsgroup: sci.electronics
Document_id: 53551
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Exploding TV!

Sounds like the picture tube lost vacuum.  This would cause the filament
to ignite and could actually turn the tube from a vacuum to a pressure
vessel, followed by an explosion when the neck assembly (mostly likely
cracked to begin with) blows off.  During the whole sequence of events,
the other circuits may continue functioning, which accounts for not
losing sound.

Newsgroup: sci.electronics
Document_id: 53552
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Scope questions


	Greetings. I've been seeing the word "storage" mentioned
	around oscilliscopes but I'm curious, what does it mean?

	If my life depended on it, I'd say that it's a scope that
	uses long-persistance phosphor to keep the successive
	taces on the screen for some unit of time - "store" them.
	Do I get to live?

	Also, I've been shopping for a decent, used, [old] scope
	since my Tek 514A (portable...NOT!) and my Heathkit O-1000
	are all single trace and I need more... like 2 or 3 and at
	least 50MHz (maybe 100...)

	During my shopping at hamfests etc. I've run into the 
	problem of "old scope" terminology. I can imagine what
	a "mainframe" and "plug-in" are but some things like
	the above "storage", "coax input" (Hey, where do I get a 
	probe that fits this? I had to fiddle with mine for a week 
	before I got anything resembling "a good trace" - they all
	come with BNC connectors!), "unblanking" (huh?), and, oh,
	just like my 514 manuals, MANY changes were made along the
	way to the schematic - scopes, even with IDENTICAL model 
	numbers, have different (better?) response/performance than
	others - how can I pick the better one? Does the rule of the
	higher SN the better apply?

	Take care.
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
Document_id: 53553
From: s5600043@nickel.laurentian.ca
Subject: Re: CD player going wonky - advise needed !

In article <1993Apr13.150525.17978@nessie.mcc.ac.uk>, sl@nessie.mcc.ac.uk (Stuart Lea) writes:
> Hello,
> 	I've got a problem with my CD player (SONY CDP-35) in that it refuses
> to play discs - more than a minor inconvenience!  The player itself doesn't
> recognise that there is a disc in.  It's an intermitant problem, but one 
> that is becoming more frequent.
> 
> 	Is this a common problem with older CD players and, if so, what
> can be done to rectify it ?  If there is no obvious answer, how can I begin to 
> start fault finding.  To start off with, How does thet mach recognise that 
> there is a disc in in the first place ?


My experience is that the CD drawer becomes a bit loose, and the CD either skips
or can't be read.  Try seeing if all the screws that hold down the drawer
assembly are tightened properly.  Other than that, my next guess would be one of
the motors.  Hope this helps.
Dave Haans, Laurentian University, Sudbury, Ontario.

Newsgroup: sci.electronics
Document_id: 53554
From: rogerw@world.std.com (Roger A Williams)
Subject: Re: Adcom cheap products?

mdonahue@amiganet.chi.il.us (Mike Donahue) writes:


>I do NOT know much about Adcom Mobil Audio products, but I DO know for a fact
>that ADCOM does NOT make its own "High End" Home Audio Equptment and that 80%+
>of it comes directly out of Tiawan...

Like most high-volume manufacturers, Adcom has most of its PC boards
assembled off-shore (in their case, mostly in the far east).  Final
assembly _and testing_ are done in East Brunswick.

The products are, and have always been, designed entirely in the US;
by their own staff and by audiophile gurus like Walter Jung.  Adcom
also tends to prefer American and European components over their
Japanese/Far East equivalents.

Off-shore assembly is one reason that Adcom is able to make products
that perform as well as those from people like Audio Research and Van
Alstine (and better than Hafler and Forte'), but at a much lower cost.

Of course, if your musical diet consists mostly of Rock, you might
prefer components from Kenwood or Pioneer...

Roger Williams		| "Most great discoveries are made
rogerw@world.std.com	|  by accident: the larger the
consulting engineer	|  funding, the longer it takes to
Middleborough, Mass.	|  have that accident."

Newsgroup: sci.electronics
Document_id: 53555
From: alung@megatest.com (Aaron Lung)
Subject: Re: Telephone on hook/off hok ok circuit 

In article <1993Apr15.144826.4607@bnr.ca> moffatt@bnr.ca (John Thomson) writes:
>: >> >Just a thought of mine here:
>: >> >Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 1
>: >> >How about an LED in series with a zener say around 30V.
>: >> >On-hook = LED on
>: >> >Off-hook = LED off.
>: >> >Would this work? If anyone tries/tried it, please let me know.
>: >>
>: >> Aye, there's the rub -- if you draw enough current to light an LED, the
>: >> equipment at the phone company will think you've gone off hook.
>: >> In the on-hook state you're not supposed to draw current.
>: >
>: >Which means you should just use your Digital VoltMeter. You can use an
>: >old VOM but the phone company equipment can detect that and might think
>: >there's something wrong with the cable.
>: >
>: 
>: Look Guys, what's the problem here?  If you want a light that goes on when 
>: the 'phone is *Off* hook, all you need it to run it in *series* with the 
>: line, as I mentioned in my previous post.  If you want a light that goes on 
>: when the 'phone is *on* hook, all you need is a voltage threshold detector.
>
>If you're going to do the series Diode thing (which is the easiest), just
>make sure that the LED can take the current (I can't recall it off-hand, but
>it's something like 100mA or more?)

Careful now folks... Also consider the 90VAC+ @20Hz that is forced on ring
and tip when the phone's supposed to ring!  Even with a simple zener
and LED setup, you might end up with some carbon real quick.  Whatever
scheme you use, make sure you've got at least 200V-rated components on 
the frontend.

Also remember that, if I'm not mistaken, the phone line is a 600ohm
equivalent circuit.  Any current you draw from the 48V or so gets
dropped across that 600ohms.  That's fine until you're down to roughly
12V, when Ma Bell considers it to be off-hook.  But dropping it that
far down is probably a big no-no.

The easiest implementation to accomplish the above??

    tip  ------->|-----\/\/\/\-----+----------+
              rectifier  resistor  |          |
              diode                |          \ 
                                   V          /
                          zener  /---/        \  resistor
                                   |          /
                                   |          |
                                   |          V   LED
                                   |         ---
                                   |          |
    ring --------------------------+----------+

This is only a suggestion...go ahead and blow holes in it, but you
get the idea.  Choose a high-efficiency LED so you don't need much
current to get it to light up.  Choose values for the other components
as required.

aaron


Newsgroup: sci.electronics
Document_id: 53556
From: alung@megatest.com (Aaron Lung)
Subject: Re: Uninterruptible Power Supply

In article <1qk724INN474@hp-col.col.hp.com> cab@col.hp.com (Chris Best) writes:
>I'm no expert at UPS's, but you said something that made it sound like
>you didn't realize something.  On a typical UPS (well, on ours, anyway),
>there is NO switchover from AC to DC.  All the protected equipment is
>ALWAYS running from the batteries (via an inverter), with the usual 
>condition of also having them on charge.  If the power fails, big deal - 
>the computers never see it (until the batteries start to droop, but 
>there's something like 60 car-sized batteries in that cabinet, so it 
>takes a while).
>
>If you were gonna run the guts on straight DC instead of an inverter,
>why not do it all the time?  Then there'd be no switchover to screw
>things up, and no having to sense the failure fast.  Just keep the DC
>on charge when the power is on, and it'll be there in zero time when
>you "need" it.
>

Actually, it's a bit more complicated than that...I sounds to me,
your UPS takes in AC, rectifies it to DC to charge the batteries, and
then takes the battery DC and chops it to AC again, feeding your
equipment.  This approach is the easiest and cleanest way to
switchover from the mains to battery once your power kicks out since,
as you mentioned, nothing will know about what happened down the line.

Another way to do the UPS scheme is to use the mains until you
lose power, and then kick in the battery backup with it's inverter to
replace the lost power.  The problem here is the switchover time and
you've got to resync the AC in no time flat.

Unfortunately, most everything is built around the assumption that
AC is available, so the UPS guys have to provide and AC output to
be usable...ya sorta have to make it work with what there already.

Similar story with our telephone system.  It was first invented back
in the 1800's.  We're still using the same damn system (media) as they
did back then.  If I have a phone from back then, I can assure you
it'll work on today's phone system.  It costs too much to overhaul
everyone to a new system, so they make it work with what is out there.

.

Newsgroup: sci.electronics
Document_id: 53557
From: alung@megatest.com (Aaron Lung)
Subject: Re: Exploding TV!

In article <1qk4hj$qos@vtserf.cc.vt.edu> prasad@vtaix.cc.vt.edu (Prasad Ramakrishna) writes:
>I had a GE Emerson 13" color TV for about 3 years and one fine day,
>while we were watching something (I doubt if the program was the cause),
>we heard a mild explosion.   Our screen went blank but there was sound,
>so we thought, 'oh we have special effects on the program'.  But soon
>the sound stopped and smoke started to appear at the back of the TV.
>The brilliant EEs we are, we unplugged the TV and called customer service
>only to be thrown around by please hold, I will transfer u to blah blah..
>  Finally we abandoned the idea of trying to fix the TV and got a new one
>(we wanted a bigger one too!).
> After all the story, what I wanted to know is: Is my problem an isolated
>incident or a common one? (I recall reading about Russian TVs exploding, but
>not here, in the US). Why would the picture tube explode or even smoke?
> I still have the left over TV set, I might dig into it this summer. Any
>idea where I can get parts for these things? (probably will cost more than TV).
>

Heh, heh, heh, heh....I laugh because I have the same damn TV, and it
did the same thing!  Actually it is a Goldstar, but it's essentially the
same TV and electronics--just a different face plate and name.

#1.  Fortunately, TV tubes don't explode.  I'd think the TV mfrs want
to make this possibility remote as possible.  If at all, they'll 
*implode* and the glass that blows out would be the result of the
glass boucing off the back of the tube due to the implosion. In any
case, don't kick it around! :-) 

#2  I fixed the TV after getting a hold of some schematics.  It turned
out to be a blown 2W resistor feeding the flyback transformer.  I guess
the original resistor was a bit too small to dissipate the heat it
created, burning itself out.  I checked to make sure the flyback wasn't
shorted or anything first!  Oh, luckily, I had a resistor handy lying
around that had just the right value for what I needed.  I can't see it
being more than 50 cents!.

Well, needless to say, the TV still works today.  So go get a set of
schematics and have some fun...just don't get shocked poking around
the flyback.


Newsgroup: sci.electronics
Document_id: 53558
From: <LEEK@QUCDN.QueensU.CA>
Subject: Re: ADC card for computer

In article <1qi8e3$b5e@lll-winken.llnl.gov>, you say:
>
>I would like to digitize the output of a SQUID magnetometer (range -10 V
>to +10 V) and do digital signal processing in a computer, say a Macintosh
>II or a 486 PC.  I would like a good 16 bit ADC with good linearity and a
>high conversion speed, at least 50 kHz, preferably 200 kHz.  Other concerns
>
>(2)  Must I use an ADC external to my computer to avoid digital noise
>     feedback into my sensitive SQUID electronics?

Might be a good idea...  The resolution you requested is about 0.3mV
In order to get what you've paid for, noise level better be lower than
that.  It is kind of hard to do it in a noisy box like you can expect
inside a PC.

Before you pay $$$ for a PC card, test it out by sampling a low
distortion sine wave (I think there is a sine wave on a CD.  Digital
Domain ?  There are possibly other low THD sources)  Run the digitized
waveform through a FFT transform and take alook at the noise floor on
the spectrum.  That's should give you a good indication of the design.
(That's what I am doing to test a data acquistion system I have designed
- I got the idea from MAXIM data sheet.)

If you can live with 14 bit resolution, I would recommend looking at
the MAX121 from MAXIM.  It is a high speed (308KHz) complete
sampling A/D with DSP interface.  The input range is +/- 5V and it
uses a serial interface (which can easily be optically isolated
from the computer to elinimate a major noise source)  The Analog design
guide I got from them shows a -100db noise level.  They claim a -77db
max (-85 typ.) THD.  Looks pretty good for the $12 @ 1000 pieces

A evaluation kit is available.  Might want to give these nice folks a
call.  1-800-998-8800 or fax: (408)737-7194 and (408) 737-7600 ext4000
for application assistance.

This assumes that you can build your own DAS and write your own software.
(Hey you can get the MAX121 as a free sample just by calling the 1-800 #)

>I would appreciate discussion of your personal experience with a Mac or PC-
>based ADC system.

I would recommend you to find out the resolution that can be gotten out
of your system by looking at the noise level, otherwise you might be
throwing out your money.

>Charles Cunningham
>cec@imager.llnl.gov

K. C. Lee
Elec. Eng. Grad. Student

I have no connection with MAXIM except I do in general recommend
companies that give samples to students to others.  I feel they
deserve that for being nice to me.

Newsgroup: sci.electronics
Document_id: 53559
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: what to do with old 256k SIMMs?

In article <120466@netnews.upenn.edu>, jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
|> 
|> 	I was wondering if people had any good uses for old
|> 256k SIMMs.  I have a bunch of them for the Apple Mac
|> and I know lots of other people do to.  I have tried to
|> sell them but have gotten NO interest.
|> 
|> 	So, if you have an inovative use (or want to buy
|> some SIMMs  8-) ), I would be very interested in hearing
|> about it.

The most practical use I've seen for them is as key ring ornaments :-)

JohnH

Newsgroup: sci.electronics
Document_id: 53560
From: sknapp@iastate.edu (Steven M. Knapp)
Subject: Re: Radar detector DETECTORS?

In article <oxenreid.734127163@chaos.cs.umn.edu> oxenreid@chaos.cs.umn.edu () writes:
>In <1993Apr06.173031.9793@vdoe386.vak12ed.edu> ragee@vdoe386.vak12ed.edu (Randy Agee) writes:
>
>>So, the questions are -

>>  Are any brands "quieter" than others?

Yes some radar detectors are less detectable by radar detector
detectors. ;-)

Look in Car and Driver (last 6 months should do), they had a big
review of the "better" detectors, and stealth was a factor.
________________________________________________________________________ 
Steven M. Knapp                             Computer Engineering Student
sknapp@iastate.edu                  President Cyclone Amateur Radio Club
Iowa State University; Ames, IA; USA      Durham Center Operations Staff

Newsgroup: sci.electronics
Document_id: 53561
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Subject: Re: making copy of a Video tape

>There are devices you can buy and/or make.  Look in Radio & Popular 
>Electronics mags for the devices.  If all else fails, you can build one 
>using the curcuit design from the Dec. '87 issue of Radio Electronics.

My very favorite ad for such a device is on the back of the latest
Damark catalog.  Quoting from memory:

[Big flashy type]
"Dual deck VCR copies any tape -- Even those that are copy protected!*"

(And underneath the ad in very small print: *This device is not intended
for making illegal copies of copyrighted material.)

:-)

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
Vote straight ticket Procrastination party Dec. 3rd!

Newsgroup: sci.electronics
Document_id: 53562
From: russotto@eng.umd.edu (Matthew T. Russotto)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <1993Apr14.174857.28314@porthos.cc.bellcore.com> dje@bmw535.NoSubdomain.NoDomain (Don Eilenberger) writes:
}In article <1993Apr14.153740.18542@nimbus.com>, jimiii@nimbus.com (Jim Warford) writes:

}|>  There are two simple procedures for alterating any odometer.
}|> 
}|> 1. Mechanical driven odometer:
}|>     Remove the speedo cable from the transmission.
}|>     Attach a drill and run at max speed until the speedo turns over.
}|>     Continue until the desired mileage is reached.
}|> 
}|> 2. Electronically driven odometer:
}|>     Remove the sensor wire from the sensor.
}|>     Attach the Calibration out signal from an Oscope to the wire.
}|>     Run until the speedo turns over and attains the desired mileage.
}
}Dear Faster.. I kinda wonder.. have you ever tried version 2? On what?
}Since the sensor wire on a BMW feeds also into the computer.. and we
}don't know what signal voltage is expected from it.. bad things
}*could* happen... also since we don't know the pulse rate, we
}may damage the analog part of the speedo (yes.. BMW uses a combined
}instrument.. speed in analog, trip and total milage is digital) with
}the needle pegged up against the 160MPH stop..
}
}Just a thought...

You've got the oscilliscope, so you connect it up to the sensor wire
and measure this stuff.  That way you know what it expects.

-- 
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
Some news readers expect "Disclaimer:" here.
Just say NO to police searches and seizures.  Make them use force.
(not responsible for bodily harm resulting from following above advice)

Newsgroup: sci.electronics
Document_id: 53563
From: ritterbus001@wcsub.ctstateu.edu
Subject: Re: Picking up cable tv with an aerial.

In article <gyJX2B2w165w@inqmind.bison.mb.ca>, dino@inqmind.bison.mb.ca (Tony stewart) writes:
> jfsenior@unix1.tcd.ie (John Senior) writes:
> 
>> Recently, I discovered that it was possible to receive cable
>> tv through the telescopic aerial on the top of my tv.
>> The nearer this aerial is moved to the cable (which I am not
>> connected to) which runs under the eaves of the house the better
>> the signal.  Now, I was wondering how can I improve the signal?
>> Is it possible to improve the signal significantly? (some channels
> 
> CABLE EGRESS or emanations if you will are being radiated at free space 
> impedance from cables that may be harmonically realated to certain 
> channels and therfore the standing waves at 1/4 wave will transfer 
> efficiently. Also your antenna (a loose monopole) is also harmonically 
> tuned and will be more efficient at 1/2 wavelength multiples.
> 
> Your best bet for this research is to use a tuned YAGI antenna to get the 
> gain you need. (Std TV roof antenna type) The dipoles should be parallel 
> to the radiating cable. A pre-amp doesn't help significantly in my 
> experience in most cases.
> 
> dino@inqmind.bison.mb.ca
> The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Wow, what a concept!  Does anybody want to speculate on how this
"non-connection" would fit into the theft of cable services laws?
It seems to me that unless this case is specifically written into
the legislation that the cable company would not have a leg to
stand upon in court.

Does anybody out there have any specific legal knowledge on this?

Jim Ritterbusch
ritterbus001@wcsu.ctstateu.edu    - or - ne22@radiomail.net  (temp, rf)
There is an art, the Guide says, or rather a knack to flying.  The
knack lies in learning how to throw yourself at the ground and miss.


Newsgroup: sci.electronics
Document_id: 53564
From: doherty@coolpro.melpar.esys.com (Kevin Doherty)
Subject: Hard Drive Component Costs

  Does anyone have some information on the relative fraction of the final
cost of each component in an average hard drive?  For instance, I'm pretty
sure the heads and the platters are the most expensive parts, with the
assembly costs running a close third.  Cost of the electronics is likely
in the noise.
  Any hard numbers ($$ or percentage)?  Thanks.


+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| Kevin Doherty           E-Systems/Melpar Division   doherty@melpar.esys.com |
| Principal Engineer      Falls Church, VA 22046      (703) 560-5000x2659     |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
-- 
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| Kevin Doherty           E-Systems/Melpar Division   doherty@melpar.esys.com |
| Principal Engineer      Falls Church, VA 22046      (703) 560-5000x2659     |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+

Newsgroup: sci.electronics
Document_id: 53565
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Radar detector DETECTORS?

alee@bmerh794.bnr.ca (Louis Leclerc) writes:

> 
> In article <34263@oasys.dt.navy.mil> you write:
> >VA, CT, Wash DC  and I think BC Canada where I've heard they actually
> >use Radar detector detectors.
> 
> Nope, not in British Columbia.  Detectors are legal here in BC, I've even
> got one.
> 
> In Alberta and Ontario they're illegal, and detection devices are sometimes
> used.  I've heard the police in Ontario prefer a much more direct method of
> detection.  Just trigger the radar gun, watch for people slamming on the
> brakes, and search the car.
> 
> 
> David Lee
> leex@sfu.ca
> 


They are illegal here in Manitoba as well though I don't know what 
methods are used to detect them.

It has always amazed me with the way the laws work.  It is not illegal to 
sell them here in Manitoba, only to have them within a vehicle.  (Last I 
heard, they don't have to be installed to be illegal.)

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 53566
From: mkilpela@mtu.edu (Mark E. Kilpela)
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>,
crisp@ecsvax.uncecs.edu (Russ Crisp) wrote:
> 
> Hello
> I'm considering modernizing some old wiring in my home, and
> I need a little advice on outlet wiring.  Several outlets
> are the old 'two prong' type, without the ground.  Naturally,
> the wire feeding these outlets is 12/2, WITHOUT the ground
> wire.  I noticed at the fusebox that some circuits have the
> 12/2 with ground, and that on these circuits, the ground
> wire was tied to the same bus as the neutral (white) wire.
> 
> SO..  Here's my question.  It seems to me that I'd have the
> same electrical circuit if I hooked the neutral[D[D[D[D[D[D[D[D[D[D[Da jumper from the neutral
> over to the ground screw on new 'three prong' grounding outlets.
> What's wrong with my reasoning here?  

First, it will not pass a National Electrical code inspection.
Secondly, The neutral wire is current carrying and the ground wire
shouldn't be, or only during a fault condition.

The reason the neutral and ground are tied together in the panel is the
tranformer on the power pole has a grounded center-tap secondary, with the
grounded center-tap the neutral.  This gives 120v to neutral(ground) from
each side of the transformer and 240v across the transformer.  So in effect
the neutral and ground should be at the same potential. 

------------------------------------------------------------------
Mark E. Kilpela              email mkilpela@mtu.edu
Michigan Technological University
School of Technology
------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53567
From: swalker@uts.EDU.AU (-s87271077-s.walker-man-50-)
Subject: What do Nuclear Site's Cooling Towers do?



I really don't know where to post this question so I figured that
this board would be most appropriate.
I was wondering about those massive concrete cylinders that
are ever present at nuclear poer sites. They look like cylinders
that have been pinched in the middle. Does anybody know what the
actual purpose of those things are?. I hear that they're called
'Cooling Towers' but what the heck do they cool?
I hope someone can help 



Newsgroup: sci.electronics
Document_id: 53568
From: jeh@cmkrnl.com
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
> I'm considering modernizing some old wiring in my home, and
> I need a little advice on outlet wiring.  Several outlets
> are the old 'two prong' type, without the ground.  Naturally,
> the wire feeding these outlets is 12/2, WITHOUT the ground
> wire.  I noticed at the fusebox that some circuits have the
> 12/2 with ground, and that on these circuits, the ground
> wire was tied to the same bus as the neutral (white) wire.
> 
> SO..  Here's my question.  It seems to me that I'd have the
> same electrical circuit if I hooked the jumper from the neutral
> over to the ground screw on new 'three prong' grounding outlets.
> What's wrong with my reasoning here?  

No.  No.  NOOO!!!

The ground (green) wire is for safety.  No current is supposed to flow in it
under normal conditions.  This means that there's normally no voltage drop in
it either.  It is supposed to be safe to touch the ground wire... even if
you're grounded in some other way at the same time.  

The neutral (white) wire is, as Dave Vanderbyl correctly said, the return for
the hot wire.  Since current flows in it, there's a voltage drop.  If you
plug a heavy load into a properly-wired grounded outlet, you can commonly 
measure a volt or so of difference between neutral and ground.  

They are supposed to be connected together at the breaker panel... but nowhere,
repeat NOwhere, else.  (Well, almost.  There are strange exceptions for things
like sub-panels.)

What you CAN do if you want three-prong outlets without additional wiring is 
to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
depending on where you are putting your new outlet(s), a GFCI may be *required*.

There is a FAQ on electrical wiring, posted regularly to rec.woodworking and
news.answers.  It goes into great detail on these issues (including GFCIs) and
you should probably read it before asking any more questions.  I'll mail a copy
to you, append a copy here, and will ask the writers to cross-post it here in
the future. 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055


Newsgroup: sci.electronics
Document_id: 53569
From: jeh@cmkrnl.com
Subject: Electrical wiring FAQ (was: A question about 120VAC outlet wiring..

Since electrical wiring questions do turn up from time to time on
sci.electronics (and the answers aren't always apparent, even to those skilled
in electronics), I am hijacking the following FAQ and posting a copy here. 
I've asked the writers to cross-post to sci.electronics in the future. 

	--- jeh@cmkrnl.com


X-NEWS: cmkrnl news.answers: 6685
Newsgroups: misc.consumers.house,rec.woodworking,news.answers,misc.answers,rec.answers
Subject: Electrical Wiring FAQ
Message-ID: <wirefaq_733900891@ecicrl>
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Date: 4 Apr 93 05:21:49 GMT
Reply-To: wirefaq@ferret.ocunix.on.ca (Wiring FAQ commentary reception)
Followup-To: poster
Expires: 2 May 93 05:21:31 GMT
Organization: Elegant Communications Inc., Ottawa, Canada
Summary: A series of questions and answers about house wiring
Approved: news-answers-request@mit.edu
Supersedes: <wirefaq_732691289@ecicrl>
Lines: 1524

Archive-name: electrical-wiring
Last-modified: Sun Feb 21 16:56:10 EST 1993

	    Frequently Asked Questions on Electrical Wiring

		Steven Bellovin (smb@ulysses.att.com)
		Chris Lewis (clewis@ferret.ocunix.on.ca)

	    Comments to (automatic if you reply to this article):
		    wirefaq@ferret.ocunix.on.ca

This FAQ is formatted as a digest.  Most news readers can
skip from one question to the next by pressing ^G.

Answers to many other topics related to houses can be obtained from
the misc.consumers.house archive; send an empty piece of mail to
house-archive@dg-rtp.dg.com for information.

Changes to previous issue marked with "|" in left column.  Watch
particularly for "NEW" in the Questions list for new or substantively
changed answers.

Note that this is now a registered FAQ - cross-posted to news.answers
and should appear in the FAQ list of lists.

Subject: Questions answered in this FAQ

	Introduction/Disclaimers
	What is the NEC?  Where can I get a copy?
	What is the CEC?  Where can I get a copy?
	Can I do my own wiring?  Extra pointers?
	What do I need in the way of tools?
	What is UL listing?
	What is CSA approval?
	Are there any cheaper, easier to read books on wiring?
	Inspections how and what?  Why should I get my wiring inspected?
	My house doesn't meet some of these rules and regulations.
	A word on voltages: 110/115/117/120/125/220/240
	What does an electrical service look like?
	What is a circuit?
	"grounding" versus "grounded" versus "neutral".
	What does a fuse or breaker do?  What are the differences?
	Breakers?  Can't I use fuses?
	What size wire should I use?
	Where do these numbers come from?
	What does "14-2" mean?
	What is a "wirenut"/"marrette"/"marr connector".  How are they used?
	What is a GFI/GFCI?
	Where should GFCIs be used?
	Where shouldn't I use a GFCI?
	What is the difference between a GFCI outlet and a GFCI breaker?
	What's the purpose of the ground prong on an outlet, then?
	Why is one prong wider than the other?  Polarization
	What kind of outlets do I need in a kitchen?
	Where must outlets and switches be in bathrooms?
	What is Romex/NM/NMD?  What is BX?  When should I use each?
	Should I use plastic or metal boxes?
	Junction box positioning?
	Can I install a replacement fixture?
	What does it mean when the lights brighten when a motor starts?
	What is 3 phase power?  Should I use it?  Can I get it in my house?
	Is it better to run motors at 110 or 220?
	What is this nonsense about 3HP on 110V 15A circuits?
	How do I convert two prong receptacles to three prong?
	Are you sure about GFCIs and ungrounded outlets?
	    Should the test button work?
	How should I wire my shop?
	Underground wiring
	Aluminum wiring
	I'm buying a house!  What should I do?
	What is this weird stuff?  Old style wiring
	Where do I buy stuff?


Subject: Introduction/Disclaimers

	Although we've done a fair bit of wiring, we are not
	electricians, and we cannot be responsible for what you do.  If
	you're at all uncertain about what is correct or safe, *don't
	do it*.  Contact someone qualified -- a licensed electrician,
	or your local electrical inspector.  Electricity is no joke;
	mistakes can result in shocks, fires, or electrocution.

	Furthermore, our discussion is based on the U.S. National
	Electrical Code (NEC) and the Canadian Electrical code (CEC).
	To the best of our abilities, we have confirmed every detail
	with the electrical code, but we don't quote sections
	simply to keep this thing readable.  If you think we're wrong,
	we invite you to correct us, but please - quote references!

	The NEC and the CEC do not, in and of themselves, have the
	force of law.  Many municipalities adopt it en toto.  Others,
	however, do not.  Check your with your local building
	department (and <provincial> Hydro Inspection Offices in
	Canada) to find out what applies in your area.  Also,
	your local electrical utility may also have special requirements
	for electrical service installation.  Bear in mind, too, that
	we say here applies primarily to ordinary single-family
	residences.  Multi-family dwellings, mobile homes, commercial
	establishments, etc., are sometimes governed by different
	rules.

	Also note that, contrary to popular belief in the U.S. (and in
	some parts of Canada), Canada is not a wholly-owned subsidiary
	of the U.S.  Consequently, the NEC does not apply in Canada.
	Lots of things are the same, including voltages, line
	frequencies, and the laws of physics.  But there are a number
	of crucial differences in the regulations.  Where we can, we've
	noted them, flagging the relevant passages with ``NEC'' or
	``CEC''.

	Remember that the CEC and NEC are minimal standards.  It is often
	smart to go beyond their minimal requirements.

Subject: What is the NEC?  Where can I get a copy?

	The NEC is a model electrical code devised and published by the
	National Fire Protection Association, an insurance industry group.
	It's revised every three years.  The 1993 version has been released.
	You can buy a copy at a decent bookstore, or by calling them directly
	at 800-344-3555.  The code exists in several versions.  There's the
	full text, which is fairly incomprehensible.  There's an abridged
	edition, which has only the sections likely to apply to most houses.
	And there's the NEC Handbook, which contains the ``authorized
	commentary'' on the code, as well as the full text.  That's the
	recommended version.  Unfortunately, there's no handbook for
	the abridged edition.  And the full handbook is expensive --
	US$65 plus shipping and handling.

Subject: What is the CEC?  Where can I get a copy?

	The Canadian Standards Association is an organization made up
	of various government agencies, power utilities, insurance
	companies, electrical manufacturers and other organizations.
	The CSA publishes CSA Standard C22.1 which is updated every two
	or three years.  Each province adopts, with some amendments,
	this standard and publishes a province-specific code book.
	Since each province publishes its own slightly modified
	standard, it would be somewhat confusing to obtain the CSA
	standard itself.  In this FAQ, "CEC" really means the
	appropriate provincial standard.  In particular, this FAQ is
	derived from the Ontario Hydro Electrical Safety Code, 20th
	edition (1990).  Which is in turn based on CSA C22.1-1990 (16th
	edition).  While differences exist between the provinces, an
	attempt has been made to avoid specific-to-Ontario detail.

	The appropriate provincial code can be obtained from electrical
	inspection offices of your provincial power authority.  In
	Ontario, it's Ontario Hydro.  The Ontario Hydro book isn't
	overly fat.  It's about C$25, and includes mailed updates.  I
	hear that these standards are somewhat easier to read than the
	equivalent NEC publications.

	Don't bother asking in Quebec - DIY wiring is banned throughout
	the province.

Subject: Can I do my own wiring?  Extra pointers?

	In most places, homeowners are allowed to do their own wiring.
	In some, they're not.  Check with your local electrical
	inspector.  Most places won't permit you to do wiring on other's
	homes for money without a license.  Nor are you permitted to do
	wiring in "commercial" buildings.  Multiple dwellings (eg: duplexes)
	are usually considered "semi-commercial" or "commercial".  However,
	many jurisdictions will permit you to work on semi-commercial
	wiring if you're supervised by a licensed electrician - if you can
	find one willing to supervise.

	If you do your own wiring, an important point:

	Do it NEAT and WELL!  What you really want to aim for is a better
	job than an electrician will do.  After all, it's your own home,
	and it's you or your family that might get killed if you make
	a mistake.  An electrician has time pressures, has the skills
	and knows the tricks of the trade to do a fast, safe job.
	In this FAQ we've consciously given a few recommendations that
	are in excess of code, because we feel that it's reasonable,
	and will impress the inspector.

	The inspector will know that you're an amateur.  You have to
	earn his trust.  The best way of doing this is to spend your
	time doing as neat a job as possible.  Don't cut corners.
	Exceed specifications.  Otherwise, the inspector may get extremely
	picky and fault you on the slightest transgressions.

	Don't try to hide anything from the inspector.

	Use the proper tools.  Ie: don't use a bread knife to strip
	wires, or twist wires with your fingers.  The inspector
	won't like it, and the results won't be that safe.  And it
	takes longer.  And you're more likely to stick a hunk of
	12ga wire through your hand that way.

	Don't handle house wire when it's very cold (eg: below -10C
	or 16F).  Thermoplastic house wire, particularly older types
	become very brittle.

Subject: What do I need in the way of tools?

	First, there's the obvious -- a hammer, a drill, a few
	screwdrivers, both straight and Phillips-head.  If you're 
	lucky enough to live in Canada (or find a source of CSA-approved
	devices) you need Robertson ("square recess") screwdrivers
	(#1 and #2) instead of phillips.

	For drilling a few holes, a 3/4" or 1" spade bit and 1/4" or
	3/8" electric drill will do.  If you're doing a lot, or
	are working with elderly lumber, we recommend a 1/2" drill
	(right-angle drills are wonderful.  Can be rented) and
	3/4" or 1" screw-point auger drill bits.  These bits pull
	you through, so they're much faster and less fatiguing, even
	in 90 year old hardwood timbers.

	Screw-driver bits are useful for drills, expecially if you
	install your electrical boxes using screws (drywall screws
	work well).
	
	For stripping wire, use a real wire stripper, not a knife or
	ordinary wire cutters.  Don't buy the $3 K-mart "combo stripper,
	crimper and bottle opener" types.  You should expect to pay
	$15 to $20 for a good "plier-type" pair.  It will have sized
	stripping holes, and won't nick or grab the wire - it should
	be easy to strip wire with it.  One model has a small hole in the
	blade for forming exact wire loops for screw terminals.  There
	are fancier types (autostrip/cut), but they generally aren't
	necessary, and pros usually don't use them.

	A pair of diagonal side cutter pliers are useful for clipping ends
	in constricted places.  Don't use these for stripping wire.

	You will need linesman pliers for twisting wires for wire nuts.

	You should have a pair of needle-nose pliers for fiddling
	inside boxes and closing loops, but it's better to form wire
	loops with a "loop former hole" on your wire stripper - more
	accurate.

	If you're using non-metallic cable, get a cable stripper for
	removing the sheath.  Or, do what some pros do, they nick the
	end of the sheath, grab the ground wire with a pair of pliers,
	and simply rip the sheath back using the ground wire as a
	"zipper", and cut the sheath off.  You shouldn't try to strip
	the sheath with a knife point, because it's too easy to
	slash the insulation on the conductors.  Apparently Stanley
	utility knives fitted with linoleum cutters (hooked blades)
	can be used to strip sheath, but there is still the possibility
	that you'll gouge the conductors.

	For any substantial amount of work with armored cable, it's well
	worth your while to invest in a rotary cable splitter (~US$ 18).
	Hack saws are tricky to use without cutting into the wire
	or the insulation.

	Three-prong outlet testers are a quick check for properly-wired
	outlets.  About $6.  Multimeters tell you more, but are a lot more
	expensive, and probably not worth it for most people.  A simple
	voltage sensor, which can detect potential through an insulated
	wire not supplying any devices, is extremely helpful; they cost
	about US$ 10 at Radio Shack.

	You should have a voltage detector - to check that the wires are
	dead before doing work on them.  Neon-bulb version are cheap ($2-3)
	and work well.  If you get more serious, a "audible alarm" type is
	good for tracing circuits without a helper.  (Though I've been known
	to lock the drill on, and hit breakers until the scream stops ;-)

	For running wires through existing walls, you need fish tape.
	Often, two tapes are needed, though sometimes, a bent hanger or
	a length of thin chain will suffice.  Fish tapes can be rented.

	Electrical tape.  Lots of it ;-)  Seriously, a good and competent
	wiring job will need very little tape.  The tape is useful for
	wrapping dicy insulation in repair work.  Another use is to wrap 
	around the body of outlets and switches to cover the termination
	screws - I don't do this, but drywall contractors prefer it (to
	prevent explosions when the drywall knife collides with a live outlet
	that has no cover plate).

Subject: What is UL listing?

	The UL stands for "Underwriters Laboratory".  It used to be
	an Insurance Industry organization, but now it is independent
	and non-profit.  It tests electrical components and equipment
	for potential hazards.  When something is UL-listed, that means
	that the UL has tested the device, and it meets their requirements
	for safety - ie: fire or shock hazard.  It doesn't necessarily
	mean that the device actually does what it's supposed to, just
	that it probably won't kill you.

	The UL does not have power of law in the U.S. -- you are
	permitted to buy and install non-UL-listed devices.  However,
	insurance policies sometimes have clauses in them that will
	limit their liability in case of a claim made in response to
	the failure of a non-UL-listed device.  Furthermore, in
	many situations the NEC will require that a wiring component
	used for a specific purpose is UL-listed for that purpose.
	Indirectly, this means that certain parts of your wiring
	must be UL-listed before an inspector will approve it and/or
	occupancy permits issued.
	
Subject: What is CSA approval?

	Every electrical device or component must be certified by the
	Canadian Standards Association before it can be sold in
	Canada.  Implicit in this is that all wiring must be done
	with CSA-approved materials.  They perform testing similar to
	the UL (a bit more stringent), except that CSA approval is
	required by law.

	Again, like the UL, if a fire was caused by non-CSA-approved
	equipment, your insurance company may not have to pay the
	claim.

	In Canada, there is a branch organization of the UL, called ULC
	(UL of Canada).  ULC does not have power of law, and seems to
	be more a liason group between the CSA and insurance
	companies.

Subject: Are there any cheaper, easier to read books on wiring?

	USA: The following three books were suggested by our readers

	    Residential Wiring
	    by Jeff Markell,
	    Craftsman Books,
	    Carlsbad CA for $18.25. ISBN 0-934041-19-9.

	    Practical Electrical Wiring
	    Residential, Farm and Industrial,  Based on the National
	    Electrical Code    ANSI/NFPA 70
	    Herbert P. Richter and W. Creighton Schwan
	    McGraw-Hill Book Co.

	    Wiring Simplified
	    H. P. Richter and W. C. Schwan
	    Park Publishing Co.
	
	Try to make sure that the book is based on the latest NEC
	revision.  Which is currently 1990.

	Canada: P.S. Knight authors and publishes a book called
	"Electrical Code Simplified".  There appears to be a version
	published specific to each province, and is very tied into the
	appropriate provincial code.  It focuses on residential wiring,
	and is indispensible for Canadian DIY'ers.  It is better to get
	this book than the CEC unless you do a lot of wiring (or answer
	questions on the net ;-).

	It is updated each time the provincial codes are.  This book is
	available at all DIY and hardware stores for less than C$10.

Subject: Inspections how and what?  Why should I get my wiring inspected?

	Most jurisdictions require that you obtain a permit and
	inspections of any wiring that is done.  Amongst other more
	mundane bureaucratic reasons (like insurance companies not
	liking to have to pay claims), a permit and inspections
	provides some assurance that you, your family, your neighbors
	or subsequent owners of your home don't get killed or lose
	their homes one night due to a sloppy wiring job.

	Most jurisdictions have the power to order you to vacate your
	home, or order you to tear out any wiring done without a
	permit.  California, for instance, is particularly nasty about
	this.

	If fire starts in your home, and un-inspected wiring is at
	fault, insurance companies will often refuse to pay the damage
	claims.

	In general, the process goes like this:
		- you apply to your local inspections office or building
		  department for a permit.  You should have a sketch or
		  detailed drawing of what you plan on doing.  This is
		  a good time to ask questions on any things you're not
		  sure of.  If you're doing major work, they may impose
		  special conditions on you, require loading
		  calculations and ask other questions.  At this point
		  they will tell you which inspections you will need.
		- If you're installing a main panel, you will need to
		  have the panel and service connections inspected
		  before your power utility will provide a connection.
		  This is sometimes done by the local power authority
		  rather than the usual inspectors.
		- After installing the boxes and wiring, but before
		  the insulation/walls go up, you will need a
		  "rough-in" inspection.
		- After the walls are up, and the wiring is complete,
		  you will need a "final inspection".

Subject: My house doesn't meet some of these rules and regulations.
	Do I have to upgrade?

	In general, there is no requirement to upgrade older dwellings,
	though there are some exceptions (ie: smoke detectors in some
	cases).  However, any new work must be done according to the
	latest electrical code.  Also, if you do ``major'' work, you
	may be required to upgrade certain existing portions or all
	of your system.  Check with your local electrical inspector.

Subject: A word on voltages: 110/115/117/120/125/220/240

	One thing where things might get a bit confusing is the
	different numbers people bandy about for the voltage of
	a circuit.  One person might talk about 110V, another 117V
	or another 120V.  These are all, in fact, exactly the same
	thing...  In North America the utility companies are required
	to supply a split-phase 240 volt (+-5%) feed to your house.
	This works out as two 120V +- 5% legs.  Additionally, since there
	are resistive voltage drops in the house wiring, it's not
	unreasonable to find 120V has dropped to 110V or 240V has dropped
	to 220V by the time the power reaches a wall outlet.  Especially
	at the end of an extension cord or long circuit run.  For a number
	of reasons, some historical, some simple personal orneryness,
	different people choose call them by slightly different numbers.
	This FAQ has chosen to be consistent with calling them "110V" and
	"220V", except when actually saying what the measured voltage will
	be.  Confusing?  A bit.  Just ignore it.

	One thing that might make this a little more understandable
	is that the nameplates on equipment ofen show the lower (ie: 110V
	instead of 120V) value.  What this implies is that the device
	is designed to operate properly when the voltage drops that
	low.

	208V is *not* the same as 240V.  208V is the voltage between
	phases of a 3-phase "Y" circuit that is 120V from neutral to any
	hot.   480V is the voltage between phases of a 3-phase "Y"
	circuit that's 277V from hot to neutral.

	In keeping with 110V versus 120V strangeness, motors intended
	to run on 480V three phase are often labelled as 440V...

Subject: What does an electrical service look like?

	There are logically four wires involved with supplying the
	main panel with power.  Three of them will come from the utility
	pole, and a fourth (bare) wire comes from elsewhere.

 	The bare wire is connected to one or more long metal bars pounded
 	into the ground, or to a wire buried in the foundation, or sometimes
 	to the water supply pipe (has to be metal, continuous to where
	the main water pipe entering the house.  Watch out for galvanic
	action conductivity "breaks" (often between copper and iron pipe)).
	This is the "grounding conductor".  It is there to make sure that
	the third prong on your outlets is connected to ground.  This wire
	normally carries no current.

	One of the other wires will be white (or black with white or
	yellow stripes, or sometimes simply black).  It is the neutral wire.
	It is connected to the "centre tap" (CEC; "center tap" in the
	NEC) of the distribution transformer supplying the power.  It
	is connected to the grounding conductor in only one place (often
	inside the panel).  The neutral and ground should not be connected
	anywhere else.  Otherwise, weird and/or dangerous things may happen.

	Furthermore, there should only be one grounding system in
	a home.  Some codes require more than one grounding electrode.
	These will be connected together, or connected to the neutral
	at a common point - still one grounding system.  Adding additional
	grounding electrodes connected to other portions of the house
	wiring is unsafe and contrary to code.

	If you add a subpanel, the ground and neutral are usually
	brought as separate conductors from the main panel, and are
	not connected together in the subpanel (ie: still only one
	neutral-ground connection).  However, in some situations 
	(certain categories of separate buildings) you actually do
	have to provide a second grounding electrode - consult your
	inspector.

	The other two wires will usually be black, and are the "hot"
	wires.  They are attached to the distribution transformer as
	well.

	The two black wires are 180 degrees out of phase with each
	other.  This means if you connect something to both hot wires,
	the voltage will be 220 volts.  If you connect something to the
	white and either of the two blacks you will get 110V.

	Some panels seem to only have three wires coming into them.
	This is either because the neutral and ground are connected
	together at a different point (eg: the meter or pole) and one
	wire is doing dual-duty as both neutral and ground, or in some
	rare occasions, the service has only one hot wire (110V only
	service).

Subject: What is a circuit?

	Inside the panel, connections are made to the incoming wires.
	These connections are then used to supply power to selected
	portions of the home.  There are three different combinations:
		1) one hot, one neutral, and ground: 110V circuit.
		2) two hots, no neutral, and ground: 220V circuit.
		3) two hots, neutral, and ground: 220V circuit + neutral,
		   and/or two 110V circuits with a common neutral.

	(1) is used for most circuits supplying receptacles and
	lighting within your house.  (3) is usually used for supplying
	power to major appliances such as stoves, and dryers - they
	often have need for both 220V and 110V, or for bringing several
	circuits from the panel box to a distribution point.  (2) is
	usually for special 220V motor circuits, electric heaters, or
	air conditioners.

	[Note: In the US, the NEC frequently permits a circuit similar
	to (2) be used for stoves and dryers - namely, that there
	are two hot wires, and a wire that does dual duty as neutral
	and ground, and is connected to the frame as well as providing
	the neutral for 110V purposes - three prong plugs instead
	of four (*only* for stoves/dryers connected to the main panel.
	When connected to most sub-panels, 4 prong plugs and receptacles
	are required).  In our not-so-humble opinion this is crazy, but
	the NFPA claims that this practice was re-evaluated for the 1992 NEC,
	and found to be safe.  Check your local codes, or inquire as to
	local practice -- there are restrictions on when this is
	permissible.]

	(1) is usually wired with three conductor wire: black for hot,
	white for neutral, and bare for grounding.

	(2) and (3) have one hot wire coloured red, the other black, a
	bare wire for grounding, and in (3) a white wire for neutral.

	You will sometimes see (2) wired with just a black, white and ground
	wire.  Since the white is "hot" in this case, both the NEC and CEC
	requires that the white wire be "permanently marked" at the ends
	to indicate that it is a live wire.  Usually done with paint, nail
	polish or sometimes electrical tape.

	Each circuit is attached to the main wires coming into the
	panel through a circuit breaker or fuse.

	There are, in a few locales, circuits that look like (1), (2)
	or (3) except that they have two bare ground wires.  Some places
	require this for hot tubs and the like (one ground is "frame ground",
	the other attaches to the motor).  This may or may not be an
	alternative to GFCI protection.

Subject: "grounding" versus "grounded" versus "neutral".

	According to the terminology in the CEC and NEC, the
	"grounding" conductor is for the safety ground, i.e., the green
	or bare wire.  The word "neutral" is reserved for the white when
	you have a circuit with more than one "hot" wire.  Since the white
	wire is connected to neutral and the grounding conductor inside the
	panel, the proper term is "grounded conductor".  However, the
	potential confusion between "grounded conductor" and "grounding
	conductor" can lead to potentially lethal mistakes - you should
	never use the bare wire as a "grounded conductor" or white wire
	as the "grounding conductor", even though they are connected
	together in the panel.

	[But not in subpanels - subpanels are fed neutral and ground
	separately from the main panel.  Usually.]

	In the trade, and in common usage, the word "neutral" is used
	for "grounded conductor".  This FAQ uses "neutral" simply to
	avoid potential confusion.  We recommend that you use "neutral"
	too.  Thus the white wire is always (except in some light
	switch applications) neutral.  Not ground.

Subject: What does a fuse or breaker do?  What are the differences?

	Fuses and circuit breakers are designed to interrupt the power
	to a circuit when the current flow exceeds safe levels.  For
	example, if your toaster shorts out, a fuse or breaker should
	"trip", protecting the wiring in the walls from melting.  As
	such, fuses and breakers are primarily intended to protect the
	wiring -- UL or CSA approval supposedly indicates that the
	equipment itself won't cause a fire.

	Fuses contain a narrow strip of metal which is designed to melt
	(safely) when the current exceeds the rated value, thereby
	interrupting the power to the circuit.  Fuses trip relatively
	fast.  Which can sometimes be a problem with motors which have
	large startup current surges.  For motor circuits, you can use
	a "time-delay" fuse (one brand is "fusetron") which will avoid
	tripping on momentary overloads.  A fusetron looks like a
	spring-loaded fuse.  A fuse can only trip once, then it must be
	replaced.

	Breakers are fairly complicated mechanical devices.  They
	usually consist of one spring loaded contact which is latched
	into position against another contact.  When the current flow
	through the device exceeds the rated value, a bimetallic strip
	heats up and bends.  By bending it "trips" the latch, and the
	spring pulls the contacts apart.  Circuit breakers behave
	similarly to fusetrons - that is, they tend to take longer to
	trip at moderate overloads than ordinary fuses.  With high
	overloads, they trip quickly.  Breakers can be reset a finite
	number of times - each time they trip, or are thrown
	when the circuit is in use, some arcing takes place, which
	damages the contacts.  Thus, breakers should not be used in
	place of switches unless they are specially listed for the
	purpose.

	Neither fuses nor breakers "limit" the current per se.  A dead
	short on a circuit can cause hundreds or sometimes even
	thousands of amperes to flow for a short period of time, which
	can often cause severe damage.

Subject: Breakers?  Can't I use fuses?

	Statistics show that fuse panels have a significantly higher
	risk of causing a fire than breaker panels.  This is usually
	due to the fuse being loosely screwed in, or the contacts
	corroding and heating up over time, or the wrong size fuse
	being installed, or the proverbial "replace the fuse with a
	penny" trick.

	Since breakers are more permanently installed, and have better
	connection mechanisms, the risk of fire is considerably less.

	Fuses are prone to explode under extremely high overload.  When
	a fuse explodes, the metallic vapor cloud becomes a conducting
	path.  Result? from complete meltdown of the electrical panel,
	melted service wiring, through fires in the electrical
	distribution transformer and having your house burn down.
	Breakers don't do this.

	Many jurisdictions, particularly in Canada, no longer permit
	fuse panels in new installations.  The NEC does permit new
	fuse panels in some rare circumstances (requiring the special
	inserts to "key" the fuseholder to specific size fuses)

	Some devices, notably certain large air conditioners, require fuse
	protection in addition to the breaker at the panel.  The fuse
	is there to protect the motor windings from overload.  Check the
	labeling on the unit.  This is usually only on large permanently
	installed motors.  The installation instructions will tell you
	if you need one.

Subject: What size wire should I use?

	For a 20 amp circuit, use 12 gauge wire.  For a 15 amp circuit,
	you can use 14 gauge wire (in most locales).  For a long run,
	though, you should use the next larger size wire, to avoid
	voltage drops.  12 gauge is only slightly more expensive than
	14 gauge, though it's stiffer and harder to work with.

	Here's a quick table for normal situations.  Go up a size for
	more than 100 foot runs, when the cable is in conduit, or
	ganged with other wires in a place where they can't dissipate
	heat easily:

		Gauge		Amps
		14		15
		12		20
		10		30
		8		40
		6		65
	
	We don't list bigger sizes because it starts getting very dependent
	on the application and precise wire type.

Subject: Where do these numbers come from?

	There are two considerations, voltage drop and heat buildup.
	The smaller the wire is, the higher the resistance is.  When
	the resistance is higher, the wire heats up more, and there is
	more voltage drop in the wiring.  The former is why you need
	higher-temperature insulation and/or bigger wires for use in
	conduit; the latter is why you should use larger wire for long
	runs.

	Neither effect is very significant over very short distances.
	There are some very specific exceptions, where use of smaller
	wire is allowed.  The obvious one is the line cord on most
	lamps.  Don't try this unless you're certain that your use fits
	one of those exceptions; you can never go wrong by using larger
	wire.

Subject: What does "14-2" mean?

	This is used to describe the size and quantity of conductors
	in a cable.  The first number specifies the gauge.  The second
	the number of current carrying conductors in the wire - but
	remember there's usually an extra ground wire.  "14-2" means
	14 gauge, two insulated current carrying wires, plus bare ground.

	-2 wire usually has a black, white and bare ground wire.  Sometimes
	the white is red instead for 220V circuits without neutral.  In
	the latter case, the sheath is usually red too.

	-3 wire usually has a black, red, white and bare ground wire.
	Usually carrying 220V with neutral.

Subject: What is a "wirenut"/"marrette"/"marr connector"?  How are they
	used?

	A wire nut is a cone shaped threaded plastic thingummy that's used
	to connect wires together.  "Marrette" or "Marr connector"
	are trade names.  You'll usually use a lot of them in DIY wiring.

	In essence, you strip the end of the wires about an inch, twist them
	together, then twist the wirenut on.

	Though some wirenuts advertise that you don't need to twist the
	wire, do it anyways - it's more mechanically and electrically
	secure.

	There are many different sizes of wire nut.  You should check
	that the wire nut you're using is the correct size for the
	quantity and sizes of wire you're connecting together.

	Don't just gimble the wires together with a pair of pliers or
	your fingers.  Use a pair of blunt nose ("linesman") pliers,
	and carefully twist the wires tightly and neatly.  Sometimes
	it's a good idea to trim the resulting end to make sure it
	goes in the wirenut properly.

	Some people wrap the "open" end of the wirenut with electrical
	tape.  This is probably not a good idea - the inspector may
	tear it off during an inspection.  It's usually done because
	a bit of bare wire is exposed outside the wire nut - instead
	of taping it, the connection should be redone.

Subject: What is a GFI/GFCI?

	A GFCI is a ``ground-fault circuit interrupter''.  It measures
	the current current flowing through the hot wire and the
	neutral wire.  If they differ by more than a few milliamps, the
	presumption is that current is leaking to ground via some other
	path.  This may be because of a short circuit to the chassis of
	an appliance, or to the ground lead, or through a person.  Any
	of these situations is hazardous, so the GFCI trips, breaking
	the circuit.

	GFCIs do not protect against all kinds of electric shocks.  If,
	for example, you simultaneously touched the hot and neutral
	leads of a circuit, and no part of you was grounded, a GFCI
	wouldn't help.  All of the current that passed from the hot
	lead into you would return via the neutral lead, keeping the
	GFCI happy.

	The two pairs of connections on a GFCI outlet are not symmetric.
	One is labeled LOAD; the other, LINE.  The incoming power feed
	*must* be connected to the LINE side, or the outlet will not be
	protected.  The LOAD side can be used to protect all devices
	downstream from it.  Thus, a whole string of outlets can be
	covered by a single GFCI outlet.

Subject: Where should GFCIs be used?

	The NEC mandates GFCIs for 110V, 15A or 20A single phase
	outlets, in bathrooms, kitchens within 6' of the sink, garages,
	unfinished basements or crawl spaces, outdoors, near a pool, or
	just about anywhere else where you're likely to encounter water
	or dampness.  There are exceptions for inaccessible outlets,
	those dedicated to appliances ``occupying fixed space'',
	typically refrigerators and freezers, and for sump pumps and
	laundry appliances.

	The CEC does not mandate as many GFCIs.  In particular, there
	is no requirement to protect kitchen outlets, or most garage or
	basement outlets.  Basement outlets must be protected if you
	have a dirt floor, garage outlets if they're near the door to
	outside.  Bathrooms and most exterior outlets must have GFCIs.

	Even if you are not required to have GFCI protection, you may
	want to consider installing it anyway.  Unless you need a GFCI
	breaker (see below), the cost is low.  In the U.S., GFCI
	outlets can cost as little as US$8.  (Costs are a bit higher in
	Canada:  C$12.)  Evaluate your own risk factors.  Does your
	finished basement ever get wet?  Do you have small children?
	Do you use your garage outlets to power outdoor tools?  Does
	water or melted snow ever puddle inside your garage?

Subject: Where shouldn't I use a GFCI?

	GFCIs are generally not used on circuits that (a) don't pose a
	safety risk, and (b) are used to power equipment that must run
	unattended for long periods of time.  Refrigerators, freezers,
	and sump pumps are good examples.  The rationale is that GFCIs
	are sometimes prone to nuisance trips.  Some people claim that
	the inductive delay in motor windings can cause a momentary
	current imbalance, tripping the GFCI.  Note, though, that most
	GFCI trips are real; if you're getting a lot of trips for no
	apparent reason, you'd be well-advised to check your wiring
	before deciding that the GFCI is broken or useless.

Subject: What is the difference between a GFCI outlet and a GFCI breaker?

	For most situations, you can use either a GFCI outlet as the
	first device on the circuit, or you can install a breaker with
	a built-in GFCI.  The former is generally preferred, since GFCI
	breakers are quite expensive.  For example, an ordinary GE
	breaker costs ~US$5; the GFCI model costs ~US$35.  There is one
	major exception:  if you need to protect a ``multi-wire branch
	circuit'' (two or more circuits sharing a common neutral wire),
	such as a Canadian-style kitchen circuit, you'll need a
	multi-pole GFCI breaker.  Unfortunately, these are expensive;
	the cost can range into the hundreds of dollars, depending on
	what brand of panel box you have.  But if you must protect such
	a circuit (say, for a pool heater), you have no choice.

	One more caveat -- GFCI outlets are bulky.  You may want to use
	an oversize box when installing them.  On second thought, use
	large (actually deep) boxes everywhere.  You'll thank yourself for it.

	Incidentally, if you're installing a GFCI to ensure that one
	specific outlet is protected (such as a bathroom), you don't
	really have to go to all of the trouble to find the first
	outlet in the circuit, you could simply find the first outlet
	in the bathroom, and not GFCI anything upstream of it.  But
	protecting the whole circuit is preferred.

	When you install a GFCI, it's a good idea to use the little
	"ground fault protected" stickers that come with it and mark
	the outlets downstream of the GFCI.  You can figure out which
	outlets are "downstream", simply by tripping the GFCI with the
	test button and see which outlets are dead.

Subject: What's the purpose of the ground prong on an outlet, then?

	Apart from their use in electronics, which we won't comment on,
	and for certain fluorescent lights (they won't turn on without
	a good ground connection), they're intended to guard against
	insulation failures within the device.  Generally, the case of
	the appliance is connected to the ground lead.  If there's an
	insulation failure that shorts the hot lead to the case, the
	ground lead conducts the electricity away safely (and possibly
	trips the circuit breaker in the process).  If the case is not
	grounded and such a short occurs, the case is live -- and if
	you touch it while you're grounded, you'll get zapped.  Of
	course, if the circuit is GFCI-protected, it will be a very
	tiny zap -- which is why you can use GFCIs to replace
	ungrounded outlets (both NEC and CEC).

	There are some appliances that should *never* be grounded.  In
	particular, that applies to toasters and anything else with
	exposed conductors.  Consider:  if you touch the heating
	electrode in a toaster, and you're not grounded, nothing will
	happen.  If you're slightly grounded, you'll get a small shock;
	the resistance will be too high.  But if the case were
	grounded, and you were holding it, you'd be the perfect path to
	ground...

Subject: Why is one prong wider than the other?  Polarization

	Nowadays, many two-prong devices have one prong wider than the
	other.  This is so that the device could rely (not guaranteed!)
	on one specific wire being neutral, and the other hot.
	This is particularly advantageous in light fixtures, where the
	the shell should neutral (safety), or other devices which want to
	have an approximate ground reference (ie: some radios).

	Most 2-prong extension cords have wide prongs too.

	This requires that you wire your outlets and plugs the right
	way around.  You want the wide prong to be neutral, and the
	narrow one hot.  Most outlets have a darker metal for the
	hot screw, and lighter coloured screw for the neutral.
	If not, you can usually figure out which is which by which
	prong the terminating screw connects to.

Subject: What kind of outlets do I need in a kitchen?

	The NEC requires at least two 20 amp ``small appliance
	circuits'' for kitchens.  The CEC requires split-duplex
	receptacles.  Outlets must be installed such that no point is more
	than 24" (NEC) (900 mm CEC) from an outlet.  Every counter wider
	than 12" (NEC) or 300 mm (CEC) must have at least one outlet.
	The circuit these outlets are on may not feed any outlets except
	in the kitchen, pantry, or dining room.  Furthermore, these circuits
	are in addition to any required for refrigerators, stoves, microwaves,
	lighting, etc.  Non-dedicated outlets within 6' of a sink *must* be
	protected by a GFCI (NEC only).

	Split duplex receptacles are fed with a 220V circuit.  The tab
	is broken on the hot side of the outlet, and one hot goes to
	the upper outlet, and the other hot goes to the lower outlet.
	The neutral connects to both outlets through one screw.  When
	"carrying through" to another outlet, the neutral must be
	pigtailed, such that removing the outlet, or having the neutral
	connection fall off doesn't cause the neutral to disconnect
	from downstream outlets.

Subject: Where must outlets and switches be in bathrooms?

	There must be at least one outlet in each bathroom, adjacent to
	the sink, in addition to any outlet that may be incorporated in
	the light fixture.  All such outlets *must* be GFCI-protected.

Subject: What is Romex/NM/NMD?  What is BX?  When should I use each?

	Romex is a brand name for a type of plastic insulated wire.
	Sometimes called non-metallic sheath.  The formal name is NM.
	This is suitable for use in dry, protected areas (ie: inside
	stud walls, on the sides of joists etc.), that are not subject
	to mechanical damage or excessive heat.  Most newer homes are
	wired almost exclusively with NM wire.  There are several
	different categories of NM cable.

	BX cable -- technically known as armored cable or "AC" has a
	flexible aluminum or steel sheath over the conductors and is
	fairly resistant to damage.

	TECK cable is AC with an additional external thermoplastic
	sheath.
	
	Protection for cable in concealed locations: where NM or AC cable
	is run through studs, joists or similar wooden members, the outer
	surface of the cable must be kept at least 32mm/1.25" (CEC & NEC)
	from the edges of the wooden members, or the cable should be protected
	from mechanical injury.  This latter protection can take the form of
	metal plates (such as spare outlet box ends) or conduit.

	[Note: inspector-permitted practise in Canada suggests that armored
	cable, or flexible conduit can be used as the mechanical protection,
	but this is technically illegal.]

	Additional protection recommendations (these are rules in the
	Canadian codes - they are reasonable answers to the vague
	references to "exposed to mechanical damage" in both the NEC
	and CEC):

	    - NM cable should be protected against mechanical damage
	      where it passes through floors or on the surface of walls
	      in exposed locations under 5 feet from the floor.
	      Ie: use AC instead, flexible conduit, wooden guards etc.
	    - Where cable is suspended, as in, connections to furnaces
	      or water heaters, the wire should be protected.  Canadian
	      practise is usually to install a junction or outlet
	      box on the wall, and use a short length of AC cable
	      or NM cable in flexible conduit to "jump" to the appliance.
	      Stapling NM to a piece of lumber is also sometimes used.
	    - Where NM cable is run in close proximity to heating
	      ducts or pipe, heat transfer should be minimized by
	      means of a 25mm/1" air space, or suitable insulation
	      material (a wad of fiberglass).
	    - NM cable shall be supported within 300mm/1' of every box
	      or fitting, and at intervals of no more than 1.5m/5'.
	      Holes in joists or studs are considered "supports".
	      Some slack in the cable should be provided adjacent to
	      each box.  [while fishing cable is technically in violation,
	      it is permitted where "proper" support is impractical]
	    - 2 conductor NM cable should never be stapled on edge.
	      [Knight also insists on only one cable per staple, referring
	      to the "workmanship" clause, but this seems more honoured
	      in the breach...]
	    - cable should never be buried in plaster, cement or
	      similar finish.
	    - cable should be protected where it runs behind baseboards.
	    - Cable may not be run on the upper edge of ceiling joists
	      or the lower edges of rafters where the headroom is more
	      than 1m (39").

	Whenever BX cable is terminated at a box with a clamp, small
	plastic bushings must be inserted in the end of the cable to
	prevent the clamps forcing the sharp ends of the armor through
	the insulation.

	BX is sometimes a good idea in a work shop unless covered by
	solid wall coverings.

	In places where damage is more likely (like on the back wall of
	a garage ;-), you may be required to use conduit, a
	UL- (or CSA-) approved metal pipe.  You use various types of
	fittings to join the pipe or provide entrance/exit for the
	wire.

	Service entrances frequently use a plastic conduit.

	In damp places (eg: buried wiring to outdoor lighting) you will
	need special wire (eg: CEC NMW90, NEC UF).  NMW90 looks like
	very heavy-duty NMD90.  You will usually need short lengths of
	conduit where the wire enters/exits the ground.  [See underground
	wiring section.]

 	Thermoplastic sheath wire (such as NM, NMW etc.) should not be
 	exposed to direct sunlight unless explicitly approved for that
 	purpose.

	Many electrical codes do not permit the routing of wire through
	furnace ducts, including cold air return plenums constructed
	by metal sheeting enclosing joist spaces.   The reason for this
	is that if there's a fire, the ducting will spread toxic gasses
	from burning insulation very rapidly through the building.
	Teflon insulated wire is permitted in plenums in many areas.
	
 	Canada appears to use similar wire designations to the US,
 	except that Canadian wire designations usually include the
 	temperature rating in Celsius.  Eg: "AC90" versus "AC".
	In the US, NM-B is 90 degrees celcius.

	NOTE: local codes vary.  This is one of the items that changes
	most often.  Eg: Chicago codes require conduit *everywhere*.
	There are very different requirements for mobile homes.
	Check your local codes, *especially* if you're doing anything
	that's the slightest out of the ordinary.

	Wire selection table (incomplete - the real tables are enormous,
	uncommon wire types or applications omitted)

	Condition			Type	CEC	NEC

	Exposed/Concealed dry		plastic	NMD90	NM
					armor	AC90	AC
						TECK90

	Exposed/Concealed damp		plastic	NMD90	NMC
					armor	ACWU90
						TECK90

	Exposed/Concealed wet		plastic	NMWU90
					armor	ACWU90
						TECK90
	
	Exposed to weather		plastic	NMWU
						TW etc.
					armor	TECK90
	
	Direct earth burial/		plastic	NMWU*	UF
	Service entrance			RWU
						TWU
					armor	RA90
						TECK90
						ACWU90
	[* NMWU not for service entrance]

Subject: Should I use plastic or metal boxes?

	The NEC permits use of plastic boxes with non-metallic cable
	only.  The reasoning is simple -- with armored cable, the box
	itself provides ground conductor continuity.  U.S. plastic
	boxes don't use metal cable clamps.

	The CEC is slightly different.  The CEC never permits cable
	armor as a grounding conductor.  However, you must still
	provide ground continuity for metallic sheath.  The CEC also
	requires grounding of any metal cable clamps on plastic boxes.

	The advantage of plastic boxes is comparatively minor even for
	non-metallic sheathed cable -- you can avoid making one ground
	connection and they sometimes cost a little less.  On the other
	hand, plastic boxes are more vulnerable to impacts.  For
	exposed or shop wiring, metal boxes are probably better.

Subject: Junction box positioning?

	A junction box is a box used only for connecting wires together.

	Junction boxes must be located in such a way that they're accessible
	later.  Ie: not buried under plaster.  Excessive use of junction
	boxes is often a sign of sloppy installation, and inspectors may
	get nasty.

Subject: Can I install a replacement light fixture?

	In general, one can replace fixtures freely, subject to a few
	caveats.  First, of course, one should check the amperage
	rating of the circuit.  If your heart is set on installing half
	a dozen 500 watt floodlights, you may need to run a new wire
	back to the panel box.  But there are some more subtle
	constraints as well.  For example, older house
	wiring doesn't have high-temperature insulation.  The excess
	heat generated by a ceiling-mounted lamp can and will cause the
	insulation to deteriorate and crack, with obvious bad results.
	Some newer fixtures are specifically marked for high
	temperature wire only.  (You may find, in fact, that your
	ceiling wiring already has this problem, in which case
	replacing any devices is a real adventure.)

	Other concerns include providing a suitable ground for some
	fluorescent fixtures, and making sure that the ceiling box and
	its mounting are strong enough to support the weight of a heavy
	chandelier or ceiling fan.  You may need to install a new box
	specifically listed for this purpose.  A 2x4 across the ceiling
	joists makes a good support.  Metal brackets are also available
	that can be fished into ceilings thru the junction box hole and
	mounted between the joists.

	There are special rules for recessed light fixtures such as
	"pot" lamps or heat lamps.  When these are installed in insulated
	ceilings, they can present a very substantial fire hazard.
	The CEC provides for the installation of pot lamps in insulated
	ceilings, provided that the fixture is boxed in a "coffin" (usually
	8'x16"x12" - made by making a pair of joists 12" high, and covering
	with plywood) that doesn't have any insulation.  (Yes, that's 8 *feet*
	long)

	NEC rules are somewhat less stringent.  They require at least 3"
	clearance between the fixture and any sort of thermal insulation.
	The rules also say that one should not obstruct free air movement,
	which means that a CEC-style ``coffin'' might be worthwhile.
	Presumably, that's up to the local inspector.  [The CEC doesn't
	actually mandate the coffin per-se, this seems to be an inspector
	requirement to make absolutely certain that the fixture can't get
	accidentally buried in insulation.  Ie: if you have insulation blown
	in later.]

	There are now fixtures that contain integral thermal cutouts and
	fairly large cases that can be buried directly in insulation.  They are
	usually limited to 75 watt bulbs, and are unfortunately, somewhat
	more expensive than the older types.  Before you use them, you should
	ensure that they have explicit UL or CSA approval for such uses.
	Follow the installation instructions carefully; the prescribed location
	for the sensor can vary.

	There does not yet appear to be a heat lamp fixture that is approved
	for use in insulation.  The "coffin" appears the only legal approach.

Subject: What does it mean when the lights brighten when a motor starts?

	This usually means that the neutral wire in the panel is
	loose.  Depending on the load balance, one hot wire may end up
	being more than 110V, and the other less than 110V, with
	respect to ground.  This is a very hazardous situation - it can
	destroy your electronic equipment, possibly start fires, and in
	some situations electrocute you (ie: some US jurisdictions
	require the stove frame connected to neutral).

	If this happens, contact your electrical authority immediately
	and have them come and check out the problem.

	Note: a brief (< 1 second) brightening is sometimes normal with
	lighting and motors on the same 220V with neutral circuit.  A
	loose main panel neutral will usually show increased brightness
	far longer than one second.  In case of doubt, get help.

Subject: What is 3 phase power?  Should I use it?  Can I get it in my house?

	Three phase power has three "hot" wires, 120 degrees out of
	phase with each other.  These are usually used for large motors
	because it is more "efficient", provides a bit more starting torque,
	and because the motors are simpler and hence cheaper.

	You're most likely to encounter a 3 phase circuit that shows
	110 volts between any hot and ground, and 208 volts between
	any two hots.  The latter shows the difference between a normal
	220V/110V common neutral circuit, which is 240 volts between the
	two hots.  There are 3 phase circuits with different voltages.

	Bringing in a 3 phase feed to your house is usually
	ridiculously expensive, or impossible.  If the equipment you
	want to run has a standard motor mount, it is *MUCH* cheaper to
	buy a new 110V or 220V motor for it.  In some cases it is
	possible to run 3 phase equipment on ordinary power if you have
	a "capacitor start" unit, or use a larger motor as a
	(auto-)generator.  These are tricky, but are a good solution if
	the motor is non-standard size, or too expensive or too big to
	replace.  The Taunton Press book ``The Small Shop'' has an
	article on how to do this if you must.

	Note that you lose any possible electrical efficiency by using
	such a converter.  The laws of thermodynamics guarantee that.

Subject: Is it better to run motors at 110 or 220?

	Theoretically, it doesn't make any difference.  However, there
	is a difference is the amount of power lost in the supply
	wiring.  All things being equal, a 220V motor will lose 4 times
	less power in the house wiring than a 110V motor.  This also
	means that the startup surge loss will be less, and the motor
	will get to speed quicker.  And in some circumstances, the
	smaller power loss will lead to longer motor life.

	This is usually irrelevant unless the supply wires are more
	than 50 feet long.

Subject: What is this nonsense about 3HP on 110V 15A circuits?

	It is a universal physical law that 1 HP is equal to 746
	watts.  Given heating loss, power factor and other inefficiencies,
	it is usually best to consider 1 HP is going to need 1000-1200
	watts.  A 110V 15A circuit can only deliver 1850 watts to a motor,
	so it cannot possibly be more than approximately 2 HP.  Given rational
	efficiency factors, 1.5HP is more like it.

	Some equipment manufacturers (Sears in particular, most router
	manufacturers in general ;-) advertise a HP rating that is far
	in excess of what is possible.  They are giving you a "stall
	horsepower" or similar.  That means the power is measured when
	the motor is just about to stop turning because of the load.
	What they don't mention is that if you kept it in that
	condition for more than a few seconds hopefully your breaker
	will trip, otherwise the motor will melt -- it's drawing far
	more current than it can continuously.

	When comparing motors, compare the continuous horsepower.  This
	should be on the motor nameplate.  If you can't find that figure,
	check the amperage rating, which is always present.

Subject: How do I convert two prong receptacles to three prong?

	Older homes frequently have two-prong receptacles instead
	of the more modern three.  These receptacles have no safety
	ground, and the cabling usually has no ground wire.  Neither
	the NEC or CEC permits installing new 2 prong receptacles anymore.

	There are several different approaches to solving this:
	    1) If the wiring is done through conduit or BX, and the
	       conduit is continuous back to the panel, you can connect
	       the third prong of a new receptacle to the receptacle
	       box.  NEC mainly - CEC frowns on this practise.
	    2) If there is a copper cold water pipe going nearby, and
	       it's continuous to the main house ground point, you can
	       run a conductor to it from the third prong.
	    3) Run a ground conductor back to the main panel.
	    4) Easiest: install a GFCI receptacle.  The ground lug
	       should not be connected to anything, but the GFCI
	       protection itself will serve instead.  The GFCI
	       will also protect downstream (possibly also two prong
	       outlets).  If you do this to protect downstream outlets,
	       the grounds must not be connected together.  Since it
	       wouldn't be connected to a real ground, a wiring fault
	       could energize the cases of 3 prong devices connected
	       to other outlets.  Be sure, though, that there aren't
	       indirect ground plug connections, such as via the sheath
	       on BX cable.

	The CEC permits you to replace a two prong receptacle with a three
	prong if you fill the U ground with a non-conducting goop.
	Like caulking compound.  This is not permitted in the NEC.

Subject: Are you sure about GFCIs and ungrounded outlets?
	Should the test button work?

	We're sure about what the NEC and CEC say.  Remember, though,
	that your local codes may vary.  As for the TEST button -- there's
	a resistor connecting the LOAD side of the hot wire to the LINE
	side of the neutral wire when you press the TEST button.  Current
	through this resistor shows up as an imbalance, and trips the GFCI.
	This is a simple, passive, and reliable test, and doesn't require
	a real ground to work.  If your GFCI does not trip when you press
	the TEST button, it is very probably defective or miswired.  Again:
	if the test button doesn't work, something's broken, and potentially
	dangerous.  The problem should be corrected immediately.

	The instructions that come with some GFCIs specify that the ground
	wire must be connected.  We do not know why they say this.  The
	causes may be as mundane as an old instruction sheet, or with the
	formalities of UL or CSA listing -- perhaps the device was never
	tested without the ground wire being connected.  On the other hand,
	UL or CSA approval should only have been granted if the device
	behaves properly in *all* listed applications, including ungrounded
	outlet replacement.  (One of us called Leviton; their GFCIs are
	labeled for installation on grounded circuits only.  The technician
	was surprised to see that; he agreed that the NEC does not require
	it, and promised to investigate.)

Subject: How should I wire my shop?

	As with any other kind of wiring, you need enough power for all
	devices that will be on simultaneously.  The code specifies
	that you should stay under 80% of the nominal capacity of the
	circuit.  For typical home shop use, this means one circuit for
	the major power tools, and possibly one for a dust collector or
	shop vac.  Use at least 12 gauge wire -- many power tools have
	big motors, with a big start-up surge.  If you can, use 20 amp
	breakers (NEC), though CEC requires standard 20A receptacles
	which means you'd have to "replug" all your equipment.  Lights
	should either be on a circuit of their own -- and not shared
	with circuits in the rest of the house -- or be on at least two
	separate circuits.  The idea is that you want to avoid a
	situation where a blade is still spinning at several thousand
	RPM, while you're groping in the dark for the OFF switch.

	Do install lots of outlets.  It's easier to install them in the
	beginning, when you don't have to cut into an existing cable.
	It's useful if at least two circuits are accessible at each
	point, so you can run a shop vac or a compressor at the same
	time as the tool you really want.  But use metal boxes and
	plates, and maybe even metal-sheathed cable; you may have
	objects flying around at high speeds if something goes a bit
	wrong.

	Note that some jurisdictions have a "no horizontal wiring"
	rule in workshops or other unfinished areas that are used
	for working.  What this means is that all wiring must be
	run along structural members.  Ie: stapled to studs.

	Other possible shop circuits include heater circuits, 220V
	circuits for some large tools, and air compressor circuits.
	Don't overload circuits, and don't use extension cords if you
	can help it, unless they're rated for high currents.  (A coiled
	extension cord is not as safe as a straight length of wire of
	the same gauge.  Also, the insulation won't withstand as much
	heat, and heat dissipation is the critical issue.)

	If your shop is located at some remove from your main panel,
	you should probably install a subpanel, and derive your shop
	wiring from it.  If you have young children, you may want to
	equip this panel with a cut-off switch, and possibly a lock.
	If you want to install individual switches to ``safe''
	particular circuits, make sure you get ones rated high enough.
	For example, ordinary light switches are not safely able to
	handle the start-up surge generated by a table saw.  Buy
	``horsepower-rated'' switches instead.

	Finally, note that most home shops are in garages or unfinished
	basements; hence the NEC requirements for GFCIs apply.  And
	even if you ``know'' that you'd never use one of your shop
	outlets to run a lawn mower, the next owner of your house might
	have a different idea.

	Note: Fine Woodworking magazine often carries articles on shop
	wiring.  April 1992 is one place to start.

Subject: Underground Wiring

	You will need to prepare a trench to specifications, use
	special wire, protect the wire with conduit or special plastic
	tubing and possibly lumber (don't use creosoted lumber, it rots
	thermoplastic insulation and acts as a catalyst in the corrosion
	of lead).  The transition from in-house to underground wire is
	generally via conduit.  All outdoor boxes must be specifically
	listed for the purpose, and contain the appropriate gaskets,
	fittings, etc.  If the location of the box is subject to immersion
	in water, a more serious style of water-proof box is needed.  And
	of course, don't forget the GFCIs.

	The required depths and other details vary from jurisdiction to
	jurisdiction, so we suggest you consult your inspector about
	your specific situation.

	A hint: buy a roll of bright yellow tape that says "buried power
	line" and bury it a few inches above where the wire has been placed.

Subject: Aluminum wiring

	During the 1970's, aluminum (instead of copper) wiring became
	quite popular and was extensively used.  Since that time,
	aluminum wiring has been implicated in a number of house fires,
	and most jurisdictions no longer permit it in new installations.
	We recommend, even if you're allowed to, that do not use it for new
	wiring.

	But don't panic if your house has aluminum wiring.  Aluminum
	wiring, when properly installed, can be just as safe as copper.
	Aluminum wiring is, however, very unforgiving of improper
	installation.  We will cover a bit of the theory behind potential
	problems, and what you can do to make your wiring safe.

	The main problem with aluminum wiring is a phenomenon known as
	"cold creep".  When aluminum wiring warms up, it expands.  When
	it cools down, it contracts.  Unlike copper, when aluminum goes
	through a number of warm/cool cycles it loses a bit of tightness each
	time.  To make the problem worse, aluminum oxidises, or corrodes
	when in contact with certain types of metal, so the resistance
	of the connection goes up.  Which causes it to heat up and corrode/
	oxidize still more.  Eventually the wire may start getting very hot,
	melt the insulation or fixture it's attached to, and possibly even
	cause a fire.

	Since people usually encounter aluminum wiring when they move
	into a house built during the 70's, we will cover basic points of
	safe aluminum wiring.  We suggest that, if you're considering purchasing
	a home with aluminum wiring, or have discovered it later, that you
	hire a licensed electrician or inspector to check over the wiring
	for the following things:

	    1) Fixtures (eg: outlets and switches) directly attached to
	       aluminum wiring should be rated for it.  The device will
	       be stamped with "Al/Cu" or "CO/ALR".  The latter supersedes
	       the former, but both are safe.   These fixtures are somewhat
	       more expensive than the ordinary ones.

	    2) Wires should be properly connected (at least 3/4 way around
	       the screw in a clockwise direction).  Connections should be
	       tight.  While repeated tightening of the screws can make the
	       problem worse, during the inspection it would pay off to snug
	       up each connection.

	       Note that aluminum wiring is still often used for the
	       main service entrance cable.  It should be inspected.

	    3) "push-in" terminals are an extreme hazard with aluminum wire.
	       Any connections using push-in terminals should be redone with
	       the proper screw connections immediately.

	    4) There should be no signs of overheating: darkened connections,
	       melted insulation, or "baked" fixtures.  Any such damage should
	       be repaired.
	    
	    5) Connections between aluminum and copper wire need to be
	       handled specially.  Current Canadian codes require that the
	       wire nut used must be specially marked for connecting
	       aluminum to copper.  The NEC requires that the wire be
	       connected together using special crimp devices, with an
	       anti-oxidant grease.  The tools and materials for the latter
	       are quite expensive - not practical to do it yourself unless
	       you can rent the tool.

	    6) Any non-rated receptacle can be connected to aluminum wiring
	       by means of a short copper "pigtail".  See (5) above.
	    
	    7) Shows reasonable workmanship: neat wiring, properly stripped
	       (not nicked) wire etc.
    
	If, when considering purchasing a home, an inspection of the wiring
	shows no problems or only one or two, we believe that you can consider
	the wiring safe.  If there are signs of problems in many places,
	we suggest you look elsewhere.  If the wrong receptacles are used,
	you can replace them with the proper type, or use pigtails - having
	this professionally done can range from $3 to $10 per receptacle/switch.
	You can do this yourself too.

Subject: I'm buying a house!  What should I do?

	Congratulations.  But...  It's generally a good idea to hire
	an inspector to look through the house for hidden gotchas.
	Not just for wiring, but plumbing and structural as well.  If an
	inspection of the wiring shows no problems or only one or two minor
	ones, we believe that you can consider the wiring safe (after any
	minor problems are fixed).  If there are signs of problems in many
	places, we suggest you look elsewhere.

	Here's some hints on what to look for:

	Obvious non-code wiring can include:

		- Zip cord wiring, either concealed or nailed to walls
		- Hot wiring on the identified (neutral) conductor without
		  proper marking.
		- Ungrounded grounding outlets (except when downstream of
		  a GFCI)
		- Splices hanging in mid-air (other than proper knob-and-tube)
		- Switched neutrals
		- Unsecured Romex swinging about like grapevines

	Certain wiring practises that are actually to code (or were at one
	time) sometimes reveal DIY wiring that may have hidden violations:

		- Switches that seem to control nothing (abandoned, perhaps
		   not properly terminated wiring)
		- A wall switch that shuts off a group of lights that are
		  separately controlled by other wall switches.  (except when
		  it's *really* convenient ;-)
		- Switches and outlets in bizarre locations
		- Great numbers of junction boxes without outlets or lamps
		- Junction boxes with great numbers of wires going into them
		- Wiring that passes through a closet instead of a wall or
		  ceiling
		- Backwrapped grounding wires

Subject: What is this weird stuff?  Old style wiring
	
	In the years since Edison "invented" electricity, several different
	wiring "styles" have come and gone.  When you buy an older home you
	may encounter some of this stuff.  This section describes the old 
	methods, and some of their idiosyncrasies.

	The oldest wiring system you're likely to encounter is called
	"knob and tube" (K&T).  It is made up of individual conductors with
	a cloth insulation.  The wires are run along side structural
	members (eg: joists or studs) using ceramic stand-offs (knobs).
	Wire is run through structural members using ceramic tubes.  Connections
	were made by twisting the wire together, soldering, and wrapping
	with tape.  Since the hot and neutral were run separately,
	the wiring tends to be rather confusing.  A neutral often runs
	down the centre of each room, with "taps" off to each fixture.
	The hot wire tended to run from one fixture to the next.  In some
	cases K&T isn't colour-coded, so the neutral is often the same
	colour as the hot wires.

	You'll see K&T in homes built as late as the 40's.

	Comments on K&T:

		- the people installing K&T were pretty paranoid about
		  electricity, so the workmanship tends to be pretty good.
		- The wire, insulation and insulators tend to stand up
		  very well.  Most K&T I've seen, for example, is in
		  quite good condition.
		- No grounding.  Grounding is usually difficult to install.
		- boxes are small.  Receptacle replacement (particularly with
		  GFCI) can be difficult.  No bushing on boxes either,
		  so wiring changes need special attention to box entry.
		- Sometimes the neutral isn't balanced very well between
		  separately hot circuits, so it is sometimes possible to
		  overload the neutral without exceeding the fusing on
		  any circuit.
		- Building code does not permit insulation in walls
		  that contain K&T.
		- Connection to existing K&T from new circuits can be
		  tricky.  Consult your inspector.
		- Modern wiring practise requires considerably more
		  outlets to be installed than K&T systems did.
	
	Since K&T tends to be in pretty decent condition it generally isn't
	necessary to replace it simply because it's K&T.  What you should
	watch out for is renovations that have interfered with it and
	be cautious about circuit loading.  In many cases it's perfectly
	reasonable to leave existing K&T alone, and add new fixtures on
	new circuits using modern techniques.
	
	After K&T, they invented multi-conductor cable.  The first type
	you will see is roughly a cloth and varnish insulation.  It looks
	much like the romex cable of the last decade or two.  This stuff was
	used in the 40's and 50's.  Again, no grounding conductor.
	It was installed much like modern wiring.  Its major drawback
	is that this type of insulation embrittles.  We've seen whole
	systems where the insulation would fracture and fall off at
	a touch.  BX cable of the same vintage has similar problems.

	This stuff is very fragile, and becomes rather hazardous if
	the wires become bare.  This wiring should be left untouched as
	much as possible - whenever an opportunity arises, replace it.
	A simple receptacle or switch replacement can turn into a several
	hour long frustrating fight with electrical tape or heat-shrink
	tubing.

	After this wiring technique, the more modern romex was invented.
	It's almost a asphalt impregnated cloth.  Often a bit sticky.
	This stuff stands up reasonably well and doesn't present a hazard
	and is reasonably easy to work with.  It does not need to be
	replaced - it should be considered as safe as the "modern" stuff -
	thermoplastic insulation wire.  Just don't abuse it too much.

Subject: Where do I buy stuff?

	Try to find a proper electrical supply outlet near you.  Their
	prices will often be considerably better than chain hardware stores or
	DIY centres, have better quality materials, have wider variety
	including the "odd" stuff, and have people behind the counter that
	know what you're talking about.  Cultivate friendly knowledgeable
	sales people.  They'll give you much valuable information.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
Ferret list: ferret-request@ferret.ocunix.on.ca

Newsgroup: sci.electronics
Document_id: 53570
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - SunConnect ICNC)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>, swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) writes:
> 
> 
> I really don't know where to post this question so I figured that
> this board would be most appropriate.
> I was wondering about those massive concrete cylinders that
> are ever present at nuclear poer sites. They look like cylinders
> that have been pinched in the middle. Does anybody know what the
> actual purpose of those things are?. I hear that they're called
> 'Cooling Towers' but what the heck do they cool?

Water. Nuclear stations don't generate electricity directly from the
reactor, they use the reactor to generate heat. The heat is then used to
heat water just as in a conventional oil or coal station, and the
resultant steam drives the turbines.

The cooling towers are used to cool the steam and recondense it into water
to continue the cycle

Steve

-- 
Steve McKinty
Sun Microsystems ICNC
38240 Meylan, France
email: smckinty@france.sun.com	   BIX: smckinty

Newsgroup: sci.electronics
Document_id: 53571
From: markz@ssc.com (Mark Zenier)
Subject: Re: Trace size for a 15 Amp supply

R.G. Keen (rg@futserv.austin.ibm.com) wrote:
: A quick and dirty way to get higher current carrying capacity
: on PC board traces for one- or few-of-a-kind boards is to
: strip some #14 Romex house wiring cable to bare copper, form
: the bare copper to follow the trace, and solder it down.

And if it's not quick and dirty, you can get bus bars that
are stamped out with leads that insert in the PC board.

Mark Zenier  markz@ssc.wa.com  markz@ssc.com  



Newsgroup: sci.electronics
Document_id: 53572
From: craig@toontown.ColumbiaSC.NCR.COM (Craig S. Williamson)
Subject: Re: Looking for a good Spice book

In article <canright.734829385@convex.com> canright@convex.com (Robert Canright) writes:
|you might try
|"Computer-Aided Circuit Analysis Using SPICE" by Walter Banzhaf,
|at bookstores, paperback, ~$33, lots of examples. Dr. Banzhaf
|is a teacher.

Is there another book.  I have this one and don't find it helpfull in 
learning Spice.  It would make a good reference book but I found it lacking
for learning Spice.  Are there any others?

Craig

-- 
                                             "You took the bull by the horns
-Craig Williamson                              and stepped in something good."
 Craig.Williamson@ColumbiaSC.NCR.COM               - Balki Bartokomas
 craig@toontown.ColumbiaSC.NCR.COM (home)                 Perfect Strangers

Newsgroup: sci.electronics
Document_id: 53573
From: heke@stekt.oulu.fi (Heikki Paananen)
Subject: Re: How do DI boxes work?

In article <LANCER.93Apr15150228@oconnor.WPI.EDU> lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:

>   I'm doing sound for a couple of bands around here and we need Direct
>   Input boxes for the keyboards.  These are the little boxes that take a
>   line level out of the keyboard and transform it into low-Z for the run
>   to the mixer.  Sadly they cost like $50 (or more) each and I'm going
>   to need like 5 or 10 of them!  I looked inside one (belonging to
>   another band) and it looks like just a transformer.  Does anyone have
>   any plans for building them?  Perhaps in Anderton's "Electronic
>   Projects for Musicians" book (which I am having a hell of a time
>   tracking down...)?

An Easy way to solve the problem is to use two op-amps to form the
balanced low-Z output, but this solution does not provide any
galvanic isolation between keyboard (or whatever plugged) and
mixer. If no tight requiremets are demanded and some hum, snap,
crackle and pop sounds (formed by ground loops) can be tolerated,
the op-amp solution is just what you are looking for! (It is
cheap...somewhat $10/DI-box).
Not sure, but Craig Anderton did introduce one DI-box project
in Guitar Player mag years ago (transformerless).....

>   Thanks a lot!

Hope this helps. Email, if more details wanted....

>   - lancer@wpi.wpi.edu -                    - 0{{  MoDiMiDoFrSaSo: -
>   -   Mein Kopf ist ein Labyrinth, mein Leben ist ein Minenfeld    -

-----------------------------------------------------------------------
Heikki Paananen                           heke@stekt.oulu.fi
The University of Oulu                  
Department of electrical engineering      -Just a student
Finland
-----------------------------------------------------------------------
               Home is where the heart lies,
            but if the heart lies where is home?
                                           -Fish

Newsgroup: sci.electronics
Document_id: 53574
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: How do DI boxes work?

lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:


>I'm doing sound for a couple of bands around here and we need Direct
>Input boxes for the keyboards.  These are the little boxes that take a
>line level out of the keyboard and transform it into low-Z for the run
>to the mixer.  Sadly they cost like $50 (or more) each and I'm going

This is indeed one function, but more sophisticated ones do level control
and ground-lift (separating the keyboard and mixer earths) aswell.

>to need like 5 or 10 of them!  I looked inside one (belonging to
>another band) and it looks like just a transformer.  Does anyone have

Simple ones are just that - a transformer. A decent quality audio trans-
former will cost most of that $50. They are wired thus...


       HOT   --------------|  |----------------- HOT
                           )||(
     Input from            )||(                Balanced out to mixer
     Keyboard              )||(
                           |  |----------------- COLD
                           |
       GND   --------------|-------------------- GND

The ground-lift switch disconnects the GND line from the mixer. The
transformer ratio depends on the precise application, but around 10:1
turns ratio may be a good place to start.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
Document_id: 53575
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: MICROPHONE PRE-AMP/LOW NOISE/PHANTOM POWERED

davidj@rahul.net (David Josephson) writes:

>In <C5JJJ2.1tF@cmcl2.nyu.edu> ali@cns.nyu.edu (Alan Macaluso) writes:

>>I'm looking to build a microphone preamp that has very good low-noise characteristics,  large clean gain, and incorportates phantom power (20-48 volts (dc)) for a PZM microphone.  I'm leaning towards a good, low-cost (??) instrumentation amplifier to maintain the balanced input from the microphone, for its good CMRR, internal compensation, and because i can use a minimal # of parts.  

>>Does anyone out there have any experience, suggestions, advice, etc...that they'd like to pass on, I'd greatly appreciate it.

>Without doing anything really tricky, the best I've seen is the
>Burr-Brown INA103. Their databook shows a good application of this
>chip as a phantom power mic pre.

I've had very good results from the SSM2016 from PMI (part of Analogue
Devices). They have also now introduced the SSM2017 which looks good on
paper, but which I haven't tried yet.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
Document_id: 53576
From: dwo@zerberus.gud.siemens.co.at (F.Dwo)
Subject: DSP 56001

Hi !!!

Is there somebody using a 56001 DSP from Motorola ???
I am searching for programms concerning audio effects.
I built a 4 channel mixer (4ADC + 1DSP) for audio signals.
I built some digital filters and echos, but now i want to
include some effects like HARMONIC Equalizer or chorus.
The problem is, I dont know how these effects work (so I cant
write a programm).
So if someone has programms or just knows how such effects work,
please contact me in the newsgroup or via e-mail.
(Also if there are books about this problem)

Thanks in advance
(DWO)

Newsgroup: sci.electronics
Document_id: 53577
Subject: Re: Cable TVI interference
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1qevrf$4t@hpscit.sc.hp.com>  writes:
> 
> As is typical nowadaze, you will probably have to do somebody else's job
> for them. Although this shouldn't be needed, you might take a few minutes
> to wander around the neighborhood with an HT sniffing for cable leakage
> on your freq. after shutting down your system for a while. 
> 
> If you are fortunate enough to the find the hole, call the cable company and
> get the highest link in the chain of command you can. Explain the problem,
> whose job it really is to maintain THEIR equipment, and how much of a nice
> guy you are to have tracked down THEIR problem for them.
> 
> You may have been lucky and made a new contact that could be helpful in the
> future.
> 
> You should always try the 'honey' approach before bringing out the
> Jack Nicholson impressions.....  >:-)
> 
> This has worked for me in the past with the power company when tring to 
> find loose/noisy high voltage lines/hardware. Only once did I have to
> tell them I was narrowing the problem down to a specific pole by bumping
> a whole line of poles with my car. Got 'em out there THAT NIGHT. And, they
> didn't have to meet Jack!
> 
> As a disclaimer, THEIR method for finding loose hardware was usually
> whacking the poles with a huge sledgehammer after their high tech arc-
> finding 'scope couldn't find the problem.
> 
> 
> 
> Bill
> wb6 rotten zucchini garden

Here in switzerland, the situation is exactly the same. The cable tv companies  
even tried to stop amateur radio in switzerland in the beginning of cable  
tv(they seem to be too stupid to know anything about international frequency  
conferences or so). Even today, they use the cheapest possible coax running  
into problems they can't solve anymore. As Bill noted, the only way is to look  
for a solution with the neighbours *BEFORE* calling for the cable tv guys or  
the fcc. The chance to find neighbours with some sense for reason is by far  
bigger than with these people (especially the first ones). As anywhere in an  
administration people don't like, if You tell them to work for the money they  
get...
The problem is, that radio amateurs don't have the power to put trough their  
rights in all cases. So let's hope they start soon with optical fibers and get  
out of our freqencies.


Cheers   Robert  (HB9NBY)
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
Document_id: 53578
From: mkaschke@oasys.dt.navy.mil (Martin Kaschke)
Subject: 4-Band Equalizer


    I was wondering if anyone out there in net-land knew of a SIMPLE
way to make a 4-band equalizer (single channel).  I need it to accept
LINE inputs (tape deck, CD player, etc.) and output to the same! So
input impedance should equal output impedance.  Also, since I am driving
a line, I would need 1 volt p-p output.  Final requirement is that I
can either:
	      1. Control it digitally
			OR
	      2. Control it easily, or with few resistors

FINALLY - If anyone knows of any FILTER or EQUALIZER chips, that might
be useful, please let me know. (I have seen a couple of them from NATIONAL,
and MAXIM).  Thanks in advance,
				  Martin

Newsgroup: sci.electronics
Document_id: 53579
From: Arthur_Noguerola@vos.stratus.com
Subject: Re: Adcom cheap products?

In article <C5K177.BoK@world.std.com> rogerw@world.std.com (Roger A Williams) wrote:  
>mdonahue@amiganet.chi.il.us (Mike Donahue) writes: 
> 
> 
>>I do NOT know much about Adcom Mobil Audio products, but I DO know for a fact 
>>that ADCOM does NOT make its own "High End" Home Audio Equptment and that 80%+ 
>>of it comes directly out of Tiawan... 
> 
>Like most high-volume manufacturers, Adcom has most of its PC boards 
>assembled off-shore (in their case, mostly in the far east).  Final 
>assembly _and testing_ are done in East Brunswick. 
> 

          and of course you older folks on the net will remember 
          way back when Adcom got its RAVE reviews and kudos (ca 
          1985  or  so)  their  555 amp and preamp WERE not only 
          designed here but built here in  the  USA.  then  they 
          went  to  mexico  and then to taiwan right after their 
          sales  skyrocketed   because   of   their   Stereopile 
          review!!!  if you have units that old look for MADE IN 
          --- stickers on your unit. 


Newsgroup: sci.electronics
Document_id: 53580
From: baldur@rsp.is (Baldur Thorgilsson)
Subject: receiver system


Dear Netters
I want to send EMG-signals from a running person to a computer. 
Each signal is 4KHz wide and there is up to 30 of them on each
running person. The signal is only to be sent over a few hundred 
meters. It seems to me that the frequency intended for this use is
about 150MHz and about 440MHz.
To make the transmitters as light as possible I suppose it will be best 
the to send the signals in an analog form. As this application is rather 
specialized I do not expect to be able to buy the exact transmitter-
units i need.
On the other hand I imagine that I can buy the receiver somewhere. I 
need a multichannel (up to 30 channels) receiver or 30 complete  
receivers in some rack system where one can add as many receivers 
as needed in the particular case.
DO ANYBODY KNOW IF THERE IS EXISTING SUCH RECEIVER 
SYSTEM ON THE MARKET?

baldur@rsp.is     (TF3BP) (please respond by email rather than nn)

Newsgroup: sci.electronics
Document_id: 53581
From: then@snakemail.hut.fi (Tomi  H Engdahl)
Subject: Re: Telephone on hook/off hok ok circuit ~

In article <1ptolq$p7e@werple.apana.org.au> petert@zikzak.apana.org.au (Peter T.) writes:

>Since an on-hook line is aprox 48-50V, and off-hook it usually drops below 10V.
>How about an LED in series with a zener say around 30V.
>On-hook = LED on
>Off-hook = LED off.
>Would this work? If anyone tries/tried it, please let me know.

Not recommended. Your circuit would take too much current, when
telephone is on-hook. Telephone company does not like it.


--
Tomi.Engdahl@hut.fi  !  LOWERY'S LAW:
then@niksula.hut.fi  !  "If it jams - force it. If it breaks,
                     !   it needed replacing anyway." 
* This text is provided "as is" without any express or implied warranty *

Newsgroup: sci.electronics
Document_id: 53582
From: webb@itu1 (90-29265  Webber  AH)
Subject: Re: Adcom cheap products?

: >I want to upgrade my system and was thinking of buying Adcom seperates.
: >I have heard from alot of people, though, that Adcom sounds great but
: >that the components are made cheaply and therefore won't last very long.
: >The time estimates I've heard are like only 3 or 4 years.  Is this true?

I own the Adcom 60W power amp.  As far as I'm concerned, there's no
  amp which can touch it at the price range.
The build quality is very impressive and is far superior to other 
  amps in the price range.  The whole amplifier is extremely solid
  with massive heat sinks and very solid casing.
If you open the amp up, there are only very good quality components 
  in and the amp seems to be designed extremely well.  Perfect
  symmetry for both channels and TWO transformers - one for each
  channel.  The binding posts on the back of the amplifier are
  virtually the same as those on the Classe model 70 ie. very good.

I was also sceptical about the amps being built in the far-east
  or where-ever.  But if you look in the amp and see what components
  they use and how it was designed, you can easily see why the
  amplifiers sound so brilliant.
I cannot see why people say the amplifier won't last - not with
  those quality components inside.  Sure the amp runs very fairly
  hot - but that's how you get an amp to sound incredibly good.

My last point, I recently auditioned the Adcom preamp something like
  the 545 or something.  It was two years old and it still sounded
  like new.

If you build an amplifier decently, like the Adcom's, they will
  sound brilliant and last a long time - period.

Just my thoughts, but then - I do own one of Adcom's amps.

--
***********************************************************************
**    Alan Webber                                                    **
**                      webb@itu1.sun.ac.za                          **
**                      webb@itu2.sun.ac.za                          **
**                                                                   **
** The path you tread is narrow and the drop is sheer and very high  **
** The ravens all are watching from a vantage point near by          **
** Apprehension creeping like a choo-train up your spine             **
** Will the tightrope reach the end; will the final couplet rhyme    **
***********************************************************************

Newsgroup: sci.electronics
Document_id: 53583
From: mabbot@stellenbos.csir.co.za (Mike Abbot)
Subject: High level language compilers for uControllers ?

Howdy chaps

Has anybody got any pointers to good C, Pascal, etc compilers for 
microcontrollers, shareware or otherwise ?

My specific need is for 8051 C, but if the responses are many and varied I 
will post a summary.

Cheers
Mike


Mike Abbott	mabbot@stellenbos.csir.co.za
Cape Town	mabbot@fred.csir.co.za
South Africa

Newsgroup: sci.electronics
Document_id: 53584
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Illusion

I missed the first article[s] on this line due to not having a
chance to read the news for a couple of days...

The idea is commercialized in at least one product, the Private
Eye.  That's a small cube-shaped device that the user straps around
the head similar to a sweat band.  There is a boom that comes from
the side on which the device is mounted so that it is positioned
in front of the user's eye.

The Private Eye we had here for evaluation was Hercules-MDA
compatible.  The innards are a row (~400 LEDs) that are swept up
and down by a galvonometer-like movement.  The result is that the
sweeping LED bar forms a fused raster.  There is a virtual image
projected in front of the user that the visual system tends to fuse
with the background.

I didn't like the device very much.  I found it easiest to use if I
looked at a blank white wall.  I had problems with focus tracking
if I glanced down to look at my keyboard for an out-of-the-way key.
The unit also emitted a soft buzz and vibration which I found
annoying.  Some people didn't seem to mind the buzz.  Properly
used, however, the image clarity was quite crisp.

I don't know if the company has taken the technology any further in
the last year or two, but it did seem to have promise.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53585
From: Michael_LaBella@vos.stratus.com
Subject: Re: Adcom cheap products?


>Off-shore assembly is one reason that Adcom is able to make products 
>that perform as well as those from people like Audio Research and Van 
>Alstine (and better than Hafler and Forte'), but at a much lower cost. 

How do you spell "tuna helper" ? 

I gather by off-shore assembly you mean that adcoms are built by 
blue-fin tuna's who are into that squid-fi sound?  (I agree on that one). 
My Adcom 555 preamp did sound better after installing the famous  
"running the chips class "A" resistor mod", and replacing the metal 
bottom cover with plexiglass,, too bad the factory could not make em sound 
better,, but better sound, unfortunately, does not appear to be a priority 
with Adcom, else the mods would neither have been necessary, nor would they 
have improved what was already touted as superlative state-o-d-art le'sound. 
I really want to hear from all those people out there who have traded up  
from an sp9II (even an sp3a!) to a GFP-555/etc., or maybe from those that 
have dumped their forte' amps for a GFA-555/etc....  



Newsgroup: sci.electronics
Document_id: 53586
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Adcom cheap products?

I have an Adcom GFA-555 that I got in 1985.  There certainly isn't
anything magic about it.  The components used are decent, but
nothing uncommon with respect to consumer grade components.

The GFA-555 is a nice piece of equipment.  I'm glad that Adcom had
the guts to not over-do the packaging.  It irks me when I see
audiophile oriented equipment whose case and heat sinks probably
cost much more and receive more attention than the electronics they
are supposed to serve.

I don't see any big deal about the geographic region in which
something is assembled.  This is especially true for something as
low-technology as a GFA-555.

I'd hope that a GFA-545 would still work well after several years.
Except under conditions of extreme abuse, there isn't much there to
go wrong.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53587
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1993Apr15.103953.66252@cc.usu.edu>  writes:
> In article <C5Hs5J.AG7@bcstec.ca.boeing.com>, rgc3679@bcstec.ca.boeing.com  
(Robert G. Carpenter) writes:
> 
> |> It seems reasonable to me that a microwave transmitter-receiver setup  
could 
> |> do the job. For example, say you want to map an acre lot, it'd be  
convenient
> |> to place MW transmitters around the lot's periphery (either 2 or 3) and  
then
> |> carry a hand-held recorder and walk to a point on the lot, press a button  
and
> |> the coords of the recorder's location is stored as digital data.
> |> 
> |> What's the chance of this working? Any systems like this already exist?
> |> What kind of accuracy could you expect? What would something like this
> |> cost to prototype? Is there a better alternative than microwaves?
> 
> Of course you could develope this system, but there is already a system  
called Global
> Positioning Satellites.  It gives three dimensional coordinates anywhere on  
earth. 
> Many surveyors use this system with a differential receiver/transmitter to  
get
> coordinates within centimeters.  Basic receivers with resolution of a few  
meters (on
> a good day) are available from many sources.
> 
> 
> -- 
> WMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMWMW
> 
>   \_      \_  \_\_\_    \_\_\_               Weston R Beal
>    \_      \_  \_    \_  \_    \_         sldf3@sol.ee.usu.edu
>     \_  \_  \_  \_\_\_    \_\_\_            sldf3@cc.usu.edu
>      \_\_  \_\_  \_  \_    \_    \_       Electrical Engineer
>       \_      \_  \_    \_  \_\_\_       Utah State University
> 
>   "That's the wonderful thing about crayons; they can take you to
>    more places than a starship can."    - Guinon
> 
> 

Thought it means Global Positioning System. There are two precision levels, one  
for army applications (killing has to be very accurate today) and one for civil  
ones. The civil precision is about 20 to 30m (correct me, if I'm wrong),  
though, it may be insufficiant for mapping buildings. But there is a way with  
an additional reference point (e.g. one fixed GPS system in a house) to get the  
same high precision as the military version, but it gets pretty complicated  
then. If You use a microwave system (actually this means some type of radar),  
You need quite a lot of number crunching to get accurate vectorized data out of  
Your original signals. So the GPS system seems to be the better (and running)  
idea for Your application(there have been discussions in this newsgroup, don't  
know of an address anymore).

Cheers    Robert   (HB9NBY) 
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
Document_id: 53588
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: mysterious TV problem -- source?

If the set is direct line powered, try checking the [likely to be
there] hybrid regulator module down stream from the 170 volt
supply.  Several sets I've looked at use a 135 volt regulator.  The
regulators have a tendency to short out, making the safety circuits
shut down the EHT supply section.

Try putting the set on a Variac or adjustable transformer and lower
the AC input voltage to the set to about 90 volts.  If the set
operates nromally, then you know you've got a shorted regulator.

There are myriad other areas for problems, but I've seen the one
above several times.  Also, if the set uses one, the trippler
module may be shot; that's fairly common.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53589
From: larryhsu@mtl.mit.edu (Lawrence Hsu)
Subject: Shrunken monitor window?

Does anyone know what causes the ever-growing black border around the
edges of my computer screen?  The growth has been gradual so I don't
know how long it's taken to get this bad.  I have a 19" DEC (?)
color monitor, maybe five years old, and the black border is about 1.1
inches on the left and right sides, about 1.75 inches on the bottom and
negligible at the top of the screen.  The only controls are
brightness knob, contrast knob, deGauss switch, and power switch.

Is there anything to be done, or are the monitor's days numbered?

Larry Hsu
larryhsu@mtl.mit.edu

Newsgroup: sci.electronics
Document_id: 53590
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dumb Question: Function Generator

1)  Output offset:  Obtain the service manual for the oscilloscope
and adjust the internal output offset contorl.  There is virtual
certainty that there is an internal ajustment for the offset
control's zero detent position.

2)  Verify that the function generator is properly loaded.  Many
generators expect you to supply a 50 ohm load.  Go to a hamfest
flea market and scrounge around for a pass-through 50 ohm
terminator that has a male and female BNC (or whatever) connector
on it.  The calibrator on my Tektronix scope is designed to put out
.4v into a 1 meg load, but .1 volt into a 50 ohm load.  You may
also find that loading the output of the function generator also
reduces the harmonic distortion.

Build an attenuator.  You don't have to use (and I wouldn't want to
use) the input impedance of the device under test as part of the
voltage divider to drop the input test voltage.  Consider this:

------10K--------+---------? ohm ----
                 |
Gen            50 ohm            D.U.T.
(loaded)         |
-----------------+-------------------

Think about the ratio of 50/10K and then think about the accuracy
to which you can read voltages on your oscilloscope.  You can
virtually discount the loading of the D.U.T.  Also you have the
millivolt test generator you want.

Good luck,


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53591
From: seema@madvlsi.columbia.edu (Seema Varma)
Subject: IC Packages

Hi,
	I am looking for some help in choosing a package
for a high-speed silicon ADC (100Mhz) currently being 
fabricated. This is a PhD research project and I have to test
the chip at speed on a PCB. I expect to have roughly 100
packaged circuits and will do DC, low-speed and high-speed
testing using 3 different set-ups for the test chip.
 	
	I know for sure that a DIP will not work
(the long lead lines have too high an inductance).
Getting a custom-made package is too expensive, so
I am trying to choose between a flatpak and a
leadless chip carrier. The flatpack would be hard
to test since it has to be soldered on to the test
setup and I would spend loads of time soldering 
as I kept changing the test chip. The leadless chip
carrier sockets also have long lead lines and may
not work at high speeds.
 
	Does anyone out there have experience/knowledge
of this field ? I would greatly appreciate help! Any ideas/
names of companies manufacturing holders/sockets/packages
would help. 
 
P.S. The multi-layer fancy GaAs packages seem like a bit
of overkill(?)
	
 --- Seema Varma

Newsgroup: sci.electronics
Document_id: 53592
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Just to complete that thought, the cooling towers cool water that
circulates through heat exchangers that recondense the turbine
exhaust back into feedwater for the heat exchangers that transfer
energy from the reactor's cooling circuit.


  |---------------|   |------turbine, etc---|  |---------|
  |                >   >                    >   >        .
reactor            <   <                    <   >        .
  |                >   >                    >   >        C. T.
  |---------------|    |--------------------|  |----------

The reactor has a closed loop circuit to prevent radioactive
contamination of the the turbine feedwater.

The cooling tower is a separate circuit to avoide contamination of
the turbine feedwater with atmospheric contamininats, etc.
Purifying boiler feedwater is important business at both fossil
fired and nuclear generation facilities.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53593
From: jmains@engr.latech.edu (John P. Mains)
Subject: Electrical Properties of ELASTOMERS


Hello,

I am looking for carbon-doped rubber.    Or an highly elastic material that changes its resistivity, or some
other electrical property when streched.

If you could email me any info you may have on material names or companies that make the stuff
it would be highly appreaciated.

Thanx
JP
Biomedical Engineering
Louisiana Tech University 

Newsgroup: sci.electronics
Document_id: 53594
Subject: Re: Picking up cable tv with an aerial.
From: ganter@ifi.unibas.ch (Robert Ganter)

Great, the first advantage of cheap coax, I've ever heard.

Cheers   Robert  (HB9NBY)

--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
Document_id: 53595
Subject: Re: What do Nuclear Site's Cooling Towers do?
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>  writes:
> 
> 
> I really don't know where to post this question so I figured that
> this board would be most appropriate.
> I was wondering about those massive concrete cylinders that
> are ever present at nuclear poer sites. They look like cylinders
> that have been pinched in the middle. Does anybody know what the
> actual purpose of those things are?. I hear that they're called
> 'Cooling Towers' but what the heck do they cool?
> I hope someone can help 
> 

This is definitely the wrong newsgroup for this, but never mind.
Any machine powered by heat (motor, steam- or gasturbine, steamengine,  
thermoelement,etc) work the better, the bigger the temperature difference  
between input and output is. Because You never get all thermic energy out of  
the powering medium (steam, burning gaz, etc), You have to eliminate the rest  
of the energy to keep the efficency high. A thermal electric power plant (coal,  
oil or atomic power) works just the same way. You heat water (steam) to power  
the turbine and generators. Because You don't get the whole energy out of the  
steam (efficency is never 100%) You have to cool down this steam again by  
something else. Most power plants use cooling towers for this purpose (some  
type of mega-refrigerator...). Others use water of a river (ecologically not  
unobjectionable). Got it ?

Cheers   Robert  (HB9NBY)
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
Document_id: 53596
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Re: A question about 120V

>>SO..  Here's my question.  It seems to me that I'd have the
>>same electrical circuit if I hooked the neutral jumper from the
>>neutral over to the ground screw on new 'three prong' grounding
>>outlets. What's wrong with my reasoning here?

>First, go to the local hardware store and pick up a copy of "Wiring
>Simplified" by H.L. Richter.  Now if your house is wired with metal
>conduit, you don't need a seperate ground wire (assuming the house
>is wired correctly and the pipes are connected to a cold water
>pipe in your basement).  The outlets that have a neutral hooked to
>the ground screw seem wrong.  Anyone else think so?

Back in the 70's I was a service technician for a cash register company.
The cash registers used microprocessor circuits and back then they were
VERY susceptible to electrostatic discharge and line noise.  The biggest
problems came from outlets that were not properly grounded.

In almost every place we went to do an installation, we found outlets
with the ground connected to the neutral.  For 99.9% of the things you
can plug into one of these, they work fine.  For our cash registers they
were a nightmare -- line noise tended to scramble the memory
periodically.

With modern electronics using switching power supplies this should be
less of a problem.  Even the company I used to work for is no longer
recommending a dedicated line with a seperate ground for their
equipment.  I imagine if you check MOST household wiring you will find
that the ground and neutral are connected.  Although not ideal, it
should be o.k. for most applications.

---
 . SLMR 2.1 . My reality check just bounced.
                                
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
Document_id: 53597
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Husky Programmer bits req'd

Help !! - I'm looking for a ISA driver card and driver software for a
Logical Devices Husky programmer (It aint mush good without these)
can anyone help with either of these items ?
cheers
Mike.

Newsgroup: sci.electronics
Document_id: 53598
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: receiver system

One thing to consider is time division multiplexing the EMG
channels to reduce the number of RF carriers you have to generate.
If you multiplexed the EMG inputs at 10KHz, that would probably be
sufficient for most physiology studies (you'd have ~ 330 Hz per
channel sampling rate.)  That level of analog multiplexing should
be rather easy to accomplish.

Combining a lot of RF carriers is pretty tricky to do without
generating intermodulation.  A system to be carried by a runner is
in a fairly harsh environment and would probably be difficult to
keep balanced.

A commercial hand-held transciever could probably be employed with
a little modification to accomodate widening the bandwidth.
Obviously, this has to be done in accordance with whatever laws
govern the use of transeivers in your location.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53599
From: cam@castle.ed.ac.uk (Chris Malcolm)
Subject: CASIO SF7500 SERIAL LINK

The Casio 7500 lectric diary has a 3-wire serial interface with param
setting like RS232, for which one get a magic but expensive cable to
connect to a PC. Does anyone know the spec of this interface, e.g., it
needs inverting and boosting from CMOS signals to match RS232 lines?
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205

Newsgroup: sci.electronics
Document_id: 53600
From: garyg@warren.mentorg.com (Gary Gendel)
Subject: Re: A question about 120VAC outlet wiring.

In article 1834@cmkrnl.com, jeh@cmkrnl.com writes:
>In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
>> SO..  Here's my question.  It seems to me that I'd have the
>> same electrical circuit if I hooked the jumper from the neutral
>> over to the ground screw on new 'three prong' grounding outlets.
>> What's wrong with my reasoning here?  
>
>What you CAN do if you want three-prong outlets without additional wiring is 
>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>depending on where you are putting your new outlet(s), a GFCI may be *required*.

You still need to supply a proper ground for a Ground Fault Circuit Interrupter!
So rewiring is still a part of this job, however, the ground may be connected to
a local earth ground, rather than back at the breaker box.

As Jamie said, GFCI devices are required by code in a number of places, most
notably: bathrooms, and outside the house.  I do suggest the use of GFCI outlets,
rather than the breakers.  You will end up with much less headaches.  Noise pickup
in long cable runs is sometimes enough to cause frequent tripping of the breakers.

GFCI devices do save lives, if you decide to install them, be sure to check them
regularly (using the test button).

Running the family business (electrical supplies and lighting) for many years, I
have seen too many seasoned electricians fried, because they forgot to double check
their common sense list.  Please exercise caution.
---
			Gary Gendel
Vice President:				Current consulting assignment:
Genashor Corp				Mentor Graphics Corporation
9 Piney Woods Drive			15 Independence Boulevard
Belle Mead, NJ 08502			Warren, NJ 07059

phone:	(908) 281-0164			phone:	(908) 604-0883
fax:	(908) 281-9607			email:	garyg@warren.mentorg.com








Newsgroup: sci.electronics
Document_id: 53601
From: LLBGB@utxdp.dp.utexas.edu
Subject: chip / chipset for code 39 barcode?

Distribution: usa
Reply-To: lihan@ccwf.cc.utexas.edu

While I'm on the net bugging everyone, is there such a thing as a chip
or chipset to decode Code 39 barcode?  I ask for a couple of reasons --
mainly I want a reasonably compact encoding scheme to write information
on magstripe cards and Code 39 appears to be about right.  (If the 'right'
way to do it is something else, and it's reasonably easy, can someone let
me know?)

I might not get a chance to reply too quickly to this or my earlier post,
but I'll get to them within a couple days, I think ..

thanx everyone!  <BGB>  lihan@ccwf.cc.utexas.edu


Newsgroup: sci.electronics
Document_id: 53602
From: donrm@sr.hp.com (Don Montgomery)
Subject: Radio Shack Battery of the Month Club


Radio Shack has canceled their "Battery of the Month" Club.  Does 
anyone know why?  

They say they'll honor existing cards in customer hands, but no new
cards will be issued.

Don Montgomery
donrm@sr.hp.com


Newsgroup: sci.electronics
Document_id: 53603
From: johne@vcd.hp.com (John Eaton)
Subject: Re: What do Nuclear Site's Cooling Towers do?

-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:
: 
: 
: I really don't know where to post this question so I figured that
: this board would be most appropriate.
: I was wondering about those massive concrete cylinders that
: are ever present at nuclear poer sites. They look like cylinders
: that have been pinched in the middle. Does anybody know what the
: actual purpose of those things are?. I hear that they're called
: 'Cooling Towers' but what the heck do they cool?
: I hope someone can help 
:-----------------------
During the nuclear fission reaction the uranium fuel can get hot enough
to melt. When this happens the liquid uranium is pumped to the cooling
tower where it is sprayed into the air. Contact with the cool outside air
will condense the mist and it will fall back to the cooling tower floor.
There it is collected by a cleaning crew using shop vacs and is then
reformed into pellets for reactor use the next day.

Cooling towers are a lot taller than they really need to be. Power companies
are forced to make them that tall by some enviromental law that requires the
raw uranium emisions to be held to under 1%. This law is now under attack
by lawyers arguing that the 1% should be measured at the edge of the property
rather than the edge of the cooling tower. Eliminating this law will save
power companies thousands of dollars in concrete costs for new nukes.

John Eaton
!hp-vcd!johne



Newsgroup: sci.electronics
Document_id: 53604
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Ungrounded GFCIs; was: Re: A question about 120VAC outlet wiring.

In article <1qmisf$odp@sdl.Warren.MENTORG.COM> garyg@warren.mentorg.com writes:
>>
>>What you CAN do if you want three-prong outlets without additional wiring is 
>>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>>depending on where you are putting your new outlet(s), a GFCI may be *required*.
>
>You still need to supply a proper ground for a Ground Fault Circuit Interrupter!

Oddly enough, you don't, at least according to the wiring FAQ that
is regularly posted on misc.consumers.house.

A GFCI senses discrepancies between the live and neutral wire currents,
and cuts them both off if a discrepancy is found.  No ground connection
is needed for it to function.



-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53605
Subject: Re: Looking for a good Spice book
From: juhan@piko (Juhan Poldvere)

In <C5GIA7.7x9@acsu.buffalo.edu> NEIL B. GANDLER 
   (v064mb9k@ubvmsb.cc.buffalo.edu) wrote:

:>   I am an electrical engineering student and its a must that I get familiar
:> with spice. I have been using it and getting used to it but it would
:> be great to have a good reference manual that explains everything in an
:> organized and concise. I current have "A guide to circuit simulation &
:> Analysis using spice". I feel it has the information is just randomly placed
:> in the book and its not easy to look up small things when you just
:> need a good reference book. I would appreciate any info. Thanks

There is a postscript manual at ic.berkeley.edu in pub/spice3/um.3f.ps
directory (about 650kbytes, 126 pages).
--
Juhan Poeldvere, ES5QX                               | juhan@chem.ut.ee
Tartu University, Dept. of Chemistry                 | fax:   372 (34) 35440
2 Jakobi St., EE-2400, Tartu, Estonia, via Stockholm | voice: 372 (34) 35429

Newsgroup: sci.electronics
Document_id: 53606
Subject: 2SC1096, 2SA634 specs?
From: juhan@piko (Juhan Poldvere)


Hi,
Could some kind soul post me the max power/voltage/current ratings of
2SC1096 and 2SA634 transistors, their conductance types and pinouts.
They are used in the sweep portion of a TV set.
Thanks in advance,
--
Juhan Poeldvere, ES5QX                               | juhan@chem.ut.ee
Tartu University, Dept. of Chemistry                 | fax:   372 (34) 35440
2 Jakobi St., EE-2400, Tartu, Estonia, via Stockholm | voice: 372 (34) 35429

Newsgroup: sci.electronics
Document_id: 53607
From: aras@Ziggy.csl.ncsu.edu (Caglan M. Aras)
Subject: Polaroid Range finder interference-Help!

We have a setup with with 13 polaroid transducers and rangefinders. We
would like to fire these three at a time with about 5 ms between
firings. The three that are being fired do not fire in the same
direction. 

To further explain the situation, assume we are firing sonars A,B,C
5 ms apart each other. We should normally see an echo on A that
corresponds to the distance. However, sonar A detects the INIT line
of sonar B! The detection is actually through the transducer of sonar A;
we can see a very faint 50Khz signal on the transducer, exactly at the
time the init line of sonar B is activated. 

We feel that there is some ground coupling that is causing this interference.
We came to this conclusion since we are using a separate power supply
for sonars B and C. 

Has anyone else had any problems with these particular units and
this type of experience? Your suggestions for remedies will be greatly
appreciated.


-- 
Caglan M. Aras                 [] aras@eceris.ece.ncsu.edu
ECE Department                 [] ph: 919-515-5405
North Carolina State University[] fx: 919-515-5523
Raleigh, NC 27695              []

Newsgroup: sci.electronics
Document_id: 53608
From: jra@law7.DaytonOH.NCR.COM (John Ackermann x 2966)
Subject: Single chip receiver for FSK?

My next project is to come up with an IF/detector module for fast -- 112
to 250 kB/sec -- packet radio use.  No fancy modulation scheme, just
wide FSK for use at 902 or 1296 MHz.

I'm a bit familiar with the Motorola 3362 chip, but I wonder if there
are newer designs that might work at higher input frequencies.

My goal is to come up with an inexpensive design for a receiver "back
end" with IF input on one end and an FSK demondulator on the other.  I'm
particularly interested in ways to use a higher IF than 10.7 -- do any
current chips work up to, say 150MHz with internal downconversion so a
normal IF filter can be used?

Any suggestions?

John

-- 
John R. Ackermann, Jr.         Law Department, NCR Corporation, Dayton, Ohio
(513) 445-2966		       John.Ackermann@daytonoh.ncr.com
Packet Radio: ag9v@n8acv.oh    tcp/ip: ag9v@ag9v.ampr [44.70.12.232]

Newsgroup: sci.electronics
Document_id: 53609
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Re: History question

In article <kazel.15.734728882@uiuc.edu> kazel@uiuc.edu (Mitch Kazel) writes:
>Sorry if this isn't the correct news group . . . but . . .
>
>A colleague of mine is trying to find out when the first public use of 
>electronic voice amplification was  . . . i.e. a P-A system.
>
>Any reference would be appreciated.  Please reply via e-mail.

>Mitch Kazel (N9HDQ)
>INTERNET:  kazel@uiuc.edu

This is vague, so I am posting it in case anyone else knows more.

I recall reading of a phonograph which used mechanical amplification.
Compressed air was squirted out of a valve which was controlled by the
pickup.  The result was noisy and distinctly lo-fi, but much louder
than a conventional phonograph.  It tended to wear the disks out
pretty quickly though.

Paul.
-- 
Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
Document_id: 53610
From: horne@cs.utexas.edu (Patrick J. Horne)
Subject: Thermal fuse supplier wanted

I have a thermal fuse from a Apple Laserwriter II power supply (Made
by Cannon) that I need to replace.  The fuse is not the standard
tubular thermal fuse like those found in hair driers etc, but is a 
rectangular plastic package, much like a transistor or diode.  It
is about 0.2"x0.2"x0.1", with both leads coming out of one of the
0.1"x0.1" sides.  I have been told that it was made by MITI, a asian
company, but I can find no information as to a supplier.  This fuse
is rated at 1A, 130C.  Does anyone have a source for this fuse?  I
only need 5 or so, which means that the manufacturer wouldn't even want
to talk to me, let alone, deal with me.

Please advise via E-mail.

Thanks,
Pat

-- 
---  I like boats and bicycles, they're healthier than Valium  ---
Pat Horne, Network Manager, Shop Supervisor, Hardware Guru 
CS Dept, University of Texas, Austin, Tx. 78712 USA 
voice (512)471-9517, fax (512)471-8885, UUCP:cs.utexas.edu!horne

Newsgroup: sci.electronics
Document_id: 53611
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: $25 network

>>The same folks now have out LBL (Little Big Lan) for $75.  I think you
>>get it for $50 if you already own $25 Network.  LBL works with Arcnet,
>>parallel ports, and serial ports in any combination for up to 250 or so
>>nodes.

No flames please, but I picked up this discussion a bit late and I 
am really curious...

What exactly *is* the $25 network?
Something to hack together N serial cables?
Something with N serial drivers?

Thanks,
Pat

Newsgroup: sci.electronics
Document_id: 53612
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: TDR plug-in

If anyone out there has an HP180 series scope or mainframe, I
have the TDR plug in (the 1810, I believe) for it and have no need
to keep it. Interested? E-mail me.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 53613
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Emulator pods

A surplus-dealing buddy of mine came up with two emulator pods:

	HP64220C (for HP 64100 development station). 8086 target
	processor. DIP head. Does not include board that plugs into
	the 64100.

	Applied Microsystems 80C186/188 pod, LCC head.

If you have an interest in either, let me know. They look to
be in excellent condition. He doesn't know what to do with them, which
may mean that they'll be cheap.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 53614
From: bill@xpresso.UUCP (Bill Vance)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

Dean Anneser (anneser@pwa-b.uucp) wrote:
: My 9 yr old son has signed up to do a science report on batteries.  I was
: wondering if anyone could provide me with some information as to how to
: construct a home-built battery.  In my grade school days, I remember seeing
: the 'ice cube tray' version, but I don't remember what to use as a good
: electrolyte or what the easily obtainable metals were.  

: Thank you in advance.

: Dean W. Anneser                  Pratt & Whitney Aircraft     
: Computer System Specialist       m.s. 161-05                       \__ -\  
: (203)565-9372 (desk) 5016 (fax)  400 Main St.               Ooo.. (_)-V/( )
: Uucp:     uunet!pwa-b!anneser    East Hartford, CT  06108    Live to Ride
: Internet: anneser@pwfire.pweh.utc.com
: "One test result is worth one thousand expert opinions" -- Wernher Von Braun 
: -- 
: Dean W. Anneser                  Pratt & Whitney Aircraft     
: Computer System Specialist       m.s. 161-05                       \__ -\  
: (203)565-9372 (desk) 5016 (fax)  400 Main St.               Ooo.. (_)-V/( )
: Uucp:     uunet!pwa-b!anneser    East Hartford, CT  06108    Live to Ride

--

The simplest one is easy.  Take a lemon or other citrus type fruit, and
stick a pair of metal strips into it for the contacts.  The two strips must
be of disimelar metals like copper and zinc.  Then connect a voltmeter to
the contacts and read the voltage.

bill@xpresso.UUCP                   (Bill Vance),             Bothell, WA
rwing!xpresso!bill

You listen when I xpresso, I listen When uuxpresso.......:-)

Newsgroup: sci.electronics
Document_id: 53615
From: miller@hmsp04.wg3.waii.com (Griff Miller X7114)
Subject: Re: 68000

In article <1993Apr15.060043.15664@serval.net.wsu.edu> rwilley@eecs.wsu.edu (Ronald Willey - CS) writes:
>
>	The Supra accelerator that is mentioned in one of the pervious
>articles, is not 68000 or 68020 based.  It runs on a 68030 at 28Mhz and 
>the design they are using is very simple( if you were referring to the
>A500 exteranal model).

Hmm - I don't think you and I are thinking of the same thing. I was the
original poster, BTW. The accelerator that I'm talking about almost
certainly uses a 68HC000, according to the footnotes in the Supra ad. It
only costs $199 list, so I really doubt if it has a 28 MHz 68030 inside.

It's called the Supra 28, or Supra Turbo 28.
There's an external A500 model, and an internal A2000 model.

BTW, does anyone know if a 28Mhz 68HC010 exists?
--
Griff Miller >  Griff.Miller@waii.com  < use this for email.

      *** My opinions are mine, not Western's. ***

"Dear friend, do not imitate what is evil but what is good.
 Anyone who does what is good is from God. Anyone who does
 evil has not seen God." - 3 John 9

Newsgroup: sci.electronics
Document_id: 53616
From: bps@ektools.kodak.com (Bruce P. Sidari)
Subject: Re: A question about 120VAC outlet wiring..

In article <1993Apr15.212629.1834@cmkrnl.com> jeh@cmkrnl.com writes:
>In article <1993Apr14.172145.27458@ecsvax.uncecs.edu>, crisp@ecsvax.uncecs.edu (Russ Crisp) writes:
>> I'm considering modernizing some old wiring in my home, and
>> I need a little advice on outlet wiring.  Several outlets
>> are the old 'two prong' type, without the ground.  Naturally,
>> the wire feeding these outlets is 12/2, WITHOUT the ground
>> wire.  I noticed at the fusebox that some circuits have the
>> 12/2 with ground, and that on these circuits, the ground
>> wire was tied to the same bus as the neutral (white) wire.
>
>They are supposed to be connected together at the breaker panel... but nowhere,
>repeat NOwhere, else.  (Well, almost.  There are strange exceptions for things
>like sub-panels.)
>
>
>	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
>Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055
>

Not even in sub panels!  The only place the neutral should be connected to the
ground is in a SERVICE DISCONNECT!  In your house the "main" panel serves as
the service disconnect.  Sub panles in your garage or workshop for example must
maintain seperate neutral and ground busses because they are not  service
disconnect equipment.


Steve Woodard, KD2KQ - not a licensed electrician, but I can read the NEC book.
                       (my brother is though)  :)
 

Newsgroup: sci.electronics
Document_id: 53617
Subject: Re: Exploding TV!
From: xhan@uceng.uc.edu (Xiaoping Han)

In article <1qk4hj$qos@vtserf.cc.vt.edu> prasad@vtaix.cc.vt.edu (Prasad Ramakrishna) writes:

>... Why would the picture tube explode or even smoke?

It's not the picture tube. More likely the flyback. Emerson? can't admire.
Han

>Prasad
>prasadr@vtvm1.cc.vt.edu
>



Newsgroup: sci.electronics
Document_id: 53618
From: hooperw@spot.Colorado.EDU (Wayne Hooper)
Subject: Re: making copy of a Video tape

victor@inqmind.bison.mb.ca (Victor Laking) writes:

>You are experiencing what is called Macrovision.  It is the protection 
>that they use on the video tapes.  There are two ways around this that I 
>know of.  First of all, you can try using a different VCR to copy onto.
>It is the input of the VCR that reacts to the protection so sometimes 
>just switching the two VCRs around will take care of it.  Some models 
>just don't react to it.

Does this also affect the viewing of tapes ? I have had problems with
a couple of rented tapes; they were virtually unviewable. I fiddled 
with the tuning, tracking and vertical hold but it was no good.


Newsgroup: sci.electronics
Document_id: 53619
From: lperez@decserv2.eecs.wsu.edu (Luis G. Perez)
Subject: Re: BEAM Robot Olympic Games next Week in Toronto.


Does anybody know if there is a mailing list or newsgroup for
Power Systems and related areas?

Thanks,

--
Luis G. Perez
lperez@eecs.wsu.edu


Newsgroup: sci.electronics
Document_id: 53620
From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Subject: Re: what to do with old 256k SIMMs?

 jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>	I was wondering if people had any good uses for old
>256k SIMMs...  So, if you have an inovative use (or want to buy
>some SIMMs  8-) ), I would be very interested in hearing
>about it.

About a month ago there was a photo posted on
alt.binaries.pictures.misc of a 17.5-inch Northern Pike which had been
caught on a lure made of 256K SIMMs.

-- 
----------------------------------------------------
Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
Vote straight ticket Procrastination party Dec. 3rd!

Newsgroup: sci.electronics
Document_id: 53621
From: heuvel@neptune.iex.com (Ted Van Den Heuvel)
Subject: Motorola MC14315 and MC143120 


Let me try sending this message again, I botched up the margins the
first time; *sorry* 'bout that :)

Does anyone out there know of any products using Motorola's Neuron(r)
chips MC143150 or MC143120. If so, what are they and are they utilizing
Standard Network Variable Types (SNVT)?
________________________________________________________________________

Ted Van Den Heuvel   heuvel@neptune.iex.com
KX5P
________________________________________________________________________

Newsgroup: sci.electronics
Document_id: 53622
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Trace size for a 15 Amp supply

acollins@uclink.berkeley.edu (Andy Collins) writes:

>How thick do I need to make a PCB trace for 15 Amps of current? and
>Does anybody have any other thoughts on the process (what kind of PCB
>to use, materials, thickness of copper, any advice graciously accepted)?

In four replies, I've seen no hard numbers, so here goes:  For traces
on the outside (not inner layers), expect, in 1 oz copper, at 15 amps,
the following temperature rises versus width.  This is from Sams'
"Reference Data for Engineers," seventh edition, Pg 5-30, which claims
in turn to be from MIL-STD-275C...

    width   Temp rise
    inches  degrees C
    ------  ---------
     .125	100
     .15	 75
     .17	 60
     .20	 45
     .24	 30
     .33	 20

At 10 amps, the rise for the .125 width is only about 30 degrees.
Power goes as square of the current, plus the copper resistance goes
up as temperature goes up...  Certainly .20" (~5mm) traces should be 
ample for what you want to do.  And 2 ounce copper almost cuts the 
required width in half.  (I'd do 2 oz at about 0.08" width myself, 
I think...given that the _rated_ current is 10 amps and the 15 is
a transient or fault condition.)

(There's another question: will the voltage drop be low enough?
But you should be able to figure this one out with wire tables or
just the resistivity of copper.  Keep traces short and use separate
sensing traces where appropriate, as mentioned by another poster.)

Newsgroup: sci.electronics
Document_id: 53623
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: Looking for 900MHz Spread Spectrum Modules

butts@shocker.ee.twsu.edu (Ronald W. Butts, Jr.) writes:

>I am looking for suppliers of 900MHz spread spectrum radio modules. I need 
>to implement a two-way audio band link (essentially the guts of a cordless 
>900MHz phone is what I want.)

This isn't exactly audio, but take a look in "RF Design" magazine,
April 93, for the article "A Robust Signaling Technique for Part 15
RF Control Netowrk Applications."  Page 29.  Sources of parts are
mentioned; in the same issue is an article that features a chipset
for the Digital European Cordless Telecommunications standard.


Newsgroup: sci.electronics
Document_id: 53624
From: tomb@hplsla.hp.com (Tom Bruhns)
Subject: Re: A question about 120VAC outlet wiring..

crisp@ecsvax.uncecs.edu (Russ Crisp) writes:

>SO..  Here's my question.  It seems to me that I'd have the
>same electrical circuit if I hooked a jumper from the neutral
>over to the ground screw on new 'three prong' grounding outlets.
>What's wrong with my reasoning here?  

May I respectfully suggest you NOT do this??  The ground is
supposed to be a protective ground, and though what you suggest
looks good on paper, it's dangerous to rely on the same wire for
power and protection.  It'd never meet code, and if you now own
the property and later sell it, you may end up with liabilities
you don't want, and if you _don't_ now own it, well...

There's a "wiring" FAQ that I think addresses this.  I believe
an alternative is use of a GFCI, but I'm really not sure what
current code allows in this area.  The GFCI senses alternate
(unwanted) current paths, and doesn't rely on a specific
protective ground wire, at least not beyond the GFCI in the
protected circuit.  GFCI breakers are available (but expensive).


Newsgroup: sci.electronics
Document_id: 53625
From: glenne@sr.hp.com (Glenn Elmore)
Subject: Re: Single chip receiver for FSK?

John Ackermann x 2966 (jra@law7.DaytonOH.NCR.COM) wrote:
: My next project is to come up with an IF/detector module for fast -- 112
: to 250 kB/sec -- packet radio use.  No fancy modulation scheme, just
: wide FSK for use at 902 or 1296 MHz.

: I'm a bit familiar with the Motorola 3362 chip, but I wonder if there
: are newer designs that might work at higher input frequencies.

: My goal is to come up with an inexpensive design for a receiver "back
: end" with IF input on one end and an FSK demondulator on the other.  I'm
: particularly interested in ways to use a higher IF than 10.7 -- do any
: current chips work up to, say 150MHz with internal downconversion so a
: normal IF filter can be used?

: Any suggestions?

: John

  What you describe is very close to what I built and described in the
10th ARRL Computer Network Conference proceedings.

  I built 10 watt FSK transceivers at 904 MHz.  They are essentially
double conversion transverters with digital mod and demod at 29 MHz.
The receiver uses the MC13055 which is the same FSK receiver chip I used
previouslyu in the 2 Mbps 10 GHz data link I first published in Ham
Radio and which is now also in the ARRL handbook.

  The MC3356, which includes a VHF converter section, could also be used
at these speeds.  There is a newer and perhaps slightly improved design
of this (the MC13056 if I remember rightly).

  While using this would have let me reduce the "external" IF count on
receive, it didn't really offer all that much help on transmit so I
didn't bother with it.

  The radios I built were first designed and built for 512 kbps in a 2
MHz channel but later reduced to half that.  These 256 kbps radios
actually have done quite well in across-the-bench tests at 384 kbps and
speed is pretty much a function of filter design.  Handling the data
stream is another matter entirely.

  Some of the existing radios are currently deployed on hilltops in a
"beacon" test mode.  While there is not yet end-end two-way data flow
due to lack of resources to debug software for the digital hardware (MIO
also shown in the CNC proceedings), data is perfect copy at n6gn.  Even
though the data clock is currently at about half speed, the a 2+ kbytes
of the test text (chapter 55 of Isaiah) takes only a little over 1/8 of
a second.

  I've been hoping that someone would get interested enough to step in
and get involved in writing code to make the whole thing usable (Borland
IDE environment with remote debugging possible as mentioned in the
proceedings) but to date a couple of us have been on our own and running
low on resources of time, money and energy.

  If anyone in the SF bay area wants to check it out there is also a CW
ID after the text on the mark side at 904.740 MHz from beacons on Sonoma
Mtn and Black Mtn (overlooking Si valley).  The antenna is horizontally
polarized.

  I guess in retrospect my suggestions are that this is a fairly costly
approach if the radios are intended for users rather than backbones and
you might want to carefully consider your "target".  If you can't
arrange your paths such that you have complete line-of-sight I think
you'll want to address the inter-symbol-interference caused by
multipath and probably link C/N budgets if paths are very far from LOS.
For more details, see the 10th CNC.  I'm currently working on a spread
spectrum, direct conversion design to address some of these problems.
I'd be glad to help as I can with any design problems.

73
Glenn Elmore n6gn

N6GN @ K3MC      
amateur IP:	glenn@SantaRosa.ampr.org
Internet:	glenne@sr.hp.com 



Newsgroup: sci.electronics
Document_id: 53626
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: TDR plug-in

I have an HP 1815 TDR plug-in for an HP180 series scope or mainframe
that I'm never going to use (no scope any more). If you're interested
in it, please let me know. Price? Probably real cheap.

This notice may have appeared once before. I posted, and it never showed
up on our local server...

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 53627
From: shanlps@ducvax.auburn.edu
Subject: TV RECEPTION:  HEELLLPPP!!!

Hello,

I just canceled my support of the Cable Regime and I would like to at
least pick up the 3 networks and NBC.  :)   I do not have tons of
money nor even a few pounds so what I am looking for is the best solution
for reception for under 100 dollars.  I have seen modules that you plug
into your wall outlet that "supposedly" make your entire house an
antenna.  I have to admit, even with my limited knowledge of wavelength
and aerial reception, this seems dubious in its claims for "excellent
reception" at best.  I'll try anything, though, if it WORKS.  I am in
a non-mountainous area, approximately 50 miles from the transmitting stations
which are pretty large (Montgomery Alabama pop. 200,000) and Colombus Goergia,
pop. 100,000+.  Any recommendations of products, brand-names, prices and 
company info (catalog ordering numbers, addresses etc.)?  Thank you in
advance.

Paul Sylvester Shanley   pshanley@humsci.auburn.edu   VOICE 205 887 7440


Newsgroup: sci.electronics
Document_id: 53628
From: ddr@flux.isr.alaska.edu (Donald D Rice)
Subject: Heavy-duty antenna simulation software


I would be interested in hearing from anyone who knows of good software for
antenna simulation, particularly in source form suitable for Unix workstations
(though good PC software would also be of interest).
I'm aware of the numerous mininec mutations, and have been using MN for
some time now.  I'm primarily interested in HF, VHF, and low UHF (< 500 MHz)
designs, mostly wire antennas, but for thick wires and mesh surfaces as well
as for your basic thin wire assumption.
Is anything interesting happening with NEC itself?  I've seen a version
that was mutilated to run (sort of) under Microsoft Fortran, but I'm not
sure how many "new and improved" versions of the code might be out there
somewhere.
I'd also be interested in non-NEC derivatives.  The ones I've seen have
been aimed at microwave applications, but if there is something out there
useful at the lower frequencies, I'd like to know about it.
Thanks,
-- 
Don Rice                   E-mail: ddr@flux.isr.alaska.edu    (Internet)
Geophysical Institute              fnddr@alaska               (BITNET)
University of Alaska               flux::ddr                  (SPAN)
Fairbanks, AK 99775        Phone:  (907) 474-7569        Loran: 64.86N 212.16E

Newsgroup: sci.electronics
Document_id: 53629
From: alung@megatest.com (Aaron Lung)
Subject: Re: IC Packages

In article <1993Apr16.142715.12613@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for some help in choosing a package
>for a high-speed silicon ADC (100Mhz) currently being 
>fabricated. This is a PhD research project and I have to test
>the chip at speed on a PCB. I expect to have roughly 100
>packaged circuits and will do DC, low-speed and high-speed
>testing using 3 different set-ups for the test chip.
> 	
>	I know for sure that a DIP will not work
>(the long lead lines have too high an inductance).
>Getting a custom-made package is too expensive, so
>I am trying to choose between a flatpak and a
>leadless chip carrier. The flatpack would be hard
>to test since it has to be soldered on to the test
>setup and I would spend loads of time soldering 
>as I kept changing the test chip. The leadless chip
>carrier sockets also have long lead lines and may
>not work at high speeds.
> 
>	Does anyone out there have experience/knowledge
>of this field ? I would greatly appreciate help! Any ideas/
>names of companies manufacturing holders/sockets/packages
>would help. 
> 
>P.S. The multi-layer fancy GaAs packages seem like a bit
>of overkill(?)
>	
> --- Seema Varma


You didn't mention whether or not cost is an issue.  Where
exactly are you running 100MHz??  THe digital side?  TTL?
ECL?  We run 200MHz and 100MHz all over our IC test equipment 
all day long in the ECL domain, and we use DIP's along
with PLCC's, 25mil and 20mil pitch 256pin QFP's to name
a few.  I don't see a problem in packaging as long
as you adhere to sound engineering practices.  

A good source of information is Motorola's MECL System Design
Handbook. The latest ed. is dated 2/88.  That is considered
to be one of the *bibles* in high-speed design.

The very fact that you need to build a test fixture means
you're most likely going to need a socket.  It in itself
has far more inductance per pin than the package you are
testing, not to mention any impedance discontinuities.  I
don't see the big concern over the packaging because it
probably isn't going to make that much difference

If you're trying to get TTL to run at 100MHz, have fun...
TTL was never designed to run in a 100MHz environment.
:-(

aaron

P.S. My opinions have nothing to do with my company...the
standard disclaimer applies.

Newsgroup: sci.electronics
Document_id: 53630
From: alung@megatest.com (Aaron Lung)
Subject: Re: Adcom cheap products?

In article <1993Apr16.105738.20864@hippo.ru.ac.za> webb@itu1 (90-29265  Webber  AH) writes:
> ...stuff deleted...
>
>I was also sceptical about the amps being built in the far-east
>  or where-ever.  But if you look in the amp and see what components
>  they use and how it was designed, you can easily see why the
>  amplifiers sound so brilliant.

Good point...also, I wouldn't be surprised that the components
they use off-shore are of inferior quality.  As long as it was
properly designed and robust, premium components are used, it
shouldn't matter where it is assembled.

>I cannot see why people say the amplifier won't last - not with
>  those quality components inside.  Sure the amp runs very fairly
>  hot - but that's how you get an amp to sound incredibly good.

An amp that runs hot has no bearing on how it's gonna sound.
The amp you have probably is running Class-A the whole day.

Actually, I'd be wary of excessively hot amps, 'cauz even though
the components inside may be rated to run that way, excessive 
heat will dramatically shorten the life of *any* electronic component
regardless of quality.  In fact, an amp that does run hot to the touch is
because either the engineer or manufacturer of that amp wanted
to skimp on heatsinking or cooling to save costs!  Hmmmmm....

aaron

.

Newsgroup: sci.electronics
Document_id: 53631
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <C5L5x0.KJ7@vcd.hp.com> johne@vcd.hp.com (John Eaton) writes:
>-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:

>During the nuclear fission reaction the uranium fuel can get hot enough
>to melt. When this happens the liquid uranium is pumped to the cooling
>tower where it is sprayed into the air. 

	Nonsense.  First, the uranium fuel is sealed in zirconium
alloy cylinders (which don't melt in any circumstances short of 
major failure of the power plant).  Second, the primary water
(that circulates inside the reactor core) is never pumped into the
cooling tower (it's the SECONDARY water cycle that goes 
through the cooling tower).  Third, liquid uranium would burst
into flame on contact with air.

>Contact with the cool outside air
>will condense the mist and it will fall back to the cooling tower floor.
>There it is collected by a cleaning crew using shop vacs and is then
>reformed into pellets for reactor use the next day.

	Cleaning crew working in a mist of uranium?  This is a
toxic heavy metal, even if it WEREN'T radioactive.  Shouldn't there
be some smileys here?  Or frowneys? 

	John Whitmore

Newsgroup: sci.electronics
Document_id: 53632
From: rsf@cbnewsb.cb.att.com (roberto.s.freire)
Subject: Fluke Scopemeter

Has anybody out there used/tested these new Fluke Scopemeters?
How do they compare to a low-end Tectronix oscilloscope? Are
there any big drawbacks about these handheld scopes when
compared to the benchtop scopes of the same price range
($1000-$2000)?

Any info on the Fluke Scopemeters would be greatly appreciated.

Thanks,

Bob Freire
rsf@houxa.att.com



Newsgroup: sci.electronics
Document_id: 53633
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: TV RECEPTION:  HEELLLPPP!!!

At 50 miles, a conventional set of TV antennas on a pole (one aimed
at each transmitter location) should work well.

"Rabbit ears" inside the house are probably not adequate.

Gadgets to plug into your house wiring are even worse.
At VHF, you don't want a _big_ antenna, you want a _resonant_
antenna.  

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53634
From: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
Subject: Optoisolator interfacing questions


I am interfacing some simple circuits that run on 9V to my
cpu board which runs at 5-6V.  The optoisolator is a 4N35.
On the led side, I put the signal I want through a 10k resistor
to the base of a 2N2222.  On the transistor side, I tie my
cpu input line to the collector which has a pull-up resistor
of 47k.

It functions OK, but seems VERY slow.  I can detect pulses
that occur at about 2kHz, but not much faster.  Isn't the
rise/fall time of this device, something like 5uS?  I should
be able to detect my target of 40kHz, but I can't get 16kHz.
This is done using wire-wrap and the wires going to the cpu
and to the test pin are about 8 inches long, but I'm not
doing anything high-speed.

In the Art of Electronics, it mentions tying the base of the
phototransistor to ground through a resistor to improve the
speed.  Is that what I need to do?  How do I calculate the
resistor value?


-- 

Paul Malenfant
pmalenfa @ kitkat.webo.dg.com (508-870-6460)

Newsgroup: sci.electronics
Document_id: 53635
From: segal@rtsg.mot.com (Gary Segal)
Subject: Pinout needed for TIL311

I've recently picked up some TIL311 display chips, but I can't find
any information on them.  It seems they are no longer made by TI, and
I don't have an old enough data book.  :-(

It appears to have a dot-matrix led display capable of showing one hex
digit.  It is in a 14 pin DIP package, but pins 6, 9, and 11 are not
present.

If you have any information on this part (pinout, power requirments,
functions, ...) please send me e-mail.

Thank You,

-- 
Gary Segal                             Motorola Inc.            
segal@oscar.rtsg.mot.com               Cellular Infrastructure Division
	--- we are standing here only to gaze at the wind ---

Newsgroup: sci.electronics
Document_id: 53636
From: martinkm@leland.Stanford.EDU (Kenneth michael Martin)
Subject: PADS model of a 68hc11.

Has anyone done a model of the 52 pin version of the 68hc11?  It doesn't
seem to be too big a job, but if someone else has already done it ...

many thanks
Ken Martin

Newsgroup: sci.electronics
Document_id: 53637
From: jeh@cmkrnl.com
Subject: Re: Need help with car stereo....

In article <1qih53$9ho@usenet.INS.CWRU.Edu>, ae454@cleveland.Freenet.Edu
 (Paul Simundza) writes:
> My friend has a nice Alpine car stereo, and it only has 2 channels,
> but one of them does not work. It does not put out any current or voltage
> at all, is that channel therefore blown?  I then shut the radio off and
> ran continuity into the two speaker ouputs of the channel, and it charged
> and discharged so I know the wires just aint bad.... 

This probably only tells you that the DC blocking capacitor that's in series
between the one-chip, single-ended audio amp and the speaker terminal is there.

> any Ideas? 

Open it up and look for the power amp "ICs".  They'll be fairly obvious. 
Replace the one connected to the dead output. 

> also,
> how would I locate where the signal of the radio/tape unit is BEFORE it
> gets amplified, because then couldn't I hook up RCA outputs to that signal
> so then he could just use a little amplifier? 

Well, one thing you should do is poke around the terminals of the power amp
chips.  Use a probe with a 10M resistor (like a scope probe) connected to the
input of a small audio amp w/speaker.  If you find line-level input to both
chips, one of the chips is bad and can probably replaced pretty easily.  

If you want to pick off a near-line-level signal, suitable for feeding to an
outboard amp, the outer legs of the volume control pot will often be good
enough.  This is *before* the volume control (and usually before the tone and
balance controls too).  If you take off from the center and ground legs of
the volume pot, this will be after the volume control (but again, probably 
before the other controls).  

If the unit is a modern type with an electronic volume control chip, you should
probably forget the whole thing. 

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
Document_id: 53638
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Anyone know about DATA I/O device proggers ?

I keep finding these programmers in local junk shops. This may
mean that they are indeed junk - but i'd like to hear from anyone 
else that may have met up with them. The basic device is a
"Data I/O 29A universal programmer", and the usual pod is a 
"LogicPak 303A-Vo4" with a "303A-001" programming tester/
adapter. I'd really like to hear from anyone who knows whether
these monsters are worth bothering with. All i want to do is blast
PALCE22V10s. - Ideas, folks
Mike.

Newsgroup: sci.electronics
Document_id: 53639
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: History question

Others said:
{early PA?}
# I recall reading of a phonograph which used mechanical amplification.
# Compressed air was squirted out of a valve which was controlled by the
# pickup.  The result was noisy and distinctly lo-fi, but much louder
# than a conventional phonograph.  It tended to wear the disks out
# pretty quickly though.

An now-deceased prof told us willing students about a project he had
worked on during WWII.

They needed a mega-power PA with very clear audio quality. The purpose
was to bellow at refugees from aircraft.

Their solution was a giant compressed-air source, and a horn with
parallel shutters worked by a small audio system. I think he said it
worked very well, thus the War Dept. cancelled the project ;_}.


--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
Document_id: 53640
From: ankleand@mtl.mit.edu (Andrew Karanicolas)
Subject: Re: IC Packages

In article <1993Apr16.142715.12613@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Getting a custom-made package is too expensive, so
>I am trying to choose between a flatpak and a
>leadless chip carrier. The flatpack would be hard
>to test since it has to be soldered on to the test
>setup and I would spend loads of time soldering 
>as I kept changing the test chip. The leadless chip
>carrier sockets also have long lead lines and may
>not work at high speeds.
> 
>	Does anyone out there have experience/knowledge
>of this field ? I would greatly appreciate help! Any ideas/
>names of companies manufacturing holders/sockets/packages
>would help. 

Check with Kyocera America, Inc.
           24 Prime Park Way, Suite 150
           Natick, MA 01760

They are one of the largest manufacturers of IC packaging in the
world.

It sounds like you would be a good candidate for wafer probing or at
least IC probing to test performance.  HP, Cascade Microtech and
Tektronix should be able to help you here.  One note, testing at high
frequency accurately can be an *expensive* business.

-- 
Andrew Karanicolas
MIT Microsystems Technology Laboratory
ankleand@mtl.mit.edu

Newsgroup: sci.electronics
Document_id: 53641
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: Exploding TV!

Others said:
# >... Why would the picture tube explode or even smoke?

Naw, it was the penguin on TOP of the set that exploded...
;-}

--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
Document_id: 53642
From: lzahas@acs2.bu.edu (Lukas Zahas)
Subject: Re: How do DI boxes work?

In article <LANCER.93Apr15150228@oconnor.WPI.EDU> lancer@oconnor.WPI.EDU (Stephe Lewis Foskett) writes:
>
>I'm doing sound for a couple of bands around here and we need Direct
>Input boxes for the keyboards.  These are the little boxes that take a
>line level out of the keyboard and transform it into low-Z for the run
>to the mixer.  Sadly they cost like $50 (or more) each and I'm going
>to need like 5 or 10 of them!  I looked inside one (belonging to
>another band) and it looks like just a transformer.  Does anyone have
>any plans for building them?  
>
$50 each!!  Don't bother trying to make one yourself, just shop around a
little.  I've found DOD brand DI boxes for as cheap as $20 each.  You can 
get higher end ones for more, but for PA use for bands, I wouldn't bother.
Making one yourself might work, but getting a sturdy enough enclosure might
be hard (they're made of heavy guage metal, since they're always on the floor,
being kicked around a lot). For any additional questions on this topic, you 
might want to post to rec.audio.pro
						Lukas Zahas
						lzahas@bu.edu

Newsgroup: sci.electronics
Document_id: 53643
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Radio Shack voice recognition chips

Hi there,

I have a friend who'd like to get a hold of a bunch of those simple voice
recognition chips that Radio Shack used to sell (and no longer does).  If
anybody knows of a source for these, please e-mail me.  I'll forward the
responses to him.

Thanks!

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 53644
From: Mark-Tarbell@suite.com
Subject: Switch-mode power supply

Is there a typical component or set of components
that are at fault when a switch mode power supply 
goes south?

The supply is for a disk drive. Any general hints
would be appreciated!

Thanks!
Mark-Tarbell@suite.com
at fault when a switch mode power supply 
goes south?

The supply is for a disk drive. Any general hints
would be appreciated!

Thanks!
Mark-Tarbell@s$$BVh(J

Newsgroup: sci.electronics
Document_id: 53645
From: rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter)
Subject: Re: Can Microwaves Be Used To Collect XYZ Coordinates

Where can you get info (brochures...) on Differential GPS Systems and where to 
buy them?

BobC



Newsgroup: sci.electronics
Document_id: 53646
From: psgwe01@sdc.boeing.com (Gerald Edgar)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In making batteries you could use copper and zinc in an acid electrolyte.     
Copper=copper wire (pennies are now mostly zinc if I recall correctly)
zinc= zinc strip (Hardware stores arround here (Seattle) sell this to prevent
      moss buildup on the roof. An alternative would be to use a galvanized
      (zinc coated) nail
electrolyte= lemon juice -> Citric acid is the active ingrediant(sp).
 
Volta (late 18th century scientist) used a stack for his batteries-
copper disk, paper disk soaked in acid, zinc disk, copper disk, paper ....
they were advanced technology for the time. 
 
Gerald Edgar
gwe3409@atc.boeing.com
"The opinions expressed in this communication may not reflect those of my
employer"

Newsgroup: sci.electronics
Document_id: 53647
From: st1my@rosie.uh.edu (Stich, Christian E.)
Subject: Motorola XC68882RC33 and RC50

I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
68030 + 68882 with capability to clock the FPU separately).  Previously
a MC68882RC25 was installed and everything was working perfectly.  Now the
systems displays a yellow screen (indicating a exception) when it check for
the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
fine, but with the XC68882 even at 25 MHz it does not work.  The designer
of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
might help, but that didn't change anything.  Does anybody have some
suggestions what I could do?  Does this look like a CPU-FPU communications
problem or is the particular chip dead (it is a pull, not new)?
Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
Are there any MC68882RC33?

Thanks
	Christian 


Newsgroup: sci.electronics
Document_id: 53648
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Telephone On Hook/Off Hok

AllMichael CovingtonTelephone on hook/off hok

MC>From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
MC>Organization: AI Programs, University of Georgia, Athens
MC>Aye, there's the rub -- if you draw enough current to light an LED, th
MC>equipment at the phone company will think you've gone off hook.
MC>In the on-hook state you're not supposed to draw current.  

Ok lets have some calculation here: Going by Australian standards, which I 
presume might be similar to other countries ( If not, lets have some 
input) a phone uses 600ohm to loop a 48V line = 80mA. A standard LED 
drains 20mA. So what is the actual loop current required for an "off hook" 
indication, do you know?

Cheers 
Peter T.


Newsgroup: sci.electronics
Document_id: 53649
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: What'S A Good Ic For Rs23

AllTall Cool OneWhat's a good IC for RS23

TC>From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
TC>Organization: University of Illinois at Urbana
TC>I'm looking for an IC that will convert RS232 voltage levels to TTL vo
TC>levels.  Something relatively inexpensive would be nice, too.  Anyone 
TC>a suggestion??  Thanks.

Try a Maxim "MAX232CPE" 8 pin dil, converts 5V to 12V for 232commms.
What a clever little gizmo!

Peter T.


Newsgroup: sci.electronics
Document_id: 53650
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Swr Meter For Cb Radios

AllThe Devil ReincarnateSWR meter for CB radios

TD>From: ssave@ole.cdac.com (The Devil Reincarnate)
TD>Organization: CDAC, WA
TD>What
TD>is a good choice for a CB? 1/4 or 1/8 wave?
TD>  I read the installation instructions on a 1/4 wave antenna,
TD>and they suggested that I use an SWR to tune it at channel 12
TD>and channel 32 for a minimum reading.  Question is, why channel
TD>12 and 32?

The best antenna is one that will let out the most wave (probably not the 
best explanation, but the rest makes sense) A one wave will cancell itself 
out (BTW no such beastie) . The best is a 1/2 wave antenna, followed by 
1/4, then 1/8 etc.

As for SWRing in, what you actually do is trim the antenna to the correct 
length for the specific wavelength you will be transmitting on. Since the 
wavelength varies with the channel you use, then it's recommended to SWR 
in using the middle channel of those you are going to use.
Anyway in the beginning of CB's, all new antennas had to be SWR'ed in, 
nowdays manufactures trim the antennas almost spot on, so that there's not 
much point in SWRing. Then again you may be a fanatic and whish to do it 
anyway.

Cheers 
Peter T.


Newsgroup: sci.electronics
Document_id: 53651
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: What'S Exactly In A Flour

AllMartin MccormickWhat's Exactly in a Flour

MM>From: martin@datacomm.ucc.okstate.edu (Martin McCormick)
MM>Organization: Oklahoma State University, Stillwater, OK
MM>	What sort of lamp is the little glass bulb found inside the 
starter?
MM>It sort of reminds me of a NE2 neon lamp.  Starters appear open when m
MM>with an Ohm meter so the little lamp is either a neon or has a capacit
MM>in series with it.
MM> 
MM>	I have seen these things all my life, but never read a really good
MM>description of what is happening inside that little can.

Do you know what a bi-metallic strip is?
Just in case: it is two strips of different metals bonded together, which 
when heated bend to one side (check out the blinker globe in your 
christmas tree lights).

So when you turn on the power, this causes the bulb to work like a neon, 
heating up and shorting out, thus providing a loop to power the heaters in 
the main tube. When the tube fires, insufficient current runs through the 
starter to keep the heat up and the bi-metalic strip straightens out 
(O/C).

BTW, I too thought that they were nothing more than a small neon, so one 
day when the neon in my sisters digital (flip the metal squares type) 
clock broke (flimsy leads), I replaced it with one from a starter. Well 
powering up made a bit of a mess of the clock!

Cheers
Peter T.   


Newsgroup: sci.electronics
Document_id: 53652
From: peter.m@insane.apana.org.au (Peter Tryndoch)
Subject: Dmm Advice Needed

AllMartin EmdeDMM Advice Needed

ME>From: mce5921@bcstec.ca.boeing.com (Martin Emde)
ME>Organization: Boeing
ME> 
ME>I an currely in the market for a DMM and recently saw an add
ME>for a Kelvin 94 ($199).  Does anyone own one of these or some
ME>other brand that they are extremely happy with.  How do the 
ME>small name brands compare with the Fluke and Beckman brands?
ME>I am willing to spend ~$200 for one.
ME> 
ME>Any help is greatly appreciated. (please email)
ME> 
ME>-Martin

If you are going to use one where it counts (eg:aviation, space scuttle, 
etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
for every other use you can buy a cheapie. I have a metex which is some 
made up name, as I have seen the same DMM with other brand names on it, I 
bought it about 4 yrs ago for Aus$125.00 (convert that to US and you see 
that it's definetly a cheapie.) So far it has proved to be accurate, taken 
moderate abuse, and has many features on it (CAP, FREQ,Transistor check, 
etc). I am very happy with it and would definetly not buy a fluke just for 
the name. Hope this helps.

Cheers 
Peter T.


Newsgroup: sci.electronics
Document_id: 53653
From: R_Tim_Coslet@cup.portal.com
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
	swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
>I really don't know where to post this question so I figured that
>this board would be most appropriate.
>I was wondering about those massive concrete cylinders that
>are ever present at nuclear poer sites. They look like cylinders
>that have been pinched in the middle. Does anybody know what the
>actual purpose of those things are?. I hear that they're called
>'Cooling Towers' but what the heck do they cool?

Except for their size, the cooling towers on nuclear power plants
are vertually identical in construction and operation to cooling
towers designed and built in the 1890's (a hundred years ago) for
coal fired power plants used for lighting and early electric railways.

Basicly, the cylindrical tower supports a rapid air draft when
its air is heated by hot water and/or steam circulating thru a network
of pipes that fill about the lower 1/3 of the tower. To assist cooling
and the draft, water misters are added that spray cold water over the
hot pipes. The cold water evaporates, removing the heat faster than
just air flow from the draft would and the resulting water vapor is
rapidly carried away by the draft. This produces the clouds frequently
seen rising out of these towers.

That slight pinch (maybe 2/3 of the way up the tower) is there because
it produces a very significant increase in the strength and rate of
the air draft produced, compared to a straight cylinder shape.

The towers are used to recondense the steam in the sealed steam
system of the power plant so that it can be recirculated back to the
boiler and used again. The wider the temperature difference across
the turbines used in the power plant the more effecient they are and
by recondensing the steam in the cooling towers before sending it
back to the boilers you maintain a very wide temperature difference
(sometimes as high as 1000 degrees or more from first stage "hot"
turbine to final stage "cold" turbine).

                                        R. Tim Coslet

Usenet: R_Tim_Coslet@cup.portal.com
        technology, n.  domesticated natural phenomena

Newsgroup: sci.electronics
Document_id: 53654
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Telephone On Hook/Off Hok

In article <734953838.AA00506@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:

>MC>Aye, there's the rub -- if you draw enough current to light an LED, th
>MC>equipment at the phone company will think you've gone off hook.
>MC>In the on-hook state you're not supposed to draw current.  
>
>Ok lets have some calculation here: Going by Australian standards, which I 
>presume might be similar to other countries ( If not, lets have some 
>input) a phone uses 600ohm to loop a 48V line = 80mA. A standard LED 
>drains 20mA. So what is the actual loop current required for an "off hook" 
>indication, do you know?

Up to 60 microamperes  =   on hook

Over something like 10 mA  = off hook

In between = defective line, and the phone company comes looking
              for leaky insulation.



-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53655
From: rmf@bpdsun1.uucp (Rob Finley)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


Intel also makes some neat memory and peripheral chips:

Old technology (early 1980's)  
8155  ram plus IO (slow ram as I recall)
8755  eprom plus IO (expensive and slow)


Intel does make Eproms with built in address latches.
I fear that you would need a very flexible and up-to-date eprom
programmer to write to them.

give them a call.  I am not able to locate their memory products book
yet.



Sigh...  Now, who borrowed it...

Robert



Newsgroup: sci.electronics
Document_id: 53656
From: haynes@cats.ucsc.edu (Jim Haynes)
Subject: Re: History question


In article <1qnroe$d1n@usenet.INS.CWRU.Edu> wb8foz@skybridge.scl.cwru.edu (David Lesher) writes:
>An now-deceased prof told us willing students about a project he had
>worked on during WWII.
>
>They needed a mega-power PA with very clear audio quality. The purpose
>was to bellow at refugees from aircraft.
>
>Their solution was a giant compressed-air source, and a horn with
>parallel shutters worked by a small audio system. I think he said it
>worked very well, thus the War Dept. cancelled the project ;_}.

Gee, I got the idea from somewhere that devices like this were in common
use in WWII, so that commanders on board ships could bellow at the troops
landing on a beach, for example.

Which reminds me of an anecdote from the mid-60s.  At a communications
conference a Marine Corps communications officer said he didn't care
much for all the spread-spectrum multi-access expensive communication
systems that people were talking about at the time; what he wanted
was a kilowatt broadcast transmitter on the ship and a $4.95 Japanese
transistor radio stuck in the ear of every Marine hitting the beach.
-- 
haynes@cats.ucsc.edu
haynes@cats.bitnet

"Ya can talk all ya wanna, but it's dif'rent than it was!"
"No it aint!  But ya gotta know the territory!"
        Meredith Willson: "The Music Man"


Newsgroup: sci.electronics
Document_id: 53657
From: gt0869a@prism.gatech.EDU (WATERS,CLYDE GORDON)
Subject: Re: History question

In article <2775@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:
>This is vague, so I am posting it in case anyone else knows more.
>
>I recall reading of a phonograph which used mechanical amplification.
>Compressed air was squirted out of a valve which was controlled by the
>pickup.  The result was noisy and distinctly lo-fi, but much louder


NASA and related agencies apparently used this same principles to create
the loudest reported reproduced sound. They used an "analog" electrically
controlled valve to control the flow of air across a horn throat. If I 
remember correctly it was called a "modulated air blast transducer". There
were reports of the thing being able to produce 106 dB @ 80 Hz @ 10 mile
distance, communicate directly with fighter pilots @ 5000 ft, etc.

Regards,
Gordon.

-- 
WATERS,CLYDE GORDON-BME '93-Georgia Institute of Technology Atlanta Ga. 
"Out of the mountain of despair, we can hew the stone of hope"- MLK Jr. 
uucp:	  ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0869a
Internet: gt0869a@prism.gatech.edu

Newsgroup: sci.electronics
Document_id: 53658
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: subliminal message flashing on TV

> Hi.  I was doing research on subliminal suggestion for a psychology
> paper, and I read that one researcher flashed hidden messages on the
> TV screen at 1/200ths of a second.  Is that possible?  I thought the
> maximum rate the TV was even capable of displaying images was 1/30th
> of a second.  (or 1/60th of a second for an image composed of only odd
> or even scan lines)

You are correct; the fastest "complete" image that could be presented on
TV would be one field, which is 1/60 of a second (approximately).  Of course,
the phrase "TV screen" is often thrown around in reference to any CRT
display, so perhaps this researcher wasn't using normal TV rates.  Might
even be a vector ("strokewriter") display, in which case the lower limit
on image time is anyone's guess (and is probably phosphor-persistence limited).


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
Document_id: 53659
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Scope questions

> 	If my life depended on it, I'd say that it's a scope that
> 	uses long-persistance phosphor to keep the successive
> 	taces on the screen for some unit of time - "store" them.
> 	Do I get to live?

We'll let you live, but just this once....

There's more to a real "storage" scope than just a long-persistence
phosphor.  Actually, the phosphor ISN'T usually anything special at all;
what makes a storage tube work is a screen placed just *behind* the phosphor,
which becomes charged as the electron beam intially "writes" the trace.
With the trace now written to the screen, a separate low-level "flood"
electron gun keeps the image lit by exciting those areas of phosphor
which are next to the "written" areas on the storage screen.  There are
some problems with this - the resolution is limited compared to a non-storage
tube, and the stored trace tends to "bloom" with time. 

Of course, this is pretty much obsolete technology, done in by the current
digital scopes which use raster-scan displays and keep everything in a
frame-buffer memory anyways.

> / Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
          ^^^^^^^^^^^^^^^^^^

Ah, yes - from the same people who brought you that amazing new reading
program that's sweeping Eastern Europe: "Hooked on Consonants!" :-)


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
Document_id: 53660
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Dmm Advice Needed

In article <734953838.AA00510@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:
>
>If you are going to use one where it counts (eg:aviation, space scuttle, 
>etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
>for every other use you can buy a cheapie.

My Beckman died a few days ago, thanks do about a 4 or 5 foot drop onto a
lab table.  !@#!@$#!@$@#$  Probably not indicative of anything, but I've
already filled out the requisition for a Fluke 87. :-)

Oh yeah, and sometimes our measurements here do count.  Not often, but often
enough that I want at least _one_ good meter!

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 53661
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: What do Nuclear Site's Cooling Towers do?

Excerpts from netnews.sci.electronics: 16-Apr-93 Re: What do Nuclear
Site's .. by R_Tim_Coslet@cup.portal. 
> From: R_Tim_Coslet@cup.portal.com
> Subject: Re: What do Nuclear Site's Cooling Towers do?
> Date: Fri, 16 Apr 93 21:27:21 PDT
>  
> In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
>         swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
> >I really don't know where to post this question so I figured that
> >this board would be most appropriate.
> >I was wondering about those massive concrete cylinders that
> >are ever present at nuclear poer sites. They look like cylinders
> >that have been pinched in the middle. Does anybody know what the
> >actual purpose of those things are?. I hear that they're called
> >'Cooling Towers' but what the heck do they cool?
>  
> Except for their size, the cooling towers on nuclear power plants
> are vertually identical in construction and operation to cooling
> towers designed and built in the 1890's (a hundred years ago) for
> coal fired power plants used for lighting and early electric railways.
>  
> Basicly, the cylindrical tower supports a rapid air draft when
> its air is heated by hot water and/or steam circulating thru a network
> of pipes that fill about the lower 1/3 of the tower. To assist cooling
> and the draft, water misters are added that spray cold water over the
> hot pipes. The cold water evaporates, removing the heat faster than
> just air flow from the draft would and the resulting water vapor is
> rapidly carried away by the draft. This produces the clouds frequently
> seen rising out of these towers.
>  
> That slight pinch (maybe 2/3 of the way up the tower) is there because
> it produces a very significant increase in the strength and rate of
> the air draft produced, compared to a straight cylinder shape.
>  
> The towers are used to recondense the steam in the sealed steam
> system of the power plant so that it can be recirculated back to the
> boiler and used again. The wider the temperature difference across
> the turbines used in the power plant the more effecient they are and
> by recondensing the steam in the cooling towers before sending it
> back to the boilers you maintain a very wide temperature difference
> (sometimes as high as 1000 degrees or more from first stage "hot"
> turbine to final stage "cold" turbine).
>  
>                                         R. Tim Coslet
>  
> Usenet: R_Tim_Coslet@cup.portal.com
>         technology, n.  domesticated natural phenomena

Great Explaination, however you left off one detail, why do you always
see them at nuclear plants, but not always at fossil fuel plants.  At
nuclear plants it is prefered to run the water closed cycle, whereas
fossil fuel plants can in some cases get away with dumping the hot
water.  As I recall the water isn't as hot (thermodynamically) in many
fossil fuel plants, and of course there is less danger of radioactive
contamination.

Wayne Martin




Newsgroup: sci.electronics
Document_id: 53662
From: mvanmeet@ua.d.umn.edu (Mike VanMeeteren)
Subject: Re: electronic odometers (was: Used BMW Question ..... ???)

In article <C5HHKo.1ry@vu-vlsi.ee.vill.edu> mobasser@vu-vlsi.ee.vill.edu (Bijan Mobasseri) writes:
>> There are two simple procedures for alterating any odometer.
>>
>>1. Mechanical driven odometer:
>>    Remove the speedo cable from the transmission.
>>    Attach a drill and run at max speed until the speedo turns over.
>>    Continue until the desired mileage is reached.
>====================================
>Admittedly an irrelavent question:for how long should the drill be running?
>
>Bijan

A verrrrrry long time, like on the order of days.  I had the pleasure of
doing that once (playing with the speedo cable) and with my B&D heavy duty at
full speed (600 rpm) all the speedo ever got up to was 30 MPH.  Now if you go
a high speed drill and ran it at say 4000 rpm, you could get 200 MPH out of
it.  (If you speedo doesn't burn out.)  Anyways, to roll a 100000 Mile
odometer would take 22 days or so.  Much easier just to take the speedo
apart.

Thought I'd share.  BTW, all this info was obtained legally  :-)


-- 
(~)~)~) o /)  _     Computer Lesson One: There is no "any" key, alternate keys
 / / / / /_) /_)                         are <shift>,<ctrl>,<caps lock>,<alt>
/ / (_(_/ (_/\_                          and sometimes <tab>.
mvanmeet@ub.d.umn.edu                                -consultant at lab

Newsgroup: sci.electronics
Document_id: 53663
From: schmidt@auvax1.adelphi.edu
Subject: Grounding power wiring, was Re: a question about 120VAC outlet wiring

There has been quite a bit of discussion about house wiring and grounding
practices here.  A few points need to be clarified:

The Equipment GROUNDING conductor, Green, green with a yellow stripe, bare, or
the metal sheath or pipe of SOME wiring methods, is used as a safety ground, to
carry fault currents back to the circuit breaker panel, and to limit the
voltage on the metal case of utilization equipment or other metal objects.  It
should never (except for a few exceptions to be discussed later) carry the
normal operating current of a connected load.  Some equipment has filters in
the power supply which may cause some slight current flow through the grounding
conductor.  

Much communications or audio equipment is sensitive to noise or slight voltages
on the grounding conductor, and may require special wiring of the grounding
conductors to provide reliable operation  ("orange" outlets are often used for
this, with insulated grounding conductors wired back to the panel box, and in
many cases back to the service.  Anyone installing such a system should read
both the section on grounding in the National Electric Code and publications on
installing quiet isolated ground systems.  The code requires the insulated
grounding conductors (green wires) to run with the current carrying conductors
back to the panel box, and, if required, back all the way to the service
entrance , where it is bonded to the service ground (water pipe or rod)  Many
of these systems are installed illegally or unsafely, where they do not provide
a safe ground or a quiet ground or either. 

The GROUNDED conductor of a circuit, often called the NEUTRAL, which is
referred to in the code as the "identified" conductor and is supposed to be
white or natural grey.  This conductor is supposed to be connected to ground in
most electrical systems at a single point, generally at the service entrance
panel.  This connection is through the Main Bonding Jumper.  (In many household
service panels, the main bonding jumper is actually a bonding screw which
attaches the neutral busbar to the case of the panel)  

The Grounded conductor (neutral) is generally a current carrying conductor.  In
the case of a 120 volt circuit it is one of the two conductors completing the
circuit from the panel to the load device.  

Since the grounded conductor (neutral) is only connected to the grounding
conductor (bare or green) at the service entrance, if the load is any distance
from the service and draws any significant current, there will be a small but
measurable voltage between the grounded and grounding conductors at the load,
under normal operating conditions.  If you should (incorrectly) connect the
grounded (neutral) conductor to the grounding conductor at the load, some of
the neutral current will flow instead through the grounding conductor.  Since
there will now be current flowing through the grounding conductor, it will also
no longer be quite at ground potential at the load end.  If the load equipment
has a metal case, which is connected to the grounding conductor through the "U"
ground plug, the metal case is now also no longer quite at ground potential. 
The difference (under normal, non short-circuit conditions) may be only a few
tenths of a volt, but it could also be a volt or two.  This normally does not
present a shock hazard.  

HOWEVER, if you let the metal case of the grounded equipment come into contact
with an independently grounded object such as a water or gas pipe, a radiator,
a metal air conditioning duct or such, part of the neutral current will try to
flow through this aalternate ground path.  If the contact is not solid, you
will get a significant arc (a low voltage, but possibly moderate current arc)
Under the wrong conditions, this arcing could start a fire.  It is possible in
some cases that the sneak ground current   could also flow through a wire of
inadequate size, causing it to overheat.

With the incorrect non single-point grounding of the neutral, if there is a
short circuit from hot to neutral, the high short circuit current which may
flow will cause a much higher voltage on the grounding conductor, which
increases the possibility for shock or fire.  

Also if you incorrectly multiply connect the neutral and ground, the voltage on
the ground system is seen as noise bu computer or audio equipment, often
causing malfunction.  I have spent some hours tracking down such shorts in
technical facilities where they were inducing severe hum into equipment.

The Neutral is usually bonded to the ground at the distribution transformer as
well as at the service entrance of each dwelling.  This is done primarily for
lightning protection, so that induced lightning currents have a short path back
to ground, and also to assure that the currents drawn by shorts to grounded
objects like pipes draw enough current to trip circuit breakers or blow fuses
quickly.  The bad side of this is that not all the neutral current from the
dwelling goes through the neutral wire back to the transformer.  Some of it
flows through the grounding electrode (water pipe, etc.) this may cause
corrosion in the pipes and possibly in things like underground fuel oil tanks,
and it may also cause measurable AC magnetic fields due to the large loop
between the "hot" conductors in the service and the neutral current in the
water pipe and ground.  There are those who feel these fields may be unhealthy. 
(don't flame ME on this, I'm just telling you where the field comes from, not
it's health effect, as far as I'm concerned, the jury is still out on this.)

Note that the bonding jumper is only installed at the main panel, NOT at any
sub distribution panels.  This is one reason why it is illegal to run service
entrance cable with the sheath used as a neutral to a sub panel, you must have
a seperate insulated conductor for the neutral.  The sheath can be used in this
application only as the groundING conductor.  If the neutral is bonded to the
grounding conductor in the sub panel, say by forgetting to remove the bonding
screw, all the grounding conductors of the loads on that panel will be above
ground, with the possible problems listed above.

The code makes exceptions for ranges and dryers, as well as feeds from one
building to another.  In the cases of the range and dryer, the neutral may be
used as the equipment ground under certain conditions, instead of a seperate
wire.  Every time the code is revised, these exceptions come up for review. 
These exceptions were, in fact the first required safety grounds, in the days
before U ground outlets and such.  The appliance manufacturers don't want to
have to redesign their ranges and driers, and the contractors don't want to
have to run four wire cable (with four fairly heavy, expensive wires) in place
of three wire to the appliances.  No question it would be safer with seperate
neutrals to the stove, but the neutral current is low for most burner settings
(since most current is in the 220 volt "hots" except at some low settings, the
wires are large gauge, and there are few reported cases of injury or damage. 
So far, the exceptions have survived. In the case of feeds between buildings,
it's primarily for lightning protection.

People doing wiring should be aware what is and what isn't a legal grounding
conductor.  Obviously, the bare wire in "romex" 'with ground' is.  Anywhere
there is a green wire installed, such as in a portable cord, that is a good
grounding conductor.  The sheath of BX clamped in BX connectors in metal boxes
is a legal grounding conductor (in the US). (BX has an aluminum band run under
the steel sheath to lower the resistance of the sheath.  You can just cut this
aluminum band off at the ends, you don't have to bond it to anything, it does
its job by touching every turn of the BX sheath.) Conduit or EMT (thinwall
tubing) is generally a legal grounding conductor, but may require a bonding
locknut where it enters a box or panel, particularly for larger pipes.  

"Greenfield" (looks like big BX, but you pull your own wires in the empty
sheath after you run it) is NOT a legal grounding conductor, as it doesn't have
the aluminum band to bond it, and the spiral steel has too much resistance and
inductance.  You have to run a seperate green grounding conductor inside the
greenfield.

"Wiremold" is also not a legal grounding conductor, as the paint on the boxes
often prevents good contact, and the "feed" to the wiremold extension is often
from a box in the wall that may not be well connected to the first wiremold
box.  I have personally discovered cases where the entire run of wiremold and
the cases of everything plugged into all the outlets on the run were "hot" with
120 volts (Why do I get a shock every time I touch my computer and the radiator
here in the office?) because there was no ground wire in the wiremold and one
of the outlets had shorted to the edge of the wiremold box.  You must run a
ground wire back in the wiremold from the outlets at least to the first box in
the original wiring (conduit, BX, etc.) where you can "bond" the wire to the
box with a screw, bnding clip, or whatever.

On another issue, while you should ground the green wire/lug on GCFI outlets
when ever there is a place to ground them, it is legal in the NEC to use them
without a ground if no ground is available.  It is better to have the
protection of the Ground fault interrupter than no protection if you don't
install it.  The interrupter doesn't depend on the ground to trip.  It is
desirable to connect the ground if available, because if the ground is
connected, the interrupter will trip as soon as a faulty device is plugged in,
whereas without the ground, it will not trip until someone or something
provides a ground path.  For those questioning the legal use of ungrounded
GCFI's, read in the NEC, 210-7 (d) exception. (This is the 1990 code, my '93
code is in the city, but I know the rule hasn't changed.  It might be
renumbered though.) 

We have only touched the surface concerning grounding ;-} , there is much more
to this subject, but most of you have fallen asleep by now.  

John
-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218 
Adelphi University                 |       Evenings (516)877-6400 
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
Document_id: 53664
From: zklf0b@wwnv28.hou.amoco.com (Fergason)
Subject: Re: what to do with old 256k SIMMs?

In article <1ql7ug$i50@sunb.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
>In article <120466@netnews.upenn.edu>, jhaines@eniac.seas.upenn.edu (Jason Haines) writes:
>|> 
>|> 	I was wondering if people had any good uses for old
>|> 256k SIMMs.  I have a bunch of them for the Apple Mac
>|> and I know lots of other people do to.  I have tried to
>|> sell them but have gotten NO interest.
>|> 
>|> 	So, if you have an inovative use (or want to buy
>|> some SIMMs  8-) ), I would be very interested in hearing
>|> about it.
>
>The most practical use I've seen for them is as key ring ornaments :-)
>
>JohnH

I used a bunch as weights, when building a model airplane.  Hung them
on the stringers, across the stringer, or whatever.  Worked pretty well.

Kelly


Newsgroup: sci.electronics
Document_id: 53665
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Can I use a CD4052 analog multiplexer for digital signal

> As the subject says - Can I use a 4052 for digital signals?  I don't see
> why it couldn't handle digital signals, but I could be wrong.  Anyone have
> any advice?  Thanks.

Yes.

I use 74HC4066 and others commerically for this purpose so rest assured it 
works fine. In one case I route bit serial digital audio using these and it 
is difficult to see any signal degradation at all which surprised me given 
some pretty fast edges. HC4066 is spec'd at something like -3dB @ 200MHz into 
50 ohms. The more complex types are generally a little slower and more 
resistive.

Plain 4000 series are not so good at handling 5v logic.

Remember that the output load is seen by the input device.

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
Document_id: 53666
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: Whats wrong with my cordlessphone?

I've also found that the electronic starters on these "instant-on" 
compact fluourescent lamp fixtures kick out interference that nukes
my cordless phone.  (I can hear it in my guitar amplifier, too...)
--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
Document_id: 53667
From: cs000rdw@selway.umt.edu (Richard D Warner)
Subject: UART-CPU-ROM-RAM subsystem

	This is a followup post to something I've written previously.  Several
people responded with good information, but I don't think I communicated 
exactly what I am looking for.
	I'm working on a custom I/O device that will communicate with a host
via RS-232.  My custom circuitry will use an 80C186EB or EC CPU and require
about 64K of RAM (preferably FLASH RAM).  In looking around, I see that lots
of people have engineered UART-CPU-ROM-RAM subsystems that are ready to be
interfaced to your custom I/O devices.  It's been done so much, that it 
would be best if I can avoid reinventing a system.  It just needs to use
an 80C186 (or 188) CPU, and be able to load a program from the host then 
transfer control to that program.  Well, there's one other thing the ROM
needs to know how to do.  It should have routines to send and receive bytes
to/from the host, that utilize the hardware control lines (DTR,RTS,DTS,CTS).
Everything I've seen is in the $200.00 and up range.  That's too much for
this application.  I need something around $100.00.  The CPU has the UART
built-in, so you're only looking at a few chips.  Does anyone know a 
company that markets a good board in this range, or some public domain 
circuitry I can use?  Thanks in advance for the info.

Rich


Newsgroup: sci.electronics
Document_id: 53668
From: ianmc@spartan.ac.BrockU.CA (Ian McPherson)
Subject: Re: chip / chipset for code 39 barcode?

LLBGB@utxdp.dp.utexas.edu wrote:
: Distribution: usa
: Reply-To: lihan@ccwf.cc.utexas.edu

: While I'm on the net bugging everyone, is there such a thing as a chip
: or chipset to decode Code 39 barcode?  I ask for a couple of reasons --
: mainly I want a reasonably compact encoding scheme to write information
: on magstripe cards and Code 39 appears to be about right.  (If the 'right'
: way to do it is something else, and it's reasonably easy, can someone let
: me know?)

: I might not get a chance to reply too quickly to this or my earlier post,
: but I'll get to them within a couple days, I think ..

: thanx everyone!  <BGB>  lihan@ccwf.cc.utexas.edu

Hewlett Packard has a series of barcode decoder ICs HBCR-1800, HBCR-2000,
and HBCR-2010 and they support 3of9  extended 3of9  interleaved 2of5  
and UPC codes. The 2000 and 2010 pieces add codabar and code 128.

These chips support HP's barcode wands and slot readers.

An 1800 + a HEDS-3050 wand run about $150 CDN .

Ian.


Newsgroup: sci.electronics
Document_id: 53669
From: rbn@apple.com (Robert B. Neville)
Subject: Oscilliscopes for sale

Recently I posted two oscilliscopes for sale. One has sold, the other is
still available:
 Used, good condition:
 Hitachi V-422 40MHz Dual-Channel Portable Analog Oscilliscope
   o 1mV/div
   o DC offset
   o alternate magnification (10x magnified & non-magnified
     waveform)
   o VERT mode trigger
   o TV sync separation circuit
 List price      $910.00 (...and the price Fry's electronics just
                         quoted!) :-(
 Sells for       $699.99 (JDR MicroDevices current price)
                 $745.95 (Products International)
 Your price used $425.00 obo
...I haven't gotten an offer at the asking price, so 'obo' applies...

I also have a 'broken' version of the scope which sold:
 JDR 2000 20MHz Dual-Channel Portable Analog Oscilliscope
   o 5mV/div
   o Component Tester (resistors/caps/diodes/coils)
   o TV video sync filter
   o z-axis input (intensity modulation)

'Broken' means: The CRT produces a nice, bright trace, but the trace does
not correspond to the input signal. My guess is it's repairable but more
than a simple calibration problem...but I honestly have not tried to
calibrate the scope or otherwise fix it. It's 'as-is'.
I paid $60 for it in its current state (I bought it thinking I'd repair it,
using the 'good' scope for side-by-side comparison...since I've sold the
'good' scope, the 'bad' one doesn't do me much good) and I'd like to recoup
that amount. As above, I'll accept offers and take the best one.

I'd prefer a local (Bay Area, California) buyer, so (a) I don't have to
ship it and (b) she or he can examine the scope prior to purchase.

rbn@apple.com

Newsgroup: sci.electronics
Document_id: 53670
From: nagle@netcom.com (John Nagle)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Wayne Alan Martin <wm1h+@andrew.cmu.edu> writes:
>Excerpts from netnews.sci.electronics: 16-Apr-93 Re: What do Nuclear
>Site's .. by R_Tim_Coslet@cup.portal. 
>> From: R_Tim_Coslet@cup.portal.com
>> Subject: Re: What do Nuclear Site's Cooling Towers do?
>> Date: Fri, 16 Apr 93 21:27:21 PDT
>>  
>> In article: <1qlg9o$d7q@sequoia.ccsd.uts.EDU.AU>
>>         swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) wrote:
>> >I really don't know where to post this question so I figured that
>> >this board would be most appropriate.
>> >I was wondering about those massive concrete cylinders that
>> >are ever present at nuclear poer sites. They look like cylinders
>> >that have been pinched in the middle. Does anybody know what the
>> >actual purpose of those things are?. I hear that they're called
>> >'Cooling Towers' but what the heck do they cool?
>Great Explaination, however you left off one detail, why do you always
>see them at nuclear plants, but not always at fossil fuel plants.  At
>nuclear plants it is prefered to run the water closed cycle, whereas
>fossil fuel plants can in some cases get away with dumping the hot
>water.  As I recall the water isn't as hot (thermodynamically) in many
>fossil fuel plants, and of course there is less danger of radioactive
>contamination.

       Actually, fossil fuel plants run hotter than the usual 
boiling-water reactor nuclear plants.  (There's a gripe in the industry
that nuclear power uses 1900 vintage steam technology).  So it's
more important in nuclear plants to get the cold end of the system
as cold as possible.  Hence big cooling towers.  

       Oil and gas fired steam plants also have condensers, but they
usually are sized to get the steam back into hot water, not most of the
way down to ambient.  Some plants do cool the condensers with water,
rather than air; as one Canadian official, asked about "thermal 
pollution" de-icing a river, said, "Up here, we view heat as a resource".  

       Everybody runs closed-cycle boilers.  The water used is 
purified of solids, which otherwise crud up the boiler plumbing when
the water boils.  Purifying water for boiler use is a bigger job than 
cooling it, so the boiler water is recycled.

					John Nagle

Newsgroup: sci.electronics
Document_id: 53671
From: sundar@fiber-one.ai.mit.edu (Sundar Narasimhan)
Subject: how much would a Tektronix 2465A oscilloscope fetch

Hi: I'd like to know how much the foll. equipment will fetch in the used
equipment market (without manuals or other accessories):
	1. Tektronix 2465 scope
	2. Tektronix 2465A scope
	3. Tektronix 1240 logic analyser

Thanks much for your help.

Newsgroup: sci.electronics
Document_id: 53672
From: rubin@cis.ohio-state.edu (Daniel J Rubin)
Subject: Re: what to do with old 256k SIMMs?

>>	I was wondering if people had any good uses for old
>>256k SIMMs.  I have a bunch of them for the Apple Mac
>>and I know lots of other people do to.  I have tried to
>>sell them but have gotten NO interest.

How hard would it be to somehow interface them to some of the popular 
Motorola microcontrollers.  I am a novice at microcontrollers, but I am
starting to get into them for some of my projects.  I have several 256k
SIMMs laying around from upgraded Macs and if I could use them as "free"
memory in one or two of my projects that would be great.  One project that
comes to mind is a Caller ID device that would require quite a bit of RAM
to store several hundered CID records etc...

                                                             - Dan
-- 
             Daniel Joseph Rubin     rubin@cis.ohio-state.edu 
     
                       GO BENGALS!      GO BUCKS!

Newsgroup: sci.electronics
Document_id: 53673
From: eabyrnes@vela.acs.oakland.edu (Ed Byrnes)
Subject: Getting rid of screen wiggles?

My monitor display has a bad case of the wigglies. I have a good ground. I
live in an old house and I have replaced much of the wiring. I have two
EMI filters on the computer, the monitor plugs into the computer. When
fluorescent lights are on upstairs, the display jiggles, when motors run
in the house, the display jiggles, when incandescent lights are on in the
kitchen the display jiggles.  I could bring a separate line from the
breaker box, and use it only for the computer, would this do it? EMI
doesn't only travel the 110 volt line though. Should I shield the back of
the monitor? Ground a grid or plate? 
Your expertise is appreciated. Thanks very much!  Ed Byrnes
-- 
*---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---*
|   Ed Byrnes   FAX:  313-651-7392           eabyrnes@vela.acs.oakland.edu  |
|   Kensington Academy & Oakland University    Rochester, MI North America  |
*---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---* 

Newsgroup: sci.electronics
Document_id: 53674
From: al@qiclab.scn.rain.com (Alan Peterman)
Subject: Fluke For Sale (was DMM Advice Needed)


I have a spare Fluke 8062A.  This is a true RMS digital meter with
4.5 digit display.  It's in "average" condition (been used) but 
works fine - which is what Fluke's are all about.   BTW - according
to the fellow who designed these meters, they can be converted to 8060A
function by clipping a jumper, and adding the 2 extra switches..
Like I said $115 seems fair - these sell for $300+ new.


-- 
Alan L. Peterman                                 (503)-684-1984 hm & work
                       al@qiclab.scn.rain.com
It's odd how as I get older, the days are longer, but the years are shorter!

Newsgroup: sci.electronics
Document_id: 53675
From: mcole@spock (COLE)
Subject: 8051 Microcontroller

I would like to experiment with the INTEL 8051 family.  Does anyone out  
there know of any good FTP sites that might have compiliers, assemblers,  
etc.?

Newsgroup: sci.electronics
Document_id: 53676
From: cjp1@aber.ac.uk (Christopher John Powell)
Subject: Fujitsu 8" HDD

I have a Fujitsu M2322K which has been removed (I believe) from a digital
X-Ray machine (takes X-Ray pictures without film).  The Fujitsu part number
is B03B-4745-B002A.

I have obtained some data on the device, it is 8-inch winchester-type
of 168 megabyte capacity (though I was told it was over 800 megabytes).
However, there is very little information on the interface standard used.
It appears to use two balanced-line connections, but what each connection
corresponds to I know not. One connection is a 30-way IDC, the other a
60-way IDC.

If anyone has any information on this device, I would be most grateful
if you could provide it.

Thanks.


Chris Powell.
-- 
+------------------------------------------------------------------------+
|  THE MAN FROM :  #####  #######  | JANET    : cjp1@uk.ac.aber          |
|                 #     #     _#   | Internet : cjp1@aber.ac.uk          |
|                 #     #  _#      | NYX      : cpowell@nyx.cs.du.edu    |

Newsgroup: sci.electronics
Document_id: 53677
From: billq@ms.uky.edu (Billy Quinn)
Subject: Re: Radio Shack Battery of the Month Club

donrm@sr.hp.com (Don Montgomery) writes:


>Radio Shack has canceled their "Battery of the Month" Club.  Does 
>anyone know why?  

>They say they'll honor existing cards in customer hands, but no new
>cards will be issued.

I was told that this is an environmental based move.  I was also told that
there will be 'somthing' else to replace the battery club.  Like maybe
the 360K floppy club ;-).

We'll see ....
-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*

Newsgroup: sci.electronics
Document_id: 53678
From: iisakkil@gamma.hut.fi (Mika Iisakkila)
Subject: Re: what to do with old 256k SIMMs?

rubin@cis.ohio-state.edu (Daniel J Rubin) writes:
>How hard would it be to somehow interface them to some of the popular 
>Motorola microcontrollers.

Not hard, you can do the refreshing and access cycles by software, but
this hogs most of the available CPU cycles on a low-end controller.
I've seen some application note from Philips that used one of their
8051 derivatives as a printer buffer, with up to 1MB of dynamic ram
that was accessed and refreshed with software bit-banging.

Another alternative would be to use one of those nice DRAM controller
chips that "create static RAM appearance" and all that, but they may
be too expensive to make it worthwhile.
--
Segmented Memory Helps Structure Software

Newsgroup: sci.electronics
Document_id: 53679
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Public-domain circuits in commercial applications

In article <1993Apr13.164924.2606@wuecl.wustl.edu> dp@cec1.wustl.edu (David Prutchi) writes:
>Can circuits found in electronics magazines (with no patent disclaimer)
>be used legally as subcircuits of a commercial unit ?

There are two issues here:  copyright and patent.

The magazine article's contents are copyrighted, and may not be reproduced,
translated, etc., without the copyright holder's permission.  However, this
does not cover the *ideas* expressed, only the form of expression.  Copying
their circuit diagram or PC-board pattern is copyright infringement.  But
it's unlikely that they could stretch copyright far enough to claim that
the circuit design itself is copyrighted.  So long as you draw your own
diagrams and lay out your own boards, copyright shouldn't be an issue.

Patents are different.  The author does *not* have to give you any warning
that the design is covered by patent (although it would be sensible for
him to do so).  In fact, it's possible that *he* was infringing on someone
else's patent without realizing it.  Ignorance of the patented status is
not a defence against infringement, although it might reduce the damages
a court would award.

However... unless there was something seriously novel about the circuit,
almost certainly it is "obvious to one skilled in the art" and therefore
unpatentable.  Routine engineering is not patentable; patents (in theory)
cover only inventions, ideas that are genuinely new.

Caution:  I am not a lawyer.  Consulting a professional would be wise if
significant amounts of money are at stake.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53680
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Public-domain circuits in commercial applications

In article <C5GE03.LIF@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>... Patent law says you can build anything
>you want to, for your own personal noncommercial use...

I'm not up on the details of US patent law, but I think this is incorrect.
There is a "reasonable use" exemption for *copyright*.  There is none for
*patents*.  The exemptions from patent licensing are quite narrow; R&D work
is exempt but personal use is not.  That is, it's okay to experiment with
a patented idea, but not to put it to practical use (e.g. to improve your
stereo), even if it's only your own private practical use.

Of course, it is unlikely that discreet personal use will ever be detected
or that you will ever be sued over it.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53681
From: fculpepp@norfolk.vak12ed.edu (Fred W. Culpepper)
Subject: CAD Program for Electronics?

I am making a search for a CAD program that does a decent job
of making schematic drawings.  The program needs to be in
MS-DOS, Windows if possible.

What I want the CAD program to do is to draw diagrams by
dragging elements onto the screen, and in this the elements
needed are as diverse as vacuum tubes to ICs (case with pins).
It also needs to have provision for adding legends to the
components as well as their values.  In other words I want to
produce quality drawings.  Printout would be to either 24 pin
dot-matrix and/or Laser Printer.

If you know of such a CAD program that is of reasonable cost,
please respond.

Fred W. Culpepper
OLD DOMINION UNIVERSITY (Retired)
fculpepp@norfolk.vak12ed.edu
---

Newsgroup: sci.electronics
Document_id: 53682
From: suwanto@iastate.edu (zapper)
Subject: Re: 2SC1096, 2SA634 specs?

>Could some kind soul post me the max power/voltage/current ratings of
>2SC1096 and 2SA634 transistors, their conductance types and pinouts.
>They are used in the sweep portion of a TV set.

2SC1096
  Maximum Ratings:
    VCBO = 40V
    VCEO = 30V
    IC   = 3A
    PC   = 10W (T=25C)

  ICBO max = 1uA
  VCB = 30V
  COB = 55pF

  at Q-point VCE=5, IC=1A --> hfe = 100

2SA634
  Maximum Ratings:
    VCBO = -40V
    VCEO = -30V
    IC   = -3A
    PC   = 10W (T=25C)

  ICBO max = -1uA
  VCB = -30V
  COB = 75pF

  at Q-point VCE = -5V, IC = -1A --> hfe = 100

That's all i can get from my data book, hope that helps.

suwanto@iastate.edu

    

Newsgroup: sci.electronics
Document_id: 53683
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: what to do with old 256k SIMMs?

rubin@cis.ohio-state.edu (Daniel J Rubin) writes:

>How hard would it be to somehow interface them to some of the popular 
>Motorola microcontrollers.  I am a novice at microcontrollers, but I am
>starting to get into them for some of my projects.  I have several 256k
>SIMMs laying around from upgraded Macs and if I could use them as "free"
>memory in one or two of my projects that would be great.  One project that
>comes to mind is a Caller ID device that would require quite a bit of RAM
>to store several hundered CID records etc...

Assuming 68HC11...
In expanded muxed mode, you *could* do it. Much easier if you get a DRAM
controller IC. The MMI 673102 could be used to implement this, or you
could use a counter and a huge multiplexer to provide row/column/refresh
address multiplexing. The thing with DRAMs is that they require wierd
timing, address multiplexing, and refresh.

Actually, if you wanted to use a 68008 IC, you could look at AN897, which
has a neat controller built in. There is also the 683xx, I think one
of those has the DRAM controller built in. This one is for the 6664
DRAM, however, the 41256 has only one more address line, adding only
another component or so. The 256k SIMMs are basically 8 or 9 41256
DRAM chips (or their equivalent in fewer packages).

It *can* be done, just takes a bit of logic design. I'm actually
about to do it using a 65C02P3 chip... I've got 8 256k simms... that's
2 megabytes on my Apple //e... (used to be in my '386).


Newsgroup: sci.electronics
Document_id: 53684
From: dannyb@panix.com (Daniel Burstein)
Subject: Re: What do Nuclear Site's Cooling Towers do?

<lots of pretty good stuff about how the huge towers near most nuclear
power plants are there to cool the used steam back into near ambient
temperature water deleted>

>>water.  As I recall the water isn't as hot (thermodynamically) in many
>>fossil fuel plants, and of course there is less danger of radioactive
>>contamination.

>       Actually, fossil fuel plants run hotter than the usual 
>boiling-water reactor nuclear plants.  (There's a gripe in the industry
>that nuclear power uses 1900 vintage steam technology).  So it's
>more important in nuclear plants to get the cold end of the system
>as cold as possible.  Hence big cooling towers.  

    as a point of info, some of the early nuclear power plants in this
country used the fission pile as a first stage to get the water hot, and
then had a second stage -fossil fuel- step to get the water (actually
steam) VERY HOT.

   I remember seeing this at Con Edison's Indian Point #1 power plant,
which is about 30 miles north of NYC, and built more or less 1958.


dannyb@panix.com

(all the usual disclaimers apply, whatever they may be)


Newsgroup: sci.electronics
Document_id: 53685
From: mustafa@seas.smu.edu (Mustafa Kocaturk)
Subject: How starters work really

In article <734953838.AA00509@insane.apana.org.au> peter.m@insane.apana.org.au (Peter Tryndoch) writes:
>
>So when you turn on the power, this causes the bulb to work like a neon, 
>heating up and shorting out, thus providing a loop to power the heaters in 
>the main tube. When the tube fires, insufficient current runs through the 
>starter to keep the heat up and the bi-metalic strip straightens out 
>(O/C).

Imprecise. This description

 1. ignores the role of the ballast,
 2. misrepresents the heating effects in the starter.

The bimetalic strip cools down immediately after the contacts
short circuit, because the neon discharge stops, and much less
heat is generated from the I^2R loss in the metal as compared to
the neon discharge.

The starter contacts open before the tube fires.  Actually,
the tube fires as a result of the back-emf generated in the ballast
because of this immediate opening of the starter's contacts.

A capacitor is connected in parallel with the contacts to prevent
excessive arcing during the firing.  The neon reionizes but does not draw
sufficient current to prevent firing of the tube itself.
-- 
Mustafa Kocaturk   mustafa@seas.smu.edu  EE Dept., Room 305A, Caruth Bldg.
Home: 214-706-5954  Office: 214-768-1475  SMU Box 753190, Dallas, TX 75275

Newsgroup: sci.electronics
Document_id: 53686
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: 74ACT???

In article <1qhrq9INNlri@crcnis1.unl.edu> mpaul@unl.edu (marxhausen paul) writes:
>OK, what's a quick rundown on all the 7400 series variations?  We're
>repairing something with a 74ACT00 on it and the question arises, "well,
>do  i really need the ACT part?"  Flipping through Digi-Key I see 
>ALS, AS, C, HC, AC, ACQ, ACT, HCT, ACHT, HCTLS...

Here's something I posted about this a few years ago.  It's not fully
up to date with all the new variations (some of which are just different
manufacturer's synonyms):

------
In practical terms, ignoring the technological details, this is my view
of the families (NB I am not a giant corporation, which influences my
views on things like availability and backward compatibility):

74	The original.  Speed good, power consumption fair.  Effectively
	obsolete now; use 74LS or later, except for a *very* few oddball
	functions like 7407 which are hard to find in newer families.

74H	Modification of 74 for higher speed, at the cost of higher
	power consumption.  Very obsolete; use 74F.

74L	Modification of 74 for lower power, at the cost of lower speed.
	Very obsolete; use CMOS.

74S	Later modification of 74 for even higher speed, at some cost in
	power consumption.  Effectively obsolete; use 74F.

74LS	Combination of 74L and 74S, for speed comparable to 74 with lower
	power consumption.  Best all-round TTL now, widest variety of
	devices.

74F	Fast as blazes, power not too bad.  The clear choice for high
	speed in TTL.  Availability and prices generally good.

74AS	Failed competitor to 74F, although a few 74AS parts do things
	that are hard to find in 74F and thus are still useful.

74ALS	Possible replacement for 74LS.  Generally souped up.  Still fairly
	new, availability and prices possibly a problem.

74C	Fairly old family, CMOS devices with TTL pinouts.  Competed with
	4000 series, not too successfully.  Obsolete; use 4000 or newer
	CMOS 74 families.

4000	(Thrown in as the major non-74 non-ECL logic family.)  The old CMOS
	family, still viable because of *very* wide range of devices, low
	power consumption, and wide range of supply voltages.  Not fast.
	Very forgiving and easy to work with (beware static electricity,
	but that comment applies to many other modern logic families too).
	There are neat devices in this family that exist in no other.  The
	clear choice when speed is not important.

74HC	A new attempt at 74-pinout CMOS.  Fast compared to old CMOS, power
	consumption often lower than TTL.  Possibly a good choice for
	general-purpose logic, assuming availability and affordability.
	CMOS logic levels, *not* TTL ones.  Beware very limited range of
	supply voltages compared to older CMOS, also major rise of power
	consumption at faster speeds.

74HCT	74HC with TTL logic levels.  Much the same comments as 74HC.  Read
	the fine print on things like power consumption -- TTL compatibility
	in CMOS involves some compromises.

10K	(Thrown in for speed freaks.)  The low end of ECL.  Various sources
	claim that it is *easier* to work with than super-fast TTL for
	serious high-speed work.  Less forgiving, though:  read and follow
	the rules or it won't work.  Availability to hobbyists limited,
	can be expensive.

100K	(For real speed freaks.)  Hot ECL.  Harder to handle than 10K, and
	inconvenient packages.  Much more useful datasheets, however.

As for compatibility between families:  the 74 families (except 74C and
74HC) are all more or less logic-level compatible, but how many 74X devices
you can drive from one 74Y output varies enormously with X and Y.  You just
have to read the specs and do the arithmetic.  74C and 74HC are compatible
with the others with a bit of hassle.  4000 compatibility can be a bit of
hassle or a lot of hassle depending on what supply voltage 4000 is using.
10K or 100K to anything else is considerable hassle.

Me?  I use 4000 and 74LS with a sprinkling of 74F.  74HC[T] and 10K are
interesting but I haven't used either significantly yet.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53687
From: jgd@dixie.com (John De Armond)
Subject: Re: What do Nuclear Site's Cooling Towers do?

swalker@uts.EDU.AU (-s87271077-s.walker-man-50-) writes:

>I was wondering about those massive concrete cylinders that
>are ever present at nuclear poer sites. They look like cylinders
>that have been pinched in the middle. Does anybody know what the
>actual purpose of those things are?. I hear that they're called
>'Cooling Towers' but what the heck do they cool?
>I hope someone can help 


The actual hourglass is hollow and is designed to generate a draft,
exploiting the venturi effect.  Around the base of the hourglass is a
ring of water towers.  Warm river water, coming from the steam condenser
in the plant, is sprayed over louvres.  The draft being pulled through
the tower cools the water by both evaporation and convection.  The
sensible heat extracted from the cooling water is the driving force for
draft generation.

It should be noted that the hourglass-shaped cooling towers are used on
both fossile and nuclear plants.  It should also be noted that at 
locations where water is plentiful, the cooling towers are only used part
time, when the discharge temperature would exceed some release limit.
It was once thought that the warm discharge water was damaging to fish.
Fishermen know that is thoroughly incorrect.  Nontheless, stringent,
usually state, regulations remain in some instances.  Since it typically
takes 60,000 hp worth of pumping to move the volume of water needed 
to cool a 1000 MWe plant, the cost of using the towers is not insignificant.
-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine(TM) | Interested in high tech and computers? 
Marietta, Ga                         | Send ur snail-mail address to 
jgd@dixie.com                        | perform@dixie.com for a free sample mag
Lee Harvey Oswald: Where are ya when we need ya?

Newsgroup: sci.electronics
Document_id: 53688
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: making copy of a Video tape

hooperw@spot.Colorado.EDU (Wayne Hooper) writes:

> victor@inqmind.bison.mb.ca (Victor Laking) writes:
> 
> >You are experiencing what is called Macrovision.  It is the protection 
> >that they use on the video tapes.  There are two ways around this that I 
> >know of.  First of all, you can try using a different VCR to copy onto.
> >It is the input of the VCR that reacts to the protection so sometimes 
> >just switching the two VCRs around will take care of it.  Some models 
> >just don't react to it.
> 
> Does this also affect the viewing of tapes ? I have had problems with
> a couple of rented tapes; they were virtually unviewable. I fiddled 
> with the tuning, tracking and vertical hold but it was no good.
> 


It sounds like your TV is one of the ones that also reacts to the video 
protection.  (Poor you!)

The Macroscrubber from Radio Electronics removes the protection so you 
souldn't have any more problems.  However, if you use the method of 
copying it from one VCR to another where the second VCR doesn't react to 
the protection, you will end up with a duplicate tape, including the 
protection.

One thought comes to mind about your problem...  When playing the tape 
for viewing, are you feeding the signal from the source VCR through an 
extra device before going to the TV?  If you feed it through a second VCR 
first, that is your problem.  As to other devices such as converters, I 
don't know if they would react or not.  Just to be safe, you might want 
to make sure that you have NOTHING between the VCR and TV.

victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 53689
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: CRT driver transistors

Device........ LT1839   @ IC (mA)..... 50
V(BR)CEO (V).. 70       CCB (pF)...... 2.5
V(BR)CBO (V).. 120      VCE (V)....... 15
IC (mA) max... 300      Polarity...... NPN
hFE min....... 20       Package....... 79-04
hFE max....... 60       Material...... Metal
fT (GHz)...... 1        Price (100+)..

Device........ LT5839   @ IC (mA)..... 60
V(BR)CEO (V).. 65       CCB (pF)...... 1.5
V(BR)CBO (V).. 80       VCE (V)....... 10
IC (mA) max... 300      Polarity...... PNP
hFE min....... 15       Package....... 79-04
hFE max....... 60       Material...... Metal
fT (GHz)...... 1.5      Price (100+)..
@ VCE (V)..... 10

Anyone know of a source for these parts (other than straight from
Motorolla)?  I need 4 Lt1839's and 2 Lt5839 I've tried standard
and they said "We are out!"

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 13:50:28

... If there's one thing I can't stand, it's intolerance.
---
 * Blue Wave/QWK v2.12 *
                                                       

Newsgroup: sci.electronics
Document_id: 53690
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: Analog switches/Balan

{Michael Fulbright} said
   "Analog switches/Balanced"
      to <All> on 04-15-93  01:08
 MF> I am trying to build a synchronous demodulator and I've hit a snag.
 MF> In my application I want to be able to change the gain of an
 MF> op amp amplifier from 1 to -1, controlable via a digital input.
 MF> The most obvious way I've come up with is to use analog switches
 MF> to adjust the gain of the op amp. The only analog switch I have
 MF> experience with it the 4066. Unfortunately I want to switch an
 MF> AC signal which goes from about -5V to 5V, and the 4066 is only
 MF> for positive signals.

    How about using a 4053 it has a seperate ground for the
    analog outputs.  It would get you 3 bits.

 MF> Another part which caught my eye was the Analog Devices AD630. This
 MF> is a balanced demodulator which appears to fill exactly the need I
 MF> have. The data sheet was somewhat skimpy on application notes. Could
 MF> someone comment on using this chip for the following application?

    Or how about a multiplying D/A convertor?  This is
    essentiallty what you are makeing.


                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 13:36:11

... Catch the Blue Wave!
---
 * Blue Wave/QWK v2.12 *
                          

Newsgroup: sci.electronics
Document_id: 53691
From: v064mb9k@ubvmsd.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Need diode model for PSpice


	Im designing a circuit with just a silicon diode. I dont need
to modify any of the parameters. But the problem will not accept the following
statement
		
		.model diode D

        The pspice book I have is terrible. I would appreciate any help.


                                  Neil Gandler
 _____________________________________________________________________________
       Gandler Electronics
                            Home Automation & electronic design technology
 _____________________________________________________________________________

Newsgroup: sci.electronics
Document_id: 53692
From: mlee@eng.sdsu.edu (Mike Lee)
Subject: Wire-Amperage table needed


Does anyone has a table about the size of the wire to the amount of current it can carry.  Probably in the 1-15amp range.  My friend is interested in converting a Mazda into an electric car.  Needed information for estimation.  Thanks in advance.  

p.s. any info on electric will be greatly appreaciated.  


Newsgroup: sci.electronics
Document_id: 53693
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: making copy of a Video tape

In article <136390006@hpcuhe.cup.hp.com>, pi@hpcuhe.cup.hp.com (Paul Ilgenfritz) writes:
> 
> I think the Go Video dual cassette machines do a direct tape to tape copy
> which transfers Macrovision to the copy.  I you can find one of these, it
> would be worth a try.

Go-Video machines used in HQ2 mode will copy even the MacroVision.
Go-Video phone number (602)998-3400. 

Ask for sales department. Since the state of Arizona does not go on 
Daylight Savings time, we effectively are in Pacific time zone.

Allen Sullivan
Designing various stuff for GO-Video

Newsgroup: sci.electronics
Document_id: 53694
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: What do Nuclear Site's Cooling Towers do?

Others said:
# >       Actually, fossil fuel plants run hotter than the usual 
# >boiling-water reactor nuclear plants.  (There's a gripe in the industry
# >that nuclear power uses 1900 vintage steam technology).  So it's
# >more important in nuclear plants to get the cold end of the system
# >as cold as possible.  Hence big cooling towers.  

When the utility gave up on that Cinnci, OH plant (Zimmer?) and
announced they were going to convert it to a coal-fired scheme, the
turbines were already in place, and they were the low-temp type. So the
plan was: Install a SECOND set of high temp turbines, and feed the
low-temp ones with the output of the new ones.

Never saw anything more on this. Did they ever really build it?
--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
Document_id: 53695
From: wb8foz@skybridge.SCL.CWRU.Edu (David Lesher)
Subject: Re: 74ACT???

Others said:
# 74S	Later modification of 74 for even higher speed, at some cost in
# 	power consumption.  Effectively obsolete; use 74F.
# 
# 74LS	Combination of 74L and 74S, for speed comparable to 74 with lower
# 	power consumption.  Best all-round TTL now, widest variety of
# 	devices.
# 
# 74F	Fast as blazes, power not too bad.  The clear choice for high
# 	speed in TTL.  Availability and prices generally good.

I hate to disagree w/ a fellow as smart as Henry, but...

A few years back, I worked on a project using lots of high-speed
stuff.  (My part was slow & parallel, whew.) The mild-mannered designer
working on the fast (serial) stuff cussed & swore at 74F all the time.
It was the Harry Reams of TTL. One ultra-tiny power line glitch, one
hickup, one eyeblink across the board, and bang - the F had
toggled/counted/whatevered.  At times he swore it would count even
without any 5 volt supply ;-} You can guess what the "F" stood for....

They would do anything to push S or work around it to avoid using F. I
don't think I'd consider using F to replace S unless the consequences
were *fully* understood.......
--
A host is a host from coast to coast..wb8foz@skybridge.scl.cwru.edu
& no one will talk to a host that's close............(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newsgroup: sci.electronics
Document_id: 53696
From: ah499@cleveland.Freenet.Edu (John Daniels)
Subject: HELP!: Apple II Expansion Chassis by Mountain Computer


I recently bought an apparantly complete Expansion Chassis by Mountain
Computer Inc.  It consists of a box with 8 Apple ][+ compatible slots,
powersupply brick, interface card and ribbon cable to attach it to the computer
to be expanded.  There was also included a small card with empty sockets on top
and pins on the bottom that looks like it would plug into the ][+ motherboard
somewhere after pulling a chip.  There's an empty socket also on the interface
card and a short 16-pin DIP jumper like the ones used with ][+ language cards.
 
This technological marvel came with no docs and I haven't a clue as how to hook
this thing up.  If anyone has docs and/or users disk of any sort for this I
could really use copies of them or at least some help.
 
I need to know:
 
o How to orient the ribbon cable between the card and the chassis.
o How to attach the short cable from the motherboard to the card
  and if the small card is used.
o The purposes of the various jumper-pins on the card (it has more
  of those than my CMS SCSI card!)
 
 
thanks                                          John Daniels
                                                ah499@cleveland.freenet.edu
 

Newsgroup: sci.electronics
Document_id: 53697
From: surfer@world.std.com (Internet Surfer)
Subject: 6551A and 6551 compatibility

Does any one know if the 6551 is timing/pin compatible with the 6551.. 
It seems the 6551 has in iheirent bug with cts/rts handshaking and i need
a suitable pin replacement to put in my serial card... possibly a buffered
version perhaps?


-- 
jolt@gnu.ai.mit.edu	      |    Its not impossible, just improbable
johnp@pro.angmar.uucp         |            (Zaphod Beeblbrox)
bl298@cleveland.freenet.edu   |   N1NIG@amsat.org (Being a Ham is so grand)

Newsgroup: sci.electronics
Document_id: 53698
From: griffin@camelot.bradley.edu (Mark Valentine)
Subject: HELP: 20ma current loop to RS232 converter needed.


	Where can I buy or build a device that will convert 20 ma
current loop signals to RS232 voltages?  I know some old terminals
came with that option, but none of the ones I own have that.  Anyway,
I want to connect a computer to this old industrial computer to use
the computer with communications software as a console instead of
an old DecWriter.  Please e-mail me if you have any info that would
point me in the right direction.  



Newsgroup: sci.electronics
Document_id: 53699
From: chris@alien.saar.de (Christian Reisel)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In <C5L5x0.KJ7@vcd.hp.com>, John Eaton writes:

   [...]
>During the nuclear fission reaction the uranium fuel can get hot enough
>to melt. When this happens the liquid uranium is pumped to the cooling
>tower where it is sprayed into the air. Contact with the cool outside air
>will condense the mist and it will fall back to the cooling tower floor.
>There it is collected by a cleaning crew using shop vacs and is then
>reformed into pellets for reactor use the next day.
>
>Cooling towers are a lot taller than they really need to be. Power companies
>are forced to make them that tall by some enviromental law that requires the
>raw uranium emisions to be held to under 1%. This law is now under attack
>by lawyers arguing that the 1% should be measured at the edge of the property
>rather than the edge of the cooling tower. Eliminating this law will save
>power companies thousands of dollars in concrete costs for new nukes.
>
>John Eaton
>!hp-vcd!johne
>

I think you posted your article 15 days too late :-)) April 1st is over.
I don't like nuclear powerplants but i think it's not fair to tell such
"storys" about them. OK ?
Let me try to explain what that tower is used to:
   -1st. Even the modernst nuclear powerplant is only a simple steam-engine.
         It has an hightech "boiler" but the rest is still verry verry 
         conventional. And if you've already visited any condensation-
         powerstation you'l have seen the cooling towers too.
         If you look at any good book about thermophysics you'll find
         a chapter about the "CARNOT-process" which describes how to
         get energy from a temperature difference ! And that is the reason
         for cooling towers too !!! You only can get energy if you've an
         temperature gradient. That means that you have steam on the one 
         side and need to cool down the steam 'till you get water
         again on the other side if you want to get aprox. 30% of the 
         energy you (or better the uranium) brought into the water to
         let it boil. If you only have hot steam on the one and "cold"
         steam on the other side you'll loose much more of the energy.
         And so they cool down the steam to get at least the 30% of
         energy that carnot will give them.
         The cooling towers are for cooling the steam !
         The vapor you'll see is NOT the steam of the main core circulation,
         because that steam is radioactive ! The circulation is divided in
         AT LEAST 2 circuits connected about heat exchangers to prevent
         radioactive pollution of the environment !
         
   -2nd. OK, the main core IS hot, but even in the modernst HighTemperature-
         Reactors (HTR) they only run at ~800 deg celsius. This is still
         verry far away from uraniums melting point which is somewhere
         around 2000 deg. celsius ! But you'll have lot's of problems with
         the boiler's steel. That's because at this temperature the
         metal is attacked by steam and will corrode verry fast.
         This is only for BWR's. The new He cooled reactors have temperatures
         up to 1200 deg. celsius. But this is only experimental. 

   -3rd. I personaly think that nuclear waste should be as low as ever
         possible because the dose you get will accumulate about the
         years. Today 1 mRem and next year 0.5 mRem won't be 0.75 mRem
         at all. It accumulates and even in 80 years you'll still have
         1.5 mRem. And i'm not interested in glowing in the night and
         getting children with 2 heads. This is my point of view.
         

Only my 0.02$ !

Christian Reisel 

student of electronic sciences

-- 
Christian Reisel, Goldammerweg 2, W-6601 Buebingen, Germany
Voice        +49 6805 22179 Fax & Email  +49 6805 22179

PGP PubKey:
--------------------------------------------------------------
begin 777 pcr.pub
MF5L`P`"S*Q%296ES96PL($-H<FES=&EA;OX!P7R5'F0QY1Q_.=+SY(;DZ0L:6
MMO(]]0`=K?/VH[U-"6MX]7G\-MF]/;&`H5KL/%,M\$:89^5FI6;W:$T$;9M!Q
$+04`$0`=@
``
end

Newsgroup: sci.electronics
Document_id: 53700
From: adykes@jpradley.jpr.com (Al Dykes)
Subject: help: How to reduce the RPMs of a Boxer fan ?


I need to reduce the speed of a Boxer fan by about 30-50%. I recall
reading somewhere that the right capacitor in series will do it.

If this isn't a case of brain fade, can someone suggest the cap value ?

The specifics; It's a real Boxer Fan (tm). The label says 115 V, .2 amps.

Al Dykes
--------
adykes@jpr.com






Newsgroup: sci.electronics
Document_id: 53701
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: **] A/D board quiry:

 
        On an A/D board I've got, I'm using the A/D lines.  It measures 
the voltages properly, ie: with a 7v power supply it reg's 7v and with 
5v, it reg's 5v.  Problem is when I've got the input voltage, and I wish 
to lower it via a resistor.  The sensitivity of the board is so great 
that I can triger it with holding the 5/7v wire in one hand, and touch 
the probe and it will register the full input voltage.  A 1m resistor 
only lowers voltage by .1v so this is not too feesable. 
 
                What could the problems be and what else could I use
to lower the input voltage?  (btw I've got it grounded correctly)
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
Document_id: 53702
From: alee@ecs.umass.edu
Subject: Need to find out number to a phone line


Greetings!
      
        Situation:  I have a phone jack mounted on a wall.  I don't
                    know the number of the line.  And I don't want
                    to call up the operator to place a trace on it.

        Question:   Is there a certain device out there that I can
                    use to find out the number to the line?
        Thanks for any response.
                                                    Al

  

Newsgroup: sci.electronics
Document_id: 53703
From: frankh@scraps.uucp (Frank Holden KA3UWW)
Subject: Re: What's a good IC for RS232 -> TTL signals??

In <C57zsC.9FL@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:



>I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
>levels.  Something relatively inexpensive would be nice, too.  Anyone have
>a suggestion??  Thanks.


Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
you want.  They are selling it for about $3.50...

Hope this helps...
Frank

-- 

**************************************************************************
* Customer asked "What's that thing?".                                   *
* I answered chuckling "Well, it's a highly technical, sensitive         *
* instrument I use in computer repair! Being a layman, you probably      *
* cann't grasp exactly what it does. I call it a B.F.H.....              *
* Frank W. Holden - KA3UWW - "The Radio Doctor"                          *
* - - - - - - - - - - - - - - - - - | - - - - - - - - - - - - - - - - -  *
* SnailMail:                        | Inter-Net:                         *
* 685 Addison St.                   | frankh@scraps.pittsburgh.sgi.com   *
* Washington, Pa. 15301-5601        | Packet:ka3uww@n3idi.#wpa.pa.usa.na *
**************************************************************************
DISCLAIMER:<disclaimer.h> - I confess, you did it!!!
-- 

**************************************************************************
* Customer asked "What's that thing?".                                   *
* I answered chuckling "Well, it's a highly technical, sensitive         *

Newsgroup: sci.electronics
Document_id: 53704
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: Need to find out number to a phone line

alee@ecs.umass.edu writes:


>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.

>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al

There usually is a way, however, often, telephone companies like to
keep all of their internal numbers private. Depends on your exchange.
Any modern electronic switching equipment usually have voice synth
lines that echo the number you called from. The line service guys use this
to make sure they connect up the right pairs of lines.



Newsgroup: sci.electronics
Document_id: 53705
From: bryan@philips.oz.au (Bryan Ryan)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)

spp@zabriskie.berkeley.edu (Steve Pope) writes:

>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>	Hello again,
>> I asked this a year ago, but i am still looking.
>> I am getting sick of having to use a HC373 

>Jeff, just use the damned 373.   Sure, there are oddball
>latched memory chips, but do you really want to use them?

>Sorry if I'm pedantic but: design your circuit using
>reasonably available parts, and move on to more important
>problems.

We're looking at a series of chips by WSI, the PSD3xx series. They have
_mega_ address decoding logic on them, various ROM sizes (upto 1Mbit),
various RAM sizes (upto 16 K), and 19 I/O ports which can be chip select
lines, I/O or the buffered address lines.

Cute chip, 44 pin PLCC package.

Second sourcing may be a problem though :-(


Bryan Ryan, VK3TKX
Melbourne, Australia
bryan@philips.oz.au


Newsgroup: sci.electronics
Document_id: 53706
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: what to do with old 2

{Jason Haines} said
   "what to do with old 256k"
      to <All> on 04-15-93  04:38

 JH> I was wondering if people had any good uses for old
 JH> 256k SIMMs.  I have a bunch of them for the Apple Mac
 JH> and I know lots of other people do to.  I have tried to
 JH> sell them but have gotten NO interest.

    How about collecting them all together (IE everyones) and
    selling them as a lot?  The other thing is to give to a
    recycler.

 JH> So, if you have an inovative use (or want to buy
 JH> some SIMMs  8-) ), I would be very interested in hearing
 JH> about it.

    If they are free and you can send them real cheap!  I would
    be intrested in them.  hehehe  Are these 2 chip or 8 chip
    devices what speed?

 JH> I have seen RAM disc storage devices but they have been
 JH> very pricey (plus I am still a little worried about having data
 JH> stored on RAM).

    Why?  Do you use a RAM disk? :)

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Fri  04-16-1993  at 19:58:29

... Badgers... we don't need no steenking Badgers!
___ Blue Wave/QWK v2.12
                                                        

Newsgroup: sci.electronics
Document_id: 53707
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: what to do with old 2

{Kris Gleason} said
   "Re: what to do with old 2"
      to <All> on 04-15-93  11:02
 KG> Yeah... keychains.  I have seen 64K simms with a silver 
 KG> keyring attached, big seller at the computer store.  I'm
 KG> sure you could find a bunch of geeks^H^H^H^H^H^H computer
 KG> science majors around that would buy them for $10.  Maybe
 KG> $15, if you're lucky.

    Untrue they would check JDR first and say 5.  That's how much
    they are worth AT MOST.  My guess is they are worth 1 buck
    a peice.

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Sat  04-17-1993  at 20:26:37

... This tagline is a duplicate.   This tagline is a duplicate.
___ Blue Wave/QWK v2.12
                                                                     

Newsgroup: sci.electronics
Document_id: 53708
From: thompson@cactus.org (Charles Thompson)
Subject: How does "Differential Mode" GPS work???



I understand that the new GPS boxes now have an option
known as "differential ready".  Apparently land-based
beacons tranmit GPS correction information to your GPS 
receiver (with differential option installed).

How does this system work?  What frequency is used for
the land-based beacons?

Thanks in advance,

Charlie Thompson
.


Newsgroup: sci.electronics
Document_id: 53709
From: ski@wpi.WPI.EDU (Joseph Mich Krzeszewski)
Subject: Re: Need to find out number to a phone line

In Texas (Well, Corpus Christi anyway) if you pick up the phone and dial
890 the phone company will read back the number to you.
Try it. It might work.


Newsgroup: sci.electronics
Document_id: 53710
From: rcook@gfx.engga.uwo.ca (Richard Cook)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al
>
>  


How about calling someone with the Caller ID service and have them call you back
with the number?

-- 

Richard Cook    (519) 641-1985     E-mail:  rcook@gfx.engga.uwo.ca
Elect. Eng. FAX	(519) 661-3488

Newsgroup: sci.electronics
Document_id: 53711
From: markz@ssc.com (Mark Zenier)
Subject: Re: Can I use a CD4052 analog multiplexer for digital signals?

Tall Cool One (rky57514@uxa.cso.uiuc.edu) wrote:
: As the subject says - Can I use a 4052 for digital signals?  I don't see
: why it couldn't handle digital signals, but I could be wrong.  Anyone have
: any advice?  Thanks.

The switches have a non-negligable on resistance (up to 1k ohm when
powered by 5 volts) and a maximum current and a Maximum Static
Voltage Across Switch.  Not a good bet for TTL.  Should work for
CMOS, but slow things down a bit.  There are 74HC versions that
have better specs. but lower max voltage.

Mark Zenier  markz@ssc.wa.com  markz@ssc.com  


Newsgroup: sci.electronics
Document_id: 53712
From: markz@ssc.com (Mark Zenier)
Subject: Re: Illusion

Chris Best (cab@col.hp.com) wrote:
: > This is not a new idea.  At least 10 years ago I got this little gadget with
: > a keyboard on the back and 8 LED's in a vertical row on the front.  It has a
: > long handle and when you wave it in the air it "writes" the message you typed
: > on the keyboard in the air. 
: 
: This is not news.  In fact it's where I got the idea from, since it was
: such a neat item.  Mattell made it, I believe, modeled after a "space 
: saber" or "light sword" or something likewise theme-y.  My addition was 
: using a motor for continuous display, and polar effects in addition to 
: character graphics.  I should have protected it when I had the chance.  
: No one to kick but myself...
: 
: Ten years ago is about right, since I built mine in '84 or '85.

It's even older than that.  I remember seeing a description of
a garage operation selling them at some of the early Computer Faires 
in San Francisco about 5 years before that.


Mark Zenier  markz@ssc.wa.com  markz@ssc.com  


Newsgroup: sci.electronics
Document_id: 53713
From: dnewman@lynx.dac.northeastern.edu (David F. Newman)
Subject: voltage regulator spec needed !!!!!

Hi there,
I have a mac 512 with a burned out part which looks like a voltage
regulator.  The part number is BU 406 and I believe the vender is
SGS thomas judging by teh SGS logo printed on the package.  If anyone
has teh spec for this part I would greatly appreciate an email with
the import info so I can find a replacement.  Thanx in advance.

-Dave
dnewman@lynx.northeastern.edu

BTW I don't need people telling me to throw the computer away.  If
  I had the money the thing would be in the trash in a second, but
  it does make a good terminal if nothing else.

Newsgroup: sci.electronics
Document_id: 53714
From: berryh@huey.udel.edu (John Berryhill, Ph.D.)
Subject: Re: What do Nuclear Site's Cooling Towers do?

The object of a cooling tower is to distribute dissolved salts in 
cooling water over large areas of farmland and to therefore decrease
farm subsidies for non-producers by rendering their land infertile.

A side effect of this deficit-reduction program is that they provide
a low-T reservoir for a variety of industrial processes.

Now you know. 

-- 

                                              John Berryhill


Newsgroup: sci.electronics
Document_id: 53715
From: xandor@unixg.ubc.ca (John Gilbert )
Subject: Re: Exploding TV!

 Just as a not of possible interest on this subject ..
It is my understanding that exploding televisions were a major cause of
domestic accidents in the Soviet Union in past years!
  

Newsgroup: sci.electronics
Document_id: 53716
From: jeh@cmkrnl.com
Subject: Re: A question about 120VAC outlet wiring.

In article <1qmisf$odp@sdl.Warren.MENTORG.COM>, garyg@warren.mentorg.com (Gary Gendel) writes:
> In article 1834@cmkrnl.com, jeh@cmkrnl.com writes:
>>What you CAN do if you want three-prong outlets without additional wiring is 
>>to use a GFCI outlet (or breaker, but the outlet will be cheaper).  In fact,
>>depending on where you are putting your new outlet(s), a GFCI may be *required*.
> 
> You still need to supply a proper ground for a Ground Fault Circuit Interrupter!

Not according to the NEC nor the CEC, as explained in the electrical wiring 
FAQ, which I posted here separately.  Note the material under the headings

> Subject: How do I convert two prong receptacles to three prong?

and

> Subject: Are you sure about GFCIs and ungrounded outlets?
> 	Should the test button work?

Of course, as they said -- "Local codes may vary". 

> So rewiring is still a part of this job, however, the ground may be connected to
> a local earth ground, rather than back at the breaker box.

I'm not sure about this.  If the ground connections on the outlets are
connected to anything, they should be connected to a wire that runs back to the
main panel, where it is bonded to the neutral connector and to the house ground
rod.  A connection to a local earth ground would not necessarily meet one of
the goals of the ground wire, which is that if a short develops from hot
to the ground wire, enough current would flow to trip the breaker.  

Hmmm.  How are those orange "isolated ground" outlets (often used in
computer rooms) wired?  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
Document_id: 53717
From: sgberg@charon.bloomington.in.us (Stefan G. Berg)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu> st1my@rosie.uh.edu (Stich, Christian E.) writes:
> I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
> 68030 + 68882 with capability to clock the FPU separately).  Previously
> a MC68882RC25 was installed and everything was working perfectly.  Now the
> systems displays a yellow screen (indicating a exception) when it check for
> the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
> fine, but with the XC68882 even at 25 MHz it does not work.  The designer
> of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
> might help, but that didn't change anything.  Does anybody have some
> suggestions what I could do?  Does this look like a CPU-FPU communications
> problem or is the particular chip dead (it is a pull, not new)?
> Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
> that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
> Are there any MC68882RC33?

I, too, have a XC68882RC50 math coprocessor, which I installed
succesfully in my Mega Midget Racer (clocked at 33 MHz). I have tried
clocking my FPU at 28 to 50 MHz and it all worked just fine. I have a
MC68030-33 CPU. I don't know why my FPU has an XC (my original 33MHz FPU
was label MC68882-33), but it seems to work fine on my system. Maybe you
just have a bad chip.

Stefan

P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)

Newsgroup: sci.electronics
Document_id: 53720
From: mniederb@pws2.itr.ch (Niederberger Markus)
Subject: Characterization of opamps

Hi,

Right now I should do some characterization of opamps. Because I don't  
have
special equipment for this task, I have to do this job with relativly  
simple
equipments (Frequency sweeper, DSO, etc.). 
Does anyone know good test circuitry for characterization of opamps? 
Especially for measuring open-loop gain, phase margin, PSSR, CMMR and so  
on.
Are there any books or application notes on this subject available?

Please reply vi e-mail or nn.

Thanks
Mark

__________________________________________________________________________ 
_____
Mark Niederberger
E-mail: mniederb@itr.ch
__________________________________________________________________________ 
_____

Newsgroup: sci.electronics
Document_id: 53721
From: hjkim@hyowon.pusan.ac.kr (Hojoong Kim)
Subject: Looking for Electronics Dept Info in Austrailia

Hi Netters!

I am looking for the list of universities in Austrailia, which has electronics department. 
I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
But I don't have any information about Austrailian Universities.
Can anybody recommend a good university in communication area?
Any comments will be welcomed!

Bye.

Jaehyung Kim


Newsgroup: sci.electronics
Document_id: 53722
From: jgd@dixie.com (John De Armond)
Subject: Re: What do Nuclear Site's Cooling Towers do?

nagle@netcom.com (John Nagle) writes:

>>Great Explaination, however you left off one detail, why do you always
>>see them at nuclear plants, but not always at fossil fuel plants.  At
>>nuclear plants it is prefered to run the water closed cycle, whereas
>>fossil fuel plants can in some cases get away with dumping the hot
>>water.  As I recall the water isn't as hot (thermodynamically) in many
>>fossil fuel plants, and of course there is less danger of radioactive
>>contamination.

Actually the reasons you don't see so many cooling towers at fossil plants are
1) fossil units (multiple units per plant) are generally smaller than
nuclear plants.  300 MWe seemed to be a very popular size when many
fossil plants were built.  The average nuclear plant is 1000 MWe.  2) many
fossil plants were grandfathered when water discharge regulations were
adopted ("why those old dirt burners can't harm anything, let 'em go.").  
3) powered draft cooling towers, low enough to the ground to be generally
not visible from off-site, are quite popular with fossil plants.  4) fossil
plants used to get much less regulatory attention than nuclears.

>       Actually, fossil fuel plants run hotter than the usual 
>boiling-water reactor nuclear plants.  (There's a gripe in the industry
>that nuclear power uses 1900 vintage steam technology).  So it's
>more important in nuclear plants to get the cold end of the system
>as cold as possible.  Hence big cooling towers.  

>       Oil and gas fired steam plants also have condensers, but they
>usually are sized to get the steam back into hot water, not most of the
>way down to ambient.  Some plants do cool the condensers with water,
>rather than air; as one Canadian official, asked about "thermal 
>pollution" de-icing a river, said, "Up here, we view heat as a resource".  

Actually the condensing environment is essentially the same for plants
of similar size.  The issues are the same regardless of where the 
heat comes from.  Condensers are run at as high a vacuum as possible in
order to reduce aerodynamic drag on the turbine.  The condenser pressure is
normally water's vapor pressure at the condensing temperature.  It is
desirable that the steam exhaust be free of water droplets because 
moisture in the steam causes severe erosion damage to the turbine 
low pressure blades and because entrained water moving at high velocity
causes erosion of the condenser tubes.  The coldest and thus lowest
pressure condensing environment is always the best.  

A related issue is that of pumping the condensate from the hotwell (where
the water ends up after dripping off the condenser tubes.)  Since the
condenser is at a very low pressure, the only force driving the 
condensate into the hotwell pumps is gravity.  If the condensate is too 
hot or the gravity head is too low, the condensate will reflash into
steam bubbles and cause the condensate pumps to cavitate.  This is a
particularly destructive form of cavitation that is to be avoided at all
costs.  

The hotwell pumps are located in the lowest point in the plant
in order to provide a gravity head to the pumps.  How much lower 
they must be is a function of how hot the water is allowed to get in
the hotwell.  Typically hotwell temperatures run between 100 and 120 
degrees depending on the temperature of the river water (this term is
used to describe the river grade water even when the cooling tower
system is operating in closed loop mode and essentially no river water
is pumped.)  When the river water temperature is high in the summer,
operators will typically allow the hotwell level to rise in order 
to provide more gravity head.  There is a tradeoff involved since higher
hotwell levels will encroach onto the condensing tubes and reduce the
condenser area.

At least in the East and elsewhere where moisture actually exists in the
air :-), the river water will almost always be cooler than the discharge
water from the cooling towers.  The temperature of the discharge water
from the cooling towers is set by the ambient air temperature and
humidity.  It is very rare in the East to hear of actual river water
temperatures exceeding 70 degrees.  A vast difference from the typical
"95-95" days (95 degrees, 95% humidity) we see routinely in the East.
It is not unusual, particularly where the econazis have been successful
in clamping rigid discharge water temperature limits on a plant, for the
plant to have to reduce the firing rate when the air temperature gets
too high and the condenser cannot handle the heat load without excessive
pressure.

>       Everybody runs closed-cycle boilers.  The water used is 
>purified of solids, which otherwise crud up the boiler plumbing when
>the water boils.  Purifying water for boiler use is a bigger job than 
>cooling it, so the boiler water is recycled.

True.  Actually secondary plant (the part that makes electricity and
feeds feedwater to the boiler) water chemistry has been the bastard 
stepchild until recently and has not gotten the respect it deserves.
The plant chemists have just in the past decade or so fully understood
the costs of impure water.  By "impure", I mean water with a few
dozen extra micromho of conductivity and/or a few PPM of dissolved
oxygen.  Secondary water is now typically the most pure one will 
find outside the laboratory.

John
-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine(TM) | Interested in high tech and computers? 
Marietta, Ga                         | Send ur snail-mail address to 
jgd@dixie.com                        | perform@dixie.com for a free sample mag
Lee Harvey Oswald: Where are ya when we need ya?

Newsgroup: sci.electronics
Document_id: 53723
From: marrevola@rediris.es
Subject: Re: What is Zero dB????

In article <1993Apr6.132429.16154@bnr.ca>, moffatt@bnr.ca (John Thomson) writes:
> Joseph Chiu (josephc@cco.caltech.edu) wrote:
> 
> : And the measure of current, Amp, is actually named after both the AMP company
> : and the Amphenol company.  Both companies revolutionized electronics by
> : simulatenously realizing that the performance of connectors and sockets 
> : were affected by the amount of current running through the wires.
> 
> Sorry.  The unit for current is the AMPERE which is the name of a french-man
> named AMPERE who studied electrical current.  The term AMP is just an abbreviation
> of it.  The company AMP came after the AMPERE unit was already in use.
>   
> : The Ohmite company was the first to characterize resistances by numbers, thus
> : our use of the Ohms...
> 
> I don't know about this one, but it doesn't sound right.
Are you (two) joking?
Is the entire Internet flaming you (two)?
Ahh!, now I remember that Ohmite company was the first introducing "the pink
colored resistor", only for electronics working females ;-)
-- 
Manuel Arrevola Velasco   ||||| True e-mail: manolo@taf.fundesco.es |||||
DoD #1033


Newsgroup: sci.electronics
Document_id: 53725
From: webb@itu1 (90-29265  Webber  AH)
Subject: Re: Adcom cheap products?

Aaron Lung (alung@megatest.com) wrote:
: >I was also sceptical about the amps being built in the far-east
: >  or where-ever.  But if you look in the amp and see what components
: >  they use and how it was designed, you can easily see why the
: >  amplifiers sound so brilliant.

: Good point...also, I wouldn't be surprised that the components
: they use off-shore are of inferior quality.  As long as it was
: properly designed and robust, premium components are used, it
: shouldn't matter where it is assembled.

Definately, I agree wholeheartedly.  If they can build the amp where
  the labour is not so expensive, they can afford to put decent
  components in and go to more effort to improve the design of the
  amplifier - as Adcom has done.

: >I cannot see why people say the amplifier won't last - not with
: >  those quality components inside.  Sure the amp runs very fairly
: >  hot - but that's how you get an amp to sound incredibly good.

: An amp that runs hot has no bearing on how it's gonna sound.
: The amp you have probably is running Class-A the whole day.

: Actually, I'd be wary of excessively hot amps, 'cauz even though
: the components inside may be rated to run that way, excessive 
: heat will dramatically shorten the life of *any* electronic component
: regardless of quality.  In fact, an amp that does run hot to the touch is
: because either the engineer or manufacturer of that amp wanted
: to skimp on heatsinking or cooling to save costs!  Hmmmmm....

Sure, I didn't mean to imply that because of the heat generated, the
  amp sounds good.  My Adcom GFP 535II runs fairly warm - not hot to
  the touch - but enough to satisfy me that the amp is running nicely.
I don't like it when an amp runs dead-cold.  It makes one think that
  the amp is doing nothing :)
The heatsinks that Adcom uses in their amps are certainly far for
  skimpy - they're massive things with heating vents both below
  and above.  More than enough to carry away excessive heat.

My opinions once again.

--
***********************************************************************
**    Alan Webber                                                    **
**                      webb@itu1.sun.ac.za                          **
**                      webb@itu2.sun.ac.za                          **
**                                                                   **
** The path you tread is narrow and the drop is sheer and very high  **
** The ravens all are watching from a vantage point near by          **
** Apprehension creeping like a choo-train up your spine             **
** Will the tightrope reach the end; will the final couplet rhyme    **
***********************************************************************

Newsgroup: sci.electronics
Document_id: 53726
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: What's a good IC for RS232 -> TTL signals??

In article <C5nz60.99z@scraps.uucp>, frankh@scraps.uucp (Frank Holden KA3UWW) writes:
> In <C57zsC.9FL@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:
> 
>>I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
>>levels.  Something relatively inexpensive would be nice, too.  Anyone have
>>a suggestion??  Thanks.
> 
> Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
> you want.  They are selling it for about $3.50...
 
Digi-Key also sells Quad Line Receivers, parts DS1489AN (68cents) and DS1489N
(48cents).  A Quad Line Driver, part DS1488 (48cents), is also sold.  I guess
if you don't won't to supply +12V, the chips with the pump-up circuitry might
be worth the extra cost.  But 1488's and 1489's are available at your friendly
neighborhood RS, parts MC1488 (276-2520) for $1.29 and MC1489 (276-2521) for
$1.29.
 
Jeff White          jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
Document_id: 53727
From: conrad@spva.ph.ic.ac.uk (Conrad Winchester)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu>, st1my@rosie.uh.edu (Stich, Christian E.) writes:
-| I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
-| 68030 + 68882 with capability to clock the FPU separately).  Previously
-| a MC68882RC25 was installed and everything was working perfectly.  Now the
-| systems displays a yellow screen (indicating a exception) when it check for
-| the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
-| fine, but with the XC68882 even at 25 MHz it does not work.  The designer
-| of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
-| might help, but that didn't change anything.  Does anybody have some
-| suggestions what I could do?  Does this look like a CPU-FPU communications
-| problem or is the particular chip dead (it is a pull, not new)?
-| Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
-| that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
-| Are there any MC68882RC33?
-| 
-| Thanks
-| 	Christian 
-| 


             Have you changed the crystal that clocks for the FPU. If you
   haven't then it won't work.


               Conrad

Newsgroup: sci.electronics
Document_id: 53728
From: agodwin@acorn.co.uk (Adrian Godwin)
Subject: Re: Single chip receiver for FSK?

In article <C5L0xM.E25@law7.DaytonOH.NCR.COM> jra@law7.DaytonOH.NCR.COM (John Ackermann x 2966) writes:

>My goal is to come up with an inexpensive design for a receiver "back
>end" with IF input on one end and an FSK demondulator on the other.  I'm
>particularly interested in ways to use a higher IF than 10.7 -- do any
>current chips work up to, say 150MHz with internal downconversion so a
>normal IF filter can be used?
>

GEC/Plessey specify a series of FM demodulators (SL1454 etc) for use in
satellite TV receivers : 150 or 600MHz in, 10MHz of baseband video out.
I think there's also a related data slicer / clock recovery circuit intended
for use in DMAC decoders, though that isn't used in the most common 
implementation - it may not be in volume production.

The most easily available components probably vary with local satellite
standards, and I think the european systems vary rather widely from those
in the US - so it may be worth investigating locally-available receiver
designs to find out what's in common use.

-adrian


-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.

Newsgroup: sci.electronics
Document_id: 53729
From: andrei@labomath.univ-orleans.fr (Andrei Yakovlev)
Subject: References to switched-capacitor filter ICs wanted.


   Hi All!

   I would like to know what are the popular ICs of the type, their capabilities
(# of channels et.c.) and prices :-)

   Great thanks,

 Andrew.

Newsgroup: sci.electronics
Document_id: 53730
From: bills@inqmind.bison.mb.ca (Bill Shymanski)
Subject: Re: Dmm Advice Needed

kolstad@cae.wisc.edu (Joel Kolstad) writes:

> In article <734953838.AA00510@insane.apana.org.au> peter.m@insane.apana.org.a
> >
> >If you are going to use one where it counts (eg:aviation, space scuttle, 
> >etc) then I suggest you go and buy a Fluke (never seen a Beckman), however 
> >for every other use you can buy a cheapie.
> 
> My Beckman died a few days ago, thanks do about a 4 or 5 foot drop onto a
> lab table.  !@#!@$#!@$@#$  Probably not indicative of anything, but I've
> already filled out the requisition for a Fluke 87. :-)
> 
> Oh yeah, and sometimes our measurements here do count.  Not often, but often
> enough that I want at least _one_ good meter!
> 					---Joel Kolstad
   
We used to buy Beckman 110 and HD110 ("ruggedized") versions for use
by electricians in the steel mill where I work.   After a while we
got round to filling all the current-input jacks with silicone -
electricians have a regrettable habit of not checking where the last
guy left the leads before using a 3 1/2 digit 0.5 % autoranging $400
meter to check if a fuse is good or not. Its very hard on meters
(and electricians) when you put the milliamp shunt across a 600 volt
bus. 
  But that's not why we stopped buying Beckmans - after a while a 
lot of them got "funny" in the LCD display.  A black stain would
spread from one edge, or else they'd come adrift from those
Zebra connectors and fail to operate.    Now we buy Flukes, the
low-end 20 series mostly ( and we still fill the amp jack with 
silicone). 
  What the world needs is a meter that won't let you change ranges or
turn it on/off with a lead stuck in the amps jack - a little bit of
clever plastic detailing would take care of this and make the world
safer for electricans, anyway.
   Not that I've ever put a meter on the wrong range into a live 
circuit, no, not me...not more than a dozen times, anyway....
    Bill


bills@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 53731
From: mdgoodma@apgea.army.mil (Malcolm D. Goodman <mdgoodma>)
Subject: Sale -- Fiber Optic Modems, RF Modem, etc -- Best Offer


PLease take these and use them.  Take advantage of me... I really
don't know what they are worth.

Qty 2  -  Canoga Perkins Fiber Optic Modems, Model 2250, RS-422
          Interface, appear new.  I have powered up but that's all,
          I have not used them and I cannot tell you whether they
          work or not.    
                                 Make Offer.........

Qty 1 -   ISC Datacom RF Modem, Model 1056-TX1-RX5-SM-120, Interface
          RS-449, Internal Fan, powers up fine but otherwise condition
          unknown, Phone # for the company is 408-747-0300.

                                 Make Offer ............

Qty 1 -   Motorola UDS  212 A/D  Modem, RS-232 interface appears to work
          but I have not and cannot check it.  

                                 Make Offer  .............

Thanks and please buy this stuff or it goes out the door

Mack
mdgoodma@cbda8.apgea.army.mil
.

Newsgroup: sci.electronics
Document_id: 53732
From: krouth@slee01.srl.ford.com (Kevin Routh)
Subject: F.Y.I.: ImageWriter to Windows...

[ Article crossposted from comp.windows.ms ]
[ Author was Kevin Routh ]
[ Posted on 19 Apr 1993 12:35:55 GMT ]

For your information:

I hooked up my ImageWriter I to my COM1 serial port and used the C-Itoh
8510 driver in Windows 3.1.  The cable I am using is a straight-thru
cable connected to a Null Modem Adapter I got at Radio Shack (catalog
#26-1496a) for $4.95.  It seems to work fine with both DOS and Windows.
I used the following command in DOS

	C:\DOS\mode COM1:9600,n,8,1,p

and set up the port the same way in the Windows Ports setup.

the Null Modem connections are as follows:

	1	to	1
	2	to	3
	3	to	2
	4	to	5
	5	to	4
	6+8	to	20
	20	to	6+8
	7	to	7

I printed from several applications and all seems OK.  

-- 
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244



--
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244


--
Kevin C. Routh                     Internet:    krouth@slee01.srl.ford.com
Ford Electronics                   IBMmail (PROFS):               USFMCTMF
ELD IC Engineering
17000 Rotunda Drive, B-121         Voice mail:              (313) 337-5136
Dearborn, MI  48121-6010           Facsimile:               (313) 248-6244


Newsgroup: sci.electronics
Document_id: 53733
From: sean@dip1.ee.uct.ac.za (Sean Borman)
Subject: INFO WANTED : Graphics LCD displays


Hi there

Does anyone know how to get hold of data as well as stock of the
LCD displays used in the NINTENDO GAMEBOY handheld TV game machines?

Any information wouold be MOST appreciated.

Please e-mail any replies to 

arawstorne@eleceng.uct.ac.za

thanks

Alex

Newsgroup: sci.electronics
Document_id: 53734
Subject: PACE MODEM 
From: mora@verdi.cineca.it (Stefano Mora)

Hi,
I've got a PACE MODEM , Series Four 2400s ( made in England by
PACE Micro Technology ) with a broken power supply .
So I'd like to know :

- the voltage and current values of the original 
  power supply PS1001.
- the pinout of the power supply connector.
- the pinout of the USER PORT and how to use it.

Many thanks in advance to all the people help me.
Please post the reply also to my e-mail..........

+--------------------------------------------------+
|                                                  |
|  Sender: Stefano Mora                            |
|  eMail : mora@verdi.eng.unipr.it                 |
|                                                  |
+--------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53735
From: gould@waterloo.hp.com (Dan Gould)
Subject: Telephone Controlled Power Bar Needed

I would appreciate some help in locating a telephone controlled power bar
for my PC. The unit would power up the PC when the telephone rings and
keep it up as long as the telephone connection is present.

I also need to be able to power up this same PC through the use of an external
timer. I can supply power or a contact closure to do this.

I will summarize and post the results of this query here.

Thank you.



--
Dan Gould
gould@waterloo.hp.com

Newsgroup: sci.electronics
Document_id: 53736
From: kehoe@netcom.com (Thomas David Kehoe)
Subject: Re: How starters work really

>>So when you turn on the power, this causes the bulb to work like a neon, 
>
>Imprecise. This description
>
> 1. ignores the role of the ballast,
> 2. misrepresents the heating effects in the starter.
>
>The bimetalic strip cools down immediately after the contacts

I've been thinking of sending into Mad magazine an idea for a 
parody, of those books entitled "How Things Work" that
engineers buy their sons, which explain how engines, elevators,
flourescent lights, etc. work.

The parody would be "How Things Really Work."  Under "Canned
Food", on the left page you'd see the description from 
"How Things Work": gleaming stainless steel equipment
pasteurizing the food to precisely the right temperature,
then sealing the can in an oxygen-free environment, etc.

On the right page you'd see "How Things Really Work":
brain-dead workers sending disgusting food to the
gleaming equipment -- rotting vegetables, parts of
animals people don't eat, barrels of sugar and chemicals.

Under "Elevators" you'd see (on the left) computer geniuses
working out algorithms so that X number of people
waiting for Y elevators will get to Z floors in the shortest
time.  On the right, you'd see giggling elevator controllers
behind a one-way mirror in the lobby choosing which people
appear to be in the biggest hurry and making them wait longest.
-- 
"Why my thoughts are my own, when they are in, but when they are out
they are another's." - Susannah Martin, hanged for witchcraft, 1692.
Thomas David Kehoe          kehoe@netcom.com         (408) 354-5926

Newsgroup: sci.electronics
Document_id: 53737
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: History question

In article <2775@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:
>
>I recall reading of a phonograph which used mechanical amplification.
>Compressed air was squirted out of a valve which was controlled by the
>pickup.  The result was noisy and distinctly lo-fi, but much louder
>than a conventional phonograph.  It tended to wear the disks out
>pretty quickly though.

This was the Pathe you are thinking of, although there were other imitators.
It didn't wear the disks any more than conventional acoustic designs, but
it did have a high noise level due to the continual hiss of escaping air.
There are a lot of them still operating, and they are pretty ingenious.

There was a pneumatic amplifier designed by Alexander Graham Bell, as well,
but I don't know if it was ever constructed.
--scott

Newsgroup: sci.electronics
Document_id: 53738
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?


Call a friend long distance, collect.  Ask to speak with yourself.  When
the operator asks for you, you won't be there, so ask the operator to leave
your number.  She'll read it out in the clear.
--scott

Newsgroup: sci.electronics
Document_id: 53739
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: subliminal message flashing on TV

In article <7480237@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> Hi.  I was doing research on subliminal suggestion for a psychology
>> paper, and I read that one researcher flashed hidden messages on the
>> TV screen at 1/200ths of a second.  Is that possible?  I thought the
>> maximum rate the TV was even capable of displaying images was 1/30th
>> of a second.  (or 1/60th of a second for an image composed of only odd
>> or even scan lines)
>
>You are correct; the fastest "complete" image that could be presented on
>TV would be one field, which is 1/60 of a second (approximately).  Of course,
>the phrase "TV screen" is often thrown around in reference to any CRT
>display, so perhaps this researcher wasn't using normal TV rates.  Might
>even be a vector ("strokewriter") display, in which case the lower limit
>on image time is anyone's guess (and is probably phosphor-persistence limited).

Actually, a lot of this work used to be done with a CRT that had a beamsplitter
mounted in front, and a tachistoscope driving it.  The tachistoscope is really
just a slide projector with a very fast shutter.  Low tech, but it does the job.
--scott

Newsgroup: sci.electronics
Document_id: 53740
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Mysterious MOSFET

I have a MOSFET pulled out of a Trygon power supply, for which I have no 
manual.  It's a Motorola part with a 1972 date code and the number

		285-4

which the Motorola folks assure me is a house number, which they can't
help me with.  Any suggestions from folks out there?  I can't put it on
a curve tracer to try to get an equivalent, since it's completely shot.
--scott

Newsgroup: sci.electronics
Document_id: 53741
From: bakerjp1@netnews.jhuapl.edu (Baker John P. PDD x4895 )
Subject: How does "Differential Mode" GPS work???


>I understand that the new GPS boxes now have an option
>known as "differential ready".  Apparently land-based
>beacons tranmit GPS correction information to your GPS 
>receiver (with differential option installed).

>How does this system work?  What frequency is used for
>the land-based beacons?

>Thanks in advance,

>Charlie Thompson
>.

Here's a rough sketch of how the system works.  A reference station
with a very exactly known position computes the errors in the
incoming GPS signals.  These errors are due to several factors
including atmospheric distortion, SA (Selective Availability) time
dithering, etc.  The reference unit contains complex computational 
equipment to "back out" the errors in its position (since it knows
where it is already).  It then transmits these corrections on a 
broadcast which is available to any number of relatively local
receivers.  If the receivers are nearby (<300km) and are using
the same satellites as the reference unit, the errors should be very
similar for the reference unit and the receiver unit.  Thus, the
receiver unit may apply the corrections calculated by the reference
unit.

The US Coast Guard is currently (as far as I know) installing a series
of coastline transmitters for differential GPS.  These stations will
use existing radio towers.  I believe the frequency is to be approximately
305 kHz.  There are many other private corporations offering DGPS signals
on different frequencies.  For example, PinPoint ((310)-618-7076) offers
correction signals and receiver units using an FM broadcast system
which has stations all across the US.

The correction codes are usually transmitted using the RTCM 104 format.
Advertised accuracies espouse 1 to 5 meter errors.


-------------------------------------------------------------------------
John P. Baker                   | My opinions are my own.  I don't know
Johns Hopkins University        | anyone else who wants them, anyway.
Applied Physics Laboratory	|
Laurel, MD  20723               | bakerjp1@aplcomm.jhuapl.edu
--------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53742
From: mjhill@eos.ncsu.edu (MICHAEL JAMES HILL)
Subject: New applications of electronics



	I'm looking for brief information on new
applications of electronics (or new electronics in
applications.) If you know of any interesting new
stuff, I would be intrested in hearing about it.

			Thanks, MJH

Newsgroup: sci.electronics
Document_id: 53743
From: domain@cbnewsf.cb.att.com (george.d.hodge)
Subject: Dayton Hamfest


Some weeks ago, someone posted an article telling when and where
a hamfest and computerfest was going to be help in Dayton, OH.
Unfortunately, I lost the article and I was wondering if someone
could repost it.

I believe it was being held the 23,24,and 25 of this month at
the Dayton convention center but I'm not sure.

Any help and more details would be greatly appreciated.

		george.d.hodge
		domain@cbcat.att.com


Newsgroup: sci.electronics
Document_id: 53745
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: What do Nuclear Site's Cooling Towers do?

> I really don't know where to post this question so I figured that
> this board would be most appropriate.

try sci.energy

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
Document_id: 53746
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: 16 bit serial converters

Someone was looking for these a few weeks ago - check out comp.dsp
Mike.

Newsgroup: sci.electronics
Document_id: 53747
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Getting rid of screen wiggles?

In article <1qpj5t$itg@vela.acs.oakland.edu>, eabyrnes@vela.acs.oakland.edu
(Ed Byrnes) wrote:
> 
> My monitor display has a bad case of the wigglies. I have a good ground. I
> live in an old house and I have replaced much of the wiring. I have two
> EMI filters on the computer, the monitor plugs into the computer. When
> fluorescent lights are on upstairs, the display jiggles, when motors run
> in the house, the display jiggles, when incandescent lights are on in the
> kitchen the display jiggles.  I could bring a separate line from the
> breaker box, and use it only for the computer, would this do it? EMI
> doesn't only travel the 110 volt line though. Should I shield the back of
> the monitor? Ground a grid or plate? 
> Your expertise is appreciated. Thanks very much!  Ed Byrnes


Aaahh... a problem very near and dear to my heart. In our case, other
monitors cause this problem - the deflection coil of other monitors to be
specific. Have also seen a monitor backed up to a fuse panel exhibit this
problem. This sounds like your problem since flourescent lites, motors, etc
several 10s of feet away seem to me to be too far to cause it, but the
juice running to them must pass nearby your monitor. Fusebox on other side
of wall maybe?
We started spec'ing Panasonic CT-1331Y video monitors (3 switchable input
lines(vid & aud) S-VHS on one) <$400. This stopped the wavy interference
effect on the computer monitor next to it. 
Now on to your problem. You need what is known as mu shielding (very
common, in fact almost mandatory on electrostatic deflection type
O'scopes).
I talked to a EE prof. He said get a coffee can, cut both ends off, mount
around deflection coil of interfering monitor. 
BE CAREFUL TO AVOID ALL HIGH VOLTAGE CIRCUITRY. ESPECIALLY THE THICKER HIGH
VOLTAGE ANODE LEAD USUALLY COLORED RED. IF YOU KILL YOURSELF, DON'T
BLAME/SUE ME!!! USE PLASTIC OR OTHER NON-CONDUCTING STAND-OFFS AND SUCH TO
MOUNT CAN.
Now, I would assume that what is good for keeping mag fields in is also
good at keeping them out, so hopefully this'll work by mounting shield on
monitor being interfered with as well. If not, start shielding those other
sources.

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
Document_id: 53748
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Food Dehydrators

  Does anybody out there have one of those food dehydrators I've been seeing
all over late-night TV recently? I was wondering if they use forced air, heat,
or both. If there's heat involved, anybody know what temperature they run at?
My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
and a heater. Seems to me you should be able to throw a dehydrator together
for just a few bucks. Heck, the technology is only what? 1,000 years old?

John


Newsgroup: sci.electronics
Document_id: 53749
From: ski@wpi.WPI.EDU (Joseph Mich Krzeszewski)
Subject: Re: Need to find out number to a phone line

Well, this is my second try at posting on this subject. Here goes...
	In Texas (Corpus Christi at least) if you pick up the phone and dial
	890 the phone company will read the number of the phone you are on 
	back to you. I believe the service department uses this to make
	certain they are repairing the correct lines when they open the BIG
	junction boxes. I don't know if it will work but you can give it a
	try. Good luck.
 


Newsgroup: sci.electronics
Document_id: 53750
From: billq@ms.uky.edu (Billy Quinn)
Subject: Suggestions  on Audio relays ???

I built a little project using the radio shack 5vdc relays to switch
audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
most of the common things one is supposed to do when using relays and
nothing seemed to get rid of the clicks.


My question is:

	Is there a good relay/relay circuit that I can use for switching
audio, so that there will be *NO* noise of any kind on the audio lines.


I will appreciate any advice or references to advice.  Also, exact part
numbers/company names etc. for the relays will help!

Thanks!


-- 
*-----------------------------------------------------------------------*
*	Bill Quinn			billq@ms.uky.edu		*
*-----------------------------------------------------------------------*

Newsgroup: sci.electronics
Document_id: 53751
From: levy@levy.fnal.gov (Mark E. Levy, ext. 8056)
Subject: Re: What do Nuclear Site's Cooling Towers do?

In article <1qngqlINNnp8@shelley.u.washington.edu>, whit@carson.u.washington.edu (John Whitmore) writes:
> In article <C5L5x0.KJ7@vcd.hp.com> johne@vcd.hp.com (John Eaton) writes:
>>-s87271077-s.walker-man-50- (swalker@uts.EDU.AU) wrote:
> 
>>During the nuclear fission reaction the uranium fuel can get hot enough
>>to melt. When this happens the liquid uranium is pumped to the cooling
>>tower where it is sprayed into the air. 
...
>>Contact with the cool outside air
>>will condense the mist and it will fall back to the cooling tower floor.
>>There it is collected by a cleaning crew using shop vacs and is then
>>reformed into pellets for reactor use the next day.

Another April 1 posting.  Ahhh.

================================================================================
[ Mark E. Levy, Fermilab          |                                            ]
[ BitNet:   LEVY@FNAL             | Unix is to computing                       ]
[ Internet: LEVY@FNALD.FNAL.GOV   |       as an Etch-a-Sketch is to art.       ]
[ HEPnet/SPAN: FNALD::LEVY (VMS!) |                                            ]
================================================================================


Newsgroup: sci.electronics
Document_id: 53752
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr14.181738.18472@bmers95.bnr.ca> alee@bmerh794.bnr.ca (Louis Leclerc) writes:
>
> In article <34263@oasys.dt.navy.mil> you write:
> >VA, CT, Wash DC  and I think BC Canada where I've heard they actually
> >use Radar detector detectors.
>
> Nope, not in British Columbia.  Detectors are legal here in BC, I've even
> got one.
>
> In Alberta and Ontario they're illegal, and detection devices are sometimes
> used.  I've heard the police in Ontario prefer a much more direct method of
> detection.  Just trigger the radar gun, watch for people slamming on the
> brakes, and search the car.
>
>
> David Lee
> leex@sfu.ca
>

Detectors are legal in Alberta, the old law was overturned a long time ago.

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
Document_id: 53753
From: harton@owlnet.rice.edu (Tracy Brian Harton)
Subject: Wireless Transmitter/Receivers at RS


Does anyone know what frequencies the wireless transmitter/receiver
microphone systems that Radio Shack sells operate at?  I've tried
everything short of opening one up (not actually owning one makes
this difficult...) and just looking..  Any help would be greatly
appreciated..  These systems are designed for wireless PA systems, etc..
 
 
					Thanks,
	 
							Tracy


Newsgroup: sci.electronics
Document_id: 53754
From: st1my@rosie.uh.edu (Stich, Christian E.)
Subject: Re: Motorola XC68882RC33 and RC50

In article <16APR199323531467@rosie.uh.edu>, st1my@rosie.uh.edu (Stich, Christian E.) writes...
>I just installed a Motorola XC68882RC50 FPU in an Amiga A2630 board (25 MHz
>68030 + 68882 with capability to clock the FPU separately).  Previously
>a MC68882RC25 was installed and everything was working perfectly.  Now the
>systems displays a yellow screen (indicating a exception) when it check for
>the presence/type of FPU.  When I reinstall an MC68882RC25 the system works
>fine, but with the XC68882 even at 25 MHz it does not work.  The designer
>of the board mentioned that putting a pullup resistor on data_strobe (470 Ohm)
>might help, but that didn't change anything.  Does anybody have some
>suggestions what I could do?  Does this look like a CPU-FPU communications
>problem or is the particular chip dead (it is a pull, not new)?
>Moreover, the place I bought it from is sending me an XC68882RC33.  I thought
>that the 68882RC33 were labeled MC not XC (for not finalized mask design). 
>Are there any MC68882RC33?
> 
>Thanks
>	Christian 
> 

It appears as if the problem is related to the 68882/50's need for very fast
(and clean) signal transitions.  I got some email (Vielen Dank, Thomas) stating
that Motorola provides a solution for this problem in their 68030 manual.  
Since my manual (1989) predates the 50 MHz 68030/68882s I couldn't find it.
Could someone please email me the specifics?
		Thanks
			Christian

Newsgroup: sci.electronics
Document_id: 53755
From: mont@netcom.com (Mont Pierce)
Subject: Re: 8051 Microcontroller

In article <1qppr5INNaqa@dns1.NMSU.Edu> mcole@spock (COLE) writes:
>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>there know of any good FTP sites that might have compiliers, assemblers,  
>etc.?

Well, it's not an FTP site, but I got an 800 number for Signetics BBS.

The Signetics BBS contain some pretty good items for the 8051.  I am
currently using the following files which I downloaded from them:

    ml-asm51.zip      MetaLink's 8051 family macro assembler
    bootstrp.zip      Hex file Load-and-Go using 8051 uart
                      (allows you to download your program into a RAM
                       and then execute from RAM.  Works great.  Tell
                       me if you want more details).
    tutor51.zip       TSR for 8051 feature help screens
    
They have lots of coding examples, assemblers, and misc. tools.

Signetics BBS numbers are:    (800) 451-6644
                              (408) 991-2406

Have fun,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53756
From: borowski@spk.hp.com (Don T. Borowski)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

Dean Anneser (anneser@pwa-b.uucp) wrote:
: My 9 yr old son has signed up to do a science report on batteries.  I was
: wondering if anyone could provide me with some information as to how to
: construct a home-built battery.  In my grade school days, I remember seeing
: the 'ice cube tray' version, but I don't remember what to use as a good
: electrolyte or what the easily obtainable metals were.  
: 
: Thank you in advance.
 
I remember watching a whole "Mr. Wizzard" program on this subject when
I was a kid.  The battery constructed on the program which made the 
biggest impression on me, and generated the most power, was made using
a galvanized bucket (for the zinc) and a copper toilet tank float.  The
electrolyte was sauerkraut!


Donald Borowski    WA6OMI    Hewlett-Packard, Spokane Division
"Angels are able to fly because they take themselves so lightly."
                                       -G.K. Chesterton


Newsgroup: sci.electronics
Document_id: 53757
From: mont@netcom.com (Mont Pierce)
Subject: Need pinouts for a G8870 dtmf decoder chip


I bought this chip from Suncoast Technology and tried to build their
dtmf decoder circuit.  But it's not working...

If anyone has the pinouts and possibly the voltage specs I'd sure
appreciated it.  If someone could fax, email, or snail mail a copy
of the spec sheet for this chip that would be even better. :)

Please email me if you can help.  

Thanks in advance,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53758
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Cicuit Cellar Ink - Extras 4 Trade

Fellow Info-junkies,
  I have an extra CCI #27 (Real Time Programming/Embedded Sensors &
Storage) and an extra CCI #32 (Voice control of telescope, among other
articles). No labels. No torn, cut-up, or missing pages.

Would like to trade for CCI # 26, or CCI # 23, or CCI # 19 in same
condition (Labels OK).

I mail mine you mail yours mutual trust kinda thang OK?
You don't actually throw them away, do you?

Thanx,
Jeff Babb
babb@sciences.sdsu.edu

Newsgroup: sci.electronics
Document_id: 53759
From: garyg@warren.mentorg.com (Gary Gendel)
Subject: Re: Need to find out number to a phone lin

In article 1qub4mINN7r3@rave.larc.nasa.gov, kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>>
>>Greetings!
>>      
>>        Situation:  I have a phone jack mounted on a wall.  I don't
>>                    know the number of the line.  And I don't want
>>                    to call up the operator to place a trace on it.
>>
>>        Question:   Is there a certain device out there that I can
>>                    use to find out the number to the line?
>
>
>Call a friend long distance, collect.  Ask to speak with yourself.  When
>the operator asks for you, you won't be there, so ask the operator to leave
>your number.  She'll read it out in the clear.
>--scott

Even easier, my area supports 311.  Dial this and a recording recites your number.
Phone techs use it to verify an installed line.
---
			Gary Gendel
Vice President:				Current consulting assignment:
Genashor Corp				Mentor Graphics Corporation
9 Piney Woods Drive			15 Independence Boulevard
Belle Mead, NJ 08502			Warren, NJ 07059

phone:	(908) 281-0164			phone:	(908) 604-0883
fax:	(908) 281-9607			email:	garyg@warren.mentorg.com




Newsgroup: sci.electronics
Document_id: 53760
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does someone know what is the news group for IEEE.

       yxy4145@usl.edu     Thanks a lot.


Newsgroup: sci.electronics
Document_id: 53761
From: khairon@usc.edu (Rosli Bin Khairon)
Subject: Looking for Address of Noise Cancellation Tech.

      I am new to this newsgroup so I apologise if this is not the appropriate
forum to ask this question. I am looking for the address of Noise Cancellation
Technologies. It is rather important. So if you can help me in this regard,
please do. Thank you.



    




-- Rosli
Khairon@aludra.usc.edu

Newsgroup: sci.electronics
Document_id: 53762
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Motorola XC68882RC33 and RC50

In article <sgberg.23xu@charon.bloomington.in.us> sgberg@charon.bloomington.in.us (Stefan Berg) writes:
>... I don't know why my FPU has an XC (my original 33MHz FPU
>was label MC68882-33), but it seems to work fine on my system...
>P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)

The rule for the designations is that if it says MC, that means it works
*exactly* the way the datasheet/book specifies.  If it says XC, that means
there is at least one known bug.  Often these bugs are small and obscure;
you might never run into them in practice.

At least Motorola admits it, unlike certain other companies...
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53763
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: Mysterious MOSFET

In article <1qug3sINN90g@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:

>I have a MOSFET pulled out of a Trygon power supply, for which I have no 
>manual.  It's a Motorola part with a 1972 date code and the number

>               285-4

>which the Motorola folks assure me is a house number, which they can't
>help me with.  Any suggestions from folks out there?  I can't put it on
>a curve tracer to try to get an equivalent, since it's completely shot.
>--scott
Since your MOSFET is a 1972 vintage, it's probably not a very good one by 
today's standards.  If you have an idea about its voltage and current 
ratings, e.g. 60VDC @ 6A, you can probably get away with replacing it with 
anything with better specs.  Early MOSFETS had a gate-source voltage rating 
of approximately +/- 20 VDCmax, and they would usually turn completely "ON" 
at +10VDC.  Otherwise, MOSFETS are not really mysterious -- they're more or 
less voltage controlled current sources.  If the MOSFET in your circuit is 
used as an open-loop, voltage controlled current source, you may have to 
experiment with various gain-altering techniques.

Bill Willis     willisw@coe-nw.clemson.edu
(803) 656-5550

Newsgroup: sci.electronics
Document_id: 53764
From: kubovich@iastate.edu (Mark W Kubovich)
Subject: Common-mode noise and small signals

I have never worked with really small signals before and have a few 
questions about low level noise.  I have noticed that the waveform 
synthesizer that I am using (Analogic 2020) has some relatively large
common mode noise on it.  I am using this synthesizer to 'null' out another
transient waveform and am amplifying the difference (~200uV) several hundred 
times.  The 2020 has about 1-3 mVp-p of common mode noise and this tends to
make my measurements hard to repeat.  (The noise is not quite in sync with 
line frequency, and on a spectrum analyzer, the main component is about 64Hz).

How can I get rid of the noise?  When I look at the spectrum using an
HP 3582A (audio range analyzer), the noise goes away the minute I switch to 
'isolation' on the input.  I am guessing the anlayzer has a diff amp on the 
input since it will read accurately down to DC.

Also, if I use a differential amplifier (IA) to solve the problem, 
how important is it to use one of these 'shield drivers' (an amp connected 
to the shield in sort of a feedback loop to remove trouble caused 
by different cable capacitances)?  If anyone can suggest a good IC IA for 
use with transient signals with content from 1KHz to about 300KHz, I would
appreciate it.  

Newsgroup: sci.electronics
Document_id: 53765
From: bday@lambda.msfc.nasa.gov (Brian Day)
Subject: Re: 8051 Microcontroller

mcole@spock (COLE) writes:

>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>there know of any good FTP sites that might have compiliers, assemblers,  
>etc.?

Try lyman.pppl.gov -- /pub/8051

-- 
Brian Day                                       bday@lambda.msfc.nasa.gov
New Technology, Inc.                            (205) 461-4584
Mission Software Development Division           Opinions are my own -

Newsgroup: sci.electronics
Document_id: 53766
From: Wayne Alan Martin <wm1h+@andrew.cmu.edu>
Subject: Re: Dayton Hamfest

Yes, it is the 23, 24 and 25, in but does anyone have directions how to
get there after I get to Dayton.  Thanks

Wayne Martin


Newsgroup: sci.electronics
Document_id: 53767
From: jkaidor@synoptics.com (Jerome Kaidor)
Subject: Re: electronic odometers (was: Used BMW Qu


    Just a few comments about the feasability of zipping up a bunch of miles
on your electronic odometer with an oscillator....

    I wouldn't expect to be able to do this.  Not because the engineers at BMW are
putting in anti-fraud logic, but just because an automobile is a noisy, hostile
environment for electronics, and I would expect the software to be conservative.

   If I were to design a microprocessor-based odometer/speedometer program,
it would have the following features ( just off the top of my head ):

         * Debouncing/deglitching  ( Is this a real pulse, or just a glitch? )
         * Smoothing:  The rate-of-change of speed cannot be too high:
                                This is a car, not an electron.
         *  Top speed limit:  Anything above 200MPH is ridiculous: must be
                                        electrical noise or contact bounce

    As for getting in and presetting the pins:  if this is the circuit board out of
a BMW dashboard, I seem to remember a single big chip with lotsa pins in the
middle of the card.  Good luck getting at the counter :-).

    I wouldn't expect a high input frequency to damage the meter:  remember, it's
probably damped so it can't move too fast, and is probably protected.  After all,
a car is an extremely hostile place for delicate electronics;  there used to be an
app note in the National Semiconductor Linear Databook that went into this
in good detail.

                               - Jerry Kaidor ( tr2!jerry@dragoman.com, jkaidor@synoptics.com )


                                  - Jerry Kaidor

Newsgroup: sci.electronics
Document_id: 53768
From: 2575brooksr@vms.csd.mu.edu
Subject: NeXT cube board monitor cable ?

Hi all!
	Quick question.  Could someone please send me a pinout of
the cable that goes between a NeXT cube and the monitor?  Also,
I am interested in the video signal (sync type, horz/vert rate)
so any information on that would be greatly appreciated also.

Thanks!
Ryan Brooks					ryan@agnus.mcs.mu.edu

Newsgroup: sci.electronics
Document_id: 53769
From: alung@megatest.com (Aaron Lung)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al

There is a number you can call which will return a synthesized
voice telling you the number of the line.  Unfortunately, for the
life of me I can't remember what it is. The telephone technicians
use it all the time.  We used to play around with this in our
dorm rooms since there were multiple phone lines running between
rooms.

sorry!

aaron


Newsgroup: sci.electronics
Document_id: 53770
From: musone@acsu.buffalo.edu (Mark J. Musone)
Subject: MC SBI mixer

HI, I was wondering if anyone would be able to help me on twwo related
subjects. I am currently learning about AM/FM receivers and recieving
circuits. I understand a lot of things ,but a few things I am confused
abuot. The first is the MIXER, to mix the RF and local oscillator
frequencies to make the IF. Does anyone have any cicruit diagrams (as
simple as possible) for this kind of mixer? I have come across a
MC-SBL mixer chip But I have not been able to find it in any catalogs
(ACTIVE,etc...) 

Along the same note, are there any SIMPLE fm receiver circuits anyone
may have stashed away somewhere and they couold let me see?.

P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
ELECTRICAL DIAGRAMS would help a lot.
I have seen a lot of theory books with no circuits and a lot of
circuit books with no theory, but one without the other does not help.

				Thanks,

				Mark Musone

Newsgroup: sci.electronics
Document_id: 53771
From: levy@levy.fnal.gov (Mark E. Levy, ext. 8056)
Subject: Sources for Intel D87C51FB?

I am in the midst of designing a project which requires two motors and an LED
illuminator driven with Pulse-width modulation.  I'm using the 8751, and
I understand that the -FB version has a programmable counter array that can
essentially be set and forgotten to do the PWM.  The problems is, that variant
is difficult to come by.  I need two or three of the D prefix (ceramic window)
version for development, and then lots of the P prefix (plastic OTP) for later
production.  I've tried Avnet, Arrow, and Pioneer.  They (might) have them, but
I'm looking for samples at this point, and they're not too willing to provide
them.  I would buy them, but these vendors have $100.00 minimums.

Any help is appreciated.

================================================================================
[ Mark E. Levy, Fermilab          |                                            ]
[ BitNet:   LEVY@FNAL             | Unix is to computing                       ]
[ Internet: LEVY@FNALD.FNAL.GOV   |       as an Etch-a-Sketch is to art.       ]
[ HEPnet/SPAN: FNALD::LEVY (VMS!) |                                            ]
================================================================================

Newsgroup: sci.electronics
Document_id: 53772
From: jott@scarecrow.cse.nd.edu (John Ott)
Subject: Re: Pinout needed for TIL311

In article <segal.734995860@corolla7>, segal@rtsg.mot.com (Gary Segal) writes:
|> I've recently picked up some TIL311 display chips, but I can't find
|> any information on them.  It seems they are no longer made by TI, and
|> I don't have an old enough data book.  :-(
|> 
|> It appears to have a dot-matrix led display capable of showing one hex
|> digit.  It is in a 14 pin DIP package, but pins 6, 9, and 11 are not
|> present.
|> 
|> If you have any information on this part (pinout, power requirments,
|> functions, ...) please send me e-mail.
|> 
|> Thank You,
|> 
|> -- 
|> Gary Segal                             Motorola Inc.            
|> segal@oscar.rtsg.mot.com               Cellular Infrastructure Division
|> 	--- we are standing here only to gaze at the wind ---


pin      function
 1      led supply voltage
 2      latch data input b
 3      latch data input a
 4      left decimal point cathode
 5      latch strobe input
 6      omitted
 7      common gnd
 8      blanking input
 9      omitted
10      right decimal point cathode
11      omitted
12      latch data input d
13      latch data input c
14      logic supply voltage (5v)

LATCH STROBE INPUT, pin 5, when low, the data in the latches follow the data on the latch data
                             inputs.  When high, the data in the latches will not change.  If the
                               display is blanked and then restored while the enable input is high,
                               the previous character will again be displayed.

BLANKING INPUT, pin 8,    When high, the display is blanked regardless of the levels of the other
                              inputs.  When low, a character is displayed as determined by the data
                              in the latches.  The blanking input may be pulsed for intensity modulation.

LATCH DATA INPUTS, pins 2,3,12,13,   Data on these inputs are entered into the latches when the enable
                                          input is low.  The binary weights of these inputs are A = 1,
                                          B = 2, C = 4, D = 8

DECIMAL POINT CATHODES, pins 4, 10,   These LEDS are not connected to the logic chip.  If a decimal point
                                          is used, an external resistor or other current limiting
                                          mechanism must be connected in series with it.

LED SUPPLY, pin 1            This connection permits the user to save on regulated Vcc current by using
                                 a separate LED supply, or it may be externally connected to the logic
                                 supply (Vcc).

LOGIC SUPPLY (Vcc), pin 14      Separate Vcc connection for the logic chip

COMMON GROUND, pin 7,      This is the vegative termnal for all logic and LED currents except for the
                              decimal points.

John
jott@dickens.helios.nd.edu

Newsgroup: sci.electronics
Document_id: 53773
From: tron@ux1.cso.uiuc.edu (Tron R.)
Subject: modulation over rf

I would like to modulate a 40KHz squarewave over rf. This is for a rf
remote control project. The squarewave has a high of 5 v and low of 0v.

thanks.

tron
-- 
        T
  T     T
  T  T  T
  T  T  T

Newsgroup: sci.electronics
Document_id: 53774
From: morrow@cns.ucalgary.ca (Bill Morrow)
Subject: Need source for old Radio Shack stereo amp chip

Last week I asked for help in getting an old homemade amp working with
my Sun CD-ROM drive. It turns out that the channel I was testing with
was burned out in the amp. The other channel works fine.

So now I need a new amplifier chip. My local Radio Shack no longer
carries components! The chip is a 12 pin SIP (?) labelled with BA5406
and then "502 515" below that.

Does anyone have a source? Thanks,
-- 
Bill Morrow    Clinical Neurosciences, University of Calgary
e-mail: morrow@cns.ucalgary.ca voice: (403) 220-6275 fax: (403) 283-8770 
3330 Hospital Drive NW Calgary, Alberta, CANADA T2N 4N1

Newsgroup: sci.electronics
Document_id: 53775
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In article <C5quI4.4CF@spk.hp.com> borowski@spk.hp.com (Don T. Borowski)  
writes:
> Dean Anneser (anneser@pwa-b.uucp) wrote:
> : My 9 yr old son has signed up to do a science report on batteries.  I  
was
> : wondering if anyone could provide me with some information as to how  
to
> : construct a home-built battery.  In my grade school days, I remember 

(snip!)

I haven't been following this, so I'm sorry if somebody already mentioned  
this, but you could grab a lemon (I think potatoes work too, but I'm not  
sure), a strip of copper, and a strip of zinc (I think you can get the  
metal in a hardware store or hobby shop, maybe??).  Stick the strips in  
the lemon (so they don't touch!) and you'll get a measurable voltage (not  
a lot, but, hey, it's a lemon :-)  ).  As I recall we had to hook  
something like ten of these things to get an appreciable amount of  
current, because of the mondo internal resistance, but if you just need a  
demo you might get it to run a tiny fan or something! :-)


Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
Document_id: 53776
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Need pinouts for a G8870 dtmf decoder chip

In article <montC5qs9A.3wB@netcom.com> mont@netcom.com (Mont Pierce) writes:
>
>I bought this chip from Suncoast Technology and tried to build their
>dtmf decoder circuit.  But it's not working...
>
>If anyone has the pinouts and possibly the voltage specs I'd sure
>appreciated it.  

I presume it is the M-8870 from Teltone Corporation.

Pin	Description

1	+ input
2	- input
3	GS (gain select through use of feed back resistor)
4	Vref (reference voltage OUTPUT, about Vdd/2)
5	connect to Vss
6	connect to Vss
7	osc1 clock input
8	osc2 clock output (connect crystal across pins 7 and 8)
9	Vss
10	OE output enable (logic high allows data output)
11	Q1 data output
12	Q2 data output
13	Q3 data output
14	Q4 data output
15	StD Delayed Steering Output (any other company would call this 'data valid'.)
16	ESt Early Steering output, sort of like "I'm starting to hear a tone".
17	St/GT Steering input/guard time output
18	Vdd

Power Supply	: 4.75V min., 5.25V max.
Current		: 3.0mA Typ, 7.0mA max.

BUT.......

You really should have bought the Motorola part from me.  :-)
(I still have them in stock)

John



If someone could fax, email, or snail mail a copy
>of the spec sheet for this chip that would be even better. :)
>
>Please email me if you can help.  
>
>Thanks in advance,
>-- 
>Mont Pierce
>
>+-------------------------------------------------------------------------+
>| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
>|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
>|    modes: cw,ssb,fm                                                     |
>+-------------------------------------------------------------------------+



Newsgroup: sci.electronics
Document_id: 53777
Subject: Pattern Generator wanted
From: grimwood@ccu1.aukuni.ac.nz (Tony Grimwood)

I repair a lot of monitors here, and I'd like to know where I can get a
pattern generator (or a circuit for one) that will provide MDA, EGA and VGA
signals. Using a whole PC to do this takes up too much space on my bench, and
is somewhat less than portable. I guess I could sit down and design something,
but I don't have the time right now - any (reasonable) suggestions would be
appreciated.

TNX

TG
-- 
Tony Grimwood, ZL1TTG			"Make no friendship with an elephant
Biomedical Engineering Services		 keeper, unless you have room to
University of Auckland			 entertain an elephant."
Auckland, New Zealand		       		 == Saadi of Shiraz ==

Newsgroup: sci.electronics
Document_id: 53778
From: howeg@p4.cs.man.ac.uk (Monty Mole)
Subject: FM Transmitter

Can anyone please email a diagram or give me details of an ftp site where there
is a diagram of a simple, small fm mono voice transmitter for trasnmitting in
the 90-104 range (preferably above 100 Mhz). Only a short distance requiered,
and frequency variation no too important but must run from 9v or smaller DC
supply.

Thanx in advance

Monty.
-- 
    /\    /\     __   __  /_                            howeg@uk.ac.man.cs 
   /  \  /  \   /  / / / /  / /                         howeg@cs.man.ac.uk
__/    \/    \_/__/_/ /_/__/_/____________________________________________
____________________________/ Save The Vinyl!

Newsgroup: sci.electronics
Document_id: 53779
From: alung@megatest.com (Aaron Lung)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>I built a little project using the radio shack 5vdc relays to switch
>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>most of the common things one is supposed to do when using relays and
>nothing seemed to get rid of the clicks.
>
>
>My question is:
>
>	Is there a good relay/relay circuit that I can use for switching
>audio, so that there will be *NO* noise of any kind on the audio lines.
>
>
>I will appreciate any advice or references to advice.  Also, exact part
>numbers/company names etc. for the relays will help!

Are you switching high level signals or low level signals like pre-amp
out level signals?  Also, are the clicks you mentioning the big
clack that happens when it switches or are you refering to contact
bounce?  How are you driving the relays?  TTL gate output?  Switching
transistor?  How are the relays connected to what you are driving?

Need more specifics to answer your question!! :-)

Newsgroup: sci.electronics
Document_id: 53780
From: loving@lanai.cs.ucla.edu (Mike Loving)
Subject: specs on eprom data formats


I need the specs on various eprom data formats such as Intel Hex, Motorola S
JEDEC etc.


Can anyone out there provide such info or a pointer to it?
The one I want the most is Intel Hex.

Mike


Newsgroup: sci.electronics
Document_id: 53781
From: payne@crl.dec.com (Andrew Payne)
Subject: WANTED:  TCM3105 chips, small quantities


Does anyone know if a source for the TCM3105 modem chips (as used in the
Baycom and my PMP modems)?  Ideally, something that is geared toward 
hobbyists:  small quantity, mail order, etc.

For years, we've been buying them from a distributor (Marshall) by the
hundreds for PMP kits.  But orders have dropped to the point where we can
no longer afford to offer this service.  And all of the distributors I've
checked have some crazy minimum order ($100, or so).

I'd like to find a source for those still interested in building PMP kits.
Any suggestions?

-- 
Andrew C. Payne
DEC Cambridge Research Lab

Newsgroup: sci.electronics
Document_id: 53782
From: babb@rapnet.sanders.lockheed.com (Scott Babb)
Subject: Re: Radar detector DETECTORS?

Brian Day (bday@lambda.msfc.nasa.gov) wrote:
: On December 29, 1992, it was illegal to operate a radar detector
: in the state of Virginia.  If one got caught, one got fined $65.00.
: Ask me how I know.

The Federal Communications Act of 1934 made it *legal* for you to
operate a radio receiver of any kind, on any frequency (including
X, K, and Ka bands) in the United States.  The Electronic
Communications Privacy Act of 1989(?) restricted the FCA of 1934
by making it illegal to receive the land-mobile telephone service,
including (I believe) cellular phones.  No restriction was placed
on receiving RADAR (or, curiously, cordless phones.)  Enforcement
of the Virginia law is in violation of the FCA of 1934.  If you have
lots of time and money (and a lawyer, which I'm *not*,) you can
argue this in a federal court and try to have the law overturned.

I can hardly wait to see the responses to this one, but somebody
had to say it...

--
   Lockheed Sanders may disagree so these are solely the opinions of:
             Scott L. Babb - babb@rapnet.sanders.lockheed.com
              "We didn't inherit the Earth from our parents,
                   we are borrowing it from our children."

Newsgroup: sci.electronics
Document_id: 53783
From: jhawk@panix.com (John Hawkinson)
Subject: Building a UV flashlight

Yes, I know it sounds crazy. Call it an urge. Call it what you want.
Just don't ask why :-)

Anyway, I'd like to build a UV flashlight, cheaply. "flashlight" means
it should be reasonably portable, but could have a power pack if
necessary.

My main question is the bulb: where can I get UV bulbs? Do they
need a lot of power? etc., etc.

I'm not too concerned with whether it's long-wave or short-wave
(but hey, if anyone has a cheap source of bulbs, I'll take both).

One other thing: a friend of mine mentioned something about near-UV
light being cheaper to get at than actual UV light. Does anyone
know what he was referring to?

Thanks much.


--
John Hawkinson
jhawk@panix.com

Newsgroup: sci.electronics
Document_id: 53784
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: Circuit Cellar Ink address?

Is CCI still published?  If so, does anyone have their address?


Newsgroup: sci.electronics
Document_id: 53785
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
>
>The Federal Communications Act of 1934 made it *legal* for you to
>operate a radio receiver of any kind, on any frequency (including
>X, K, and Ka bands) in the United States.  The Electronic
>Communications Privacy Act of 1989(?) restricted the FCA of 1934
>by making it illegal to receive the land-mobile telephone service,
>including (I believe) cellular phones.

Illegal to receive land-mobile telephone service?  Don't you have to have a
mobile reciever to even have land-mobile telephone service?  What about
ship-to-shore telephone service?

>No restriction was placed
>on receiving RADAR (or, curiously, cordless phones.)  Enforcement
>of the Virginia law is in violation of the FCA of 1934.

Isin't there some kind of rule (regulation, law, whatever) in some
juristictions that prohibit the use of *police band* recievers
in vehicles?  And that radar transmissions are included in the police band 
so they get covered by the same regulation?

Newsgroup: sci.electronics
Document_id: 53786
From: Kirk_Cowen@panam.wimsey.bc.ca (Kirk Cowen)
Subject: references...

I've got the same problem; I can't dig up any info on the jumper settings
on the hd 3.5" drives.

Can anyone recommend a reference book(s) on the subject, rather than a
"quick fix" type answer??  I was going to start hooking up things and
logging the results, but the prospect of a ten second smoke test deters
me...

Thanks, Kirk Cowen.

-- Via DLG Pro v0.995


Newsgroup: sci.electronics
Document_id: 53787
From: alung@megatest.com (Aaron Lung)
Subject: Re: Motorola XC68882RC33 and RC50

In article <C5qwv2.Bz0@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <sgberg.23xu@charon.bloomington.in.us> sgberg@charon.bloomington.in.us (Stefan Berg) writes:
>>... I don't know why my FPU has an XC (my original 33MHz FPU
>>was label MC68882-33), but it seems to work fine on my system...
>>P.S. Or does it mean eXperimental Chip instead of Motorola Chip? .-)
>
>The rule for the designations is that if it says MC, that means it works
>*exactly* the way the datasheet/book specifies.  If it says XC, that means
>there is at least one known bug.  Often these bugs are small and obscure;
>you might never run into them in practice.
>

XC units are often pre-production sample devices.  Those are normally
distributed for evaluation as freebies and are not guaranteed to
meet every spec.

>At least Motorola admits it, unlike certain other companies...

Yep, that's for sure...that's one thing I like most about Motorola.

aaron

Newsgroup: sci.electronics
Document_id: 53788
From: mont@netcom.com (Mont Pierce)
Subject: Re: 8051 Microcontroller

In article <1993Apr19.194525.3888@lambda.msfc.nasa.gov> bday@lambda.msfc.nasa.gov (Brian Day) writes:
>mcole@spock (COLE) writes:
>
>>I would like to experiment with the INTEL 8051 family.  Does anyone out  
>>there know of any good FTP sites that might have compiliers, assemblers,  
>>etc.?
>
>Try lyman.pppl.gov -- /pub/8051

Great.  This site is a complete shadow of the Signetics BBS 8051 directory.

Thanks Brian,
-- 
Mont Pierce

+-------------------------------------------------------------------------+
| Ham Call: KM6WT             Internet:  mont@netcom.com                  |
|    bands: 80/40/20/15/10/2  IBM vnet:  mont@vnet.ibm.com                |
|    modes: cw,ssb,fm                                                     |
+-------------------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53789
From: jmc@engr.engr.uark.edu (J. M. Carmack)
Subject: RE: Exploding TV

Just a thought........Maybe it possibly has to do with the fact that it
IS an Emerson.  I've got an Emerson VCR which is #6 in the series.  Returned
it six times for various and never the same problems.  Got tired of taking it 
back and fixed it myself.  The Hi-Fi "window" was a bit off.  Something like
the Hi-Fi audio fine-tuning.  When I was a Wal-Mart "associate" in '88-'89,
we had AT LEAST one returned as defective EVERY SINGLE DAY.  How's that for
reliability?  Face it--Emerson can make audio stuff (albeit not of premium
quality), but they CAN'T make anything as complex as video equipment with 
reliability IMHO.  Please, no flames.  Just *had* to share my Emerson disaster
in the light of this exploding tv.  
JC



-- 
-----------------+---------------+-------------+--------------+---------------
La Vie -- C'est Une Plage!  |  ?Caffine Not Present Error | jmc@engr.uark.edu
This Message Printed on     |  Abort, Retry, Fail ?       |
100% recycled electricity.  |                             |  Tangerine!!



Newsgroup: sci.electronics
Document_id: 53790
From: Sean_Oliver@mindlink.bc.ca (Sean Oliver)
Subject: Re: Need to find out number to a phone line

> Joseph Mich Krzeszewsk writes:
>
> Msg-ID: <1quomg$f6m@bigboote.WPI.EDU>
> Posted: 19 Apr 1993 17:49:04 GMT
>
> Org.  : Worcester Polytechnic Institute
>
> Well, this is my second try at posting on this subject. Here goes...
>         In Texas (Corpus Christi at least) if you pick up the phone and
> dial
>         890 the phone company will read the number of the phone you are on
>         back to you. I believe the service department uses this to make
>         certain they are repairing the correct lines when they open the BIG
>         junction boxes. I don't know if it will work but you can give it a
>         try. Good luck.
>
>

Where I live, I use BCTEL. The number to dial is 211 for the same result.

--
+--------------------------------------------+
| Sean Oliver                                |
| Internet Address: a8647@MINDLINK.BC.CA     |
|                                            |
| Mindlink! BBS (604)576-1412                |
+--------------------------------------------+


Newsgroup: sci.electronics
Document_id: 53791
From: mtrek@netcom.com (Chuck L. Peterson)
Subject: 40MHZ Oscilloscope FOR SALE

I'm giving up hardware design and
am selling my Oscilloscope:

	BK Precision  Model 1541B
	40 MHZ Dual-Trace
	Barely Used
	$450 firm   (Fry's sells it for $589+tax)

Prefer people in Silicon Valley, so I don't have to ship it.

mtrek@netcom.com

Newsgroup: sci.electronics
Document_id: 53792
From: jdz1@Ra.MsState.Edu (John D. Zitterkopf)
Subject: Info: NEC70001AB Amp. IC & ~20W AMP secs & possible PSPICE models

Hi,

	Being a Electronic Engineering Student with only Electronic II under
my belt, I find myself *needing* to build a moderate wattage Audio Amp. So, 
I'll throw out a couple of question for the vast knowledge of the 'net'!

	Please Explain how Watts are calculated in Audio Amp circuits. No,
Not P=I*E, Just how it relates to one of the following:

	Ai [Current Gain]
	Av [Voltage Gain]
	Ap [Power Gain]
	or whatever.

I already have a ?wonderful? cheap I.E <$20 schematic for a 20W amp, but
I would like to Cross/improve the circuit. The problem is that the parts
list has IC1 and IC2 as NEC70001AB amplifiers. They look like ?11 pin? 
SIP packages with a heatsink. This schematic was published in a 1991 mag
so it may be non-existant now. Anyway, I tried looking up a replacement in
the latest Digi-key Cat and found it  not listed 8(. The closes I could
figure was a 9 pin SIP as TDA1520BU. Anyone got any Ideas? 

	I thought, hey I can rin a PSPICE simulation using 741 opamp 
models. Yea, great! It worked. But, I guess the 741 wasn't made for High
power amps. As a result, I got a Voltage gain of ~15mV/V. Worse than
I started with 8(... Does anyone have a PSPICE CKT file with cheap yet
good gain? How about some models for some of the chips listed in this 
E-mail? Any ASCII Chip info you guys can send me? 

I'm open to Suggestions/Ideas/Comments/Help!
Please E-mail since I have little time to search the News... 
And I'll post if there's and interest!
John


--
 ____________   _------_  |||IBM & |      EE majors Do it Best 8-)
  --------\\ ] ~-______-~ |||Atari |~~~~~~~~~John D. Zitterkopf~~~~~~~~~~~~~
     (~~~~~\\|_(__ ~~    / | \Rules!jdz1@ra.MsState.edu  jdz1@MsState.bitnet
      \______| (        /  |  \    |AOL: zitt@aol.com  jdz1@isis.MsState.edu 

Newsgroup: sci.electronics
Document_id: 53793
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr20.022922.11861@julian.uwo.ca> wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
>>No restriction was placed
>>on receiving RADAR (or, curiously, cordless phones.)  Enforcement
>>of the Virginia law is in violation of the FCA of 1934.
>
>Isin't there some kind of rule (regulation, law, whatever) in some
>juristictions that prohibit the use of *police band* recievers
>in vehicles?  And that radar transmissions are included in the police band 
>so they get covered by the same regulation?

Those rules/regulations/laws would be subject to the same attack:  that
they are attempting to preempt federal authority to regulate (or not)
radio communications.  Of course, as the original poster noted, court
challenges of this kind can get expensive.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53794
From: randall@informix.com (Randall Rhea)
Subject: Re: Power, signal surges in home...

gstovall@crchh67.NoSubdomain.NoDomain (Greg Stovall) writes:
>Anyway, over the weekend, I was resting on the sofa (in between chores),
>and noticed that I briefly picked up what sounded like ham radio traffic
>over my stereo and television, even though both were off.  Also, all the
>touch sensitive lights in my house start going wacko, cycling through 
>their four brightness states.

>I presume that some ham operator with an illegal amplifier drove past
>my house (I live on a busy thoroughfare); would this be a correct presumption?
>What kind of power must he be putting out to cause the effects?  
>The affected equipment is about 100 feet from the road...

Hams can legally run up to 1500 watts.  It is very unlikely, however,
that a ham would be running that kind of power from a car.  Ham rigs
for cars put out around 100 watts.  It is possible that a 100 watt
radio would cause interference to consumer electronic 100 feet 
away.  Most TVs, stereos, and VCRs have very poor RF shielding.
If you experience the problem frequently, it may be 
caused by a ham, CBer, or other radio operator in a base station
nearby.    The interference may have been caused by a radio 
transmitter used for other purposes, such as police, fire,
etc.  If you heard voices over your stereo, I think you are
correct in assuming that the source is an RF transmitter.

If you have frequent trouble, you may want to try the RF ferrite
chokes available at Radio Shack.  The interference is probably
being picked up by your speaker wires, and those chokes can
be installed on the wires very easily (without cutting them).
Good instructions are included with the chokes.
If that does not solve the problem, you may want to search your
neighborhood for a radio operator.  Look for antennas on the roof
or car.  Talk to him/her about your problem.  There are things
a radio operator can do to reduce interference.

-- 

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Randall Rhea                                        Informix Software, Inc. 
Project Manager, MIS Sales/Marketing Systems    uunet!pyramid!infmx!randall

Newsgroup: sci.electronics
Document_id: 53795
From: mg@cs.princeton.edu (Michael Golan)
Subject: how can 0.022 uF be different from two 0.047 in series?!

I was looking at the amps diagram for Sony 1090/2090 receivers, and I
was amazed to find a difference between the US and Canadian model
on the capacitor(s) that hangs off the output to the speakers:

                         ------\/\/\----- to speaker (identical both models
from amp ---------------|
(idnetical both models) >
                        <  10 
                        >
                        |
                       -----                        
                      |     |                        
        0.022        ---   ---        Canadian model only!
     US model        ---   --- 0.047 
     and world-wide   |     |
     model only.      |    ---        Candian model only!
                      |    ---  0.047
                      |     |
                       ----------- gound

The board itself is also identical, with room for all three caps. The
US/Can versions is clearly indicated in both places.

How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
(there are just standard caps, no special W/type/precision). 

Please explain this
 Michael Golan
 mg@cs.princeton.edu

Newsgroup: sci.electronics
Document_id: 53796
From: buhrow@moria.nfbcal.org (Brian Buhrow)
Subject: NEED HELP FINDING DIP SWITCH SETTINGS AND JUMPER SETTINGS FOR 386SX MOTHERBOARD


Hello net.  I have a 386sx motherboard with the Phoenix BIOS, an on-board
IDE controller port, and two on-board serial ports.  Unfortunately, I don't
have a manual for this beast and I would like to be able to disable the IDE
controller in order to use the MFM controller I have.
The board says it is made in Korea and it uses the Chips Chipset.  If
anyone can give me a clue as to how to go about configuring the board so as
not to use the IDE controller, or how to go about finding out how to do it,
their help would be greatly appreciated.  
	Thank you in advance for your assistance.
Please mail buhrow@nfbcal.org with your responses as my news feed is rather
tenuous.
Thank you very much!
-Brian <buhrow@nfbcal.org>

Newsgroup: sci.electronics
Document_id: 53797
From: randy@ve6bc.ampr.ab.ca (Randy J. Pointkoski)
Subject: Needed 24 volt 4 circuit Flasher


I am looking for a source for a 4 circuit Sequence flasher.

Input 24 Volts AC, 8 amps

Output: sequence to 4 channels (knob to vary frequency) (max 2 amps 
	per leg)
	Switch to put all channels on full time

Please Email any assistance you can provide.

Randy 			Email:  randy@ve6bc.ampr.ab.ca
-- 
   __
  /  )                                               Randy J Pointkoski P.Eng
 /    __________  _   __  _  _   _   o ________      Compression Technologies 
(__/ (_) / / / <_/_)_/ (_</_/_)_/_)_<_(_) / / <_     7141 77 ave

Newsgroup: sci.electronics
Document_id: 53798
From: mgregory@flash.pax.tpa.com.au (Martin John Gregory)
Subject: HELP: MC146818A Real Time Clock Standby Mode


I am having trouble obtaining the specified standby current drain from
a MC146818A Real Time Clock.  Has anyone out there had some experience
in doing this?  The specs call for a few sequences to be met before
standby mode is activated, and are a bit hard to decipher on that, but
I thought that I had it worked out.  However, with a 32kHz crystal the
lowest current drain I can acheive at 3.7V Vcc is 150uA.  This is
three times the specified MAXIMUM under the conditions I am attempting
to create.

I have done the following things:

1) Made sure that RESET/ is asserted for Trlh after powerup, and AS is
   low during this time.


2) Made sure that there is a cycle on AS after the negation of RD/ or
   WR/ during which STBY/ was asserted.

What am I doing wrong?

Thanks very much,

Martin.

Newsgroup: sci.electronics
Document_id: 53799
From: u934132@student.canberra.edu.au (Ogawa / Taro Stephen (ISE))
Subject: Help wanted

Could someone please tell me if a 1/4 decoder is the same as a 1 to 4
demultiplexer. I know how to link 2 of these to get an 8 output circuit,
but how do I link 5 of these to make a 1/16 multiplexer. Sorry if this
seems like a lame question, but I'm only a newbie to electronics, and I
have to do this circuit. Please make any mail as droolproof as possible.

				 Thanx,
					Taro Ogawa
					(u934132@student.canberra.edu.au)

Newsgroup: sci.electronics
Document_id: 53800
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Dmm Advice Needed


|>   What the world needs is a meter that won't let you change ranges or
|> turn it on/off with a lead stuck in the amps jack - a little bit of
|> clever plastic detailing would take care of this and make the world
|> safer for electricans, anyway.
|>    Not that I've ever put a meter on the wrong range into a live 
|> circuit, no, not me...not more than a dozen times, anyway....
|>     Bill
|> 
|> 
|> bills@inqmind.bison.mb.ca
|> The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

The Fluke 87 beeps at you if you try to take it out of a current measuring
range while there is still a lead plugged in to the current sense socket.

... this should solve your problem - unless you are in a noisy environment.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53801
From: corwin@igc.apc.org (Corwin Nichols)
Subject: Re: Fujitsu 8" HDD


The Fujitsu 2322 uses what is known as an 'SMD' interface (Storage Module
Device?).  A lot of older minis used it.  Sun still does on their server
models.  There are several different speeds of SMD, and I think that the 
Fuji drive you have is rated at about 24 Mb/sec (thats megabits).  There
used to be several companies that made couplers for the PC (Interphase in
Texas being one), but I think that the market pretty much has dried up.
Controllers for this type of drive are readily available for VME buses
though.  Rumor has it that there is a SMD to SCSI adapter available, but
I think that it was designed for slower SMD devices.  In other words,
if you have a PC or Mac, that drive is pretty much dogmeat.
Cheers,
Corwin

Newsgroup: sci.electronics
Document_id: 53802
From: ba1634807@ntuvax.ntu.ac.sg
Subject: pwm control thru software


currently I am using the 8051 microcontroller with external eprom..

In order to drive the dc motor (with direction) I use the Pulse width modultion 

thru software control(Assembly language programming). However I am afraid that

they will be overheads and thus alter the pulse timing. My question is 

is the software pwm control reliable?. I understand that port 0 is a latch

and so I vary the duty cycle by setting it high first and at the desire 

duty cycle then I set low..? Any improments ?
 

 

Newsgroup: sci.electronics
Document_id: 53803
Subject: Re: Looking for Electronics Dept Info in Austrailia
From: MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham)

In <1993Apr19.003800.18288@worak.kaist.ac.kr> hjkim@hyowon.pusan.ac.kr writes:

> Hi Netters!
> 
> I am looking for the list of universities in Austrailia, which has electronics department. 
> I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
> But I don't have any information about Austrailian Universities.
> Can anybody recommend a good university in communication area?
> Any comments will be welcomed!
> 
> Bye.
> 
> Jaehyung Kim
> 
Well, I honestly don't know if they are good, bad or indifferent, but there
is an electronics dept here at La Trobe:
La Trobe University, Bundoora VIC 3083 Australia
Fax +613 471 0524
Chairman is Prof Ian White. Sorry, don't have an email address.
Graham B

Newsgroup: sci.electronics
Document_id: 53804
From: NWZ96H@cheltenham-he.ac.uk (NWZ96H)
Subject: Hatley & Pirbhai help...

Hello,

Has anyone used the Requirements Analsys methodology Hatley & Pirbhai ? I am
a British final year real-time degree student, and as a project I am covering
this methodology. I would be very grateful to anyone who could give me their
views on this method. Please mail me if you feel you can help, and I will send
you my questions.

Thanks in advance,

David Phelps	(nwz96h@chelt.ac.uk)


Newsgroup: sci.electronics
Document_id: 53805
From: dp@cec1.wustl.edu (David Prutchi)
Subject: OEM weight scale

Does someone sell OEM scale units with either analog or digital output?
I need something like the scales used in supermarket cash registers, 
with a dynamic range of a few pounds and reasonable accuracy.

Any sources ?        -David

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive           <prutchi@eng.tau.ac.il>     |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53806
From: d2bohre@dtek.chalmers.se (Henrik Bohre)
Subject: Digital Answering mach

Does anybody know anything about the chips D6275A/D6235A/D6205A chips from
DSP Telecommunications Inc?

I'd greatly appreciate information about price, pinouts and peripherals.

Regards,

  Henrik Bohre

  @>-+--

Newsgroup: sci.electronics
Document_id: 53807
From: mvanhorn@desire.wright.edu (H.I.T. ( Hacker-In-Training ))
Subject: Re: Need to find out number to a phone

Since I have seen various different numbers to dial to get your number read
back to you by the phone company, could someonepost a list or point me to a
book where I could get a list of all the different numbers for the U.S.?
Failing that, could someone tell me Ohio's?


-- 
???????????????????????????????????????????????????????????????????????????????
?	451                             ?	I don't speak for Wright      ?
?  	mvanhorn@desire.wright.edu	?       State, I just give them       ?
?	Wright State University         ?       huge amounts of money.        ?
???????????????????????????????????????????????????????????????????????????????

Newsgroup: sci.electronics
Document_id: 53808
From: keith@churchill.ColumbiaSC.NCR.COM (Keith.Boyd)
Subject: Re: Need to find out number to a phone line

In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:
>
>Greetings!
>      
>        Situation:  I have a phone jack mounted on a wall.  I don't
>                    know the number of the line.  And I don't want
>                    to call up the operator to place a trace on it.
>
>        Question:   Is there a certain device out there that I can
>                    use to find out the number to the line?
>        Thanks for any response.
>                                                    Al
>
>  

Do you get a dial tone when you plug a phone into the jack??  If not,
then the line is possibly disconnected from the nearest telco junction
box. If you do get a dial tone, then surely the telco is sending a bill
for the line to *someplace* or *somebody*. Are you sure that what you
are doing is on the level. Sounds to me like you are just trying to get 
at somebody's unlisted number.  Fess up.

Keith


-- 
| Keith Boyd  (NCR- MCPD Cola.) |  Nothing could be finer than huntin' and   |
| 3325 Platt Springs Rd.        |    and fishin' in South Carolina! -Me-     | 
| West Cola., S.C. 29170 |   Go Gamecocks!   | keith.boyd@columbiasc.NCR.COM |
| Vp: 803-791-6419 or 6455    | From uunet: uunet!ncrcom!ncrcae!clodii!keith | 

Newsgroup: sci.electronics
Document_id: 53809
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)

In article <1qg98sINNokf@sheoak.ucnv.edu.au> j. pethybridge,
jeff@redgum.ucnv.edu.au writes:
> I asked this a year ago, but i am still looking.
> I am getting sick of having to use a HC373 or a 8751/2.
Check out Xicor's new goodie in the April 12th edition of EETimes
X88C64 - an 8k * 8 E2PROM with built in latch AND bootloader setup.
You hook it directly to your '51, power it up, the prom initialises the
serial port on the '51, you load in your code via RXD, this gets blatted
onto the E2PROM, then you reset and run - i'm sure Dallas also does
something like this too, i suppose it would boil down to relative
prices, and the Dallas part freeing up P0 & P2 completely. I wonder
if ANYONE has ever managed to design a single sided PCB with an
8051, 573, EPROM, SRAM and >>NO LINKS<< ?
cheers
Mike.

Newsgroup: sci.electronics
Document_id: 53810
From: fontana@cis.ohio-state.edu (Mark Fontana)
Subject: Homemade projector automation


Hi all,

I'm an assistant manager at a local art theater here in Columbus.  I'd
like to expand our show automation a bit- namely add the capability to
use cue tapes to bring the houselights up.  Our current automation
consoles date from the early 60's and don't provide this function.

We already have the combo failsafe/contact rollers to read the cuetapes,
and our dimmer system will raise the houselights when its fade-up control
circuit (120 VAC) is momentarily closed, for at least 0.5 second.

I've tried wiring the dimmer control to a 12V relay, activated when the
cue tape completes the circuit.  Low tech and simple, but there's one
problem:  In order to get the 1/2 second pulse, there needs to be
a sh**load of cuetape on the film.  (35mm runs at 90 feet per minute,
so to get a 1/2 second pulse, there needs to be at least 9 inches of solid
cuetape!)

Ideally, I would like to use a single cross-cue to accomplish this function.
(A single strip of cuetape perpendicular to the length of the film)
This would give a pulse of approximately 1/100 of a second.
What I need is a circuit to detect the short cue and activate the relay
for around 1/2 second.  The ability to adjust how long the relay
is activated would be nice.  I figure this would require an RC circuit
of some sort.  I'm sure some of you already have the solution figured
out in your heads.  Any suggestions and schematics would be appreciated!


Thanks,

Mark Fontana

-- 
 "Of all the arts, the cinema is  |  Mark A. Fontana
  the most important."            |  Computer and Information Science
                    --V.I. Lenin  |  THE Ohio State University

Newsgroup: sci.electronics
Document_id: 53811
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Cicuit Cellar Ink - Extras 4 Trade

In article <babb-190493113153@larc.sdsu.edu> babb@sciences.sdsu.edu (J. Babb) writes:
>Fellow Info-junkies,
>  I have an extra CCI #27 (Real Time Programming/Embedded Sensors &
>Storage) and an extra CCI #32 (Voice control of telescope, among other
>articles). No labels. No torn, cut-up, or missing pages.
>
>Would like to trade for CCI # 26, or CCI # 23, or CCI # 19 in same
>condition (Labels OK).
>
>I mail mine you mail yours mutual trust kinda thang OK?
>You don't actually throw them away, do you?
>
>Thanx,
>Jeff Babb
>babb@sciences.sdsu.edu

I have also been trying to complete my collection.  I have an extra CCI # 16
(Communications) and a # 12 (Applications in the Arts), both in mint
condition.

I would like to trade for (or buy) the following: # 1, 3, 22, 23, 25, 26, 30,
and 31.

Thanks      -David

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53812
From: kng@pt.com (Ken Gravenstede)
Subject: Decent, CHEAP 20+MHZ Scopes?

Any info on modern 20MHZ or better dual trace scopes would be appreciated.
Should I buy a used one or a new one?  And where?

Please E-Mail.

Thanks in advance.

Ken
-- 
__
Ken Gravenstede, Performance Technologies Incorporated	kng@pt.com
315 Science Parkway, Rochester, New York 14620            uupsi!ptsys1!kng

Newsgroup: sci.electronics
Document_id: 53813
From: cab@col.hp.com (Chris Best)
Subject: Re: Food Dehydrators

>   Does anybody out there have one of those food dehydrators I've been seeing
> all over late-night TV recently? I was wondering if they use forced air, heat,
> or both. If there's heat involved, anybody know what temperature they run at?
> My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
> and a heater. Seems to me you should be able to throw a dehydrator together
> for just a few bucks. Heck, the technology is only what? 1,000 years old?

----------

Yeah, but 1000 years ago, you couldn't buy it from a guy with sprayed-on hair!

Newsgroup: sci.electronics
Document_id: 53814
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In <1993Apr19.185326.9830@Princeton.EDU> mg@cs.princeton.edu (Michael Golan) writes:

>I was looking at the amps diagram for Sony 1090/2090 receivers, and I
>was amazed to find a difference between the US and Canadian model
>on the capacitor(s) that hangs off the output to the speakers:

>                         ------\/\/\----- to speaker (identical both models
>from amp ---------------|
>(idnetical both models) >
>                        <  10 
>                        >
>                        |
>                       -----                        
>                      |     |                        
>        0.022        ---   ---        Canadian model only!
>     US model        ---   --- 0.047 
>     and world-wide   |     |
>     model only.      |    ---        Candian model only!
>                      |    ---  0.047
>                      |     |
>                       ----------- gound

>The board itself is also identical, with room for all three caps. The
>US/Can versions is clearly indicated in both places.

>How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
>(there are just standard caps, no special W/type/precision). 

>Please explain this
> Michael Golan
> mg@cs.princeton.edu

The only explanation I can think of is that two capacitors in series
can handle twice the output voltage. Sometimes two elco's in antiseries
(you know, positive sides facing eachother) are used to obtain a large
capacitor that can handle positive and negative voltages as well.

So there probably is no design-philosophical reason, but a production-cost
one.

Best 73's

Wouter

Newsgroup: sci.electronics
Document_id: 53815
Subject: 68HC16 public domain software?
From: murashiea@mail.beckman.com (Ed Murashie)

Does anyone know of an FTP site where I might find public
domain software for the Motorola 68HC16 microprocessor?
I am looking for a basic interpreter/compilier or a 'C'
compiler.  Thanks in advance.
					Ed Murashie

------------------
Ed Murashie                     US Mail :  Beckman Instruments Inc.
phone: (714) 993-8895                      Diagnostic System Group 
fax:   (714) 961-3759                      200 S. Kraemer Blvd  W-361
Internet: murashiea@mail.beckman.com       Brea, Ca 92621  

Newsgroup: sci.electronics
Document_id: 53816
From: aj008@cleveland.Freenet.Edu (Aaron M. Barnes)
Subject: Realistic PRO-2024 scanner for sale:was $200, sell for $150




Article 10886 of alt.radio.scanner:
Path: usenet.ins.cwru.edu!cleveland.Freenet.Edu!aj008
From: aj008@cleveland.Freenet.Edu (Aaron M. Barnes)
>Newsgroups: alt.radio.scanner
Subject: Realistic PRO-2024 for sale-was $200,sell for $150 obo
Date: 20 Apr 1993 16:01:28 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
Lines: 26
Message-ID: <1r16oo$3du@usenet.INS.CWRU.Edu>
NNTP-Posting-Host: slc10.ins.cwru.edu


Hello.

I have a Realistic PRO-2024 scanner for sale.Here is a small desc
ription:

60 programible chanels
fully detailed backlighted digital display
headphone jack
antenna jack
removable telescoping antenna
auto search

coverage:
30-50mHz
118-174mHz
380-512mHz

It originally cost $200, but I will sell for $150.

Thank You.
-- 
       / /     Buchanan in `96!
      / /      Fear the goverment that fears your guns.
  \ \/ /       Without the 2nd amendment, we cannot guarantee ou
   \/ /        r freedoms.           aj008@cleveland.freenet.edu
-- 
       / /     Buchanan in `96!
      / /      Fear the goverment that fears your guns.
  \ \/ /       Without the 2nd amendment, we cannot guarantee ou
   \/ /        r freedoms.           aj008@cleveland.freenet.edu

Newsgroup: sci.electronics
Document_id: 53817
From: johnr@col.hp.com (John T. Rasper)
Subject: ADCOM GTP500II IR sensor & repeater spec's?

Does anyone know the details of the interface (5 wire din) for the
IR remote sensor & (2 wire IR repeater) for the ADCOM GTP-500II
preamp?  The ADCOM part numbers are the XR-500II, SPM-500II, and 
IRA-500II.

A cursory physical examination of the pre-amp connector indicates
that the connector (5 pin din) may provide: (Viewed from connector front)

      |
   5     1     (pin ?) +?v @ ???mA
    4   2      (pin ?) +/-?v @ ???mA
      3        (pin 3) Signal Ground
               (pin ?) Demodulated signal ?V-pp, ? polarity, ? mA drive
               (pin ?) Signal to drive repeater LED (drives through 150ohm
                       resistor) ?V-pp

I assume that the repeater connectors (mini-plugs) drive the IR repeater
LED's directly.  True?

Can anyone fill in the ?'s.  Thanks.

--
John Rasper                         Hewlett-Packard COL
johnr@col.hp.com                    P.O. Box 2197
(719) 590-5895                      Colorado Springs, CO 80901-2197

Newsgroup: sci.electronics
Document_id: 53818
From: moffatt@bnr.ca (John Thomson)
Subject: Re: What is Zero dB????

marrevola@rediris.es wrote:
: In article <1993Apr6.132429.16154@bnr.ca>, moffatt@bnr.ca (John Thomson) writes:
: > Joseph Chiu (josephc@cco.caltech.edu) wrote:
: > 
: > : And the measure of current, Amp, is actually named after both the AMP company
: > : and the Amphenol company.  Both companies revolutionized electronics by
: > : simulatenously realizing that the performance of connectors and sockets 
: > : were affected by the amount of current running through the wires.
: > 
: > Sorry.  The unit for current is the AMPERE which is the name of a french-man
: > named AMPERE who studied electrical current.  The term AMP is just an abbreviation
: > of it.  The company AMP came after the AMPERE unit was already in use.
: >   
: > : The Ohmite company was the first to characterize resistances by numbers, thus
: > : our use of the Ohms...
: > 
: > I don't know about this one, but it doesn't sound right.
: Are you (two) joking?
: Is the entire Internet flaming you (two)?
: Ahh!, now I remember that Ohmite company was the first introducing "the pink
: colored resistor", only for electronics working females ;-)
: -- 
: Manuel Arrevola Velasco   ||||| True e-mail: manolo@taf.fundesco.es |||||
: DoD #1033
: 
Yes, I have taken a bit of flame on this one.  I must've been half asleep when
I posted a response to Joseph.

Greggo.
-----
Greg Moffatt  moffatt@bnr.ca
Bell-Northern Research Inc., Ottawa Canada
"My opinions; not BNR's"

Newsgroup: sci.electronics
Document_id: 53819
From: philip@mentorg.com (Philip Peake)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr20.022922.11861@julian.uwo.ca>, wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
|> In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
|> 
|> >No restriction was placed
|> >on receiving RADAR (or, curiously, cordless phones.)  Enforcement
|> >of the Virginia law is in violation of the FCA of 1934.
|> 
|> Isin't there some kind of rule (regulation, law, whatever) in some
|> juristictions that prohibit the use of *police band* recievers
|> in vehicles?  And that radar transmissions are included in the police band 
|> so they get covered by the same regulation?

What do you mean by "police band" - there is no such thing.

Anyway, radar detectors work in shared bands.
If you applied your test, all of those radar operated door
openers in malls would be illegal.

One of the great problems here is that there are too many
ill-educated (read illiterate) people making too many laws
about subjects on which they are incompetent - there may well
be laws refereing to "police bands", they are almost certainly
local in scope (state or county) - created by well-meaning,
but incompetent idiots.

Unfortunaltely, laws do not have to be sensible (or even enforceable).
Lawmakers exist to pass laws - and will continue to do so, until
the day where you are faced with death for not doing X, and
amputation of all your limbs for doing X ... the choice will be yours.

Note: no smiley.

Philip

Newsgroup: sci.electronics
Document_id: 53820
From: dclaar@cup.hp.com (Doug Claar)
Subject: Los Angeles Freeway traffic reports

While driving through the middle of nowhere, I picked up KNBR, AM 1070,
a clear-channel station based in Los Angeles. They had an ad 
claiming that they were able to get traffic flow information from 
all of the thousands of traffic sensors that CalTrans has placed
under the pavement. Does CalTrans sell this info? Does KNBR have
an exclusive? What's the deal?

==Doug "Former L.A. commuter" Claar

Newsgroup: sci.electronics
Document_id: 53821
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Suggestions  on Audio relays ???

In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>I built a little project using the radio shack 5vdc relays to switch
>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>most of the common things one is supposed to do when using relays and
>>nothing seemed to get rid of the clicks.
>>
>>
>>My question is:
>>
>>	Is there a good relay/relay circuit that I can use for switching
>>audio, so that there will be *NO* noise of any kind on the audio lines.
>>
>>
>>I will appreciate any advice or references to advice.  Also, exact part
>>numbers/company names etc. for the relays will help!
> 
> Are you switching high level signals or low level signals like pre-amp
> out level signals?  Also, are the clicks you mentioning the big
> clack that happens when it switches or are you refering to contact
> bounce?  How are you driving the relays?  TTL gate output?  Switching
> transistor?  How are the relays connected to what you are driving?
> 
> Need more specifics to answer your question!! :-)

As a general rule, no relay will cleanly switch audio if you try to tranfer
the circuit with the contacts.  The noise you hear is due to the momentary
opening and closing of the path.

The noiseless way of transfering audio is to ground the circuit.  In high
impedance audio circuits a resistive "T" is constructed close to characteristic
impedance of the circuit.  Grounding the imputs (connected to the T) transfers
the audio.

In low impedance circuits transformers are usually used, and the inputs are
shorted out or grounded.  Secondaries are paralleled at the characteristic
impedance.

Sometimes if it is necessary to actually switch audio, a second contact is used
to momentarily short the circuit output for the duration of the switching time.

Telephone relays are handy, because contacts can be adjusted to "Make before
break and Vica Versa" but I haven't seen any of these for years.

Nowadys switching is done electronically with OP amps, etc.

A novel circuit I used to build was a primitive "optical isolator".. It consists
of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
off the cell is high resistance.  Turn the lamp on and the resistance lowers
passing the audio.  Once again this device in a "T" switches the audio.  Varying
the lamp resistance give a remote volume control.  Use 2 variable resisters and
you have a mixer!

Lots of luck!
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
Document_id: 53822
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: correction of last followup re relays

In article <1993Apr20.102756.1709@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
> In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
>> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>>I built a little project using the radio shack 5vdc relays to switch
>>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>>most of the common things one is supposed to do when using relays and
>>>nothing seemed to get rid of the clicks.
>>>
>>>
>>>My question is:
>>>
>>>	Is there a good relay/relay circuit that I can use for switching
>>>audio, so that there will be *NO* noise of any kind on the audio lines.
>>>
>>>
>>>I will appreciate any advice or references to advice.  Also, exact part
>>>numbers/company names etc. for the relays will help!
>> 
>> Are you switching high level signals or low level signals like pre-amp
>> out level signals?  Also, are the clicks you mentioning the big
>> clack that happens when it switches or are you refering to contact
>> bounce?  How are you driving the relays?  TTL gate output?  Switching
>> transistor?  How are the relays connected to what you are driving?
>> 
>> Need more specifics to answer your question!! :-)
> 
> As a general rule, no relay will cleanly switch audio if you try to tranfer
> the circuit with the contacts.  The noise you hear is due to the momentary
> opening and closing of the path.
> 
> The noiseless way of transfering audio is to ground the circuit.  In high
> impedance audio circuits a resistive "T" is constructed close to characteristic
> impedance of the circuit.  Grounding the imputs (connected to the T) transfers
> the audio.
> 
> In low impedance circuits transformers are usually used, and the inputs are
> shorted out or grounded.  Secondaries are paralleled at the characteristic
> impedance.
> 
> Sometimes if it is necessary to actually switch audio, a second contact is used
> to momentarily short the circuit output for the duration of the switching time.
> 
> Telephone relays are handy, because contacts can be adjusted to "Make before
> break and Vica Versa" but I haven't seen any of these for years.
> 
> Nowadys switching is done electronically with OP amps, etc.
> 
> A novel circuit I used to build was a primitive "optical isolator".. It consists
> of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
> off the cell is high resistance.  Turn the lamp on and the resistance lowers
> passing the audio.  Once again this device in a "T" switches the audio.  Varying
> the lamp resistance give a remote volume control.  Use 2 variable resisters and
> you have a mixer!
> 
> Lots of luck!
> -- 
> 73, Tom
> ================================================================================
> Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
> (604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
> Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  
> 
> I do not recyle.....   I keep everything!       (All standard disclaimers apply)
> ================================================================================
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
Document_id: 53823
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: correction re Audio relay followup

Gremilins have attacked my keyboard and the correction to my followup on audio
relays got fouled up.  
Varying lamp resistance, should read, "Varying lamp voltage"
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
Document_id: 53824
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Building a UV flashlight

You can get a *little* UV by putting a heavy UV filter (deep purple) in
front of an ordinary flashlight bulb (the brightest you can get).
My father used a setup like this in law enforcement work circa 1964.

Good UV ("blacklight") bulbs work like fluorescent bulbs.  I'd proceed by
getting a cheap battery-powered _fluorescent_ light, then going to an
electrical supply house and finding a UV bulb that would fit it.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53825
From: kehoe@netcom.com (Thomas David Kehoe)
Subject: Re: Telephone Controlled Power Bar Needed


I had a similar idea, for a fax/answering machine switch,
to put both machines on one line.  You order distinctive
ringing from your phone company.  This is $3/month here.
You get a second (unpublished) phone number.  When
someone calls this number, your phone rings with short
rings instead of long rings.

You set up your answering machine on 4 rings and your fax
on six rings.  You'd give out the new # as your fax #.
A device would measure the length of rings.  When it
detects a short ring, it turns off your answering machine.
Five rings later your fax picks up the call.

This should be cheaper and more elegant than the $80
switches now available.

But that's not what I did.  I'm giving out the new
# to my friends and customers.  This should leave the
old # for telemarketers, etc.  I won't pick up the
phone when I hear the long rings.
-- 
"Why my thoughts are my own, when they are in, but when they are out
they are another's." - Susannah Martin, hanged for witchcraft, 1692.
Thomas David Kehoe          kehoe@netcom.com         (408) 354-5926

Newsgroup: sci.electronics
Document_id: 53826
From: <PCA103@psuvm.psu.edu>
Subject: ATARI 2600 Processors

Does anyone know what processor the Atari 2600 used? What I'm looking for is th
e pin-outs for the Atari 2600.... the schematics for it it... does anyone have
any idea where I could find this or any related information? This is very impor
tant. Also, are the ROM chips that were used fo rthe 2600 games still available
, or were they propreitary? Please email me with any responces, as this is very
 important.. Thanks a million...

BTW- Anyone who works/has worked for Atari, I could really use your help with i
nfo on the old 2600, please email me if you are willing to help me.... thatnks
alot!!

-Peter

Newsgroup: sci.electronics
Document_id: 53827
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dmm Advice Needed

I've had my Fluke 8060A here at work for just over 10 years now.
It is a wonderful meter.  Several colleagues here have some of the
newer Fluke meters, though I still would just as soon hang on to my
8060.  The 8060 a is the 1980s digial "analog" to the Simpson 260
analog DMM of the 1950-1960s.  There was/is (?) an 8060B that had
extended frequency response.

I've got a nifty little pen shaped meter made by Soar that I keep
in my toolbox at home.  I've had that for six or seven years now
and only replaced the batteries a couple of timees; it is more than
adequate for day-to-day hobby use.  I think Soar OEMs their stuff
for a number of vendors.  Some of JDR Microdevices' stuff looks
rather similar to Soar's.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53828
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: help: How to reduce the RPMs of a Boxer fan ?

Yes, you increase the RPM slip of a "boxer" type fan by installing
a capacitor in series with the fan's power supply.  The air flow of
small 3.5 inch fans can be reduced by about 50% by using a 1 to 4
uF capacitor.  Use a good grade nonpolarized unit with working
voltage rating around 250 volts.  Note that some impriical study is
usually required to experimentally determine the best size
capacitor for a given application.

For DC powered applications, try the Radio Shack 12 volt box fan.
It can run and start reliably from as low as about 4.5 VDC.  It is
exceptionally quiet, but at admittedly low flow.  I wish I knew who
made the fans for Radio Shack.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53829
From: cantrell@sauron.msfc.nasa.gov (Eric Cantrell)
Subject: EEG Kit?

Awhile back someone posted some information on where you can get
kits to build an EEG.  Does anyone remember where you could get
this.  I'm very interested in getting some info on this.  Thanks 
in advance.

eric

cantrell@sauron.msfc.nasa      


Newsgroup: sci.electronics
Document_id: 53830
From: coyne@thing1.cc.utexas.edu ()
Subject: Re: Radar detector DETECTORS?

It is illegal to use anything you eavedropped on for a business 
or for an illegal use.  Jurisdictions that ban radar detectors or
police monitors, are essentially making the claim that there is no
other reason for a radar detector or police radio monitor. 

The results of fighting these claims in courts have been mixed.
The federal courts are not anxious to intervene and state courts
have sometimes held that the feds have exclusive jurisdiction
and sometimes they have not.  A lot of state courts do not have
enough imagination to see any use for a radar detector besides
avoiding law enforcement action for speeding.

When you buy a radar detector, amongst the guarrantees, instructions, 
explanations, and other detritus, is an invitation to join an
association dedicated to preserving your right to use a radar detector.
(I promise I am not making this up!)

I do not think radar detector manufacturers would be making any 
headway at all in courtrooms if police departments enforced speed 
laws with a strict eye to public safety and a blind eye to the fund
raiser aspect of tickets.  

Mike Coyne


Newsgroup: sci.electronics
Document_id: 53831
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Dayton Hamfest

Yes,

Take Interstate I-70 to the route 48 exit.  Go south on 48 about
2-1/2 miles.  Trun right on Shiloh Springs Road.  The hamvention is
at the Harrah arena, which is about 1 mile west and on the north
side of the Road.  Parking at the arena is limited.  Lodging is
probably entirely booked-up within a 40 mile radius.  Good luck.

                |                |
                48               I75
                |                |
----------I70----------....---------
                |                |
                |                |
          X     |                |
(mall)  --------|                |
   S. Springs   |

It is possible to park at the mall to the west.  There are shuttle
busses running between the arena and the mall.

If possible, get a Montgomery County, OH map from your local AAA
office.  It should be free if you are an AAA member.

If you don't already have definite plans, now is not a particularly
good time to start to think about going to the hamvention.



-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53832
From: verity@jack.sns.com (Steve Verity)
Subject: Need help with video detection circuit



I am trying to build a circuit that detects the presence of video (Vs.
a blank screen) by monitoring the R,G, and B outputs of a graphics
card.  It should be able to detect the presence of a single pixel at
65 MHz, which would mean detecting a 15 NS pulse.  It should also be
able to tell the difference between a blank screen (about 300 mv)
and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
cheap.  

My first circuit was a dismal failure.  I used 3 compariators; each
compariator had the + input going to one of the guns, the - input
went to a reference created by a voltage divider(a potentiometer).

The first problem was that the compariator was way too slow.. I
needed to get several pixels in a row before it would fire the
compariators, so I could have a whole screen full of text, but my
circuit would not detect it.   

The second problem is that there was more noise on the reference then
the smallest difference between a blank screen and a dim screen.  In
fact the difference between completely black and completely white is
only 650 mv.  I am wondering if I am going to have to amplify the
video signals to make this work.  

There are faster compariators, but they are expensive, and require 
split supplies.   I would need to replace my .49 quad compariator
with three 1.89 compariators, and create a whole new power supply
circuit.  

At this point, I think what I need is some sort of transistor
circuit.  Transistors are fast and cheap and should do the trick...

Unfortunately, I am way out of my league when It comes to designing
transistor circuits, so I am appealing to the net for help.  Any
ideas, tips, circuits, pointers, references, etc. would be greatly
appreciated.  

Oh yes, I only sample the output of this thing every second or so, so
I don't need a fast response time at all, however, I haven't found a
way to take advantage of that fact.

Thanks a lot for any help anybody might be able to give. Of course,
you will have my undying gratitude.


Steve Verity




-- 
..........>.........>........>......>...>...>..>..>..>..>.>.>.>>>>>>>>+ .   
Steve Verity                  +   +             ...Maxed on MIDI        + .
                                    +      verity@jack.sns.com      + ..   +

Newsgroup: sci.electronics
Document_id: 53833
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Long distance IR detection


--

I would like to be able to detect the angular position (low accuracy) of an
IR emitting source at a distance of about 100 meters (more is better) in
daylight.  The IR source could be emitting a signature; I'm leaning toward
30 KHz square wave with 50% duty cycle.

I am considering the use of a quadrant detector from Centronic Inc. to give
information to a pan/tilt head to point the sensor and thus determine the
angles.  For the source I am considering wazing the heck out of an IR LED(s),
possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
current pulses.  At this current the duty cycle of the LED drops to 10% and I
would need to cycle five of them in turn to get the 50% required.

Has anyone done something like this?

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
Document_id: 53834
From: drand@spinner.osf.org (Douglas S. Rand)
Subject: Re: Power, signal surges in home...

In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:

   gstovall@crchh67.NoSubdomain.NoDomain (Greg Stovall) writes:
   >Anyway, over the weekend, I was resting on the sofa (in between chores),
   >and noticed that I briefly picked up what sounded like ham radio traffic
   >over my stereo and television, even though both were off.  Also, all the
   >touch sensitive lights in my house start going wacko, cycling through 
   >their four brightness states.

   >I presume that some ham operator with an illegal amplifier drove past
   >my house (I live on a busy thoroughfare); would this be a correct presumption?
   >What kind of power must he be putting out to cause the effects?  
   >The affected equipment is about 100 feet from the road...

Hams are unlikely to have an illegal amp,  and are also unlikely to
have a "dirty" amp.

   Hams can legally run up to 1500 watts.  It is very unlikely, however,
   that a ham would be running that kind of power from a car.  Ham rigs

Not possible either.  You'd need about a 300 amp alternator for
just the amplifier.  I can just see it.  You need to slow
down on a downgrade,  so you hit the push to talk button.

   for cars put out around 100 watts.  It is possible that a 100 watt
   radio would cause interference to consumer electronic 100 feet 
   away.  Most TVs, stereos, and VCRs have very poor RF shielding.
   If you experience the problem frequently, it may be 
   caused by a ham, CBer, or other radio operator in a base station
   nearby.    The interference may have been caused by a radio 
   transmitter used for other purposes, such as police, fire,
   etc.  If you heard voices over your stereo, I think you are
   correct in assuming that the source is an RF transmitter.

   If you have frequent trouble, you may want to try the RF ferrite
   chokes available at Radio Shack.  The interference is probably
   being picked up by your speaker wires, and those chokes can
   be installed on the wires very easily (without cutting them).
   Good instructions are included with the chokes.
   If that does not solve the problem, you may want to search your
   neighborhood for a radio operator.  Look for antennas on the roof
   or car.  Talk to him/her about your problem.  There are things
   a radio operator can do to reduce interference.

And please remember to be friendly when approaching your
local radio operator.  This person may or may not be the 
cause of your troubles,  and you'll get better cooperation
and help if you assume that he is going to be helpful (most
are).  It was amazing the accusations that we sometimes
dealt with as I grew up.  We were blamed for skip (ghost
pictures on the TV that occur at sunspot peaks),  c.b.
interferance,  dead grass :),  you name it.  

BTW, the local operator should try and help you whether or
not he or she is directly responsible.  It is part of
being a good neighbor and that is how the FCC views it.
Too bad they don't require the consumer equipment makers
to take any precautions.

Last, you can usually tell ham radio vs. CB.  Ham operators are
required to declare their call (sign) every so many minutes (no more
than 10).  So if you hear "This is WA1QT" or some other call starting
with A, W or K and no more than 6 total characters, you heard a ham.
CB'ers probably won't sign (I don't know that they're even required
to) and fire/police have other private ids.






--
Douglas S. Rand <drand@osf.org>		OSF/Motif Dev.
Snail:         11 Cambridge Center,  Cambridge,  MA  02142
Disclaimer:    I don't know if OSF agrees with me... let's vote on it.
Amateur Radio: KC1KJ

Newsgroup: sci.electronics
Document_id: 53835
From: hl00@ns1.cc.lehigh.edu (HOU-SHENG LIN)
Subject: Laser vs Bubblejet?

Well, I'm not too sure if this would be the right place to post this, but
anyway, here goes:  I was just noticing that some of the current bubblejet
printers offers up to 360x360 resolution while a lot of lower end laser
printers only offer 300x300.  However, the laser printers still seems to be
significantly pricier than the bubblejets... how is this?  Or am I missing
something about the resolution thing?

-- 
-Sheng
hl00@pl122.eecs.lehigh.edu
hl00@m180k.cc.lehigh.edu
hl00@lehigh.edu

Newsgroup: sci.electronics
Document_id: 53836
From: monta@image.mit.edu (Peter Monta)
Subject: Re: MC SBI mixer

musone@acsu.buffalo.edu (Mark J. Musone) writes:

> P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
> ELECTRICAL DIAGRAMS would help a lot.
> I have seen a lot of theory books with no circuits and a lot of
> circuit books with no theory, but one without the other does not help.

Mixers have a wide variety of implementations; the Mini-Circuits
part you mention is a doubly-balanced diode mixer, but active ones
(BJT, FET) seem more popular in consumer receivers.  You might
call MCL; they have a nice catalog.

The universal answer for wide-coverage, theory+practice, RF design
is the _ARRL Handbook_, published by the American Radio Relay
League, the radio amateur organization.  Any technical bookstore
can order you one.  The book is superb, with lots of accessible
theory, construction projects, and generally interesting stuff.

You might also check out _Solid State Design for the Radio Amateur_
(I think), by Hayward and <someone>.  This has sharper design
and test information about subsystems like mixers.

Peter Monta   monta@image.mit.edu
MIT Advanced Television Research Program

Newsgroup: sci.electronics
Document_id: 53837
From: geva@concave.cs.wits.ac.za (Geva Patz)
Subject: How do I make me own really-short-run CD's

I want to be able to take a bunch of home-made songs (from DAT or other 
suitable master) and output them to a short run (10-20 off) of standard 
music CDs. Would one of the CD recorders designed for writeable CD ROMs work 
for this purpose? Alternatively, is there a service that does this sort of 
thing for a fee? 

I'm after as much information as possible on the alternatives (cost, lead 
time, equipment required, procedure to follow, etc.)  Email replies would be 
appreciated.

%%%%     Geva Patz
 Geva    Department of Computer Science, WITS University
  %%%%   geva@concave.cs.wits.ac.za

Newsgroup: sci.electronics
Document_id: 53838
From: sehari@iastate.edu (Babak Sehari)
Subject: How to the disks copy protected.

---

I was wondering, what copy protection techniques are avaliable, and how
effective are they?  Has anyone have any experience in this area?

                      With highest regards,
                           Babak   Sehari.


-- 

Newsgroup: sci.electronics
Document_id: 53839
From: jung@rz.tu-ilmenau.de (Dirk Junghanns)
Subject: W86C451, W86C456 info wanted

Does anybody have informations about the

 W 86 C 451   and  W 86 C 456 chips (40pin DIL pckg)?

They are build in a multifunction io-card for pc.

Thanks 
         Dirk
-- 
------------------------------------------------------------
Dirk Junghanns                    junghanns@rz.tu-ilmenau.de
------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53840
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Power, signal surges in home...

drand@spinner.osf.org (Douglas S. Rand) writes:

>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>   that a ham would be running that kind of power from a car.
>
>Not possible either.  You'd need about a 300 amp alternator for
>just the amplifier.

It is too possible.  As the original poster said "it is very unlikely"
but definately possible.  (Can you say batteries?)

Newsgroup: sci.electronics
Document_id: 53841
From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
Subject: PADS Question - How do I go from a schematic -> PCB?

After I have produced a schematic with PADS-LOGIC, how do I import it into 
PADS-PCB to create a PCB pattern?  The only way I've gotten it to work is
to output a FutureNet netlist, and then import this into PADS-PCB.  Is there
another way of doing this?  I didn't see any information in the instructions
provided, but I might have missed something.  Any suggestions would be 
greatly appreciated.  Thanks!


 _I_______________________________________________________________________I_
(_@_)                                                                   (_@_)
|   |   Raymond Yeung               Internet: Nimbus@uiuc.edu           |   |
|   |                                         rky57514@uxa.cso.uiuc.edu |   |
|   |   EE student at the                                               |   |
|   |   University of Illinois    CompuServe: 70700,1011                |   |
|   |   at Urbana-Champaign                                             |   |
(___)-------------------------------------------------------------------(___)
  I                                                                       I

Newsgroup: sci.electronics
Document_id: 53842
From: ianchan@leland.Stanford.EDU (Ian Hin Yun Chan)
Subject: Need help on...

I need help on 4 components:

BAT85 diode
-----------
I know Digi-key or Newark sells them, but the minimum order is 25!
Does anyone know where I can get smaller orders of this diode, or
an equivalent replacement?

BC546B transistor
-----------------
Ditto for this transistor.

74HC239 chip
------------
Digi-key, Newark and Mouser do not appear to carry ths chip - does anyone
know what this does and where I can obtain it?

YM3623B chip
------------
This Yamaha chip decodes S/PDIF data (from CD or DAT). Where can I obtain
one of these?

Thanks in advance,
- Ian

Newsgroup: sci.electronics
Document_id: 53843
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr20.173742.99726@ns1.cc.lehigh.edu> hl00@ns1.cc.lehigh.edu (HOU-SHENG LIN) writes:
>Well, I'm not too sure if this would be the right place to post this, but
>anyway, here goes:  I was just noticing that some of the current bubblejet
>printers offers up to 360x360 resolution while a lot of lower end laser
>printers only offer 300x300.  However, the laser printers still seems to be
>significantly pricier than the bubblejets... how is this?  Or am I missing
>something about the resolution thing?

Bubblejets often splatter a little bit, whereas LaserJets (given half-way decent
toner, like HP's "Microfine" stuff) don't.  Both produce very good output,
but you don't have to look too closely at the two to tell that LaserJet
output is definitely superior.  

On the other hand, LaserJets which haven't been maintained properly and use
the cheapest toner the owner could find often produce awful output, much
worse than a bubblejet. :-)

One other thing... there are bubblejets, and then there are BubbleJets.
There are a few bubblejets out there that produce rather mediocre output
(such as HP's dinky little BubbleJet), whereas most produce really good
looking output (such as HP's DeskJets).  IBM and Canon both produce some of
the really good style bubblejets.

					---Joel Kolstad

P.S. -- If you're in the market for a portable bublejet printer, I can
highly recommend the HP Portable DeskJet, although I've heard the portable
Canons are good too (I needed PCL support, myself).  With the DeskJet
Portable, you even get an undocumented PCMCIA card slot!

Newsgroup: sci.electronics
Document_id: 53844
From: ravin@eecg.toronto.edu (Govindan Ravindran)
Subject: decoupling caps - onboard

(posted for a friend)
hello there,
        I would like to know if any one had any experience with having
on-board decoupling capacitors (inside a cmos chip) for the power
lines. Say I have a lot of space left im my pad limited design.
any data on the effect of oxide breakdown? any info or pointers
are appreciated.

rs


Newsgroup: sci.electronics
Document_id: 53845
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: EEG Kit?

In article <cantrell.735330560@sauron.msfc.nasa.gov> cantrell@sauron.msfc.nasa.gov (Eric Cantrell) writes:
>Awhile back someone posted some information on where you can get
>kits to build an EEG.  Does anyone remember where you could get
>this.  I'm very interested in getting some info on this.  Thanks 
>in advance.
>
>eric
>
>cantrell@sauron.msfc.nasa      
>

Contact Circuit Cellar Inc., 4 Park St. - Suite 12, Vernon, CT 06066
(203)875-2751, FAX (203)872-2204 and inquire about HAL-4 EEG Biofeedback
Brainwave Analyzer.  

In addition, if you want to build your own system from board-level compo-
nents (biosignal amplifiers, analog isolators and isolated multiplexers)
you can contact The Davron Group,P.O. Box 237, Deerfield, IL  60015
FAX (708)948-9290.

- David


+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53846
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Long distance IR detection

In article <1993Apr20.183416.18744@dres.dnd.ca> sburton@dres.dnd.ca (Stan Burton) writes:
>
>--
>
>I would like to be able to detect the angular position (low accuracy) of an
>IR emitting source at a distance of about 100 meters (more is better) in
>daylight.  The IR source could be emitting a signature; I'm leaning toward
>30 KHz square wave with 50% duty cycle.
>
>I am considering the use of a quadrant detector from Centronic Inc. to give
>information to a pan/tilt head to point the sensor and thus determine the
>angles.  For the source I am considering wazing the heck out of an IR LED(s),
>possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
>current pulses.  At this current the duty cycle of the LED drops to 10% and I
>would need to cycle five of them in turn to get the 50% required.
>
>Has anyone done something like this?
>
>Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
>(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

A method which will directly (almost) provide you with the information that
you require is that which is commonly used for coordinate measurements of 
human body landmarks (eg. the SELSPOT system by SELSPOT AB, Sweden, and the
WATSMART System ??).  These use lateral photoeffect detectors [Lindholm and
Oberg, 1974; Woltring and Marsolais, 1980] to determine the position of a
spot of light projected (using a camera lens) over its surface.  In escence,
the detector is a large photodiode with four cathodes (one on each of the
four sides of the square detector crystal) and a single anode (the back of
the crystal).  A spot of light will produce currents which are proportional
to the position of the spot on the detector's face.  Let's try some ASCII
graphics in 2-D (so the detector has two cathodes to detect linear position)



              -------------------------> 1
             |                       |
             |                       |       |\
           -----   cathode 1         |       |  \
           XXXXX                     ________| +  \
           XXXXX|                            |      \        -------
    light >XXXXX|                            |        \_____ divider __ output
           XXXXX|     |                      |        /      -------
           XXXXX|-----| |--                  |      /           |
           XXXXX|   + |    |         ________| -  /           1 + 2
           XXXXX|         --- gnd    |       |  /
           XXXXX|         \ /        |       |/
           XXXXX| anode              |
           XXXXX                     |
           ----- cathode 2           |
             |                       |
             |                       |
             --------------------------> 2

If the dot of light from the LED is the ONLY source of light, then the position
of the projection is given by this circuit regardless of the level of illumina-
tion (the divider is used to normalize relative to total received power).  When
this circuit is used in the presence of other sources of light, then the way of
"tuning" to it is to sample for a few msec the background signal, light the LED
for an equal time and sample that signal separately.  The difference between
the two is the position of the LED.

Hamamatsu photonics sells linear and 2-D lateral photoeffect detectors, and
they also sell the required signal processing electronics.  The ready-made
systems by SELSPOT and others are NOT cheap ... 

Lindholm, L.E., and K.E. Oberg, "An Optoelectronic Instrument for Remote
On-Line Movement Monitoring", Biotelemetry, 1, 94-95, 1974.

Woltring, H.J., and E.B. Marsolais, "Opto-Electronic (SELSPOT) Gait Measure-
ments in Two and Three Dimensional Space - A Preliminary Report", Bull. Pros-
thetics Research, 46-52, 1980.

Most probably this technique can provide you with a much more accurate
measurement than you need, but I think that its simplicity beats scanning
a quadrant detector with a pan/tilt system until you reach zero difference.

            - David



+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 53847
From: kushmer@bnlux1.bnl.gov (christopher kushmerick)
Subject: infra red position encoders

I am looking for information on infra red based position encoders.

The idea would be to bounce the infrared source off a wall and the device would
read out the distance.

preferable it would be rs-232 addressable.



Any leads?


-- 
Chris Kushmerick
kushmer@bnlux1.bnl.gov
--I found my niche in life, I just didn't fit in.

Newsgroup: sci.electronics
Document_id: 53848
From: pierson@cimill.enet.dec.com (Dave Pierson)
Subject: Re: Swr Meter For Cb Radios

In article <734953838.AA00508@insane.apana.org.au>,
peter.m@insane.apana.org.au (Peter Tryndoch) writes...
>AllThe Devil ReincarnateSWR meter for CB radios
> 
>TD>From: ssave@ole.cdac.com (The Devil Reincarnate)
>TD>Organization: CDAC, WA
>TD>What
>TD>is a good choice for a CB? 1/4 or 1/8 wave?
>TD>  I read the installation instructions on a 1/4 wave antenna,
>TD>and they suggested that I use an SWR to tune it at channel 12
>TD>and channel 32 for a minimum reading.  Question is, why channel
>TD>12 and 32?

>The best antenna is one that will let out the most wave (probably not the 
>best explanation, but the rest makes sense) A one wave will cancell itself 
>out (BTW no such beastie).
	Yes there is.  Not common for CB.  The pattern is different (sort of
	a cloverleaf, with four main lobes.

> The best is a 1/2 wave antenna, followed by 1/4, then 1/8 etc.
	Use of anything under 1/4 wave for transmitting is very uncommon.  (The
	usual "rubber duck" uses a coil to fool itself into looking like a
	quarter wave.
	I reccomend the ARRL Antenna Handbook, or a good basic book.

thanks
dave pierson			|the facts, as accurately as i can manage,
Digital Equipment Corporation	|the opinions, my own.
40 Old Bolton Rd		|I am the NRA
Stow, Mass 01775 USA		|pierson@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles

Newsgroup: sci.electronics
Document_id: 53849
From: chin@ee.ualberta.ca (Jing Chin)
Subject: Need Info on DSP project

I want to start a DSP project that can maniplate music in a stereo cassette. 
Is that any chip set, development kit and/or compiler that 
can equilize/mix music?  Ideally, The system should have D/A A/D converters &
a DSP compiler.  A rough estimate of the cost is greately appreciated.

Thanks in advance.

Regards,
Jing Chin
e-mail address:chin@bode.ee.ualberta.ca

Newsgroup: sci.electronics
Document_id: 53850
From: gray@feline.uucp (Kelly Gray)
Subject: Re: Pinout needed for TIL311

 According to my TI databook, the pinouts for the TIL311 display are as
follows:
 
 Pin 1 - LED supply voltage
 Pin 2 - Latch data input B
 Pin 3 - Latch data input A
 Pin 4 - Left decimal point cathode
 Pin 5 - Latch strobe input
 Pin 6 - Omitted
 Pin 7 - Common ground
 Pin 8 - Blanking input
 Pin 9 - Omitted 
 Pin 10 - Right decimal point cathode
 Pin 11 - Omitted
 Pin 12 - Latch data input D
 Pin 13 - Latch data input C
 Pin 14 - Logic supply voltage, Vcc
 
The logic supply voltage is 5V @ 60-90mA. The LED supply is also 5V, but
it need not be particularly well regulated. The LED drivers on the chip
use a constant current source, so LED intensity is not affected by the
supply voltage.
 

-- 

<o_o>    Kelly Gray
         gray@feline.uucp (preferred)
         gray@admin.humberc.on.ca

Newsgroup: sci.electronics
Document_id: 53851
From: mblock@reed.edu (Matt Block)
Subject: Re: How to the disks copy protected.

In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>---
>
>I was wondering, what copy protection techniques are avaliable, and how
>effective are they?  Has anyone have any experience in this area?
>
>                      With highest regards,
>                           Babak   Sehari.

	Uh oh...
	Umm, there are a number of copy protection schemes.  Some involve
modifying the physical media, and some involve encryption schemes, &c.
	All of the ones that have existed over the course of computing have
been successful for a time.  I recall, however, near monthly releases of new
ways to "crack" the copy protection scheme of the latest releases.  The fact
is, none of them are completely secure, or anywhere near it.  Some are more or
less difficult to crack, and some have already been cracked.
	I guess what I am saying is that your question is difficult, if not
impossible, to answer.  What exactly do you want to know?  Do you need a good
one for a project you are working on?  How secure must it be?  Are you trying
to crack one that someone else has used?  I can probably make suggestions,
assuming the activity is strictly legal.  (In general, it is a BAD idea,
legally, to tamper with copy protection.  It can also lead to corruption of
files which you necessarily do not have back ups of (being as they are copy
protected,) which can be devestating.)  Do you have absolutely no ideas for
practical applications, and are merely curious?
	Please clear up those questions, and I'll try to help as much as I
can.

	Incidentally, the "Uh oh..." at the top is indicative of the dread
anyone who has watched their friends hacking equipment be carted off feels
when they are asked how to hack.  The area you are broaching is wrought with
dangers, many of which include breaking the law, or at least addressing it
(from one side or the other.)

Matt

Newsgroup: sci.electronics
Document_id: 53852
From: moselecw@elec.canterbury.ac.nz (moz [chris moseley])
Subject: Re: Building a UV flashlight

jhawk@panix.com (John Hawkinson) writes:
> My main question is the bulb: where can I get UV bulbs? Do they
> need a lot of power? etc., etc.


he ones I have seen are all fluorescent tubes. Maybe you could find a
small tube to go in one of those hand-held fluoro lanterns?

> One other thing: a friend of mine mentioned something about near-UV
> light being cheaper to get at than actual UV light. Does anyone
> know what he was referring to?

Blue lights. Ultra-violet (by definition?) goes from the blue end of the
spectrum that people see to the radio spectrum (X-rays, cosmic rays etc).

possibly you could get light at the fringe of visibility (which people
with false eye-lenses can see easily, since it's your lenses that soak up
most of the UV), however since most people use UV to get other things
to `glow', and the near-blue is less energetic, it would probably not
work as well, if it worked at all. (lecture on basic atomic physics
fits in here, about electron transitions (quantum leaps) and stuff.

moz

Newsgroup: sci.electronics
Document_id: 53853
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Power, signal surges in home...

In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Douglas S. Rand) writes:
>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:
>
>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>   that a ham would be running that kind of power from a car.  Ham rigs
>
>Not possible either.  You'd need about a 300 amp alternator for
>just the amplifier.  I can just see it.  You need to slow
>down on a downgrade,  so you hit the push to talk button.

Now, that indeed is possible.  A good friend of mine is running about 1 KW
PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
the rig an "electronic brake" since the engine noticeably slows when the
key is down.

My car, unfortunately, has so much computer junk under the hood that it's
astonishingly sensitive to RFI.  If I key a 2W HT over the engine with
the hood open, the car loses timing due to the RF leaking into the 
distributor pickup.  Very poor design.

I will, however, point out that ham radio operators are usually quite willing
to help when interference is detected.  Remember that any interference is
wasted power; if I put out 1W in the TV band, that's 1W that I am not putting
out in the band I am trying to transmit on, and 1W can often be the difference
between a nice card hanging on the wall, and nothing.  CBers, however, are
usually not as helpful.  Most illegal CBers, however, will stop operation
when you inform them of a problem.  The rest of them will stop operation when
you inform the local FCC office of the problem (in writing, and giving details
and addresses).

>Last, you can usually tell ham radio vs. CB.  Ham operators are
>required to declare their call (sign) every so many minutes (no more
>than 10).  So if you hear "This is WA1QT" or some other call starting
>with A, W or K and no more than 6 total characters, you heard a ham.
>CB'ers probably won't sign (I don't know that they're even required
>to) and fire/police have other private ids.

Good advice.  Hams will frequently give their call, and will never use
a "handle."  They are less apt to use immense amounts of profanity as well,
but that's not to say that they don't from time to time.  
--scott

Newsgroup: sci.electronics
Document_id: 53854
From: avm1993@sigma.tamu.edu (MAMISHEV, ALEXANDER VALENTINO)
Subject: digital voltmeter - how does it work?

     Hello, 

   Let me introduce a problem:

   When I measure a sinusoidal wave (voltage) with a digital voltmeter, using 
AC mode, my output is an rms value (a peak value over 2 squared). / Right? / 
   When I measure a square wave in the same mode (AC), my output is equal 
to a peak value, actually, to the upper flat boundary of the wave.
   I assumed, that a digital voltmeter makes some kind of integration of the 
input value, and divides it over the wave period. / Right?/
   Now, I used it to measure the same  square wave as above, but distorted 
by high-frequency harmonics. Ideally, output should be the same, but...
The output value was only about 10% of the previous one! 
   Why? What is the nature of this output value? What does the voltmeter 
actually measure? And what does it show?  

   Related question (less important to me):
   What are advantages and disadvantages of digital voltmeters to compare with 
analog ones? 

   Thank you for your attention, you could mail me your opinion at
avm1993@zeus.tamu.edu or open a discussion here. I would appreciate either 
way.


Alexander V. Mamishev

____________________________________________________________________________
Power System Automation Laboratory    <>   phone office (409) 845-4623    
Department of Electrical Engineering  <>   phone home   (409) 846-5850
Texas A&M University                  <>   fax   (409) 862-2282
College Station, TX 77843, USA        <>   Internet: avm1993@zeus.tamu.edu
----------------------------------------------------------------------------


Newsgroup: sci.electronics
Document_id: 53855
From: f92anha@fy.chalmers.se (Anders Hammarquist)
Subject: Re: Need to find out number to a phone line

In article <23321@mindlink.bc.ca> Sean_Oliver@mindlink.bc.ca (Sean Oliver) writes:
>> Joseph Mich Krzeszewsk writes:
>>         890 the phone company will read the number of the phone you are on
>
>Where I live, I use BCTEL. The number to dial is 211 for the same result.
>

In NY City, the number to dial is 958... It seems to be different in different
areas.

Anders

Newsgroup: sci.electronics
Document_id: 53856
From: gunnarh@dhhalden.no (GUNNAR HORRIGMO)
Subject: Re: How to the disks copy protected.

In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:

>I was wondering, what copy protection techniques are avaliable, and how
>effective are they?  Has anyone have any experience in this area?
>
>                      With highest regards,
>                           Babak   Sehari.

One of the easiest, and really very used ways of copyprotection, is to mark 
a specific sector on the installation disk bad. This is very easy to get 
around, though, if you have any knowledge of hw-hacking, but most 'normal' 
users (yes those lowly key-punchers) don't. Whatever you do, please do 
_not_ use a hardware key. These were very popular a few years ago, and they 
STINK!!

MAIL-mail: gunnarh@sofus.dhhalden.no    SNAIL-mail: Gunnar Horrigmo
           gunnarh@fenris.dhhalden.no               Oskleiva 17
                                                    N-1772 Norway
----------------------------------------------------------------------
Disclaimer: The above posting may seem like insignificant rubbish at 
first glance, but if you read between the lines, you will be 
surprised to discover the annals of Burt Bacharach, world peace, 
Oxford Advanced Readers Dictionary, quantum physics made easy, and an 
easy-to-use step-by-step walkthrough on how to make a time travelling 
device that actually works.

Newsgroup: sci.electronics
Document_id: 53857
From: edhall@rand.org (Ed Hall)
Subject: Re: Building a UV flashlight

In article <C5r6Lz.n25@panix.com> jhawk@panix.com (John Hawkinson) writes:
>One other thing: a friend of mine mentioned something about near-UV
>light being cheaper to get at than actual UV light. Does anyone
>know what he was referring to?

I don't want to get into a semantic argument, but contrary to some other
postings "near UV light" /is/ "actual UV light."  The "near" means that
it is close to the visible spectrum (i.e. of relatively long wavelength),
not that it is "nearly UV."  (I'm sure you can figure out now just what
"far UV" is.)

Regular incandenscent flashlight bulbs emit tiny amounts of UV in the
near end of the spectrum, such that a filter can be used to remove the
visible light and thus create a weak UV source.  Stronger sources are
going to require gas (probably mercury vapor) discharge tubes (such as
fluorescent tubes with UV phosphor).  Be careful, though; strong UV
sources can cause physiological damage, especially to the eyes.  The
shorter wavelengths are the most dangerous.

It wouldn't project a beam like a flashlight, but replacing the tubes
in a portable fluorescent lantern with UV tubes would be a relatively
cheap way to create a portable source.  It would be bright enough to
be useful, but not dangerously so.

		-Ed Hall
		edhall@rand.org

Newsgroup: sci.electronics
Document_id: 53858
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Power, signal surges in home...

kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:

>My car, unfortunately, has so much computer junk under the hood that it's
>astonishingly sensitive to RFI.  If I key a 2W HT over the engine with
>the hood open, the car loses timing due to the RF leaking into the 
>distributor pickup.  Very poor design.

There was a news article a little while ago reporting a type of car (was
it a Volvo?) was found to stall if you used a certain brand/model of cellular
phone in it.  I seem to remember the car was recalled to fix the problem.

Hmmmmm... this has possibilities:
If the police are in pursuit of a vehicle, maybe they can bombard it with
high energy RFI.  :-)


Newsgroup: sci.electronics
Document_id: 53859
From: johnh@macadam.mpce.mq.edu.au (John Haddy)
Subject: Re: Help wanted

In article <1993Apr20.071549.24839@csc.canberra.edu.au>, u934132@student.canberra.edu.au (Ogawa / Taro Stephen (ISE)) writes:
|> Could someone please tell me if a 1/4 decoder is the same as a 1 to 4
|> demultiplexer. I know how to link 2 of these to get an 8 output circuit,
|> but how do I link 5 of these to make a 1/16 multiplexer. Sorry if this
|> seems like a lame question, but I'm only a newbie to electronics, and I
|> have to do this circuit. Please make any mail as droolproof as possible.
|> 
|> 				 Thanx,
|> 					Taro Ogawa
|> 					(u934132@student.canberra.edu.au)

A 1 of 4 decoder need not be the same as a 1 to 4 demultiplexer, although
many commercial SSI implementations allow you to use one as such. Strictly,
a 1 of 4 decoder need only take two lines in and make one output change
state, according to the inputs.

A demux, on the other hand, uses two control inputs to determine which
of four outputs will reflect the state of the input signal. So there are
three inputs required.

A decoder can be used as a demux if it is equipped with an output enable
input, since this can be used as the data input (e.g. when high, all
outputs are high; when low, only the selected (by control inputs) output
will be low).

An eight way decoder is created by using the high order bit (bit 2) to
select which of two four way demuxes is enabled. Thus you achieve your
aim of having only one output of eight reflecting the input bits. Note
that this method cannot be used to create a true eight way demux, since
you have no data input (the enable line on a four way decoder) left
once you commit the enable lines to their intended purpose.

A sixteen way decoder obviously requires four, four-way decoders, plus
a mechanism to enable only one of the four at a time. Therefore, use
the fifth decoder, attached to the two high order bits, to provide the
four enable lines.

Of course, the two low order bits must be connected in parallel to the
four final stage decoders.

Please give me the credit when you submit your homework.

JohnH

----------------------------------------------------------------------------

      |  _  |_   _   |_|  _   _|  _|              Electronics Department
    |_| (_) | | | |  | | (_| (_| (_| \/           School of MPCE
    ---------------------------------/-           Macquarie University
                                                  Sydney, AUSTRALIA 2109

    Email: johnh@mpce.mq.edu.au, Ph: +61 2 805 8959, Fax: +61 2 805 8983

----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53860
From: baden@inqmind.bison.mb.ca (Baden de Bari)
Subject: *]] MOSFET help...

 
        Since I'm not all too keen on this area of hooking them up, I'm 
asking for help.  I know better than to hook a 12v, 1a stepper line to 
one, unless it can take it; however what about if I've got a 24-60v 
stepper.  What sort of curent limmiting circuitry would be involved (a 
small schematic would probably be helpfull).  
        Also, I've looked into the TIPC2701N by TI, and I was wondering 
if I should use the same suggested (by you replying to this message) 
current limiting circuitry on each of the 7 mosfets in the package as 
that illustrated in the schematic (which you the replyer would hopefully 
help me with).
 
                                ... hmm... different request... 
 
                Thanks.

 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

baden@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 53861
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: minimal boolean circuit

In article <1993Apr9.041505.8593@ringer.cs.utsa.edu> djimenez@ringer.cs.utsa.edu (Daniel Jimenez) writes:
>Suppose we have a boolean function which is a minimal sum-of-products
>(derived from a K-map or something), like this:

>f(a,b,c,d) = bc'd' + acd' + abc' + ab'c
>
>The books on logic design I have consulted all seem to imply that this
>is where the analysis ends  ...  But by factoring out the
>`a' term in the function, we can get fewer gates:

>f(a,b,c,d) = bc'd' + a(cd' + bc' + b'c),

>which yields 9 gates. 

	Yes, but... the minimization of gates is important in part
because of TIMING considerations.  A TTL gate has the basic structure
of AND/OR/INVERT, and an inversion of a sum of a product is just
exactly ONE gate delay.  The reason to find a minimal sum of products
is that this matches a hardware optimization.

	A positive-OR gate (such as the 9-gate solution uses) has
TWO gate delays (and there's another gate delay in the second term)
so that the second solution, while simpler in logic symbols, can 
be expected to be something less than optimal in the real world.
ECL is similar to TTL, in that it can support an OR/AND
gate with the minimum delay (unlike TTL, you get both true and
inverse outputs for 'free' when using ECL).

	PALs are basically large programmable AND/OR/INVERT
gates (with your choice of internal connections between the
various sections, and perhaps some latches), so a minimum sum
of products ALSO is a way to shoehorn a logic design into 
a few PALs.  It's not comparably easy to design with a minimization
of logic gates, but some software packages claim to allow you to
do so, and will take just about any mess of gates (as a nodelist
with 74xxx series logic ICs) and produce a description of
a logic cell array to do the same job.  Xilinx's XACT software
does this by treating each logic block as a macro, and expanding
it all out, then simplifying.

	John Whitmore

Newsgroup: sci.electronics
Document_id: 53862
From: blockley@csu.murdoch.edu.au (Adrian Blockley)
Subject: integrated cct-type UM82C452L manufac by UMC.

where can I buy 1 or 2 of these chips (pref in Australia)?
What is name and address of `UMC'?

Dan

--

----------------------------------------------------------------------
Adrian Blockley                    ! I may say something profound   
Environmental science              ! here one day.                  
Murdoch University                 !                          
Western Australia, 6153            !                               
blockley@essun1.murdoch.edu.au     !                                
phone 09-360 2737                  !
----------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53863
From: jeff@nsr.hp.com (Jeff Gruszynski)
Subject: Re: digital voltmeter - how does it work?

MAMISHEV, ALEXANDER VALENTINO (avm1993@sigma.tamu.edu) wrote:
:      Hello, 
: 
:    Let me introduce a problem:
: 
:    When I measure a sinusoidal wave (voltage) with a digital voltmeter, using 
: AC mode, my output is an rms value (a peak value over 2 squared). / Right? / 
:    When I measure a square wave in the same mode (AC), my output is equal 
: to a peak value, actually, to the upper flat boundary of the wave.
:    I assumed, that a digital voltmeter makes some kind of integration of the 
: input value, and divides it over the wave period. / Right?/
:    Now, I used it to measure the same  square wave as above, but distorted 
: by high-frequency harmonics. Ideally, output should be the same, but...
: The output value was only about 10% of the previous one! 
:    Why? What is the nature of this output value? What does the voltmeter 
: actually measure? And what does it show?  


Re: RMS readings

Unless the DVM *says* it's measuring RMS, it's probably Average voltage.
The input is diode rectified and measured as DC.  If it says it's RMS
and but measures square/triangle/etc.  incorrectly, it's measuring
average and multipling by a correction that's *only* true for sine waves
(i.e.  Vave*(0.707/0.63) = Vrms).  If you want correct RMS for (most)
any waveform, you need a "True-RMS" DVM/DMM which literally does the
Root-Mean-Square calculation in either analog or digital circuitry.

: 
:    Related question (less important to me):
:    What are advantages and disadvantages of digital voltmeters to compare with 
: analog ones? 

The last significant advantage of analog (IMO) ** was ** being able to
"see" the signal if it was changing over time (e.g.  checking
electrolytic capacitors).

Anymore, most DMM have bargraphs, etc. that duplicate this.

: 
:    Thank you for your attention, you could mail me your opinion at
: avm1993@zeus.tamu.edu or open a discussion here. I would appreciate either 
: way.
: 
: 
: Alexander V. Mamishev
: 
: ____________________________________________________________________________
: Power System Automation Laboratory    <>   phone office (409) 845-4623    
: Department of Electrical Engineering  <>   phone home   (409) 846-5850
: Texas A&M University                  <>   fax   (409) 862-2282
: College Station, TX 77843, USA        <>   Internet: avm1993@zeus.tamu.edu
: ----------------------------------------------------------------------------
: 

--
================================================================================
Jeff Gruszynski
Semiconductor Test Equipment
Systems Engineer
Hewlett-Packard
================================================================================
(415) or T 694-3381
jeff@hpmvd061.nsr.hp.com
jeff@hpuplca.nsr.hp.com
================================================================================

Newsgroup: sci.electronics
Document_id: 53864
From: dnewman@lynx.dac.northeastern.edu (David F. Newman)
Subject: arcade style buttons and joysticks

Hi there,
Can anyone tell me where it is possible to purchase controls found
on most arcade style games.  Many projects I am working on would
be greatly augmented if I could implement them.  Thanx in advance.

-Dave
dnewman@lynx.dac.northeastern.edu


Newsgroup: sci.electronics
Document_id: 53865
From: elliott@optilink.COM (Paul Elliott)
Subject: Re: Analog switches/Balanced Demodulators

In article <msf.734832494@skaro> msf@skaro.as.arizona.edu (Michael Fulbright) writes:
>I am trying to build a synchronous demodulator and I've hit a snag.
>In my application I want to be able to change the gain of an
>op amp amplifier from 1 to -1, controlable via a digital input.
>The most obvious way I've come up with is to use analog switches
>to adjust the gain of the op amp. The only analog switch I have
>experience with it the 4066. Unfortunately I want to switch an
>AC signal which goes from about -5V to 5V, and the 4066 is only
>for positive signals.
>[...]
> I have a carrier signal which varies between 0V and +5V. I want
>to demodulate an input signal by feeding the input signal thru a
>amp with a gain of 1 when the carrier is at +5V, and thru a amp
>with a gain of -1 when the carrier is 0V. The output is then
>low pass filtered. I believe this is called lock in detection as well
>as synchronous demodulation.

Look at the 4053.  This is a triple 2-to-1 transmission-gate analog
multiplexer, with positive and negative power supplies (can be run
from a single-ended supply as well).  With dual supplies, the logic
inputs still range from ground (0 Volts) to VDD.

This is a neat (well, I think so) design for a switchable-polarity
amplifier:

                 +-----/\/\/\-------+
                 |                  |
                 |    /--------\    |
INPUT -+-/\/\/\--+----| -      |    |
       |              |  opamp |----+------- OUTPUT
       +-/\/\/\--+----| +      |
                 |    \--------/
                 |
CONTROL	---------X (analog switch)
                 |
                 |
                ---
                GND

All resistors are equal-value.  When the analog switch is closed,
the amp is inverting-gain-of-one.  With the switch open, it is
non-inverting-gain-of-one.  You can clean up the circuit to trim
out input offset current if this hurts the balance (this would show
up as carrier feed-through).

For high frequencies, the slew-rate of the opamp might cause problems,
especially if it isn't symmetrical (and it usually isn't).

-- 
--------     Paul Elliott - DSC Optilink - Petaluma, CA USA      ----------
    {uunet,pyramid,tekbspa}!optilink!elliott -or- elliott@optilink.com
       "I used to think I was indecisive, but now I'm not so sure."


Newsgroup: sci.electronics
Document_id: 53866
From: rogerw@world.std.com (Roger A Williams)
Subject: Re: 68HC16 public domain software?

Doesn't Motorola AMCU have something on the BBS yet? (512-891-3733)

Newsgroup: sci.electronics
Document_id: 53867
From: sehari@iastate.edu (Babak Sehari)
Subject: Re: How to the disks copy protected.

In <1993Apr20.230749.12821@reed.edu> mblock@reed.edu (Matt Block) writes:

>In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>>---
>>
>>I was wondering, what copy protection techniques are avaliable, and how
>>effective are they?  Has anyone have any experience in this area?
>>
>>                      With highest regards,
>>                           Babak   Sehari.

>	Uh oh...
>	Umm, there are a number of copy protection schemes.  Some involve
>modifying the physical media, and some involve encryption schemes, &c.
>	All of the ones that have existed over the course of computing have
>been successful for a time.  I recall, however, near monthly releases of new
>ways to "crack" the copy protection scheme of the latest releases.  The fact
>is, none of them are completely secure, or anywhere near it.  Some are more or
>less difficult to crack, and some have already been cracked.
>	I guess what I am saying is that your question is difficult, if not
>impossible, to answer.  What exactly do you want to know?  Do you need a good
>one for a project you are working on?  How secure must it be?  Are you trying
>to crack one that someone else has used?  I can probably make suggestions,
>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>legally, to tamper with copy protection.  It can also lead to corruption of
>files which you necessarily do not have back ups of (being as they are copy
>protected,) which can be devestating.)  Do you have absolutely no ideas for
>practical applications, and are merely curious?
>	Please clear up those questions, and I'll try to help as much as I
>can.

>	Incidentally, the "Uh oh..." at the top is indicative of the dread
>anyone who has watched their friends hacking equipment be carted off feels
>when they are asked how to hack.  The area you are broaching is wrought with
>dangers, many of which include breaking the law, or at least addressing it
>(from one side or the other.)

>Matt

I have written a program and I want to market it.  I would like certain degree
of protection, since my main custmers are individuals and not the 
cooperations.   I know laser hole burning method, and hardware key method,
however, my  software is going to cost only $15.00, so I can not afford that.
Also, at this low price I can not afford people make too many copy of my
software. Well, I guess say upto %20 illigal copying is ok by me.

However, I do not want someone to get a copy of PCTools and copy my software.  
Off course, I never meant to forbid the true hackers from copying, since they
can develope a better program anyway.

                      With highest regards,
                           Babak   Sehari.


-- 

Newsgroup: sci.electronics
Document_id: 53868
From: patter@dasher.cc.bellcore.com (patterson,george r)
Subject: Re: Power, signal surges in home...

In article <1993Apr20.232804.24632@mprgate.mpr.ca> vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>
>>My car, unfortunately, has so much computer junk under the hood that it's
>>astonishingly sensitive to RFI.  
>
>Hmmmmm... this has possibilities:
>If the police are in pursuit of a vehicle, maybe they can bombard it with
>high energy RFI.  :-)

Right. So all the cops will be buying antique muscle cars for chase cars;
otherwise the *police* cars will die too!

-----------------------------------------------------------------------
                    | To get the attention of a large animal, be it an
                    | elephant or a bureaucracy, it helps to know what
George Patterson -  | part of it feels pain. Be very sure, though, that
                    | you want its full attention.
                    |                            Kelvin Throop
-----------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53869
From: dale@access.digex.com (Dale Farmer)
Subject: Re: Building a UV flashlight

John Hawkinson (jhawk@panix.com) wrote:
: Yes, I know it sounds crazy. Call it an urge. Call it what you want.
: Just don't ask why :-)

: Anyway, I'd like to build a UV flashlight, cheaply. "flashlight" means
: it should be reasonably portable, but could have a power pack if
: necessary.

: My main question is the bulb: where can I get UV bulbs? Do they
: need a lot of power? etc., etc.

: I'm not too concerned with whether it's long-wave or short-wave
: (but hey, if anyone has a cheap source of bulbs, I'll take both).

	Check out a medical supply catalog, the thing you are looking for
is called a woods lamp (so you can check for woods sign, certain skin
conditions flourecse (sp) under UV light)  They come in disposable
penlight like types and larger ac powered types.  It is also used in eye
examinations, a flourescent dye is introduced to the surface of the eye,
then UV is shined on it, shows up scratches and abrasions very clearly
that would otherwise be very difficult to detect.  (for the completest the
dye is called flouescien, and in normal light appears orangish, and leaves
a mild burning sensation to the eye for 10-15 minutes, until the tears
flush it all out.  

Have fun.

--Dale Farmer




Newsgroup: sci.electronics
Document_id: 53870
From: umlangston@msuvx1.memst.edu (Mark C. Langston)
Subject: _negative_ logic high?

  This may sound like a simple-minded question, but this is the first time
I've ever had a need for this:

I've been designing some relatively simple chip circuits based on things
like photoresistors (you know, no light to photoresistor, emit a logic
high, etc.).

Anyway, I've got some servos lying around, and I wanted to do some things
with them using digital logic.  I know all about having to pulse the signal
and everything, I just have one problem:  I'm assuming I need a negative
(yes, negative) logic high to get the thing to turn in the direction 
opposite the direction it would turn under normal logic high.

Is a negative logic high (I've seen this in schematics) the same thing as
an active low, or what?  I'm not using a bi-polar power source, so how
would I get a negative logic high out of this thing?  I need to have all
three signals available:  Logic high, logic low, and negative logic high.

Any help would be greatly appreciated.  Also, please reply via email, as I
never seem to have time to read this (or any other) group lately.

Thanks much,
-mark

umlangston@memstvx1.memst.edu




Newsgroup: sci.electronics
Document_id: 53871
From: randyd@csd4.csd.uwm.edu (Randall Elton Ding)
Subject: Re: ADCOM GTP500II IR sensor & repeater spec's?

In article <1r1996INNijp@hp-col.col.hp.com> johnr@col.hp.com (John T. Rasper) writes:
>Does anyone know the details of the interface (5 wire din) for the
>IR remote sensor & (2 wire IR repeater) for the ADCOM GTP-500II
>preamp?  The ADCOM part numbers are the XR-500II, SPM-500II, and 
>IRA-500II.
>
>A cursory physical examination of the pre-amp connector indicates
>that the connector (5 pin din) may provide: (Viewed from connector front)
>
>      |
>   5     1     (pin ?) +?v @ ???mA
>    4   2      (pin ?) +/-?v @ ???mA
>      3        (pin 3) Signal Ground
>               (pin ?) Demodulated signal ?V-pp, ? polarity, ? mA drive
>               (pin ?) Signal to drive repeater LED (drives through 150ohm
>                       resistor) ?V-pp
>
>I assume that the repeater connectors (mini-plugs) drive the IR repeater
>LED's directly.  True?
>
>Can anyone fill in the ?'s.  Thanks.
>

Here's the scoop.  When you get your home brew receiver working, would
you be willing to share it with the rest of us?  I always wanted to
build my own but never have the time to fool around and design it.

pin 1:  signal ground
pin 2:  signal
pin 3:  always hot +6 volts
pin 4:  +6 volts, hot only when preamp is turned on
pin 5:  infrared repeater connectors

The infrared repeater jacks on the back of the preamp are not connected
to anything inside the preamp except the 5 pin connector pin #5.  There
is a 150 ohm resistor between the two jacks, with a 1.5K from pin 5 to
ground.

The signal pin #2 in the preamp is summed with the built in IR receiver.
They use a chip called CX20106A and a BJT to amplify the signal.  I would
imagine the logical way would be to duplicate this circuit and use
it as the external receiver.

If you need more info, let me know.

Randy      randyd@csd4.csd.uwm.edu



Newsgroup: sci.electronics
Document_id: 53872
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: Radar detector DETECTORS?

>>>  Are any brands "quieter" than others?

>Yes some radar detectors are less detectable by radar detector
>detectors. ;-)

I have a Bel-966.
I just looked at the manual yesterday... and it does indeed claim to be
undetectable by RDD's.


Pat

Newsgroup: sci.electronics
Document_id: 53873
From: gerrit@laosinh.stgt.sub.org (Gerrit Heitsch)
Subject: Re: 6551A and 6551 compatibility

In article <C5owvs.pr@world.std.com>, Internet Surfer writes:

> Does any one know if the 6551 is timing/pin compatible with the 6551.. 

No, the 6551A is able to operate in a 2 MHz system, the 6551 can only
take 1 MHz without problems.

If you see a 8551 made by MOS or CSG, take it, its a 6551A.

> It seems the 6551 has in iheirent bug with cts/rts handshaking and i need
> a suitable pin replacement to put in my serial card... possibly a buffered
> version perhaps?

I know no fixed version of the 6551. There are different possibilities
to work around this bug. The easiest is to tie _CTS to GND and
use _DSR or _DCD as _CTS. It should be easy to fix the software,
_DSR is bit 6 and DCD ist bit 5 of the Status Register (Read 6551
with RS1 = low and RS0 = high).

Using the _CTS-line can lead into big trouble. The 6551 _instantly_
stops transmission if _CTS goes high. This means, that you may
get only a half byte...

Gerrit

-- 
         Gerrit Heitsch  Moenchweg 16  7038 Holzgerlingen  Germany
  Logical adresses: UUCP: gerrit@laosinh.stgt.sub.org FIDO: (2:2407/106.9)
If we will ever be visited by Aliens, it will be very hard to explain, why a
 lifeform, that is intelligent enough to build atomic weapons can be stupid
   enough to do it. (taken from GEO special about space, page 88-91)

Newsgroup: sci.electronics
Document_id: 53874
From: gerrit@laosinh.stgt.sub.org (Gerrit Heitsch)
Subject: Re: What's a good IC for RS232 -> TTL signals??

In article <C5nz60.99z@scraps.uucp>, Frank Holden KA3UWW writes:

> >I'm looking for an IC that will convert RS232 voltage levels to TTL voltage 
> >levels.  Something relatively inexpensive would be nice, too.  Anyone have
> >a suggestion??  Thanks.
> 
> Well it looks as if Digi-Key sells a chip with the number ICL232 that does what
> you want.  They are selling it for about $3.50...

Are you sure that he needs a two way converter? If he wants only
RS232->TTL I would suggest the MC1489, its very cheap (0.80 DM in
Germany). This chip needs only +5V. The MC1488 TTL->RS232-Converter
uses +12V and -12V.

BTW... The MAX232 and compatibles seem to be expensive in the USA...
I paid 2.95 DM for a ITS80272 (made by Harris), its absolutely
compatible with the MAX232 or the ICL232.

Gerrit

-- 
         Gerrit Heitsch  Moenchweg 16  7038 Holzgerlingen  Germany
  Logical adresses: UUCP: gerrit@laosinh.stgt.sub.org FIDO: (2:2407/106.9)
If we will ever be visited by Aliens, it will be very hard to explain, why a
 lifeform, that is intelligent enough to build atomic weapons can be stupid
   enough to do it. (taken from GEO special about space, page 88-91)

Newsgroup: sci.electronics
Document_id: 53875
From: rmah@panix.com (Robert Mah)
Subject: Re: electronic parts in NYC?

In <FRITZM.93Apr20225937@sun.panix.com> fritzm@panix.com (Fritz Mueller) writes:
>I just moved to NYC and wondered if there are any electronics hackers
>out there who could point me to places in NYC that sell individual
>electronic components (switches, pots, transformers, caps,
>...

Try Cables and Chips ... let me dig out a reciept ...

Here we are...

Cables & Chips at 121 Fulton Street, that's near South Street Seaport and 
Wall Street.  Phone is 212-619-3132 and 800-843-4117.

However, when ordering there, be VERY exact or there's a good chance they'll 
screw up.  Otherwise, they're pretty good, and they deliver too.

Cheers,
Rob
-- 
[----------------------------------------------------------------------]
[ Robert S. Mah   | Voice: 212-947-6507   | "Every day an adventure,   ]
[ One Step Beyond | EMail: rmah@panix.com |  every moment a challenge" ]
[----------------------------------------------------------------------]

Newsgroup: sci.electronics
Document_id: 53876
From: fritzm@panix.com (Fritz Mueller)
Subject: electronic parts in NYC?

Hey all:

I just moved to NYC and wondered if there are any electronics hackers
out there who could point me to places in NYC that sell individual
electronic components (switches, pots, transformers, caps,
transistors, etc.)  "Radio Shack" doesn't count (they have almost no
selection, and their prices are outrageous!)

I have particular interest in audio components (amplifier IC's, power
MOSFETS, output transformers, tubes and tube sockets, pan pots,
faders, etc.)

I have checked out a lot of 48th street and Canal street so far with
no luck.  Am I missing places, looking in the wrong place, or do I
have to resort to mail order?

					thanks in advance,
					  --FritzM.

Newsgroup: sci.electronics
Document_id: 53877
From: stevens@madvlsi.columbia.edu (Andy Stevens)
Subject: Re: decoupling caps - onboard

In article <1993Apr20.173652.762@jarvis.csri.toronto.edu>, ravin@eecg.toronto.edu (Govindan Ravindran) writes:
|>         I would like to know if any one had any experience with having
|> on-board decoupling capacitors (inside a cmos chip) for the power
|> lines. Say I have a lot of space left im my pad limited design.
|> any data on the effect of oxide breakdown? any info or pointers
|> are appreciated.

DEC did this on their new alpha chip.  I'm sure you could call them up
and ask them how they did it (haha).

Actually, there are some details in their article in IEEE Journal of
Solid-State Circuits.  I think it was sometime around Nov.  1992.

--andy s.

Newsgroup: sci.electronics
Document_id: 53878
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: How to the disks copy protected.

In article <sehari.735357542@du139-213.cc.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>
>I have written a program and I want to market it.  I would like certain degree
>of protection, since my main custmers are individuals and not the 
>cooperations.   I know laser hole burning method, and hardware key method,
>however, my  software is going to cost only $15.00, so I can not afford that.
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.
>
>However, I do not want someone to get a copy of PCTools and copy my software.  
>Off course, I never meant to forbid the true hackers from copying, since they
>can develope a better program anyway.

I wouldn't bother with the copy protection, if I were you.  If you program
is any good, the pirates will have stripped the protection and will be
distributing the stripped version is well under a week.

Hardware methods prevent J. Random Loser from using his Copy II PC to pirate 
your software, but doesn't stop anyone who knows a few people with enough 
connections to "real" pirates who _will_ be able to defeat your "check for the 
hole" code.

You may want to price your software (depending on what it is) a tad
higher... a price change from $15 to $25 probably would turn off very few
potentials buyers, and that way you could tolerate more pirates (whose
numbers don't change with the price).

As for the 20% pirating figure... ha, ha.  Of course, a lot of pirates just
have this "thing" about having pirated software, even if they never use it,
so perhaps that really wouldn't count towards 20%.  Even so, 20% is awfully
low.


					---Joel Kolstad

P.S. -- I assume you're talking PC software.  If you're talking UNIX,
HP-48, or something else somewhat obscure, copy protection might be a
slightly more viable alternative.

Newsgroup: sci.electronics
Document_id: 53879
From: mhald@lynx.dac.northeastern.edu (Mark Hald)
Subject: Re: Dayton Hamfest

I booked a hotel (Red Roof Inn) last week in Cincinnati (Blue Ash, which
is at the northern tip of the metro. Cincy area).  I chose it for a few
reasons.
  1.  All hotels in and near Dayton were booked solid.
  2.  This hotel is only costing $28/night.
  3.  It was one of about 4 rooms left on the night I reserved.
  4.  Cincinnati probably has more to to at night than Dayton.  I intend
      to hit the riverboat entertainment at dusk!

If anyone has other suggestions for nightlife, please let me know of
other hot spots.  Thanks!

Mark

Newsgroup: sci.electronics
Document_id: 53880
From: skipper@traider.ersys.edmonton.ab.ca (Mark Bevan)
Subject: Re: Need to find out number to a phone line

alee@ecs.umass.edu writes:

> 
> Greetings!
>       
>         Situation:  I have a phone jack mounted on a wall.  I don't
>                     know the number of the line.  And I don't want
>                     to call up the operator to place a trace on it.
> 
>         Question:   Is there a certain device out there that I can
>                     use to find out the number to the line?
>         Thanks for any response.
>                                                     Al
> 
>   

Dial 511 and it sound tell you the number.

---
skipper@traider.ersys.edmonton.ab.ca (Mark Bevan)
Traiders of the Lost .ARC! - Edmonton, Alberta, Canada

Newsgroup: sci.electronics
Document_id: 53881
From: cbruno@wpi.WPI.EDU (Christopher James Bruno)
Subject: Coil

Hey everyone, I'm new to this  newsgroup so please excuse me if this is a 
dumb question....I want to build a crossover for my stereo and I need
a coil with an inductance of 6.8mH (actually I need 4).  I was wondering
if anyone knew where I could buy these or how to make these.  I've called
many places and no one I can find sells them.  If you have the answers just
E - mail me....
Thanks in advance....
Chris




Newsgroup: sci.electronics
Document_id: 53882
From: dave@imax.imax.com (Dave Martindale)
Subject: Re: A question about 120VAC outlet wiring.

jeh@cmkrnl.com writes:
>
>Hmmm.  How are those orange "isolated ground" outlets (often used in
>computer rooms) wired?  

They require two separate grounds.  One ground goes to the ground pin
of the outlet, and the other ground wire is connected to the outlet's
mounting tabs (and thus grounds the box and faceplate screw and metal
faceplate, if any).

The box/faceplate ground goes to the normal distribution panel ground.
The outlet ground-pin wire is generally connected to an insulated
busbar in the distribution panel which is, in turn, connected to
the building-entrance main ground by its own wire.

So the two separate ground systems are connected together at the
building's service entrance.  But one is also connected to every
grounded piece of electrical equipment in the whole building,
while the isolated ground is shared only by the equipment plugged
into isolated-ground outlets of that panel.  If someone happens
to accidentally short one phase of a 600V feeder to ground,
the main building ground is likely to have a lot of noise on it
until the breaker trips or the fuse blows, while the isolated
ground will remain relatively noise-free.

Newsgroup: sci.electronics
Document_id: 53883
From: mtearle@gu.uwa.edu.au (Mark Tearle)
Subject: Re: Looking for Electronics Dept Info in Austrailia

hjkim@hyowon.pusan.ac.kr (Hojoong Kim) writes:

>Hi Netters!

>I am looking for the list of universities in Austrailia, which has electronics department. 
>I am considering to spend a year for research in Austrailia about communication area. I am interested in Mobile communication areas and spread spectrum communications etc. 
>But I don't have any information about Austrailian Universities.
>Can anybody recommend a good university in communication area?
>Any comments will be welcomed!

Can I suggest the University of Western Australia in Perth.
The weathers great, the people are great and our Electronic Engineering department is great.
I am a first year student here ... so I don't know much about what projects but I do know they have a good reputation in the fields of dsp and communications.  Ever heard of QPSX?  The people who own are ex-UWA ... so that gives an indication of what the department is like.

For more information
email: yianni@swanee.ee.uwa.edu.au
with the above request and he should be able to tell some more info

or write

Department of Electrical and Electronic Engineering
University of Western Australia
Stirling Highway
CRAWLEY 6009
Western Australia
Australia


Yours
Mark

mtearle@tartarus.uwa.edu.au
--
#***********************************************************************#
#  Mark Tearle                         |                                   #
#                                      |     
#  email: mtearle@tartarus.uwa.edu.au  |     

Newsgroup: sci.electronics
Document_id: 53884
From: mtearle@gu.uwa.edu.au (Mark Tearle)
Subject: Re: Need to find out number to a phone line

Well here in Australia you dial 
11544
to get the number read back to you
if you live in the country include the area code of the nearest capital city
eg for wa 09 11544

Yours
Mark

--
#***********************************************************************#
#  Mark Tearle                         |                                   #
#                                      |     
#  email: mtearle@tartarus.uwa.edu.au  |     

Newsgroup: sci.electronics
Document_id: 53886
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: ATARI 2600 Processors

In article <93110.125951PCA103@psuvm.psu.edu> <PCA103@psuvm.psu.edu> writes:
>Does anyone know what processor the Atari 2600 used? What I'm looking for is th
>e pin-outs for the Atari 2600.... the schematics for it it... does anyone have
>any idea where I could find this or any related information? This is very impor
>tant. Also, are the ROM chips that were used fo rthe 2600 games still available
>, or were they propreitary? Please email me with any responces, as this is very
> important.. Thanks a million...
>
>BTW- Anyone who works/has worked for Atari, I could really use your help with i
>nfo on the old 2600, please email me if you are willing to help me.... thatnks
>alot!!
>
>-Peter

The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
game machine). The 2600 had some extra ASIC chips that were basically
modified graphics chips and PIA's for the joysticks. Later model 2600
might have incorporated many of the chips into one ASCI, as the weight
of the machines and part count decreased a lot over the years.

Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
their games. I have no idea how much RAM it had to work with, but I
would hazard a guess of 2 or 4K RAM. Think comes from a lot of hacking
with the 800 and 130xe computers. And occasionally hacking with the
2600 (fixing it for monitor composite video use, and audio hookups).
Also I tryed to make a cartridge-less system that stored the ROM into
a RAM cartridge that could be loaded up at some prior time (a way to
backup cartridges). I've heard of a setup like this where games could
be bought (cheaply) on FSK-recorded tapes, then you would load them
into a special RAM cartidge, and play them.

Anyways, if you're interested in looking for 2600 equipment, we've got
two 2600 machines around (one composite A/V modified), and lotsa
cartridges. Willing to sell for reasonable offer + shipping and
handling. Don't play it anymore, since going to computers + Nintendo
(interested in that too?).

Hope that helps your question... I might grab some 6502's out too,
since they must be fun to play with (as microcontrollers).
-shishin "squish" yamada
squish@endor.harvard.edu

Newsgroup: sci.electronics
Document_id: 53887
From: fishman@panix.com (Harvey Fishman)
Subject: Re: electronic parts in NYC?

There are also a couple or three places on West 45th between Fifth and
Sixth.  

Harvey


-- 
----------------------------------------------------------------------------
 Harvey Fishman   | 
fishman@panix.com | You don't get smart except by asking stupid questions.
  718-258-7276    |

Newsgroup: sci.electronics
Document_id: 53888
From: ketil@edb.tih.no (Ketil Albertsen,TIH)
Subject: Re: How to the disks copy protected.

In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:

>	I guess what I am saying is that your question is difficult, if not
>impossible, to answer.  What exactly do you want to know?  Do you need a good
>one for a project you are working on?  How secure must it be?  Are you trying
>to crack one that someone else has used?  I can probably make suggestions,
>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>legally, to tamper with copy protection.  It can also lead to corruption of
>files which you necessarily do not have back ups of (being as they are copy
>protected,) which can be devestating.)  Do you have absolutely no ideas for
>practical applications, and are merely curious?
>	Please clear up those questions, and I'll try to help as much as I
>can.

May we interpret this as an offer to volunteer as editor for a
"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
an initiative! *I* will volunteer to ask some of the questions, if you will
provide the answers :-)

Ketil Albertsen

Newsgroup: sci.electronics
Document_id: 53889
From: frode@dxcern.cern.ch (Frode Weierud)
Subject: Magstrip Card Reader Info


Can somebody please help me with information about an
American Magnetics Corporation Magstripe Card Reader that
I recently bought locally from a surplus dealer.

On the rear it has the following information:

	American Magnetics Corporation
	Carson, CA, USA
	Magstripe Card Reader
	Model 41,
	P/N 507500 - 2300112311

It is fitted with a cable with a RS232 Cannon 25-pin connector on
the end and has a separate power connector like the once used with
wall chargers.

Frode

**************************************************************************
*	Frode Weierud		Phone	:	41 22 7674794		 *
*	CERN, SL		Fax	:	41 22 7823676		 *
*	CH-1211 Geneva 	23	E-mail	:	frode@dxcern.cern.ch	 *
*	Switzerland			   or	weierud@cernvm.cern.ch	 *
**************************************************************************


Newsgroup: sci.electronics
Document_id: 53890
From: elr@trintex.uucp (Ed Ravin)
Subject: Re: electronic parts in NYC?

Taft Electronics, 45th Street between 5th & 6th -- the only one left in
what was once an entire district of electronics stores.  A little expensive.

Trans-Am Electronics, Canal Street near 7th Ave -- lots of surplus type
stuff.

Several other electronics or "surplus" type places are still on Canal
Street.

I think Bronx Wholesale Radio is still in business -- Fordham Road not
too far from Arthur Avenue in the Bronx.  Also in the Bronx is NorthEastern
(or was it Northwestern?  Northeast Electronics?) on Jerome Avenue near
Bedford Park Boulevard.  They're mostly a TV parts supply house, but when
I was building CB radio projects, they were quite handy..
-- 
Ed Ravin               | "A TV cop fires a gun three times an hour.  A real cop
Prodigy Services Co.   |  fires a gun only once every five years."
White Plains, NY 10601 |------------d i s c l a i m e r - w a s - h e r e -----
+1-914-993-4737        | elr@trintex.uucp or elr%trintex@uunet.uu.net

Newsgroup: sci.electronics
Document_id: 53891
From: wayne@uva386.schools.virginia.edu (Tony Wayne)
Subject: speaker impedance help needed

           I want to connect a very small "home-made" speaker
up to the headphone jack on my macintosh LC for an experiment.
The dc resistance of the speaker is 1 ohm.  Any ideas how I can
do this safely?  I think I need some kind of an impedance
transformer or something.?
-tony
 wayne@uva386.school.virginia.edu 

Newsgroup: sci.electronics
Document_id: 53892
From: cfb@fc.hp.com (Charlie Brett)
Subject: FET-TRONS(sp?)

Has anyone ever heard of FET-TRONS (or is it FETRONS, FETTRONS, ...).
These were FET replacement modules for vacuum tubes. I'm looking for
applications where they were used. 

       Charlie Brett - HP Ft. Collins

Newsgroup: sci.electronics
Document_id: 53893
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Los Angeles Freeway traffic reports

: While driving through the middle of nowhere, I picked up KNBR, AM 1070,
: a clear-channel station based in Los Angeles. They had an ad 
: claiming that they were able to get traffic flow information from 
: all of the thousands of traffic sensors that CalTrans has placed
: under the pavement. Does CalTrans sell this info? Does KNBR have
: an exclusive? What's the deal?

: ==Doug "Former L.A. commuter" Claar

You were right the second time, it is KNX. Believe it or not, I also
listen to KNX in the evenings here in Colorado! It's kind of fun driving
through the country listening to traffic jams on the 405. Back to your
original question. Yes, there are sensors just past every on-ramp and
off-ramp on the freeways. They're the same sensors used at most stoplights
now (coils in the pavement). You might want to give CalTrans a call or
even ask Bill Keene (KNX's traffic reporter). I doubt if just anyone can
get the information, but it would be worth asking just in case you can
get it.

      Charlie Brett (former LA commuter)  Ft. Collins, CO


Newsgroup: sci.electronics
Document_id: 53894
From: v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Radio Electronics Free information card


	How does the radio Electronics free information cards work.
Do they just send you some general information about the companies that
advertise in their magazine or does it also give you sign you up for a
catalog. 


                                  Neil Gandler

Newsgroup: sci.electronics
Document_id: 53895
From: bob@kc2wz.bubble.org (Bob Billson)
Subject: Re: subliminal message flashing on TV

kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan) says:
>Hi.  I was doing research on subliminal suggestion for a psychology
>paper, and I read that one researcher flashed hidden messages on the
>TV screen at 1/200ths of a second.  Is that possible?  I thought the

Take a look over in alt.folklore.urban.  There is a thread about subliminal
messages on TV.  The fact that subliminal messages don't work aside, an image
can't be flashed on a TV screen fast enough to not be noticed.
-- 
  Bob Billson, KC2WZ                          | internet: bob@kc2wz.bubble.org
  $nail:  21 Bates Way,  Westfield, NJ 07090  | uucp:     ...!uunet!kc2wz!bob

               "Friends don't let friends run DOS" -- Microware

Newsgroup: sci.electronics
Document_id: 53896
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Laser vs Bubblejet?

FYI:  The actual horizontal dot placement resoution of an HP
deskjet is 1/600th inch.  The electronics and dynamics of the ink
cartridge, however, limit you to generating dots at 300 per inch.
On almost any paper, the ink wicks more than 1/300th inch anyway.

The method of depositing and fusing toner of a laster printer
results in much less spread than ink drop technology.

It doesn't take much investigation to see that the mechanical and
electronic complement of a laser printer is more complex than
inexpensive ink jet printers.  Recall also that laser printers
offer a much higher throughput:  10 ppm for a laser versus about 1
ppm for an ink jet printer.

Something else to think about is the cost of consumables over the
life of the printer.  A 3000 page yield toner cartridge is about
$US 75-80 at discount while HP high capacity (~500-1000 page yield)
cartridges are about $US 22 at discount.  It could be that over the
life cycle of the printer that consumables for laser printers are
less than ink jet printers.  It is getting progressively closer
between the two technologies.  Laser printers are usually desinged
for higher duty cycles in pages per month and longer product
replacement cycles.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53897
From: ragee@vdoe386.vak12ed.edu (Randy Agee)
Subject: Radar detector DETECTORS?

Several years back one of the radar detectors manufacturers, in
defiance to Virginia's law against radar detectors, passed out
thousands of fake cardboard radar detectors at truck stops near
the Virginia State lines.  At that time there were no radar
detector Detectors!  I am not sure of the impact but I would
imagine that enforcement of the law by visually sighting a
radar detector became difficult - if not impossible!

As I said earlier, efforts to throw out or eliminate the VA law
against radar detectors has been in vain.  In fact, effective
Jan. 1, 1993, the fine for possession of a radar detector
accessable to the driver of a vehicle in VA is now $250.00.  

I have noted an interesting anomality with my Alinco DR-100 2
meter ham transceiver.... It will make a *cheap* radar detector
scream!  I am not sure of the range, but it is obvious by the
brake lights that it can be at least 50 feet at 50 watts! :-)

==============================================================================
Randy T. Agee - WB4BZX           | At some point, you probably pondered The 
P.O. Box 2120 - 20th floor       | Meaning of Life, and you came up with a 
Virginia Department of Education | satisfactory answer, which has or has not
Richmond, VA 23216-2120          | stood the test of time, or you shrugged
Phone (804) 225-2669             | mightily, muttered "Beats the heck out of
ragee@vdoe386.vak12ed.edu        | me," and ordered a cheeseburger.
=============================================================================
 

Newsgroup: sci.electronics
Document_id: 53898
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: How to the disks copy protected.

Write a good manual to go with the software.  The hassle of
photocopying the manual is offset by simplicity of purchasing
the package for only $15.  Also, consider offering an inexpensive
but attractive perc for registered users.  For instance, a coffee
mug.  You could produce and mail the incentive for a couple of
dollars, so consider pricing the product at $17.95.

You're lucky if only 20% of the instances of your program in use
are non-licensed users.

The best approach is to estimate your loss and accomodate that into
your price structure.  Sure it hurts legitimate users, but too bad.
Retailers have to charge off loss to shoplifters onto paying
customers; the software industry is the same.

Unless your product is exceptionally unique, using an ostensibly
copy-proof disk will just send your customers to the competetion.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 53899
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: 600RPM Floopy drives - UPDATE!

Many thanks to those who replied to my appeal for info on a drive I have
which is 3.5" 600RPM!!

I now have some information on how to modify this for use with a BBC B 
computer. Not only do you have to change the speed from 600 to 300 rpm
(tried that) but also change 8 components in the Rec/Play section to allow
for the lower data rate (250kbit, not 500kbit as it was designed for) and also
change the Recording Current to allow for the low data rate/rev speed!

Hopefully this should sort it all out .... not bad for 9 quid (normally 32 
quid and upwards ....)

The drive is a JVC MDP series drive ...

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
Document_id: 53900
From: einari@rhi.hi.is (Einar Indridason)
Subject: Re: How to the disks copy protected.

In <1993Apr21.085848.12704W@lumina.edb.tih.no> ketil@edb.tih.no (Ketil Albertsen,TIH) writes:

>May we interpret this as an offer to volunteer as editor for a
>"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>an initiative! *I* will volunteer to ask some of the questions, if you will
>provide the answers :-)


Ok, here could be the first question or answer or something:

Q: I want to copyprotect a program I wrote.  How should I do it?
A: You would be wise not to copyprotect that program.  You see, those 
   people that wants to get a cracked copy of your program will go to 
   various length to crack your program, and some of those crackers 
   are good, and know the common tricks.
   So, the copy protection wouldn't stop those.
   Ok, then.  What about legitimate users?  Copy protection can be a hassle
   for legitimate users, and can hinder them in their work, expecially
   if there is some "key" item that can get lost.
   So, the copy protection wouldn't help much of the legitimate users, but
   would make life somewhat of a misery for them.



(This is my opinion, and I speak as a legitimate user :-)
You are of course free to have your opinion about this subject....



--
einari@rhi.hi.is

Newsgroup: sci.electronics
Document_id: 53901
From: lgardi@uwovax.uwo.ca
Subject: Re: Long distance IR detection

In article <1993Apr20.183416.18744@dres.dnd.ca>, sburton@dres.dnd.ca (Stan Burton) writes:
> 
> --
> 
> I would like to be able to detect the angular position (low accuracy) of an
> IR emitting source at a distance of about 100 meters (more is better) in
> daylight.  The IR source could be emitting a signature; I'm leaning toward
> 30 KHz square wave with 50% duty cycle.
> 
> I am considering the use of a quadrant detector from Centronic Inc. to give
> information to a pan/tilt head to point the sensor and thus determine the
> angles.  For the source I am considering wazing the heck out of an IR LED(s),
> possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
> current pulses.  At this current the duty cycle of the LED drops to 10% and I
> would need to cycle five of them in turn to get the 50% required.
> 
> Has anyone done something like this?
>
Why don't you just run one LED at 60 KHz and use a flip flop at the receiving
end to divide by 2 and give you a good square 30KHz signal.
Just a thought.
LORI
 
> Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
> (403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6
-- 
<<<RED FISHY WINS>>>
Lori Gardi				(519) 661-2111 ext 8695
Dept. of Astronomy,			lgardi@uwovax.uwo.ca
University of Western Ontario
London, ON, CANADA, N6A 3K7

Newsgroup: sci.electronics
Document_id: 53902
From: leblanc@cvm.msu.edu (Pat Leblanc)
Subject: wireless data transfer

I am involved with a Michigan company that has an application requiring 
wireless data transfer.  If you have expertise or information that may 
assist us in this project, please contact me (INTERNET: leblanc@cvm.msu.
edu).


Newsgroup: sci.electronics
Document_id: 53903
From: hcb@netcom.com (H. C. Bowman)
Subject: 8x oversampling CD player


Hello--

I just bought a new portable CD player for the office, and I notice that
it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
I understand what oversampling is (the rate of discrete "samples"
exceeds the highest frequency component of interest by some factor),
I don't understand this "8 TIMES" business...  It seems to me that when
I bought my first CD player (was it REALLY 10 years ago?!), the specs
said "4 TIMES" ...  Could someone please tell me whether I'm getting
senile?  If I'm not, then what good does it do for the player to take
samples at a higher rate?  If I really wanted better fidelity, wouldn't
I have to have the same higher rate of sampling during the recording
process?  Furthermore, am I wrong in interpreting the sampling rate
(from the player's point of view) as being the same thing as the data
rate for the bit stream coming off the optical medium?  Does this mean
that the data rate (related to the rotational speed of the disk) has 
changed since 1983?

I'm so confused...  

--Cliff

-- 
| Clifford Bowman, Box 1890, Russellville, AR  72811 | hcb@netcom.com |
| I'm pretty sure the world *isn't* fair...  If it   | (501) 968-2232 |
| were, I'd be a lot worse off!                      |      N5TJU     |

Newsgroup: sci.electronics
Document_id: 53904
From: edhall@rand.org (Ed Hall)
Subject: Re: Los Angeles Freeway traffic reports

In article <C5uLqn.Gpw@fc.hp.com> cfb@fc.hp.com (Charlie Brett) writes:
>: While driving through the middle of nowhere, I picked up [KNX], AM 1070,
>: a clear-channel station based in Los Angeles. They had an ad 
>: claiming that they were able to get traffic flow information from 
>: all of the thousands of traffic sensors that CalTrans has placed
>: under the pavement. Does CalTrans sell this info? Does [KNX] have
>: an exclusive? What's the deal?

Well, they claim they are the only radio broadcaster with this
information.  But the city's cable channel (35 in CableVision areas)
shows this information map during travel times (6-9am and 4-7pm, I
believe).  Most of the major LA freeways are covered.  The
computer-generated map shows green, yellow, red, or flashing red
(respectively: <40mph, 25-40mph, >25mph, and "incident"--I might be off
a little on the speeds, since this is from memory).

I often look at this display in the morning to see if I really want to
fight the traffic on the Sepulveda Pass or work from home for a little
while to wait for it to clear.

Another poster explained the origin of the information: sensors (embedded
wire loops) in the pavement near ramps and every half mile or so.  CalTrans
has had a "big board" driven from this data in their traffic control center
for some time.  I don't know if they are selling the data or if anyone
with the equipment necessary for its transmission and display can have
it.

		-Ed Hall
		edhall@rand.org

Newsgroup: sci.electronics
Document_id: 53905
From: jimmy@fireflare (Jimmy Mosquera)
Subject: Re: help - how to construct home-built battery for 3rd grade sci report

In article <C5GE69.Lo0@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>Almost any two dissimilar metals in almost any electrically conductive
>liquid.
>
>Example: Copper and zinc in Coca-Cola...
>
>copper and galvanized steel nails in a lemon...
>
>Don't expect much power out, but it should be easily detectable
>with a voltmeter.
>
>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><



A copper and a zinc rod in a potato also work nice.



Newsgroup: sci.electronics
Document_id: 53906
From: martyj@mrcnext.cso.uiuc.edu (martin johnson)
Subject: Hi Volt from battery

I need a small battery powered hi voltage capacitive discharge supply to
deliver ~6 joules at 250 volts. This implies a 200uf cap. I have built
a very satisfactorily operating version from a MAX641, but do not like
the idea of using a $6 single source part. It seems that the ubiquitous
camera flash circuit is what I want, but I cant get mine apart without
breaking it. I would appreciate receiving the circuit description or
a source of one. I have already looked in several electronics circuits
handbooks to no avail. Thanx
--
______________________________________________
|  martin johnson      martyj@uiuc.edu       |
|  "mind your business", on first US coin    |
|____________________________________________|

Newsgroup: sci.electronics
Document_id: 53907
From: acm@Sun.COM (Andrew MacRae)
Subject: Re: arcade style buttons and joysticks

In article <1993Apr21.024036.7394@lynx.dac.northeastern.edu>, dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:
 > Hi there,
 > Can anyone tell me where it is possible to purchase controls found
 > on most arcade style games.  Many projects I am working on would
 > be greatly augmented if I could implement them.  Thanx in advance.


HAP controls just outside Chicago sells these.  I don't remember which
suburb they are in.  The prices are pretty reasonable and they are
easy to hook up.  I bought a new coin mechanism from them for $25.00
a couple of years ago.

						Andrew MacRae
						

Newsgroup: sci.electronics
Document_id: 53909
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>I built a little project using the radio shack 5vdc relays to switch
>audio.  I got pretty bad 'clicks' when the thing switched. 

>	Is there a good relay/relay circuit that I can use for switching
>audio, so that there will be *NO* noise of any kind on the audio lines.

	With relays alone, you will always get a transient when
you abruptly turn ON or OFF any channel.  If you don't want to hear
the transient, use some other device (a photoresistor-output optoisolator
is the usual sort of thing) to gently MUTE the signal, then switch,
THEN remove the power from the lamp in the optoisolator.

	It used to be standard practice to employ photoresistors
in switching audio, because the photoresistor time delay (a few
thousandths of a second) kept any noise in the digital side (which
drives the lamp) from contaminating the audio.  And, the devices
are cheaper than relays.

	John Whitmore

Newsgroup: sci.electronics
Document_id: 53910
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: Radar detector DETECTORS?

In article <1993Apr19.231050.2196@Rapnet.Sanders.Lockheed.Com> babb@rapnet.sanders.lockheed.com (Scott Babb) writes:
>Brian Day (bday@lambda.msfc.nasa.gov) wrote:
>: On December 29, 1992, it was illegal to operate a radar detector
>: in the state of Virginia.  If one got caught, one got fined $65.00.

>The Federal Communications Act of 1934 made it *legal* for you to
>operate a radio receiver of any kind, on any frequency (including
>X, K, and Ka bands) in the United States. 

	And the Commonwealth of Virginia has not exactly butted
against the issue on those grounds.  The claim is that AS A MATTER
OF TRAFFIC SAFETY one is not allowed to have a functioning radar
detector on the dashboard while operating a motor vehicle.

	Yes, the argument is bogus, BUT... it hasn't been successfully
challenged in court.  Yet.

	John Whitmore

Newsgroup: sci.electronics
Document_id: 53911
From: jbore@cosmos.shearson.com (Joe Bore)
Subject: Re: Need to find out number to a phone line



try finding a friend that has caller id, then give him a call...

jb


In article <20756.2bd16dea@ecs.umass.edu> alee@ecs.umass.edu writes:

   Path: shearson.com!uupsi!psinntp!uunet!haven.umd.edu!darwin.sura.net!newsserver.jvnc.net!howland.reston.ans.net!noc.near.net!nic.umass.edu!risky.ecs.umass.edu!umaecs!alee
   From: alee@ecs.umass.edu
   Newsgroups: sci.electronics
   Date: 18 Apr 93 15:04:10 GMT
   Lines: 13


   Greetings!

	   Situation:  I have a phone jack mounted on a wall.  I don't
		       know the number of the line.  And I don't want
		       to call up the operator to place a trace on it.

	   Question:   Is there a certain device out there that I can
		       use to find out the number to the line?
	   Thanks for any response.
						       Al


--
-------------------------------------------------------------------------------
Joe Bore					 | "Life is Short...Code Hard"
jbore@Shearson.COM | ...!uunet!shearson.com!jbore| 
(212)464-3431, Beeper:  (212)396-4248		 |

Newsgroup: sci.electronics
Document_id: 53912
Subject: Re: Power, signal surges in home...
From: emd@ham.almanac.bc.ca

vanderby@mprgate.mpr.ca (David Vanderbyl) writes:

> drand@spinner.osf.org (Douglas S. Rand) writes:
> 
> >   Hams can legally run up to 1500 watts.  It is very unlikely, however,
> >   that a ham would be running that kind of power from a car.
> >
> >Not possible either.  You'd need about a 300 amp alternator for
> >just the amplifier.
> 
> It is too possible.  As the original poster said "it is very unlikely"
> but definately possible.  (Can you say batteries?)


I've even seen pictures of an installation where the ham pulled a little 
trailer behind his car with a 4KW generator, and ran the full legal limit 
while mobile. I don't know what his gas mileage was like, though, or 
where he found resonators able to stand the gaff.


emd@ham.almanac.bc.ca (Robert Smits Ladysmith BC)

Newsgroup: sci.electronics
Document_id: 53913
From: tom@afthree.as.arizona.edu (Thomas J. Trebisky)
Subject: Re: A question about 120VAC outlet wiring..

crichmon@sedona.intel.com (Chris Richmond) writes:
>Well, my house was built just last year, and the breaker box is wired the
>same way.  All the white and ground wires are on a common bus.  Except for
>the 220V circuits, only black wires are hooked to the breakers.  It was
>the same way in the last two houses I had also.  Are you sure this is wrong?
>I still have the building inspector's signature on the breaker box.

The point is that the original poster was talking about connecting
ground and neutral in the *outlet* box (big NO NO), and you are talking
about them being connected in the breaker box (as things should be).

If this is not obvious, the point is that there should be current
flow in the white, i.e. neutral/return wires when things in the
house are operating.  There should not be any flow in the ground wires
unless there is a fault condition.  Notice also that in the breaker box
there is a wire leading from the above-mentioned junction to earth ground,
usually a pipe or spike driven into the ground.
-- 
	Tom Trebisky	ttrebisky@as.arizona.edu

Newsgroup: sci.electronics
Document_id: 53914
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: 8x oversampling CD player

In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>
>Hello--
>
>I just bought a new portable CD player for the office, and I notice that
>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>I understand what oversampling is (the rate of discrete "samples"
>exceeds the highest frequency component of interest by some factor),
>I don't understand this "8 TIMES" business...  It seems to me that when
>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>senile?  If I'm not, then what good does it do for the player to take
>samples at a higher rate?  If I really wanted better fidelity, wouldn't
>I have to have the same higher rate of sampling during the recording
>process?  Furthermore, am I wrong in interpreting the sampling rate
>(from the player's point of view) as being the same thing as the data
>rate for the bit stream coming off the optical medium?  Does this mean
>that the data rate (related to the rotational speed of the disk) has 
>changed since 1983?

[Note: I just tried to figure this stuff out about a month ago myself, from
various people on the net, so I could be wrong.]

The data is only ever read once (barring mistracks and such, of course),
and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
Oversampling takes two discrete data points, and interpolates n-1 points
between them for n times oversampling.  When I asked, people said that the
interpolation was not simply linear interpolation, but significantly more
complicated.

Anyway, then, the purpose of oversampling is to move the "effective"
sampling rate up to n times 44.1 KHz, in order to use higher frequency
antialiasing filters.  For the same quality filter, higher oversampling
lets you build cheaper filters, whereas for the same price filter, higher
oversamplings lets you build better filters.  So, assuming the quality of
all other components in a CD player remained the same, oversampling should
allow a manufacturer to produce _slightly_ better sound due to anti-alias
filtering.

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 53915
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Suggestions  on Audio relays ???

In article <1993Apr20.102756.1709@mala.bc.ca> wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
>In article <C5r60r.4ID@megatest.com>, alung@megatest.com (Aaron Lung) writes:
>> In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>>I built a little project using the radio shack 5vdc relays to switch
>>>audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
>>>My question is:
>>>	Is there a good relay/relay circuit that I can use for switching
>>>audio, so that there will be *NO* noise of any kind on the audio lines.
>> 
>> Are you switching high level signals or low level signals like pre-amp
>A novel circuit I used to build was a primitive "optical isolator".. It consists
>of a resistive photocell and a lamp, all packaged in a tube.  When the lamp is
>off the cell is high resistance.  Turn the lamp on and the resistance lowers

I use an H11F1   FET optoisolater to switch microphone level signals.
There is no click, since I put a .1uF cap across the LED.  Distortion
measurement are very low with mic level, and they went up to 0.03% at a
+ 14 dB line level.  All I did was put the FET in series with one leg
of the balanced line.  No hums, pops, just audio jumping out of silence.
The FET runs about 100 million ohms with the LED dark and drops to 150-200
ohms with it on.

Hey, it works, and works well.
Galen Watts, KF0YJ


Newsgroup: sci.electronics
Document_id: 53916
From: schaefer@imag.imag.fr (Arno Schaefer)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
|> 
|> >	I guess what I am saying is that your question is difficult, if not
|> >impossible, to answer.  What exactly do you want to know?  Do you need a good
|> >one for a project you are working on?  How secure must it be?  Are you trying
|> >to crack one that someone else has used?  I can probably make suggestions,
|> >assuming the activity is strictly legal.  (In general, it is a BAD idea,
|> >legally, to tamper with copy protection.  It can also lead to corruption of
|> >files which you necessarily do not have back ups of (being as they are copy
|> >protected,) which can be devestating.)  Do you have absolutely no ideas for
|> >practical applications, and are merely curious?
|> >	Please clear up those questions, and I'll try to help as much as I
|> >can.
|> 
|> May we interpret this as an offer to volunteer as editor for a
|> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
|> an initiative! *I* will volunteer to ask some of the questions, if you will
|> provide the answers :-)
|> 
|> Ketil Albertsen

Hey, now will you stop encouraging him? Copy protection only serves one pur-
pose: to keep the honest buyer from making (legal) backup copies. It will
definitely not stop any pirates. If you want to protect you soft, supply a
good documentation and support. This is IMHO the *only* way of effectively pro-
tecting software.

Best Regards,

Arno

-- 
--------------------------------------------------------------------------------
Arno Schaefer				ENSIMAG, 2e Annee
Email: schaefer@silene.imag.fr
Tel.: (33) 76 51 79 95			:-)
------- No, you're not paranoid - the world is really out to get you -----------

Newsgroup: sci.electronics
Document_id: 53917
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: arcade style buttons and joysticks

In article <1993Apr21.024036.7394@lynx.dac.northeastern.edu> dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:
>Subject: arcade style buttons and joysticks
>Can anyone tell me where it is possible to purchase controls found
>on most arcade style games.  Many projects I am working on would

What about the common joystick found in all computer shops?

- gerrit

Newsgroup: sci.electronics
Document_id: 53918
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Beginner's RF ???

In article <C5sr8H.JpH@cbnewsl.cb.att.com> klink@cbnewsl.cb.att.com (steven.r.klinkner) writes:
>Can anybody recommend a good, application-oriented beginner's reference
>to RF circuits?  
>Steve Klinkner                AT&T Bell Labs               srk@boeing.att.com

I have the ARRL Handbook for the Radio AMateur, and I'm getting the
Solid STate Design for the Radio Amateur.

The handbook is $25 and Solid State is $12 from ARRL, 225 Main, Newington,
CT 06111 but you should be able to find them at electronics or amateur radio
stores.
ARRL will want $5 or so for shipping.
Good Luck,
Galen Watts, KF0YJ



Newsgroup: sci.electronics
Document_id: 53919
From: henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley)
Subject: Re: 68HC16 public domain software?

In article <murashiea.15@mail.beckman.com>  writes:
> Does anyone know of an FTP site where I might find public
> domain software for the Motorola 68HC16 microprocessor?
> I am looking for a basic interpreter/compilier or a 'C'
> compiler.  Thanks in advance.
> 					Ed Murashie
Yep, at:
oak.oakland.edu
they have a couple different 68HC16 things in
/pub/msdos/emulators
and get the file
00-index.txt
for a list of what they have.
lige

Newsgroup: sci.electronics
Document_id: 53920
From: Daniel.J.Stern@dartmouth.edu (Daniel J. Stern)
Subject: Seeking info on wear on monitors 

We are Dartmouth engineering students.We are looking for documented
data regarding the wear associated with turning on an off a monitor and
how it relates to power consumption.  Interested in a comparison
between the wear on a monitor which is left on continuously and one
which is turned off when not in use.  

Please personalize E-mail to: ds@Dartmouth.edu

Thank you,

Dan Stern
Oliver Weir

Newsgroup: sci.electronics
Document_id: 53921
From: exuptr@exu.ericsson.se (Patrick Taylor, The Sounding Board)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.131908.29582@uhura.neoucom.edu> wtm@uhura.neoucom.edu (Bill Mayhew) writes:
>From: wtm@uhura.neoucom.edu (Bill Mayhew)
>Subject: Re: How to the disks copy protected.
>Date: Wed, 21 Apr 1993 13:19:08 GMT

>Write a good manual to go with the software.  The hassle of
>photocopying the manual is offset by simplicity of purchasing
>the package for only $15.  Also, consider offering an inexpensive
>but attractive perc for registered users.  For instance, a coffee
>mug.  You could produce and mail the incentive for a couple of
>dollars, so consider pricing the product at $17.95.

Or, _documentation_ for the program ;-).  A lot of shareware out there is 
very similar in the approach - send in your money, and you get 
documentation, and a free upgrade to the latest version.  Perhaps even 
support of some small degree.  Whatever you want to offer that is "better" 
than the circulating version.

>You're lucky if only 20% of the instances of your program in use
>are non-licensed users.

Figure about 50%, as I have seen.

>The best approach is to estimate your loss and accomodate that into
>your price structure.  Sure it hurts legitimate users, but too bad.

It doesn't really hurt legit users.  Shareware is still much cheaper than 
the alternatives.

 ----------------------------------------------------------------------------
 ---------Visit the SOUNDING BOARD BBS +1 214 596 2915, a Wildcat! BBS-------

 ObDis: All opinions are specifically disclaimed. No one is responsible.

    Patrick Taylor, Ericsson Network Systems  THX-1138
    exuptr@exu.ericsson.se                    "Don't let the .se fool you"

Newsgroup: sci.electronics
Document_id: 53922
From: henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley)
Subject: Re: what to do with old 256k SIMMs?

In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason  
Haines) writes:
> 
> 	I was wondering if people had any good uses for old
> 256k SIMMs.  I have a bunch of them for the Apple Mac
> and I know lots of other people do to.  I have tried to
> sell them but have gotten NO interest.
> 
> 	So, if you have an inovative use (or want to buy
> some SIMMs  8-) )
Sure I'll give you 10 bucks for all of them

Newsgroup: sci.electronics
Document_id: 53923
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: _Exhausted student needing HELP!

 
      Well, I've now been working on this DAMNED stepper controller board
 since 9pm.  It's now 6am... I'm pissed off.  Period.  Alright, I can
 drive the steppers through the 3479P's; no problem (that's with the
 6-wire steppers, 2 to +, and the other 4 are the phase lines).  Problem
 1:  I've got some 4 wire steppers.  I put the darkest line to + and the
 other 3 to the 3479P... worked, kinda.  Tried it with a printer stepper
 (moves the head back and forth, 4 wires), didn't work too well.  It 
would
 shift back and forth (use something like a 4017 instead?)  Also I've 
been
 trying to get a bunch of NPN's to work with it... NO LUCK... tried 
PNP's,
 still NO LUCK!!!  I don't know if I'm cursed on this or what, but I feel
 my brain slowly frying with the thought of STEPPER ... ARGGG!!!
         I don't know what's wrong with the transistor hook-up (to-220 
pkg
 type), also tryed the 2n2222-pkg type... no luck.

                         I'm going to try getting some z's, and I hope 
you
 can help me with this problem.
   If someone can please help me with this soon, it would be greatly
   appreciated...

                 Thanks.




 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 
l

Newsgroup: sci.electronics
Document_id: 53924
From: babb@sciences.sdsu.edu (J. Babb)
Subject: Re: Circuit Cellar Ink address?

In article <1qvlmaINNhuu@shelley.u.washington.edu>,
ptorre@hardy.u.washington.edu (Phil Torre) wrote:
> 
> Is CCI still published?  If so, does anyone have their address?


Circuit Cellar Inc.
4 Park St.  Suite 20
Vernon, CT  06066
(203)875-2751

Jeff Babb
babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
Programmer, SDSU - LARC

Newsgroup: sci.electronics
Document_id: 53925
From: klink@cbnewsl.cb.att.com (steven.r.klinkner)
Subject: Beginner's RF ???

Can anybody recommend a good, application-oriented beginner's reference
to RF circuits?  

I am pretty good on theory & know what different types of modulation mean, 
but don't have a lot of practical experience.  A book detailing working
circuits of different types (modulation, power, frequency, what is legal,
what is not, et cetera), would be very helpful.

Thanks.

-----------------------------------------------------------------------------
Steve Klinkner                AT&T Bell Labs               srk@boeing.att.com
                                                           att!boeing!srk    
-----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53926
From: jam@ameslab.gov (Jerry Musselman)
Subject: UART needed

I need to find a UART that will interface to an 8051 and do the following:
	-250k baud, 8 data bits, 2 stop bits, no parity
	-ability to do BREAK detect (IRQ or output pin)
	-IRQ on character received

I'm using a Dallas DS2250 at 16 Mhz (8051 clone), but it won't do 
break detect.  I've looked at the 6850, 8251, 7201, 2661, etc...

	Any help would be appriciated!!!

Newsgroup: sci.electronics
Document_id: 53927
From: rg@futserv.austin.ibm.com (R.G. Keen)
Subject: EICO tube tester repairs? 

I had the good luck to obtain an EICO dynamic conductance 
tube tester for a song. Unfortunately, I was a little out of
key; the only thing wrong with it was an open meter movement.
Does anyone know where I can find either another meter movement
like it, a dead-but-not-the-meter-dead unit, or schematics 
to specify the current scale of the meter movement? I can cut
and paste a more sensitive movement in if I can find what the
full scale current was. Or... is EICO still contactable?

The thing is a model 666 -nope, not a joke or any sort of snide
reference.

R.G.


Newsgroup: sci.electronics
Document_id: 53928
From: uli@izfm.uni-stuttgart.de (Uli Allgeier)
Subject: Re: PADS Question - How do I go from a schematic -> PCB?

Hi!
In article <C5svup.I4I@news.cso.uiuc.edu> rky57514@uxa.cso.uiuc.edu (Tall Cool One ) writes:

>After I have produced a schematic with PADS-LOGIC, how do I import it into 
>PADS-PCB to create a PCB pattern?  The only way I've gotten it to work is
>to output a FutureNet netlist, and then import this into PADS-PCB.  Is there
>another way of doing this?  I didn't see any information in the instructions
>provided, but I might have missed something.  Any suggestions would be 
>greatly appreciated.  Thanks!

Sorry, it's german, but I hope you understand it.


Uebertragung der Schaltplan-Daten (*.SCH) in die Board-Daten
(*.JOB):

PADS-LOGIC:
         In/Out
         Reports
         Net List
         Select      PADS-PCB
Net List Output file name
         -> filename angeben

PADS-PCB:
         In/Out
         Ascii In
Ascii input file name
         -> filename angeben
Errors aoutput file name
         -> filename angeben, nicht CR

Jetzt sind alle Bauteile auf einem Haufen und muessen mit Move
verteilt werden.

Viele Gruesse

Uli

Newsgroup: sci.electronics
Document_id: 53929
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In article <1993Apr19.185326.9830@Princeton.EDU> mg@cs.princeton.edu (Michael Golan) writes:
>The board itself is also identical, with room for all three caps. The
>US/Can versions is clearly indicated in both places.
>
>How does that make sense? 0.047/2 is 0.0235, essentially 0.022 for caps
>(there are just standard caps, no special W/type/precision). 

This may be a safety issue; the CSA is more paranoid in certain areas than
UL and such.  Two caps in series means that you don't have a short if one
of them shorts.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53931
From: camter28@astro.ocis.temple.edu (Carter Ames)
Subject: Lead Acid batteries & Concrete?


   I was just wondering one thing, actually two. ( I hope that this is the
proper place to post this subject)

  Why does a lead acid battery discharge and become dead (totally unuseable)
when stored on a concrete floor?  
  I decided to bring the battery in from the lawn mower and the motorcycle
from the unheated garage this year, *to preserve them* and I just
went to use them and noticed that not only do they not work, but 
they act like the two terminals are shorted.  I asked a friend
and he said that you should never do that, 'cause it ruins them,
but he couldn't tell me why.

thanks
camter28@astro.ocis.temple.edu

Newsgroup: sci.electronics
Document_id: 53932
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR remote control receiver

ab616@Freenet.carleton.ca (Marc Dion) writes:


>For a project of my own, I would like to build a Infra-Red Remote control
>receiver (for regular VCRs and TVs remotes).  Does anybody have any info
>or tips on how to build such receiver ?
>In particular,
>a) which photo detector should I use (which wavelength do remotes use) ?
>b) which ICs or circuit should I use ?
>c) any suggestions for circuit layout

>Please reply to this group (if you wish), but as well via e-mail (my
>link to usenet is not always available).

	I'd like to see this info as well.  As for wavelength, I think
you're primarily going to find two - 880 nM +/- a bit, and/or 950 nM
+/- a bit.  Usually it is about 10 nM either way.  The two most common
I have seen were 880 and 950 but I have also heard of 890 and 940.
I'm not sure that the 10 nM one way or another will make a great deal of
difference.

	Another suggestion - find a brand of TV that uses an IR remote,
and go look at the SAMS photofact for it.  You can often find some very
detailed schematics and parts list for not only the receiver but the
transmitter as well, including carrier freq. specs. and tone decoding
specs. if the system uses that.

Duane


Newsgroup: sci.electronics
Document_id: 53934
From: philc@macs.ee.mcgill.ca (Phil Crawley)
Subject: Read only if going to ISCAS93 in Chicago


   This is message is only of interest to those going to 
International Symposium on Circuits and Systems that is being
held in Chicago this May.
   
   I checking to see if there is any people out there who would be
interested in getting together for a pickup game of soccer during 
the off hours of the conference. If so could you e-mail me at:

philc@macs.ee.mcgill.ca

I'll bring a ball. If you know someone who is going to the 
conference and you know that they are avid soccer players
please pass on this message to them. Also if someone in
Chicago is going to the conference please let me know if
there is any field near the hotel where we can play.

Thanks. Bye.

Philip Crawley 

Newsgroup: sci.electronics
Document_id: 53935
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: HELP: MC146818A Real Time Clock Standby Mode

In article <1r0b69INN5ct@flash.pax.tpa.com.au> mgregory@flash.pax.tpa.com.au (Martin John Gregory) writes:
>I am having trouble obtaining the specified standby current drain from
>a MC146818A Real Time Clock...
>lowest current drain I can acheive at 3.7V Vcc is 150uA.  This is
>three times the specified MAXIMUM...
>1) Made sure that RESET/ is asserted for Trlh after powerup, and AS is
>   low during this time.
>2) Made sure that there is a cycle on AS after the negation of RD/ or
>   WR/ during which STBY/ was asserted...

Are any of the inputs to the chip coming from TTL?  Standby-drain specs
for CMOS chips typically apply only if inputs are pulled all the way down
to zero or all the way up to Vcc.  TTL isn't good at doing the former and
it won't do the latter at all without help from pullup resistors.  This
sort of thing can easily multiply power consumption by a considerable
factor, because the CMOS transistors that are supposed to be OFF aren't
all the way hard OFF.
-- 
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 53936
From: pyeatt@Texaco.com (Larry D. Pyeatt)
Subject: Membrane keypad with custom legend.

I had a catalog with membrane keypads, but I dunno what
happened to it, and it was so long ago that I forget the
name of the company.  Anyway, you could make your own
legend and slip it behind the bezel.  Really nice and 
reasonably priced.  Can anyone tell me where to get some
more of these critters?  I've tried several places, but
none of them seem to have keypads which allow you to use
your own legend.

Any suggestion would be appreciated.

-- 
Larry D. Pyeatt                 The views expressed here are not
Internet : pyeatt@texaco.com    those of my employer or of anyone
Voice    : (713) 975-4056       that I know of with the possible
                                exception of myself.

Newsgroup: sci.electronics
Document_id: 53937
From: dclaar@cup.hp.com (Doug Claar)
Subject: Los Angeles Freeway traffic reports


oops, that's KNX 1070. KNBR is up in 'Frisco, and down at 680.

==Doug "San Fran can't be 'the city': Jack Webb told me so" Claar

Newsgroup: sci.electronics
Document_id: 53938
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: Long distance IR detection

sburton@dres.dnd.ca (Stan Burton) writes:

>I would like to be able to detect the angular position (low accuracy) of an
>IR emitting source at a distance of about 100 meters (more is better) in
>daylight.  The IR source could be emitting a signature; I'm leaning toward
>30 KHz square wave with 50% duty cycle.

>I am considering the use of a quadrant detector from Centronic Inc. to give
>information to a pan/tilt head to point the sensor and thus determine the
>angles.  For the source I am considering wazing the heck out of an IR LED(s),
>possibly an Optek OP290 or Motorola MLED81.  Wazing would mean at least 1 Amp
>current pulses.  At this current the duty cycle of the LED drops to 10% and I
>would need to cycle five of them in turn to get the 50% required.

>Has anyone done something like this?


	Yeesh, you WILL be nailing those IRLEDs.  May I suggest getting your
mitts on the Siemens SFH484-2 IRLED?  This unit is designed to take some big
current pulses if you can get your duty cycle down a bit.  It will output
nearly a watt (975 mW) with REAL short duty cycle times.

(nice thing about the SFH484-2 is that it is CHEAP.  I got mine for about
50 cents a piece, even though I had to buy 100 of them....)

	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
6 WATTS.  I don't have the book here at work so I can't recall the company
name.  The 6 watter ain't cheap, around $108 but if you want some power,
mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
1 watt device in their line, and will sell small quan. to individuals.
If you are interested, I can find the book at home and get the
pertinent info.

	Now, as for the position detector, you might try ELTEC in Florida.
Phone number listed in the 92/93 ETID is 904-253-5328.  They seem like 
nice people.  Their specialty is passive infrared detection devices,
so they might be able to help you out.

	I'm curious about your applications if you don't mind saying.
The device sounds like it could be useful in a lasertag game, although you'd
need to up your carrier signal concept to 58.8 KHz......

Duane


Newsgroup: sci.electronics
Document_id: 53939
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Answers to many electronics Questions

I have notice a lot of electronics questions by people who are obviously not 
"tuned-in" to electronics.  Many of them have rather simple answers, and 
many of them require a circuit diagram.

Rather than muck up the network, why don't you write to me, send a self-
addressed, stamped envelop, and I'll answer your questions, if I can.

W. L. Willis, P. E.
114 Fern Circle
Clemson, SC 29631

Newsgroup: sci.electronics
Document_id: 53940
From: paula@nlbbs.com (Paula Stockholm)
Subject: Re: Need to find out number to a phone line

 In most areas of the country, serviced by ESS (or CESS), your phone
--

      * * * * * * * * * * * * * * * * * * * * * * * * * * *
      *               paula@nlbbs.com                     *
      *  Paula Stockholm            Cumberland, Maine USA *
      * * * * * * * * * * * * * * * * * * * * * * * * * * *

Newsgroup: sci.electronics
Document_id: 53941
From: kn1@cunixa.cc.columbia.edu (Kimball Ng)
Subject: Re: Laser vs Bubblejet?

kolstad@cae.wisc.edu (Joel Kolstad) writes:

>One other thing... there are bubblejets, and then there are BubbleJets.
>There are a few bubblejets out there that produce rather mediocre output
>(such as HP's dinky little BubbleJet), whereas most produce really good
>looking output (such as HP's DeskJets).  IBM and Canon both produce some of
>the really good style bubblejets.

>P.S. -- If you're in the market for a portable bubblejet printer, I can
>highly recommend the HP Portable DeskJet, although I've heard the portable
>Canons are good too (I needed PCL support, myself).  With the DeskJet
>Portable, you even get an undocumented PCMCIA card slot!

I second that suggestion.  Although I don't own the HP Portable Deskjet,
I *do* own the HP Deskjet 500.  It gives the nicest outputs, with only
a minor loss of quality.   For all intensive purposes (papers, letters,
resumes), I treat my Deskjet like a laser printer (You *do* have to
look a bit closely to see the blurs in the characters).  Only one
grudge, the ink that HP gives you does smudge rather quickly in the
presence of moisture (Even though the ink is waterproof).  However,
you would have to spend about $500 more for laser quality.

The cannon bubblejets are nice, however they don't seem to have as
much support (eg: drivers for popular programs) as the HP ink-jets.
Also HP Deskjet (regular,plus,500,500c) accepts xerox paper (I believe
that the cut-sheet feeder is an option for the cannon bubblejet).

If you don't mind refilling your printer with cheap ink (say
fountain-pen ink), then the HP deskjets are *very* cheap to maintain
(I paid $3.50 for my last bottle of ink and I expect it to last 9
months). 

	-Kimball (who doesn't work for HP, but just loves his printer
		  very much!)

PS: I have a question for you netters, I'm too afraid to refill with
the waterproof inks they sell in art-supply houses because I had brought
a bottle of waterproof ink and it clogged up my cartridge. I
wonder what is a 'good' waterproof ink (aside from buying refill-kits)
to refill my cartridge?





Newsgroup: sci.electronics
Document_id: 53942
From: paj@uk.co.gec-mrc (Paul Johnson)
Subject: Re: CAD Program for Electronics?

In article <1993Apr17.211126.23467@norfolk.vak12ed.edu> fculpepp@norfolk.vak12ed.edu (Fred W. Culpepper) writes:
>I am making a search for a CAD program that does a decent job
>of making schematic drawings.  The program needs to be in
>MS-DOS, Windows if possible.
>
>What I want the CAD program to do is to draw diagrams by
>dragging elements onto the screen, and in this the elements
>needed are as diverse as vacuum tubes to ICs (case with pins).
>It also needs to have provision for adding legends to the
>components as well as their values.  In other words I want to
>produce quality drawings.  Printout would be to either 24 pin
>dot-matrix and/or Laser Printer.

I would suggest Draw for Windows (by Micrografx).  I have this on my
home box.  Its quite impressive and only cost UKL100.  It has a rather
nice clip-art library facility which you can expand with your own
drawings.  There is no circuit component clip-art included, but you
could add your own quite easily.

It works with any Windows printer driver of course, and can also
export embedded postscript and PCX files.

Note: I am not connected with Micrografx in any way.

Paul.
-- 
Paul Johnson (paj@gec-mrc.co.uk).	    | Tel: +44 245 73331 ext 3245
--------------------------------------------+----------------------------------
These ideas and others like them can be had | GEC-Marconi Research is not
for $0.02 each from any reputable idealist. | responsible for my opinions

Newsgroup: sci.electronics
Document_id: 53943
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: help - how to constru

>Dean Anneser (anneser@pwa-b.uucp) wrote:
>: My 9 yr old son has signed up to do a science report on batteries.  I was
>: wondering if anyone could provide me with some information as to how to
>: construct a home-built battery.  In my grade school days, I remember seei
>: the 'ice cube tray' version, but I don't remember what to use as a good
>: electrolyte or what the easily obtainable metals were.
>:
>: Thank you in advance.

>I remember watching a whole "Mr. Wizzard" program on this subject when
>I was a kid.  The battery constructed on the program which made the
>biggest impression on me, and generated the most power, was made using
>a galvanized bucket (for the zinc) and a copper toilet tank float.  The
>electrolyte was sauerkraut!

Take a lemon.  Stick a copper strip into the lemon.  Stick a galvanized
nail in about 1 to 1-1/2 inches from the copper strip.  You should get
about 1/2 volt from it - enough to light an LED.


 * SLMR 2.1 * Support your medical examiner, die strangely.
                     
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
Document_id: 53944
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Food Dehydrators

>Does anybody out there have one of those food dehydrators I've been seeing
>all over late-night TV recently? I was wondering if they use forced air, hea
>or both. If there's heat involved, anybody know what temperature they run at
>My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
>and a heater. Seems to me you should be able to throw a dehydrator together
>for just a few bucks. Heck, the technology is only what? 1,000 years old?

You can learn how to build a deyhdrator very easily from the book, "The
Hungry Hiker's Guide to Good Food," by Gretchen McHugh.  The heat source
is a 100 watt light bulb.  Basically, it's a vertical wooden box with
ventilation holes in the top and bottom (lots of them, you want the air
to flow).  The light bulb goes in the bottom, and wire cake racks are
spaced every 6" starting about 10" above the bulb.

Or, at a slightly higher cost in electricity, you can do what I do:  Use
your oven.  (NOTE - I do this in an electric oven; some gas ovens may
not have a low enough setting).  Put food to be dried on cookie tins or
racks in the oven.  Set oven to 140 degrees (the lowest setting on my
oven - if yours goes down to 120 that's probably even better.)  Stick a
wooden spoon or something across the front corner of the oven and close
the door on the spoon so that it stays open about an inch - this allows
for airflow.  Leave the stuff in the oven for 6 to 8 hours; check it
often, since this dries it much faster than the dehydrator.  If you are
using cookie sheets instead of racks, turn the stuff over halfway
through.

If you want more info, e-mail me since this isn't really the right sub
for this stuff.

gerald.belton@ozonehole.com


 * SLMR 2.1 * I still miss my boss, but my aim is improving.
                       
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
Document_id: 53945
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: Need to find out numb

AL>>        Question:   Is there a certain device out there that I can
AL>>                    use to find out the number to the line?
AL>>        Thanks for any response.
AL>>                                                    Al

AL>There is a number you can call which will return a synthesized
AL>voice telling you the number of the line.  Unfortunately, for the
AL>life of me I can't remember what it is. The telephone technicians
AL>use it all the time.  We used to play around with this in our
AL>dorm rooms since there were multiple phone lines running between
AL>rooms.

It probably wouldn't help for you to post the number, since it appears
to be different in each area.  For what it's worth, in the New Orleans
area the number is 998-877-6655 (easy to remember, what?)


 * SLMR 2.1 * Ask me anything: if I don't know, I'll make up something.
                                          
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
Document_id: 53946
From: gerald.belton@ozonehole.com (Gerald Belton) 
Subject: MC SBI mixer

MJM>HI, I was wondering if anyone would be able to help me on twwo related
MJM>subjects. I am currently learning about AM/FM receivers and recieving
MJM>circuits. I understand a lot of things ,but a few things I am confused
MJM>abuot. The first is the MIXER, to mix the RF and local oscillator
MJM>frequencies to make the IF. Does anyone have any cicruit diagrams (as
MJM>simple as possible) for this kind of mixer? I have come across a
MJM>MC-SBL mixer chip But I have not been able to find it in any catalogs
MJM>(ACTIVE,etc...)

MJM>Along the same note, are there any SIMPLE fm receiver circuits anyone
MJM>may have stashed away somewhere and they couold let me see?.

MJM>P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
MJM>ELECTRICAL DIAGRAMS would help a lot.
MJM>I have seen a lot of theory books with no circuits and a lot of
MJM>circuit books with no theory, but one without the other does not help.

Digi-key has the NE-622 chip which has a local oscillator and mixer on
one chip.

For a great combination of theory with actual circuits, the best
reference for non-engineers is probably the Radio Amateur's Handbook
from the ARRL.  Most library's have it in the reference section.


 * SLMR 2.1 * If ignorance is bliss, why aren't there more happy folk?
 
----
The Ozone Hole BBS * A Private Bulletin Board Service * (504)891-3142
3 Full Service Nodes * USRobotics 16.8K bps * 10 Gigs * 100,000 Files
SKYDIVE New Orleans! * RIME Network Mail HUB * 500+ Usenet Newsgroups
Please route all questions or inquiries to:  postmaster@ozonehole.com

Newsgroup: sci.electronics
Document_id: 53947
From: wayne@uva386.schools.virginia.edu (Tony Wayne)
Subject: Pink Noise

What is Pink noise and how is it used in sound experiments?
-tony
 wayne@uva386.schools.virginia.edu


Newsgroup: sci.electronics
Document_id: 53948
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: how can 0.022 uF be different from two 0.047 in series?!

In article <C5uC68.19K@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>
>This may be a safety issue; the CSA is more paranoid in certain areas than
>UL and such.  Two caps in series means that you don't have a short if one
>of them shorts.

Not necessarily true; a short in one, if near the maximum series
voltage drop, will overvoltage the other one and short it too, more
-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
Document_id: 53949
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: Membrane keypad with custom legend.

In article <1993Apr21.125530.18387@texhrc.uucp> pyeatt@Texaco.com (Larry D. Pyeatt) writes:
>I had a catalog with membrane keypads, but I dunno what
>happened to it, and it was so long ago that I forget the
>name of the company.  Anyway, you could make your own
>legend and slip it behind the bezel.  Really nice and 
>reasonably priced.  Can anyone tell me where to get some
>more of these critters?

For some reason the name Grayhill springs to mind -- saw something
like that in a Grayhill catalog, along with options for custom printed
overlays and a neat little electroluuminescent backing that would make
the whole shebang glow a nice shade of green ..

mighty handy if you're trying to key a door combination in the dark
and don't want to TURN ON THE &%#$!! LIGHT ..

-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
Document_id: 53952
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Part MC68SEC811E2


I know what the 68HC811E2 is all about, but I'm trying to figure
out what the 68SEC811E2 is... specifically, what does the SEC
stand for?

----
Dale Ulan   VE6DAU     ulan@ee.ualberta.ca


Newsgroup: sci.electronics
Document_id: 53953
From: acooney@netcom.com (Alan Cooney)
Subject: Re: Los Angeles Freeway traffic reports

I live in the San Francisco Bay Area, and word has it that
something similar is on its way here.  Since we apparently
don't have the sensor base you folks have, they're installing
cameras at strategic points along the freeways (initial tests
are going to be in the Santa Clara area I'm told), with the
video being piped into a command center they're building
somewhere in the East Bay.  I'm not sure if frame grabbers or
cheap labor will be used to interpret the data, but large
multi-colored status displays will show the various routes
using different colors to represent the various average speeds
for each stretch of highway.  An announcer will sit in front
of the status 'wall', and will relay continuous verbal traffic
status to those who want to receive it.  They're apparently also
looking into licensing a low-AM frequency to be dedicated to
providing continuous audio from this system.

In the mean time, they'll set up large incandescent display
boards along the test stretch to provide commuters with data
on traffic conditions up ahead.  My understanding is that the
system is subsidized as a pilot program, and information from it
will be available free of charge.  Perhaps the LA system is
similarly free or provided at an obviously subsidized rate (read
"cheap").

We also have the traffic reports that are broadcast on the SAP
audio channel of television channels 2 and 36.  These are verbal
reports, qualified with a identification tone to tell in-vehicle
receivers like the 'Auto Talk' that the information coming next is
applicable to a given area.  In LA, they're probably using some
other TV channels, but the concept is the same.  Try setting your
stereo TV or VCR to receive the SAP audio channel, and go station
jumping to find out which one is broadcasting this information.
I believe this program is also subsidized, making the in-vehicle
receivers cheap to purchase (and without having to incur monthly
fees to use it).  Since the makers of these in-vehicle receivers
don't have to pay for the broadcast (this may not be completely
true), they likely have no investment in keeping the system
up and running when the Cal Trans stuff hits the airwaves.  You
may have a nifty little TV audio receiver in your car, nothing
more, when this happens.  Perhaps a word to the wise...?  ;)

I think we'd all be interested in a summary post if you get more
info on how the LA system is networked and paid for.

Cheers,
Alan
<acooney@netcom.com>


Newsgroup: sci.electronics
Document_id: 53954
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: Answers to many electronics Questions

Bill Willis (willisw@willisw.ENG.CLEMSON.edu) wrote:
: I have notice a lot of electronics questions by people who are obviously not 
: "tuned-in" to electronics.  Many of them have rather simple answers, and 
: many of them require a circuit diagram.

: Rather than muck up the network, why don't you write to me, send a self-
: addressed, stamped envelop, and I'll answer your questions, if I can.

: W. L. Willis, P. E.
: 114 Fern Circle
: Clemson, SC 29631

Because the network is quicker, easier, and free (at least to me).

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
Document_id: 53955
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: A question about 120VAC outlet wiring.

Dave Martindale (dave@imax.imax.com) wrote:
: They require two separate grounds.  One ground goes to the ground pin
: of the outlet, and the other ground wire is connected to the outlet's
: mounting tabs (and thus grounds the box and faceplate screw and metal
: faceplate, if any).

I thought the ground WAS connected to the metal frame on the socket.

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
Document_id: 53956
From: cmwolf@mtu.edu (Engineer by Day - Asleep by Night)
Subject: Re: Los Angeles Freeway traffic reports

Charlie Brett (cfb@fc.hp.com) wrote:
: You were right the second time, it is KNX. Believe it or not, I also
: listen to KNX in the evenings here in Colorado! It's kind of fun driving
: through the country listening to traffic jams on the 405. Back to your
: original question. Yes, there are sensors just past every on-ramp and
: off-ramp on the freeways. They're the same sensors used at most stoplights
: now (coils in the pavement). You might want to give CalTrans a call or
: even ask Bill Keene (KNX's traffic reporter). I doubt if just anyone can
: get the information, but it would be worth asking just in case you can
: get it.

I seem to remember that they sell the information (and a computer connection)
to anyone willing to pay.

On the subject of the pavement sensors, can anyone tell me more about them?

-- 
------------------------------------------------------------------------------
Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
------------------------------------------------------------------------------
         Remember, even if you win the Rat Race - You're still a rat.

Newsgroup: sci.electronics
Document_id: 53957
From: acollins@uclink.berkeley.edu (Andy Collins)
Subject: Voltage regulation and current limiting

One not-so-quick question to throw out there for you guys...

For our class project, we need to design and build a power supply
to the following specs:

Voltatge:  adjustable from 1-12V
Current:   *limited* at 1A

Voltage must stay within 2% of designated value for I from 0-1A
AC ripple less than 5 mV (rms)

Of course, we can't just use an adjustable voltage, current-limiting
regulator chip ;^)

Our problem is with the current limiting (i.e. we've found stuff to
do the rest of the parts of the circuit).  What the supply must do,
if presented with a load which would draw more than 1A, given the
supply voltage, is reduce the voltage so that the current will equal
one amp.  Thus, if we were to short the thing with the ammeter, we
should read one amp.  If we measure the current through a 1 ohm 
resistor at 12V, we should read one amp (and the output voltage, by
necessity, must be 1V.

The only basic idea we have seen for the current limiter involves
a circuit which will pull current off of the base of the output 
power transistor, and therefore reduce the output.

So, does anybody have any ideas we could work from?

Thanks in advance.

Andy Collins, KC6YEY
acollins@uclink.berkeley.edu

ps: If anybody wants to flame this as a stupid project, I agree fully,
    but I still have to do it, its graded ;^)


Newsgroup: sci.electronics
Document_id: 53958
From: acooney@netcom.com (Alan Cooney)
Subject: Re: Membrane keypad with custom legend.

Try the folks at Dimolex Corp., La Crescenta, CA 91214.
Their number is (818) 957-7001.  They make membrane keypads
that are very flat, in layouts from 2 to 128 keys.  They
have standard models, tactile models (with stainless domes
under each key to make a 'click' you can feel), as well as
backlit models.  Some of them can even be cut with scissors
to form a funky shape other than a rectangle.  Many of the
models are available in a 'kit' which includes a bezel,
colored and plain key covers, and rub on lettering to make
your own layout.  One piece prices aren't cheap, though,
as they want $10 for one four position pad *kit*, and $45
for a 40 position *kit*.

I have no affiliation with Dimolex or any company connected
with them.  I *have* purchased a couple of keypads from them,
and am pleased with what I got.

Cheers,
Alan
<acooney@netcom.com>


Newsgroup: sci.electronics
Document_id: 53959
From: DRAMALECKI@ELECTRICAL.watstar.uwaterloo.ca (David Malecki)
Subject: Re: Building a UV flashlight

In article <C5r6Lz.n25@panix.com> jhawk@panix.com (John Hawkinson) writes:
>My main question is the bulb: where can I get UV bulbs? Do they
>need a lot of power? etc., etc.

I've seen them in surplus stores.  All they are are fluorescent bulbs 
without the phosphor, and a UV transparent bulb (special glass).  I've
also seen incandescent versions that you screw into an ordinary 120VAC
socket, probably not what you want.

>
>I'm not too concerned with whether it's long-wave or short-wave
>(but hey, if anyone has a cheap source of bulbs, I'll take both).
>
>One other thing: a friend of mine mentioned something about near-UV
>light being cheaper to get at than actual UV light. Does anyone
>know what he was referring to?

As far as I know, near UV (as opposed to far-UV) is longwave UV (near
the visible spectrum).  Longwave UV is safer as far as accidental (I hope)
exposure to the eyes.  As far as fluorescent minerals go (the reason a
friend has a UV lamp), some only respond to only one of short or long UV.

Hope this helps.

Dave.



>
>Thanks much.
>
>
>--
>John Hawkinson
>jhawk@panix.com
 ---------------------------------------------------------------------- 
| Who I am:  David Malecki                                             |
| Who you think I am:  dramalecki@electrical.watstar.uwaterloo.ca      |
|                                                                      |
 ----------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 53960
From: karplus@cse.ucsc.edu (Kevin Karplus)
Subject: Re: decoupling caps - onboard


I've used on-chip capacitors to reduce ground-bounce noise on a small
systolic array chip that had 50pF loads on the clock lines.
(Design was in 2-micron n-well cmos, using the MOSIS scalable design rules.)
Here are some thoughts on the bypass capacitors:

1) They don't help much with simultaneous output switching--there is
	still a large inductance between the bypass capacitor and the
	load capacitor (on both the signal line and the ground
	return), so you still get ground and power line bounce. 

2) They do help a lot with on-chip loads, as I had with the high load
	on the clock lines. 

3) The transients you are trying to suppress are really high
	frequency, so forget about large areas of poly-thin-oxide-diff
	capacitors, since the RC time constant is too large.
	What I did is to make a metal2, metal, poly, diff sandwich,
	but put a lot of holes in the poly layer, allowing frequent
	diff-metal1 contacts.  I forget exactly how wide the poly
	lines were.  If I were doing this design again, I'd probably
	omit the diff altogether, and use a solid poly sheet instead,
	using just m2, m1, and poly (and substrate, but that has such a high
	resistance it can be ignored at these speeds).

4) You are probably better off trying to tune your circuit to run with
	slightly slower edges and lower voltage swings (especially for
	output signalling), than spending chip area on capacitors.
	I had spare space on the die since the circuit was too big for
	a MOSIS tiny chip, and the next size up was twice as big as I
	needed. 

Kevin Karplus
-- 
Kevin Karplus		karplus@ce.ucsc.edu

Due to budgetary constraints the light at the end of the tunnel is
being turned off.

Newsgroup: sci.electronics
Document_id: 53961
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Anyone got 200+ Schadow switches with LED?

Name your price, cap colours & quantity available.
cheers
Mike

Newsgroup: sci.electronics
Document_id: 53963
From: mycal@NetAcsys.com (Mycal)
Subject: Need to find out number to a phone line 


try comp.dcom -  I was reading a thread a while back about an 800 number
that you could dial.  worked here.  It was a sales line for sprint I think
telling you that you could have all your customers numbers using there
ANI, then it told you your number.  Should work with any modern switch.

mycal


---------------------------------------------------------------------------
PGP key on request.       mycal@netacsys.com
                                                              \ //
Mycal's way of skiing moguls:                                 // \
turn, turn, turn, air, survive, survive, survive...     No Risk, No Rush

Newsgroup: sci.electronics
Document_id: 53964
From: mycal@NetAcsys.com (Mycal)
Subject: ATARI 2600 Processors 


For all people that are interested in every aspect of the 2600 try the
zine:

2600 connection
$1 cash to :
Timothy Duarte
PO Box N, 664
Westport, MA 02790

for sample



---------------------------------------------------------------------------
PGP key on request.       mycal@netacsys.com
                                                              \ //
Mycal's way of skiing moguls:                                 // \
turn, turn, turn, air, survive, survive, survive...     No Risk, No Rush

Newsgroup: sci.electronics
Document_id: 53965
From: rubin@cis.ohio-state.edu (Daniel J Rubin)
Subject: Re: arcade style buttons and joysticks

> Hi there,
> Can anyone tell me where it is possible to purchase controls found
> on most arcade style games.  Many projects I am working on would
> be greatly augmented if I could implement them.  Thanx in advance.

Try Parts Express in Dayton, Ohio also.  They have a complete line of 
professional arcade buttons, joysticks etc...

The have a 1-800 number so call 1-800-555-1212 and ask them what the 1-800
number for Part Express in Dayton, Ohio is.  I love the free 1-800 directory 
assistance...

                                                               - Dan
-- 
             Daniel Joseph Rubin     rubin@cis.ohio-state.edu 
     
                       GO BENGALS!      GO BUCKS!

Newsgroup: sci.electronics
Document_id: 53966
From: alan@apple.com (Alan Mimms)
Subject: Re: UART needed (really BREAK detect)

In article <jam.19.735404158@ameslab.gov>, jam@ameslab.gov (Jerry
Musselman) wrote:
> 
> I need to find a UART that will interface to an 8051 and do the following:
> 	-250k baud, 8 data bits, 2 stop bits, no parity
> 	-ability to do BREAK detect (IRQ or output pin)
> 	-IRQ on character received
> 
> I'm using a Dallas DS2250 at 16 Mhz (8051 clone), but it won't do 
> break detect.  I've looked at the 6850, 8251, 7201, 2661, etc...
> 
> 	Any help would be appriciated!!!

Actually detecting a BREAK is done by watching for a "character" containing
all zero bits with the framing error resulting from its receipt.  This
means that the line stayed in the zero bit state even past the stop bit
time slot, which basically indicates a BREAK.  There is no special way to
detect BREAK that I have found other than this -- there's no magic signal
generated by UARTs, etc.

Alan Mimms (alan@apple.com, ...!apple!alan)   | My opinions are generally
Portable Macintosh Software Group             | pretty worthless, but
Apple Computer                                | they *are* my own...
Art without engineering is dreaming.  Engineering without art is
calculating.
	-- Steven K. Roberts in "Computing Across America"

Newsgroup: sci.electronics
Document_id: 53967
From: mb4008@cehp11 (Morgan J Bullard)
Subject: Re: Uninterruptible Power Supply

alung@megatest.com (Aaron Lung) writes:

>In article <1qk724INN474@hp-col.col.hp.com> cab@col.hp.com (Chris Best) writes:
>>I'm no expert at UPS's, but you said something that made it sound like
>>you didn't realize something.  On a typical UPS (well, on ours, anyway),
>>there is NO switchover from AC to DC.  All the protected equipment is
>>ALWAYS running from the batteries (via an inverter), with the usual 
>>condition of also having them on charge.  If the power fails, big deal - 
>>the computers never see it (until the batteries start to droop, but 
>>there's something like 60 car-sized batteries in that cabinet, so it 
>>takes a while).
>>
>>If you were gonna run the guts on straight DC instead of an inverter,
>>why not do it all the time?  Then there'd be no switchover to screw
>>things up, and no having to sense the failure fast.  Just keep the DC
>>on charge when the power is on, and it'll be there in zero time when
>>you "need" it.
>>

>Actually, it's a bit more complicated than that...I sounds to me,
>your UPS takes in AC, rectifies it to DC to charge the batteries, and
>then takes the battery DC and chops it to AC again, feeding your
>equipment.  This approach is the easiest and cleanest way to
>switchover from the mains to battery once your power kicks out since,
>as you mentioned, nothing will know about what happened down the line.

>Another way to do the UPS scheme is to use the mains until you
>lose power, and then kick in the battery backup with it's inverter to
>replace the lost power.  The problem here is the switchover time and
>you've got to resync the AC in no time flat.
That's a standby unit not a UPS, otherwise there would be no interuption.
Many standby units are labled as UPS's though.  
 			Morgan Bullard mb4008@coewl.cen.uiuc.edu
				   or  mjbb@uxa.cso.uiuc.edu


>Unfortunately, most everything is built around the assumption that
>AC is available, so the UPS guys have to provide and AC output to
>be usable...ya sorta have to make it work with what there already.

>Similar story with our telephone system.  It was first invented back
>in the 1800's.  We're still using the same damn system (media) as they
>did back then.  If I have a phone from back then, I can assure you
>it'll work on today's phone system.  It costs too much to overhaul
>everyone to a new system, so they make it work with what is out there.

>.

Newsgroup: sci.electronics
Document_id: 53968
From: ritterbus001@wcsub.ctstateu.edu
Subject: Re: IR remote control receiver

In article <wb9omc.735429954@dynamo.ecn.purdue.edu>, wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes:
> ab616@Freenet.carleton.ca (Marc Dion) writes:
> 
> 
>>For a project of my own, I would like to build a Infra-Red Remote control
>>receiver (for regular VCRs and TVs remotes).  Does anybody have any info
>>or tips on how to build such receiver ?
>>In particular,
>>a) which photo detector should I use (which wavelength do remotes use) ?
>>b) which ICs or circuit should I use ?
>>c) any suggestions for circuit layout
> 
> 	Another suggestion - find a brand of TV that uses an IR remote,
> and go look at the SAMS photofact for it.  You can often find some very
> detailed schematics and parts list for not only the receiver but the
> transmitter as well, including carrier freq. specs. and tone decoding
> specs. if the system uses that.
> 
Probably won't help.  I'd be willing to bet that _every_ manufacturer
used those little self-contained modules.  I think Sharp made them.
Radio Shack used to sell them for a few bucks (maybe they still do.)

The module had 3 leads:  power, ground and demodulated output.  It
contained the photo-detector, amplifier, integrator and demodulator
all in a tiny metal can.

If you want to buy one, try Radio Shack, or else a TV repair shop can
probably order one.  BTW - the carrier frequency is 40 KHz, and each
different TV/VCR/cable box/stereo manufacturer uses a unique pulse
scheme to perform each different function on their equipment.


Jim Ritterbusch
ritterbus001@wcsu.ctstateu.edu    - or - ne22@radiomail.net  (temp, rf)
There is an art, the Guide says, or rather a knack to flying.  The
knack lies in learning how to throw yourself at the ground and miss.


Newsgroup: sci.electronics
Document_id: 53969
From: craw@yoyo.cc.monash.edu.au (Sebastian Filzek)
Subject: IR detector 'cards'???

Hi people..

OK heres my problem.... 
I keep hearing about these little credit card type of things which
detect IR light....

I believe that you have to 'charge them up' under normal (visible) light
and then if they are exposed to IR light they glow or something like
that...

I think that they are avaliable in the states and even in England, but
alas I live in Australia.  Could someone please inform me if I can get
these things over here, and if so where??? and how much???

Also are they really commonly avaliable in the states, and if so, then
how much are they and who sells them (maybe if I cant get one here, I'll
write to one of the companies over seas..)

Anyway.... Thanks in advance...

Sab
93


Newsgroup: sci.electronics
Document_id: 53970
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: Re: Suggestions  on Audio relays ???

>In article <C5qsBF.IEK@ms.uky.edu> billq@ms.uky.edu (Billy Quinn) writes:
>>I built a little project using the radio shack 5vdc relays to switch
>>audio.  I got pretty bad 'clicks' when the thing switched. 
>
>>	Is there a good relay/relay circuit that I can use for switching
>>audio, so that there will be *NO* noise of any kind on the audio lines.
>
I missed the first part of this thread; are you switching line level or
speaker level audio?
If line level, there's a single chip 4x1 *stereo* audio switch available
that switches 4 two-channel inputs into 1 two-channel output, and also
has a mute function, all controllable with ttl inputs.  LM1037, I think?

If speaker level, never mind.  :(

Phil Torre (ptorre@u.washington.edu)



Newsgroup: sci.electronics
Document_id: 53971
From: franko@cco.caltech.edu (Frank Filipanits)
Subject: Re: arcade style buttons and joysticks

> > Can anyone tell me where it is possible to purchase controls found
> > on most arcade style games.  Many projects I am working on would
> > be greatly augmented if I could implement them.  Thanx in advance.

>HAP controls just outside Chicago sells these.
>						Andrew MacRae

Actually, it's HAPP, and some of their equipment can be found in the 
Parts Express catalog (1-800-338-0531).  They show switches for $2,
joysticks for $13 and trackballs for $80.  They also have pinball parts.

Good luck.


-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Frank Filipanits Jr.    B.S. EE/Music, California Institute of Technology '92
Audio Consultant          M.S. Music Engineering, University of Miami     '94
franko@alumni.caltech.edu   "No, officer, I don't know how fast I was going."

Newsgroup: sci.electronics
Document_id: 53972
From: mcmahan@netcom.com (Dave Mc Mahan)
Subject: Re: 8x oversampling CD player

 In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>
>>I just bought a new portable CD player for the office, and I notice that
>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>>I understand what oversampling is (the rate of discrete "samples"
>>exceeds the highest frequency component of interest by some factor),
>>I don't understand this "8 TIMES" business...  It seems to me that when
>>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>>senile?  If I'm not, then what good does it do for the player to take
>>samples at a higher rate?  

>The data is only ever read once (barring mistracks and such, of course),
>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>Oversampling takes two discrete data points, and interpolates n-1 points
>between them for n times oversampling.  When I asked, people said that the
>interpolation was not simply linear interpolation, but significantly more
>complicated.

You are quite correct in your understanding.  The filtering is not
interpolation, as that would distort the frequency content of the signal
you are listening to.  Generally, these players run the samples thru an
all-pass filter network.  I have done this for ECG waveforms from a person's
heart, and the effect is rather spooky.  It actually reconstructs peaks
that weren't there (correctly, too!) and fills in the gaps with the
properly computed values, just as if there had been a real sample taken at
that point.  I use a CPU to do all the math.  It takes a decent (but not
unreasonable) amount of CPU time to do this.  You can keep up with things
in realtime if you write efficient code.

In case you care, the filtering method uses an FIR (finite impulse response)
filter.  I'd guess that CD makers use the same kind of method.  Anybody out
there know the real answer?  I'd say that they use a tapped delay line with
resistor/op-amp weighting to accomplish the filtering.  This strikes me as
the most cost effective method for volume production runs.


>Anyway, then, the purpose of oversampling is to move the "effective"
>sampling rate up to n times 44.1 KHz, in order to use higher frequency
>antialiasing filters.  For the same quality filter, higher oversampling
>lets you build cheaper filters, whereas for the same price filter, higher
>oversamplings lets you build better filters.  So, assuming the quality of
>all other components in a CD player remained the same, oversampling should
>allow a manufacturer to produce _slightly_ better sound due to anti-alias
>filtering.

Actually, I think the only reason they do this is so that they can say that
they have a marketting gimic.  I would guess that it is acutally cheaper to
filter an oversampled signal than not.  You can use sloppier components and
give the filter a roll-off that isn't so sharp.   It's too bad that they
charge more for something that (I think) is actually less costly to build.

I seriously doubt that the filters cost the same but are better.  They are
built to a price spec, and that spec says "cheap as possible!". 


>					---Joel Kolstad

  -dave
-- 
Dave McMahan                            mcmahan@netcom.com
                                        37N 17.382    121W 59.190 

Newsgroup: sci.electronics
Document_id: 53973
From: rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter)
Subject: Can Radio Freq. Be Used To Measure Distance?

I'm wondering if it's possible to use radio waves to measure the
distance between a transmitter(s) and receiver?

Seems to me that you should be able to measure the signal strength
and determine distance. This would be for short distances (2000 ft),
and I would need to have accuracy of 6 inches, or so.

How about measuring vertical distance as well, any chance - or am I getting
ridiculous?

What frequencies would be best for this? Or does matter?

Sorry if I'm "mucking up" the network with one of those questions best
answered by Bill Willis via US Mail... and I apologize for not being
"tuned-in" to electronics. :-)


R.G. Carpenter, Ph.D., P.E. (sorry... only an ME)


Newsgroup: sci.electronics
Document_id: 53974
From: pauls@trsvax.tandy.com
Subject: Re: Need source for old Radio Shack ste


 It's made by Rohm. (as is all BAxxx parts). Call 714-855-2131 and ask if
 you can get a sample (it's only like a $2 part).



Newsgroup: sci.electronics
Document_id: 53975
From: pauls@trsvax.tandy.com
Subject: Re: Need Info on DSP project


Motorola has a good app note on a 10 band equalizer using a 56000 DSP. It
could be easily ported to an Ariel board, or even a Turtle Beach 56K
development system.



Newsgroup: sci.electronics
Document_id: 53976
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <C5v13M.C37@bcstec.ca.boeing.com> rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>I'm wondering if it's possible to use radio waves to measure the
>distance between a transmitter(s) and receiver?

Yes, you could.

>Seems to me that you should be able to measure the signal strength
>and determine distance. This would be for short distances (2000 ft),
>and I would need to have accuracy of 6 inches, or so.

Well, letsee (whipping out HP-48SX, soon to be GX): 6 inches/3*10^8 m/s=.5
nanoseconds resolution.  Hmm.  That'll be rather difficult!

The more standard (read: better) method is to use ultrasound, generally
somewhere around 40kHz.  Sound travels a heck of a lot slower than light
(radio waves), and is therefore much easier to deal with.

>What frequencies would be best for this? Or does matter?

It might be easiest to visit a hardware store and look at the numerous
"sonic estimator" type devices that do what you want here.  Many are pretty 
cheap too -- <$30.  (In fact, for awhile the Stanley Estimator was selling
for something like $8.  That's the one I bought! :-) )

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 53977
From: system@garlic.sbs.com (Anthony S. Pelliccio)
Subject: Re: Beginner's RF ???

klink@cbnewsl.cb.att.com (steven.r.klinkner) writes:

> Can anybody recommend a good, application-oriented beginner's reference
> to RF circuits?  
> 
> I am pretty good on theory & know what different types of modulation mean, 
> but don't have a lot of practical experience.  A book detailing working
> circuits of different types (modulation, power, frequency, what is legal,
> what is not, et cetera), would be very helpful.
> 
> Thanks.

Well, you might try the A.R.R.L.'s license study guides. For example, my
Advanced Class study guide has lots and lots of good RF and electronics
theory in it. I would imagine the other books are good too.

Tony

-----------------------------------------------------------------------
-- Anthony S. Pelliccio, kd1nr/ae    // Yes, you read it right, the  //
-- system @ garlic.sbs.com          // man who went from No-Code    //
-----------------------------------// (Thhhppptt!) to Extra in     //
-- Flame Retardent Sysadmin       // exactly one year!            //
-------------------------------------------------------------------
-- This is a calm .sig! --
--------------------------


Newsgroup: sci.electronics
Document_id: 53978
From: system@garlic.sbs.com (Anthony S. Pelliccio)
Subject: Re: arcade style buttons and joysticks

dnewman@lynx.dac.northeastern.edu (David F. Newman) writes:

> Hi there,
> Can anyone tell me where it is possible to purchase controls found
> on most arcade style games.  Many projects I am working on would
> be greatly augmented if I could implement them.  Thanx in advance.
> 
> -Dave
> dnewman@lynx.dac.northeastern.edu
> 

Contact Chris Arthur at Chris_Arthur@pennies.stratus.com
He restores lots of old video and arcade games and knows where to get
parts.

Tony

-----------------------------------------------------------------------
-- Anthony S. Pelliccio, kd1nr/ae    // Yes, you read it right, the  //
-- system @ garlic.sbs.com          // man who went from No-Code    //
-----------------------------------// (Thhhppptt!) to Extra in     //
-- Flame Retardent Sysadmin       // exactly one year!            //
-------------------------------------------------------------------
-- This is a calm .sig! --
--------------------------


Newsgroup: sci.electronics
Document_id: 53979
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <wb9omc.735430855@dynamo.ecn.purdue.edu>, wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes...

>	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
>6 WATTS.  I don't have the book here at work so I can't recall the company
>name.  The 6 watter ain't cheap, around $108 but if you want some power,
>mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
>1 watt device in their line, and will sell small quan. to individuals.
>If you are interested, I can find the book at home and get the
>pertinent info.
> 

You are probably referring to the products of
		
		Opto Diode Corp.
		750 Mitchell Road
		Newbury Park Ca 91320
		805 499-0335

The make some amazing IRLED's.  The really high-powered devices are arrays of
3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
designed as illuminators for IR vision systems.

I would also be interested in the application here.  I work with a Dance and
Technology program, and want to build something to track dancers on a 30 foot
wide stage from 50 feet away.

Newsgroup: sci.electronics
Document_id: 53980
From: mcovingt@aisun1.ai.uga.edu (Michael Covington)
Subject: Re: Radar detector DETECTORS?

There is or was a microwave tower next to Florida's Turnpike, and you
could watch the cars hit the breaks as they came in sight of it every
morning...

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 53981
From: schaerer@isi.ethz.ch (Thomas Schaerer)
Subject: Re: Voltage regulation and current limiting

Andy Collins (acollins@uclink.berkeley.edu) wrote:
: One not-so-quick question to throw out there for you guys...

: For our class project, we need to design and build a power supply
: to the following specs:

: Voltatge:  adjustable from 1-12V
: Current:   *limited* at 1A

: Voltage must stay within 2% of designated value for I from 0-1A
: AC ripple less than 5 mV (rms)

To decide which kind of circuit you must know the initialprecission of
the limiter-current and the allowed temp-drift.

In the first case, you can use a Ube of a transistor as a voltage-reference
of about 0.7 VDC with a temp-drift of 2mV/K. In the second case its better
you use a bandgap-ref and a opamp-circuit to detect the maximum-current.
The output of this opamp controlls the outputstage to limit the current.

Bye Thomas

Newsgroup: sci.electronics
Document_id: 53982
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Fujitsu 8" HDD

In article <1993Apr17.204351.2256@aber.ac.uk> cjp1@aber.ac.uk (Christopher John Powell) writes:

[deletions]

>It appears to use two balanced-line connections, but what each connection
>corresponds to I know not. One connection is a 30-way IDC, the other a
>60-way IDC.

Sounds like it is an SMD interface to me, not being at work now
to actually count pins.  there are two varients, SMD  and
SMDC (I think), only minor differences between them.  Widely used
prior to the advent of SCSI for large drives (or all drives) on minis
(and mainframes(?) no experience on those).

Richard Dell

Newsgroup: sci.electronics
Document_id: 53983
From: gregpen@crash.cts.com (Greg Penetrante)
Subject: Re: Adcom cheap products?

In <1qmbi7$aln@transfer.stratus.com> Michael_LaBella@vos.stratus.com writes:

>I gather by off-shore assembly you mean that adcoms are built by 
>blue-fin tuna's who are into that squid-fi sound?  (I agree on that one). 
>My Adcom 555 preamp did sound better after installing the famous  
>"running the chips class "A" resistor mod", and replacing the metal 
>bottom cover with plexiglass,, too bad the factory could not make em sound 
>better,, but better sound, unfortunately, does not appear to be a priority 
>with Adcom, else the mods would neither have been necessary, nor would they 
>have improved what was already touted as superlative state-o-d-art le'sound. 
>I really want to hear from all those people out there who have traded up  
>from an sp9II (even an sp3a!) to a GFP-555/etc., or maybe from those that 
>have dumped their forte' amps for a GFA-555/etc....  



I am one of those folks who traded UP from a 500 to an Audio Research SP9 II!

:-)

Am I enjoying it? Yes!  The SP9 DOES sound better... but at a price.
-greg


Newsgroup: sci.electronics
Document_id: 53984
From: plumpe@oasys.dt.navy.mil (David Plumpe)
Subject: Re: Pink Noise

In sci.electronics, wayne@uva386.schools.virginia.edu (Tony Wayne) writes:
>What is Pink noise and how is it used in sound experiments?

    Pink noise has constant power per geometric frequency increment
(octave, 1/3 octave, etc).  Thus the 10kHz-20kHz octave has the same
amount of noise power as the 10Hz-20Hz octave.
    White noise has constant power per arithmetic frequency increment
(Hz, kHz, etc).  Thus the 10kHz-10.1kHz band has the same amount of
noise power as the 10Hz-110Hz band (both bands are 100Hz wide).
    Pink noise can be made by passing white noise thru a -3db/octave
filter (usually approximated by a network of several RC pairs).
Note: you can't get -3db/octave by using half a -6db/octave network 
:-(
    Pink noise is commonly used in audio power response measurements.
It shows up on audio spectrum analyzers (with octave-related bands)
as a flat line across the bands.

DaveP

Newsgroup: sci.electronics
Document_id: 53985
From: hughes@jupiter.ral.rpi.edu (Declan Hughes)
Subject: Manual for Eprom Blower (Logical Devices Prompro-8) Wanted


  I have an eprom blower made by Logical Devices and the
 model name is Prompro-8, but I have lost the manual. Does anyone
 have a spare manual that they would like to sell ?

   Declan Hughes
   hughes@ral.rpi.edu

Newsgroup: sci.electronics
Document_id: 53986
From: 880518l@dragon.acadiau.ca (Nelson Langille)
Subject: Re: Need Info on DSP project

There is a file at the simtel archives called adda10.zip I think that
is for DSP.

Newsgroup: sci.electronics
Document_id: 53987
From: markz@ssc.com (Mark Zenier)
Subject: Re: MC SBI mixer

Mark J. Musone (musone@acsu.buffalo.edu) wrote:
: HI, I was wondering if anyone would be able to help me on twwo related
: subjects. I am currently learning about AM/FM receivers and recieving
: circuits. 
: 
: P.S. any REALLY GOOD BOOKS on AM/FM theory ALONG WITH DETAILED
: ELECTRICAL DIAGRAMS would help a lot.
: I have seen a lot of theory books with no circuits and a lot of
: circuit books with no theory, but one without the other does not help.

A pretty serious book that still seems readable is

Communication Receivers, Principes and Design
by Rohde and Bucher.


Mark Zenier  markz@ssc.wa.com  markz@ssc.com  

Newsgroup: sci.electronics
Document_id: 53988
From: idh@nessie.mcc.ac.uk (Ian Hawkins)
Subject: Making up odd resistor values required by filters

When constructing active filters,  odd values of resistor are often required 
(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
capacitor values and cope with the strange resistances then demanded).

Is there a PD program out there that will work out how best to make up such
a resistance, given fixed resistors of the standard 12 values per decade?.(1,
1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
q and finding prefered values x,y and z.


			Cheers
				Ian H  


Newsgroup: sci.electronics
Document_id: 53989
Subject: Re: electronic parts in NYC?
From: david tillyer <DATCC@CUNYVM.BITNET>

Does anyone here know where I can find a modem and comm. software for
an Apple IIe?  I would prefer in Manhattan, but New Jersey would
work too.  David Tillyer, DATCC@CUNYVM.CUNY.EDU

Newsgroup: sci.electronics
Document_id: 53990
From: tgg@otter.hpl.hp.com (Tom Gardner)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In sci.electronics, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:

> I'm wondering if it's possible to use radio waves to measure the
> distance between a transmitter(s) and receiver?

Yes. It's called RADAR.

> Seems to me that you should be able to measure the signal strength
> and determine distance. This would be for short distances (2000 ft),
> and I would need to have accuracy of 6 inches, or so.

Depends on the environment: in a static environent such as a waveguide yes, in
a dynamic environment (with objects moving about) the multipath kills this
concept.

> How about measuring vertical distance as well, any chance - or am I getting
> ridiculous?

What is the difference between vertical and horizontal?

> What frequencies would be best for this? Or does matter?

This depends on the required range, the required accuracy, the allowable
ambiguity in range, the frequencies the FCC (etc) allow you to use.

Newsgroup: sci.electronics
Document_id: 53991
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: Pink Noise

Tony Wayne writes:

>What is Pink noise and how is it used in sound experiments?
>-tony

Pink noise is a random signal with more low-frequency components
than white noise.

If you look at the frequency spectrum of white noise at a frequency
analyzer, you will find that the spectrum power density is flat, which
means that every frequency is present in the noise signal.

Often pink noise is obtained from white noise by integrating of low-pass
filtering a white noise signal. Therefore pink noise contains much more
low-frequency components.

The effect of pink noise is sometimes used to simulate thunder or roaring
animals. An additional low-pass filter with variable cutoff frequency will
explain you why.

Enjoy it.

Wouter.

Newsgroup: sci.electronics
Document_id: 53992
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: 8x oversampling CD player

mcmahan@netcom.com (Dave Mc Mahan) writes:

> In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>>
>>>I just bought a new portable CD player for the office, and I notice that
>>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box.  Now while I think
>>>I understand what oversampling is (the rate of discrete "samples"
>>>exceeds the highest frequency component of interest by some factor),
>>>I don't understand this "8 TIMES" business...  It seems to me that when
>>>I bought my first CD player (was it REALLY 10 years ago?!), the specs
>>>said "4 TIMES" ...  Could someone please tell me whether I'm getting
>>>senile?  If I'm not, then what good does it do for the player to take
>>>samples at a higher rate?  

>>The data is only ever read once (barring mistracks and such, of course),
>>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>>Oversampling takes two discrete data points, and interpolates n-1 points
>>between them for n times oversampling.  When I asked, people said that the
>>interpolation was not simply linear interpolation, but significantly more
>>complicated.

>You are quite correct in your understanding.  The filtering is not
>interpolation, as that would distort the frequency content of the signal

They do interpolate - it's not linear interpolation though. You are correct
that the frequency content is not altered (more specifically, the baseband
spectrum is preserved, and so is every Nth image spectrum. The other
(N-1) in N image spectra are removed, where N is the oversampling rate)

>you are listening to.  Generally, these players run the samples thru an
>all-pass filter network.  I have done this for ECG waveforms from a person's

Ideally the filter has a gain of 1 from 0Hz to 22050Hz, and a gain of 0
from 22050 to the new Nyquist frequency. In practice a finite transition
band is required, and there is also a certain amount of pass-band ripple
and stop-band leakage. With a high order (eg 200 taps) digital filter,
a very good approximation can be easily achieved.

 <<< BIT DELETED ABOUT OBSERVATIONS OF INTERPOLATION FILTER AT WORK >>>

>In case you care, the filtering method uses an FIR (finite impulse response)
>filter.  I'd guess that CD makers use the same kind of method.  Anybody out
>there know the real answer?  I'd say that they use a tapped delay line with
>resistor/op-amp weighting to accomplish the filtering.  This strikes me as
>the most cost effective method for volume production runs.

No, they actually use a digital FIR just like yours, but built in hardware,
on custom VLSI chips for (mainly) economic reasons.

>>Anyway, then, the purpose of oversampling is to move the "effective"
>>sampling rate up to n times 44.1 KHz, in order to use higher frequency
>>antialiasing filters.  For the same quality filter, higher oversampling
>>lets you build cheaper filters, whereas for the same price filter, higher
>>oversamplings lets you build better filters.  So, assuming the quality of
>>all other components in a CD player remained the same, oversampling should
>>allow a manufacturer to produce _slightly_ better sound due to anti-alias
>>filtering.

>Actually, I think the only reason they do this is so that they can say that
>they have a marketting gimic.  I would guess that it is acutally cheaper to
>filter an oversampled signal than not.  You can use sloppier components and
>give the filter a roll-off that isn't so sharp.   It's too bad that they
>charge more for something that (I think) is actually less costly to build.

I guess that the answer is somewhere between the two.

As an interesting (?) aside, some of you out there may be aware of a scheme
used by Pioneer and Wadia, which is called (by Pioneer, at least) Legato
Link. I haven't heard one of these players, but by reading advertising
blurb, and a couple of pseudo-technical articles I deduced that all they
do is build a lousy digital oversampling filter, and let a load of the
first image (ie aliassed) spectrum through. Talking to Bob Stuart (of
Boothroyd Stuart, aka Meridian) confirmed my suspicion. He said that it
sounded awful, but then he would, wouldn't he...

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
Document_id: 53993
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <72020037@otter.hpl.hp.com> tgg@otter.hpl.hp.com (Tom Gardner) writes:
>What is the difference between vertical and horizontal?

Gravity?  Doesn't gravity pull down the photons and cause a doppler shift
or something?





(Just kidding!)


Newsgroup: sci.electronics
Document_id: 53994
From: u009@csx.cciw.ca (G. Stewart Beal)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <C5v13M.C37@bcstec.ca.boeing.com> rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>I'm wondering if it's possible to use radio waves to measure the
>distance between a transmitter(s) and receiver?
>
>Seems to me that you should be able to measure the signal strength
>and determine distance. This would be for short distances (2000 ft),
>and I would need to have accuracy of 6 inches, or so.
>
This would be susceptible to fading, multi-path etc. We used to use a
system at the shop made by Tellurometer in South Africa. It used a
10 GHz signal between 2 units across the distance to be measured.
The 10 GHz was just the carrier: the real signals were several switched
ones around 7.5 MHz or so, whose relative phases at the receiver would
read out the digits of the distance down to 10 cm if needed. The units
came with psychrometers (sp?) to measure the relative humidity and
instructions for correction of the measurements due to RH and temp.
They were rather heavy and required an operator at each end.
Current technology uses polarized reflectors, dual polaization TX/RX
and psuedo-random coding of a radar pulse. about the same resolution
at X band, much better at 47GHz. (Only one end is heavy :-)  ).
 
Regards, Stu Beal, VE3MWM, U009@CSX.CCIW.CA,
National Water Research Institute, Burlington, Ontario, Canada.
 
"We'd made it through yet another nuclear winter and
 the lawn had just trapped and eaten it's first robin." - Kyle J. Spiller


Newsgroup: sci.electronics
Document_id: 53995
From: djbarnes@eos.ncsu.edu (DONALD JAMES BARNES)
Subject: Re: arcade style buttons and joysticks


In article <1r53r8INNq0i@gap.caltech.edu>, franko@cco.caltech.edu (Frank Filipanits) writes:
> > > Can anyone tell me where it is possible to purchase controls found
> > > on most arcade style games.  Many projects I am working on would
> > > be greatly augmented if I could implement them.  Thanx in advance.
> 
> >HAP controls just outside Chicago sells these.
> >						Andrew MacRae
> 
> Actually, it's HAPP, and some of their equipment can be found in the 
> Parts Express catalog (1-800-338-0531).  They show switches for $2,
> joysticks for $13 and trackballs for $80.  They also have pinball parts.


You're right, it is HAPP Controls, Inc., but you can buy direct from them.  I
don't have a phone number with me, but anyone interested in it can email me for
it.  I don't remember their button price, but the joystick price was $8.95
per dozen at last check.  Should be slightly higher for one or two, but cheaper
than Parts Express.  As for the trackballs, i don't know the new price either.
But I can sell you rebuilt arcade trackballs for $50.  That includes new rollers
and new bearings (when nec.).  I also have a pile of used joysticks and buttons
that i would be willing to sell.  Please email to address below if interested.

--Donnie

///////////////////Please note the new email address below////////////////////
******************************************************************************
Donald Barnes	         |         "Coach, I'm having blackouts."
barnes@yoda.csc.ncsu.edu |
Computer Engineering	 |  "Kind of a nice break in the day, isn't it Sam."
N.C. State University    |			
******************************************************************************

Newsgroup: sci.electronics
Document_id: 53996
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

That depends entirely upon the advertiser whose number you circled.
Radio Electronics compiles all of the cards, then each advertiser
gets a computer printout of the names and addresses of all of the readers
who circled their number. Some magazines also provide the data on
self-adhesive labels, and the really big magazines provide the
data on computer disk.

The advertiser decides what to do with the data they get. You will
notice that the Radio Electronics information card (commonly called
a "bingo card" in the industry) includes lines for a company name
and a business phone number. My guess would be that the big, national
advertisers make a distinction between hobbiests and professionals as
best they can. For example, if you include Motorola as your company
and include a business phone (and a mail stop), Tektronics will probably
send you a copy of their hard-bound catalog and have a sales engineer
call you about a week later. If you leave it blank, odds are they
will send you a slick brochure and direct you to a local retail
outlet. Medium and small companies are more likely to send you th
e whole catalog. And then some companies, like Digikey or Jameco, have
nothing to mail out accept the catalog.

A couple of other interesting points about bingo cards: Free, industry
magazines like EDN and such also log your card to their computer. They
use the information at least three ways. They note that you really do read
the magazine and are more likely to continue your subscription or push
you, through repeated mailings, to re-subscribe. They also compile
how many people requested which data for their marketing demographics.
This way thay can tell a prospective advertiser that "23% of readers
requesting data were interested in capacitors." And finally, some
magazines rent lists of readers who request certain information. For
example, Tektronics can rent a list of everyone who requested information
about test equipment OTHER THAN TEKTRONIC's, in the past 6 months.

The other point, in the data the advertiser receives, many magazines
include how many items you circled on the card. If they want, the
advertiser can attempt to cull out the "literature collectors" from
the serious potential customers.

"Can you say qualified sales leads? I thought you could."

What's the BEST way for a hobbiest to deal with bingo cards?

  Never circle more than 8 number on the card. If you want more
  than 8 items, use the second card and mail it a couple of
  weeks later.

  If you are really, really serious and you really, really want
  the information, CALL THE ADVERTISER AND ASK! This will also
  cut about 15 days off the the response time. Virtually
  everyone takes a voice on the phone more seriously than data
  on a computer printout.

  To help insure you keep getting a trade magazine that you're
  not really "qualified" for, send in a bingo card at least every
  other month and circle two or three numbers.

  Include a business name and phone number, even if it's your house.
  Advertisers almost never call. 

John Schuch
  publisher of: The Arizona High-Tech Times
                The Arizona Electrical Journal
                The Arizona HVAC News
  (all of which have bingo cards)



Newsgroup: sci.electronics
Document_id: 53997
From: bill@occs.cs.oberlin.edu (Bill Mohler)
Subject: Need Hydrophone Info.


I don't know much about Hydrophones, so I'm looking for any information
that will help avoid problems I haven't thought of! I would like an 
inexpensive hydrophone and amplifier with tape (line level) outputs...
something like Edmund sells for $250. They also sell just the microphone
(hydrophone) head for $24, but how does one construct the enclosure?
Any information would be greatly appreciated, Thanks!

Bill Mohler
bill@occs.cs.oberlin.edu

Newsgroup: sci.electronics
Document_id: 53998
From: mjcargil@dux.dundee.ac.uk (M.J.Cargill Psychology ext 4621)
Subject: VIdeo recording of a vga screen

Hi all,

I think the subject says it all - does anyone know how to take the rgb/h/vsync from a standard vga connector and record them on video tape??

Any help is appreciated!


Mark J Cargill

WHY??  I have a program for the PC that I want to videotape so that I can show
people how the program works at a presentation I am giving.


Newsgroup: sci.electronics
Document_id: 53999
From: wayne@r-node.hub.org (Wayne Dawe)
Subject: Flexible solar cells

Two or three years ago I saw a report on TV about a company that had 
developed a method of making solar cells on a flexible substrate. My
failing memory has convinced me it was some flexible metal. I now have
an application that requires a flexible solar cell and was hoping someone
out in netland knows something about this company or a similar product.
Any help would be greatly appreciated.
-- 
Wayne Dawe                    (pick a path, any path but don't send me
wayne@r-node.hub.org           anything bigger than 15K)
wayne@r-node.gts.org   wayne@r-node.pci.on.ca     wayne@r-node.UUCP

Newsgroup: sci.electronics
Document_id: 54000
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: electronic parts in NYC?

In article <1993Apr21.162414.18000@trintex.uucp> elr@trintex.uucp
	(Ed Ravin) writes:
>Trans-Am Electronics, Canal Street near 7th Ave -- lots of surplus type
>stuff.

They've been out of busines for years.

>Several other electronics or "surplus" type places are still on Canal
>Street.

Not any more.  About 2 years ago they all closed.
When Ramco/Electronics city closed, it took weeks and many
dumpsters to clear everything out (so I heard).
There are a few places that sell connectors and phone wires,
but no chips, capacitors or discrete stuff.

Sylvan/Wellington is still on Broadway and Canal, but they're
not cheap, and not surplus.  It's mostly a TV repairman's store.

-- Jeffrey Jonas
jeffj@panix.com
-- 
Jeffrey Jonas

jeffj@panix.com

Newsgroup: sci.electronics
Document_id: 54001
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Long distance IR detection

In article <wb9omc.735430855@dynamo.ecn.purdue.edu> wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick) writes:
>Duane
>	Yeesh, you WILL be nailing those IRLEDs.  May I suggest getting your
>mitts on the Siemens SFH484-2 IRLED?  This unit is designed to take some big
>current pulses if you can get your duty cycle down a bit.  It will output
>nearly a watt (975 mW) with REAL short duty cycle times.
>
>(nice thing about the SFH484-2 is that it is CHEAP.  I got mine for about
>50 cents a piece, even though I had to buy 100 of them....)

Are you saying that you have some extras that you would like to do some cost
recovery on?  I may be interested.  I think for practical and cost reasons I
am limited to envelope detection so that leaves me with only increasing the
output power and increasing the optical gain at the receiver as methods to
extend range.

>	BTW, I have seen IRLEDs with outputs up to 6 watts...honest,
>6 WATTS.  I don't have the book here at work so I can't recall the company
>name.  The 6 watter ain't cheap, around $108 but if you want some power,
>mamamia, that's pretty hot.  They also have a 4 watt, a 2 watt and a
>1 watt device in their line, and will sell small quan. to individuals.
>If you are interested, I can find the book at home and get the
>pertinent info.

Yes I'm interested in the company name.  I have access to an extensive data
book collection.  With that kind of power, are we getting into an area where
eye safety is getting to be a problem.

>	Now, as for the position detector, you might try ELTEC in Florida.
>Phone number listed in the 92/93 ETID is 904-253-5328.  They seem like
>nice people.  Their specialty is passive infrared detection devices,
>so they might be able to help you out.

They are a long way from me but they might be a better source than I can find
around here.

>	I'm curious about your applications if you don't mind saying.
>The device sounds like it could be useful in a lasertag game, although you'd
>need to up your carrier signal concept to 58.8 KHz......

I'm keeping my application confidential for now.  Raising the frequency should
be no problem, in fact one respondent to my question said that I may not have
to mimic the 50% duty cycle normally used by IR detector chips.

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
Document_id: 54002
From: sburton@dres.dnd.ca (Stan Burton)
Subject: Re: Long distance IR detection

In article <1993Apr22.060607.12380@macc.wisc.edu> jvannes@vms.macc.wisc.edu writes:
> You are probably referring to the products of
>
> 		Opto Diode Corp.
> 		750 Mitchell Road
> 		Newbury Park Ca 91320
> 		805 499-0335
>
> The make some amazing IRLED's.  The really high-powered devices are arrays of
> 3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
> response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
> designed as illuminators for IR vision systems.

Jeez, that should do it.

> I would also be interested in the application here.  I work with a Dance and
> Technology program, and want to build something to track dancers on a 30 foot
> wide stage from 50 feet away.

Very interesting application, controlled lighting and environment, moderate
distances ... might be more interesting than my application.  Just a thought,
you could use a roof mounted IR sender, similar in operation to a TV remote
control that tells each persons coded IR pulser to send a pulse.  A Hamamatsu
detector, as was mentioned in a previous message in this thread, would give
the current position.  Store and collate this on a computer and you could
replay the movements on the screen.  Interesting!

--

Stan Burton (DND/CRAD/DRES/DTD/MSS/AGCG)                 sburton@dres.dnd.ca
(403) 544-4737     DRE Suffield, Box 4000, Medicine Hat, AB, Canada, T1A 8K6

Newsgroup: sci.electronics
Document_id: 54003
From: plumpe@oasys.dt.navy.mil (David Plumpe)
Subject: Re: Making up odd resistor values required by filters

In sci.electronics, idh@nessie.mcc.ac.uk (Ian Hawkins) writes:
>When constructing active filters,  odd values of resistor are often required
>(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common
>capacitor values and cope with the strange resistances then demanded).
>
>Is there a PD program out there that will work out how best to make up such
>a resistance, given fixed resistors of the standard 12 values per decade?.(1,
>1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant
>recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with
>q and finding prefered values x,y and z.

    Since you're worrying about the third decimal place, I assume you're
using 1% tolerance resistors and capacitors?


Newsgroup: sci.electronics
Document_id: 54004
From: jackp@NETSYS.COM (Jack Powers)
Subject: NTSC horiz & vert drive from black burst?

I would like to hook up some cameras that were recently donated to our
local community cable TV station which have sync inputs in the form
of horizontal and vertical drive. Our station sync is a black burst
which works fine with other boxes with "genlock" style inputs. Can
anyone point me at a design, article, or whatever showing how to produce
the horizontal & vertical drive signals? Thanks in advance.
Jack Powers


Newsgroup: sci.electronics
Document_id: 54005
From: schuster@panix.com (Michael Schuster)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

It varies. You may get a catalog or price list from the advertiser, or
if the ad was a specific product - a slec sheet on that product or line.


-- 
Mike Schuster       |        schuster@panix.com | 70346.1745@CompuServe.COM
------------------- | schuster@shell.portal.com | GEnie: MSCHUSTER

Newsgroup: sci.electronics
Document_id: 54006
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <1993Apr21.141137.863@imag.fr> schaefer@imag.imag.fr (Arno Schaefer) writes:
>In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
>|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
>>>	I guess what I am saying is that your question is difficult, if not
>>>impossible, to answer. What exactly do you want to know?  Do you need a good
>>>one for a project you are working on? How secure must it be?  Are you trying
>>>to crack one that someone else has used?  I can probably make suggestions,
>>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>>legally, to tamper with copy protection.  It can also lead to corruption of
>>>files which you necessarily do not have back ups of (being as they are copy
>>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>>practical applications, and are merely curious?
>>>	Please clear up those questions, and I'll try to help as much as I
>>>can.
>> 
>> May we interpret this as an offer to volunteer as editor for a
>> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>> an initiative! *I* will volunteer to ask some of the questions, if you will
>> provide the answers :-)
>> 
>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>pose: to keep the honest buyer from making (legal) backup copies. It will
>definitely not stop any pirates. If you want to protect you soft, supply a
>good documentation and support. This is IMHO the *only* way of effectively 
>protecting software.

There are several types of copy protection, and the point is to make sure the
user is using a legitimate copy.  The simplest and virtually fool-proof way is
for the program to somehow fixate itself to the machine it was installed on
(some sort of checksum, serial number, whatever) so a copy put on a different
machine (NOT installed from original disks) will not work.  

The program is definitely backupable, if restored to the same machine (depends
on the programmer...  don't use a disk drive characteristic!)  If the user 
did an upgrade to the machine, he/she should reinstall all programs any way.
No document look-up, no disk wear-and-tear!

I did not say that the originals would allow only one install.  The user's 
conscience should do that.

I know, I'll get flamed for this...  But with the increasing number of "casual"
users who either unknowingly or don't care about the software copyrights
(It's the truth.  I have "friends" who ask me for copies of my latest games
all the time, and when I refused, they went after somebody else.), casual
pirating is becoming more of a problem.  Some sort of copy protection will
discourage the casual copying.  I've seen what some of my "friends" dug up
somewhere...  Latest and the greatest games, all cracked, WITHIN days of actual
release!  You know how many bytes you need to change in X-wing to disable
the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)  Determined
pirates are unstoppable, given enough time, but their results do not spread 
that far, since pirate boards are not that well-known, and easily tracked once
found by authorities.  It is the "casual" pirates that the copy protection is
determined to discourage.

What I believe the companies should do is implement the above plus
a special patch once the user registers that loudly exclaims upon bootup
"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
Two benefits: 1) encourages registration, 2) cuts down on pirating and
makes it more traceable, because if the patch's registration message is
encrypted, it will be quite hard to change, and therefore provides a
stable trail of who allowed their copy out of their hands, and thus
violated their license agreement.

This way, the legitimate users who does not register will experience minimal 
discomfort (who does major upgrades to their computer frequently?) as only
problem they have is they won't be able to restore to another computer.

The registered users would have proven they are legitmate users and therefore
gains full rights, and can restore to different machines.  On the other hand,
the software company now have a record of where THIS particular copy is 
supposed to be.  If this user's copy was found to be somewhere it was not 
supposed to be, we know who has broken their license agreement.  Of course,
a hacker can break that eventually, but that's not the point, is it?

--Kasey Chang

Newsgroup: sci.electronics
Document_id: 54007
From: mchen@terra.cs.psu.edu (Michael Chen)
Subject: Re: How to the disks copy protected.

If companies compressed their executables with LZW andd did some kind of
encryption in the process, this "change two bytes here" thing would go right
out the window.
--
 Michael Chen			| From the depths of our most lucid horrors |
				| spring our fond hopes and pure desires... |
 mchen@cs.psu.edu		| except what comes from HELL! :-) 7/23/92  |

Newsgroup: sci.electronics
Document_id: 54008
From: rgvander@apgea.army.mil (Richard G. Vanderbeek <rgvander>)
Subject: MAGIC layout editor

I heard that MAGIC has been transported to the Macintosh environment.  Does
anybody know where I can get a hold of this?  Thanks in advance for any
responses.

Rich Vanderbeek
Dept of the Army
Aberdeen Proving Ground, MD   

Newsgroup: sci.electronics
Document_id: 54009
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: IR detector 'cards'???

In article <1993Apr22.030133.23553@monu6.cc.monash.edu.au> craw@yoyo.cc.monash.edu.au (Sebastian Filzek) writes:
>Hi people..
>
>OK heres my problem.... 
>I keep hearing about these little credit card type of things which
>detect IR light....
>
>I think that they are avaliable in the states and even in England, but
>alas I live in Australia.  Could someone please inform me if I can get
>these things over here, and if so where??? and how much???
>

Sure,

Edmund Scientific Company
101 E. Glouchester Pike
Barrington, NJ, 08007-1380
(609) 573-6250

The card is on page 15 of the last catalog I got. The cost ranges
from $19.00US to $80.00US, depending on size and range of wavelengths
the card responds to.

John



Newsgroup: sci.electronics
Document_id: 54010
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

sehari@iastate.edu (Babak Sehari) writes:

>In <1993Apr20.230749.12821@reed.edu> mblock@reed.edu (Matt Block) writes:

>>In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>>>---
>>>
>>>I was wondering, what copy protection techniques are avaliable, and how
>>>effective are they?  Has anyone have any experience in this area?
>>>
>>>                      With highest regards,
>>>                           Babak   Sehari.

>>	Uh oh...
>>	Umm, there are a number of copy protection schemes.  Some involve
>>modifying the physical media, and some involve encryption schemes, &c.
>>	All of the ones that have existed over the course of computing have
>>been successful for a time.  I recall, however, near monthly releases of new
>>ways to "crack" the copy protection scheme of the latest releases.  The fact
>>is, none of them are completely secure, or anywhere near it.  Some are more or
>>less difficult to crack, and some have already been cracked.
>>	I guess what I am saying is that your question is difficult, if not
>>impossible, to answer.  What exactly do you want to know?  Do you need a good
>>one for a project you are working on?  How secure must it be?  Are you trying
>>to crack one that someone else has used?  I can probably make suggestions,
>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>legally, to tamper with copy protection.  It can also lead to corruption of
>>files which you necessarily do not have back ups of (being as they are copy
>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>practical applications, and are merely curious?
>>	Please clear up those questions, and I'll try to help as much as I
>>can.

>>	Incidentally, the "Uh oh..." at the top is indicative of the dread
>>anyone who has watched their friends hacking equipment be carted off feels
>>when they are asked how to hack.  The area you are broaching is wrought with
>>dangers, many of which include breaking the law, or at least addressing it
>>(from one side or the other.)

>>Matt

>I have written a program and I want to market it.  I would like certain degree
>of protection, since my main custmers are individuals and not the 
>cooperations.   I know laser hole burning method, and hardware key method,
>however, my  software is going to cost only $15.00, so I can not afford that.
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.

>However, I do not want someone to get a copy of PCTools and copy my software.  
>Off course, I never meant to forbid the true hackers from copying, since they
>can develope a better program anyway.

>                      With highest regards,
>                           Babak   Sehari.


>-- 

One of the most popular methods of course is the password check where they ask
you for a word from page x, line y, and word z, but this is pitifully simple to
remove unless you throw some checksums into the main part of your program, and
some self-rewriting code to confuse some people.  Also, make sure that your
program can not be run out a debugger.

Another method of course is to not even make bad sectors on the original disk,
just write a certain key to a certain unallocated sector.   To help you here,
you also must do the code protection schemes mentioned in the first paragraph.
Make sure you also fill the rest of the unallocated parts of the disk with
garbage as well, or they (wanna be crackers) can just look for the junk in
some random sector.

Like you mentioned, there are the laser holed disks and hardware keys, but they
are both expensive and a pain in the butt for the end-user, which you is the
opposite of what you want.

Another configuration that can be used is to save the configuration of the
machine that it is being installed to in the most undecipherable format you can
think of.  If the program does not find that this is the same system, it
requests being installed by the original disk again.  The original disk should
be encrypted, compacted, have many sectors that should be checked, and anything
else you can think of to make sure that the original cannot be copied.  Once
again, you MUST put code-encryption, self-rewriting code, and multiple CRC
checks in the program to make sure that it does not get changed.  Among other
things, this also protects your program from virii.  If the program detects a
change in its code, tell the user that a virus has been detected in the
program.  Tell them the program is "VIRUS SECURE", and remember, you have
helped the world kill some pirating and kill some viruses.  Feel good.

I hope that I have helped.  Have fun.  Knock some cracking out (well, you can't
do it, everything that can be written can be cracked, but you'll piss'em off in
the process!). Goodbye.

What is the program that will be sold?
--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54011
From: lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick)
Subject: Re: subliminal message flashing on TV

In article <293@kc2wz.bubble.org> bob@kc2wz.bubble.org (Bob Billson) writes:
>kennehra@logic.camp.clarkson.edu (Rich"TheMan"Kennehan) says:
>>Hi.  I was doing research on subliminal suggestion for a psychology
>>paper, and I read that one researcher flashed hidden messages on the
>>TV screen at 1/200ths of a second.  Is that possible?  I thought the
>
>Take a look over in alt.folklore.urban.  There is a thread about subliminal
>messages on TV.  The fact that subliminal messages don't work aside, an image
>can't be flashed on a TV screen fast enough to not be noticed.

Well, yes and no.  The _image_ can't be on the screen less than 1/30
of a second, but a _mixture_ of images that's about 90% of the field
that was supposed to be there and 10% of the 'subliminal' addition
could be overlaid for one field, producing the same overall effect to
our sluggish retinae of a discrete image projected for 1/300 second.

..although, like the previous poster, I have to reserve my doubts
about the effectiveness of said discrete image in steering my
subconscious around ..

-- 
<BGB>
lihan@ccwf.cc.utexas.edu        /   The only reason the world hasn't
(really Bruce Bostwick)        /   dissolved into total chaos is that
from the great state of TEXAS /   Murphy's Law also applies to Murphy.

Newsgroup: sci.electronics
Document_id: 54012
From: johne@vcd.hp.com (John Eaton)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

Robert G. Carpenter (rgc3679@bcstec.ca.boeing.com) wrote:
: I'm wondering if it's possible to use radio waves to measure the
: distance between a transmitter(s) and receiver?
: 
: Seems to me that you should be able to measure the signal strength
: and determine distance. This would be for short distances (2000 ft),
: and I would need to have accuracy of 6 inches, or so.
: --------------------
You might try looking at whats available in laser locating systems. They
work best for close work( 1 mile and under).

RF is used for much longer distances in two major modes. Transponder and
phase measurment. Transponder requires you send a pulse to another station
and it returns it to you and you measure the round trip time minus the
receiver time.

Phase measurements require two or more transmitting stations sending the
same frequency signal multiplexed in time. A receiver can pick them up and
measure the phase shift between signals. Maps can be drawn that plot the
Lines of Position that correspond to a certain phase shift between two
stations. 

John Eaton
!hp-vcd!johne



Newsgroup: sci.electronics
Document_id: 54013
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

ketil@edb.tih.no (Ketil Albertsen,TIH) writes:

>In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:

>>	I guess what I am saying is that your question is difficult, if not
>>impossible, to answer.  What exactly do you want to know?  Do you need a good
>>one for a project you are working on?  How secure must it be?  Are you trying
>>to crack one that someone else has used?  I can probably make suggestions,
>>assuming the activity is strictly legal.  (In general, it is a BAD idea,
>>legally, to tamper with copy protection.  It can also lead to corruption of
>>files which you necessarily do not have back ups of (being as they are copy
>>protected,) which can be devestating.)  Do you have absolutely no ideas for
>>practical applications, and are merely curious?
>>	Please clear up those questions, and I'll try to help as much as I
>>can.

>May we interpret this as an offer to volunteer as editor for a
>"Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>an initiative! *I* will volunteer to ask some of the questions, if you will
>provide the answers :-)

>Ketil Albertsen

That's great.  Read my article.  Edit out the personal formality, and save.
--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54014
From: ggruscho@nyx.cs.du.edu (George Gruschow)
Subject: Re: How to the disks copy protected.

schaefer@imag.imag.fr (Arno Schaefer) writes:

>In article <1993Apr21.085848.12704W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
>|> In article <1993Apr20.230749.12821@reed.edu>, mblock@reed.edu (Matt Block) writes:
>|> 
>|> >	I guess what I am saying is that your question is difficult, if not
>|> >impossible, to answer.  What exactly do you want to know?  Do you need a good
>|> >one for a project you are working on?  How secure must it be?  Are you trying
>|> >to crack one that someone else has used?  I can probably make suggestions,
>|> >assuming the activity is strictly legal.  (In general, it is a BAD idea,
>|> >legally, to tamper with copy protection.  It can also lead to corruption of
>|> >files which you necessarily do not have back ups of (being as they are copy
>|> >protected,) which can be devestating.)  Do you have absolutely no ideas for
>|> >practical applications, and are merely curious?
>|> >	Please clear up those questions, and I'll try to help as much as I
>|> >can.
>|> 
>|> May we interpret this as an offer to volunteer as editor for a
>|> "Copy protection FAQ" ? I am quite sure that I am not alone welcoming such
>|> an initiative! *I* will volunteer to ask some of the questions, if you will
>|> provide the answers :-)
>|> 
>|> Ketil Albertsen

>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>pose: to keep the honest buyer from making (legal) backup copies. It will
>definitely not stop any pirates. If you want to protect you soft, supply a
>good documentation and support. This is IMHO the *only* way of effectively pro-
>tecting software.

>Best Regards,

>Arno

>-- 
>--------------------------------------------------------------------------------
>Arno Schaefer				ENSIMAG, 2e Annee
>Email: schaefer@silene.imag.fr
>Tel.: (33) 76 51 79 95			:-)
>------- No, you're not paranoid - the world is really out to get you -----------

Your wrong.  Never give up.  Update your program as much as possible, with a
very low price of upgrade to registered users (and *PLEASE* make sure you keep
a list of registered numbers!)...

--
-------------------------------------------------------------------------------
George Gruschow                                Death do you gronk.
ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54015
From: swwynen@undergrad.math.uwaterloo.ca (Steve W. Wynen)
Subject: 68008 cross compilers and assemblers (Shareware?)

Can anyone point me to a cross compiler and/or assembler for the Motorola
68008, hosted by a PC compatible.  Preferable Free or Shareware.  

Also does anyone know of a GNU CC port to this chip.

Thanks in advance.


Newsgroup: sci.electronics
Document_id: 54016
From: ngupta@geds01.jsc.nasa.gov (ngupta)
Subject: WANTED A SCOPE

I am looking for a 20/40 MHz scope, in good condition.  Please email me or call me at (713)280-2788.


Newsgroup: sci.electronics
Document_id: 54017
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR detector 'cards'???

craw@yoyo.cc.monash.edu.au (Sebastian Filzek) writes:


>I think that they are avaliable in the states and even in England, but
>alas I live in Australia.  Could someone please inform me if I can get
>these things over here, and if so where??? and how much???

>Also are they really commonly avaliable in the states, and if so, then
>how much are they and who sells them (maybe if I cant get one here, I'll
>write to one of the companies over seas..)

>Anyway.... Thanks in advance...

>Sab
>93


	I got mine for about 7 bucks at Radio Shack.  The instructions
DO say to expose it to light for a while, but mine doesn't seem to require 
very much to make it work.

	I just wish I could get a big sheet of the stuff, abouit 12" x 12"
for a reasonable price.....it isn't cheap, from what I've seen.

Duane


Newsgroup: sci.electronics
Document_id: 54018
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: Long distance IR detection

jvannes@vms.macc.wisc.edu writes:


>You are probably referring to the products of
>		
>		Opto Diode Corp.
>		750 Mitchell Road
>		Newbury Park Ca 91320
>		805 499-0335

>The make some amazing IRLED's.  The really high-powered devices are arrays of
>3, 6, or 9, LED's on a TO-66 header.  The 9-chip model puts out 6.5 Watts in
>response to a 5 Amp, 10 uS. pulse at a .5% duty cycle.  I think  these are
>designed as illuminators for IR vision systems.

	Yeah! that's the guys!

>I would also be interested in the application here.  I work with a Dance and
>Technology program, and want to build something to track dancers on a 30 foot
>wide stage from 50 feet away.

	Yeah, that sounds a lot like lasertag anyway....  :-)

Duane


Newsgroup: sci.electronics
Document_id: 54019
From: dana@lando.la.locus.com (Dana H. Myers)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)

Oh, yeah.  This is a fine place.  We haven't had the "why does concrete
kill lead-acid batteries" thread in at least six months.

>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  

The concrete simply sucks all the electrons out of the battery and drains
them into the ground.

Another explanation, implausible as it is,  is that the lead-acid battery
needs to be periodically charged (topped-off), otherwise the battery
self-discharges and then undergoes irreversible chemical reaction.

Naawwwww.... the concrete sucks the life out.

-- 
 * Dana H. Myers KK6JQ 		| Views expressed here are	*
 * (310) 337-5136 		| mine and do not necessarily	*
 * dana@locus.com  DoD #466 	| reflect those of my employer	*
 * This Extra supports the abolition of the 13 and 20 WPM tests *

Newsgroup: sci.electronics
Document_id: 54020
From: wb9omc@dynamo.ecn.purdue.edu (Duane P Mantick)
Subject: Re: IR remote control receiver

ritterbus001@wcsub.ctstateu.edu writes:

>If you want to buy one, try Radio Shack, or else a TV repair shop can
>probably order one.  BTW - the carrier frequency is 40 KHz, and each
>different TV/VCR/cable box/stereo manufacturer uses a unique pulse
>scheme to perform each different function on their equipment.

	Some TV's, including my RCA set at home, uses simple carriers
which I think run between 32 and 36 or 38 KHz.  There is no tone decoding
in it.  All one has to do to piss the thing off :-) is just hook an
IRLED up to a variable oscillator and tune through.  Wreaks all kinds
of havoc.  :-)

	Similarly, my VCR remote changes channels on my cable box.  Always
seems to change the cable box to channel 5 when you do the pause/play.

	SOOOO, some things do have some overlap to them.

Duane


Newsgroup: sci.electronics
Document_id: 54021
From: anon0188@nyx.cs.du.edu (Einstein)
Subject: I need to access reports on Hall effect Devices.


Does anyone know of the whereabouts of technical reports that
I can access via the Internet?

--
  ______         ___                               
  (/__     . __   (/__) _   . __   /   _   /) _/__  
  (____/\_(_(_____/\_  /-\_(__) )_/_)_(_)_(___/_  
                 (	                         

Newsgroup: sci.electronics
Document_id: 54022
From: wally@Auspex.COM (Wally Bass)
Subject: Re: How to the disks copy protected.

In article <sehari.735357542@du139-213.cc.iastate.edu> sehari@iastate.edu
    (Babak Sehari) writes:
  [stuff deleted]
>Also, at this low price I can not afford people make too many copy of my
>software. Well, I guess say upto %20 illigal copying is ok by me.

You should be clear in your mind what your goal is. Two possible goals
are (1) maximizing you income from your program, and (2) minimizing
the number of illegal copies which get created. Accomplishing (2)
doesn't usually accomplish (1).

Most vendors have concluded that copy protection reduces the number of
normal legitimate sales by far more than it increase sales by virtue
of changing 'copiers' to 'purchasers', and hence merely reduces
revenue.  Most legitimate buyers nowadays (including me) have had bad
experiences with copy protected products (e.g., hard to make a
legitimate backup, incompatabilties when new system on system upgrade,
etc.), and they won't touch them with a ten foot pole.

Wally Bass



Newsgroup: sci.electronics
Document_id: 54023
From: cab@col.hp.com (Chris Best)
Subject: Re: IR detector 'cards'???

> Also are they really commonly avaliable in the states, and if so, then
> how much are they and who sells them (maybe if I cant get one here, I'll
> write to one of the companies over seas..)

----------

Radio Shack, part 276-099, Infrared Sensor Card, $US 5.95

Newsgroup: sci.electronics
Document_id: 54024
From: jackb@mdd.comm.mot.com (Jack Brindle)
Subject: Re: Can Radio Freq. Be Used To Measure Distance?

In article <72020037@otter.hpl.hp.com> tgg@otter.hpl.hp.com (Tom Gardner) writes:
>In sci.electronics, rgc3679@bcstec.ca.boeing.com (Robert G. Carpenter) writes:
>
>> I'm wondering if it's possible to use radio waves to measure the
>> distance between a transmitter(s) and receiver?
>
>Yes. It's called RADAR.
Well, actually not quite. Both Radar and Radio-Altimeters measure distances
by measuring the time required to transmit a signal, then receive its
reflection from a target. Radar generally uses pulses, while Radio Altimeters
use either pulses or a modulated continuous-wave transmission. In the case of
the latter, highly accurate distance measurement can be made. As an example,
the original Bendix ALA-52 Radio Altimeter was accurate to 1/8 foot at 2500
feet altitude.

Note, however that this is a different method of measuring than the poster
originally asked about. The problem with gaining accurate measurements between
a transmitter and a seperate receiver is that you need a highly accurate
time base which starts at the receiver at the exact instant the transmitter
triggers. This cannot be wire connected, since radio waves will actually
travel faster in free-space (air, in this case) than wire (the difference
is called the velocity factor of the cable). So you need to resort to a
common timebase that is automatically corrected for distance, etc. Something
like a PLL connected to a GPS receiver should do the trick, triggering both
the transmitter and receiver simultaneously. Sound expensive? Not too bad,
but plan on spending a few bucks in both equipment and effort.

Why not go to a different method? Surveyors use a laser-light system where again
the reflection time is measured. Why not try this? (Sounds like something a P.E.
should know about anyway ;-).

>> Seems to me that you should be able to measure the signal strength
>> and determine distance. This would be for short distances (2000 ft),
>> and I would need to have accuracy of 6 inches, or so.

This is actually highly inaccurate, since the power output of a transmitter
varies from unit to unit, there are variances in the antenna and transmission
line, and the receiver may also vary, both from unit to unit, and the same unit
over time. You would need to continuously calibrate the entire system. With
the radio altimeter this is also done, but since everything is located at
one place, it is much easier to do. Note especially that the time base for
the R.A. receiver and transmitter is one unit also...

>Depends on the environment: in a static environent such as a waveguide yes, in
>a dynamic environment (with objects moving about) the multipath kills this
>concept.

Nope. FM capture effect says that the strongest signal wins. That is, unless
the two interfering signals are seperated by more than 3 db in signal strength.
This is the one problem that makes altimeters inaccurate at very low altitudes.
Signals bouncing off runways tend to be VERY strong...

>> What frequencies would be best for this? Or does matter?

As high as possible to eliminate outside influence, and also to enhance
attenuation of multipath signals. Radio Altimeters typically use frequencies
around 4 GHz.

Hope this helps...

-- 
==========================================================
Jack Brindle
ham radio: wa4fib
internet: jackb@mdd.comm.mot.com

Newsgroup: sci.electronics
Document_id: 54025
From: goofy@howlin.cs.unlv.edu (David Haag)
Subject: Test

This is just a test to see if this works.


Newsgroup: sci.electronics
Document_id: 54026
From: kthompso@donald.WichitaKS.NCR.COM (Ken Thompson)
Subject: Re: Cable TVI interference

victor@inqmind.bison.mb.ca (Victor Laking) writes:

)Do you know what frequencies chanels 17 to 19 use and what is usually 
)allocated to those frequencies for broadcast outside of cable?

17 is air comm.
18 is amateur
19 is business and public service

-- 
Ken Thompson    N0ITL  
NCR Corp.  Peripheral Products Division   Disk Array Development
3718 N. Rock Road  Wichita KS 67226   (316)636-8783
Ken.Thompson@wichitaks.ncr.com 

Newsgroup: sci.electronics
Document_id: 54027
From: koberg@spot.Colorado.EDU (Allen Koberg)
Subject: Packet Radio on the PC

I'm looking for any and all information regarding packet radio
implementation on the PC.  Software, hardware, whatever.

Please e-mail any info to koberg@spot.colorado.edu.

Thanks

Newsgroup: sci.electronics
Document_id: 54028
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Hi Volt from battery

You might want to get a disposible flash camera, shoot the roll of film,
then take it apart (they're snapped together). We used a bunch of them
at my wedding, but instead of sending the whole camera in, I just took
the film out (it's a standard 35mm canister), and kept the batteries
(they use one AA battery). Sorry, I didn't keep any of the flash electronics.

          Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
Document_id: 54029
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: 600RPM Floopy drives - UPDATE!

In article <1r3j2lINNf13@clover.csv.warwick.ac.uk> csulo@csv.warwick.ac.uk  
(Mr M J Brown) writes:
> 
> Hopefully this should sort it all out .... not bad for 9 quid (normally
                                                         ^^^^^^

Pardon my ignorance of foreign currency and exchange rates, but what is a  
quid, how does it relate to the British Pound (or whatever it's called)  
and what is that in American Dollars??? :-)

Thanks!

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu



Newsgroup: sci.electronics
Document_id: 54030
Subject: help with phone wire: which ones are "tip" & "ring"?
From: mlevin@husc8.harvard.edu (Michael Levin)


I just bought a little gizmo that is supposed to be installed "in
series with the tip or ring lines" of the phone wire. Which ones are
those? Suppose I am holding a regular phone wire, such that the little
plastic tooth (on the little plastic square thing with the naked lead
ends that you plug into the phone) is facing down, and away from me.
Which of the 4 wires that I see is the "tip" and which is the "ring"?
Please reply to mlevin@husc8.harvard.edu.

Mike Levin


Newsgroup: sci.electronics
Document_id: 54031
From: cyborg@kauri.vuw.ac.nz (-xivo-Alex Ivopol)
Subject: Re: How to the disks copy protected.

In article <MCHEN.93Apr22131702@terra.cs.psu.edu> mchen@terra.cs.psu.edu (Michael Chen) writes:
>If companies compressed their executables with LZW andd did some kind of
>encryption in the process, this "change two bytes here" thing would go right
>out the window.

Not entirely true. A friend of mine was having trouble finishing the game
GODS and asked me for help since he could not find a "trainer" (small
patch that lets you play without losing lifes). The game is compressed but
I did find *one* byte which when changed in the original *compressed* file
would not affect the decompression and would also prevent the "shield" in the
game from being tured off turning therefore making you invincible.

There are many other progs whose copy protection was defeated one way or
another and I have seen examples of this with my own eyes. The copy
protection schemes defeated were various such as using protected mode,
compressed executables, progs that load and execute other progs (possibly
compressed), dongles, key disks, etc...

I believe that persistence overcomes even the very best copy protection
schemes.

>--
> Michael Chen			| From the depths of our most lucid horrors |
>				| spring our fond hopes and pure desires... |
> mchen@cs.psu.edu		| except what comes from HELL! :-) 7/23/92  |


-- 
Alex T. Ivopol                           cyborg@kauri.vuw.ac.nz
External User - Victoria University of Wellington - New Zealand
************* I speak for myself and no one else. *************

Newsgroup: sci.electronics
Document_id: 54032
From: dougwong@cco.caltech.edu (Douglas M. Wong)
Subject: Silicon Storage Inc.

I would appreciate very much the address and/or phone # of 
this company. They supposely make analog EEPROMS. Thanks in
advance.

Doug.

Newsgroup: sci.electronics
Document_id: 54033
From: srgxnbs@grace.cri.nz
Subject: Re: CAD Program for Electronics?

>>What I want the CAD program to do is to draw diagrams by
>>dragging elements onto the screen, and in this the elements
>>needed are as diverse as vacuum tubes to ICs (case with pins).
..
try DraftChoice, its not windows but its shareware and object
oriented. Use it with PrintGL for high quality output.

Bruce



Newsgroup: sci.electronics
Document_id: 54034
From: gt4417a@prism.gatech.EDU (SKELTON,JOEL PHILLIP)
Subject: help me, i'm not clever! (how to make power supply?)

I need to make a power supply that can take input from a 
cigarette lighter in a car (12v dc) and drive 7.5 volts
at up to 3.0 amps. I know enough to know that a simple
voltage divider with two resistors won't do it right. Can
such a thing be made from Radio-Shack-able parts without
too much difficulty?

jps
bf

p.s. I've looked for premade things like this at radio shack but
none of it seems to go any higher than about 800mA.


-- 
Joel Skelton   --    North Avenue Trade School, Dept. of Round Things
gt4417a@prism.gatech.edu   (ask for Scooter Technologies, and receive)

Newsgroup: sci.electronics
Document_id: 54035
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: How to the disks copy protected.

In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu  
(Kuo-Sheng (Kasey) Chang) writes:
> 
> There are several types of copy protection, and the point is to make  
sure the
> user is using a legitimate copy.  The simplest and virtually fool-proof  
way is
> for the program to somehow fixate itself to the machine it was installed  
on
> (some sort of checksum, serial number, whatever) so a copy put on a  
different
> machine (NOT installed from original disks) will not work.  
> 

Okay, so what do you do if some part of the machine (presumably the part  
on which the code number or whatever that the program has fixated itself  
upon goes bad, you replace that part, and now your program won't run  
because it's on a "different" computer???

This is, of course, assuming that the program uses something in ROM (like  
the BIOS serial number, maybe?) and not a disk-based code number.   
Obviously if the drive goes bad you'll be reinstalling the stuff anyway.

I work in a computer lab which is part of the university microlab system.   
We have the wonderfully fun task of maintaining well over a hundred  
machines, both PC and Macintosh, as well as administering a network of  
over 50 NeXT machines.  I personally am concerned only with a small lab  
with ten PC's and ten Mac's.  (I'm not the manager, but help him with  
admin often).  IMHO, copy-protection schemes of ANY sort are nothing more  
than a major headache for the legitimate user.  Anyone who wants a copy of  
your program and doesn't care about legality will get a copy.  Period.   
"Pirate board" or no pirate board.  I too have "friends" who blatantly and  
quite successfuly "hack" copy protection schemes practically in their  
sleep.

Let's consider what goes on in our lab.  Almost daily we have at least one  
machine down, sometimes several, due to some goofball screwing up some  
setting or other on a piece of software.  Admittedly, we (being students,  
mostly) are not the world's most efficient and effective network  
administrators, but we try.  Keeping even the twenty machines that are  
(partly) my responsibility even vaguely looking and "acting" similar to  
the average user, and maintaining "behind-the-scenes" consistency is a  
real headache, but not so bad a headache as trying to remember twenty  
different folder locations of Norton Utilities when some guy trashes his  
disk.

Often we have hardware problems at peak "business" times and have to do  
some parts-swapping to get stuff working temporarily. . . .

Well, I'll cut to the chase and quit boring y'all . . ..

The point is, often we have to re-install software and copy configuration  
files etc. from machine to machine.  By far the easiest way we have found  
to do this is to get ONE machine working EXACTLY the way we want to, then  
COPY the complete setup of this machine to the other nine (of that  
machine's type).  This ensures us that (for at least ten minutes) we have  
ten IDENTICAL machines to work with.  Having them networked simplifies  
this considerably, as our major packages (WordPerfect, Windows, etc.) are  
all network versions and thus only one copy to mess with.

Often, however, we need to install a package requested by some instructor  
to one, some, or all of the machines for a special project.  This is  
usually a hand-written or shareware,etc. program similar to what I believe  
the original poster was asking about.  The few we have had with "copy  
protection" schemes have caused nothing but NIGHTMARES for us to maintain  
 . .

In short, don't waste your time with a copy protection scheme.  It's sort  
of like outlawing guns.  The criminals will get your program anyway, and  
you will only be hurting the legitimate, honest user.  Write a good user's  
guide and tech manual, whatever else for your program (PLEASE do this  
REGARDLESS of whether you copy protect the thing!!!), and only distribute  
the manual to LICENSED users.  Jack the price to cut your losses, but  
please take a cue from the major companies (who can admittedly afford the  
costs of illegal copies far better than you) and don't burden the  
legitimate user with a "copy protection" scheme!


Sorry for the tirade, but it's been a long day here . . .. :-)


Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu




> The program is definitely backupable, if restored to the same machine  
(depends
> on the programmer...  don't use a disk drive characteristic!)  If the  
user 
> did an upgrade to the machine, he/she should reinstall all programs any  
way.
> No document look-up, no disk wear-and-tear!
> 
> I did not say that the originals would allow only one install.  The  
user's 
> conscience should do that.
> 
> I know, I'll get flamed for this...  But with the increasing number of  
"casual"
> users who either unknowingly or don't care about the software copyrights
> (It's the truth.  I have "friends" who ask me for copies of my latest  
games
> all the time, and when I refused, they went after somebody else.),  
casual
> pirating is becoming more of a problem.  Some sort of copy protection  
will
> discourage the casual copying.  I've seen what some of my "friends" dug  
up
> somewhere...  Latest and the greatest games, all cracked, WITHIN days of  
actual
> release!  You know how many bytes you need to change in X-wing to  
disable
> the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)   
Determined
> pirates are unstoppable, given enough time, but their results do not  
spread 
> that far, since pirate boards are not that well-known, and easily  
tracked once
> found by authorities.  It is the "casual" pirates that the copy  
protection is
> determined to discourage.
> 
> What I believe the companies should do is implement the above plus
> a special patch once the user registers that loudly exclaims upon bootup
> "REGISTERED TO XXXXX -- address, city, state zip" and disables the  
above.
> Two benefits: 1) encourages registration, 2) cuts down on pirating and
> makes it more traceable, because if the patch's registration message is
> encrypted, it will be quite hard to change, and therefore provides a
> stable trail of who allowed their copy out of their hands, and thus
> violated their license agreement.
> 
> This way, the legitimate users who does not register will experience  
minimal 
> discomfort (who does major upgrades to their computer frequently?) as  
only
> problem they have is they won't be able to restore to another computer.
> 
> The registered users would have proven they are legitmate users and  
therefore
> gains full rights, and can restore to different machines.  On the other  
hand,
> the software company now have a record of where THIS particular copy is 
> supposed to be.  If this user's copy was found to be somewhere it was  
not 
> supposed to be, we know who has broken their license agreement.  Of  
course,
> a hacker can break that eventually, but that's not the point, is it?
> 
> --Kasey Chang

Newsgroup: sci.electronics
Document_id: 54036
From: lsg001@cck.coventry.ac.uk (Graham Wilson)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr21.170932.18356@news.columbia.edu> kn1@cunixa.cc.columbia.edu (Kimball Ng) writes:
>kolstad@cae.wisc.edu (Joel Kolstad) writes:
>
>>One other thing... there are bubblejets, and then there are BubbleJets.
>>There are a few bubblejets out there that produce rather mediocre output
>>(such as HP's dinky little BubbleJet), whereas most produce really good
>>looking output (such as HP's DeskJets).  IBM and Canon both produce some of
>>the really good style bubblejets.


** I am considering either an inkjet or bubble jet printer. I've seen
   inkjet printers and I was impressed with the near lazer quality.

   I have heard a lot of bad things about the cheaper bubble-jet printers.
   Does the ink smudge very easily and take a long time to dry ?

   Thanks.


   
-- 
          T 3/4 c2 l1(s) hbl d- a w+ c- y e++ g f t+ k++ s++ m1+
         *      Graham Wilson      *  lsg001@cck.coventry.ac.uk  *
         *     LL.B.  Law  III     *     Coventry  University    *
          S8  b+  g-  l--  y+  z/   n--  o++  x+  a-  u+  v-  j++

Newsgroup: sci.electronics
Document_id: 54037
From: cohen@GOMEZ.phys.virginia.edu
Subject: MOV advice please?

Hello,

Can somebody tell me what kind of MOV's are most useful for a computer
surge protector?  Radio Shack have 2 types, both rated 130V, one for
a 10A current and the other for 20A.  On the other hand, commercial surge
protectors I have seen claim a clamping voltage of 330V-400V, which SEEMS to
me in imply a rated voltage of about 250V (250V * SQRT(2.)=353).

What is the right kind?

While at it, ow important is really the EMI/RFI module?  Is there really any
noticable level of such noise in the power line?

Please-  E-MAIL to me, as this group has too much volume for me to be able
to follow.

Thanks!


Newsgroup: sci.electronics
Document_id: 54038
From: tomc@cirrus.com (Tom Crawford)
Subject: Re: what to do with old 256k SIMMs?

In <1r3mmnINN4p1@master.cs.rose-hulman.edu> henslelf@nextwork.Rose-Hulman.Edu. (Lige F Hensley) writes:

>In article <120466@netnews.upenn.edu> jhaines@eniac.seas.upenn.edu (Jason  
>Haines) writes:
>> 
>> 	I was wondering if people had any good uses for old
>> 256k SIMMs.  I have a bunch of them for the Apple Mac
>> and I know lots of other people do to.  I have tried to
>> sell them but have gotten NO interest.
>> 
>> 	So, if you have an inovative use (or want to buy
>> some SIMMs  8-) )
>Sure I'll give you 10 bucks for all of them

I think they are really neat to put onto key rings.  When somebody
makes the mistake of asking about it, you can *totally* geek out.

tc

Newsgroup: sci.electronics
Document_id: 54039
From: mkrajci@wilkes1.wilkes.edu (Martin K.)
Subject: Tunnel diodes on I-G SPICE


Does anybody have an idea how to model a tunnel diode on SPICE?
Thank you.

Martin Krajci mkrajci@wilkes1.wilkes.edu

Newsgroup: sci.electronics
Document_id: 54040
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Power, signal surges in home...

In article <1993Apr21.025500.8804@porthos.cc.bellcore.com>  
patter@dasher.cc.bellcore.com (patterson,george r) writes:
> In article <1993Apr20.232804.24632@mprgate.mpr.ca>  
vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
> >kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
> >
> >>My car, unfortunately, has so much computer junk under the hood that  
it's
> >>astonishingly sensitive to RFI.  
> >
> >Hmmmmm... this has possibilities:
> >If the police are in pursuit of a vehicle, maybe they can bombard it  
with
> >high energy RFI.  :-)
> 
> Right. So all the cops will be buying antique muscle cars for chase  
cars;
> otherwise the *police* cars will die too!

I wonder if you could focus the RFI "gun" so the cops wouldn't have this  
problem???

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
Document_id: 54041
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: Radar detector DETECTORS?

In article <C5usK6.H2H@athena.cs.uga.edu> mcovingt@aisun1.ai.uga.edu  
(Michael Covington) writes:
> There is or was a microwave tower next to Florida's Turnpike, and you
> could watch the cars hit the breaks as they came in sight of it every
> morning...
> 

Funny . . . I and most of the detector-owning friends I have, are  
generally able to *REMEMBER* such things as nearby microwave towers and  
radar detectors going off in EXACTLY the same spon EVERY DAY . . ..

I know on I-64 at the Grayson, KY exit, there's a store just off the side  
of the road (think it's a Liquor store . . .) with what must be a security  
system that would make most federal prisons proud.  It's the only thing  
I've ever driven by (besides a cop) that puts my Whistler in "Oh my God  
he's Right Behind You!!!!" mode . . ..  I simply ignore the detector and  
use my eyes when I drive by that store . . . 40 seconds later, all's quiet  
on the front and no problem.


:-) :-)

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
Document_id: 54042
From: noeler@xanth.CS.ORST.EDU (Eric Richard Noel)
Subject: Re: How to the disks copy protected.

>
>>Hey, now will you stop encouraging him? Copy protection only serves one pur-
>>pose: to keep the honest buyer from making (legal) backup copies. It will
>>definitely not stop any pirates. If you want to protect you soft, supply a
>>good documentation and support. This is IMHO the *only* way of effectively pro
>>tecting software.
>>Best Regards,
>>Arno

I strongly disagree. I think most pirating is done by amateurs, who won't
copy the program if "diskcopy" can't do it.
If you're talking a 20% max goal of pirated copies, I bet that anything that
will beat diskcopy, and can't be easily copied from a hard drive, will
suffice.
I hate hard copy manuals, and would rather have all docs online - *not*
because I want to copy the program, but because its usually faster and
and convenient than sifting through an old book I can't find.

Off deeper end-> Why does everyone think they need to be able to make a 
backup copy? Almost all new software must be installed to the hard disk,
so you are left with the originals as your backups. I think its a waste
of time, space, and money, as well as it makes it to tempting to "lend"
out the backups. 


No flames intended - just my thoughts.

Eric

Newsgroup: sci.electronics
Document_id: 54043
From: lsg001@cck.coventry.ac.uk (Graham Wilson)
Subject: Contracts


** For my computer law module I have been asked to write a computer 
   contract for the supply of computer software to a business. The
   software is being especially written for the company.

   Would anyone, per chance happen to have a copy of a computer
   contract on their system which they could mail me.

   If anyone has a computer contract but it contains sensitive 
   material then I can assure them that it will remain confidential
   and I will not pass it on, or allow anyone else to view it.

   Thanks.




-- 
          T 3/4 c2 l1(s) hbl d- a w+ c- y e++ g f t+ k++ s++ m1+
         *      Graham Wilson      *  lsg001@cck.coventry.ac.uk  *
         *     LL.B.  Law  III     *     Coventry  University    *
          S8  b+  g-  l--  y+  z/   n--  o++  x+  a-  u+  v-  j++

Newsgroup: sci.electronics
Document_id: 54044
From: cph@dmu.ac.uk (Chris Hand)
Subject: Re: Lead Acid batteries & Concrete?

Carter Ames (camter28@astro.ocis.temple.edu) wrote:
:   Why does a lead acid battery discharge and become dead (totally unuseable)
: when stored on a concrete floor?  

It could be that you stored it somewhere that it could become covered
by moisture or damp air, which would short out the terminals.

The same thing happens to my car (Citroen 2CV) -- damp gets under the
bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.

The solution (for the car) is to clean the plug leads and spray with
WD-40 (moisture repellant).  If damp *is* the problem, then storing the 
battery off the ground may help.  I'm not sure if spraying with WD-40
would be safe since it is very flammable (high percentage petroleum).

Just a thought...

Chris

-- 
Chris Hand, Lecturer                Internet mail: cph@dmu.ac.uk
Dept of Computing Science,          Voice: +44 533 551551 x8476
De Montfort University, The Gateway,  Fax: +44 533 541891  FIDOnet: 2:440/32.50
LEICESTER, UK   LE1 9BH             >> Linux: *free* unix for IBM PCs! <<

Newsgroup: sci.electronics
Document_id: 54045
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.
>
>thanks
>camter28@astro.ocis.temple.edu

I am not a battery expert, but from recent reading, a lead acid battery
will self discharge at a relatively high rate, and if stored in a discharged
state, will develop a condition I think is called sulfation.  In storage,
either the electrolyte should be removed and replaced for use (fat chance
I'd ever do that at home), or the battery should be stored on a trickle
charge.  I have also (I think) read that the condition may be reversable
if hooked up to a current limited charging circuit fro a LONG period of time.
The refernce I remember is to use C/50 (where C is the amp hours) as the
charging circuit, and leave it hooked up for weeks.  Some of this may
only apply to Gel type cells, but I suspect the same applies to the liquid
type.

Richard Dell


Newsgroup: sci.electronics
Document_id: 54046
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: A question about 120VAC outlet wiring.

In article <1993Apr22.004728.6736@mtu.edu> cmwolf@mtu.edu (Engineer by Day - Asleep by Night) writes:
>Dave Martindale (dave@imax.imax.com) wrote:
>: They require two separate grounds.  One ground goes to the ground pin
>: of the outlet, and the other ground wire is connected to the outlet's
>: mounting tabs (and thus grounds the box and faceplate screw and metal
>: faceplate, if any).
>
>I thought the ground WAS connected to the metal frame on the socket.
>
>-- 
>------------------------------------------------------------------------------
>Christopher Wolf             Electrical Engineer                cmwolf@mtu.edu
>------------------------------------------------------------------------------
>         Remember, even if you win the Rat Race - You're still a rat.

Not in isolated ground recepticles (usually an unusual color, such as orange
or yellow) often used in low noise, low leakage applications, as mentioned
earlier in the thread.

Richard Dell


Newsgroup: sci.electronics
Document_id: 54047
From: regmad@gsusgi2.gsu.edu (Michael de Kraker)
Subject: Re: Packet Radio on the PC

koberg@spot.Colorado.EDU (Allen Koberg) writes:

>I'm looking for any and all information regarding packet radio
>implementation on the PC.  Software, hardware, whatever.

>Please e-mail any info to koberg@spot.colorado.edu.

>Thanks


	Try rec.radio.packet

 
     _______  ______
    /        /        /       /    Michael A. de Kraker
   /        /______  /       /     Georgia State University  404-651-2390
  /    ___        / /       /      Internet:REGMAD@GSUSGI2.GSU.EDU
 /_______/ ______/ /_______/       BITNET  :REGMAD@GSUVM1  PACKET:KD4FKW@W4QO
 
   To iterate is human, to recurse devine
 

Newsgroup: sci.electronics
Document_id: 54048
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Subject: Re: UART needed (really BREAK detect)

In article <alan-210493163447@17.129.12.26> alan@apple.com (Alan Mimms) writes:
>Actually detecting a BREAK is done by watching for a "character" containing
>all zero bits with the framing error resulting from its receipt.  This

True enough, but...

>means that the line stayed in the zero bit state even past the stop bit
>time slot, which basically indicates a BREAK.  There is no special way to
>detect BREAK that I have found other than this -- there's no magic signal
>generated by UARTs, etc.

Zilog SCC:
---------
	RR0[7]:  Break Detect

This is a very popular part, but it has a number of quirks, especially
in HDLC mode.

Signetics 68562 DUSCC:
---------------------
	RSR[2]:  Break Start Detect
	RSR[3]:  Break End Detect

Two of the bits in the Receiver Status Register.  You can enable an interrupt
on either of these bits going high, too.  Also, only one NULL will be put
in the FIFO per break detected.

This is simply the best serial chip I've ever worked with.  _Many_ less
quirks than the SCC, which is IMHO second-best.  (Death to 8250 devices!)

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			One Design to rule them all; one Design to find them.
			One Design to bring them all and in the darkness bind
			them.  In the land of Mediocrity where the PC's lie.

Newsgroup: sci.electronics
Document_id: 54049
From: ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar)
Subject: Re: ATARI 2600 Processors

In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>game machine). 

Wrong, it has a 6507.

>The 2600 had some extra ASIC chips that were basically
>modified graphics chips and PIA's for the joysticks. 

It had one custome chip (not an ASIC in the sense that word is now understood):
the TIA (sometimes known as the 6526, although most other manufacturers list
that as the CIA complex interface adapter.)  TIA stands for Television
Interface Adapter, and it handles sound, paddles and the minimal video hardware
the 2600 possessed.

There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
regulator and (if memory serves) a 555 timer.  That's all.

>Later model 2600
>might have incorporated many of the chips into one ASCI, as the weight
>of the machines and part count decreased a lot over the years.

Not according to the servicing documentation I have here.  The 2600 did not
change intenally very much at all.

>Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
>their games. 

ROMS were mapped into the upper 4K of the 6507's address space.  2K and 4K
games were fine, but later 8K and 16K games needed bank switching.  Atari
(and others) made much of these "huge" cartridges.

>I have no idea how much RAM it had to work with, but I
>would hazard a guess of 2 or 4K RAM. 

Wrong, it had 128 bytes of RAM from the RIOT.  This was multiply mapped into
both page 0 (pseudo-registers) and page 1 (stack), and also throughout the
bottom 4K of memory.  TIA registers also sat in this address space.

As 128 bytes of RAM was somewhat limiting, some later cartridges also carried
RAM themselves, which was interesting as Atari had provided no write line
to the cart.  This was managed by mapping the reads from RAM into one address
range, and the writes into another, but all the time this scheme ate into
the *very* scarce ROM address space.

							Ian.

Newsgroup: sci.electronics
Document_id: 54050
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Making up odd resistor values required by filters

One way to make cheap trimmable resistors is to use a high-wattage carbon
composition resistor, and saw a notch in it with a triangular file.
Of course, you can only increase the resistance, not decrease it.

Newsgroup: sci.electronics
Document_id: 54051
From: ascott@tartarus.uwa.edu.au (Andrew Scott)
Subject: Re: How to the disks copy protected.

cyborg@kauri.vuw.ac.nz (-xivo-Alex Ivopol) writes:

>I believe that persistence overcomes even the very best copy protection
>schemes.

I would expect that CD-ROM software would not even need copy protection.
As the program on a CD-ROM would not fit onto a hard-drive, and it is
impossible for the average (and even not-so-average) user to write to a
CD-ROM, copies of the software (that still work) could never be made.

Hmmm.. now that I think about it.. with a creative TSR, maybe
disk-swapping could be used to simulate files on a single disk. You
would need a tonne of disks though.

>-- 
>Alex T. Ivopol                           cyborg@kauri.vuw.ac.nz
>External User - Victoria University of Wellington - New Zealand
>************* I speak for myself and no one else. *************

Andrew Scott
INTERNET:ascott@tartarus.uwa.edu.au

Newsgroup: sci.electronics
Document_id: 54052
From: mmm@cup.portal.com (Mark Robert Thorson)
Subject: Re: Building a UV flashlight

The simplest and cheapest soft UV bulb is an AR-1 argon bulb (or other argon
bulb).  It works like a neon bulb except it glows purple.  It will cause
stuff to fluoresce.  It requires very little power, just a battery, an
oscillator, and a step-up transformer to about 100 volts.

Electronic Goldmine (602) 451-7454 has several UV lamps, both as pre-built
units and kits.  Ask for their catalog.

Newsgroup: sci.electronics
Document_id: 54053
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Subject: Re: Power, signal surges in home...

In article <1r1jmoINN8mb@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes:
>In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Douglas S. Rand) writes:
>>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) writes:

>>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
>>   that a ham would be running that kind of power from a car.  Ham rigs

>>Not possible either.  You'd need about a 300 amp alternator for
>>just the amplifier.  I can just see it.  You need to slow
>>down on a downgrade,  so you hit the push to talk button.

>Now, that indeed is possible.  A good friend of mine is running about 1 KW
>PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
>the rig an "electronic brake" since the engine noticeably slows when the
>key is down.

It has been a while since I knew the electronics of ham radio, but I seem
to remember that PeP is actually 4x the "real" power.  Which makes 1KW PeP
actually around 250W.  Or was it 2x?  I disremember.

"Effective transmitted power" is also "odd", in that it takes into account
antenna height and geometry.  Which is why a TV station with a 50KW Klystron
might advertise a megawatt (if their antenna is on the top of the
CN tower ;-).

This is like Sears HP ;-)

Though, 1500 real watts still isn't impossible.  About 125-150A with
a 12V alternator, less if the alternator produces higher voltages.

It's only three horsepower (taking into account inefficiencies).  You'll
feel it when you hit the key.  But not too much.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
Ferret list: ferret-request@ferret.ocunix.on.ca

Newsgroup: sci.electronics
Document_id: 54055
From: cstrockb@cs.sunysb.edu (Caleb Strockbine)
Subject: Re: Long distance IR detection

In article <1993Apr22.060607.12380@macc.wisc.edu> jvannes@vms.macc.wisc.edu writes:

   I would also be interested in the application here.  I work with a Dance and
   Technology program, and want to build something to track dancers on a 30 foot
   wide stage from 50 feet away.


Could make for some interesting choreography... light and sound could be 
controlled directly by the position of a dancer on stage, or by the number
of dancers on stage. Neat.

You could even build a spotlight that follows the dancer around on stage!

Can you tell us more about what you're doing? Sounds like a very cool program.

Caleb Strockbine
cstrockb@ic.sunysb.edu

Newsgroup: sci.electronics
Document_id: 54056
From: truemner@mac-truemner.rd.hydro.on.ca (Gary Truemner)
Subject: HELP...high data link

I have a couple applications for high speed data links
1__replacement of ultrasonic signal coaxial cables with fiber optic cable
2__applying fiber optic slip ring for 16 channel ultrasonics inspection
system for CANDU reactor inspection
3__remote data link from ultrasonic pipeline inspection device including
transfer of 16 channels via microwave or other higher speed transfer of
ultrasonic data from remote inspection head.

I would be happy to share sources...other info as acquired.
Please mail me or post here.
.....this is a long term upgrade over the next years _+

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  THANKS...... _/_/_/  truemner@mac-truemner.rd.hydro.on.ca     _/  _/
              _/  _/ ONTARIO HYDRO.Automated.NDT&Welding.R&D   _/_/_/
             _/_/_/ (416)207 6380.FAX:237 9285.Toronto.CANADA _/  _/

Newsgroup: sci.electronics
Document_id: 54057
From: butts#@shocker.ee.twsu.edu (Ronald W. Butts -SUPER ACCT)
Subject: Re: Need to find out numb

In article <6208.442.uupcb@ozonehole.com> gerald.belton@ozonehole.com (
Gerald Belton)  writes

>Subject: Need to find out numb
>Date: 20 Apr 93 12:18:00 GMT

>AL>There is a number you can call which will return a synthesized
>AL>voice telling you the number of the line.  Unfortunately, for the
>AL>life of me I can't remember what it is. The telephone technicians
>AL>use it all the time.  We used to play around with this in our
>AL>dorm rooms since there were multiple phone lines running between
>AL>rooms.
>
>It probably wouldn't help for you to post the number, since it appears
>to be different in each area.  For what it's worth, in the New Orleans
>area the number is 998-877-6655 (easy to remember, what?)
>
>
> * SLMR 2.1 * Ask me anything: if I don't know, I'll make up something.
>                                          

Here in our city, dialing either 940-7222 (newer exchanges) or 940-2222222 [
sic] will get a synthesized message. Works great for having people call you 
back at unlabeled pay phones.

Regards,
Bill


+------------------------------------+-----------------------------------+
| Ronald W. (Bill) Butts, Jr.        |      Gentlemen! Gentlemen!        |
| Electrical Engineering Department  |    You can't fight in here--      |
| The Wichita State University       |       This is the War Room!       |
| butts@shocker.ee.twsu.edu          |                                   |
+------------------------------------+-----------------------------------+

Newsgroup: sci.electronics
Document_id: 54058
From: msunde01@mik.uky.edu (Mark  Underwood)
Subject: Re: How to the disks copy protected.

In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
(Eric Richard Noel) writes:
> I hate hard copy manuals, and would rather have all docs online - *not*
> because I want to copy the program, but because its usually faster and
> and convenient than sifting through an old book I can't find.

Just MHO, but I prefer hardcopy books because you can have three or four  
of them open spread across the bed (next to the desk in my dorm) and  
reference them while using the program full-screen.  The Windows Help  
things come closest to good on-line documentation I've seen, but they  
generally aren't detailed enough and would probably take a LARGE amount of  
space (even compressed) which is at a premium on my system . . ..  In  
fact, the manuals are the primary reason I bought Borland's C++ compiler  
instead of using the one the lab licensed (in the lab, of course).  I've  
got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
his own . . . :-)

> 
> Off deeper end-> Why does everyone think they need to be able to make a 
> backup copy? Almost all new software must be installed to the hard disk,
> so you are left with the originals as your backups. I think its a waste
> of time, space, and money, as well as it makes it to tempting to "lend"
> out the backups. 

We've destroyed about six sets of original Microsoft Word for Mac 5.0 and  
Word for Windows (may have been a bad batch of disks).  Don't have the  
faintest idea what happened to them, they just went bad.  Weren't stored  
near any magnetic fields or otherwise mistreated, indeed they were only  
used once.  Given this, and the massive headaches finding a working set of  
disks to fix some of the machines that periodically go down, I'd say  
having working backups is a godsend.  I sure wish we'd had them (Sometimes  
I think Murphy's Law holds true more often than Newton's!!) when we needed  
them.  I think it's sortof like snake antivenin.  99.995% of the time you  
have absolutely no use for it, but when you need it, BOY do you ever need  
it!

I don't have backups of my originals at "home" but then my machine doesn't  
see anywhere NEAR the use/abuse of these here at the lab, and so I  
consider it less of a risk.  Still, I usually make "working copies" of  
them when I install them and then eventually re-use these "working copies"  
for something else. . ..


> 
> 
> No flames intended - just my thoughts.

Just mine, too!  :-)

BTW, before anyone notices my mentioning "copying" programs from machine  
to machine when we do installs here and wonders about the licensing, the  
upper-management (non-student staff, of course) are METICULOUS in checking  
with providers of the software and making SURE we are sticking to the  
license agreements . . ..

Mark S. Underwood
EE Student, University of Kentucky
Lab Assistant, Boyd Hall Microlab 
	(a tiny little division of UK Library Microlabs)
E-Mail:  msunde01@mik.uky.edu

Newsgroup: sci.electronics
Document_id: 54060
From: acollins@uclink.berkeley.edu (Andy Collins)
Subject: Re: Packet Radio on the PC

In article <regmad.735519580@gsusgi1.gsu.edu> regmad@gsusgi2.gsu.edu (Michael de Kraker) writes:
>koberg@spot.Colorado.EDU (Allen Koberg) writes:
>
>>I'm looking for any and all information regarding packet radio
>>implementation on the PC.  Software, hardware, whatever.
>
>    /        /        /       /    Michael A. de Kraker
[ Question about packet radio deleted ]
>
>   /        /______  /       /     Georgia State University  404-651-2390

How about rec.radio.amateur.packet?  At least at my site, there is no
general packet radio (i.e. non-amateur) newsgroup.

That said, I would definately subscribe to r.r.a.packet if you want to
learn about all aspects of amateur packet radio, at both the high and
low ends.  Also, I would get the FAQ from the group, and then post any
specific questions to that group.  Everything I could tell you is 
probably in the FAQ, and the people who really know what's going on all
seem to be on r.r.a.packet (although they might be here too, you never know :)

Hope it helps...

Andy Collins, KC6YEY
acollins@uclink.berkeley.edu

Newsgroup: sci.electronics
Document_id: 54061
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Radio Electronics Free information card

In article <C5uLqG.I5@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
>
>	How does the radio Electronics free information cards work.
>Do they just send you some general information about the companies that
>advertise in their magazine or does it also give you sign you up for a
>catalog. 

Radio-Electronics sends each company a bunch of computer-printed address
labels for all the people who circled that company's number.

The company sends whatever it wants to -- normally a catalog.


-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 54062
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.

This topic was beaten to death a year or so ago.

The concrete is not the problem. 

Lead-acid batteries often fail from disuse (not being charged for a long
time), but there's no way the concrete floor could be the cause of the
problem.

-- 
:-  Michael A. Covington, Associate Research Scientist        :    *****
:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
:-  The University of Georgia              phone 706 542-0358 :   *  *  *
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><

Newsgroup: sci.electronics
Document_id: 54063
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <1r7h1r$o7p@uniwa.uwa.edu.au> ascott@tartarus.uwa.edu.au (Andrew Scott) writes:
>I would expect that CD-ROM software would not even need copy protection.
>As the program on a CD-ROM would not fit onto a hard-drive, and it is
>impossible for the average (and even not-so-average) user to write to a
>CD-ROM, copies of the software (that still work) could never be made.
>
>Hmmm.. now that I think about it.. with a creative TSR, maybe
>disk-swapping could be used to simulate files on a single disk. You
>would need a tonne of disks though.
>
There are many programs on CD-ROM that fit on a harddisk, not all software 
is that big (but we're getting there :-)).

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only ones.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54064
From: john@gu.uwa.edu.au (John West)
Subject: Re: ATARI 2600 Processors

ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:

>In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>>game machine). 

>Wrong, it has a 6507.

For those who would like to know, the 6507 was a 6502 without IRQ or NMI,
and with only 13 address lines (giving 8K memory space).

>It had one custome chip (not an ASIC in the sense that word is now understood):
>the TIA (sometimes known as the 6526, although most other manufacturers list
>that as the CIA complex interface adapter.)  TIA stands for Television
>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>the 2600 possessed.

Didn't know about it being called the 6526 - thats the CIA found in the
Commodore 64 (I don't believe this chip existed when the 2600 was around).
The TIA was mapped into the bottom 128 bytes of page 0, and shadowed in the
bottom 128 bytes of page 1. To get an image on the screen, you had to wait
until the raster line your picture started at, load bitmaps for this line
into the 'sprite' registers, tell them what x positions to take, how many
duplicates you wanted, etc, then do it all again for the next line. This
took all of the processor's time during the visible portion of the
display.

>There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
>regulator and (if memory serves) a 555 timer.  That's all.

The RAM was mapped into the top 128 bytes of page 0, and shadowed in page
1. The 6502 has a zero-page addressing mode on most instructions that is
both shorter and faster than the normal ones, so it is important on a
machine like this to have the scratchpad RAM in page 0. Unfortunately, it
also wants its stack to be in page 1 (the stack pointer is 8 bits, and the
high byte of the address is hardwired to 1).

The IOT section was mapped into page 2 somewhere. 2 8 bit I/O registers
(can't remember if each bit could be independantly set to I or O like the
6522 and 6526), and 1(?) 8(?) bit timer with a programmable prescaler (I
think this was some power of 2). There were no interrupts in the system, so
many games would set up the timer at some known time, go away and do
something else for a while, then sit and wait for the timer to run down.

There was no logic in the box to do address decoding - the RIOT had at
least 2 chip select pins (probably one active high, one active low), and I
imagine the TIA was much the same. Various address lines were fed directly
to chip selects. The 6507 likes to have ROM right at the top of memory, so
the 2600 had to use ROMs with active high chip selects - not exactly
normal, so some cartriges had a 7404 in them to convert this to the more
usual active low chip select.

John West

Newsgroup: sci.electronics
Document_id: 54065
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

[byteocide]

>
>What I believe the companies should do is implement the above plus
>a special patch once the user registers that loudly exclaims upon bootup
>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>makes it more traceable, because if the patch's registration message is
>encrypted, it will be quite hard to change, and therefore provides a
>stable trail of who allowed their copy out of their hands, and thus
>violated their license agreement.
>
You take two copies with a different registration id, compare them byte for 
byte and you know where they are located. Usually you will be able to 
find out what is what after that. 

And what keeps me form registering as John Doe from the company Public 
Domain, Yellow Brick Road 1, Tinseltown or something???

>
>--Kasey Chang

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only ones.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54066
From: sl@nessie.mcc.ac.uk (Stuart Lea)
Subject: Anyone build anything interesting with PIC16C5X devices ?


I've just started programming with the PIC16c57 and I'd like talk to similar
like minded people ?  Have you built anything interesting, if so, I'd be
interested in talking about various aspects.

Yes, I already have the application sheets, assembler & simulator.

Cheers,

Stuart

-- 
+-Stuart Lea--Tel:061 200 4809--Fax:061 200 4019---UMIST University-----------+
| JANET   :   sl@uk.ac.mcc.nessie                  B22, Main Bldg., PO Box 88 |
| INTERNET:   sl@nessie.mcc.ac.uk                  Manchester, UK M60 1QD     |
+-----------------"Weather is here, wish you were beautiful"------------------+

Newsgroup: sci.electronics
Document_id: 54067
From: ws2@cunixa.cc.columbia.edu (Wayne Sun)
Subject: Looking for NC1 Telecaption Decoder Module

Does any one know where I can get a telecaption decoder module?

Need it to build a close caption decoder.
Thanks.

Wayne


'Wait till finals are over, that is when the fun really begins.'
'Enjoy the sun while its still young and out there.'
'When one dreams of his home town, he is not wishing that everything could
be as it was, but he wishes that he was still young to enjoy it all again.'

Newsgroup: sci.electronics
Document_id: 54068
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Subject: Re: Making up odd resistor values required by filters

idh@nessie.mcc.ac.uk (Ian Hawkins) writes:

>When constructing active filters,  odd values of resistor are often required 
>(i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
>capacitor values and cope with the strange resistances then demanded).

>Is there a PD program out there that will work out how best to make up such
>a resistance, given fixed resistors of the standard 12 values per decade?.(1,
>1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
>recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
>q and finding prefered values x,y and z.

I once wrote such a program (in BBC basic...) It was very crude, and took
around 5 seconds to do an exhaustive search (with a small amount of 
intelligence), and told you the best combination >Rq and the best below Rq.

If you want to write one, just store the prefered values in an array, and
then search the solution space using three nested loops. I'm sure you
could knock this up in an hour.

Christopher
--
 ==============================================================================
  Christopher Hicks    |      Paradise is a Linear Gaussian World
  cmh@uk.ac.cam.eng    |    (also reported to taste hot and sweaty)
 ==============================================================================

Newsgroup: sci.electronics
Document_id: 54069
From: kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,)
Subject: Why circuit boards are green?

Not that the question is anything important, but I am still curious:
Why is that almost all printed circuit boards are green? I have seen
a few blue ones, but no red, yellow, company logo etc. Is there a
technical reason or could it be that the marketing "geniuses" have
not tought about it (yet)?
--
Juha

Newsgroup: sci.electronics
Document_id: 54070
Subject: PCMCIA
From: martin.vuille@synapse.org (Martin Vuille)

Newsgroup: sci.electronics
From: martin.vuille@synapse.org
Subject: PCMCIA

Does anyone know who to contact to obtain a copy of the PCMCIA standard?

Thanks
MV
---
  OLX 2.1 TD  ProControl * Kemptville, ON * 04-22-93 9:34 pm

Newsgroup: sci.electronics
Document_id: 54071
Subject: ELECTRONIC DESIGN MAG.
From: martin.vuille@synapse.org (Martin Vuille)

Newsgroup: sci.electronics
From: martin.vuille@synapse.org
Subject: Electronic Design

Does anyone know the telephone number for the circulation department
of 'Electronic Design' magazine?

MV
---
  OLX 2.1 TD  ProControl * Kemptville, ON * 04-22-93 9:35 pm

Newsgroup: sci.electronics
Document_id: 54072
From: stephen@dogmatix.inmos.co.uk (Stephen Collyer)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr22.220549.26828@dmu.ac.uk>, cph@dmu.ac.uk (Chris Hand) writes:
|> Carter Ames (camter28@astro.ocis.temple.edu) wrote:
|> :   Why does a lead acid battery discharge and become dead (totally unuseable)
|> : when stored on a concrete floor?  

I think it's because the lead gets coated with lead oxide if the battery is
not being charged or discharged. I remember some advice from an ancient car
manual guide my father had, which was to use car batteries to power a garage
clock or something similar when they're not in a car. This is supposed to 
prevent the oxidation but I've no idea if it really works. The concrete floor
connection is a red herring.

|> 
|> It could be that you stored it somewhere that it could become covered
|> by moisture or damp air, which would short out the terminals.

This may contribute to discharging but would be reversible.
 
|> 
|> The same thing happens to my car (Citroen 2CV) -- damp gets under the
|> bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.
|> 
|> The solution (for the car) is to clean the plug leads and spray with
|> WD-40 (moisture repellant).  If damp *is* the problem, then storing the 

Well, this is off-topic, but back in the days when I used to drive bangers
I never found WD-40 to do anything that wiping with a dry cloth did'nt do.
I think the effectiveness of WD-40 is a myth invented by the guy who owns
the company.

|> battery off the ground may help.  I'm not sure if spraying with WD-40
|> would be safe since it is very flammable (high percentage petroleum).
|> 
|> Just a thought...
|> 
|> Chris
|> 
|> -- 

Steve Collyer.

Newsgroup: sci.electronics
Document_id: 54073
From: pjhicks@acri.fr (Peter J. Hicks)
Subject: Re: Lead Acid batteries & Concrete?

In article 3nx@athena.cs.uga.edu, mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>>
>>  Why does a lead acid battery discharge and become dead (totally unuseable)
>>when stored on a concrete floor?  
>>  I decided to bring the battery in from the lawn mower and the motorcycle
>>from the unheated garage this year, *to preserve them* and I just
>>went to use them and noticed that not only do they not work, but 
>>they act like the two terminals are shorted.  I asked a friend
>>and he said that you should never do that, 'cause it ruins them,
>>but he couldn't tell me why.
>
>This topic was beaten to death a year or so ago.

It seems to me that the original question was for advice on his problem
not a history lesson - I think that  if this question comes up from time
to time then people should get a civil answer 


>

>The concrete is not the problem. 
>
>Lead-acid batteries often fail from disuse (not being charged for a long
>time), but there's no way the concrete floor could be the cause of the
>problem.

Could ANYONE please explain WHAT happens with a battery and is there any
cure to get it back into life
  
>


>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><





Newsgroup: sci.electronics
Document_id: 54074
From: ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar)
Subject: Re: ATARI 2600 Processors

In article <1r847f$kp7@uniwa.uwa.edu.au> john@gu.uwa.edu.au (John West) writes:
>ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:
>>Wrong, it has a 6507.

>For those who would like to know, the 6507 was a 6502 without IRQ or NMI,
>and with only 13 address lines (giving 8K memory space).

Yes, but still not a 6502 for those differences.  Same instruction set,
of course.

>>It had one custom chip (not an ASIC in the sense that word is now understood):
>>the TIA (sometimes known as the 6526, although most other manufacturers list
>>that as the CIA complex interface adapter.)  TIA stands for Television
>>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>>the 2600 possessed.

>Didn't know about it being called the 6526 - thats the CIA found in the
>Commodore 64 (I don't believe this chip existed when the 2600 was around).

Yes, the same number, but an entirely different device.  I should have
qualified this further by stating that this was the PAL version of the TIA -
I am not 100% sure that the NTSC TIA would have a different number.

>The TIA was mapped into the bottom 128 bytes of page 0, and shadowed in the
>bottom 128 bytes of page 1. To get an image on the screen, you had to wait
>until the raster line your picture started at, load bitmaps for this line
>into the 'sprite' registers, tell them what x positions to take, how many
>duplicates you wanted, etc, then do it all again for the next line. This
>took all of the processor's time during the visible portion of the
>display.

Does anyone on the net actually have details of the TIA, as this is the only
device I have not yet discovered details about?  Atari Australia, when asked,
claimed that their attempts to get the programmers documentation for the 2600
had failed, as the US head office had refused to provide it.

>to chip selects. The 6507 likes to have ROM right at the top of memory, so
>the 2600 had to use ROMs with active high chip selects - not exactly
>normal, so some cartriges had a 7404 in them to convert this to the more
>usual active low chip select.

I saw a couple of cheaper devices with PN2222's and a couple of resistors
hooked up as a cheap inverter.  Nasty, but workable, and cheaper than a
7404 inverter if labor costs almost nothing.

							Ian.

Newsgroup: sci.electronics
Document_id: 54075
From: thor@e.kth.se
Subject: Looking for Z80-STI (MK3801) by Mostek

Hi,
I am looking an integrated circuits for my Z80-based 
computer.
The circuit is called Z80-STI (Serial Timer Interrupt), 
MK3801, and
made by Mostek. Mostek is called SGS Thompson today.
 
I have been in contact with SGS Thompson, unfortunately 
they me told that Z80-STI is obsolete.
 
So, my question is if anyone know if I can get hold of that 
circuits. Are there any companies that specialize in selling 
circuits that are no longer in production? I have contacted 
several electronic brokers in
Sweden, but without any success. I would appreciate if you 
could give me hint where I should continue looking. Even 
companies in the United States would be fine, since this 
circuit is pretty crucial to me.
 
 
Thanks in advance.
 
 
Thomas Thor
Royal Institute of Technology
Stockholm, Sweden


Newsgroup: sci.electronics
Document_id: 54076
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: help me, i'm not clever! (how to make power supply?)

In article <94318@hydra.gatech.EDU> gt4417a@prism.gatech.EDU (SKELTON,JOEL PHILLIP) writes:

>I need to make a power supply that can take input from a 
>cigarette lighter in a car (12v dc) and drive 7.5 volts
>at up to 3.0 amps. I know enough to know that a simple
>voltage divider with two resistors won't do it right. Can
>such a thing be made from Radio-Shack-able parts without
>too much difficulty?

>jps
>bf

>p.s. I've looked for premade things like this at radio shack but
>none of it seems to go any higher than about 800mA.


>-- 
>Joel Skelton   --    North Avenue Trade School, Dept. of Round Things
>gt4417a@prism.gatech.edu   (ask for Scooter Technologies, and receive)

See if Radio Shack has a National Semiconductor Adjustable Voltage 
Regulator, (National) part number: LM350T or LM350K.  These devices are 
rated for an input to output differential of up to 35 Volts @ 3 Amps.

Digi-Key Corp. has these parts, as well as several other useful regulators.
If you don't have their catalog, their phone number is: 1-800-344-4539.

I can only guess that you may intend to recharge a 7.5 VDC nicad battery 
with this device, and if I'm right, you may want to look through some of the 
hobbiest books to get various ideas for battery charging circuits, first.

If you get stuck, e-mail me your FAX number, if you have one, and I'll send 
you some suggestions or schematics.

e-mail: willisw@coe-nw.clemson.edu



Newsgroup: sci.electronics
Document_id: 54077
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: How to the disks copy protected.

In article <C5x75A.48H@ms.uky.edu> msunde01@mik.uky.edu writes:
>In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
>(Eric Richard Noel) writes:
>> I hate hard copy manuals, and would rather have all docs online - *not*
>> because I want to copy the program, but because its usually faster and
>> and convenient than sifting through an old book I can't find.
>
>Just MHO, but I prefer hardcopy books because you can have three or four  
>of them open spread across the bed (next to the desk in my dorm) and  
>reference them while using the program full-screen.  The Windows Help  
>things come closest to good on-line documentation I've seen, but they  
>generally aren't detailed enough and would probably take a LARGE amount of  
>space (even compressed) which is at a premium on my system . . ..  In  
>fact, the manuals are the primary reason I bought Borland's C++ compiler  
>instead of using the one the lab licensed (in the lab, of course).  I've  
>got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
>his own . . . :-)
>

Agree 100%, personally I cannot flip from page to page on a screen and
retain information as easily as in the written page.

>> 
>> Off deeper end-> Why does everyone think they need to be able to make a 
>> backup copy? Almost all new software must be installed to the hard disk,
>> so you are left with the originals as your backups. I think its a waste
>> of time, space, and money, as well as it makes it to tempting to "lend"
>> out the backups. 
>
>We've destroyed about six sets of original Microsoft Word for Mac 5.0 and  
>Word for Windows (may have been a bad batch of disks).  Don't have the  
>faintest idea what happened to them, they just went bad.  Weren't stored  
>near any magnetic fields or otherwise mistreated, indeed they were only  
>used once.  Given this, and the massive headaches finding a working set of  
>disks to fix some of the machines that periodically go down, I'd say  
>having working backups is a godsend.  I sure wish we'd had them (Sometimes  
>I think Murphy's Law holds true more often than Newton's!!) when we needed  
>them.  I think it's sortof like snake antivenin.  99.995% of the time you  
>have absolutely no use for it, but when you need it, BOY do you ever need  
>it!
>

Ditto's ... in fact .. at work, where things are dead if the backup
is no good, I insist on having at least a 2 level backup system.  
It seems that whenever you have 2 good backups, you never need them, 
but if you don't have them, Murphy guarantees that you'll suffer for it.

>I don't have backups of my originals at "home" but then my machine doesn't  
>see anywhere NEAR the use/abuse of these here at the lab, and so I  
>consider it less of a risk.  Still, I usually make "working copies" of  
>them when I install them and then eventually re-use these "working copies"  
>for something else. . ..
>
>
>> 
>> 
>> No flames intended - just my thoughts.
>
>Just mine, too!  :-)
>

 and mine of course.

Richard Dell

Newsgroup: sci.electronics
Document_id: 54078
From: sasrer@unx.sas.com (Rodney Radford)
Subject: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

stephen@dogmatix.inmos.co.uk (Stephen Collyer) writes:
>|> The same thing happens to my car (Citroen 2CV) -- damp gets under the
>|> bonnet (US: "hood") and shorts the spark-plugs to earth so it won't start.
>|> 
>|> The solution (for the car) is to clean the plug leads and spray with
>|> WD-40 (moisture repellant).  If damp *is* the problem, then storing the 

>Well, this is off-topic, but back in the days when I used to drive bangers
>I never found WD-40 to do anything that wiping with a dry cloth did'nt do.
>I think the effectiveness of WD-40 is a myth invented by the guy who owns
>the company.

Back in high school I used to work for a detailing company, and one of the
services we offered was an engine cleaning (remove all that oil BEFORE you
sell the car...  ;-}). Unfortunately, we did not have a high pressure
washer so we would use one several miles from the shop. On more than one
occasion after washing the engine, it would not start as water would have
gotten under the distributor (I would put a plastic bag around it to try and
minimize this), around the spark plug wires, etc and it would be nearly
IMPOSSIBLE to try and wipe all these areas down with a dry rag. The usual
solution was to carry a can of WD-40, and when the car wouldn't start to spray
all the likely areas and it would then start on the very first time.

It may be a myth, but it certainly kept me from being stranded at a car wash...

--
---
Rodney Radford          || Computer Graphics/Imaging
sasrer@unx.sas.com      || SAS Institute, Inc.
(919) 677-8000 x7703    || Cary, NC  27513


Newsgroup: sci.electronics
Document_id: 54079
From: mcole@spock (COLE)
Subject: microstepping

Does anyone know where to get a schematic for a micro stepping circuit?
Any help would be appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
Document_id: 54080
From: mcole@spock (COLE)
Subject: HM8350 or HM8348

I have some MICE that have a chip numbered HM8348 and HM8350.  I have not  
been able to find information on these.  Any help would be appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
Document_id: 54081
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Switching PS questions


	Greetings. I've recently decided to chuck the linear regulators
	and learn the "black magic" art of switching power supplies...
	(before anyone flames me, I KNOW, both have their place :-)

	Anyways, I've built the basic up & down converters with pretty
	good results (>80% efficiency) but I'm running into problems
	when I try to design & build anything that puts out serious
	amps... I know it can be done (I have some 5V@200A guts on my
	bench) but something puzzles me: I'm using a simple choke as 
	the storage element (basicly a toroid with a single winding)
	but ALL commercial models use transformers with MANY windings.
	I traced a few and they seem to use some of the winding for
	the usual error/feedback but some of the others seem to loose
	me... What are they for? Better than that, anyone have a full
	schematic for one of these that I could get a copy of? I'd
	love to see how they manage to squeeze out so much from such
	low volume :-)

	My other problems (in getting high amps & good efficiency) are
	1) Lack of sources of ideal components (calculated) and 2)
	Limited knowledge of the whole topic... I'm doing this on my
	own (not school) mind you (in fact, I have yet to take any
	course that covers transistors ;-)

	So, is the answer to #1 the accumulation of dead commercial
	models and truning into a scavanger (not that it's not what
	I'm doing now...) and #2 getting & understanding schematics
	and a bit more of the [mind-boggling] theory? 

	Take care.

	P.S. My goal is 12V @ ~25A in (car battery) -> 250VAC out and
	(on the other end) 250V -> +5VDC @ 5A, -5V @ 1A, +12VDC @8A
	and -12VDC @1A... the distance between the two will be
	more than 100 feet (of 14-16 gauge) but less than 300 feet.
	Would like to have a working model in a year or so... :-) 
	(Do I have a chance to make it?)
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
Document_id: 54082
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Lead Acid batteries & Concrete?

Michael Covington (mcovingt@aisun3.ai.uga.edu) wrote:

: This topic was beaten to death a year or so ago.

: The concrete is not the problem. 

: Lead-acid batteries often fail from disuse (not being charged for a long
: time), but there's no way the concrete floor could be the cause of the
: problem.

Ditto. The only remote, and I do say remote, possibility is that if the
ground was REAL cold (< -30F) the battery might freeze an split. But then
it would probably freeze anyway :-)

        Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
Document_id: 54083
From: derry@NeXTwork.Rose-Hulman.Edu (John Derry)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu>  
camter28@astro.ocis.temple.edu (Carter Ames) writes:
> 
>    I was just wondering one thing, actually two. ( I hope that this is  
the
> proper place to post this subject)
> 
>   Why does a lead acid battery discharge and become dead (totally  
unuseable)
> when stored on a concrete floor?  
>   I decided to bring the battery in from the lawn mower and the  
motorcycle
> from the unheated garage this year, *to preserve them* and I just
> went to use them and noticed that not only do they not work, but 
> they act like the two terminals are shorted.  I asked a friend
> and he said that you should never do that, 'cause it ruins them,
> but he couldn't tell me why.
> 
> thanks
> camter28@astro.ocis.temple.edu


What happens is that (I heard this discussed on "Northern Exposure") there  
is a molecular juxtaposition of the molecules in the battery and the  
molecules in the concrete.  This acts as an attractant to UFOs (actually  
their crew members) and they arrive at the scene of the battery/concrete  
combination.

Then they proceed to SUCK ALL THE ENERGY OUT OF THE BATTERIES!

Remedy:  Set the battery on a nonconcrete floor.

Jack

Newsgroup: sci.electronics
Document_id: 54084
From: simon@sco.COM (Simon Tooke)
Subject: CALLER-ID chip info requested

I just got caller-id (except Bell calls it "call display" and didn't know
what I was talking about when I asked for "caller-id").  I got the
cheapest display box I could find, and hope to convert it to serial out.

The chip used is an 18-pin DIP marked "CDT 14-285" and "1473 9220".
I presume the 9220 is the date.

I'm hoping somebody out there knows something about this chip, to save
me a very strange few hours hooked up to a scope, asking my friends to
call me again and again.

I'll post any interesting replies, and my experiences.

-simon tooke

simon@sco.com



Newsgroup: sci.electronics
Document_id: 54085
From: skelly@amiganet.chi.il.us (Sean Kelly)
Subject: Pin-out for 27C64??

 
 
     Does anyone know the pin-outs for the 27C512 EPROM??  I have bought
several of them, none of which has come with the pin-outs!  Any info would be
appreciated....

%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
%   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
%   Always looking for classic video games for the following systems:   %
%                                                                       %
%  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Newsgroup: sci.electronics
Document_id: 54086
From: skelly@amiganet.chi.il.us (Sean Kelly)
Subject: Question on addressing...

 
 
     I have a question about accessing certain addresses on a chip,
particulary a 27C512 EPROM.  Although I don't know that much about it, as I
understand it, there's a pin on the chip that, when voltage is applied, kicks
up the address.  The question is how do you determine how many bytes the
address is incremented by??  For example, if I have code I want to be
accessed at $2000 and also at say $4000 how do I move the address pointer to
those positions??  Thanks for any info...

%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
%   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
%   Always looking for classic video games for the following systems:   %
%                                                                       %
%  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Newsgroup: sci.electronics
Document_id: 54087
From: gfl@herahera.cc.bellcore.com (lenahan,grant f)
Subject: Re: Adcom cheap products?

Much deleted about assembly in USA vs. other, 
I wish to focus on the subject of warm-running amplifiers:

> : >  Sure the amp runs very fairly
> : >  hot - but that's how you get an amp to sound incredibly good.
> 
> : An amp that runs hot has no bearing on how it's gonna sound.
> : The amp you have probably is running Class-A the whole day.
> 
> : because either the engineer or manufacturer of that amp wanted
> : to skimp on heatsinking or cooling to save costs!  Hmmmmm....
> 

There is a correclation between warm-running amps and good sound,
or in your words, "it DOES have a bearing on....".

Now, I don't suggest that everyone run out and create combination
stove/amplifiers that will degrade lifespan,
but a cold-running circuit is much more suceptible to temperature
variation with varrying current than is a warm-running one.  And since
junction resistance is a function of temperature, this has a detrimental
effect on linearity.  

a few facts:
-bias points vary with temperature
-junction resist varrie with temp
-Adcom products do NOT run class-A

If you still don't beleive this assertion, consider the warm-up requirements
for most good test equipment, or better yet, just listen to an amplifier
warm-up.  On many designs its quite audible, on mine, about 20 minutes for
the output stage, many hours for the drivers.  Fortunately the drivers
are not switched.

In any experiment, or when drawing conclusions from listening,
betcareful to seperate the effect of device temperature from bias
(idle current) level.  Both have a positive correlation with low
distortion and "good" sound quality, and high bias results in
warmer operation, all other factors being equal.

Grant



Newsgroup: sci.electronics
Document_id: 54088
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Suggestions  on Audio relays ???

In article <C5qsBF.IEK@ms.uky.edu>, billq@ms.uky.edu (Billy Quinn) writes:
|> I built a little project using the radio shack 5vdc relays to switch
|> audio.  I got pretty bad 'clicks' when the thing switched.  I was doing
|> most of the common things one is supposed to do when using relays and
|> nothing seemed to get rid of the clicks.
|> 
|> My question is:
|> 
|> 	Is there a good relay/relay circuit that I can use for switching
|> audio, so that there will be *NO* noise of any kind on the audio lines.
|> 
|> I will appreciate any advice or references to advice.  Also, exact part
|> numbers/company names etc. for the relays will help!

The first step is to make sure that there is no DC component, intentional
or not, on the audio lines to be switched. If neither the output or
input presents an unintentional DC level (let's say they're capacitively
coupled), then putting a 22 K resistor from each input to ground, and
from the output to ground is a good precaution against leakage in any
coupling caps presenting a DC level that is GUARANTEED to cause a click.

If the device presents an unintentional DC level that is from more than
just coupling capacitor leakage, then you need to remove the DC before
switching with coupling capacitors of your own.

If you have more than one relay (each relay switching one input
through to a common output), you can use make-before-break switching
where for a brief instant both sources are connected during a switch
change. This may mask the switch click.

An audio switch that is clickless is made by taking a light bulb and
making your own ersatz opto-isolator with a light-dependent resistor (LDR)
sealed inside a piece of black heatshrink. Many broadcast consoles
use this older, but time-honored technique. Claro actually makes
a complete optisolator like this, but I don't have a part number handy.
Radio Shack has a LDR grab-bag (276-1657) you might want to try.

For a simple, solid state clickless switch that is cheap, you might try 
looking at the CD4066 analog switch that is commonly available (or its
older predecessor, the 4016). Again, the DC component must be removed
prior to switching. Other alternatives include JFET switches (both discrete
and IC) and diode switching (which works relatively well, surprisingly).
All the above, with their pitfalls and application tips could easily
make a subject for a multi-page article.

Solid state switches may induce a click of their own when turned on
due to charge being injected into the audio line through device
capacitance when the control signal changes state. Techniques to
minimize this include lowering the impedance of the signal paths through
the switch, differential switching, and slowing the risetime of the
control pulse. With the 4016, cutting the click can be as simple as
putting 10K - 47K resistors in series with the control pins.

Hope this helps at least get you started.

-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 54089
Subject: Re: How to the disks copy protected.
From: sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen)

Kuo-Sheng (Kasey) Chang (kschang@sfsuvax1.sfsu.edu) wrote:
> The program is definitely backupable, if restored to the same machine (depends
> on the programmer...  don't use a disk drive characteristic!)  If the user 
> did an upgrade to the machine, he/she should reinstall all programs any way.
> No document look-up, no disk wear-and-tear!

	This is not a good idea.. I upgraded my motherboard last fall.  I
would have been quite pissed at any software that would have forced me to
reinstall simply because I changed motherboards.

	Any info in the BIOS is too volatile to use as a checksum.  Are you
going to require that a user re-install all their software if they add 4Mb
of RAM to their computer?  I did that a couple of weeks ago.  It's in the
BIOS, and if software had told me "this isn't the machine you installed me
on" I would never have used that software again.  Really bad idea.

> I did not say that the originals would allow only one install.  The user's 
> conscience should do that.

	This is silly.  It's much easier to loan disks to a friend and let
them do an install than to backup your copy already on disk, and then give
them that.  Your scheme isn't going to stop anyone.

> You know how many bytes you need to change in X-wing to disable
> the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)

	Do you know any assembly language at all?  All anyone needs to do if
find the part of the code that does the quiz, and insert a JMP instruction
to just completely skip it.  Not that difficult, really!  And there is very
little that commpanies can do to stop this type of thing.  Using PKLITE or
some similar utility would help, but only if the resulting compressed .EXE
were tagged as uncompressable.

> What I believe the companies should do is implement the above plus
> a special patch once the user registers that loudly exclaims upon bootup
> "REGISTERED TO XXXXX -- address, city, state zip" and disables the above.

	This is by far the best idea you presented in your post.  Making it
plainly obvious who registered is going to stop casual pirates. But, the
determined ones are just going to answer "Joe Blow" to the question of
"what's your name" so this won't stop them in the long run.

	Pirates are always going to win this fight.  They simply have more
time to work on the software and figure out the protection scheme.

--
Steve Madsen
sjmadsen@nextsrv.cas.muohio.edu

Ask me about Linux, the free 386 unix!

Newsgroup: sci.electronics
Document_id: 54090
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <rcstage1.128.735548462@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:
>In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>[byteocide]

>>What I believe the companies should do is implement the above plus
>>a special patch once the user registers that loudly exclaims upon bootup
>>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>>makes it more traceable, because if the patch's registration message is
>>encrypted, it will be quite hard to change, and therefore provides a
>>stable trail of who allowed their copy out of their hands, and thus
>>violated their license agreement.
>>
>You take two copies with a different registration id, compare them byte for 
>byte and you know where they are located. Usually you will be able to 
>find out what is what after that. 

Probably, but the point is THE COMPANY make the registration patch, NOT
YOU.  Sure, you can probably find another registerred user and compare notes,
but WHY?  It's not hindering you in any way unless you are just hacking.
[Problem about people who cut TOO MUCH from quoting...]

>And what keeps me form registering as John Doe from the company Public 
>Domain, Yellow Brick Road 1, Tinseltown or something???

Nothing, but if you read my WHOLE suggestion, I'm saying that you register
via MAIL by mailing in your registration card, THEN the company send you
the patch which includes the info you put on the registration card.

--Kasey Chang

Newsgroup: sci.electronics
Document_id: 54091
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Need help with video detection circuit

verity@jack.sns.com (Steve Verity) writes:

> 
> 
> I am trying to build a circuit that detects the presence of video (Vs.
> a blank screen) by monitoring the R,G, and B outputs of a graphics
> card.  It should be able to detect the presence of a single pixel at
> 65 MHz, which would mean detecting a 15 NS pulse.  It should also be
> able to tell the difference between a blank screen (about 300 mv)
> and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
> cheap.  
> 
> My first circuit was a dismal failure.  I used 3 compariators; each
> compariator had the + input going to one of the guns, the - input
> went to a reference created by a voltage divider(a potentiometer).
> 
> The first problem was that the compariator was way too slow.. I
> needed to get several pixels in a row before it would fire the
> compariators, so I could have a whole screen full of text, but my
> 
> The second problem is that there was more noise on the reference then
> the smallest difference between a blank screen and a dim screen.  In
> fact the difference between completely black and completely white is
> only 650 mv.  I am wondering if I am going to have to amplify the
> video signals to make this work.  
> 
> There are faster compariators, but they are expensive, and require 
> split supplies.   I would need to replace my .49 quad compariator
> with three 1.89 compariators, and create a whole new power supply
> circuit.  
> 
> At this point, I think what I need is some sort of transistor
> circuit.  Transistors are fast and cheap and should do the trick...
> 
> Unfortunately, I am way out of my league when It comes to designing
> transistor circuits, so I am appealing to the net for help.  Any
> ideas, tips, circuits, pointers, references, etc. would be greatly
> appreciated.  
> 
> Oh yes, I only sample the output of this thing every second or so, so
> I don't need a fast response time at all, however, I haven't found a
> way to take advantage of that fact.
> 
> Thanks a lot for any help anybody might be able to give. Of course,
> you will have my undying gratitude.
> 
> 
> Steve Verity
> 
> 
> 
> 
> -- 
> ..........>.........>........>......>...>...>..>..>..>..>.>.>.>>>>>>>>+ .   
> Steve Verity                  +   +             ...Maxed on MIDI        + .
>                                     +      verity@jack.sns.com      + ..   +

IN ORDER to get the 15 nS response time you need, you are better off 
going to an ECL slicer which can run off a single +5 or -5.2 V supply, 
you just need to bias or do some level shifting perhaps to get it in the 
range. Check out the ECL 10K books for a simple cheap solution.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54092
From: gcarter@infoserv.com (George Carter)
Subject: Re: Does someone know what is the news group for IEEE.

In <1993Apr19.192953.22874@usl.edu> yxy4145@ucs.usl.edu (Yu Yingbin) writes:
>       yxy4145@usl.edu     Thanks a lot.

ieee.general

and

ieee.announce


are the most frequently used groups.

Newsgroup: sci.electronics
Document_id: 54093
From: UC532838@mizzou1.missouri.edu (handy)
Subject: info wanted about standard phone line

greetings..
I'm a novice in this area. I'm trying to gather info. on standard
phone line settings.
quick questions :
      > if I just want to send out a beep over the phone lines,
        can I do it with some function generator & tie it up to
        one of those phone wires ??
      > which one of those wires should I connect to my DTMF chip
        as AUDIO IN ??
 
any help would be much appreciated..
 
Thankx in advance - Handy Trisakti
                    uc532838@mizzou1.missouri.edu

Newsgroup: sci.electronics
Document_id: 54094
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Voltage regulation and current limiting

acollins@uclink.berkeley.edu (Andy Collins) writes:

> One not-so-quick question to throw out there for you guys...
> 
> For our class project, we need to design and build a power supply
> to the following specs:
> 
> Voltatge:  adjustable from 1-12V
> Current:   *limited* at 1A
> 
> Voltage must stay within 2% of designated value for I from 0-1A
> AC ripple less than 5 mV (rms)
> 
> Of course, we can't just use an adjustable voltage, current-limiting
> regulator chip ;^)
> 
> Our problem is with the current limiting (i.e. we've found stuff to
> do the rest of the parts of the circuit).  What the supply must do,
> if presented with a load which would draw more than 1A, given the
> supply voltage, is reduce the voltage so that the current will equal
> one amp.  Thus, if we were to short the thing with the ammeter, we
> should read one amp.  If we measure the current through a 1 ohm 
> resistor at 12V, we should read one amp (and the output voltage, by
> necessity, must be 1V.
> 
> The only basic idea we have seen for the current limiter involves
> a circuit which will pull current off of the base of the output 
> power transistor, and therefore reduce the output.
> 
> So, does anybody have any ideas we could work from?
> 
> Thanks in advance.
> 
> Andy Collins, KC6YEY
> acollins@uclink.berkeley.edu
> 
> ps: If anybody wants to flame this as a stupid project, I agree fully,
>     but I still have to do it, its graded ;^)
> 

You can design for ramp shutoff, brick-wall current limit or even 
fold-back cutoff....sounds like you want "BRICK-WALL" current limit.

Your lead is correct to pull down the bias to the series regulator base 
drive. In order to get the brick -wall, you need enough voltage gain on 
the current sensor.  Normally a darlington on the current sensing 
resistor will be adequate, but for infinite gain.. use an op amp to sense 
the current releative to a stable voltage reference and use a driver to 
turn off the base bias on the series-pass transistor.  Phase compensation 
may be necessary with this closed loop control system if yopu have more 
than 180 degrees phase shift in your feedabck circuit at unity gain OK??

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54095
From: dino@inqmind.bison.mb.ca (Tony stewart)
Subject: Re: Making up odd resistor values required by filters

idh@nessie.mcc.ac.uk (Ian Hawkins) writes:

> When constructing active filters,  odd values of resistor are often required 
> (i.e. something like a 3.14 K Ohm resistor).(It seems best to choose common 
> capacitor values and cope with the strange resistances then demanded).
> 
> Is there a PD program out there that will work out how best to make up such
> a resistance, given fixed resistors of the standard 12 values per decade?.(1,
> 1.2,1.5,1.8,2.2,3.3 etc ).  It is a common enough problem,  yet I cant 
> recall seing a program that tells that Rx+Ry//Rz gives Rq,  starting with 
> q and finding prefered values x,y and z.
> 
> 
> 			Cheers
> 				Ian H  
> 

WHen trying to choose a resistor with a tolerance better than 1%, you 
need a trimmer or to screen devices, it can't be made from adding 2 
resitors of 1% value in parallel, since the smaller device will have the 
error of 1% to cope with. 
You have 3 choices;
a) live with the error of 1% tolerance devices for low Q circuits or low 
sensitivity designs
b) buy resistors with better than 1% tolerance (Vishay/Dale)
c) use trimmers or SOT's (Select-On-Test)

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54096
From: baden@inqmind.bison.mb.ca (Baden de Bari)
Subject: Blue LED's

 
        So what's the story here... we're all stuck with the regular
green, red, and off yellow-orange LED's!?  What gives!!??
        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???

                        ... just out of curiosity, of course ...
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

baden@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54097
From: dtmedin@catbyte.b30.ingr.com (Dave Medin)
Subject: Tran tube

I've got a 4PR1000A (EIMAC) unused transmitter tube for sale. Best offer
so far is $125. That's getting close to what I'll sell it for.
Hamfest prices have been about $200 - $250. It works, guaranteed.
Original packaging.
-- 
--------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    SSD--Networking				(205) 837-1174 (h)
    Intergraph Corp.
       M/S GD3004 		Internet: dtmedin@catbyte.b30.ingr.com
  Huntsville, AL 35894		UUCP:  ...uunet!ingr!b30!catbyte!dtmedin

 * The opinions expressed here are mine (or those of my machine)

Newsgroup: sci.electronics
Document_id: 54098
From: alany@tekig5.pen.tek.com (Alan Yelvington)
Subject: Re: Lead Acid batteries & Concrete?

The battery goes dead primarily becaust the floor is cold.  The temperature
combined with self-discharge promotes sulfation which ruins the plates of 
the battery.  I strongly suspect that the only reason the battery doesn't
go dead as quickly on a dirt surface is because cement tends to be quite
cooler.


Newsgroup: sci.electronics
Document_id: 54099
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Why circuit boards are green?

In article <1993Apr23.105152.20155@news.cs.tut.fi>, kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:
> Not that the question is anything important, but I am still curious:
> Why is that almost all printed circuit boards are green? I have seen
> a few blue ones, but no red, yellow, company logo etc. Is there a
> technical reason or could it be that the marketing "geniuses" have
> not tought about it (yet)?
> --
> Juha
The color of the board shows the composition of it, hence the use of it.

Original and older boards were bakelite composition, and were brown.
Phenolic (spelling) was a tan
Most "non filled" fiberglass boards used in computers are green.
Filled fiberglass is blue.
Teflon is white.

As boards evolved more and more demands were made of them.  First boards were
used mainly in audio circuitry.  Couldn't be used in high voltage or RF because
it would arc and burn.  Most boards today are fiberglass, the type being chosen
by its use and cost.  

Boards in satellite and microwave communication are teflon (and ceramic) as the
fiberglass, and other boards are conductive (they actually work more as a 
capacitive dialectric, but the word conductive simplifies explaination) at the
high frequencies.

Another printed circuit material used mainly in automotive and interconnections
is a thin flexible (mostly mylar) material and is used to connect the front of
the vehicle (etc) to the back instead of wiring harnesses.  Camcorders use this
to intereconnect the boards inside where wires would be a nuisance.

Am working on a generator made by Hewlet Packard right now and the entire board
is gold plated, boy it looks expensive!!!

Hope I got most of my facts right as I am working from memory of material read.

My education was pre-transister!
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
Document_id: 54100
From: wwerner@thor.mlb.semi.harris.com (William S. Werner)
Subject: Harris Semiconductor's AnswerFAX Information

     ====================================================
       H    H      A      RRRRR    RRRRR   IIIII  SSSS
       H    H     A A     R    R   R    R    I   S    
       HHHHHH    AAAAA    RRRRR    RRRRR     I    SSSS
       H    H   A     A   R    R   R    R    I        S 
       H    H  A       A  R     R  R     R IIIII  SSSS  
     ====================================================


Harris Semiconductor now has AnswerFAX. AnswerFAX is on-line 24 hours
a day, 7 days a week, so you can instantly receive datasheets and 
application notes by using your touch-tone telephone and FAX machine.
The number to call is (407) 724-3937. (It is not set up to do international
calls at this time.)

The general decision tree for the AnswerFAX is as follows, the numbers are
the available selections:


       Welcome to Harris Semiconductors AnswerFAX
                           |
        ----------------------------------------
        |                                      |
        1                                      2
        |                                      |
 Select 1 if you                        Select 2 for an
 are familiar with                      explanation of
 AnswerFAX.                             AnswerFAX
        |                                      |
        |--------------------------------------|
                           |
                           |                              
                           |
            --------------------------------
            |                              |
            1                              2
            |                              |
     Select 1 to order              Select 2 for a
     a document (the                list of catalogs:
     document list is                  1  New Products
     in the catalogs,                  2  Linear Products
     get them first)                   3  Data Acquisition Products
            |                          4  Digital Signal Processing Products
            |                          5  Discrete Power and Intelligent
            |                             Power Products
            |                          9  Application Notes
            |                              |
            |                              |
  Select appropriate document    Select Appropriate Catalog
            |                              |
            |                              |
  Do you want to order           Do you want to order
  anything else? If yes,         anything else? If yes,
  you will be taken back         you will be taken back 
  to the selection decision.     to the selection decision.
            |                              |
            |                              |
            --------------------------------
                          |
                          |
                          |
                  What is phone number
                    for your FAX?
                          |
                          |
                  What is your name?
               (request the instructions)
                          |
                          |
                         END                        



Bill Werner


===========================================================================
Bill Werner           WWERNER@hsscam.mis.semi.harris.com
Harris Semiconductor  wwerner@thor.mlb.semi.harris.com
Melbourne Florida     "....life is but a candle, and a 
(407)729-5515         dream will give it flame..." - Rush, Caress of Steel
===========================================================================
 


Newsgroup: sci.electronics
Document_id: 54101
From: ddexter@solaria.mil.wi.us (David Dexter)
Subject: MK3801 data needed

Hi
Could someone please send me enough info to talk to a MK3801? It's some
kind of multifunction peripheral chip made by Mostek I believe. Any help
would be GREATLY appreciated! Thanks in advance

Dave

-- 
============================================================================
ddexter@solaria.mil.wi.us                     technology thru broken parts
============================================================================

Newsgroup: sci.electronics
Document_id: 54102
From: theo@walt.caps.maine.edu (Theo M. Alpert)
Subject: Data Paging Info WANTED


 
 
    Hello, I'm looking for information on Alphanumeric pagers 
and *how* the data is sent from the paging transmitter and how 
I would go about building a device to decode the paging data 
(like my pager does) and feed it though an RS232 port.
    I'm planning on seperating different paging messages and 
different pagers in software to keep amount of hardware I need 
down....  Does anyone know what chips (Motorola?) are good for 
decoding Numeric and Alphanumeric paging data (and then stuffing
it down an RS232 port (basically any baud rate is fine!) ? 
    (I already have a radio reciever with headphone level 
output for the audio signal from the paging tower, but I'd be 
interested in anything you know about pagers, including the 
type of radio recievers they use!)
    Thanks in advance!            
-theo
EMAIL = theo@walt.caps.maine.edu

Newsgroup: sci.electronics
Document_id: 54103
From: segross@uci.edu (STEVE GROSS)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.171020.23982@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>In article <rcstage1.128.735548462@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:
>>In article <1993Apr22.163605.24784@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>>[byteocide]

>>>What I believe the companies should do is implement the above plus
>>>a special patch once the user registers that loudly exclaims upon bootup
>>>"REGISTERED TO XXXXX -- address, city, state zip" and disables the above.
>>>Two benefits: 1) encourages registration, 2) cuts down on pirating and
>>>makes it more traceable, because if the patch's registration message is
>>>encrypted, it will be quite hard to change, and therefore provides a
>>>stable trail of who allowed their copy out of their hands, and thus
>>>violated their license agreement.
>>>
>>You take two copies with a different registration id, compare them byte for 
>>byte and you know where they are located. Usually you will be able to 
>>find out what is what after that. 

>Probably, but the point is THE COMPANY make the registration patch, NOT
>YOU.  Sure, you can probably find another registerred user and compare notes,
>but WHY?  It's not hindering you in any way unless you are just hacking.
>[Problem about people who cut TOO MUCH from quoting...]

>>And what keeps me form registering as John Doe from the company Public 
>>Domain, Yellow Brick Road 1, Tinseltown or something???

>Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>via MAIL by mailing in your registration card, THEN the company send you
>the patch which includes the info you put on the registration card.

>--Kasey Chang

I'm glad to see this idea come up because I've had something similar in mind.
What if you had an authorization key that computed from the name and address 
data.  When the user registers, you don't even need to send executable code, 
just compute his/her key and send him/her instructions to enter in the 
appropriate place the following:

Name=Joe Doe
Address=123 Main Street
City=Anytown, CA
key=ldslfoialsdkcdsngsikhsfd

Every user needs a unique key.  The executable can propagate as much as you 
like, the author can respond to the registration by e-mail, post card, 
whatever.  Unauthorized users would have to put up with someone else's name 
showing up (maybe on a main menu screen as well as a startup message).  
Authorized users can make as many copies as they like, upgrade their 
machines, whatever.  The main motivation here is guilt and irritation at 
seeing someone other than yourself as the "registered owner".

Newsgroup: sci.electronics
Document_id: 54104
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead Acid batteries & Concrete?

In article <9649@tekig7.PEN.TEK.COM>, alany@tekig5.pen.tek.com (Alan Yelvington) writes:
|> The battery goes dead primarily becaust the floor is cold.  The temperature
|> combined with self-discharge promotes sulfation which ruins the plates of 
|> the battery.  I strongly suspect that the only reason the battery doesn't
|> go dead as quickly on a dirt surface is because cement tends to be quite
|> cooler.

Please explain how cement is able to maintain a lower average temperature
than dirt.  Sheesh.......



Newsgroup: sci.electronics
Document_id: 54105
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Pin-out for 27C64??

In article <skelly.18aw@amiganet.chi.il.us>, skelly@amiganet.chi.il.us (Sean Kelly) writes:
|>  
|>  
|>      Does anyone know the pin-outs for the 27C512 EPROM??  I have bought
|> several of them, none of which has come with the pin-outs!  Any info would be
|> appreciated....

A good source of information for data of this type is the library.
In particular the library at a local college or technical school offering
courses in electronics would have data books of this nature.


Newsgroup: sci.electronics
Document_id: 54106
From: little@nuts2u.enet.dec.com (My name is...)
Subject: FOR SALE: OMTI 3527 : ST-506 RLL to SCSI adapters


I have 2 OMTI 3527 SCSI adapters for sale.  These make an ST-506 RLL drive
look like a SCSI disk drive.  Each adapter will support two RLL drives.  I
have used this model OMTI adapter with my Amiga A500 and a C-Ltd SCSI host
adapter without problems. I'm selling these because I got them about the
same time I decided to sell instead of expand my Amiga so I have never even
used them.  I can't guarantee they will work with every SCSI host adapter.

They are essentially new in box. I paid $150/ea, make me an offer.

Regards,
Todd
(708) 202-1030
little@pecan.enet.dec.com

Newsgroup: sci.electronics
Document_id: 54107
From: witr@rwwa.COM (Robert Withrow)
Subject: Re: Cable TVI interference

In article <1qf44aINNll@rave.larc.nasa.gov>, watson@nimbus.larc.nasa.gov (Catherine Watson) writes:

| I gave up after a year of
| letters and phone calls.  I got the impression the FCC was powerless and it 
| was up to the cable company to correct the situation.

Isn't there some *formal* action a citizen can take that *requires* the
FCC to, at least, generate some paperwork?

-- 
 Robert Withrow, Tel: +1 617 598 4480, Fax: +1 617 598 4430, Net: witr@rwwa.COM
 R.W. Withrow Associates, 21 Railroad Ave, Swampscott MA 01907-1821 USA

Newsgroup: sci.electronics
Document_id: 54108
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr23.190152.13088@mprgate.mpr.ca> vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>In article <9649@tekig7.PEN.TEK.COM>, alany@tekig5.pen.tek.com (Alan Yelvington) writes:
>|> The battery goes dead primarily becaust the floor is cold.  The temperature
>|> combined with self-discharge promotes sulfation which ruins the plates of 
>|> the battery.  I strongly suspect that the only reason the battery doesn't
>|> go dead as quickly on a dirt surface is because cement tends to be quite
>|> cooler.
>
>Please explain how cement is able to maintain a lower average temperature
>than dirt.  Sheesh.......

It's not the temperature, it's the karma.  You see, dirt has good karma,
since it's all organic and full of living things, but cement is all squared
off and artificial looking, and has lost its karma in the process.  Being
a karma sink, it sucks all of the good karma out of the battery which is no
longer able to keep a charge.  Because wood is also good and organic, putting
a board between the battery and the cement will fix the problems.

The Buddha-nature is in the acid, but it is also in the lead plate.  The
novice asked the master whether the spongy lead had more of the karma or
whether the solid lead had it.  The master handed the novice a 250V B battery,
terminals downward, and thus the novice was enlightened.
--scott

Newsgroup: sci.electronics
Document_id: 54109
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Question on addressing...

In article <skelly.18c2@amiganet.chi.il.us>, skelly@amiganet.chi.il.us (Sean Kelly) writes:
|>  
|>  
|>      I have a question about accessing certain addresses on a chip,
|> particulary a 27C512 EPROM.  Although I don't know that much about it, as I
|> understand it, there's a pin on the chip that, when voltage is applied, kicks
|> up the address.  The question is how do you determine how many bytes the
|> address is incremented by??  For example, if I have code I want to be
|> accessed at $2000 and also at say $4000 how do I move the address pointer to
|> those positions??  Thanks for any info...
|> 
|> %^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%
|> %   Sean Kelly - Sysop Amizon BBS (312)594-1146                         %
|> %   Always looking for classic video games for the following systems:   %
|> %                                                                       %
|> %  Atari 2600-Atari 5200-ColecoVision-Atari 5200-Intellivision-Vectrex  %
|> %^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%^%

Judging by your .sig you are trying to make some kind of game cartridge.
Information of how to build an EEPROM cartidge for the vectrex is available
via anonymous ftp at 'csus.edu'.

Since you've chosen the 27C512 you are probably trying to make a 'multicart'.
To do this simply:
1. Load the game images into the EEPROM at $2000, $4000, etc. (Your EEPROM
burner software may allow this or you will have to assemble the images into
one file yourself with suitable gaps.)
2. Wire up the cartridge with the lower address bits going to the game
console, and the high bits going to switches to choose between games.

To directly answer your question above, the pin that 'kicks up the address'
is simply another address line.

For a concrete example, with the 27C512 and 8K games images, you would
wire A0-A12 to the cartridge, and A13-A15 to 3 switches.  The 3 switches
would allow you to pick from the 8 games on the EEPROM.


Newsgroup: sci.electronics
Document_id: 54110
From: stevenm@kralizec.zeta.org.au (Steven Murray)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


>>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>>	Hello again,
>>> I asked this a year ago, but i am still looking.
>>> I am getting sick of having to use a HC373 

If you are just getting sick of the real estate used by the HCT373, you could
always use the approach I have seen one designer take - he stuck the chip in
the middle of the EPROM socket, under the EPROM.  Naturally, you have to use
an IC socket with the right dimensions, but layout is really easy.

-Steven Murray

Newsgroup: sci.electronics
Document_id: 54111
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Question on addressing... (correction)

A little correction on my previous post about an hour ago.
Please replace the term 'EEPROM' with the term 'EPROM' wherever it appears.
(Don't not why I added that extra 'E' every time.)


Newsgroup: sci.electronics
Document_id: 54112
From: Carr-C10973@email.comm.mot.com (Eric Carr)
Subject: Re: help with phone wire: which ones are "tip" & "ring"?

In article <1993Apr22.103922.23177@husc3.harvard.edu>,
mlevin@husc8.harvard.edu (Michael Levin) wrote:
> 
> 
> I just bought a little gizmo that is supposed to be installed "in
> series with the tip or ring lines" of the phone wire. Which ones are
> those? Suppose I am holding a regular phone wire, such that the little
> plastic tooth (on the little plastic square thing with the naked lead
> ends that you plug into the phone) is facing down, and away from me.
> Which of the 4 wires that I see is the "tip" and which is the "ring"?
> Please reply to mlevin@husc8.harvard.edu.
> 
> Mike Levin

Assuming you are refering to standard POTS or ground start lines:

If you are looking at loop start lines under idle conditions, the RING
conductor is the one with approximately -48 to -52 vDC with respect to
ground while the TIP conductor is at or very near ground potential (be sure
to reference the telco ground when taking your measurements).  

If you are dealing with ground start lines under idle conditions, the RING
conductor will be the one with approximately -48 to -52 vDC while the TIP
conductor would look like it's floating (you may see some potential from
line capacitance it will bleed off over time).  Remember to use the telco
ground as your reference when making measurements. 



                                   _________
                            ______/        /_______
                           /     '67 Caprice      /
                          /_____ Sport Coupe_____/
                                /_________/


                              
                                          

Newsgroup: sci.electronics
Document_id: 54113
From: seema@madvlsi.columbia.edu (Seema Varma)
Subject: Luser!

Hi,
	I am looking for a very high speed 
D/A converter (at least 8bits and 150MHz) for
a research application. A paper in  the January
issue of IEEE Solid-State Circuits mentions a 
GaAs, 1GHz, 8bit DAC - anyone know where I can find
such a thing? Even a somewhat slower Si DAC would
do.
	Needless to say, I have looked in all the
conventional places (Vitesse, Motorola, National,
etc. etc.). Any pointers would be appreciated.

--- Seema Varma

Newsgroup: sci.electronics
Document_id: 54114
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu>
sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes: 

backupable, if restored to the same machine >>(depends>> on the
programmer...  don't use a disk drive characteristic!) If the user >> did
an upgrade to the machine, he/she should reinstall all programs any way.
>> No document look-up, no disk wear-and-tear! > 

> This is not a good idea.. I upgraded my motherboard last fall.  I >would
have been quite pissed at any software that would have forced me to
>reinstall simply because I changed motherboards. >

Opinion is understandable.  :-)  I assume you have a tape drive?  Not all
of us have about 200 floppies around for backup, you know.  

> Any info in the BIOS is too volatile to use as a checksum.  Are you
>going to require that a user re-install all their software if they add
4Mb >of RAM to their computer?  I did that a couple of weeks ago.  It's in
the >BIOS, and if software had told me "this isn't the machine you
installed me >on" I would never have used that software again.  Really bad
idea. 

RAM is something you add all the time, so no.  It's more like BIOS
manufacturer and/or processor type (386/486/etc).  Data cannot be used,
esp with these new Flash ROM BIOS machines with updates on a diskette.

On the other hand, to make this LESS intrusive it could be disguised as
"Please Insert Original Disk #XX as I need file YYYYYY for update".  :-) 
It would be perfectly reasonable...  Sort of.

> >> I did not say that the originals would allow only one install.  The
user's >> conscience should do that. 

> > This is silly.  It's much easier to loan disks to a friend and let
>them do an install than to backup your copy already on disk, and then
give >them that.  Your scheme isn't going to stop anyone. 

Of course it is easier.  Are you saying then the originals SHOULD allow
only one install?  What is your point?

> >> You know how many bytes you need to change in X-wing to disable >>
the quiz?  TWO!  Yes, TWO!  (And don't ask me which ones they are.)

> > Do you know any assembly language at all?  All anyone needs to do if
>find the part of the code that does the quiz, and insert a JMP
instruction >to just completely skip it.  Not that difficult, really!  And
there is very >little that commpanies can do to stop this type of thing. 
Using PKLITE or >some similar utility would help, but only if the
resulting compressed .EXE >were tagged as uncompressable. 

I know x86 and 680x0 assembly quite well, thank you.  I know exactly which
two bytes need to be changed, I have the code to do them too.  I just said
"Don't ask me which ones."  I didn't say I don't know what that means.

Such hacking can be EASILY discouraged by adding anti-patching code which
does a self-check upon execution and refuse to load if CRC does not match
value stored (encrypted, of course) in the program.  It could be claimed
as a part of anti-virus code, and it would not be far from the truth. 

> >> What I believe the companies should do is implement the above plus >>
a special patch once the user registers that loudly exclaims upon bootup
>> "REGISTERED TO XXXXX -- address, city, state zip" and disables the
above. 

> > This is by far the best idea you presented in your post.  Making it
>plainly obvious who registered is going to stop casual pirates. But, the
>determined ones are just going to answer "Joe Blow" to the question of
>"what's your name" so this won't stop them in the long run. 

Did ANYONE read what I wrote?  That is NOT what I wrote! (or meant!)  

What I said was the program should have certain restriction (such as the
restrict-to-one-machine) UNTIL the program is registered with the
manufacturer.  The manufacturer will then supply the
then-proven-legitimate-user with a patch that will disable the restriction
and PROUDLY PROCLAIM the legal copy with the "Registered to XXX" screen.

> > Pirates are always going to win this fight.  They simply have more
>time to work on the software and figure out the protection scheme. 

Of course they will, but that was NOT my point.  The purpose of copy
protection is to discourage casual pirates ("Oh, can I have a copy of
that?"/"Sure, here.") and the less sophisticated pirates ("Let's look for
all those calls to INT13H...") .  Any one determined enough to break copy
protection can and will succeed.  They can always backtrace the entire
load-sequence of the program.  The point of copy protection is to make
such attempts take as long as possible while not intruding upon the uses
(or to minimize such intrusion) of legitimate use.  Pirates who see copy
protection as a challenge love breaking them, and no amount of copy
protection will stop them, but the rest of us WILL be stopped.  How many
of these hardcore pirates are there compared to rest of us?  Not that many.

--Kasey Chang

Newsgroup: sci.electronics
Document_id: 54115
From: ebraeden@magnus.acs.ohio-state.edu (Eric W Braeden)
Subject: What exactly is an IBM 486SLC processor?

Could someone please tell me if the 486SLC and 486SLC2 processors
IBM is putting in their Thinkpad 700's and other PC's is a REAL
486 with a math coprocessor or if it is really some Kludge that
should not be called a 486 at all?

Thanks,
Eric
-- 
Eric W. Braeden                    | "Der Verstand war zwar praechtig
Ohio State University              | doch das Nuetzte am Ende nicht viel"
ebraeden@magnus.acs.ohio-state.edu | Peter Schilling   120 Grad    1983

Newsgroup: sci.electronics
Document_id: 54116
From: neal@cmptrc.lonestar.org (Neal Howard)
Subject: Re: Lead Acid batteries & Concrete?

In article <C5x3E6.3nx@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>>
>>  Why does a lead acid battery discharge and become dead (totally unuseable)
>>when stored on a concrete floor?  
>>  I decided to bring the battery in from the lawn mower and the motorcycle
>>from the unheated garage this year, *to preserve them* and I just
>>went to use them and noticed that not only do they not work, but 
>>they act like the two terminals are shorted.  I asked a friend
>>and he said that you should never do that, 'cause it ruins them,
>>but he couldn't tell me why.
>
>This topic was beaten to death a year or so ago.
>
>The concrete is not the problem. 
>
>Lead-acid batteries often fail from disuse (not being charged for a long
>time), but there's no way the concrete floor could be the cause of the
>problem.

The concrete floor accelerates the problem because it is a heat sink and a
colder lead-acid battery self-discharges at a slightly faster rate. That's
why the old wives' tale of sitting it on a piece of wood on the floor works
to help keep from killing the battery as fast ---- it insulates the battery
thermally. It you'll set the battery down on a piece of styrofoam, it will
self-discharge even slower. The best thing would be to attach a small load
such as a small transistor radio with the volume turned down low and leave it
on constantly, but also trickle-charge it every couple days too to "shallow-
cycle" the charge in the battery. Such mild "exercising" of a lead-acid
battery is the next best thing to completely removing the electrolyte for
storage. If you do remove the electrolyte, may sure you keep separate storage
containers for each cell's electrolyte and put it back into the same cells
when you refill the battery. This isn't so critical for a brand-new battery
in a fully charged state, but will maximize the restored output of an older
battery which may not be fully charged when you remove the electrolyte for   
storage.
-- 
=============================================================================
Neal Howard   '91 XLH-1200      DoD #686      CompuTrac, Inc (Richardson, TX)
	      doh #0000001200   |355o33|      neal@cmptrc.lonestar.org
	      Std disclaimer: My opinions are mine, not CompuTrac's.
         "Let us learn to dream, gentlemen, and then perhaps
          we shall learn the truth." -- August Kekule' (1890)
=============================================================================

Newsgroup: sci.electronics
Document_id: 54117
From: wiegand@rtsg.mot.com (Robert Wiegand)
Subject: Re: Lead Acid batteries & Concrete?

camter28@astro.ocis.temple.edu (Carter Ames) writes:


>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)

>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.

I don't see any way that the concrete floor could do anything to the
battery.

However, you would have been better off leaving them outside. Keeping
them cold would have been better for them than bringing them inside.
A warm battery will self-discharge faster than a cold one.

When you are storing a battery it's a good idea to charge it once a month.
Letting a battery go completely dead is bad for it (I suspect this is
what caused your problems).

-- 
------------------------------------------------------------------------------
Robert Wiegand - Motorola Inc.
wiegand@rtsg.mot.com
Disclamer: I didn't do it - I was somewhere else at the time.

Newsgroup: sci.electronics
Document_id: 54118
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: NEED help finding parts!

OK I posted this B4 but:

___ Blue Wave/QWK v2.12
                                                                              

Newsgroup: sci.electronics
Document_id: 54119
From: klp@doe.carleton.ca (Ka Lun Pang)
Subject: Self-destructing copy protection on VHS tape?


Hi folks,

I borrowed a VHS tape from a friend and it has a warning in the begining saying
that attempts to copy the tape will result in destroying the copy and the
original. I found this unbelievable as playing and recording are two different
processes. However, I've never seen this tape being sold anywhere so I don't 
want to take the chance even it's small.

Anyone has experience in this kind of self-destructing video tapes?

Thanks in advance.

--
Ka Lun  Pang (a.k.a. Andy) - Lost between frequency and time on the unit circle
                      email: klp@doe.carleton.ca 
                               DoD# 0687

Newsgroup: sci.electronics
Document_id: 54120
From: Mark Yeck <my10+@andrew.cmu.edu>
Subject: D,G,&H type Amplifiers

Hey, can someone clue me in on these and other weird types of amplifiers?  Just
a brief intro to the concepts behind these would be cool.  I have the clues 
on type A, B, and AB already and stuff, but these other ones are mentioned 
occasionally and I dont know what they do.  I think type D is like a PWM scheme
or something.  Thanx in advanced.


-mark
(my10@andrew.cmu.edu)

Newsgroup: sci.electronics
Document_id: 54121
From: tl@etek.chalmers.se (Torbj|rn Lindgren)
Subject: Re: How to the disks copy protected.

In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu> sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes:
>	Do you know any assembly language at all?  All anyone needs to do if
>find the part of the code that does the quiz, and insert a JMP instruction
>to just completely skip it.  Not that difficult, really!  And there is very
>little that commpanies can do to stop this type of thing.  Using PKLITE or
>some similar utility would help, but only if the resulting compressed .EXE
>were tagged as uncompressable.

And even that doesn't help, there are at least two programs available
that fixes this (UNP and DISLITE, both available from Simtel-20). And
even without them it isn't THAT hard to fix.

Newsgroup: sci.electronics
Document_id: 54122
From: jott@scarecrow.cse.nd.edu (John Ott)
Subject: RE: Food Deydrators


Article: 41686 of sci.electronics
Newsgroups: sci.electronics
Path: news.nd.edu!spool.mu.edu!howland.reston.ans.net!bogus.sura.net!news-feed-1.peachnet.edu!gatech!asuvax!ennews!mcdphx!schuch
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Food Dehydrators
Message-ID: <1993Apr19.154356.17880@phx.mcd.mot.com>
Sender: news@phx.mcd.mot.com
Nntp-Posting-Host: bopper2.phx.mcd.mot.com
Organization: Motorola Computer Group, Tempe, Az.
Distribution: usa
Date: Mon, 19 Apr 93 10:43:56 EST
Lines: 9

>  Does anybody out there have one of those food dehydrators I've been seeing
>all over late-night TV recently? I was wondering if they use forced air, heat,
>or both. If there's heat involved, anybody know what temperature they run at?
>My wife would like one and I'm not inclined to pay >$100.00 for a box, a fan
>and a heater. Seems to me you should be able to throw a dehydrator together
>for just a few bucks. Heck, the technology is only what? 1,000 years old?
>
>John

Try Mother Earth News, Feb/March 1993, pg 54, "Build a Food Dryer"

John

Newsgroup: sci.electronics
Document_id: 54123
From: jmiller@terra.colostate.edu (Jeff Miller)
Subject: Re: How to the disks copy protected.

: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
: via MAIL by mailing in your registration card, THEN the company send you
: the patch which includes the info you put on the registration card.

The problem with this scheme, is that when I buy a game, I want to play it
*THAT* day...mailing a card to and from California would probably take a week
or more.
--
 _____________________________________________________________________________
|                                                                             |
|  jmiller@terra.colostate.edu  |   Jeff Miller  |  TERRA Lab Systems Admin.  |
|_____________________________________________________________________________|

Newsgroup: sci.electronics
Document_id: 54125
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead Acid batteries & Concrete?

neal@cmptrc.lonestar.org (Neal Howard) writes:

>The concrete floor accelerates the problem because it is a heat sink and a
>colder lead-acid battery self-discharges at a slightly faster rate. That's
>why the old wives' tale of sitting it on a piece of wood on the floor works
>to help keep from killing the battery as fast ---- it insulates the battery
>thermally. It you'll set the battery down on a piece of styrofoam, it will
>self-discharge even slower.

There are a number of inaccuracies here:
1) In fact, a colder battery will self-discharge more slowly.  This is why
   batteries should be stored in a COOL, dry place.
2) An battery placed on concrete does not become colder than one placed
   on wood.  The battery, the wood, and the concrete will all be at the
   same general temperature (ignoring temperature fluctuations) and thus
   none will effect the other.

>The best thing would be to attach a small load
>such as a small transistor radio with the volume turned down low and leave it
>on constantly, but also trickle-charge it every couple days too to "shallow-
>cycle" the charge in the battery. Such mild "exercising" of a lead-acid
>battery is the next best thing to completely removing the electrolyte for
>storage.

There is no need to 'exercise' the battery.  Just keep it charged.  (A trickle
charger will do the job.)

[stuff deleted]

Newsgroup: sci.electronics
Document_id: 54126
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: !!!] HELP!  NEED 3479P!!! [!!!


                Would anyone have a few extra 3479P's lying around that I 
could buy off of them.. Problem is that around here I can only perchase 
them in $30 quantities, and I don't need this, and can't take this 
financially right now.... 
 
                        If anyone can accomodate me with this PLEASE 
reply to BOTH for the following mailing addresses...
 
                        Thanks!!!
 
_______________________________________________    
             |                                 |
   _______   |    Baden de Bari                |
  /       \  |     baden@sys6626.bison.mb.ca   |
 (| o   o |) |     baden@inqmind.bison.mb.ca   |
  |   ^   |  | >> True life can only           |
  \  -=-  /  | >> be experianced by            |
   \_____/   | >> those who do not fear death. |
-----------------------------------------------


Newsgroup: sci.electronics
Document_id: 54127
From: weaver@kuttner.sfc.sony.com (Eric Weaver)
Subject: Re: ATARI 2600 Processors


I'm a 2600 hacker from The Old Days.  Let's see how much trouble I can
get into by telling you what you want to know...   ;-}
-- 
Eric Weaver  Sony AVTC  677 River Oaks Pkwy, MS 35  SJ CA 95134  408 944-4904
& Chief Engineer, KFJC 89.7 Foothill College, Los Altos Hills CA 94022

Newsgroup: sci.electronics
Document_id: 54128
From: erini@enterprise.ifp.uiuc.edu (Erini Doss)
Subject: CELLULAR ANTENNAS

 i need to get some info a.s.a.p. about the cellular
antenna market out there right now:  who are the main
companies making them, how much do they cost, what are
the specs (such as gain , directivity, etc.), and who
is the contact person because a group of us here are
at the Univ.of IL are researching into this technology


I will personally mail you a copy of our entire busineess
plan and paper if you can be of any help..

e-mail me at erini@enterprise.ifp.uiuc.edu



Newsgroup: sci.electronics
Document_id: 54129
From: erini@enterprise.ifp.uiuc.edu (Erini Doss)
Subject: CELLULAR ANTENNAS

 i need to know about the market for cellular antenna
technology today... who are the main companies in the
market.. how much are they selling them for? who are the
contact people?  what are the specs?

I will mail oyou our reserach so far if youcan help us!!


erini@ifp.uiuc.edu



Newsgroup: sci.electronics
Document_id: 54130
From: triumvir@cco.caltech.edu (Martin W. Lin)
Subject: Audio/Electronic Parts, esp in Los Angeles

I'm working on an audio mixer project, but I'm having trouble finding
parts.  I want to use op-amps for the gain control stages.  The ones
I have found that are good for audio are LM739 and LM833, but I cannot
find either of these in the electronic parts places I've looked.

Are there any good substitute op-amps and/or are there any parts
suppliers in the LA area that carry this kind of thing (10KOhm dual
audio taper slider pots would be nice, too).

Any info would be appreciated.  Thanks in advance.

Martin Lin
triumvir@cco.caltech.edu


Newsgroup: sci.electronics
Document_id: 54131
From: maynard@selway.umt.edu (Robert L Maynard)
Subject: Re: How to the disks copy protected.

> noeler@xanth.CS.ORST.EDU (Eric Richard Noel) writes:
> >
[Discussion on Piracy Deleted]
> 
> Off deeper end-> Why does everyone think they need to be able to make a 
> backup copy? Almost all new software must be installed to the hard disk,
> so you are left with the originals as your backups. I think its a waste
> of time, space, and money, as well as it makes it to tempting to "lend"
> out the backups. 
> 
My own practice with new software :

make a copy of the original floppies to a second set of floppies.

install to hard drive from second set of floppies.

put originals in a box in room number one.

put copies in box in room number two.

1) Accidents DO happen to original floppies.
2) Accidents CAN happen to the installation floppy.
3) Sometimes software goes out on floppies that are JUST marginally good.  Or
   gets too close to a magnet in shipping or storage.

I've had experience with SOMETHING like the last.  I purchased a compiler from
a reputable vendor.  THe debugger in the package just would NOT install to the
hard drive. NO WAY.  Repeated floppy-to-floppy copies FINALLY got a clean read
of the disk.  I DON'T recall if I used "diskcopy", "copy/b", or "xcopy".

I made a second copy of the marginal floppy and installed from that.  No problenms ( except with my typing :-)  ) since.

I regard backup floppies as CHEAP insurance.

Just my side of the question...

Bob

Newsgroup: sci.electronics
Document_id: 54132
From: jeh@cmkrnl.com
Subject: Re: Los Angeles Freeway traffic reports

In article <C5sLMB.9w6@cup.hp.com>, dclaar@cup.hp.com (Doug Claar) writes:
> While driving through the middle of nowhere, I picked up KNBR, AM 1070,
> a clear-channel station based in Los Angeles. 

KNX AM, 1070 in LA, will be unhappy to hear about this, I'm sure. :-) 

(isn't KNBR in the bay area?)

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
Document_id: 54133
From: gladman@ecf.toronto.edu (GLADMAN AVIV)
Subject: Re: Blue LED's

In article <Zw6F3B1w165w@inqmind.bison.mb.ca> baden@inqmind.bison.mb.ca (Baden de Bari) writes:
> 
>        So what's the story here... we're all stuck with the regular
>green, red, and off yellow-orange LED's!?  What gives!!??
>        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
>

In order to emit blue light, a semiconductor must have a band gap energy
within the region of 2.6 to 2.8 electron Volts. According to my physical
electronics prof, you can't get an LED with that band gap. That's why you
don't find blue LEDs or, for that matter, some other colour of LEDs. That
is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
but they were just your typical visible light LED in a blue plastic covering.
They didn't emit very much light...

Source: Solid State Electronic Devices (Ben G. Streetman, 3d ed., Prentice
Hall)
-- 
-----------------------------------------------------------------------------
"Right planet, wrong universe" - Douglas Adams
"If we took the bones out, it wouldn't be crunchy" - Mr. Whizzo
-----------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54134
From: stone-andy@cs.yale.edu (Andy Stone)
Subject: Re: How to the disks copy protected.


	I wrote a commercial program called GAME-MAKER (can you guess what
it does).  What we do is have a document protect (answer Question on page x, 
line y), which is a real pain.  We also allow the user to register by sending
in a card, and computing a # based on their name.  The system works in that
we've gotten lots of registration cards.
	I hear that the program has been cracked though.  Someone two people 
actually called up my support--one with a question, the other wanting to
buy our graphics libraries (right!).  Anyway if anyone wants to help me
catch a cracker and has the cracked version, mail me.  I won't accuse
you (unless you're the cracker of course).

--
                                             Andy Stone      
-					     stonea@suned.cs.yale.edu
-- 
                                             Andy Stone      
-					     stonea@suned.cs.yale.edu

Newsgroup: sci.electronics
Document_id: 54135
From: davidj@rahul.net (David Josephson)
Subject: Re: Blue LED's

In <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:

>In article <Zw6F3B1w165w@inqmind.bison.mb.ca> baden@inqmind.bison.mb.ca (Baden de Bari) writes:
>> 
>>        So what's the story here... we're all stuck with the regular
>>green, red, and off yellow-orange LED's!?  What gives!!??
>>        Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
>>

>In order to emit blue light, a semiconductor must have a band gap energy
>within the region of 2.6 to 2.8 electron Volts. According to my physical
>electronics prof, you can't get an LED with that band gap. That's why you

He's mistaken. They exist, the semiconductor is silicon carbide, and they
are inefficient and expensive. The bandgap is around 2.7 ev.

>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...

The ones I have are clear plastic. Pray tell, what would make a "typical"
LED emit blue light?


-- 
David Josephson <davidj@rahul.net>

Newsgroup: sci.electronics
Document_id: 54136
From: ptorre@hardy.u.washington.edu (Phil Torre)
Subject: How to drive an array of LEDs?

I have a project in mind that requires an array of LEDs that can be addressed
individually by a microprocessor (say, 16x16 or so).  Is there an LSI that
is designed to drive an LED array (including RAM to hold the array state),
or failing that, some way of multiplexing the display so I don't have to
latch a bit for each LED using a discrete latch?  (I want to avoid having
a huge board covered with 373s if possible!)  Thanks in advance...

Phil Torre (ptorre@u.washington.edu)

Newsgroup: sci.electronics
Document_id: 54137
From: rpo@trsvax.tandy.com
Subject: Re: IR detector 'cards'???


Radio Shack stores sell them here in the States. Not sure if
InterTan is carrying these for Australia or not...

Cost is $6 USD. You charge them under a fluorescent, then
they glow when exposed to IR.

Paul Opitz
Radio Shack Publications


Newsgroup: sci.electronics
Document_id: 54138
From: alung@megatest.com (Aaron Lung)
Subject: Looking for Toshiba TA6267 specs

I'm looking for some specs for a Toshiba TA6267-BP.  It appears
to be a power amp housed in a 7-pin inline package and is used
in my Mitsubishi VCR, circa 1985, as a DC motor controller for
the tape drive.

Checking in the oldest IC Master I have (1990), I don't see it
listed, and it appears to have been discontinued.  If anyone
has anything on this part, I'd be *greatly* indebted!

thanks in advance,

aaron

Newsgroup: sci.electronics
Document_id: 54139
Subject: Re: Power, signal surges in home...
From: emd@ham.almanac.bc.ca

clewis@ferret.ocunix.on.ca (Chris Lewis) writes:

> In article <1r1jmoINN8mb@rave.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Sc
> >In article <DRAND.93Apr20150701@spinner.osf.org> drand@spinner.osf.org (Doug
> >>In article <randall.735251839@woof> randall@informix.com (Randall Rhea) wri
> 
> >>   Hams can legally run up to 1500 watts.  It is very unlikely, however,
> >>   that a ham would be running that kind of power from a car.  Ham rigs
> 
> >>Not possible either.  You'd need about a 300 amp alternator for
> >>just the amplifier.  I can just see it.  You need to slow
> >>down on a downgrade,  so you hit the push to talk button.
> 
> >Now, that indeed is possible.  A good friend of mine is running about 1 KW
> >PeP from his car.  Yes, he does have a second alternator.  Yes, he calls
> >the rig an "electronic brake" since the engine noticeably slows when the
> >key is down.
> 
> It has been a while since I knew the electronics of ham radio, but I seem
> to remember that PeP is actually 4x the "real" power.  Which makes 1KW PeP
> actually around 250W.  Or was it 2x?  I disremember.
> 
> "Effective transmitted power" is also "odd", in that it takes into account
> antenna height and geometry.  Which is why a TV station with a 50KW Klystron
> might advertise a megawatt (if their antenna is on the top of the
> CN tower ;-).
> 
> This is like Sears HP ;-)
> 
> Though, 1500 real watts still isn't impossible.  About 125-150A with
> a 12V alternator, less if the alternator produces higher voltages.
> 
> It's only three horsepower (taking into account inefficiencies).  You'll
> feel it when you hit the key.  But not too much.
> -- 
> Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
> Psroff 3.0 info: psroff-request@ferret.ocunix.on.ca
> Ferret list: ferret-request@ferret.ocunix.on.ca


It sorta depends on what you drive. I remember running a two channel 
Motorola with a vibrator power supply and about 40 tubes in a 1958 
Volkwagen. The poor little 6 V generator had a heck of a time, and if you 
keyed the mic at night, you needed to be stationary, because your lights 
got AWFUL DIM. Isn't progress wonderful?


emd@ham.almanac.bc.ca (Robert Smits Ladysmith BC)

Newsgroup: sci.electronics
Document_id: 54140
From: adrian@tasman.cc.utas.edu.au (Adrian Lewis)
Subject: cleaning electronic equipment?

Hi,
	Just a quick question.  What standard lab solvents can be used to
clean electronic equipment and components safely (ie not corrode, dissolve,
short-out, etc the equipment)?
	water?	:-)
	methanol?
	CCl4?
	etc?
I am not an electronics type (surprise, surprise), and I want to avoid using
freons.

Thanks,		Adrian


Newsgroup: sci.electronics
Document_id: 54141
From: ejajko@hertz.elee.calpoly.edu (Edward Jajko)
Subject: Re: How to the disks copy protected.

In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU (Eric Richard Noel) writes:
>I strongly disagree. I think most pirating is done by amateurs, who won't
>copy the program if "diskcopy" can't do it.

I hate to disagree, but I will. :)
(note: I don't pirate software, nor do I trade it. I simply have met and
talked extensively with those who have. that's it. the FBI can tap someone
else's phone :)
Most pirating is done by people who don't use the programs they pirate.
A cracked program tends to get passed on, resplendant in the various graphics
and animations that advertise whoever performed the modification(s).

I admit that a large portion of the business world is involved in 'giving'
copies of programs to one's fellow workers, maybe taking it home for use
on one's own PC, but such trading tends to be interdepartmental or at most
spread throughout the business as a whole- how many times have you had
someone walking from business to business letting people copy disks?

It's mostly a matter of convenience: a person sees a program they want to
use and they feel justified in making a copy since "someone's already paid
for it", etc., etc. (A note: this is starting to change a bit. not much
though.)

>If you're talking a 20% max goal of pirated copies, I bet that anything that
>will beat diskcopy, and can't be easily copied from a hard drive, will
>suffice.

what about commercially available copy programs? CopyII?
how about programs like teledisk, that can do things diskcopy can't?
and before anyone disputes this because they feel that those who would copy
wouldn't know about this:
  after working with people around computers, one comes to realize that
the 'average' user doesn't know much. Any computer enthusiast is at least
200x better at pre-guessing commands and how to use them (can *you* sit down
and use something without reading the manual?) and it is these people who
are doing the '20% pirating', not Joe Windows User who can't remember a few
arguments to the dir command.

>I hate hard copy manuals, and would rather have all docs online - *not*
>because I want to copy the program, but because its usually faster and
>and convenient than sifting through an old book I can't find.

really? I find it evens out- the online stuff can be read through faster,
but you're stuck reading it in linear flow: start to finish, unless you
jump ahead with a search or such. A book, though, you can flip through
faster than you can read text on a screen and they usually have a nifty
index too!

But I partially agree: I often wish I could grep something that was written
down.

>Off deeper end-> Why does everyone think they need to be able to make a 
>backup copy? Almost all new software must be installed to the hard disk,
>so you are left with the originals as your backups. I think its a waste
>of time, space, and money, as well as it makes it to tempting to "lend"
>out the backups. 

what if they need to re-install? The idea of a backup still holds- if
the original disk goes bad, they're out of luck for about 1-2 weeks, which
is the usual turn around time for a company to send a new set of disks-
if they'll do it without a charge.

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
::::::::::::::::::::::::::::::: Edward W. Jajko :::::::::::::::::::::::::::::::
::::::::::::::: The Nekomancer :: ejajko@hertz.elee.calpoly.edu :::::::::::::::
::::::::::::::::"Mein Fuhrer! I can walk!!" -Doctor Strangelove::::::::::::::::
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Newsgroup: sci.electronics
Document_id: 54142
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <CSTROCKB.93Apr23002520@csws8.cs.sunysb.edu>, cstrockb@cs.sunysb.edu (Caleb Strockbine) writes...

>Could make for some interesting choreography... light and sound could be 
>controlled directly by the position of a dancer on stage, or by the number
>of dancers on stage. Neat.
> 
>You could even build a spotlight that follows the dancer around on stage!
> 
>Can you tell us more about what you're doing? Sounds like a very cool program.

Tis' only a gleam in my eye at this point.  I have yet to chose a tracking 
method.  The initial requirement was to design a system to locate a dancer
in one of eight zones across the stage.  I did some experiments with 
pyroelectric detectors and found them difficult to align to get a definite
zone transition.  And dancers stand still alot, so their IR signature goes
away.  The good thing about pryoelectrics is that their signal is proportional 
to the size of the warm body (or body part), and the velocity of said body.
This could be useful for detecting the intensity of a dance gesture.

Dancers also really hate to wear little boxes and batteries strapped on their 
bodies, but they really need to be emitting some kind of signal to be tracked.

The current toy I have been working with is a program called Mandala for the
Amiga, used with a LIVE! video digitizer.  This works with a video camera 
trained on the stage.  You can set thresholds for a zone within the field of
view, and an object brighter than the threshold will trigger an event. Events
can be MIDI objects or sequences, Amiga sounds or graphic objects.  It's been
fun to play with, but the documentaion is arcane, and the digitizer is noisy.
Still, it's very appealing, the dancers don't have to wear any appliances,
you can have ots of zone,s, it speaks MIDI, which can be used to control lights,
and I don't have to build any electronics.  It's all done with lighting and
video brightness and contrast adjustments.  I have yet to do anything
particularly useful or artistic, but I have hopes...


Newsgroup: sci.electronics
Document_id: 54143
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Need help with video detection circuit

verity@jack.sns.com (Steve Verity) writes:
> I am trying to build a circuit that detects the presence of video (Vs.
> a blank screen) by monitoring the R,G, and B outputs of a graphics
> card.  It should be able to detect the presence of a single pixel at
> 65 MHz, which would mean detecting a 15 NS pulse.  It should also be
> able to tell the difference between a blank screen (about 300 mv)
> and a dim screen (say, around 310 mv).  Oh yes, it also needs to be
> cheap.  ............... In 
> fact the difference between completely black and completely white is
> only 650 mv.  I am wondering if I am going to have to amplify the
> video signals to make this work.  

Try a differential amplifier. Put back-to-back diodes between the collectors
restrict the voltage swing. Have 10 mA flow, with 500 ohm collector Rs, and
keep the stray C below 10 pF. Try 2N5179s. Run collector to your logic.
Allen Sullivan     




Newsgroup: sci.electronics
Document_id: 54144
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>
>In order to emit blue light, a semiconductor must have a band gap energy
>within the region of 2.6 to 2.8 electron Volts. According to my physical
>electronics prof, you can't get an LED with that band gap. That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...

Um...

1) Your Professor if just plain wrong.  Although blue LEDs are one heck of
a lot less efficient than red ones.
2) "Typical visible light LEDs" don't really exist.  LEDs have a fairly
narrow region of transmittence.  (Since the Fermi energy around either side
of the band gap falls off exponentially, blah, blah...)

>Source: Solid State Electronic Devices (Ben G. Streetman, 3d ed., Prentice
>Hall)

You might want to check the copyright date on that. :-)

Blue LEDs most certainly do exist, I've got a bunch at work.  Cree Research
makes them (probably along with other companies...  Cree is big in
materials science, though; they advertise in the stuff like Physics Today,
etc.).  You can buy them from JameCo (I think), DigiKey (definitely), and
plenty of other distributors.

Actually, these days you _can_ get a "typical visible light" LED -- it's
called a "rainbow LED", and I've forgotten who makes it (they advertise in
EDN and many of the other trade rags, though).  It combines a reg, green,
and blue LED all on one chip (and has four leads).  Nifty device, although
it's probably fairly expensive.

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 54145
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Long distance IR detection

sburton@dres.dnd.ca (Stan Burton) writes:..........
> I would like to be able to detect the angular position (low accuracy) of an
> IR emitting source at a distance of about 100 meters (more is better) in
> daylight.  The IR source could be emitting a signature; I'm leaning toward
> 30 KHz square wave with 50% duty cycle.
> 
I designed and built hardware in 1988 that would output a logic level (from
a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
variations in sunlight (and 60Hz from lights). Used no lenses.

Allen Sullivan




Newsgroup: sci.electronics
Document_id: 54146
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Power, signal surges in home...

> Though, 1500 real watts still isn't impossible.  About 125-150A with
> a 12V alternator, less if the alternator produces higher voltages.

Anyone claiming that 1500 "real watts" isn't possible in a mobile should
dig through their back issues of 73 (and, I think, QST) for a description
of the mobile installation of that most revered of OMs, W6AM.  As I recall,
this included a Heath 1kW (DC in) amp (what was that model number...SB-
something....  my mind is turning to the usual Friday mush...) and was run 
full-out CW fairly regulary.  The car's electrical system had been modified, 
including a rather seriously-heavy-duty alternator, but such an installation 
HAS been done, and so IS possible.  This installation was the source of
the legendary story of W6AM sitting in the car, and paging his wife over the
department store PA systems!


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
Document_id: 54147
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

> >Please explain how cement is able to maintain a lower average temperature
> >than dirt.  Sheesh.......
> 
I hope David isn't going to be too upset with me for sticking my nose
in here again, but here goes......:-)

It isn't the average temperature that is the key factor here, but rather
which is better at transferring the heat out of the (presumably warmer
than ground temperature) battery.  Call it a question of thermal
conductivity, or of insulating ability, or "thermal mass" - whatever you
like.  Question - why does a concrete floor feel cooler than the 
surrounding dirt when you place your hand on it?


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
Document_id: 54148
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Switching PS questions

> 	Anyways, I've built the basic up & down converters with pretty
> 	good results (>80% efficiency) but I'm running into problems
> 	when I try to design & build anything that puts out serious
> 	amps... I know it can be done (I have some 5V@200A guts on my
> 	bench) but something puzzles me: I'm using a simple choke as 
> 	the storage element (basicly a toroid with a single winding)
> 	but ALL commercial models use transformers with MANY windings.
> 	I traced a few and they seem to use some of the winding for
> 	the usual error/feedback but some of the others seem to loose
> 	me... What are they for? Better than that, anyone have a full
> 	schematic for one of these that I could get a copy of? I'd
> 	love to see how they manage to squeeze out so much from such
> 	low volume :-)

Most commercial switchers do NOT use magnetics for their energy storage;
that's handled by the big caps on the primary side, those which in a 
linearly-regulated power supply would be considered the "filter" caps,
coming right after the bridge.  The transformer is just that - a 
transformer.  It's there primarily to step the voltage up or down.  (Although
the inductance seen by the switch transistor on the primary side is NOT
negligible, as anyone who's zapped said transistor from either failing to
get one with a high enough breakdown voltage or neglecting to include a
"snubber" diode across it would tell you.  Actually, many transistors intended
for switcher use today have the diode built in.)

The basic switched-mode power supply operates something like this (in
a somewhat simplified manner):  The AC line is rectified to produce a
high voltage, more-or-less unregulated DC rail.  The energy storage (or
"filter") caps appear across this rail, as does the switching transistor.
The transistor chops the current into the primary side of the transformer,
resulting in stepped-up or stepped-down pulses out the secondary, which 
are then rectified and filtered.  At least one of the transformer's outputs
is sampled and fed back to the control circuit for the switching transistor,
which acts in a "pulse-width modulation" (PWM) fashion to control (by varying
the pulse width) the amount of energy being dumped into the primary, and
therefore the voltage coming out at the secondary.  The remaining outputs
may be allowed to simply run at whatever value they will, more-or-less
tracking the regulated output, or they may have some additional linear
regulation added.  You may also note that the feedback between the 
regulated output and the PWM control (which is most typically an IC)
is not done via a direct electrical connection; this is due to various
safety standards which require primary and secondary circuits to be
electrically isolated.  Often, the feedback path involves an optoisolator
to meet this requirement.

While the transformer isn't the primary energy-storage device in these
designs, this does not mean that the energy stored in the transformer can
be ignored; besides the inductive "kick" giving the switch transistor a
bad time (as noted above), you also need to worry about getting all the
energy that went *in* to the transformer back *out* again, one way or another.
In some designs, this happens more or less automatically - but in others,
you need to take special care to ensure that the transformer core doesn't
saturate, which again would have disastrous results (best left to the 
imagination! :-)).

I'm NOT by any stretch of the imagination a power-supply designer; 
hopefully, a real one will come along soon and clean up any gross errors
in the above.


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.

Newsgroup: sci.electronics
Document_id: 54149
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does any one know what is biggest ROM for present ?

        Please replay yxy4145@usl.edu
                             Thanks a lot


Newsgroup: sci.electronics
Document_id: 54150
From: jmacphai@cue.bc.ca (James MacPhail)
Subject:  Help! Need thermal specs for MC68030FE

I'm doing some work on the Mac IIsi and need some information on the CPU.
I have the Motorola MC68030UM/AD Rev. 1, but I fear it is out of date as it
does not have the characteristics for the CPU package type used in the IIsi.

What I need is the Theta (JC) Thermal Characteristic (the Junction to Case
thermal resistance) for the _PLASTIC_ FE style package.

If you have this info, I would appreciate your sending it by email as postings
suffer a few days delay here.

If you are keen on this stuff, I am also interested in a more accurate value
for the typical power dissipation. I'm assuming 2.25 Watts (using the 2.6 W
maximum at 0 C decreased the way the Pd drops in the 6801x as Ta increases).
If your manual has a chart of power dissipation, I'd like to know what it
reads at 25 C and 40 C.

Thanks for reading!

James MacPhail  jmacphai@cue.bc.ca  (on bounce try james@mirg2.phy.queensu.ca)

Newsgroup: sci.electronics
Document_id: 54151
From: ejm@coyote.datalog.com (E.J. McKernan)
Subject: Re: Lead Acid batteries & Concrete?

In article <1993Apr21.204556.21262@cronkite.ocis.temple.edu> camter28@astro.ocis.temple.edu (Carter Ames) writes:
>
>   I was just wondering one thing, actually two. ( I hope that this is the
>proper place to post this subject)
>
>  Why does a lead acid battery discharge and become dead (totally unuseable)
>when stored on a concrete floor?  
>  I decided to bring the battery in from the lawn mower and the motorcycle
>from the unheated garage this year, *to preserve them* and I just
>went to use them and noticed that not only do they not work, but 
>they act like the two terminals are shorted.  I asked a friend
>and he said that you should never do that, 'cause it ruins them,
>but he couldn't tell me why.
>

It's NOT the concrete floor that does it. The problem is that lead-acid
cells self discharge over time. Even high quality cells (Gates for instance)
will discharge 50-60% over a 3-5 month period of time. Non-sealed cells
self discharge even faster. If the battery was not completly charged
when left sitting, it probably discharged past the the point where cell
sulfiding occurs, which in many cases means a ruined battery.
-- 
   /|_|\   Datalog Consulting, Tucson, AZ
  ( . . )  ejm@datalog.com
   \   /   ...!noao!datalog.com!ejm
    \_/    

Newsgroup: sci.electronics
Document_id: 54152
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Laser vs Bubblejet?

Here is a different viewpoint.

> FYI:  The actual horizontal dot placement resoution of an HP
> deskjet is 1/600th inch.  The electronics and dynamics of the ink
> cartridge, however, limit you to generating dots at 300 per inch.
> On almost any paper, the ink wicks more than 1/300th inch anyway.
> 
> The method of depositing and fusing toner of a laster printer
> results in much less spread than ink drop technology.

In practice there is little difference in quality but more care is needed 
with inkjet because smudges etc. can happen.

> It doesn't take much investigation to see that the mechanical and
> electronic complement of a laser printer is more complex than
> inexpensive ink jet printers.  Recall also that laser printers
> offer a much higher throughput:  10 ppm for a laser versus about 1
> ppm for an ink jet printer.

A cheap laser printer does not manage that sort of throughput and on top of 
that how long does the _first_ sheet take to print? Inkjets are faster than 
you say and in both cases the computer often has trouble keeping up with the 
printer. (I have a 486/33 and a lot of drivers cannot keep up with the 
printer)

A sage said to me: "Do you want one copy or lots of copies?", "One", 
"Inkjet".
 
> Something else to think about is the cost of consumables over the
> life of the printer.  A 3000 page yield toner cartridge is about
> $US 75-80 at discount while HP high capacity (~500-1000 page yield)
> cartridges are about $US 22 at discount.  It could be that over the
> life cycle of the printer that consumables for laser printers are
> less than ink jet printers.  It is getting progressively closer
> between the two technologies.  Laser printers are usually desinged
> for higher duty cycles in pages per month and longer product
> replacement cycles.

Paper cost is the same and both can use refills. Long term the laserprinter 
will need some expensive replacement parts (consumables) and on top of that 
are the amortisation costs which favour the lowest purchase cost printer.

HP inkjets understand PCL so in many cases a laserjet driver will work if the 
software package has no inkjet driver. 

There is one wild difference between the two printers: a laserprinter is a 
page printer whilst an inkjet is a line printer. This means that a 
laserprinter can rotate graphic images whilst an inkjet cannot. Few drivers 
actually use this facility.
(there is also the matter of downloadable fonts and so on)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
Document_id: 54153
From: rwong1@ugly.UVic.CA (Richard  Wong)
Subject: Voice synth chips

Does anyone know where I can get some voice synthesis chips??
I am looking for something like the ones that do the time and date
stamp on answering machines.

Newsgroup: sci.electronics
Document_id: 54154
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Re: Lead Acid batteries & Concrete?

>   Why does a lead acid battery discharge and become dead (totally unuseable)
> when stored on a concrete floor?  

When will people learn!

The trouble is the ballast in the concrete and as every fool knows Ballast 
resistors are used to discharge batteries. Furthermore it is very silly to 
store the battery with the terminals downwards as you must have done to 
contact the ballast. 

Seriously: self discharge (the actual problem, as stated by others) does vary 
greatly with certain types and freaks show low self discharge. I have in 
fact seen ordinary automotive batteries which have effectively held full 
charge for > 2 years so it must be possible.

If your garage is heated, store the batteries somewhere cooler but above 
freezing (flat batteries freeze more easily). Occasionally charge it (once a 
month?) or even leave it on 'float' charge permanently (special charger, 
DON'T do this unless you know what you are doing, seriously dangerous).

Anouther point is the unsuitability of automotive batteries for things like 
electric mowers -- they are not generally designed to be repeatedly deep 
discharged and their life may be greatly shorted. Some early zero maintenance 
automotive batteries in fact responded to a full discharge with total failure 
shortly afterwards but modern ones are superb. (6yrs, 95000 miles and 
counting)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                

Newsgroup: sci.electronics
Document_id: 54155
From: alan@apple.com (Alan Mimms)
Subject: Re: UART needed (really BREAK detect)

In article <3402@tau-ceti.isc-br.com>, jimc@tau-ceti.isc-br.com (Jim
Cathey) wrote:
> 
> In article <alan-210493163447@17.129.12.26> alan@apple.com (Alan Mimms) writes:
> >Actually detecting a BREAK is done by watching for a "character" containing
> >all zero bits with the framing error resulting from its receipt.  This
> 
> True enough, but...
> 
> >means that the line stayed in the zero bit state even past the stop bit
> >time slot, which basically indicates a BREAK.  There is no special way to
> >detect BREAK that I have found other than this -- there's no magic signal
> >generated by UARTs, etc.
> 
> Zilog SCC:
> ---------
> 	RR0[7]:  Break Detect
> 
> This is a very popular part, but it has a number of quirks, especially
> in HDLC mode.
> 
> Signetics 68562 DUSCC:
> ---------------------
> 	RSR[2]:  Break Start Detect
> 	RSR[3]:  Break End Detect
> 
> Two of the bits in the Receiver Status Register.  You can enable an interrupt
> on either of these bits going high, too.  Also, only one NULL will be put
> in the FIFO per break detected.
> 
> This is simply the best serial chip I've ever worked with.  _Many_ less
> quirks than the SCC, which is IMHO second-best.  (Death to 8250 devices!)
> 

And I thought I knew a lot about serial devices.  Perhaps I should just
keep my big mouth shut.  Sorry.

Alan Mimms (alan@apple.com, ...!apple!alan)   | My opinions are generally
Portable Macintosh Software Group             | pretty worthless, but
Apple Computer                                | they *are* my own...
Art without engineering is dreaming.  Engineering without art is
calculating.
	-- Steven K. Roberts in "Computing Across America"

Newsgroup: sci.electronics
Document_id: 54156
From: cpuig@infoserv.com (Carlos M. Puig)
Subject: Re: Analog switches/Balanced Demodulators

msf@skaro.as.arizona.edu (Michael Fulbright) writes:

> I am trying to build a synchronous demodulator and I've hit a snag.
> In my application I want to be able to change the gain of an
> op amp amplifier from 1 to -1, controlable via a digital input.
> The most obvious way I've come up with is to use analog switches
> to adjust the gain of the op amp. The only analog switch I have
> experience with it the 4066. Unfortunately I want to switch an
> AC signal which goes from about -5V to 5V, and the 4066 is only
> for positive signals.
>

     I have recently used the 4066 to switch a bipolar signal.  I simply
ran the 4066 off a bipolar supply, +/- 8V in this case.   As long as your
analog input signal stays between the supply rails, the 4066 will work fine.
Of course, your control (logic) input must use -8V as the logic LOW and
+8V as the logic HIGH reference, so that either (1) all your driving logic
must be 4000 CMOS with the same bipolar supply or (2) you must provide
some kind of voltage level shifting circuit between the 4066 and the
control logic.  In my case, I was able to use the bipolar supply all the
way.


----
Carlos Puig, KJ6ST             cpuig@infoserv.com
San Jose, CA                   (408) 289-8174

Newsgroup: sci.electronics
Document_id: 54157
From: dmn@kepler.unh.edu (There's a seeker born every minute.)
Subject: flash LEDs with sound?



     I'm looking for a circuit that will flash an led on in response 
to the output from a walkman cassette player. How could I do this?
I don't want it just to turn on, I want it to 'strobe' once so to speak,
per every beep I put on a cassette tape. 

     Would it be better to use a circuit based on the volume of the beeps
on the cassette, or better for the leds to respond to a tone of a certain
frequency? Is there any easy way to do either of these? I'm looking for 
the simplest circuit possible. I guess what I'm asking for is some sort of
color organ, but not quite. Let me trt to explain again...


     I'm going to have a pattern of beats (or beeps) on a cassette tape.
So on the tape you'd hear:   beep! (pause) beep! (pause) beep! (pause)..etc. 
, with speed increasing as time goes on. I want to synchronize an LED (
probably two of them) with the beeps on the cassette tape. So the LED, with
each beep, would go on and off real quick, generating a strobe light sort
of effect. The rapidity of the beeps on the tape would in turn effect the
rapidity of the blinking of the LEDS. And if there was no sound on the tape
(except for background his), the LEDs would remain off. Please help!


  Thanks,

    Dana



Newsgroup: sci.electronics
Document_id: 54158
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: Re: Blue LED's

In article <Zw6F3B1w165w@inqmind.bison.mb.ca> Baden de Bari,
baden@inqmind.bison.mb.ca writes:
>Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???
Hosfelt
T-1 stock # 25-214
T-1-3/4   # 25-213
Both $1.29 - Vf 3.0..3.4, 470nm, 3mcd @ 10ma, Mfg Liton
Call 1-800-524-6464
Disclaimer - dont know these guys from a bar of soap, but the price
looks reasonable.

Newsgroup: sci.electronics
Document_id: 54159
From: rick@cs.sunysb.edu (Richard Spanbauer)
Subject: Re: Luser!

In article <1993Apr23.205257.10578@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for a very high speed 
>D/A converter (at least 8bits and 150MHz) for
>a research application. A paper in  the January
>issue of IEEE Solid-State Circuits mentions a 
>GaAs, 1GHz, 8bit DAC - anyone know where I can find
>such a thing? Even a somewhat slower Si DAC would
>do.
>	Needless to say, I have looked in all the
>conventional places (Vitesse, Motorola, National,
>etc. etc.). Any pointers would be appreciated.

	Think video.  Brooktree sells a whole line of DACs that can
	be used, normally for graphics applications, in either 50 or
	75 ohm systems.  For example, the BT468 can be had in speeds
	up to about 200 mHz, BT492 to 360 mHz, and 400 mHz with the
	BT109.  

>--- Seema Varma

					Rick Spanbauer, 
					SUNY/Stony Brook

Newsgroup: sci.electronics
Document_id: 54161
From: glynnet@zero.cypher.com (Glynne Tolar)
Subject: Re: Laser vs Bubblejet?

In article <735446880snx@black.demon.co.uk> tchannon@black.demon.co.uk writes:

>There is one wild difference between the two printers: a laserprinter is a 
>page printer whilst an inkjet is a line printer. This means that a 
>laserprinter can rotate graphic images whilst an inkjet cannot. Few drivers 
>actually use this facility.
>(there is also the matter of downloadable fonts and so on)
>
>  TC. 
>    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
>                                

I have a DeskJet 500 and I thought I'd give a little info.  The DeskJet 500 WILL
do landscape mode like the HP LaserJets.  I can't say if other inkjets do
though.  Also the DeskJet can do downloadable fonts ONLY if you buy a softfont
memory cart for it.  OH!  You said the LaserJet can rotate a graphic image!
Hmmmmm!  The DeskJet can only rotate text.  Nevermind!
 

Newsgroup: sci.electronics
Document_id: 54162
From: dmn@kepler.unh.edu (There's a seeker born every minute.)
Subject: blinking LEDs?



   Where can I buy blinking LEDs besides radio shack? 


  * Does anyone sell blinking LEDs with variable flash rate? (by voltage
    I guess) If so, what hertz (pulse) rate are they adjustable or set to?

     I'd like blinking LEDs that can be set for approx 5 hz, 10 hz, 
     15 hz, or 20 hz. Something like that... I'm interested in what's
     out there for flash rates. I like the idea of LEDs with flasher 
     circuits already in them. I hate soldering ICs in general. Guess I
     don't have a hell of a lot of patience. 


      Thanks,

         Dana


Newsgroup: sci.electronics
Document_id: 54163
From: mmoss@ic.sunysb.edu (Matthew D Moss)
Subject: How do you build neural networks?


Subject says it all, though I should specify that I'm looking for solutions
that DON'T require me purchasing specific chips, etc....

In other words, is there some sort of neural network circuit I could build
after a visit to a local R-Shack?
-- 
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Matthew David Moss		| Blessed are the pure in heart, for they     |
| INTERNET: mmoss@ic.sunysb.edu	| will see God.                               |
| BITNET  : mmoss@sbccmail	|                                 Matthew 5:8 |

Newsgroup: sci.electronics
Document_id: 54164
From: dhollman@phage.cshl.org ( CSHL)
Subject: Re: How to the disks copy protected.

I think a few things are being missed overall here... First of all, anyone
with a DOS manual can copy a disk, or copy anything (hidden files dont
go far if you are dealing with anyone who is not comletely DOS ignorant) off
of a hard disk. 'Professional' crackers aren;t interested in copying disks.
They are programmers who get some thrill out of going through unassembly
listings of programs to disable copy protection such as serial number
dialog boxes, volume label checks, and who knows what when it comes to
computer games. 
    
Those people are in the minority, however. In my experience with the world of
people and software, it seems that a good majority of people (say 80%) will
at some point copy a friend's program ("Gee, you really oughta try this") or
accept a copy. These are people who normally would buy a software package
or do without, but decided that just once it wouldn't matter.

The last thing is people who own or are responsible for more than one 
computer; most people aren't going to spend $150 * X# of computers for the
same software package.. they will just install it x# of times, especially
things like DOS upgrades.

-- 
|-----------------------------------------------------------------------------|
|    Are we having fun yet?                                                   |
|-----------------------------------------------------------------------------|

Newsgroup: sci.electronics
Document_id: 54165
From: <U19250@uicvm.uic.edu>
Subject: multiple inputs for PC

Can anyone offer a suggestion on a problem I am having?
I have several boards whose sole purpose is to decode DTMF tones and send
the resultant in ASCII to a PC.  These boards run on the serial interface.
I need to run * of the boards somwehat simultaneously.  I need to be able to ho
ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
PC inexpensivley, so that all can send data simulataneously (or close to it)?
Any help would be greatly appreciated!
Abhin Singla

Newsgroup: sci.electronics
Document_id: 54166
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: multiple inputs for PC

In article <93114.142835U19250@uicvm.uic.edu> <U19250@uicvm.uic.edu> writes:
>Can anyone offer a suggestion on a problem I am having?
>I have several boards whose sole purpose is to decode DTMF tones and send
>the resultant in ASCII to a PC.  These boards run on the serial interface.
>I need to run * of the boards somwehat simultaneously.  I need to be able to ho
>ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
>PC inexpensivley, so that all can send data simulataneously (or close to it)?
>Any help would be greatly appreciated!


Are the boards at all intelligent?  (I.e., run by microcontrollers?)  The
easiest thing would be to have another line that says that one of the
boards is talking to the PC.  When this line was true, the other boards
could all hold off and not send their data.  This isn't a perfect solution,
though, since you have to worry a little about making sure two boards don't
decide to talk at the _exact same time_.

Other than that, I think you will need to hook up each board to "something"
that speaks RS-232.  This actually isn't as hard (or as expensive!) as it
used to be, though.  Assuming the boards talk relatively slowly (9600 BPS
or slower), the PICs can coordinate things between themselves to multiplex
the data.  (This is really just forbicly adding the suggestion in the first
paragraph to your system.  And it assumes that each board doesn't talk more
than 1/8th of the time, of for very long, since a PIC isn't going to be
able to buffer more than, maybe 20-some bytes!)

You might want to check into the prices of multi-serial card for your PC,
though.  I recently bought a Boca Research 2x4 card (2 parallel ports, 4
RS-232 ports) for a very reasonable $85.

					---Joel Kolstad

Newsgroup: sci.electronics
Document_id: 54167
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Self-destructing copy protection on VHS tape?

In article <klp.735603389@quark> klp@doe.carleton.ca (Ka Lun Pang) writes:
>
>I borrowed a VHS tape from a friend and it has a warning in the begining saying
>that attempts to copy the tape will result in destroying the copy and the
>original. I found this unbelievable as playing and recording are two different
>processes. However, I've never seen this tape being sold anywhere so I don't 
>want to take the chance even it's small.
>
>Anyone has experience in this kind of self-destructing video tapes?
>

I have always thought that if I wanted to send the Police a tape with
a ransom demand on it, or send CNN a video tape to see if they wanted
to buy it, I would place a small magnet near the take-up spool so the
tape would be erased as it was played. Who would think to check?

John


Newsgroup: sci.electronics
Document_id: 54168
From: mcorbin@oucsace.cs.ohiou.edu (Max Corbin)
Subject: 1-bit A/D converter

Once upon a time, long long ago in this news group, someone
posted a schematic for a 1-bit A/D converter.  Well I just found a use
for the little monster.  Anyone out there still got this text file?
It had a flip-flop, a resistor and a cap, and a comparator/op-amp I 
think.  I would be extremely thankful to anyone who could mail me the 
schematic or post it to the news-group.



-- 
+-----+---\ +-----+ 	O O 	Beware the light at the end of the
| | | | -- >|  ---+	 +	tunnel.  It may be an oncoming Dragon.
+-+-+-+---/ +-----+     \_/
   M   	 D     C	 U      mcorbin@oucsace.cs.ohiou.edu

Newsgroup: sci.electronics
Document_id: 54169
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>
>That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.
>They didn't emit very much light...
>
Sorry Charlie...

I have a dozen, VERY blue LED's on my bench right now. They have
a clear plastic case and when lit, are absolutely BLUE. The hue
is sort of a "summer day cloudless sky blue" but make no mistake,
they are blue.

You can buy them from Digikey, Circuit Specialist, Jameco (I think),
LED-Tronics, Stanley Optoelectronics, and others. The current price
is around $2.50 each for small quantities. I will also be selling
them through my mail-order company in the near future (4 weeks).
Write for details if interested.

John




Newsgroup: sci.electronics
Document_id: 54170
From: ez019654@othello.ucdavis.edu (Victoria Milliron)
Subject: Re: How to the disks copy protected.

Hmmm...
  A possibility for the software registration conondrum would be to have the
distributor register the copy when the software was sold.  The clerk sticks it
in the store PC and asks for the buyers ID. Later, if pirated versions showed up they could be tracked to the original purchaser. In addition copies which were
sent to distributors/stores would have a vendor reg # or serial # in order to
track in store piracy.

Possible additional program security schemes would be:
1. having monthly password changes which necessitate user call in
   and registration. (inconvenient)
2. taking dire legal action on anyone caught (expensive)
3. encryption, crc check, self modifying code (limited effectiveness)
4. have an independent watchdog program in the installation/setup config or
   memory manager, etc. which would check the main program's crc. 
   (only as effective as above methods at best.)
5. have the above watchdog circulating as a virus which would trash cracked 
   copies of the program and/or the offenders hard drive. (risky, and probably
   illegal, certainly immoral)

my new ideas aren't terribly feasible to implement as presented, but I thought
if I threw them out people could think of variations that might be effective.
What is the problem with parallel port security keys? I haven't used anything
that had hardware key copy protection schemes, so I don't know what the
drawbacks are. I know the companies that make them claim they're uncrackable,
but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
so don't ask) and I had heard that it had parralel port keys.

vamilliron@othello.ucd.edu
-my apologies if I rambled, but vi inhibits my communication skills greatly.

Newsgroup: sci.electronics
Document_id: 54171
From: dasmith@sunburn.ec.usf.edu. (David Smith (GE))
Subject: Re: Laser vs Bubblejet?

Inkjet and Bubblejet printers are the same tech.  "Bubblejet" was trademarked
by Cannon and inkjet was by HP I belive.  I have seen both, and own a 
"bubblejet" (a Apple StyleWriter which has a cannon engine) with a 360 dpi
rated output.  The output is very good with quality paper, which is
very importaint.  Cheap paper gives bad results.  I use sealed paper and
the only differenc is that the ink is less dark than toner (I compaire
to the Apple Personal LaserWriter NTX), but then again the difference
is $300 to $1500 so....

--
/------------------------------------------------------------------------------
| David A. Smith               | "I like to skate on the other side of the ice"
| - dasmith@suntan.ec.usf.edu  | I Didn't do it, And I don't know anything  
| - smithd@eggo.csee.usf.edu   | either. USF better not know I'm here :) 

Newsgroup: sci.electronics
Document_id: 54172
From: belvilad@dunx1.ocs.drexel.edu (A. Belville)
Subject: Re: flash LEDs with sound?

In article <199304241405.AA11067@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:
>
>
>     I'm looking for a circuit that will flash an led on in response 
>to the output from a walkman cassette player. How could I do this?
>I don't want it just to turn on, I want it to 'strobe' once so to speak,
>per every beep I put on a cassette tape. 
>
>     Would it be better to use a circuit based on the volume of the beeps
>on the cassette, or better for the leds to respond to a tone of a certain
>frequency? Is there any easy way to do either of these? I'm looking for 
>the simplest circuit possible. I guess what I'm asking for is some sort of
>color organ, but not quite. Let me trt to explain again...
>
>
>     I'm going to have a pattern of beats (or beeps) on a cassette tape.
>So on the tape you'd hear:   beep! (pause) beep! (pause) beep! (pause)..etc. 
>, with speed increasing as time goes on. I want to synchronize an LED (
>probably two of them) with the beeps on the cassette tape. So the LED, with
>each beep, would go on and off real quick, generating a strobe light sort
>of effect. The rapidity of the beeps on the tape would in turn effect the
>rapidity of the blinking of the LEDS. And if there was no sound on the tape
>(except for background his), the LEDs would remain off. Please help!
>
>
>  Thanks,
>
>    Dana

	Try looking in a Magizine called Radio Electronics, May 1992 issue,
page 41.  There is a circuit for a Midi Light controller there.  

-=- Andy -=-

_______________________________________________________________________________
Andy Belville                          || It's taken me a long time, but I've
belvilad@dunx1.ocs.drexel.edu          || fallen in Love with a beautiful woman.
_______________________________________________________________________________

Newsgroup: sci.electronics
Document_id: 54173
From: tsjoit@htsa.aha.nl (T. H. Tsim)
Subject: Re: RAMs &ROMs with ALE latches (for 8051's)


>>In article <1qg98sINNokf@sheoak.ucnv.edu.au> jeff@redgum.ucnv.edu.au (j. pethybridge) writes:
>>>	Hello again,
>>> I asked this a year ago, but i am still looking.
>>> I am getting sick of having to use a HC373 

I didn't catch your posting one year ago, but I presume you like to leave out
an extra a-latch ? (I presume you allready know there is a '573 but that couldnt
be the question, could it ? ;-)

During my student-trainee project, I discouvered a nice device, it's a PSD301  
from Waferscale Integration. In one single (44 PLCC I think it was) package
it contained: ROM, RAM, I/O lines and a programmable addressdecoder...

As far as I can recall, it can be hooked directly with a MCS-51 series uP ... 
Neat huh ? But it needs programming before assembly, so it wasn't suitable
for my project. Perhaps usefull for you (future) plans ?


Greetings!


Newsgroup: sci.electronics
Document_id: 54174
From: victor@inqmind.bison.mb.ca (Victor Laking)
Subject: Re: Self-destructing copy protection on VHS tape?

klp@doe.carleton.ca (Ka Lun Pang) writes:

> 
> Hi folks,
> 
> I borrowed a VHS tape from a friend and it has a warning in the begining sayi
> that attempts to copy the tape will result in destroying the copy and the
> original. I found this unbelievable as playing and recording are two differen
> processes. However, I've never seen this tape being sold anywhere so I don't 
> want to take the chance even it's small.
> 
> Anyone has experience in this kind of self-destructing video tapes?
> 
> Thanks in advance.
> 
> --
> Ka Lun  Pang (a.k.a. Andy) - Lost between frequency and time on the unit circ
>                       email: klp@doe.carleton.ca 
>                                DoD# 0687


To put it bluntly, they are full of it.

Paying a tape is playing a tape.  There is no difference whether the 
output goes to a second VCR or to a TV.  (How the VCR or TV reacts to 
this signal is a different story - see messages pertaining to macrovision 
copy protection.)

In order for the tape to self-destruct, it would have to have circuitry 
of its own within the tape case.  The circuit would have to somehow 
magically determine what the output of the VCR is connected to.  The 
circuit would then have to have an erasing head to actually do anything.

It is a pretty lame scare tactic.  (I've seen something similar on a BBS.
When the SYSOP wanted to, he could have a message sent to the user's end 
saying that it is sending the code to format your HD.)


victor@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54175
From: <LEEK@QUCDN.QueensU.CA>
Subject: Re: How to the disks copy protected.

In article <C60DvH.FAn@ucdavis.edu>, ez019654@othello.ucdavis.edu (Victoria
Milliron) says:
>
>  A possibility for the software registration conondrum would be to have the
>distributor register the copy when the software was sold.  The clerk sticks it

That's kind of extra work that one cannot expect the store people to do.
IMHO it would be easier if companies sell their software as cheaply as
possible AND to sell the customers detail manuals (for the brain-deads)
, quick reference books, how to do books and videos, paid support hot line
(1-900 :).  For the registered purchasers, these can be part of their package.
I have seen many books to teach people how to use DOS, WP and other software.  I
I suspect either users can't read the manuals or they don't have manuals.
Either way, there is $$$ to be made.   BTW books are quite a bit more
expensive to reproduce than a $1 disk.

>What is the problem with parallel port security keys? I haven't used anything
>that had hardware key copy protection schemes, so I don't know what the
>drawbacks are. I know the companies that make them claim they're uncrackable,

With the popularity of Multitasking and pseudo multitasking systems
(eg. OS0.5, Windoze, Mack System 7), it is pretty easy to run a debugger
and figure out the protection schemes by disassembling/tracing/trapping
the application during run time.  Schemes like compressed software/
special loaders would be easy pray even to beginner hackers.

Hardware keys (unless well designed and *TOTALLY* transparent) is a
pain in the b*t.  We having using a piece of software under Windoze
that uses a hardware key.  The key interfers with the printer stuff
with other programs and often has to be unplugged for those software
to work properly.

>but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
>so don't ask) and I had heard that it had parralel port keys.

All the hacker has to do is to remove/modify code that communicate with
the port.

>vamilliron@othello.ucd.edu
>-my apologies if I rambled, but vi inhibits my communication skills greatly.

K. C. Lee
Elec. Eng. Grad. Student
OS0.5, Windoze, Mack are not trademarked...

Newsgroup: sci.electronics
Document_id: 54176
From: ree88132@zach.fit.edu (Keith Ledig)
Subject: needed: 120v 3watt fan

Can someone tell me where to find 120volt 3 watt 40 mA fans that
fit the standard computer mounting size )ie. 3 and 1/8 inch wide
and 4 inches diagonal from hole to hole (hole=where bolt or screw
goes through.  I have found higher (NOISY) fans that are 120 v
6 watt, but I need a quite fan.  I can use 12 volt as well, but
found just about all 12 volt fans to be noisy.  I also find that
the 120 v fans are not only quieter, but the blade shape has a lot
to do with it.  I have a dead fan that was quiet in it's day.  It
has long blades (like fan blades in a tturbo engine on a jet is
the only way I can describe it.  The dead fan is ETRI Model 126LH.
Actually it's not dead, it just makes a hideous rattle noise so
it's stealthy qualities are void.  Thanks.



Newsgroup: sci.electronics
Document_id: 54177
From: nelson@sun.soe.clarkson.edu (Russ Nelson)
Subject: Proposal: alt.fan.tesla

For discussion of Nikolai Tesla (who else??)

--
--russ <nelson@sun.soe.clarkson.edu> Businesses persuade; Governments force.

Newsgroup: sci.electronics
Document_id: 54178
Subject: PC BOARD Layout Help
From: <EH1QC@CUNYVM.BITNET>

Hi,  I have a few questions about laying out a PCB. I am using easytrax for dos
which is a great program. But what my question is When laying out traces what
thickness should they be? I am mainly designing low voltage low current boards
for micro controller apps. What should pad sizes be for resistors? I will be
turning to a commercial PCB maker to produce 1's of these boards and I was
wondering what is the minimum distance traces should be from each other. Well
any info would be great. Thanks.
                                                 Anton

Newsgroup: sci.electronics
Document_id: 54179
From: dws30@p1hdb01cd.amdahl.com (David Sharpe)
Subject: Re: Pink Noise


 Pink Noise and White Noise are equal amounts of all frequencies.  This
is in most cases around the 20-3.3K Hz range.  Pink/White are used to
adjust for room dynamics and stuff like that.  There are a few EQ's out
on the market that have Pink noise built in.  Most all from Audio
Control have them I know the C-101 does.  

Newsgroup: sci.electronics
Document_id: 54180
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Hi Volt from battery

In article <C5uFIG.1Dv@news.cso.uiuc.edu> martyj@mrcnext.cso.uiuc.edu (martin johnson) writes:
>I need a small battery powered hi voltage capacitive discharge supply to
>deliver ~6 joules at 250 volts...  the ubiquitous
>camera flash circuit is what I want, but I cant get mine apart without
>breaking it...

Charlie Brett's suggestion -- buy one of the disposable flash cameras, use
the film, then take the thing apart -- is a good one.  Note, though, that
you won't get a particularly precise voltage out of such a thing, and it
may be a single-point design that won't adapt well to off-nominal operation.

The things are easy to dismantle.  The key piece of information is that
when you advance the film on one of them, you are winding it *into* the
film cassette -- it is unwound from the cassette in the factory, when
the camera is made.  So no darkroom is needed for dismantling.  It's
standard film, so just take the cassette in for processing.

All the camera-store people do when you bring in one of the disposables
is rip it apart, toss the film cassette into the to-be-processed bin,
and throw the battery in one trashcan and the rest of the camera in
another.  If you take it apart yourself, you get an AA alkaline battery
(still with a fair bit of life in it) and all kinds of little bits and
pieces from the camera.

I expect you could even re-load and re-use the camera if you were really
determined.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 54181
From: camter28@astro.ocis.temple.edu (Carter Ames)
Subject: Lead ACid Batteries PART 2!!!


   I thought the first thread was hilarious, so here goes another post.

Some more background information on what has happened to my poor batteries.

  One year, I left the batteries in the garage.  The garage is Unheated.  
They were left in their places that they needed to be.  One in the riding
lawnmower (what a lux) and one in each motorcycle.  The battery in the 
riding lawnmower was about 3-4 years old, and one of the cycle batteries 
was new, and one was around 5 years old.  Upon spring time, I discovered
that all of the batteries were dead, and needed to be recharged.  They all
worked properly, except for the older ones, and they had to be replaced 
about halfway through the summer.  (they had originally been stored
in the garage, and I think I remember my dad charging them in spring)
  Last year, I decided to bring them in to the basement, which has two parts.
one is dirt and brick, and the other is concrete.  I brought in all three, and
discovered in the spring, (about 15 days ago) that not only were the batteries
dead, but when I put the charger on them, the charger said "HMMMMMMMM" and 
the amp-meter read around 1,000,000,000  (In other words, it was pinned)
the internal circut tripped, and I went on to the other batteries.  They
were the same.  
   Realizing that we still had 2 GIGANTIC sailboat batteries, also lead
acid, I decided to put the charger on them.  (these had been sitting for around 1 and a half years, on the brick and dirt part) and noticed that they only
needed a small charge, around 2 hours or so on trickle.  I tested them
by using them at the local gas station for giving jump starts, and they
worked fine for around 25 of 'em. 
  This leads me to believe one of several things.
     1) I bought really #$%tty batteries last year. (sorta true)
     2) the concrete has something to do with the discharge of the
        batteries.
     3) There was enough moisture to short out the terminals in the 
          room where the concrete is, 
     4) The dirt room was able to absorb the moisture in the air
         better than concrete.

(BTW, I can almost waterski in the dirt room)  

   Any other ideas?
    *could be the aliens, anything is possible.*
 

Newsgroup: sci.electronics
Document_id: 54182
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)

In article <7480241@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>It isn't the average temperature that is the key factor here, but rather
>which is better at transferring the heat out of the (presumably warmer
>than ground temperature) battery...

Uh, Bob, why is the battery warmer than ground temperature?  On the time
scales in question, and with the considerably reduced temperature swings
several feet underground, there isn't going to be any major temperature
difference between the battery and what it's sitting on.

>... Question - why does a concrete floor feel cooler than the 
>surrounding dirt when you place your hand on it?

Because the temperature of your hand, *unlike that of the battery*, is
determined by the balance between internal heat production and external
heat loss.  You're feeling the greater rate of heat loss from an object
(your hand) which is kept much warmer than its surroundings.  In the case
of an object with no significant internal heat production, this will
affect how quickly it comes into equilibrium with its surroundings (if
it started out not in equilibrium with them) but won't affect the final
temperature.

For the same reason, windchill affects whether you will freeze but not
whether water will freeze.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 54183
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: How to the disks copy protected.

In article <C5x75A.48H@ms.uky.edu>, msunde01@mik.uky.edu (Mark  Underwood) writes:
> In article <1r76sbINNkap@flop.ENGR.ORST.EDU> noeler@xanth.CS.ORST.EDU  
> (Eric Richard Noel) writes:
>> I hate hard copy manuals, and would rather have all docs online - *not*
>> because I want to copy the program, but because its usually faster and
>> and convenient than sifting through an old book I can't find.
> 
> Just MHO, but I prefer hardcopy books because you can have three or four  
> of them open spread across the bed (next to the desk in my dorm) and  
> reference them while using the program full-screen.  The Windows Help  
> things come closest to good on-line documentation I've seen, but they  
> generally aren't detailed enough and would probably take a LARGE amount of  
> space (even compressed) which is at a premium on my system . . ..  In  
> fact, the manuals are the primary reason I bought Borland's C++ compiler  
> instead of using the one the lab licensed (in the lab, of course).  I've  
> got a SHELF full of books to help me out when I'm stuck.  :-)   To each  
> his own . . . :-)
 
It is also much easier to scribble corrections on a hard-copy manual.
 
Jeff White     jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
Document_id: 54184
From: belvilad@dunx1.ocs.drexel.edu (A. Belville)
Subject: Circuit List (locations)


	Here is a list I get when I was combing through some microfilm one
day here at Drexel while completely board.  Most of these circuits are
pretty easy to constuct and can be done by a novice.
	This is basically some stuff that could prove useful to you without
having to sit down and either design or buy the stuff (not a good word, but I'm
tired right now).
	Hope you enjoy!

	If you have any additions send them to me and I'll add them to the list
.  They don't have to be from this particular magazine, they just have to be
interesting!

	RADIO ELECTRONICS

Year	Month	Page	Article Name and/or discription
----------------------------------------------------------------------------
92	April	31	Car Audio Amplifier (270 Watts)
	May	41	Midi Light Controller (Light control from music input)
		47	Solid State Relay 
		50	Digital Altimeter
	June	53	Electronic Thermostat
91	February43	Audio Sweep/Marker Generator (frequency response)
	April	43	Line Power from 12 volts (12 VDC -> 110 VAC) (40 Watts)
	June 	39	Electronic Compass
	August	55	Speaker Protector
	Sept.	33	Solid State Tesla Coil
	Oct.	39	Vocal Effects/Mixer
	Nov.	58	Music on Hold (Play music for someone who is on hold on
				the phone)
	Dec.	47	THD Analizer
		53	Battery Tool
		63	Electronic Fuse
90	Jan.	35	Acoustic field Generator
		45	Phone activated Audio Muting circuit
	Feb.	31	Frequency Probe
		37	Radar Detector Tester
	March	31	Universal Laboratory Power Supply
	April 	33	Morse/RTTY Detector
		43 	Capacitance Adaptor (Capacitance add on for a DMM)
		46	Solid State Wiper control
	May	37 	Universal Descrambler (for a TV)
	July	31 	Digital Dashboard (for a car)
	August	41	Digital Pressure gauge
	Sept.	33	Vocal Stripper (take the vocals away from music)
	Oct.	37	Rocket Altimeter (model rockets)
	Dec.	33	Benchtop Frequency counter
89	Jan	55	Carrier-Current Audio transmitter (audio through your
				house's wiring)
		62 	Plasma display globe
		70 	Advanced Control System
	Feb.	55	Carrier-Current Receiver
	March	51	Hi-Fi Audio Amp for House or Car (High Power)
	May	41	I-R Extender (extender for Infra-Red remotes)
	July	31 	Light beam communication
		38	Digital Capacitance meter
	Nov	39 	R-C Decade Box 
		43	Digital Compass
	Dec	37	Programmable Phasor Property Guard
88	July	41 	L-C Meter Part 1
	August 50	L-C Meter Part 2
87	Nov.	107	Electronic Combonation Lock
86	Sept	41	Stun Gun
	June	55	Click and Pop filter for your stereo (removes clicks and
				pops when you play old LPs)

-- From what I could see, you can order the circuit kits, finished or unfinished
	or you can order the parts that you can't get through a normal store

_______________________________________________________________________________
Andy Belville                          || It's taken me a long time, but I've
belvilad@dunx1.ocs.drexel.edu          || fallen in Love with a beautiful woman.
_______________________________________________________________________________

Newsgroup: sci.electronics
Document_id: 54185
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: How do you build neural networks?

mmoss@ic.sunysb.edu (Matthew D Moss) writes:.........
> In other words, is there some sort of neural network circuit I could build
> after a visit to a local R-Shack?
Marvin Minsky (hi there) writes of building "perceptrons?" in the 1950s using
motor-driven potentiometers to vary the weights. He reported that the circuits
worked even tho there were wiring errors. (Can you say ROBUST?)

Cadium Sulfide cells vary with light. CMOS or TTL gates provide the SIGMOID
somewhat-linear-yet-somewhat-limiter transfer function often used. 
Low power Schottky gates, and earlier gates, has about a gain of X8.
LEDs probably output enough light to easily control CdS cells, even at a
few mA. And paper with dark and light regions, controlled by pencil and
eraser, could also control CdS resistance. The very high input resistance of
CMOS gates may let you charge up 1uF paper/mylar caps to serve as memory.

Allen Sullivan

Newsgroup: sci.electronics
Document_id: 54186
From: then@snakemail.hut.fi (Tomi  H Engdahl)
Subject: Re: flash LEDs with sound?

In article <199304241405.AA11067@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:

>     Would it be better to use a circuit based on the volume of the beeps
>on the cassette, or better for the leds to respond to a tone of a certain
>frequency? Is there any easy way to do either of these? I'm looking for 
>the simplest circuit possible. I guess what I'm asking for is some sort of
>color organ, but not quite. Let me trt to explain again...

Look for information about 567 tone decoder chip. It is an easy to use
chip for detecting sound of certain frequency. You need only one
567 and some other componets for each led you want to control.
The chip can take the voltage levels, which the casette gives.
Radio Shack Archer Semiconductor Reference Guide gives good information
how to use that chip. It should be simplest way to go. The chip costs
something like 1-2 $.
--
Tomi.Engdahl@hut.fi  !  LOWERY'S LAW:
then@niksula.hut.fi  !  "If it jams - force it. If it breaks,
                     !   it needed replacing anyway." 
* This text is provided "as is" without any express or implied warranty *

Newsgroup: sci.electronics
Document_id: 54187
From: shiekh@ictp.trieste.it (Andy Shiekh)
Subject: 2% silver solder

  I have seen the existance of electronics solder with a 2% silver
content that seems to have good wetting and fatique reatings.
  Can anyone tell me why it is not used? (silver is not such an expensive
metal).


Andy

_____________________________________________________________________
Anwar Y. Shiekh           | I do not feel obliged to believe that the
International Centre for  | same God who has endowed us with sense, 
  Theoretical Physics     | reason, and intellect has intended us to 
Trieste, Italy            | forgo their use.
(shiekh@itsictp.bitnet)   |                        -- Galileo Galilei
_____________________________________________________________________


Newsgroup: sci.electronics
Document_id: 54188
From: jaeger.ka.sub.org!stephan (Stephan Jaeger)
Subject: Study as audio control engineer in the U.S.A.

Hi, folks out there !

I don't know whether I am in the right newsgroup, but I have a question.

If I am completely wrong here in this group, could you mail me the right name  
of the correct newsgroup ?

A friend of mine is studying electronics at the Technical University in  
Karlsruhe/Germany since one year.

He wants to know whether there are possibilities to study audio control  
engineering in the U.S.A. .

Does anybody know how to get information about these studies in the U.S.A. ?
Could you send me information like (e-mail)adresses of the universities,  
"quality" of these studies, and so on ?

Is it possible to e-mail the universities directly to get information ?

Do the universities send information via e-mail ?

Please could you answer via e-mail, because I don't read this newsgroup  
regularly.


Thanks in advance.

Stephan Jaeger
-- 
This space for rent.
Contact: Stephan Jaeger, Rheinstr.40, D-7500 Karlsruhe 21
	 +49 721 554293  stephan@jaeger.ka.sub.org

Newsgroup: sci.electronics
Document_id: 54189
From: selee@hpcc01.corp.hp.com (Lee Say Eng)
Subject: Re: microstepping

  You can try SGS L6217A, it can achieve 256 current level(microstep),
teere is a circuit in the SGS-THOMSON - " Smart Power Applicatio
Manual", order code for the manual is AMSMARTPOWERST/1

Best regards,

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| Moi,Siew Hong                 | email: shmoi@hpmalr65.mal.hp.com             |
| Hewlett-Packard Malaysia      |                                              |
| Bayan Lepas Free Trade Zone,  | Tel : 604-830-611     Fax : 604-843117       |
| 11900 Penang, Malaysia        |                                              |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Newsgroup: sci.electronics
Document_id: 54190
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C
From: MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham)

In <sasrer.735576383@cinnamon> sasrer@unx.sas.com writes:
> services we offered was an engine cleaning (remove all that oil BEFORE you
> sell the car...  ;-}). Unfortunately, we did not have a high pressure
> washer so we would use one several miles from the shop. On more than one
> occasion after washing the engine, it would not start as water would have
> gotten under the distributor (I would put a plastic bag around it to try and
> minimize this), around the spark plug wires, etc and it would be nearly
> IMPOSSIBLE to try and wipe all these areas down with a dry rag. The usual
> solution was to carry a can of WD-40, and when the car wouldn't start to spray
> all the likely areas and it would then start on the very first time.
> 
This definately gets the car going, but... WD-40 is highly flammable. Explosive
even in the right conditions, like a vapour sealed inside a distributor for
eg. And contact points tend to arc a tiny bit :)

I once saw the alternator/points cover blow completely off a motorcycle after
it had been restored to life with WD-40... fun to watch
(It was a Honda MR-50 minibike and the cover is only held on by large rubber 
grommet, so it wasn't really a big blast.)
       Graham B
PS As a more serious aside, it is apparently also conductive, so it is best 
to exercise caution with it around mains wiring.
                                                

Newsgroup: sci.electronics
Document_id: 54191
From: speth@cats.ucsc.edu (James Gustave)
Subject: Development tools for 8051?


Could someone point me toward a source (FTP/BBS/whatever) for development
tools for the 8051 microprocessor.  I specifically am looking for a Macintosh
cross-assembler/disassembler.  Also, is there a mailing-list dedicated to
discussing the 8051?  Thanks.

-- 
________________________________________________________________________________
james speth       email for pgp compatible public-key        speth@cats.ucsc.edu

Newsgroup: sci.electronics
Document_id: 54192
From: nagle@netcom.com (John Nagle)
Subject: Re: subliminal message flashing on TV

lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick) writes:
>Well, yes and no.  The _image_ can't be on the screen less than 1/30
>of a second, but a _mixture_ of images that's about 90% of the field
>that was supposed to be there and 10% of the 'subliminal' addition
>could be overlaid for one field, producing the same overall effect to
>our sluggish retinae of a discrete image projected for 1/300 second.
   
      This is a 1950s idea.  Supposedly, splicing in a frame of "Buy
popcorn" upped popcorn sales in a movie theatre.  Big flap at the time.
Congress involved.  Talk of making it illegal.  General agreement by
networks not to do it.

      A few years ago, some junior person at an advertising agency
re-invented subliminal projection and one commercial went out on tape
with single-frame messages.  It aired on a few stations, but a tech
at one station, previewing the tape, noticed a flicker and looked at
the tape frame-by-frame to find the "defect".  Big flap.  FCC notified.
Commercial pulled.  Press reports. Embarassed ad agency.  You could
probably find the press reports via Dialog or Nexis if you wanted.

      Now that everybody has VCRs, it's not likely that anybody could
get away with this on TV.

					John Nagle

Newsgroup: sci.electronics
Document_id: 54193
From: oscar@oscar.austin.ibm.com (Oscar R. Mitchell)
Subject: Development tools for 65C816?

In article <1ree36INNdmp@darkstar.UCSC.EDU> speth@cats.ucsc.edu (James Gustave) writes:
>
>Could someone point me toward a source (FTP/BBS/whatever) for development
>tools for the 8051 microprocessor.  I specifically am looking for a Macintosh
>cross-assembler/disassembler.  Also, is there a mailing-list dedicated to
>discussing the 8051?  Thanks.
>
>-- 
>________________________________________________________________________________
>james speth       email for pgp compatible public-key        speth@cats.ucsc.edu

I have the same question for any tools for the 6502 derivative processor
the 65C816 processor (designed by Western Design Center).

Thanks,
Oscar.
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Oscar R. Mitchell
  IBM Advanced Workstations and Systems Division
   RISC System/6000(tm) - Future Systems Hardware Architecture and Design Group
   Mail Stop: ZIP 9461
   11400 Burnet Road
   Austin, Texas   78758                               USA Phone: (512)823-0000
   IBM Tieline:  678-8513                              USA "FAX": (512)838-8561

   IBM VNet: OSCAR at AUSVM6
   IBM InterNet: oscar@oscar.austin.ibm.com

     USA InterNet: oscar@austin.ibm.com

#include <standard.disclaimer>   /* I DO NOT speak for IBM, only for MYSELF */
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-- 
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 IBM Corporation - Advanced Workstations and Systems Division
 RISC System/6000(tm) - Future Systems Hardware Architecture and Design Group
                  USA InterNet: oscar@austin.ibm.com

Newsgroup: sci.electronics
Document_id: 54194
From: DPierce@world.std.com (Richard D Pierce)
Subject: Re: Pink Noise

In article <34T302tW40N601@JUTS.ccc.amdahl.com> dws30@p1hdb01cd.amdahl.com (David Sharpe) writes:
>
> Pink Noise and White Noise are equal amounts of all frequencies.  This
>is in most cases around the 20-3.3K Hz range.  Pink/White are used to
>adjust for room dynamics and stuff like that.  There are a few EQ's out
>on the market that have Pink noise built in.  Most all from Audio
>Control have them I know the C-101 does.  

Wrong, wrong, completely wrong (and a little misleading, too).

White noise is random noise whose energy density is constant for a
constant bandwidth. That is, a 5 Hz wide band at 20 Hz will have precisely
the same amount of energy as a 5 Hz band at 20 kHz.

Pink noise is random noise whose energy density is constant for a constant
precentage bandwidth. Thus, a 5% wide band of noise at 20 Hz (whose
bandwidth is 1 Hz) will contain the same energy as a 5% wide band at 20
kHz (whose bandwidth is 1000 Hz wide). 

White noise is often used with spectrum analyzers that have constant
bandwidths, pink noise is used with audio-type real-time analyzers whose
bandwidths are centert-frequency dependent (often described as "1/3
octave" or "1/2 octave" or some such terminology).

White noise, relative to pink noise, has more energy at high frequencies
(at a rate equal to 3 dB per octave). Pink noise, relative to white noise,
has more energy at low frequencies (at a rate equl to, again, 3
db/octave).

-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |

Newsgroup: sci.electronics
Document_id: 54195
From: hubich@mercury.cs.uregina.ca (Chad D. Hubich)
Subject: Asynchronous Receiver Recommendations?


I am looking for a suitable UART for a project.  What I require 
is a stand alone device (i.e. not cpu controlled) which will 
receive 1200 baud RS232.  Also a nice extra would be a received 
data buffer.  Please reply with any info you have.

Thanks,
--
Chad D. Hubich		University of Regina	Dept. of Computer Science

Newsgroup: sci.electronics
Document_id: 54196
From: fmg@alpha.smi.med.pitt.edu (Filip Gieszczykiewicz)
Subject: Re: Self-destructing copy protection on VHS tape?

>klp@doe.carleton.ca (Ka Lun Pang) writes:
> 
> Hi folks,
> 
> I borrowed a VHS tape from a friend and it has a warning in the begining sayi
> that attempts to copy the tape will result in destroying the copy and the
> original. I found this unbelievable as playing and recording are two differen
> processes. However, I've never seen this tape being sold anywhere so I don't 
> want to take the chance even it's small.

	Greetings. There are 3 types of warnings on (US) tapes:

	1) A hologram is glued across the seam of the 2 halves of the
	   tape. The message usually reads, "If seal is broken, you must
	   buy this tape"

	2) The standard "MacroVision" warning, "Copies of this tape will
	   be unviewable"

	3) [your case] Extended message for the Average Consumer (tm) which
	   states that even attempting to copy the tape will destroy the
	   original. I don't believe you can sue them for misinformation
	   in cases like this :-)

	Take care.

	P.S. Of course, #3 is utter BS - but the Average Consumer (tm)
	     believes it. Heck, my mom once returned such a tape without
	     watching it... she was afraid that something might just 
	     happen :-)
-- 
/ Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
| All ideas are mine but they can be yours for only $0.99 so respond NOW!!!! | 
| I live for my EE major, winsurfing, programming, SCA, and assorted dreams. |
\ 200MB Drive - Linux has 100MB and MS-DOS has 100MB. MS-DOS is worried ;-)  /

Newsgroup: sci.electronics
Document_id: 54197
From: scottcr@wkuvx1.bitnet
Subject: Re: Cable TVI interference

In article <1993Apr23.191808.10835@rwwa.COM>, witr@rwwa.COM (Robert Withrow) writes:
> In article <1qf44aINNll@rave.larc.nasa.gov>, watson@nimbus.larc.nasa.gov (Catherine Watson) writes:
> 
> | I gave up after a year of
> | letters and phone calls.  I got the impression the FCC was powerless and it 
> | was up to the cable company to correct the situation.
> 
> Isn't there some *formal* action a citizen can take that *requires* the
> FCC to, at least, generate some paperwork?
> 
> -- 
>  Robert Withrow, Tel: +1 617 598 4480, Fax: +1 617 598 4430, Net: witr@rwwa.COM
>  R.W. Withrow Associates, 21 Railroad Ave, Swampscott MA 01907-1821 USA

For those who are interested, the FCC does indeed care about cable
leakage, particularly into the aviation nav band, or leakage that
is "causing interference to other services".

Part 76.611 details specific limits to acceptable leakage, and
measurement technique.  If you will clearly document your problem,
and measurement technique (a signal level meter with dipole is the
normal approach, remember to correct between measurement data and
microvolts per meter) and fax or mail the details to Mr. John Wong
Cable Branch, FCC 1919 M st. NW Wash DC, and a copy of your letter
to the local cable company, you will get results.  In fact the cable
company will probably start treating you much better when they realize
you have figured out how to get the FCCs attention.

What is important is to document your case as it relates to the
applicable rules.  However the cable company *is required* to
at least check out every complaint of leakage.  They must file
with the commission and maintain on premises a yearly measurement
report that details the results of leakage testing.

But remember, call the cable company first, and give them a
chance to work to correct the problem before contacting
the commission.

I am in the business of measuring cable system leakage via
the airborne method.

-- 
SCOTTCR@WKUVX1.BITNET aka Chris Scott- 
                 Telco: (502) 745-3834 

Newsgroup: sci.electronics
Document_id: 54198
From: tell@cs.unc.edu (Stephen Tell)
Subject: Re: subliminal message flashing on TV

In article <7480237@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> Hi.  I was doing research on subliminal suggestion for a psychology
>> paper, and I read that one researcher flashed hidden messages on the
>> TV screen at 1/200ths of a second.  Is that possible?

> Might
>even be a vector ("strokewriter") display, in which case the lower limit
>on image time is anyone's guess (and is probably phosphor-persistence limited).

Back in high school I worked as a lab assistant for a bunch of experimental
psychologists at Bell Labs.  When they were doing visual perception and
memory experiments, they used vector-type displays, with 1-millisecond
refresh rates common.

So your case of 1/200th sec is quite practical, and the experimenters were
probably sure that it was 5 milliseconds, not 4 or 6 either.

>Bob Myers  KC0EW >myers@fc.hp.com 

Steve
-- 
Steve Tell       tell@cs.unc.edu H: 919 968 1792  | #5L Estes Park apts
UNC Chapel Hill Computer Science W: 919 962 1845  | Carrboro NC 27510
Engineering is a _lot_ like art:  Some circuits are like lyric poems, some
are like army manuals, and some are like The Hitchhiker's Guide to the Galaxy..

Newsgroup: sci.electronics
Document_id: 54199
From: mudayja@wfu.edu (Jeffrey Muday)
Subject: Re: How to the disks copy protected.


This has been an interesting thread to follow... and obviously this group
wasn't intended as a forum for the discussion of piracy... Has anyone seen
any estimates of the lost revenue due to pirates?  I was wondering if
piracy is more rampant in Home or Corporate computing environments.  I would
tend to think that business environment "piracy" is the major contributor to
this form of lost revenue.  So many companies will purchase a few copies of a
software package and then employees will internally distribute them as if they
owned a site-license!  What do you guys think?

Newsgroup: sci.electronics
Document_id: 54200
From: jeh@cmkrnl.com
Subject: Re: Blue LED's

In article <C5yqDE.Cq0@ecf.toronto.edu> gladman@ecf.toronto.edu (GLADMAN AVIV) writes:
>That's why you
>don't find blue LEDs or, for that matter, some other colour of LEDs. That
>is not to say that blue LEDs can't be found.  I've seen 'blue' LEDs sold,
>but they were just your typical visible light LED in a blue plastic covering.

No.  The blue LEDs sold down the street are in milky-white plastic.  

And, fyi, putting a filter on a "typical visible light LED" (presumably meaning
a non-blue one) won't produce blue light.  A filter can only block light, it
can't generate wavelengths that aren't there to start with.  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet:  jeh@cmkrnl.com  Uucp: uunet!cmkrnl!jeh  CIS: 74140,2055

Newsgroup: sci.electronics
Document_id: 54201
From: pat@fegmania.wustl.edu (Pat Niemeyer)
Subject: Re: Self-destructing copy protection on VHS tape?

schuch@phx.mcd.mot.com (John Schuch) writes:

>I have always thought that if I wanted to send the Police a tape with
>a ransom demand on it, or send CNN a video tape to see if they wanted
>to buy it, I would place a small magnet near the take-up spool so the
>tape would be erased as it was played. Who would think to check?


That is an exceptionally cool idea.
Would it work?

How strong a field is needed?
Anyone?



Pat@fegmania.wustl.edu  -------------------------------------------------------
  #   #   
   C C    "Revely, Nancy Sinatra, Christmas Carols... a kind of stereo hell" 
  ( " )                                      -- Chris Buery, ABC News
    `
---------------------------------------------------------------- (314)-851-0993

Newsgroup: sci.electronics
Document_id: 54202
From: haunma@saturn.wwc.edu (Mark Haun)
Subject: Re: 1-bit A/D converter

In article <1993Apr24.201422.25682@oucsace.cs.ohiou.edu> mcorbin@oucsace.cs.ohiou.edu (Max Corbin) writes:
>Once upon a time, long long ago in this news group, someone
>posted a schematic for a 1-bit A/D converter.  Well I just found a use
>for the little monster.  Anyone out there still got this text file?
>It had a flip-flop, a resistor and a cap, and a comparator/op-amp I 
>think.  I would be extremely thankful to anyone who could mail me the 
>schematic or post it to the news-group.

Hmmm... how about a piece of copper wire?  0 to 5V input range, standard
TTL output, instantaneous conversion time!

[ (-:  for the humor impaired ]


     Mark A. Haun       | INTERNET: haunma@wwc.edu
   252 Sittner Hall     | Amateur Radio KJ6PC
College Place, WA 99324 |
   +1 509 527 2297      |

Newsgroup: sci.electronics
Document_id: 54203
From: schmidt@auvax1.adelphi.edu
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

In article <1993Apr25.094202.3978@lugb.latrobe.edu.au>, MATGBB@LURE.LATROBE.EDU.AU (BYRNES,Graham) writes:
> In <sasrer.735576383@cinnamon> sasrer@unx.sas.com writes:
>> services we offered was an engine cleaning (remove all that oil BEFORE you
>> sell the car...  ;-}). Unfortunately, we did not have a high pressure
.........
>> 
> This definately gets the car going, but... WD-40 is highly flammable. Explosive
> even in the right conditions, like a vapour sealed inside a distributor for
> eg. And contact points tend to arc a tiny bit :)
> 
> I once saw the alternator/points cover blow completely off a motorcycle after
> it had been restored to life with WD-40... fun to watch
> (It was a Honda MR-50 minibike and the cover is only held on by large rubber 
> grommet, so it wasn't really a big blast.)
>        Graham B
> PS As a more serious aside, it is apparently also conductive, so it is best 
> to exercise caution with it around mains wiring.
>                                                 
I, some years ago, almost became a victim of this.  Squirted a fair amount in
an old model 15 Teletype which was acting up, then turned it on.  The eruption
when the motor starting contacts broke was mighty spectacular... I almost got
my eyebrows singed, the plastic (old ones had safety glass) cover over the
platen, etc flew across the room, and several people in the room almost had
heart attacks.  Beware the explosive properties of WD40 vapor.

-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218
Adelphi University                 |       Evenings (516)877-6400
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
Document_id: 54204
From: schmidt@auvax1.adelphi.edu
Subject: Re: subliminal message flashing on TV

In article <nagleC6213E.DsE@netcom.com>, nagle@netcom.com (John Nagle) writes:
> lihan@ccwf.cc.utexas.edu (Bruce G. Bostwick) writes:
>>Well, yes and no.  The _image_ can't be on the screen less than 1/30
>>of a second, but a _mixture_ of images that's about 90% of the field
>>that was supposed to be there and 10% of the 'subliminal' addition
>>could be overlaid for one field, producing the same overall effect to
>>our sluggish retinae of a discrete image projected for 1/300 second.
>    
>       This is a 1950s idea.  Supposedly, splicing in a frame of "Buy
> popcorn" upped popcorn sales in a movie theatre.  Big flap at the time.
> Congress involved.  Talk of making it illegal.  General agreement by
> networks not to do it.

More than Talk:  From the FCC Rules:  73.4250 Subliminal Perception:

(a) See Public Notice, FCC 74-78, dated January 24, 1974, 44 FCC 2d, 1016; 39
Fr 3714, January 29, 1974.
(b) See FCC Information Bulletin, "Subliminal Projection" (sic, at least in my
rules service copy of the rules), dated November 1977.

Since I don't have either old copies of the Federal Register or the Information
Bulletin around, I can't tell you what you can't do on TV ( or radio) but I
seem to remember this being an unnecisarily hot subject in the late '70s. 

Practically speaking, I dont have too much trouble seeing the one frame edits
in MTV promos,  badly scratched or torn single frames in films and such, but
maby that's just because the contrast between the single frame and the
surrounding material was significant.  I never believed in the one-frame type
of SP being real.  

On the other hand, the Coca-Cola or Brand (insert desired name here) beer cans
conveniently placed so the brand name is visible in the movie you just watched,
that's another story, and if your TV station or network was paid by the beer
company for the privilege of doing that, there has to be a "Promotional
Consideration paid by ...) or similar message included with the program; but if
the TV station bought the movie already edited that way from the film company
and didn't get any of the payment for "brand visibility" that the film company
got, then they don't have to run the message.
> 
>       A few years ago, some junior person at an advertising agency
> re-invented subliminal projection and one commercial went out on tape
> with single-frame messages.  It aired on a few stations, but a tech
> at one station, previewing the tape, noticed a flicker and looked at
> the tape frame-by-frame to find the "defect".  Big flap.  FCC notified.
> Commercial pulled.  Press reports. Embarassed ad agency.  You could
> probably find the press reports via Dialog or Nexis if you wanted.
> 
>       Now that everybody has VCRs, it's not likely that anybody could
> get away with this on TV.
> 
> 					John Nagle
-- 
*******************************************************************************
John H. Schmidt, P.E.              |Internet: schmidt@auvax1.adelphi.edu
Technical Director, WBAU           |Phone--Days     (212)456-4218
Adelphi University                 |       Evenings (516)877-6400
Garden City, New York 11530        |Fax-------------(212)456-2424
*******************************************************************************

Newsgroup: sci.electronics
Document_id: 54205
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: 77P20 programmer

Having vainly looked for devices capable of dealing to the NEC 77P20
DSP chip which dont require taking out a mortgage, i decided to roll
my own. Not a difficult task for an 8751, given that all the timing
relationships are set out in the databook. One thing bothers me, that
is the accursed 50ms 21 volt Vpp pulse. Sure, a little buck step-up
converter can achieve this (in what is otherwise an all 5 volt widget)
but i know latterday eproms dont need nearly this pulse length.
Q : has anyone come up with a more efficient programming algorithm
which is failsafe ?
cheers
Mike.

Newsgroup: sci.electronics
Document_id: 54206
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

wb8foz@skybridge.SCL.CWRU.Edu (David Lesher) writes:
: 
: (Why do ALL  postings from bnr seem to have bogus addresses? 
: Both 
: 	gstovall@crchh67.NoSubdomain.NoDomain
: and 
: 	gstovall@bnr.com
: bounce....
: 
: This makes it rather difficult to reply....)

They go through UUNET. This is often the problem - as UUNET often has
problems with return paths.

... deleted ...

: Oh, and most importantly, no amount of transmitted RF, short of a
: transmitter the size of small house, is likely to cause the equipment
: failures you describe. So you are looking at two different problems.

Yep.

Bill

Newsgroup: sci.electronics
Document_id: 54207
From: Sean_Oliver@mindlink.bc.ca (Sean Oliver)
Subject: descrambling channels

I live up in British Columbia, Canada.The cable company I use is called
Rogers Cable. Does anyone know of their scrambling techniques, and ways of
getting
around them? Any suggestions of what they might use?

--
+--------------------------------------------+
| Sean Oliver                                |
| Internet Address: a8647@MINDLINK.BC.CA     |
|                                            |
| Mindlink! BBS (604)576-1412                |
+--------------------------------------------+


Newsgroup: sci.electronics
Document_id: 54208
From: shorty@nevada.edu (DAVID HAAG)
Subject: Re: Pink Noise

In article <34T302tW40N601@JUTS.ccc.amdahl.com> dws30@p1hdb01cd.amdahl.com (David Sharpe) writes:
>
> Pink Noise and White Noise are equal amounts of all frequencies.  This
>is in most cases around the 20-3.3K Hz range.  Pink/White are used to
>adjust for room dynamics and stuff like that.  There are a few EQ's out
>on the market that have Pink noise built in.  Most all from Audio
>Control have them I know the C-101 does.  
 

With regards to what you wrote, how does one "adjust for room dynamics 
and stuff like that"?  I asked a professor that question just
last week and he didn't really know himself.  Since pink noise is believed
to be due to surface states (say, the surface of the Silicon where there's
a lack of a covalent bond) that act as "traps" to nearby elecrons, and since
this happens at low frequencies (because at high frequencies they aren't
able to "trap" electrons), how do you compensate for that?  It seems to me
that you wouldn't be able to compensate for pink noise.  I have seen the
"pink noise" feature, however, on many EQs, and I was wondering
how they are suppose to compensate for noise when pink noise is not due to
"man made noise" like power lines, crosstalks, coupling, etc.  If you have
any information about this, it would be appreciated.  Hope this didn't sound
too drawn out.  Thanx.
 
                              - David (shorty@helios.nevada.edu)








Newsgroup: sci.electronics
Document_id: 54209
From: irsman@iastate.edu (Ian Schmidt)
Subject: Re: Development tools for 65C816?

In article <C6217x.2xoL@austin.ibm.com> oscar@oscar.austin.ibm.com (Oscar R. Mitchell) writes:

[request for WDC65c816 Mac cross-development stuff]

Apple themselves sells a 65816 cross-developer for the Macintosh called 
'MPW IIgs' (it's intended for use with the Apple IIgs computer, which uses
the '816).

> Oscar R. Mitchell

-- 
        Ian Schmidt - Two Meg Software: irsman@{iastate.edu | aol.com}
"I will choose a path that's     | Author of AudioZap, MODZap, and more.
 clear: I will choose free will" | Co-author of SoundConvert and DeskTracker.
 - N. Peart, 1980                | Coder and Musician for the GS<>IRC.

Newsgroup: sci.electronics
Document_id: 54210
From: fuchs@tsar.princeton.edu (Ira H. Fuchs)
Subject: Removing battery corrosion

Is there a readily available solvent that does a good job at removing the  
corrosion/encrustation that collects on the battery terminals (usually the  
cathode) when using alkaline batteries (or more accurately, when NOT using  
them for a long time)? 

Newsgroup: sci.electronics
Document_id: 54211
From: jsm@shade.Princeton.EDU (John Scott McCauley Jr.)
Subject: how to get rid of flyback whine?

I recently took apart my color Sony TV to clean the volume pushbuttons and
when I put the beast back together, the flyback whine got much louder.

Is this easy to fix? Which part is resonating? I have heard rumors of a
spray that will fix the noise.  Is this a simple thing for a TV repairman
to fix?

	Thanks,

		Scott

Newsgroup: sci.electronics
Document_id: 54212
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: ATARI 2600 Processors

In article <1r7e14$l2c@sunb.ocs.mq.edu.au> ifarqhar@laurel.ocs.mq.edu.au (Ian Farquhar) writes:
>In article <1993Apr21.081317.599@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:
>>The Atari 2600 used a 6502 CPU, just like their entire 8-bit line
>>(400, 800,1200,1400, 1440, 130xe, 65xe computers, as well as the 5200
>>game machine). 
>
>Wrong, it has a 6507.

Sorry Ian, I haven't toyed with it in several years. I haven't seen
the insides in quite a few years. I just saw the post lagging for
quite a few days, and thought I'd toss in my $0.02. I assume the 6507
was functionally similar to the 6502 (was it also made by MOS
Technologies?). I really am more versed in the (6502 based) Atari
computers. The 2600 came later on.

>
>>The 2600 had some extra ASIC chips that were basically
>>modified graphics chips and PIA's for the joysticks. 
>
>It had one custome chip (not an ASIC in the sense that word is now understood):
>the TIA (sometimes known as the 6526, although most other manufacturers list
>that as the CIA complex interface adapter.)  TIA stands for Television
>Interface Adapter, and it handles sound, paddles and the minimal video hardware
>the 2600 possessed.

In the Atari computers, the "CIA" chip you refer to sounds an awful
lot like the CTIA (Color Television Interface Adapter) chip used in
the early models. Later Atari upgraded this to the GTIA (Graphics
...). Other colorful literature stated that the GTIA might have stood
for "George," the developer of the chip.

>
>There was also a standard 6532 RAM, I/O, Timer (RIOT), plus a voltage
>regulator and (if memory serves) a 555 timer.  That's all.
>
>>Later model 2600
>>might have incorporated many of the chips into one ASCI, as the weight
>>of the machines and part count decreased a lot over the years.
>
>Not according to the servicing documentation I have here.  The 2600 did not
>change intenally very much at all.

Funny, I had an old and new model. The old one was SIGNIFICANTLY heavier.

>>Additionally, I think the 2600 used 2K, 4K, and up to 8K of ROM for
>>their games. 
>
>ROMS were mapped into the upper 4K of the 6507's address space.  2K and 4K
>games were fine, but later 8K and 16K games needed bank switching.  Atari
>(and others) made much of these "huge" cartridges.
>
>>I have no idea how much RAM it had to work with, but I
>>would hazard a guess of 2 or 4K RAM. 

Sorry, I am way out of line here. My first microcontroller I built was
a MC68701 based chipset with 128 bytes onboard. That was not easy to
work with (in addtion to a small 2K on-board EPROM).

>Wrong, it had 128 bytes of RAM from the RIOT.  This was multiply mapped into
>both page 0 (pseudo-registers) and page 1 (stack), and also throughout the
>bottom 4K of memory.  TIA registers also sat in this address space.
>
>As 128 bytes of RAM was somewhat limiting, some later cartridges also carried
>RAM themselves, which was interesting as Atari had provided no write line
>to the cart.  This was managed by mapping the reads from RAM into one address
>range, and the writes into another, but all the time this scheme ate into
>the *very* scarce ROM address space.
>
>							Ian.



Newsgroup: sci.electronics
Document_id: 54213
From: rcstage1@urc.tue.nl (Guido Klemans)
Subject: Re: How to the disks copy protected.

In article <C60DvH.FAn@ucdavis.edu> ez019654@othello.ucdavis.edu (Victoria Milliron) writes:
>From: ez019654@othello.ucdavis.edu (Victoria Milliron)
>Subject: Re: How to the disks copy protected.
>Date: Sat, 24 Apr 1993 22:16:29 GMT
>Hmmm...
>What is the problem with parallel port security keys? I haven't used anything
>that had hardware key copy protection schemes, so I don't know what the
>drawbacks are. I know the companies that make them claim they're uncrackable,
>but I've seen cracks of AutoDesk 3d-studio floating around (I don't have one
>so don't ask) and I had heard that it had parralel port keys.

If you put another computer on the port instead of the key, you can hack 
them by reading what happens. So I've been told, I've never seen this done 
but I think it's possible. You'd need some hardware knowledge and some 
software to read the port!


>
>vamilliron@othello.ucd.edu
>-my apologies if I rambled, but vi inhibits my communication skills greatly.

-------------------------------------------------------------------------------
Guido Klemans

Internet: rcstage1@urc.tue.nl                  valid until 16 may 1993

-------------------------------------------------------------------------------

'Listen very carefully, I will say this only once.'  Michelle of the resitance

-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54214
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

dplatt@ntg.com (Dave Platt) writes:
: 
: >What kind of power must he be putting out to cause the effects?
: >The affected equipment is about 100 feet from the road...
: 
: Might be a couple of hundred watts, from the sound of it.  Kicking sound
: out of the TV and stereo speakers by direct RF rectification requires a
: mighty strong carrier!  [I've heard of linears so powerful that
: triggering them while the car was idling, would stall the engine by
: pulling down the battery voltage.]

It would take a lot more than that. It sounds like the radio equipment is
actually not shut completely off - but just goes to a standby situation.

I suspect that the stories are just that, stories.  The voltage can only
be sucked down so far instantaneously. When you try to jumpstart someones 
car, when your vehicle is at idle, does your car stall? No, the other car
just does not crank well.  Now, the engine might stall because the idle
was too low to start with. When the extra current is drawn, the idle speed
will drop - as the alternator loads down the engine to compensate for the
increased amperage requirement.

: >Is resolution of this problem a matter for the power company, the fcc, or both?
: 
: Ultimately it's likely to be your problem to resolve, I'm afraid.  The
: FCC is so understaffed that they don't pay much attention to citizen
: complains about RFI (or so I've heard)... they'll just send you a
: pamphlet describing how you can apply corrective measures.
: 
: Talking to the power company might help - they might be able to install
: filtering devices at your service panel (or recommend a type which you
: could have installed by a licensed electrician).

A transmitter is not going to be affecting house power. If surges are
occurring there, it is due to another cause - not a transmitter.

: Unfortunately, there's a fair chance that enough signal is being picked
: up by your house wiring that a simple service-panel filter won't
: suffice.  You may need to install heavy-duty RFI filters at the power
: connections of your affected equipment.

It is probably not that much of a problem. Often - toroid coils on the
power leads will solve that part of the interference problem. It will
not solve internal equipment deficiencies.

: If the problem occurs regularly, you may need to "stake out" the street
: in question, and watch for trucks or cars with big antennae driving by
: at the time interference occurs.  If you can identify the vehicle which
: is transmitting, you may be able to contact its owner and complain.

It is probably not the transmitter that is at fault. If the person is an
amateur, then he/she will probably be willing to help - if you explain
that the person is causing interference.

Bill

Newsgroup: sci.electronics
Document_id: 54215
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

drand@spinner.osf.org (Douglas S. Rand) writes:
: 
:    Hams can legally run up to 1500 watts.  It is very unlikely, however,
:    that a ham would be running that kind of power from a car.  Ham rigs
: 
: Not possible either.  You'd need about a 300 amp alternator for
: just the amplifier.  I can just see it.  You need to slow
: down on a downgrade,  so you hit the push to talk button.

Well - 100+ amps anyway. Transmissions are generally for a short interval.
The battery would supply the rest. Of course, if you transmitted too much,
you would run the battery down.

It really would not be that much of a brake.  Even at 50% efficiency, 1500
watts would only consume 4 horsepower.

Bill

Newsgroup: sci.electronics
Document_id: 54216
From: hugo@cats.ucsc.edu (Hugo Calendar)
Subject: How universal are phones these days?


I'm wondering if I can tote my American touch tone phone around with me
to Sweden and Germany.  It's DC powered, and I can buy a special adapter
for that in Europe.  The question is if the general electronics work
the same.  I can buy a different wall plug and refit it (I'm sure I'd
have to), but would that do the trick?

Thanks,
Hugo

Newsgroup: sci.electronics
Document_id: 54217
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

brian@ucsd.edu (Brian Kantor) writes:
: While it's possible that it's a ham radio transmitter that you're
: hearing, it isn't likely - every bit of signal that doesn't go out the
: antenna is wasted, as far as a ham is concerned, and most hams are

It is the radiated signal that would cause the problem.

: technically competent to ensure that they don't waste any signal if they
: can possibly avoid it.  To get their ham license, they had to pass a
: government exam that tests them on that point, among others.
: 
: However, you could be hearing a radio transmitter for sure - there are
: lots of other services where the operators AREN'T required to be
: technically competent - Citizens Band ("CB"), for example.

There is nothing in the Amateur Radio Tests that requires an technical
competence at all. It is a simple matter to memorize all the questions
and answers.  However, that said, most Hams that I know do spend quite
a bit of time gaining some technical skill.

: Listen to the interference.  If you hear voices clearly, it almost
: certainly ISN'T ham radio, and might well be CB.  If you can record a

Don't count on that.

: bit of it, you could take the tape over to a local ham operator's house
: and ask him for his opinion of what you're hearing.  Most communities

You cannot do that legally. However, you can ask a ham over to listen.
If the interference occurs at a specific time each day, then it would
be possible to do such scheduling.  If nothing else, you could invite
the ham over to transmit from your driveway, to see if he interferes.
If he does, then you probably need to have your equipment worked on to
make it immune to rf interference.

: have a ham radio interference committee whose members are most willing
: to help you resolve interference complaints.  Look in the phone book, or
: ask at the local ham radio store, or call the FCC for contact info.

The FCC may, or may not, have such information. They have enough to do
without getting calls for such information. If nothing else, call your
city offices or police department (general business number). They should
have the name of a local ham contact.

: If it's a ham, he's more than likely willing to help get rid of the
: problem.  After all, it would be his signal he's wasting.  If it isn't,
: the interference committee or the FCC may be able to suggest solutions.

See above - your concept of wasted signal is erroneous. If his rig is
transmitting properly, then the chance of interference (with the exception
of harmonic television interference) is the greatest - since he is putting
out the strongest signal.

: It is unfortunately the case that a transmitting station that is
: operating perfectly legally could possibly cause intereference to a
: piece of consumer audio or TV equipment just because the manufacturer of
: the consumer equipment cut corners on one little section of the device
: that wouldn't affect one person in a thousand, but which bites you.
: Often that can be remedied for just a few pennies by a knowledgeable
: person, perhaps even the person operating the transmitter you're
: hearing.

Unfortunately, most consumer equipment is succeptable - it is all poorly
designed.

: (BTW: hams are ALLOWED amplifiers; CB isn't.  "illegal ham amplifier"
: doesn't compute.)

It does, but not for a mobile radio. There are very few mobile rigs that
could power a 1500 watt amplifier.

Bill

Newsgroup: sci.electronics
Document_id: 54218
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: Laser vs Bubblejet?

	Just thought I would add $0.02 to DeskJet thread. I got my
first one in college about 5 or so years ago.

	I've been a happy HP user of the DeskWriter for Macintosh for
past 5 years. I got one just a few months after their release. And I
got software revision 1.0a (now I'm up to rev. 3.1. Our family (sister
and father) have each purchased their own DW's after seeing mine go
for one year unscathed (their stuck to their trusty ImageWriter II's).
The original DW has gone for 5 years at moderate personal use. I would
say that it has gone through at least 15,000 sheets, and around one
(small) ink cartridge every 3 months or so.

	My brother might take this DW now (I'm probably gonna give it
to him), and I am looking to upgrade to a color DW. The chief
advantages/disadvantages I've found over the years are:

Advantages:	Quick (2-3 ppm), Quiet (roomate can sleep while it's
printing), AppleTalk Networkable (unfortunately the original wasn't,
so look out if you buy used. I rewired our home with phonenet
AppleTalk connectors, and while home, we can all use my dad's one
DW!), and cheap (now run ~$300). BTW, you can upgrade older DW's to
color or for appletalk, I dunno if HP still does the upgrades, but I
received many offers (I just didn't ned it however). Also, crisp
laser-quality output is a wonder (used to really impress those
ImageWriter Dot-Matrix people so much so, that I had to charge $0.25
per sheet to stop my college dorm neighbors from bothering me at all
hours of the night....)

Disadvantages.	Ink used to be hard to find, and wasn't cheap, and
wasn't originally water-proof. While HP has done wonders with the ink
(I dunno if it's still toxic), it is still subjet to smearing and
running (if you run around in the damp Boston rain, and get your
bookbag completely soaked). Ink now runs about $14-$15 for small carts
(I get mine from Elek-Tek in Chicago, I think they're now down to
$12). The ink carts used to say they're dated for only 6 months, but
I don't think they say so anymore. We stick to a 4 month supply (of
about 3 carts). We use cheap Hammerhill Laser Print paper (after
fooling for a long time. Laser/Xerox paper is also good). Smearing
doesn't happen, unless you have a brand new ink cart and you grab the
paper and smudge it all over as soon as it comes out of the machine.
Other disadvantages are : No Postscript (this can be an advantage in
speed, usually). Ways around this are Ghostscript or Freedom of Press
software solutions. I bet HP probably has a PS prototype inkjet, but
they won't release it for fear of hurting LJ sales.

In the end, the primary advantages of laser are true postscript
(unless you go for cheap lasers), and fused toner (no smearing, even
when soaking in water). Lasers are slightly sharper, but the only
instance where I needed precise layouts was Printed Circuit Board
Transparencies for PhotoEtching. I found a Textronix color Phaser
Postscript (Thermal Wax Transfer) to work the best to make PCB
negatives directly onto a transparency.

Well, hope my babbling has helped.
-squish@endor.harvard.edu


Newsgroup: sci.electronics
Document_id: 54219
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: How to the disks copy protected.

In article <rcstage1.132.735807672@urc.tue.nl> rcstage1@urc.tue.nl (Guido Klemans) writes:

[stuff about hardware keys]

>If you put another computer on the port instead of the key, you can hack 
>them by reading what happens. So I've been told, I've never seen this done 
>but I think it's possible. You'd need some hardware knowledge and some 
>software to read the port!

True, which is why many of the newer keys ship out, oh, maybe 32 bits or
so, have the key encrypt them, and return them to the PC.  Making a bunch
of these 32 bits part of your program code is a good way to make sure
things won't run without the key. :-)  Anyway, then, this scheme at least
defeats your approach.  It's a little costly, though.

Personally, I don't believe in copy protection, and agree with the thought
that the mass inconvenience that it causes all legal users far outweighs
the gains from what few pirates won't be able to copy the program.

					---Joel Kolstad


Newsgroup: sci.electronics
Document_id: 54220
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: help with phone wire: which ones are "tip" & "ring"?

In article <1993Apr22.103922.23177@husc3.harvard.edu> mlevin@husc8.harvard.edu (Michael Levin) writes:
>
>I just bought a little gizmo that is supposed to be installed "in
>series with the tip or ring lines" of the phone wire. Which ones are
>those? Suppose I am holding a regular phone wire, such that the little
>plastic tooth (on the little plastic square thing with the naked lead
>ends that you plug into the phone) is facing down, and away from me.
>Which of the 4 wires that I see is the "tip" and which is the "ring"?
>Please reply to mlevin@husc8.harvard.edu.
>
>Mike Levin
>
Mike, Ring is the RED wire. Tip is the GREEN wire of most standard
phone lines. They two constitute the two wires most often used for
voice telephone (the two live lines). They are the two innermost
connectors of an RJ-11 phone jack.

Another way of telling is that if you measure voltage from RED to
GREEN (ring to tip. tip/green being at ground potential of the
voltmeter), it should read -48 volts in the on-hook no-ring position).
I am 98% sure it's -48 V and not +48 volts. Doesn't hurt a phone too
much if they're reversed, it's just bad if one happens to somehow get
grounded to earth ground elsewhere).

Additionally, when off-hook, the voltage drops to about -4 to -9 Volts
DC. I think it is supposed to correspond to a 36 to 40 mA current
loop. And lastly, when ringing, the two wires develop an AC potential
of about 80 V p-p at 20 to 30 Hz across them (where you get the
electromechanical old fashioned bell ringer from).

Hope that clears things...
-squish@endor.harvard.edu




Newsgroup: sci.electronics
Document_id: 54221
From: squish@endor.uucp (Shishin Yamada)
Subject: Re: blinking LEDs?

In article <199304241801.AA26885@kepler.unh.edu> dmn@kepler.unh.edu (There's a seeker born every minute.) writes:
>
>
>   Where can I buy blinking LEDs besides radio shack? 
>
>
>  * Does anyone sell blinking LEDs with variable flash rate? (by voltage
>    I guess) If so, what hertz (pulse) rate are they adjustable or set to?
>
>     I'd like blinking LEDs that can be set for approx 5 hz, 10 hz, 
>     15 hz, or 20 hz. Something like that... I'm interested in what's
>     out there for flash rates. I like the idea of LEDs with flasher 
>     circuits already in them. I hate soldering ICs in general. Guess I
>     don't have a hell of a lot of patience. 
>
>
>      Thanks,
>
>         Dana
>
If you want slow LED flash rates, adjustable by switches (or by a
4066/4016 digitally controlled switch), I suggest looking at a 555
oscillator chip. They cost ~$1 at Radio Shack (much cheaper in
quantity at quality places), and you will be able to find good info
about simple circuits in a 555 oscialltor notebook (I think Forest
Mims has one at Radio Shack). You'll have to toy with
resistor/capacitor values OR you can use your head with a little math
to get the right frequencies. Any engineer worth his salt, can make a
555 osciallator... It's in the book, and left up to you to see (I hate
doing ASCII circuit graphics). The 555 can accurately go from a few Hz
to about 500 KHz (I think).

About the Tape Recorder gizmo, you could alter a stereo tape deck to
use one channel as a DATA line (for flashing LED), and one as audio
line (for voice or music). This would eliminate a lot of noise.

The data line is probably most easily done
by some kind of PLL or bandpass filter (using just an op-amp). The 565
chip is a good PLL, and not hard to work with. However if you nothing
about how a PLL works, I suggest you don't try this. Op-Amp
information can also be found in the Forest Mims Radio Shack
info-booklets, and the popular 741 op-amp is a snap to work with.
Setting frequency and bandpass filter values are not so easy, so I
would suggest the 555 method firstmost... I have no idea what this is
going into, so I am really generalizing...

As for manufacturing techniques, if you're only goofing with it, I
suggest you breadboard the thing... No need to solder. Wire-wrap would
be the next, more permanent step. And lastly, soldering/PCB making.
Hope that clears things......

-squish@endor.harvard.edu


Newsgroup: sci.electronics
Document_id: 54222
Subject: Re: what to do with old 256k SIMMs?
From: cvafymfa@vmsb.is.csupomona.edu (Srikanth Viswanathan)

In article <1qkf2hINN65c@rave.larc.nasa.gov>, kludge@grissom.larc.nasa.gov (Scott Dorsey) writes...
>In article <C5JCH1.FrC@ulowell.ulowell.edu> wex@cs.ulowell.edu writes:
>>In article <1993Apr15.100452.16793@csx.cciw.ca>, u009@csx.cciw.ca (G. Stewart Beal) writes:
>>|> >	I was wondering if people had any good uses for old
>>|> >256k SIMMs.  I have a bunch of them for the Apple Mac
>>|> >and I know lots of other people do to.  I have tried to
>>|> >sell them but have gotten NO interest.
>>

Well,  if you're willing to spend a little money,  you could buy one
of those IDE caching controllers (assuming you have an IDE of course)
and put the 256K SIMMs on them.  Hardware cache!

Srikanth

Newsgroup: sci.electronics
Document_id: 54223
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: Lead ACid Batteries Part 2!!!

In article <1993Apr25.013013.13717@cronkite.ocis.temple.edu>, camter28@astro.ocis.temple.edu (Carter Ames) writes:
> 
>    I thought the first thread was hilarious, so here goes another post.
> 
> Some more background information on what has happened to my poor batteries.
> 
>   One year, I left the batteries in the garage.  The garage is Unheated.  
> They were left in their places that they needed to be.  One in the riding
> lawnmower (what a lux) and one in each motorcycle.  The battery in the 
> riding lawnmower was about 3-4 years old, and one of the cycle batteries 
> was new, and one was around 5 years old.  Upon spring time, I discovered
> that all of the batteries were dead, and needed to be recharged.  They all
> worked properly, except for the older ones, and they had to be replaced 
> about halfway through the summer.  (they had originally been stored
> in the garage, and I think I remember my dad charging them in spring)
>   Last year, I decided to bring them in to the basement, which has two parts.
> one is dirt and brick, and the other is concrete.  I brought in all three, and
> discovered in the spring, (about 15 days ago) that not only were the batteries
> dead, but when I put the charger on them, the charger said "HMMMMMMMM" and 
> the amp-meter read around 1,000,000,000  (In other words, it was pinned)
> the internal circut tripped, and I went on to the other batteries.  They
> were the same.  
>    Realizing that we still had 2 GIGANTIC sailboat batteries, also lead
> acid, I decided to put the charger on them.  (these had been sitting for around 1 and a half years, on the brick and dirt part) and noticed that they only
> needed a small charge, around 2 hours or so on trickle.  I tested them
> by using them at the local gas station for giving jump starts, and they
> worked fine for around 25 of 'em. 
>   This leads me to believe one of several things.
>      1) I bought really #$%tty batteries last year. (sorta true)
>      2) the concrete has something to do with the discharge of the
>         batteries.
>      3) There was enough moisture to short out the terminals in the 
>           room where the concrete is, 
>      4) The dirt room was able to absorb the moisture in the air
>          better than concrete.
> 
> (BTW, I can almost waterski in the dirt room)  
> 
>    Any other ideas?
>     *could be the aliens, anything is possible.*
>  
 
The lead-acid secondary cell releases energy (electricity) with the following
chemical reaction:
 
Pb + PbO2 + 2H2SO4 --> 2PbSO4 + 2H20
 
Lead and Lead (IV) Oxide and Sulfuric Acid produce Lead Sulfate and Water
 
The standard heats of formation at 25 C (77 F) of the various compounds are:
 
              Heat of formation
Compound      at 25 C, kcal/mole
--------      ------------------
   Pb               0.00
  PbO2            -65.0
 H2SO4           -193.69
 PbSO4           -218.5
  H20             -68.3174
 
The heat of reaction at 25 C is therefore -60.6 kcal per mole PbSO4 produced.
Note that lead sulfate is not very soluble (0.0048 grams per 100 grams water
at 25 C), and it will thus precipitate out of solution where the reaction is
occurring, or the cathode (positive terminal) of the battery.  (I am almost
sure it is the positive terminal where the precipitate forms, but I may be
wrong.  Oh well, I don't have a corroded battery to corrobate, and I don't feel
like thinking through it right now.)
 
What is important to notice here is that the reaction, as you knew it would be,
is exothermic, or energy discharging.  If moisture with dissolved electrolytes
(acid rain) condenses on the battery, a conductive path between the terminals
may form.  This will discharge the battery as the chemical reaction proceeds.
The reaction is reversible, if electricity (from an alternator or battery
charger) is put back into the battery.
 
Lead-acid batteries must change in chemical composition to discharge.  Each
cell has all the reactants necessary for the reaction.  The non-reacting posts
(terminals) of the lead-acid battery are there to remove (or add) electric
energy during a discharge (or charge).  Because the reaction is exothermic, it
has a tendency to happen, though quite slowly under normal circumstances.  So
while keeping the battery dry is a good idea, it is not a total solution.
 
To understand why lead-acid batteries DO INDEED discharge faster when stored on
concrete as opposed to wood or earth (dirt), one should recall LeChatelier's
Principle, which can be paraphrased as:  anything subjected to some stress will
act to move to a more comfortable position.  Here are the thermal conductivities
of a some selected materials:
 
                                              thermal conductivity
       material           Temperature, C (F)  BTU/(hr-ft-ft)(F/ft)
       --------           ------------------  --------------------
diatomaceous earth,            204                   0.051
 natural, across strata        871                   0.077
diatomaceous, natural,         204                   0.081
 parallel to strata            871                   0.106
diatomaceous earth powder     (100)                  0.039
  (density, 18 lb/cu.ft)      (200)                  0.042
                              (300)                  0.044
                              (400)                  0.048
                              (500)                  0.051
concrete (cinder)              ---                   0.20
         (stone)               ---                   0.54
         (1:4 dry)             ---                   0.44
pine (across grain)             15                   0.087
   (parallel to grain)          21                   0.20
oak (across grain)              15                   0.12
maple (across grain)            50                   0.11
 
Note that the thermal conductivity for "dirt" (diatomaceous earth) goes down
with temperature.  Also, 204 C is about 400 K, and the values for earth powder
are on the same order of magnitude as natural earth.  The thermal conductivity
of concrete is around a factor of 10 greater than that of dirt, and is 2-4
times greater than wood.
 
It is these differences in thermal conductivity that cause the battery on
concrete to discharge faster than that on dirt or wood.  At any instant the
discharge reaction is occurring, energy is being released, either as electricity
or heat.  (Thermal conductivity of air is about 0.015 BTU/(hr-ft-ft)(F/ft).)
During storage, except for the trickle that passes through any condensate on
the battery, this energy is mostly released as heat.  The higher conductivity
surface will remove the heat proportionately faster than the lower conductivity
surface.  Thus, if you perfectly insulated a dry battery on all but the bottom
surface, at any given battery temperature above the storage surface temperature,
the battery on a concrete surface will be discharging about 10 times faster
than that on dirt.
 
This is where LeChatelier's principle comes into play.  Removing energy from
the exothermic reaction will drive the reaction further to completion.  If the
reaction normally occurs at room temperature, keeping the battery at that
temperature requires the removal of any heat produced.  A concrete surface is
a better heat sink than a dirt or wood surface.  Store a battery in the corner
of a poured concrete basement, and you have 3 surfaces removing energy, which
"pulls" the reaction along.
 
Also, if water evaporates from the battery, that elevates the ratio of sulfuric
acid to water.  This will tend to drive the discharge reaction.
 
Jeff White      jhwhit01@ulkyvx.louisville.edu
 
"How do I get the ketchup out of my pocket protector?"  French fries!

Newsgroup: sci.electronics
Document_id: 54224
From: wd@cs.tu-berlin.de (Wolfgang Diestelkamp)
Subject: Re: How universal are phones these days?

In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

> I'm wondering if I can tote my American touch tone phone around with me
> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
> for that in Europe.  The question is if the general electronics work
> the same.  I can buy a different wall plug and refit it (I'm sure I'd
> have to), but would that do the trick?

Two things to watch for:
In Germany (and I think the same holds for Sweden) only some
of the connections can handle tone dialing, so make sure the
phone can be set to pulse dialing.
In Sweden, the '0' is the first digit and all other digits
are pushed "down" by one position; this makes dialing (and
in the process converting numbers) an interesting task.
Otherwise, it is technically no problem to connect a foreign
phone to either the German or Swedish phone system.
OTOH neither you nor I would ever try that, as it is of course
illegal.
-- 
Wolfgang Diestelkamp
wd@cs.tu-berlin.de
wolfgang@first.gmd.de


Newsgroup: sci.electronics
Document_id: 54225
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: 600RPM Floopy drives - UPDATE!

In article <C5wIEE.Gn3@ms.uky.edu> msunde01@mik.uky.edu writes:

>> Hopefully this should sort it all out .... not bad for 9 quid (normally
>                                                         ^^^^^^
>Pardon my ignorance of foreign currency and exchange rates, but what is a  
>quid, how does it relate to the British Pound (or whatever it's called)  
>and what is that in American Dollars??? :-)
k
Sorry ... should have used correct terminology

1 Quid = 1 Knicker = 1.54 approx U.S. Dollars 

The Terry Pratchett Book "Good Omens" contains an adequate explanation
of the rather strange UK money system, past and present for "Americans, 
Tibetans, and other alien species" :-)

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================


Newsgroup: sci.electronics
Document_id: 54226
From: lhe@sics.se (Lars-Henrik Eriksson)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:
   In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

   > I'm wondering if I can tote my American touch tone phone around with me
   > to Sweden and Germany.  It's DC powered, and I can buy a special adapter
   > for that in Europe.  The question is if the general electronics work
   > the same.  I can buy a different wall plug and refit it (I'm sure I'd
   > have to), but would that do the trick?

   Two things to watch for:
   In Germany (and I think the same holds for Sweden) only some
   of the connections can handle tone dialing, so make sure the
   phone can be set to pulse dialing.

Most (if not virtually all) swedish exchanges can handle tone
dialling. Many older electromechanical exchanges have been modified
accept tone dialling.
--
Lars-Henrik Eriksson                            Internet: lhe@sics.se
Swedish Institute of Computer Science           Phone (intn'l): +46 8 752 15 09
Box 1263                                        Telefon (nat'l): 08 - 752 15 09
S-164 28  KISTA, SWEDEN                         Fax: +46 8 751 72 30

Newsgroup: sci.electronics
Document_id: 54227
From: red@tina.dei.unipd.it (Piergiorgio Sartor 274199/IL)
Subject: PALs, GALs

Does anyone know how can I get detailed information about PALs and GALs.
Please reply via e-mail.
Thanks a lot in advance.
-- 
					red@paola.dei.unipd.it
					red@maya.dei.unipd.it

Newsgroup: sci.electronics
Document_id: 54228
From: tde9106@hgs.se (Joakim Gunnarsson)
Subject: Re: How universal are phones these days?

wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:

>In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

>> I'm wondering if I can tote my American touch tone phone around with me
>> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
>> for that in Europe.  The question is if the general electronics work
>> the same.  I can buy a different wall plug and refit it (I'm sure I'd
>> have to), but would that do the trick?

>Two things to watch for:
>In Germany (and I think the same holds for Sweden) only some
>of the connections can handle tone dialing, so make sure the
>phone can be set to pulse dialing.
>In Sweden, the '0' is the first digit and all other digits
>are pushed "down" by one position; this makes dialing (and
>in the process converting numbers) an interesting task.

This is just basicly right. The connections that cannot handle touchtone dialing is very few. I would estimate a couple of percents and if you are in a bigger
town, there is none that cannot handle tone dialing.
And regarding our swedish dialing system (a rather screwd up system), that does
just apply to pulsdialing. Not to touchtone.
Btw; Norway is even more interesting. They got both system! So you need different phones depending on where in the country you live.

/Joakim Gunnarsson - tde9106@abacus.hgs.se


Newsgroup: sci.electronics
Document_id: 54229
From: blumenow@underdog.ee.wits.ac.za (Warren Blumenow)
Subject: RF Communications Link

Hi.

Our problem is the following:

We have to design an RF link for a distance of 250 m.  We're using
standard RS232 waves (square pulses) as the modulating waves and the 
carrier wave is sinusoidal.  The link has to be bidirectional.
 
We would appreciate any advice on the type of modulating techniques
or antennas that we should use.

Please internet email us at:  007gjf3@witsvma.wits.ac.za  (Nando)
                         or   007bww3@witsvma.wits.ac.za  (Warren)
                         or   blumenow@underdog.ee.wits.ac.za  (Warren)

Thank you very much in advance.

N & W

Newsgroup: sci.electronics
Document_id: 54230
From: cyberman@toz.buffalo.ny.us (Cyberman)
Subject: Re: Blue LED's

{Gladman Aviv} said
   "Re: Blue LED's"
      to <All> on 04-24-93  01:51

 GA> In order to emit blue light, a semiconductor must have a band gap
 GA> energy within the region of 2.6 to 2.8 electron Volts. According to my
 GA> physical electronics prof, you can't get an LED with that band gap.
 GA> That's why you don't find blue LEDs or, for that matter, some other
 GA> colour of LEDs. That is not to say that blue LEDs can't be found.  I've
 GA> seen 'blue' LEDs sold, but they were just your typical visible light
 GA> LED in a blue plastic covering. They didn't emit very much light...

    This is not true they have and do make blue LED's they are
    about 2.80 in digikey. 470nm wavelength by the way

                Stephen Cyberman@Toz.Buffalo.NY.US
             Mangled on Sun  04-25-1993  at 13:33:46

... "I think 640K will be enough.." -Bill Gates 1981
___ Blue Wave/QWK v2.12
  

Newsgroup: sci.electronics
Document_id: 54231
From: abjoern@idt.unit.no (Anders Bjoernestad)
Subject: Re: How universal are phones these days?

In article <1rgka2$n4k@corax.udac.uu.se>, tde9106@hgs.se (Joakim Gunnarsson) writes:
|> 
|> >Two things to watch for:
|> >In Germany (and I think the same holds for Sweden) only some
|> >of the connections can handle tone dialing, so make sure the
|> >phone can be set to pulse dialing.
|> >In Sweden, the '0' is the first digit and all other digits
|> >are pushed "down" by one position; this makes dialing (and
|> >in the process converting numbers) an interesting task.
|> 

I think all connections in Norway can handle touchtone dialing.

|> Not to touchtone.
|> Btw; Norway is even more interesting. They got both system! So you need different phones depending on where in the country you live.
|> 
The Oslo-region has one system, the rest of the country another system.

|> So you need different phones depending on where in the country you
|> live.
(Almost right for pulsdialing.)
Some phones have a little switch inside, so you are able to use them
all over Norway, or you can just renumber the numbers on your phone.



-- 
Anders Bj{\o}rnestad
Division of Computer Science and Telematics
Norwegian Inst. of Technology, Trondheim, Norway
Email : abjoern@idt.unit.no    (Internet)
X.400 : C=no; PRMD=uninett; O=unit; OU=idt; S=abjoern  

Newsgroup: sci.electronics
Document_id: 54232
From: mje@sni.co.uk (Mike Evis)
Subject: Caltech PUFF PD ftp? RF Tools?

Hi there,

Does anyone know whether the PUFF RF design package is available
via ftp from any site? As I understand it, it is in the public
domain - please correct me if I'm wrong on this one.

Any other PD RF design tools out there that can be recommended?
Especially microstrip filter tools...

73's
Lehane

--
Lehane Kellett. G8KMH. Siemens Nixdorf Information Systems, Bracknell.
lehane@sni.co.uk Phone 0344 850393  Fax 0344 850401 Compuserve 100065,3563 
Standard disclaimers apply. Warranty void if opened.                    

Newsgroup: sci.electronics
Document_id: 54233
From: mike@netnews.louisville.edu (Mike Harpe)
Subject: Re: How to drive an array of LEDs?

ptorre@hardy.u.washington.edu (Phil Torre) writes:

>I have a project in mind that requires an array of LEDs that can be addressed
>individually by a microprocessor (say, 16x16 or so).  Is there an LSI that
>is designed to drive an LED array (including RAM to hold the array state),
>or failing that, some way of multiplexing the display so I don't have to
>latch a bit for each LED using a discrete latch?  (I want to avoid having
>a huge board covered with 373s if possible!)  Thanks in advance...

Maxim makes a chip that does exactly what you want. The MAX7219 drives 8
7 segment LED displays with full decode or drives 64 discrete LED's with
a 3 wire serial interface.  The chips can also be cascaded to allow very
large arrays.  I am working on a sign display using this part.

I'll have to post the contact info for Maxim later, it's at home.  There was
a series of articles on this chip in the last couple of Circuit Cellar Ink's.

Mike Harpe
-- 
Michael Harpe, Programmer/Analyst      Information Technology, Ormsby Bldg.
mike@hermes.louisville.edu             University of Louisville
(502)588-5542                          Louisville, Ky. 40292
"He's not a man, he's a remorseless eating machine!" - The Simpsons

Newsgroup: sci.electronics
Document_id: 54234
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: How to the disks copy protected.

Comments about "who needs backup copies"?  and "YOU do" deleted....

I'll toss in my 2 cents worth - I've begun to think that distribution
disks are made on some of the least reliable floppy disk stocks available.
We've been especially plagued by Borland's distribution disks.  I'm 
lucky if I can install from them as many as 3 times before they crap 
out on me.  So definitely, as a matter of course we ALWAYS make copies
to do our installations with.

--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
Document_id: 54235
Subject: Re: How to the disks copy protected.
From: sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen)

Kuo-Sheng (Kasey) Chang (kschang@sfsuvax1.sfsu.edu) wrote:
> In article <1993Apr23.102935.17390@miavx1.acs.muohio.edu>
> sjmadsen@nextsrv.cas.muohio.edu (Steve Madsen) writes: 

> > This is not a good idea.. I upgraded my motherboard last fall.  I >would
> have been quite pissed at any software that would have forced me to
> >reinstall simply because I changed motherboards. >

> Opinion is understandable.  :-)  I assume you have a tape drive?  Not all
> of us have about 200 floppies around for backup, you know.  

	Actually, no I don't have a tape drive.  In the event of a total
hard disk failure, I reinstall the apps from originals, and restore the data
from the backups I keep of that.  With upwards of 100Mb of stuff on my hard
disk, there is no way I'm going to try and back it all up without a tape
drive. :)  Would be nice to have one though!

> RAM is something you add all the time, so no.  It's more like BIOS
> manufacturer and/or processor type (386/486/etc).  Data cannot be used,
> esp with these new Flash ROM BIOS machines with updates on a diskette.

	Maybe, maybe not.  Today it doesn't happen as often (I would hope),
but then if a BIOS is buggy and the user gets an upgrade, the BIOS
information is going to change, at least the date anyway.  Tagging the BIOS
manufacturer is still going to falsely tag those users who upgrade the
motherboard.  This type of upgrade doesn't require a hard disk
backup/restore.

> On the other hand, to make this LESS intrusive it could be disguised as
> "Please Insert Original Disk #XX as I need file YYYYYY for update".  :-) 
> It would be perfectly reasonable...  Sort of.

	As long as it wasn't done too terribly often.  Otherwise I think it
would get annoying and the user would go looking for other software.

> > > This is silly.  It's much easier to loan disks to a friend and let
> >them do an install than to backup your copy already on disk, and then
> give >them that.  Your scheme isn't going to stop anyone. 

> Of course it is easier.  Are you saying then the originals SHOULD allow
> only one install?  What is your point?

	Of course not.  If something gets corrupted and my app needs to be
reinstalled, the *worst* thing I want that software telling me is "this
software has already been registered to <blank> and it is against the law to
install it on other machines."  Or something similar; Access for Windows
does this and it only requires a click on "OK" to go away.  Pretty
non-intrusive, but it gets the point across.

> What I said was the program should have certain restriction (such as the
> restrict-to-one-machine) UNTIL the program is registered with the
> manufacturer.  The manufacturer will then supply the
> then-proven-legitimate-user with a patch that will disable the restriction
> and PROUDLY PROCLAIM the legal copy with the "Registered to XXX" screen.

	This is a great idea.  I like the key system that some shareware
products use.  The only problem is that it will be difficult for big
software companies to implement this without it getting very
cost-ineffective for them and more of a burden than a benefit to the users.

--
Steve Madsen
sjmadsen@nextsrv.cas.muohio.edu

Ask me about Linux, the free 386 unix!

Newsgroup: sci.electronics
Document_id: 54236
From: mbattist@magnus.acs.ohio-state.edu (Mark A Battisti)
Subject: Clear LCD or LED "sheets"

I am interested in finding a supplier for an array of leds on material which is
transparent when nothing is lit.

I'm not quite sure what LCD screens are like away from the laptop but I would 
guess they are not too clear.

An ideal item would be an LED array for which each LED is about 1/2" square.  
(Yes very course)  This is for distance viewing, but on a window.

Any pointers of suggestions would be much appreciated.

-Mark Battisti
mbattist@magnus.acs.ohio-state.edu

1940 Summit Street #B
Columbus, Ohio 43201
(614) 299-0317

Newsgroup: sci.electronics
Document_id: 54237
From: mcarr@austin.onu.edu (Michael Carr (x1723))
Subject: Digital->AC Scaling


	Being in the "visualization" stage of a circuit design right now,
I was wondering what the best way to "scale" an AC voltage using an 8-bit
digital word is. I am thinking of using the common method of sending the
word through an ADC and then comparing it with the AC voltage (converted
to a sawtooth wave) to get a duty cycle. However, I am leary of this
method because it a) requires a lot of parts, and, more importantly, b)
creates a lot of interference from the switching on the entire AC line. I
realize that correct filtering could cancel out most of this interference,
but that would require more parts and boost the price further.
	Someone mentioned to me that they had seen an IC which input 8
bits of data and DIRECTLY scaled the AC voltage coming in all on-chip.
Unfortunately, he couldn't remember the chip number or the manufacturer;
if anyone else has heard of this chip, please e-mail me.
	I am building this project as a "dimmer box" for a light
controller circuit and it is important that the cost of each box remains
very low because one dimmer is required for each light that the user
wishes to control (well, each channel, at least). Therefor, if each box
costs $150, I doubt that an end user will want to dish out ($150 x 16 =
$2400) for sixteen channels... This is something I have noticed about
today's dimmer boxes; they are so expensive!
	Anyway, any help which someone could offer on either a method of
easily doing this or info about the chip which will do it for me (always
the preferred method... :) will be greatly appreciated!

	Michael Carr
	m-carr@onu.edu


Newsgroup: sci.electronics
Document_id: 54238
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: RF Communications Link

In article <blumenow.7@underdog.ee.wits.ac.za> blumenow@underdog.ee.wits.ac.za (Warren Blumenow) writes:
>We have to design an RF link for a distance of 250 m.  We're using
>standard RS232 waves (square pulses) as the modulating waves and the 
>carrier wave is sinusoidal.  The link has to be bidirectional.
>We would appreciate any advice on the type of modulating techniques
>or antennas that we should use.

What frequency is your carrier?

Have you considered using two tones, one for 1 and another for 0?

How high is your RS-232 data rate?

Can you use more than one carrier freq?

Have you considered hiring an RF data transmission consultant?

Just Curious,
Galen Watts, KF0YJ


Newsgroup: sci.electronics
Document_id: 54239
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: Power, signal surges in home...

In article <1993Apr26.045628.5617@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>brian@ucsd.edu (Brian Kantor) writes:
>
>: Listen to the interference.  If you hear voices clearly, it almost
>: certainly ISN'T ham radio, and might well be CB.  If you can record a
>: bit of it, you could take the tape over to a local ham operator's house
>: and ask him for his opinion of what you're hearing.  Most communities
>
>You cannot do that legally. 

Why can't he record it legally?  It may not be admissable in court, but
recording for personal use is legal.  If he wants to play it for his ham
friend, that's legal too, as long as he doesn't charge admission.

>Unfortunately, most consumer equipment is succeptable - it is all poorly
>designed.

Here, Here!
>
>: (BTW: hams are ALLOWED amplifiers; CB isn't.  "illegal ham amplifier"
>: doesn't compute.)
>
>It does, but not for a mobile radio. There are very few mobile rigs that
>could power a 1500 watt amplifier.
>Bill

It doesn't actually have to be 1500 watts at 100 feet.  I've heard radio
transmissions from concert security over guitar amps with no guitar plugged
in, and security uses radios transmitting 2-5 watts into a rubber duck antenna,
which acts more like a dummy load than an antenna.

Hey Bill, where were you three weeks ago when all this stuff was posted
and dealt with?

Galen Watts, KF0YJ


Newsgroup: sci.electronics
Document_id: 54240
From: kpjone01@ulkyvx.louisville.edu
Subject: What type of IC is this???

Greets,
 
I have an IC I need help in identifying.  It is an 8-pin IC with the following
label:  W03563  9144w4  
 
ANY help would be greatly appreciated in identifying this chip.  
 
Kevin


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kevin Jones                                   KPJONE01@ULKYVX.CT.LOUISVILLE.EDU
Lab Supervisor                                KPJONE01@ULKYVX.LOUISVILLE.EDU
Computing and Telecommunications              PHONE:  502-588-6303
University of Louisville, KY                  FAX:    502-588-0150

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                 The only good racist is a dead racist.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Newsgroup: sci.electronics
Document_id: 54241
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: HELP!  Looking for Oscilloscope source

Hi all,

I am looking for a new oscilloscope (BK 1541-B, it looks like, Goldstar OS904S
if I can find one cheap enough) and would like suggestions on a low-priced
source for them.

(Currently, BTW, Fry's electronics in Los Angeles has the 1541-B for $598,
 the best price I've seen overall for now - They carry the GS OS902S for 
 $490, but I need the 904S because of the 40 MHz B/W)

Thanks all.
-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
Document_id: 54242
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: Clear LCD or LED "sheets"

mbattist@magnus.acs.ohio-state.edu (Mark A Battisti) writes:

>I am interested in finding a supplier for an array of leds on material which is
>transparent when nothing is lit.

>I'm not quite sure what LCD screens are like away from the laptop but I would 
>guess they are not too clear.

>An ideal item would be an LED array for which each LED is about 1/2" square.  
>(Yes very course)  This is for distance viewing, but on a window.

>Any pointers of suggestions would be much appreciated.

What, pray tell, are you putting together?  And what about costs?  And does it
have to be transparent as in totally transparent?  Or just transparent enough
to allow light from the other side to shine through?

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
Document_id: 54243
From: long@spk.hp.com (Jerry Long)
Subject: Re: 2% silver solder

Andy Shiekh (shiekh@ictp.trieste.it) wrote:
:   I have seen the existance of electronics solder with a 2% silver
: content that seems to have good wetting and fatique reatings.
:   Can anyone tell me why it is not used? (silver is not such an expensive
: metal).
: 
: 
: Andy
: 

For the most part, silver-solder is not used for general soldering
tasks due to the mechanism of dendritic growth. Silver-solder, when
exposed to high humidity and placed in an electric field, will actually
grow dendrites which are conductive and will adventually electrically
short across closely spaced nodes which are creating the field. For this 
reason, silver is allowed only in hermetically sealed assemblies.
Fortunatly, tin-lead solder is quite stable and will not grow dendrites
as fast as silver-solder. Therefore, it is used extensively.

 
Jerry Long

long@spk.hp.com
****************************************
Disclaimer.... Opinions are my own and
do NOT reflect those of my employer.  
**************************************** 

Newsgroup: sci.electronics
Document_id: 54244
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Laser vs Bubblejet?

There is a cartridge capping upgrade for older deskjet printers
available from hewlett-packard.  Older original deskjet and
possibly deskjet 500 units may have a black plastic slide with
rubber capping components in the cartrige parking area on the right
side (viewed from front) of the printer.  Newer printers have a
gray or white plastic slide.  The black plastic slide can allow
your cartridge to dry out.  There was and may still be information
packaged with ink cartridges explaining the situation.  HP placed a
coupon for a free upgrade kit to modernize old deskjets to the new
capping mechanism.  I did this on my printer and did indeed find
that the cartidges now last longer.

I don't have the information handy.  I suggest contacting your
nearest HP service center for information on obtaining the kit.

HP has upgrade kits that consist of electronics and mechanical
components that vary depending on the starting level printer and
the level to which you wish to upgrade.  I upgraded my original
desket to a dekjet 500.  The kit was fairly expensive.  You are
likely better off selling your old printer and purchasing a new
deskjet 500 now that prices have declined so much.  Upgrading an
original deskjet to 500 requires a fair amount of skill, but no
soldering.  Upgrading a deskjet plus to a 500 is involves swapping
the processor card and changing a few minor parts.  Contact your HP
service center for further information.

The PCL language used by Deskjets is considerably different from
the PCL used by laser printers, especially the newer laser
printers.  The biggest problem is dumb laser drivers that send a
raster end command after each scan line.  This makes no material
difference for lasers, but causes the deskjet to print the
accumulated raster.  As you might guess, the result is hideously
slow printing.  The new DOS Wordperfect print deskjet drivers are
still guilty of this particular behavior.  From the way Wordperfect
works, this would not be easy to change.  Windows Wordperfect works
efficiently unless you use the DOS drivers instead of Windows'.

The PCL4 dialect used in the Laserjet IIIP allows compression that
permits a full page 300 dpi image to be rendered with only one
megabyte of memory.  An uncompressed image could be as large as
about 909 Kbytes, but the printer needs about 300K of memory for
its internal house-keeping.  Laserjet IV models support banded
printing that allows incrmental download of the image with
compression in limited memory situations.  Deskjet downloadable
fonts are not compatible with laserjet fonts.

A single page from a laserjet only requires about 20 seconds.  This
is faster than any but the most trivial printing from a deskjet
printer.  The presumption, of course, being that the laser printer
has completed its warm-up cyle.

Until ink chemistry is changed, wicking resulting in image
deterioration is unavoidable.  I won't use the word impossible, but
matching laser quality output from a deskjet printer is unlikely.
Chosing an appropriate paper type helps, but does not eliminate the
problem.

Laser printers are more wastful of energy and consumable
components.  HP does accept return of spent toner cartridges,
mitigating the material waste problem to a degree.  Energy waste
could use more work.  Warm-up times have decreased, allowing
stand-by current consumption to be significantly reduced in the
laserjet IV.

Kyocera produces a laser print engine that employs an amorphous
silicon imaging drum with a replacable toner system.  The image
drum is good for approximately 100K copies.  It is a very nice
print engine.  I wish HP used the Kyocera engine.  Kyocera also has
a neat modular paper source and stacker system.

The recommended duty cycle for a deskjet is significantly lower
than any of HP's laser printers.  The pick-up pressure rollers are
subject to wear and I case confirm eventually do wear out.  The
usual symptom is that the printer becomes reluctant to feed paper.
The paper feed is integrated in a transport mechanism that is a
single part from HP service.  Replacement cost for the transport is
almost $200.  The feed rollers are not separately replacable,
though it would not be a difficult job for a competent technician.
I have disassembled and reassembled the transport on my own printer.

It depends upon the application which printer is best for you.  If
you only print 5 or 10 pages a day and are satisfied with the
appearance of output, the deskjet is a very good choice.  As noted,
the deskjet 500 is my choice for personal use.


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 54245
From: cfb@fc.hp.com (Charlie Brett)
Subject: Re: Blue LED's

Baden de Bari (baden@inqmind.bison.mb.ca) wrote:
:  
:         So what's the story here... we're all stuck with the regular
: green, red, and off yellow-orange LED's!?  What gives!!??
:         Anybody have a 'scoop' on FAIRLY LOW PRICED >BLUE< LED's???

If your looking for LEDs in the $.10-$.20 range, forget it. Blue LEDs just
recently became available and the materials they are made of are expensive.
Maybe in the future they will become less expensive (and brighter), but
for now it's going to cost you and the output will be limited. If they ever
do get as efficient and cost effective as red and green LEDs, you're probably
going to see a whole new family of color displays.

         Charlie Brett - Ft. Collins, CO

Newsgroup: sci.electronics
Document_id: 54246
From: bomr@erich.triumf.ca (Rod Nussbaumer)
Subject: Re: multiple inputs for PC

In article <93114.142835U19250@uicvm.uic.edu>, <U19250@uicvm.uic.edu> writes...
>Can anyone offer a suggestion on a problem I am having?
>I have several boards whose sole purpose is to decode DTMF tones and send
>the resultant in ASCII to a PC.  These boards run on the serial interface.
>I need to run * of the boards somwehat simultaneously.  I need to be able to ho
>ok them up to a PC>  The problem is, how do I hook up 8+ serial devices to one
>PC inexpensivley, so that all can send data simulataneously (or close to it)?
>Any help would be greatly appreciated!
>Abhin Singla
If you can modify the design of the DTMF decoder, the ideal comunications
would be over a multi-drop system, like RS-485.  RS-485 boards are available
for PC's, probably cheaper than a bunch of RS-232 channels, and RS-485 is
cheaper to build onto your satellite modules, using only a single supply
8-pin DIP driver chip.  Software at the PC end would be similarly complex
for either RS-232 or RS-485, in my opinion.  The higher data rates possible
with RS-485 would permit quasi-simultaneous data transmission.
Hope this helps.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Rod Nussbaumer, Programmer/Technologist       Bitnet: BOMR@TRIUMFER
  TRIUMF --- University of British Columbia,  Internet: bomr@erich.triumf.ca
  Vancouver, BC, Canada.                         Phone: (604)222-1047 ext 510
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Newsgroup: sci.electronics
Document_id: 54247
From: kniha@carson.u.washington.edu (Dagmar Amtmann)
Subject: Re: How universal are phones these days?

I don't know much about phones in Germany, but this is what I know: I bought
a phone in the U.S. for my mother who lives in Bratislava, Slovakia and it
works just fine. The problem is they don't have wall jacks like we do here.
There is a wire without any jack at the end sticking out of the wall. So you
need to connect the wires (I'm not sure if they have wall jacks in Western
Europe - they may). Hope this helps. Dagmar kniha@carson.u.washington.edu


Newsgroup: sci.electronics
Document_id: 54248
From: gornish@sp1.csrd.uiuc.edu (Edward H. Gornish)
Subject: Radar/Laser Detectors

What are people's opinions about laser detectors?  Escort makes a
laser detector, the Passport 1000, and claims it works fine.  However,
I've talked to some people who have said that it will only work if you
are lucky - i.e. if the cop happens to point his laser at a car in
front of you, and the laser beam happens to reflect back to your
detector.  Otherwise it won't work.  Regular radar, of course, travels
in all directions; hence it is more detectable.  Any comments?

Escort has a deal (till the end of April, I think), where if you buy
their wideband (Passport 3200 - X, K, Ka) and laser detectors, you'll
save $60 off of buying them separately.  In this case, the addition of
the laser detector over the Passport 3200 is only $40 (i.e. Passport
1000 normally costs $100).
--
Eddie Gornish
University of Illinois - Center for Supercomputing Research & Development

gornish@csrd.uiuc.edu

Newsgroup: sci.electronics
Document_id: 54249
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: How do you build neural networks?

In article <1rbs1e$m6s@insti.physics.sunysb.edu> mmoss@ic.sunysb.edu (Matthew D  
Moss) writes:
> 
> Subject says it all, though I should specify that I'm looking for solutions
> that DON'T require me purchasing specific chips, etc....
> 
First you find a congenial member of the opposite sex ...
> 
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu

I couldn't resist :-)

Newsgroup: sci.electronics
Document_id: 54250
From: u009@csx.cciw.ca (G. Stewart Beal)
Subject: Re: Caltech PUFF PD ftp? RF Tools?

In article <1993Apr26.124340.28057@sni.co.uk> mje@sni.co.uk (Mike Evis) writes:
>Hi there,
>
>Does anyone know whether the PUFF RF design package is available
>via ftp from any site? As I understand it, it is in the public
>domain - please correct me if I'm wrong on this one.
>
PUFF is sold by CalTech, although very inexpensively for the quality.
Source was also available for the earlier releases for a nominal charge,
but I'm not sure if this practise is continued.

 
Regards, Stu Beal, VE3MWM, U009@CSX.CCIW.CA,
National Water Research Institute, Burlington, Ontario, Canada.
 
"We'd made it through yet another nuclear winter and
 the lawn had just trapped and eaten its first robin." - Kyle J. Spiller


Newsgroup: sci.electronics
Document_id: 54251
From: arnief@sail.LABS.TEK.COM (Arnie Frisch)
Subject: Re: Luser!

In article <1993Apr23.205906.10745@sol.ctr.columbia.edu> seema@madvlsi.columbia.edu (Seema Varma) writes:
>Hi,
>	I am looking for a high speed 
>D-to-A converter ( at least 8 bits
>and 150MHz) for testing a chip - any
>ideas on where I can find such a monster?
>A paper in the January issue of IEEE Journal
>of Solid-State Circuits (authors from Philips
>Eindhoven) mentions a 1GHz, 8bits, GaAs DAC
>they use in their testing, so I know that 
>such circuits are around somewhere.




TriQuint (Beaverton, Oregon), has been selling an 8 bit, 1 GHz D to A
for several years.  I have used it and it works well, faster settling
time and smaller glitch area than any video d DACs I have seen.  Also,
they have been developing a more precise version that may be for sale
now - it's somewhere in the 10 to 12 bit area at 1 GHz.


Arnold Frisch
Tektronix Laboratories

Newsgroup: sci.electronics
Document_id: 54252
From: ulan@ee.ualberta.ca (Dale Ulan)
Subject: Re: Why circuit boards are green?

kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:

>Not that the question is anything important, but I am still curious:
>Why is that almost all printed circuit boards are green? I have seen
>a few blue ones, but no red, yellow, company logo etc. Is there a
>technical reason or could it be that the marketing "geniuses" have
>not tought about it (yet)?

The green layer is a solder-mask, and is used to make a finished board
look neat, and to avoid solder bridges, especially when using wave
soldering (or any other mechanized approach). I've seen red mask,
but most that I've seen are green.

A bakelite board will look brown in colour, and, if the solder mask
is put on, looks like a brown board with green 'paint' on either side
(or just one side) of the board.
A fibreglass board will look green from the side, because the green
solder-mask makes the board appear that colour. If you got a fibreglass
board with no mask, it would be a whitish-grey colour.
Teflon boards do exist, as well... but I'm not sure about that one.

I'd guess the stuff they invented for solder mask was green, so they're
not about to change. Also, any change in any chemical probably requires
a better than normal cleaning of the machines that make boards. A lot
of companies do not make their own boards... they ship them to a real
boardhouse. 



Newsgroup: sci.electronics
Document_id: 54253
From: kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang)
Subject: Re: How to the disks copy protected.

In article <Apr23.223805.66909@yuma.ACNS.ColoState.EDU>
jmiller@terra.colostate.edu (Jeff Miller) writes: 

>In an earlier article Kasey Chang wrote:

>: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>: via MAIL by mailing in your registration card, THEN the company send you
>: the patch which includes the info you put on the registration card.

>The problem with this scheme, is that when I buy a game, I want to play it
>*THAT* day...mailing a card to and from California would probably take a week
>or more.

I didn't say the program is DISABLED, did I?  (I HATE!!!! it when people
take my words out of context...)  I mean that once you have installed it,
you cannot DEinstall it without registering it, or transfer it to another
machine, or SOME SORT OF LIMITATION (the author will decide), WHICH WILL
BE REMOVED WHEN THE PROGRAM IS REGISTERED.  

--Kasey Chang


Newsgroup: sci.electronics
Document_id: 54254
From: galen@picea.CFNR.ColoState.EDU (Galen Watts)
Subject: Re: What type of IC is this???

In article <1993Apr26.104008.1@ulkyvx.louisville.edu> kpjone01@ulkyvx.louisville.edu writes:
>I have an IC I need help in identifying.  It is an 8-pin IC with the following
>label:  W03563  9144w4  

The 9144w4 is the date code but none of my books list a W03563.
What is it out of and can you tell us what kind of circuit it is in?

In the odd case that 9144w4 is not the date code, NTE says a 9144-60
is an AM reciever subsystem and a 9144-61 is an FM subsystem, but these
are both in 16 pin packages.

More Info, Please!
Galewn Watts, KF0YJ


Newsgroup: sci.electronics
Document_id: 54255
From: dave@imax.imax.com (Dave Martindale)
Subject: Re: NTSC horiz & vert drive from black burst?

jackp@NETSYS.COM (Jack Powers) writes:
>I would like to hook up some cameras that were recently donated to our
>local community cable TV station which have sync inputs in the form
>of horizontal and vertical drive. Our station sync is a black burst
>which works fine with other boxes with "genlock" style inputs. Can
>anyone point me at a design, article, or whatever showing how to produce
>the horizontal & vertical drive signals?

Check the station's master sync generator.  You'll probably find that
it already has horizontal and vertical drive outputs that just aren't
being used.  A couple of cables and you're in business.

Another possibility is to find a genlockable sync generator with HD and VD
outputs - genlock it to station sync, and then feed HD and VD to the
cameras.

If neither of these is possible, then you'll have to build a sync
separator.  Look at the circuit diagrams of your existing sync generators -
they probably all include circuitry that does what you want.

	Dave

Newsgroup: sci.electronics
Document_id: 54256
From: ruhtra@turing.toronto.edu (Arthur Tateishi)
Subject: Features for answering machines(esp. digital)


Hello, I'm curious what sort of neat features exist on high-end
answering machines today. In particular, I'm interested in
features of digital answering machines. Also, what is the
typical amount of storage(in minutes) for these digital answering
machines?

The reason? I'm hacking together an answering machine program
for my ZyXEL modem and I'm wondering if I'm missing something
on my wish list.

arthur
-- 
"The first fact to face is that UNIX was not developed with security, in any
reliable sense, in mind; this fact alone guarantees a vast number of holes."
    -- "On the Security of UNIX", Dennis M. Ritchie
Arthur Tateishi                 ruhtra@turing.utoronto.ca

Newsgroup: sci.electronics
Document_id: 54257
From: agodwin@acorn.co.uk (Adrian Godwin)
Subject: Re: Laser vs Bubblejet?

In article <1993Apr26.074500.13256@das.harvard.edu> squish@endor.uucp (Shishin Yamada) writes:

# when soaking in water). Lasers are slightly sharper, but the only
# instance where I needed precise layouts was Printed Circuit Board
# Transparencies for PhotoEtching. I found a Textronix color Phaser
# Postscript (Thermal Wax Transfer) to work the best to make PCB
# negatives directly onto a transparency.
# 

Did the deskjet work at all when printing on transparencies ? If it
did, what sort of resolution could it manage ?

-adrian


-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.

Newsgroup: sci.electronics
Document_id: 54258
From: mgc@unislc.slc.unisys.com (Marc Christensen)
Subject: Re: descrambling channels

Sean Oliver (Sean_Oliver@mindlink.bc.ca) wrote:
: I live up in British Columbia, Canada.The cable company I use is called
: Rogers Cable. Does anyone know of their scrambling techniques, and ways of
: getting
: around them? Any suggestions of what they might use?
: 
I don't know the answer to your question, but I am sure Rogers Cable can so
I tool the libery of forwarding your question to them and I am sure they
will be in touch. :-)

Marc Christensen

Newsgroup: sci.electronics
Document_id: 54259
From: ruck@beach.cis.ufl.edu (John Ruckstuhl)
Subject: solvent for duct-tape adhesive?

I know this is a long shot, but does anyone know what solvent I should 
use to clean duct-tape adhesive from carpet?
Someone taped wires to the carpet, and now it is time to move out.

Is the solvent the same as what's used to clean up the goop in coax?
(whatever that is ... but it just barely ties this query into 
sci.electronics)

Thanks for your help
Best regards,
ruck
-- 
John R Ruckstuhl, Jr                    ruck@alpha.ee.ufl.edu
Dept of Electrical Engineering          ruck@cis.ufl.edu, uflorida!ruck
University of Florida                   ruck%sphere@cis.ufl.edu, sphere!ruck

Newsgroup: sci.electronics
Document_id: 54260
From: tas@fermi.clas.Virginia.EDU (Thomas A. Spraggins)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:
>Otherwise, it is technically no problem to connect a foreign
>phone to either the German or Swedish phone system.
>OTOH neither you nor I would ever try that, as it is of course
>illegal.

Oh yes, the good ol' deutsche Bundespost.  Shortly after moving to Germany,
someone told me that "POST" is an acronym for the "Public Organization for
the Suppression of Technology".  Stimmt, oder?

I miss a lot of things about Germany (yes, including the Bier vending
machines at work that were SUBSIDIZED by the firm), but the phone system
is not one of them.

Tom Spraggins
tas@virginia.edu

Newsgroup: sci.electronics
Document_id: 54261
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: Removing battery corrosion

From article <1993Apr25.201129.1239@Princeton.EDU>, by fuchs@tsar.princeton.edu (Ira H. Fuchs):
> Is there a readily available solvent that does a good job at removing the  
> corrosion/encrustation that collects on the battery terminals (usually the  
> cathode) when using alkaline batteries (or more accurately, when NOT using  
> them for a long time)? 
 generally,  the corrosion is a signal that it's time to send them
 of to the recyclers, but if you're that desperate or cheap try 
baking soda and a wire brush. use gloves and goggles, please!

Newsgroup: sci.electronics
Document_id: 54262
From: ree88132@zach.fit.edu (Keith Ledig)
Subject: References for ANY IC

I am looking for a text/reference that will include pinouts, 
description, and functionality for just about any IC made.
Does such a text exist?  Are there docs on the Internet that
reference IC's?  It would be a great idea if each major
IC manufacturer made available to the public an anonymous
FTP site with all it's data books in the form of text files.
(ala RFC style).  This would save time and money for the
IC manufacturer since a text file costs nothing to send
around the world via internet and since most users of
IC's
are found in the internet anyway.  

Are there any books available for purchase that reference
(as many as possible)?  Or am I going to be stuck obtaining
a zillion databooks from the manufacturers (those little
phonebook-type books that are obsoleted every couple years)

:-(



Newsgroup: sci.electronics
Document_id: 54263
From: mbattist@magnus.acs.ohio-state.edu (Mark A Battisti)
Subject: Re: Clear LCD or LED "sheets"

>>An ideal item would be an LED array for which each LED is about 1/2" square.
>>(Yes very coarse)  This is for distance viewing, but on a window.
>>Any pointers of suggestions would be much appreciated.
>
>What, pray tell, are you putting together?  And what about costs?  And does it
>have to be transparent as in totally transparent?  Or just transparent enough
>to allow light from the other side to shine through?

Yes it has to be very clear (like it wasn't there).  And of course, cost is 
always a factor.  I am trying to get an idea of the feasability of such an 
idea.  But I don't want to give too much away.

-Mark

Newsgroup: sci.electronics
Document_id: 54264
From: rowley@netcom.com (Thomas Rowley)
Subject: Re: Voice synth chips

Alltronics in San Jose (408) 943-9773 sells the Votrax Sc-01 Speech Synthesis 
chip for about $5.00. Also I noticed that Radio Shack sells the ISD chip which
 will store small amounts of digitized speech. 

Good Luck




Newsgroup: sci.electronics
Document_id: 54265
From: einari@rhi.hi.is (Einar Indridason)
Subject: Re: How to the disks copy protected.

In <1993Apr26.163640.27632@csus.edu> kschang@sfsuvax1.sfsu.edu (Kuo-Sheng (Kasey) Chang) writes:

>In article <Apr23.223805.66909@yuma.ACNS.ColoState.EDU>
>jmiller@terra.colostate.edu (Jeff Miller) writes: 

>>In an earlier article Kasey Chang wrote:

>>: Nothing, but if you read my WHOLE suggestion, I'm saying that you register
>>: via MAIL by mailing in your registration card, THEN the company send you
>>: the patch which includes the info you put on the registration card.

>>The problem with this scheme, is that when I buy a game, I want to play it
>>*THAT* day...mailing a card to and from California would probably take a week
>>or more.

>I didn't say the program is DISABLED, did I?  (I HATE!!!! it when people
>take my words out of context...)  I mean that once you have installed it,
>you cannot DEinstall it without registering it, or transfer it to another
>machine, or SOME SORT OF LIMITATION (the author will decide), WHICH WILL
>BE REMOVED WHEN THE PROGRAM IS REGISTERED.  


WHAT??!!!!

You can't remove it, unless you register?  
You gotta be joking, right?
What happens if I get a demo-version of that program, install it, and then
decide that I don't like it.  Do I have to register to be able to get rid
of it?  (Hell, no, that is the last thing I would think of!)
If that is what you mean, then you would better make pretty sure, that a
statement to that effect is printed loud and clear on the package!


A better way to implement the above mentioned scheme is (IMHO) to allow
anyone to install the program, but if they register, they get some
additional features enabled.  It could mean only one new .EXE file needed
to be copied, to have got the full-version of the program.
Of course anyone is _free_ to _delete_ or _remove_ that program at whatever
time they like.

Still, we face the trouble of 'moving' the new .EXE file around.  That
could be solved by having the user registering him self, and get back a
specially marked for him (or her) a new .exe file.


As for some sort of limitations, here are some suggestions:
Limit the size of data that the program can work with,
Disable saving the data,
Print it out with some defects in the output (but be sure to mark them as
such)
Let some pop-up screen appear for ca. 10 secs. when the program is started
and/or exited

etc....
but DON'T have it that you _must_ register to be able to remove it.



--
einari@rhi.hi.is

Newsgroup: sci.electronics
Document_id: 54266
From: dp@cec1.wustl.edu (David Prutchi)
Subject: Re: Flexible solar cells

In article <1993Apr22.135517.5897@r-node.hub.org> wayne@r-node.hub.org (Wayne Dawe) writes:
>Two or three years ago I saw a report on TV about a company that had 
>developed a method of making solar cells on a flexible substrate. My
>failing memory has convinced me it was some flexible metal. I now have
>an application that requires a flexible solar cell and was hoping someone
>out in netland knows something about this company or a similar product.
>Any help would be greatly appreciated.
>-- 
>Wayne Dawe                    (pick a path, any path but don't send me
>wayne@r-node.hub.org           anything bigger than 15K)
>wayne@r-node.gts.org   wayne@r-node.pci.on.ca     wayne@r-node.UUCP

Wayne:

Look for these advertised in sailboat supplies catalogs and sail-related
magazines (eg. SAIL ...).

+------------------------------------------------------------+
|  David Prutchi                 HC1DT                       |
|  Washington University         <prutchi@mesun4.wustl.edu>  |
|  Campus Box 1185               <dp@cec1.wustl.edu>         |
|  One Brookings Drive                                       |
|  St. Louis, MO  63130-4899                                 |
+------------------------------------------------------------+

Newsgroup: sci.electronics
Document_id: 54267
From: warren@eggo.csee.usf.edu (Warren Gaiewski)
Subject: Re: D,G,&H type Amplifiers

in article  <735604750.28979.0@unix5.andrew.cmu.edu>,  Mark Yeck
writes:

--------->

Hey, can someone clue me in on these and other weird types of amplifiers?  Just
a brief intro to the concepts behind these would be cool.  I have the clues 
on type A, B, and AB already and stuff, but these other ones are mentioned 
occasionally and I dont know what they do.  I think type D is like a PWM scheme
or something.  Thanx in advanced.

---------->
The whole point to these weird amplifier types is improved efficiency.

Class D amps *are* PWM (pulse width modulation) amps which work very much like
switching power supplies. I think I've seen these things called "class S"
before as well. They're capable of very high efficiencies, and would be suitable
for very high power. I've yet to see anything like this used in an audiophile
amp, though.  I've been trying to design a three-kilowatter for the last year
(to be used as an inverter for an UPS), but have been having serious problems
with layout parasitics (10 IRF 450's in parallel... any help  with a  do-able
isolated drive ckt would be appreciated :) ) 

I'm not absolutely positive about this, but I beleive a 'class G' amp is one that
operates off a variable- or switched power supply rail voltage. The Carver
amps do something like this. They use some sort of phase-control circuit 
(I do not fully understand its operation) to reduce the transformer size, and
I beleive that is patented. I had an M400 apart (trying to fix) and found that
it had three rail voltages that it switched between. I ran a simulation on
PSPICE and found that the topology would greatly reduce power dissipation (heat)
under large-signal conditions, or when driving reactive loads (which draw high
current at the zero-voltage crossings). 

Think SPEAKER.......             /|              Dr. Diode
                              ||/ |           ------|>|------
 "Great sound  starts with    ||  |           warren@eggo.csee.usf.edu
      The Source"             ||\ |           warren@renoir.cftnet.com
                                 \|                




Newsgroup: sci.electronics
Document_id: 54268
From: u95_dgold@vaxc.stevens-tech.edu
Subject: EMI filter, What's in it?

Could someone tell me what's in a Cornell-Dubilier EMI Filter
FIL 3363-001?

It is rated at 13A 115/250VAC 50/60HZ.  Is it just MOV's and ferrite?

Dave  /  n2mxx
Stevens Institute of Technology
Hoboken, New Jersey

Newsgroup: sci.electronics
Document_id: 54269
From: alung@megatest.com (Aaron Lung)
Subject: Re: how to get rid of flyback whine?

In article <1993Apr26.012517.23391@Princeton.EDU> jsm@shade.Princeton.EDU (John Scott McCauley Jr.) writes:
>I recently took apart my color Sony TV to clean the volume pushbuttons and
>when I put the beast back together, the flyback whine got much louder.
>
>Is this easy to fix? Which part is resonating? I have heard rumors of a
>spray that will fix the noise.  Is this a simple thing for a TV repairman
>to fix?
>
>	Thanks,
>
>		Scott

Ah-ha!  I'm not alone at last!  Which Sony do you have??  I have a
27"SXR (pre-XBR series, circa 1987).  That damn thing used to
make noise like a mad-man.  I had/have 2 separate problems...one being the
flyback, the other was the assembly where the windings of the yoke
came together. 

First:  I found by poking around the windings on that assembly,
the thing would make noise.  I guess that there was enough of a potential
in that assembly to leak, so I sprayed it with a dielectric insulation
spray--I think it was urethane or acyrilic.  That fixed it.

Second:  Flyback...for the life of me, I can't isolate this one.  If I
leave the cover off, the TV will be quiet.  If I put the cover back on,
and let it heat up, it'll start to whine--kinda hard to solve with the
cover on!! :-(

A friend of mine who used to fix TV's says there might be a pin-hole
leak somewhere on the flyback.  Usually it's surrounded by a bunch of
black dust/dirt.

I hope this is a start...if you find something out, let me know!

aaron


Newsgroup: sci.electronics
Document_id: 54270
From: iturriag@utkvx.utk.edu (Mr. Y)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de>, wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes...
>In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:
> 
>> I'm wondering if I can tote my American touch tone phone around with me
>> to Sweden and Germany.  It's DC powered, and I can buy a special adapter
>> for that in Europe.  The question is if the general electronics work
>> the same.  I can buy a different wall plug and refit it (I'm sure I'd
>> have to), but would that do the trick?
> 
>Two things to watch for:
>In Germany (and I think the same holds for Sweden) only some
>of the connections can handle tone dialing, so make sure the
>phone can be set to pulse dialing.
>In Sweden, the '0' is the first digit and all other digits
>are pushed "down" by one position; this makes dialing (and
>in the process converting numbers) an interesting task.
>Otherwise, it is technically no problem to connect a foreign
>phone to either the German or Swedish phone system.
>OTOH neither you nor I would ever try that, as it is of course
>illegal.
>-- 

I am not quite so sure about the illegality of using a regular American phone
on your home system. I vaguely remember a few years ago, when "Deutsche
Bundespost" split into Postdienst, Postbank, and Telekom there was some
discussion about a new regulation. I know that cordless or cellular phones
still have to be approved by the Telekom, but does that hold true for regular
phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use
touch-tone dialing. I assume, however, that most areas are still exclusively
set to pulse dialing. Last time I checked (Jan '93) the Cologne areacode 221
was still solely pulse dialing.

BTW, touch tone does become more common in Germany, bringin with it the
flourishing of 1-900 services (in Germany 0190). I just hope we'll all have
ISDN some time at an affordable price - idle wishes...

Markus Iturriaga                
                           "Things go smoother with lard!"
iturriag@utkvx.utk.edu       "Bring back the glory that was grease!" 
iturriag@utkvx.bitnet           -East Tennessee Lard Advisory Council  

                            MILLARD FILLMORE LIVES!   

===============We've=got=what=it=takes=to=take=what=you've=got.=================

Newsgroup: sci.electronics
Document_id: 54271
From: fennell@well.sf.ca.us (Michael Daniel Fennell)
Subject: Re: Why circuit boards are green?


Why are circuit boards green?  The material used to make them goes by two
names.  If it is used to make circuit boards it is called FR-4.  The same
material is used in the cryogenics industrya and marine industries as a
structural material and is called G-10.  FR-4 and G-10 are both green.  They
are not green because of a solder masking agent.  The basic ingredients are
a clear epoxy resin and glass fibers.  I am not sure what the specs are on
the resin, but if you are really curious you can call NEMA (National
Electronics Manufacturing Association) or Ciba Geigy (a major manufacturer
of epoxy resins) to find out.  As an aside, I occasionally mix clear epoxy
and glass microsphres to cast small structures for cryogenics experiments.
The proportions of glass to epoxy are about the same as in G-10.  They are
the same green color.

Newsgroup: sci.electronics
Document_id: 54272
From: mdgoodma@apgea.army.mil (Malcolm D. Goodman <mdgoodma>)
Subject: Fiber Optic Modems For Sale *** CHEAP ***

OK I sold all but these, I had some offers and I accepted an offer
of 25.00 for the pair from bdale@gag.com ( Bdale Garbee ).  I don't
know what happened to him but he won't reply now that I accepted
it so I'll offer these again.
> 
> PLease take these and use them.  Take advantage of me... I really
> don't know what they are worth.
> 
> Qty 2  -  Canoga Perkins Fiber Optic Modems, Model 2250, RS-422
>           Interface, appear new.  I have powered up but that's all,
>           I have not used them and I cannot tell you whether they
>           work or not.    
>                                  Make Offer.........
> 
> Thanks and please buy this stuff or it goes out the door
> 
> Mack
> mdgoodma@cbda8.apgea.army.mil
> ..


Newsgroup: sci.electronics
Document_id: 54273
From: mcmahan@netcom.com (Dave Mc Mahan)
Subject: Re: References for ANY IC

 In a previous article, ree88132@zach.fit.edu (Keith Ledig) writes:
>I am looking for a text/reference that will include pinouts, 
>description, and functionality for just about any IC made.
>Does such a text exist?  Are there docs on the Internet that
>reference IC's?  It would be a great idea if each major
>IC manufacturer made available to the public an anonymous
>FTP site with all it's data books in the form of text files.
>(ala RFC style).  This would save time and money for the
>IC manufacturer since a text file costs nothing to send
>around the world via internet and since most users of
>IC's are found in the internet anyway.  
>
>Are there any books available for purchase that reference
>(as many as possible)?  Or am I going to be stuck obtaining
>a zillion databooks from the manufacturers (those little
>phonebook-type books that are obsoleted every couple years)

We use a CD-ROM based system here.  There are about 45 CD-ROM disks and a
4-disk changer hooked to a dedicated MS-DOS computer.  It contains scanned
images of data book pages for several thousand parts.  When you ask it for
something it knows about (mostly active IC parts), it works quite well.
THey don't handle all the varieties of transistors or diodes that exist.
It is definately a start in the right direction, but they need to expand
the data base to handle more types of stuff.

These systems aren't cheap.  We paid about $7,000 for the liscence and get
monthly updates of some of the CD-ROM disks.  We send the old ones back to
them so that they will keep sending us the updates.  I think we pay a
yearly maintainence fee of about $1,500 to get the updates.

If you find the part you want, you can look at the data sheet on a
page-sized monitor (it's a special monitor from SigmaSystems).  You can
also print each page of the datasheet you want on a LaserJet printer.  Page
printing takes a couple of minutes per page.  It can take a while to dump
the 5 or 6 pages you usually need.

I have a feeling the maker wouldn't like it if we made the data available
to all Internet users.    :-)

  -dave

-- 
Dave McMahan                            mcmahan@netcom.com
                                        37N 17.382    121W 59.190 

Newsgroup: sci.electronics
Document_id: 54274
From: Christopher Kristof <ck3i+@andrew.cmu.edu>
Subject: ??? Mystery Part ???

    I have a mystery part labeled NEC AC100.  It's from the low voltage
supply of an NEC Multisync I monitor.  It's a three lead part in a
square package like a volate regulator or power transistor.  The board
is labeled CR691 where the part goes.  (Possibly an SCR?)  The pin
labeled G on the board goes to a zener diode (reference voltage?); the
pin labeled T1 goes to the negative lead of a capacitor in the power
supply, and the pin labeled T2 goes to the negative side of the bridge
rectifier in the supply.

    If anyone can tell me what this is, or better yet, where I can buy
one just like it, please email me at ck3i@andrew.cmu.edu.  I've called
NEC's "monitor repair number" and not only do they not know what the
part is, but they don't think that they can find one to sell to me... 
It makes no sense to me...

Thanks

Newsgroup: sci.electronics
Document_id: 54275
From: johng@socrates.umd.edu (John Gustafson)
Subject: Re: solvent for duct-tape adhesive?

ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?

May I tease out a sub-thread from this discussion?

Can you all please tell me how to remove  the stickers from new houses'
appliances and outdoor lampposts?  Especially the lamppost, right on
the glass.  Isn't there something you can rub into stuck-on labels that
will release them from their death-grip on glass or other hard surfaces?

Many thanks for any help.  

                                              John

John Gustafson   johng@socrates.umd.edu


Newsgroup: sci.electronics
Document_id: 54276
From: malmedal@ulke.dhmolde.no (Terje Malmedal)
Subject: Ranger2.0 shareware


Hello.

  The last issue of Electronics world describes Ranger 2.0 a PCB CAD program.
According to the article there is a crippled version available as shareware,
does anybody know of any FTP sites/BBSes where this program may be found?

Thanks in advance.
--
 - Terje
malmedal@unix01.dhmolde.no

Newsgroup: sci.electronics
Document_id: 54277
From: advax@reg.triumf.ca (A.Daviel)
Subject: Re: How universal are (video) phones these days?

Just saw an article in New Scientist; AT&T videophones won't talk to (?)BTI 
videophones. The AT&T ones use a 19.2kb modem, BTI uses 14.4kb. AT&T models 
have to communicate using all AT&T exchanges, whereas the BTI can route 
via most current exchanges. Suggestions include building standards converters 
into telephone exchanges - the mind boggles :)= . The BTI design is a bit 
more conservative and is better able to cope with current data compression 
hardware on long-distance lines.

(not having the magazine to hand, I may have mis-remembered BTI. I think it
is a British one made by GEC-Marconi, and currently selling to other
countries). 

Yet Another Standards Screw-up.

--
 Andrew Daviel, Vancouver, Canada <advax@triumf.ca>
  finger advax@reg.triumf.ca for PGP key

Newsgroup: sci.electronics
Document_id: 54278
From: bsc_graham@vd.seqeb.gov.au
Subject: FM Transmitter ICs- Help!!!!!

I am trying to design a small 90mW 472MHz FM transmitter for remote alarm
use.

Is there an FM transmitter IC available that can be used for this purpose?

Any help, circuits, info etc will be greatfully accepted.

Please reply to bsc_graham@seqeb.gov.au

Thanks in advance.

Graham Castledine.


Newsgroup: sci.electronics
Document_id: 54279
From: vanderby@mprgate.mpr.ca (David Vanderbyl)
Subject: Re: Lead ACid Batteries Part 2!!!

>The lead-acid secondary cell releases energy (electricity) with the following
>chemical reaction:
> 
>Pb + PbO2 + 2H2SO4 --> 2PbSO4 + 2H20
> 
>Lead and Lead (IV) Oxide and Sulfuric Acid produce Lead Sulfate and Water
[heats of formation deleted]
>The heat of reaction at 25 C is therefore -60.6 kcal per mole PbSO4 produced.
>Note that lead sulfate is not very soluble (0.0048 grams per 100 grams water
>at 25 C), and it will thus precipitate out of solution where the reaction is
>occurring, or the cathode (positive terminal) of the battery.  (I am almost
>sure it is the positive terminal where the precipitate forms, but I may be
>wrong.  Oh well, I don't have a corroded battery to corrobate, and I don't feel
>like thinking through it right now.)

The major problem with this is that the reaction takes place in an ACID solution.
PbSO4 is soluble in an acid solution and will not precipitate out.  Also, H2SO4
is in a water solution as 2H30+ and SO4--.  Thus the heats of formation of
PbSO4 and H2SO4 are for the most part irrelevant.

>What is important to notice here is that the reaction, as you knew it would be,
>is exothermic, or energy discharging.

As it turns out the reaction is indeed exothermic (heat producing).
(More about this later.)

What actually happens to make the battery completely useless is this:
(we're talking lead-acid batteries of course)
The battery slowly self discharges.  As this discharge takes place two things
happen. -The level of Pb++ ions in the acid solution increases (i.e. the lead
           and lead oxide plates are dissolved).
        -The level of H30+ ions in the acid solution decreases (i.e. the solution
           becomes less acidic, or more like water if you like).
Now, as the post to which I am responding correctly stated, PbSO4 will precipitate
in a WATER (non-acid) solution.  When the battery dies (i.e. is fully discharged)
we end up with a high concentration of Pb++ and SO4-- in water.  So PbSO4
forms in the solution and FALLS TO THE BOTTOM OF THE BATTERY (of course this
happens in varying degrees, the more discharged, the more precipitate forms).

The precipitate forms a conductive layer on the bottom of the battery.  If
there is enough of the lead and lead oxide plates left to touch the precipitate
(more common in a newer battery) a dead short results.

I have seen products in automotive shops to correct this condition, but they
are for the most part useless.  They can dissolve the PbSO4 but cannot restore
the lead and lead oxide plates properly.  You may have some success with
these products for a newer battery.

[stuff deleted]
>To understand why lead-acid batteries DO INDEED discharge faster when stored on
>concrete as opposed to wood or earth (dirt), one should recall LeChatelier's
>Principle, which can be paraphrased as:  anything subjected to some stress will
>act to move to a more comfortable position.  Here are the thermal conductivities
>of a some selected materials:
[stuff deleted]
>This is where LeChatelier's principle comes into play.  Removing energy from
>the exothermic reaction will drive the reaction further to completion.  If the
>reaction normally occurs at room temperature, keeping the battery at that
>temperature requires the removal of any heat produced.  A concrete surface is
>a better heat sink than a dirt or wood surface.  Store a battery in the corner
>of a poured concrete basement, and you have 3 surfaces removing energy, which
>"pulls" the reaction along.

This stuff is just made up by the author and is completely invalid.
In fact the discharge reaction takes place at a higher rate at higher
temperatures.  A logical consequence of the above argument is this:
"If you really want your car to start, lower the battery temperature to
 -50 to 'pull' the reaction along."  We all know from experience (at
 least those of us in Canada do (it gets cold up here)) that this is
not true.  If we want to start our car on a really cold day we warm
the battery.

(Besides which, there is not enough energy released through self discharge
 to appreciably raise the temperature.  The air would amply dissipate any
 such heat, whether the bottom of the battery was insulated or not.  This
 is of course irrelevant, since you would WANT the battery to be cool
 during storage.)

Just keep the battery in a cool dry place and keep it charged!


Newsgroup: sci.electronics
Document_id: 54280
From: pierson@cimill.enet.dec.com (Dave Pierson)
Subject: Re: PCMCIA

In article <1d.11083.3287.0NAC6CC5@synapse.org>, martin.vuille@synapse.org
(Martin Vuille) writes...

>Does anyone know who to contact to obtain a copy of the PCMCIA standard?

	PCMCIA
	1030G East Duane St
	Sunnyvale, CA 94086 USA
	408-720-0107

	See also:
	alt.periphs.pcmcia

thanks
dave pierson			|the facts, as accurately as i can manage,
Digital Equipment Corporation	|the opinions, my own.
40 Old Bolton Rd		|I am the NRA
Stow, Mass 01775 USA		|pierson@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing."  A J Raffles

Newsgroup: sci.electronics
Document_id: 54281
From: wesw@sr.hp.com (Wes Whiteley)
Subject: Re: solvent for duct-tape adhesive?


I have used a product called "Goof-off" it comes in a little yellow 
can (about the size of a deck of playing cards).

It has worked well for removing all kinds of sticker and tape residues.

NOTE: always test a small area in an inconspicuous place before using.  

Good luck,



Wes Whiteley
(707) 577-5292
wesw@sr.hp.com

Newsgroup: sci.electronics
Document_id: 54282
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Pre-fab PC case/power supplies and CSA/UL/FCC stuff

What kind of CSA/UL/FCC approval do $60+ mail-order PC computer
cases and power supplies have?  

Can I assume that the certification process for small-scale custom hardware
(ie digital/analog circuitry) is reduced, or even eliminated, if I use
such a case and (certified) power supply?

Also, assuming that I use a "certified" power supply, have I satisfied the
requirements of CSA/UL approval, and possibly FCC approval as well?
Do mail-order PC cases satisfy FCC certification?  Is FCC certification
even necessary for scientific (non-commercial/non-residential) use?

Newsgroup: sci.electronics
Document_id: 54283
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: solvent for duct-tape adhesive?

ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

At least locally, many shops carry a product called Goo Gone.  It works well
on scummy-gummy-sticky-goop-that-won't-go-away...  As always, color test in
an inconspicuous corner before use.

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 |  Happiness is suspending X-Wings to make an appointment
+1 818 449 5457    |  calendar entry and to send a fax, and resuming the game.

Newsgroup: sci.electronics
Document_id: 54284
From: dhollman@phage.cshl.org ( CSHL)
Subject: Re: How to the disks copy protected.

I still think a major point is being missed... If you are worried about
software pirates, NOTHING will stop them. These are people who crack
software (mostly games, but so what) daily for fun. They can usually find
a crack around anything, especially if the manufacturer leaves a hole for such a thing.

-- 
|-----------------------------------------------------------------------------|
|    Are we having fun yet?                                                   |
|-----------------------------------------------------------------------------|

Newsgroup: sci.electronics
Document_id: 54285
From: scotts@bbking.FtCollinsCO.NCR.COM ( Scott Sherman)
Subject: Re: Radar/Laser Detectors

In article <GORNISH.93Apr26111045@sp1.csrd.uiuc.edu>, gornish@sp1.csrd.uiuc.edu (Edward H. Gornish) writes:
|> What are people's opinions about laser detectors?  Escort makes a
|> laser detector, the Passport 1000, and claims it works fine.  However,
|> I've talked to some people who have said that it will only work if you
|> are lucky - i.e. if the cop happens to point his laser at a car in
|> front of you, and the laser beam happens to reflect back to your
|> detector.  Otherwise it won't work.  Regular radar, of course, travels
|> in all directions; hence it is more detectable.  Any comments?
|> 
|> Escort has a deal (till the end of April, I think), where if you buy
|> their wideband (Passport 3200 - X, K, Ka) and laser detectors, you'll
|> save $60 off of buying them separately.  In this case, the addition of
|> the laser detector over the Passport 3200 is only $40 (i.e. Passport
|> 1000 normally costs $100).

Uniden makes an all in one unit (X, K, Ka, Laser) for about $130.
Colorado Radar sells passive radar jammers, the passive supposedly being legal,
for about $100. wont help you with Laser however.

Scott

Newsgroup: sci.electronics
Document_id: 54286
From: u95_dgold@vaxc.stevens-tech.edu
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu>, johng@socrates.umd.edu (John Gustafson) writes:
> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
> 
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
> 
> May I tease out a sub-thread from this discussion?
> 
> Can you all please tell me how to remove  the stickers from new houses'
> appliances and outdoor lampposts?  Especially the lamppost, right on
> the glass.  Isn't there something you can rub into stuck-on labels that
> will release them from their death-grip on glass or other hard surfaces?
> 
> Many thanks for any help.  
> 
>                                               John
> 
> John Gustafson   johng@socrates.umd.edu
> 

Try WD-40

Newsgroup: sci.electronics
Document_id: 54287
From: reid@ucs.indiana.edu (Frank Reid)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu> johng@socrates.umd.edu (John Gustafson) writes:
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
>
>May I tease out a sub-thread from this discussion?
>
>Can you all please tell me how to remove  the stickers from new houses'
>appliances and outdoor lampposts?  Especially the lamppost, right on
>the glass.  Isn't there something you can rub into stuck-on labels that
>will release them from their death-grip on glass or other hard surfaces?

"Petroleum naphtha," available at most hardware stores, will remove most
adhesives.

--

Frank     reid@ucs.indiana.edu

Newsgroup: sci.electronics
Document_id: 54288
From: yxy4145@ucs.usl.edu (Yu Yingbin)
Subject: Does any one know what is the biggest ROM for present ?

         Please replay to : yxy4145@usl.edu
                                  Thanks a lot


Newsgroup: sci.electronics
Document_id: 54289
From: gvolk@nyx.cs.du.edu (Greg Volk)
Subject: Re: solvent for duct-tape adhesive?

What I usually use...and this stuff is only good on glass....is either Acetone,
or a little Benzene. The latter of the two is a bit dangerous (possibly a 
carcinogen(sp?)) but it usualy gets the job done. I imagine you can you the two
solvents on most metals as well as glass, but keep the stuff away from plastic.
Better yet, you may just want to go to your local hardware store and ask them
what they use. 

Newsgroup: sci.electronics
Document_id: 54290
From: eldred@rrunner.jpl.nasa.gov (Dan Eldred)
Subject: Re: solvent for duct-tape adhesive?

In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?
>Someone taped wires to the carpet, and now it is time to move out.
>
I don't know for sure that this will work, but you might try MEK (methyl
ethyl keytone?).  It worked getting the stickum left over from shelf paper,
and is available at paint stores.  Use a carbon gas mask and lots of
ventilation--this stuff really stinks!

	- Dan


Newsgroup: sci.electronics
Document_id: 54291
From: mxmora@unix.sri.com (Matt Mora)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.210417.2984@socrates.umd.edu> johng@socrates.umd.edu (John Gustafson) writes:
>ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:

>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?


I use WD-40.


>May I tease out a sub-thread from this discussion?

>Can you all please tell me how to remove  the stickers from new houses'
>appliances and outdoor lampposts?  Especially the lamppost, right on
>the glass.  Isn't there something you can rub into stuck-on labels that
>will release them from their death-grip on glass or other hard surfaces?

>Many thanks for any help.  


Try WD-40.





Xavier







-- 
___________________________________________________________
Matthew Xavier Mora                    Matt_Mora@qm.sri.com
SRI International                       mxmora@unix.sri.com
333 Ravenswood Ave                    Menlo Park, CA. 94025

Newsgroup: sci.electronics
Document_id: 54292
From: mxmora@unix.sri.com (Matt Mora)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

In article <1993Apr25.223611.1@auvax1.adelphi.edu> schmidt@auvax1.adelphi.edu writes:

>platen, etc flew across the room, and several people in the room almost had
>heart attacks.  Beware the explosive properties of WD40 vapor.
>


We use it as starting fluid for jet ski's. The fact that its a lubricant 
works very well since jet ski's are 2 cycle. It also helps when a ski
floods with water because we clean the spark plus with the stuff.


OB sci.electronics:


I have an office/studio in my garage with a phone in it. Our wireless phone
has a page feature where you can make the phone or hand set ring to get
the attention of the other person. Is there a simple circuit that I can use
over the second pair of wires (or the first pair) to emulate this effect
with the phone in the garage? (ie push a button to make the phone ring in the
house or push a button to make it ring in the garage.)



Thanks


Xavier
 
-- 
___________________________________________________________
Matthew Xavier Mora                    Matt_Mora@qm.sri.com
SRI International                       mxmora@unix.sri.com
333 Ravenswood Ave                    Menlo Park, CA. 94025

Newsgroup: sci.electronics
Document_id: 54293
From: whit@carson.u.washington.edu (John Whitmore)
Subject: Re: 8x oversampling CD player

In article <mcmahanC5v942.MKJ@netcom.com> mcmahan@netcom.com (Dave Mc Mahan) writes:
> In a previous article, kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>In article <hcbC5un9L.DD0@netcom.com> hcb@netcom.com (H. C. Bowman) writes:
>>>
>>>I just bought a new portable CD player for the office, and I notice that
>>>it proudly proclaims "8 TIMES OVERSAMPLING" on the box. 

>>The data is only ever read once (barring mistracks and such, of course),
>>and eventually gets turned into 44.1 KHz, 16 bit, two channel data.
>>Oversampling takes two discrete data points, and interpolates n-1 points
>>between them for n times oversampling.  When I asked, people said that the
>>interpolation was not simply linear interpolation, but significantly more
>>complicated.

>You are quite correct in your understanding.

>In case you care, the filtering method uses an FIR (finite impulse response)
>filter.  I'd guess that CD makers use the same kind of method.  Anybody out
>there know the real answer? 

	Typical (in the old 2x-oversampling units) was a thirteen-tap
FIR, implemented as a dedicated hardware addition circuit.  At this kind
of speed (slow, by digital standards) such an adder is much less
expensive than analog components of comparable precision.

	I gleaned this information from a hardware manual for
an old CD player design; where one would find similar info for
a particular CD (the digital filter IS an interesting component,
from my point of view), I have no idea.  The digital filter
is a kind of interpolation scheme (read a book on numerical 
analysis, to see just how BROAD the term 'interpolation' is...),


	John Whitmore



Newsgroup: sci.electronics
Document_id: 54294
From: michael@chpc.utexas.edu (Michael Lemke)
Subject: Re: How universal are phones these days?

In article <26APR199315293014@utkvx.utk.edu> iturriag@utkvx.utk.edu (Mr. Y) writes:
[...]
>
>I am not quite so sure about the illegality of using a regular American phone
>on your home system. I vaguely remember a few years ago, when "Deutsche
>Bundespost" split into Postdienst, Postbank, and Telekom there was some
>discussion about a new regulation. I know that cordless or cellular phones
>still have to be approved by the Telekom, but does that hold true for regular
>phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use
>touch-tone dialing. I assume, however, that most areas are still exclusively
>set to pulse dialing. Last time I checked (Jan '93) the Cologne areacode 221
>was still solely pulse dialing.
>
>BTW, touch tone does become more common in Germany, bringin with it the
>flourishing of 1-900 services (in Germany 0190). I just hope we'll all have
>ISDN some time at an affordable price - idle wishes...
>

Does this imply the German tone dialing is compatible with the American 
one?  I know at least the British system is not -- it is supposedly close 
enough though that an American phone will work.  But my modem (American)
has a special setting for British standards...

Michael
-- 
Michael Lemke
Astronomy, UT Austin, Texas
(michael@io.as.utexas.edu or UTSPAN::UTADNX::IO::MICHAEL [SPAN])

Newsgroup: sci.electronics
Document_id: 54295
From: flux@inqmind.bison.mb.ca (John Kamchen)
Subject: VGA circuit

I've come across a circuit from Integrated Circuit Systems Inc
called a GSP500.   This chip genlocks a VGA card to a dual input
NTSC signal.  
The output from this chip is basicly a pixel clock, and has various 
speeds.  I notice that it outputs a 28mhz clock..  can this output be 
used on an Amiga system?
And must it be NTSC/VGA  or can it be NTSC/NTSC  ?
 
Any simple circuits to boost an NTSC to a VGA signal?
Need to genlock a laser disc to my 31khz video.
-John


flux@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

Newsgroup: sci.electronics
Document_id: 54296
From: Mike Diack <mike-d@staff.tc.umn.edu>
Subject: FREE! EPROM eraser/PCB exposer(Twin cities collect)

This inelegant device started life as a 175 watt security lamp, until
i smashed off the outer glass to liberate the nasty rays, It works a
treat, weighs a heap (due to the ballast) , and NO - i wont ship it !!
cheers
Mike.

Newsgroup: sci.electronics
Document_id: 54297
From: wa2ise@netcom.com (Robert Casey)
Subject: Re: Cable TVI interference

If I remember rightly, there is a pulsating set of tones piped thru the CATV
systems (somewheres near the FM broadcast band).  And that the cable company
trucks listen for this as they roam around town.  If you can hear it over
the air and not cable....

Newsgroup: sci.electronics
Document_id: 54298
From: nilesh@shakti.ncst.ernet.in (Nilesh Parikh)
Subject: HELP : Wanted Pinouts of OKI 58321, RTC

Can anybody send me Pinouts of Real Time Clock IC of OKI Semiconductors,
58321. I wish to know if any RTC IC of OKI has an inbuilt crystal rather
than an external 32.768KHz crystal.
Thanks in advance.
Nilesh Parikh
nilesh@shakti.ncst.ernet.in


Newsgroup: sci.electronics
Document_id: 54299
From: blockley@csu.murdoch.edu.au (Adrian Blockley)
Subject: Programming Motorola XC68HC705P9?

Has anyone successfully programmed this beast using the bootloader pgm
with the circuit described in `the little green handbook, pg 9-1`?

Dan.
--

----------------------------------------------------------------------
Adrian Blockley                    ! I may say something profound   
Environmental science              ! here one day.                  
Murdoch University                 !                          
Western Australia, 6153            !                               
blockley@essun1.murdoch.edu.au     !                                
phone 09-360 2737                  !
----------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54300
From: lc@goanna.cs.rmit.oz.au (leon)
Subject: Re: 2% silver solder

In article <199304251131.AA08572@dec3100a> shiekh@ictp.trieste.it (Andy Shiekh) writes:
>
>  I have seen the existance of electronics solder with a 2% silver
>content that seems to have good wetting and fatique reatings.
>  Can anyone tell me why it is not used? (silver is not such an expensive
>metal).
>
From "Management of Electronics Assembly" (Ian Oakes)
After talking about 63/37 tin lead alloy and the eutectic point...
"Occasionally, impurities may be added to solder, to vary charactersitics 
within the soldering process in an attempt to improve performance.  For
example, addition of small quantities of antimony and copper can reduce
the amount solder moves under stress when solid.  For particular
applications additions of impurities may be warranted but, in general, it
is best to keep the solder used in a soldering process as pure as possible."

I guess this is the good oil for commercial operations, but it doesn't
mention anything esoteric.

leon


Newsgroup: sci.electronics
Document_id: 54301
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: solvent for duct-tape adhesive?

From article <1993Apr27.004240.24401@csi.jpl.nasa.gov>, by eldred@rrunner.jpl.nasa.gov (Dan Eldred):
> In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>>I know this is a long shot, but does anyone know what solvent I should 
>>use to clean duct-tape adhesive from carpet?
>>Someone taped wires to the carpet, and now it is time to move out.
>>
> I don't know for sure that this will work, but you might try MEK (methyl
> ethyl keytone?).  It worked getting the stickum left over from shelf paper,
> and is available at paint stores.  Use a carbon gas mask and lots of
> ventilation--this stuff really stinks!
> 
> 	- Dan
> 

For those who don't know, methyl ethyl ketone is more commonly known 
as ACETONE and can be found as the major active ingredient in
NAIL POLISH REMOVER.  YOUR WIFE'S PROBABLY GOT SOME HANGIN' AROUND....

Newsgroup: sci.electronics
Document_id: 54302
From: erickson@azure.nmt.edu (Alan Erickson)
Subject: PC parallel I (!= I/O)

	I'm trying to bring in 8+ bits to a PC, and would like
	to use interrupt-driven routines. Without buying an IO
	board or making a new port, _where_ can I bring in these
	bits? LPT seems to have only a few inputs, but I've heard
	rumours that some LPTs have bidirectional lines. Anybody
	know fer sure? If any bi-d LPTs, which boards have them
	(I'll be running a new 386DX-33)?

------------------------------------------------------------------
Alan Erickson   erickson@baltic.nmt.edu		

to all SunRayce '93 competitors: I hope you're getting
about as much sleep as I am.....
------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54303
From: jimt@ee.mu.OZ.AU (Jim Trivellas)
Subject: * HELP needed with LIGHT DEPENDENT RESISTOR Devices (LDRs) *

Can some kind soul provide me with information on LDRs that contain an
onboard light-source, in a totally integrated and light-shielded unit.

I have seen a VTL5C LDR in some schematics.  So who are the manufacturers
of these devices, and what are the different types.

Thanks very much in advance,
Jim.

-------------------------------------------------------------------------------
  Jim Trivellas.
  Department of Electrical & Electronic Engineering.
  School of Information Technology & Electrical Engineering.
  The University of Melbourne, Parkville 3052, Victoria, Australia.
                  |
                  |
                  |			Telephone: +61 3 3447976
                *****			Email: jimt@mullian.ee.mu.oz.au
     _______*************_______
   _|_____*****************_____|_
 _|_|_____*****************_____|_|_	"Hello, is that the front desk?"
| | ________*************________ | |			Allan Holdsworth
|  |            *****            |  |
   |          The  SPID          |
-------------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54304
From: jtsilla@damon.ccs.northeastern.edu (James Tsillas)
Subject: Re: How universal are phones these days?


I sent a 2400 baud modem to a cousin in Greece from the U.S. and it is
working fine for him. It also worked for me in U.S.

-Jim.

--
	***  James Tsillas  jtsilla@damon.ccs.northeastern.edu   ***
	***      Work: (508)898-2800, Home: (617)641-0513        ***
	***        "He is after me. Jim is after him."           ***
	***            - Hop on Pop, Dr. Seuss                   ***

Newsgroup: sci.electronics
Document_id: 54305
From: mpoly@panix.com (Michael S. Polymenakos)
Subject: Re: How universal are phones these days?

In <LHE.93Apr26131014@yang.sics.se> lhe@sics.se (Lars-Henrik Eriksson) writes:

>Most (if not virtually all) swedish exchanges can handle tone
>dialling. Many older electromechanical exchanges have been modified
>accept tone dialling.

 I would not be suprised if the equipment is compatible, in fact New York
Telephone (NYNEX) spend a lot of money on Swedish switching equipment
recently.

>Lars-Henrik Eriksson                            Internet: lhe@sics.se

 You can guess what brand of equipment I refer to :-)

Michael
-- 
______________________________________________________________________________
             In this land, said the god; "who seeks shall find; 
        Who sits with folded hands or sleeps is blind." - Sophocles

Newsgroup: sci.electronics
Document_id: 54306
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

I wrote:

: : bit of it, you could take the tape over to a local ham operator's house
: : and ask him for his opinion of what you're hearing.  Most communities
: 
: You cannot do that legally. However, you can ask a ham over to listen.
: If the interference occurs at a specific time each day, then it would
: be possible to do such scheduling.  If nothing else, you could invite
: the ham over to transmit from your driveway, to see if he interferes.
: If he does, then you probably need to have your equipment worked on to
: make it immune to rf interference.

As a coupld of people have pointed out - this is wrong. It is not illegal
to record or disclose what you heard on the Ham bands. 

Bill

Newsgroup: sci.electronics
Document_id: 54307
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Power, signal surges in home...

galen@picea.CFNR.ColoState.EDU (Galen Watts) writes:
: 
: Why can't he record it legally?  It may not be admissable in court, but
: recording for personal use is legal.  If he wants to play it for his ham
: friend, that's legal too, as long as he doesn't charge admission.

Yeah - I goofed - a slip of the mind. I must be getting senile.

... deleted ...

: Hey Bill, where were you three weeks ago when all this stuff was posted
: and dealt with?

Busy posting on about 20 other groups. I get to this one about once every
three months or so. 

Bill

Newsgroup: sci.electronics
Document_id: 54308
From: jvannes@vms.macc.wisc.edu
Subject: Re: Long distance IR detection

In article <1993Apr24.064907.22281@ennews.eas.asu.edu>, gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan) writes...

>I designed and built hardware in 1988 that would output a logic level (from
>a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
>Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
>variations in sunlight (and 60Hz from lights). Used no lenses.
> 
>Allen Sullivan

I would be interested in knowing more about the sensing hardware.  What did
you use for the detector?  Could you detect the angle of location, or did
the system simply respond to the presence of the transmitter in the sensors
field of view?

Newsgroup: sci.electronics
Document_id: 54309
From: tsar.Princeton.EDU!fuchs (Ira H. Fuchs)
Subject: Re: Removing battery corrosion

In article <1993Apr26.165902.239@uvm.edu> me170pjd@emba-news.uvm.edu.UUCP  
(Peter J Demko) writes:
> From article <1993Apr25.201129.1239@Princeton.EDU>, by  
fuchs@tsar.princeton.edu (Ira H. Fuchs):
> > Is there a readily available solvent that does a good job at removing  
the  
> > corrosion/encrustation that collects on the battery terminals (usually  
the  
> > cathode) when using alkaline batteries (or more accurately, when NOT  
using  
> > them for a long time)? 
>  generally,  the corrosion is a signal that it's time to send them
>  of to the recyclers, but if you're that desperate or cheap try 
> baking soda and a wire brush. use gloves and goggles, please!

Sorry, I meant the terminals in the device not on the batteries (which are  
obviously quite dead).

Newsgroup: sci.electronics
Document_id: 54310
From: ynecgan@sx.mont.nec.com (Greg Neill)
Subject: Wanted: source for tuning capacitors


Hello there.  The other day I was feeling a tad nostalgic and thought
about constructing an old-time crytal radio set.  I figured on
substituting a modern germanium diode for the crystal, and winding the
antenna coil, etc., myself.

The only problem I seem to have is in locating a source for a tuning
capacitor -- you know, the old meshed-plate variable condensers which
used to be the mainstay for tuning circuits.  Well these things seem to
be all but extinct in their original catalog habitats.  Trimmer
capacitors are relatively abundant, but are not really suitable for this
application.

So, can anyone point me to a supplier of tuning capacitors in the 
0--360 pF range?

Manythanks.

-- 
------------------------------------------------------------------------------
Greg Neill,               | ounce (ouns), n. - The standard unit of
HNSX Supercomputers   Inc.|   prevention, equal to one pound of cure.
gneill@cid.aes.doe.ca     | 

Newsgroup: sci.electronics
Document_id: 54311
From: u9035710@wraith.cs.uow.edu.au (Scott Anthony Barnett)
Subject: Filter Design Software for IBM-PC

Has anyone got an active filter design program that runs on an IBM PC ??

Something that will easily let me specify bandpass filter parameters,
and it will give me the appropriate component values ??

It has to be public domain,  if anyone has one, could you mail it to me.

Thanks in advance,

Scott
u9035710@wraith.cs.uow.edu.au

P.S. It can run under windows if necessary.



Newsgroup: sci.electronics
Document_id: 54312
From: swanee@megadata.mega.oz.au (Geoff Swan)
Subject: Re: Why circuit boards are green?

In article <1993Apr23.102039.1720@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
> 
> The color of the board shows the composition of it, hence the use of it.
> 
> Original and older boards were bakelite composition, and were brown.
> Phenolic (spelling) was a tan
> Most "non filled" fiberglass boards used in computers are green.
> Filled fiberglass is blue.
> Teflon is white.
> 

Rubbish. The reason for the colour of the boards depends on the solder
mask that is used. Older boards (bakelite and phenolic) rarely used
a solder mask (these boards are not suited well to automatic stuffing
and soldering techniques) and hence are the colour of the compound
used to make them. These days boards are made of fibreglass for most
general purpose uses and have a solder mask applied to them to prevent
close traces shorting to one another during soldering (and also to prevent
the decomposition of traces under harsh environments). The light and dark
green boards ofter seen have a "dry film" mask applied to them (usually
applied as a complete film photographically produced). The blue (and red
or orange) boards are a two-part epoxy or a liquid-imageable resist
formulation and are applied in a different manner. There's a lot of info
about the pro's and con's of each, but that's another story...

    Sla/n go fo/ill,
                    Risky B.
--------------------------------------------------------------------------
Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
Megadata Pty Ltd                     /      \ 
2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
NSW 2113, Australia.                       v          (Fax) +61 2 887 4847




Newsgroup: sci.electronics
Document_id: 54313
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Re: PC parallel I (!= I/O)

erickson@azure.nmt.edu (Alan Erickson) writes:

> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?

 
        Yes, it is possible.  I'm making a 7 stepper controller board, 
with 7 digital inputs, and (up to) 18 digital outputs from the // port.
   One main thing that will tell you whether the // port is 
bi-directional or not is the bus tranceiver on it.  Look for a chip 
numbered 74LS245.  If you don't have this, then it's probably a 74LS244, 
which will do you NO good for reading in.
  
          Now, if you do have the '245 then do the following:
  First, find the address of the port, (decimal) either 888, or 632.
  In pascal, you would "Write(Port[xxx]);" where xxx is the address in 
either hex or decimal.  The status lines, pins 14, 16, 17, as well as the 
strobe, pin 1, are bi-directional lines, and are read by base address +2, 
so for 888, to read from status, then read from 890.  You can also output 
to these lines in the same fashion as to the data lines.  In pascal, 
do "Port[xxx]:=value
".
 
                Hope this helps.
        Let me know if you need more help.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
Document_id: 54314
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: ___Fax Machine scanners to mono-computer scanners?

 
        I was wondering, since I've got a few fax machine scanners 
intact, if they could be integrated to the pc environment as a 
mono-scanner?  If so, where to start?!
 
                Thanks.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
Document_id: 54315
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: ^^ Phosphorescent pads ...

 
         A while ago I saw some translucent pads, about 6"x8" or so that 
could be plugged into (something) and they would glow.  One was red, 
another green, another blue.  Interresting.  I was wondering if anyone 
would have a feed on anything of this nature, and of the price.
   oh, the pads were rubber-like and were floppy like, about 1cm thick or 
so.
 
                Thanks.
 
 
  _________________________________________________
  Inspiration  |   ___                             |
  comes to     |  \   o  baden@sys6626.bison.mb.ca |
  those who    | (  ^  ) baden@inqmind.bison.mb.ca |
  seek the     |   /-\      =] Baden de Bari [=    |
  unknown.     |                                   |
  ------------------------------------------------- 
 

Newsgroup: sci.electronics
Document_id: 54316
From: baden@sys6626.bison.mb.ca (baden de bari)
Subject: Wanting 3479P's...

 
        If anyone would have a low quantity distributer for these little 
beasts (3479P) by Motorola, please let me know!
 
_______________________________________________    
             |                                 |
   _______   |    Baden de Bari                |
  /       \  |     baden@sys6626.bison.mb.ca   |
 (| o   o |) |     baden@inqmind.bison.mb.ca   |
  |   ^   |  | >> True life can only           |
  \  -=-  /  | >> be experianced by            |
   \_____/   | >> those who do not fear death. |
-----------------------------------------------


Newsgroup: sci.electronics
Document_id: 54317
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr26.235820.10742@mnemosyne.cs.du.edu> gvolk@nyx.cs.du.edu (Greg Volk) writes:
>What I usually use...and this stuff is only good on glass....is either Acetone,
>or a little Benzene. The latter of the two is a bit dangerous (possibly a 
                                                ^^^^^^^^^^^^^^^  ^^^^^
>carcinogen(sp?)) but it usualy gets the job done. I imagine you can you the two
  ^^^^^^^^
>solvents on most metals as well as glass, but keep the stuff away from plastic.

Benzene is most definitely a carcinogen. If you can get your hands on it

* Don't use it! *

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
Document_id: 54318
From: neilson@pmin28.osf.org (Peter Neilson)
Subject: Re: solvent for duct-tape adhesive?

In article <1993Apr27.030226.16016@uvm.edu> me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko) writes:
>From article <1993Apr27.004240.24401@csi.jpl.nasa.gov>, by eldred@rrunner.jpl.nasa.gov (Dan Eldred):
>> In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>>>I know this is a long shot, but does anyone know what solvent I should 
>>>use to clean duct-tape adhesive from carpet?
>>>Someone taped wires to the carpet, and now it is time to move out.
>>>
>> I don't know for sure that this will work, but you might try MEK (methyl
>> ethyl keytone?).  It worked getting the stickum left over from shelf paper,
>> and is available at paint stores.  Use a carbon gas mask and lots of
>> ventilation--this stuff really stinks!
>> 
>> 	- Dan
>> 
>
>For those who don't know, methyl ethyl ketone is more commonly known 
>as ACETONE and can be found as the major active ingredient in
>NAIL POLISH REMOVER.  YOUR WIFE'S PROBABLY GOT SOME HANGIN' AROUND....

Oh dear, time for me to try to remember my chemistry.  Let's see if I
can find the formulae somewhere in the dim recesses of my mind.
<sounds of gears>  <fumes of overheated oil>  <unmistakable stench of
the Nasal Chromatograph>   Ha!  I knew there was a double bond!  Now
how shall I show that in ASCII? 

          MEK:                                 Acetone:

          C - C - C - C                        C - C - C
              #                                    #
              O                                    O

The hydrogens are not shown, and # represents double bond.  MEK has a
methyl (CH3) on one side, and an ethyl (C2H5) on the other.  Acetone
has two methyls.  So acetone is not methyl ethyl ketone, but instead
is dimethyl ketone.  Both solvents have similar properties.  I think
that MEK may be a little less flammable but a lot worse to breathe.
It's a lot harder to buy MEK than it once was.  Use acetone.

Nail polish remover consists almost entirely of acetone.  If you buy
some for your workshop, get the very cheapest, because the more
expensive kind has oils and perfumes that you don't need.
-- 
Nothing is so foolish that it has not been posted to some net newsgroup.
         >>> Peter Neilson --- neilson@osf.org <<<
Quote changed daily.  If you've seen this one before, burn your calendar.

Newsgroup: sci.electronics
Document_id: 54319
From: ba1926108@ntuvax.ntu.ac.sg (AaronAw)
Subject: Card Phones

Can you help me to understand how a CardPhone operates and 
how the values are stored on the phonecard..

Thanx


Newsgroup: sci.electronics
Document_id: 54320
From: d9bertil@dtek.chalmers.se (Bertil Jonell)
Subject: Re: How universal are phones these days?

In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
>There is a wire without any jack at the end sticking out of the wall. So you
>need to connect the wires (I'm not sure if they have wall jacks in Western
>Europe - they may).

  Son of the Return of the "How much does Americans know about the rest of
the word?"-flamewar anyone?

-bertil-
--
"It can be shown that for any nutty theory, beyond-the-fringe political view or
 strange religion there exists a proponent on the Net. The proof is left as an
 exercise for your kill-file."

Newsgroup: sci.electronics
Document_id: 54321
From: fedup@firga.sun.ac.za (FE DU PLESSIS [M.ING E&E])
Subject: Re: References for ANY IC

 In a previous article, ree88132@zach.fit.edu (Keith Ledig) writes:
>I am looking for a text/reference that will include pinouts, 
>description, and functionality for just about any IC made.
...

You can find cross reference to almost any IC or discrete semiconductor in 
Philips ECG: Semiconductors Master Replacement Guide, ~$10. (Especially 
industrial, commercial and entertainment, but not specialised or military.)

 - Francois

Newsgroup: sci.electronics
Document_id: 54322
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - SunConnect ICNC)
Subject: Re: How universal are phones these days?

In article <C651xu.Gwq@news.chalmers.se>, d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
> In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
> >There is a wire without any jack at the end sticking out of the wall. So you
> >need to connect the wires (I'm not sure if they have wall jacks in Western
> >Europe - they may).
> 
>   Son of the Return of the "How much does Americans know about the rest of
> the word?"-flamewar anyone?


We're doing that one in s.c.british at the moment...





Newsgroup: sci.electronics
Document_id: 54323
From: harris@athena.mit.edu (Jonathan G Harris)
Subject: Re: solvent for duct-tape adhesive?

>>> On benzene and acetone.
Not only is benzene a carcinogen, it is adsorbed through the skin and cause
cumulative damage to the bone marrow which is essential to the production of
your blood cells.  It is highly toxic. One exposure is unlikely to kill you,
but it will likely do hidden damage.  Benzene is one compound that chemists
try like hell to avoid using!
Acetone is much less toxic, but is highly flammable and volatile. 
It also dissolves lots of things so handle with great care!
-- 
Jonathan G. Harris
Department of Chemical Engineering,  MIT Rm 66-450 
25 Ames Street, Cambridge, MA 02139
harris@athena.mit.edu (617)253-5273  Fax 253-9695

Newsgroup: sci.electronics
Document_id: 54324
From: rbhurtha@cs1.uct.ac.za (R BHURTHA)
Subject: HD-TV SOUND SYSTEMS

I would like to get some information on the current systems used for HD-TV
sound systems.thanks.

Newsgroup: sci.electronics
Document_id: 54325
From: jmichael@vnet.IBM.COM
Subject: Re: solvent for duct-tape adhesive

Acetone will likely damage the carpet. First solvent to try is denatured
alcohol. Do not waste your time with rubbing alcohol. You can use methyl
alcohol instead of denatured alcohol. If you want to have a cocktail while
you are removing the goo, use pure grain alcohol :-). If the alcohol does
not work try carbon tetrachloride. If neither of these work you may need to
try a stronger solvent, but the alcohol works for most adhesives. Good luck.

Jim

Newsgroup: sci.electronics
Document_id: 54326
From: lan_kova@rcvie.co.at (Tom Kovar)
Subject: Re: How universal are phones these days?

d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
: In article <1rh22eINNfce@shelley.u.washington.edu> kniha@carson.u.washington.edu (Dagmar Amtmann) writes:
: >There is a wire without any jack at the end sticking out of the wall. So you
: >need to connect the wires (I'm not sure if they have wall jacks in Western
: >Europe - they may).
: 
:   Son of the Return of the "How much does Americans know about the rest of
: the word?"-flamewar anyone?

  Well, Bertil, you might laugh, but in many places here in Austria, there are
no wall jacks yet, either - just wires sticking out of the wall (and put into
a closed, often sealed, box) :-)
  As far as I remember from Germany, it is a nicely mixed situation - somebody
had wires sticking, somebody had jacks...
  On the other hand, everywhere in Bohemia I have seen wall jacks, and never
seen just wires sticking out of the wall... And I thought Slovakia was the
same case. Well...

  "How much do Scandinavians know about the rest of Europe?? :-))"

							Tom
-- 

       ___  /   ___  /   ____/    Tomas Kovar
      /    /   /    /   /         Alcatel Austria Forschungszentrum G.m.b.H.
     ___  /   ___  /   __/        A-1210 Wien, Ruthnergasse 1-7
    /    /   /    /   /           Tel: +431-391621-283 Fax: +431-391452
 __/  __/ __/  __/ __/            E-Mail: Tom.Kovar@rcvie.co.at                               

Newsgroup: sci.electronics
Document_id: 54327
From: pvr@wang.com ()
Subject: Re: 2% silver solder

shiekh@ictp.trieste.it (Andy Shiekh) writes:

>  I have seen the existance of electronics solder with a 2% silver
>content that seems to have good wetting and fatique reatings.
>  Can anyone tell me why it is not used? (silver is not such an expensive
>metal).

   This is called silver bearing solder.   It is used to solder to
devices that have silvered contacts.   One application is soldering
to the ceramic terminal strips used in the old Tektronix scopes.   These
were notched ceramic strips that were silver plated in the notches.
If you used ordinary solder the molten metal would disolve the silver
off of the ceramic.   The silver was quite thin.   The 2% is a saturated
solution of silver in tin and lead.    Thus, no more silver can be
disolved in the solder solution.   Other devices that use silver contacts
are quartz crystals and ultrasonic transducers.
--
-->>>>>>>>>> Peter Reilley ..... pvr@wiis.wang.com ..... KA1LAT <<<<<<<<<<<--
     For info on BEAV (Binary Editor And Viewer) finger pvr@das.wang.com
                     Well, that about says it.

Newsgroup: sci.electronics
Document_id: 54328
From: wwerner@thor.mlb.semi.harris.com (William S. Werner)
Subject: Correction to Harris's AnswerFAX Phone Number

     ====================================================
       H    H      A      RRRRR    RRRRR   IIIII  SSSS
       H    H     A A     R    R   R    R    I   S    
       HHHHHH    AAAAA    RRRRR    RRRRR     I    SSSS
       H    H   A     A   R    R   R    R    I        S 
       H    H  A       A  R     R  R     R IIIII  SSSS  
     ====================================================


Harris Semiconductor now has AnswerFAX. AnswerFAX is on-line 24 hours
a day, 7 days a week, so you can instantly receive datasheets and 
application notes by using your touch-tone telephone and FAX machine.
The number to call is (407) 724-3818. (It is not set up to do international
calls at this time.)

The general decision tree for the AnswerFAX is as follows, the numbers are
the available selections:


       Welcome to Harris Semiconductors AnswerFAX
                           |
        ----------------------------------------
        |                                      |
        1                                      2
        |                                      |
 Select 1 if you                        Select 2 for an
 are familiar with                      explanation of
 AnswerFAX.                             AnswerFAX
        |                                      |
        |--------------------------------------|
                           |
                           |                              
                           |
            --------------------------------
            |                              |
            1                              2
            |                              |
     Select 1 to order              Select 2 for a
     a document (the                list of catalogs:
     document list is                  1  New Products
     in the catalogs,                  2  Linear Products
     get them first)                   3  Data Acquisition Products
            |                          4  Digital Signal Processing Products
            |                          5  Discrete Power and Intelligent
            |                             Power Products
            |                          9  Application Notes
            |                              |
            |                              |
  Select appropriate document    Select Appropriate Catalog
            |                              |
            |                              |
  Do you want to order           Do you want to order
  anything else? If yes,         anything else? If yes,
  you will be taken back         you will be taken back 
  to the selection decision.     to the selection decision.
            |                              |
            |                              |
            --------------------------------
                          |
                          |
                          |
                  What is phone number
                    for your FAX?
                          |
                          |
                  What is your name?
               (request the instructions)
                          |
                          |
                         END                        



Bill Werner


===========================================================================
Bill Werner           WWERNER@hsscam.mis.semi.harris.com
Harris Semiconductor  wwerner@thor.mlb.semi.harris.com
Melbourne Florida     "....life is but a candle, and a 
(407)729-5515         dream will give it flame..." - Rush, Caress of Steel
===========================================================================
 


Newsgroup: sci.electronics
Document_id: 54329
From: iisakkil@beta.hut.fi (Mika Iisakkila)
Subject: Re: How universal are phones these days?

d9bertil@dtek.chalmers.se (Bertil Jonell) writes:
>  Son of the Return of the "How much does Americans know about the rest of
>the word?"-flamewar anyone?

Let's save some bandwidth, skip the intermediate articles and go
straight to the Nazis and Hitler :-)

(we do have wall sockets, thank you, and they're better than yours)
--
Segmented Memory Helps Structure Software

Newsgroup: sci.electronics
Document_id: 54330
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: How to the disks copy protected.

In article <1ra4hrINN3ni@DOLPHIN.ZOO.CS.YALE.EDU> stone-andy@cs.yale.edu (Andy Stone) writes:
>Subject: Re: How to the disks copy protected.
>	I wrote a commercial program called GAME-MAKER (can you guess what
>it does).  What we do is have a document protect (answer Question on page x, 
>line y), which is a real pain.  We also allow the user to register by sending
>in a card, and computing a # based on their name.  The system works in that
>we've gotten lots of registration cards.
>	I hear that the program has been cracked though.  Someone two people 
>actually called up my support--one with a question, the other wanting to
>buy our graphics libraries (right!).  Anyway if anyone wants to help me
>catch a cracker and has the cracked version, mail me.  I won't accuse
>you (unless you're the cracker of course).
>

I know of at least one ftp-site from which you can download the cracks of
about any commercial game in existence. The names of the companies (yes,
companies!) are also blatantly advertised with the crack codes. According to
them, it is not illegal (at least in the USA, according to a statute or 
something) to remove the copy protection from any program. The only condition
is that you may only use this code on legally owned software for your own
convenience.

If there is any interest I will download the advertisement of one such 
company. I will not give the name of this ftp-site to anyone, even if only
to protect the companies which wrote the original games.

DISCLAIMER: I do not condone the use or cracking of any programs. I believe 
it hurts the industry and individuals in the long run.

On the subject of copy protection: Most pirates don't give a damn about 
using software on which the name of the registered owner came up on starting 
the program. They just don't have a conscience.

- gerrit

Newsgroup: sci.electronics
Document_id: 54331
Subject: Re: FM Transmitter ICs- Help!!!!!
From: ganter@ifi.unibas.ch (Robert Ganter)

In article <1993Apr27.080115.22046@vd.seqeb.gov.au>  writes:
> I am trying to design a small 90mW 472MHz FM transmitter for remote alarm
> use.
> 

Pretty high frequency for one chip...

> Is there an FM transmitter IC available that can be used for this purpose?
> 
> Any help, circuits, info etc will be greatfully accepted.
> 
> Please reply to bsc_graham@seqeb.gov.au
> 

Yes and no. I would use the FM transmitter chip from Motorola (Linear and  
Interface Databook), a stable cristal oscillator and a mixer (e.g. SBL-1 from  
mini circuits lab). Everything is done in the FM chip and then mixed up with  
the oscillator frequency. Just have a look at the ARRL Handbook. There are lots  
of ideas in there about oscillators and mixing. I don't think, there are single  
chip designs for such high frequencies yet.

> Thanks in advance.
> 
> Graham Castledine.

Cheers   Robert HB9NBY
--
Robert Ganter			/------------\
Universitaet Basel		| I am a fan |
Institut fuer Informatik	| of my plan |
Basel/Switzerland		\------------/
ganter@ifi.unibas.ch
amateurradio: HB9NBY	packet: HB9NBY@HB9EAS.CHE.EU

Newsgroup: sci.electronics
Document_id: 54332
From: pguello@uwsuper.edu (Paul Guello)
Subject: Re: solvent for duck tape adhesive

If you want to try a non-toxic solvent, there's one made of citrus that 
works very well and doesn't take your skin off in the process.  One brand 
name I've used is Citra-Solve, but there are others too.

Newsgroup: sci.electronics
Document_id: 54333
From: v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER)
Subject: Looking for a good book on Pspice 5.2


	I just got a copy of spice 5.2. I would like to know if there are
any published books on the market yet and where I could get one. I would
appreciate any help. Thank You

		Neil Gandler

Newsgroup: sci.electronics
Document_id: 54334
From: pmanson@bnr.ca (Peter Manson)
Subject: Re: solvent for duct-tape adhesive?

In article <1rh9b0INN2r4@snoopy.cis.ufl.edu> ruck@beach.cis.ufl.edu (John Ruckstuhl) writes:
>I know this is a long shot, but does anyone know what solvent I should 
>use to clean duct-tape adhesive from carpet?

Yet another suggestion, but this one is non-toxic (although I would handle
it like any other cleaner) and it smells nice.  The chemical is called
d-Limonene, and it smells like lemon peels (I think it is a lemon extract
of some kind).  You might find it in a hardware store, sold as a
general-purpose solvent, but your best bet would be any bike store --
it is used as a chain-cleaning fluid.  It works on sticker glue, crayons,
grease, oil, etc.

It's clear yellow in the bottle, and you can use it straight; if you add
water, it changes to a creamy consistency, which is good for some jobs.

Peter

Newsgroup: sci.electronics
Document_id: 54335
From: deaddio@ski.bellcore.com (Michael DeAddio)
Subject: Acceleration sensor?

Does anyone know of any type of acceleration sensor that has
an electrical output of any sort?  It would only have to sense
acceleration in one direction.

Thanx,

Mike

-- 

________________________________________________________
Michael DeAddio (MTS)         | Work hard, play hard, 
Bell Communication Research   | the only problem is that 
deaddio@thumper.bellcore.com  | playing hard makes 
201-829-5024                  | working harder.
MRE 2Q-260                    | 

Newsgroup: sci.electronics
Document_id: 54336
From: inelson@gopher.cc.ucf.edu (Ian Nelson - I&R IBM Consultant)
Subject: Old schematics

Wonder if anyone would know where (or if) I could find the schematic for the 
old Timex-sinclare (sp) computer... Or even a pin out on the expansion bus??

					Thanks in advance..
					Ian Nelson
					(inelson@ucf1vm.cc.ucf.edu)

Newsgroup: sci.electronics
Document_id: 54337
From: mcole@spock (COLE)
Subject: Disk drive read & write

I am working on a project and am in need of information regarding the  
currents (at the head) needed to write to a hard drive and the currents  
produced when reading.  If anyone has information it would be much  
appreciated.
mcole@nmsu.edu

Newsgroup: sci.electronics
Document_id: 54338
From: DPierce@world.std.com (Richard D Pierce)
Subject: Re: Acceleration sensor?

In article <1993Apr27.145201.15495@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.

Gee, how about an (ahem) "accelerometer"! Such devices are available from
a variety of sources (one that comes to mind is Bruel & Kjaer if you have
a lot of money to spend). MOst of these sorts of devices output a voltage
proportional to acceleration. You need to know what range you're talking
about though.


-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |

Newsgroup: sci.electronics
Document_id: 54339
From: wex@cs.ulowell.edu (Paul M. Wexelblat)
Subject: Re: solvent for duct-tape adhesive

In article <19930427.060713.357@almaden.ibm.com>, jmichael@vnet.IBM.COM writes:
|> From: jmichael@vnet.IBM.COM
|> Date: Tue, 27 Apr 93 09:00:18 EDT
|> Subject: Re: solvent for duct-tape adhesive
|> you are removing the goo, use pure grain alcohol :-). If the alcohol does
|> not work try carbon tetrachloride. If neither of these work you may need to
                ^^^^^^^^^^^^^^^^^^^^

DO NOT HEAT THE CCL4 -- IT MAKES PHOSGENE GAS of WW-I poison gas fame

(remember when they used carbon tet in fire extinguishers?)


(yes, I know I was yelling)

-- 

	...Wex

Newsgroup: sci.electronics
Document_id: 54340
From: wb8foz@fmsystm.ncoast.org (David Lesher)
Subject: HP 200CD manual

The 200CD is one of three oscillators that HP made many years ago. 
(The others were the Low Frequency Oscillator and the Wide Range 
Oscillator.) These are the ones with the 7" diameter chrome dial,
a Wein Bridge circuit that used pilot lights as the feedback loop,
and firebottles that produced many volts of output.

I've just acquired a pair of these venerable old beasts. 
The non-working one, SN 605, (owned by Crosley Radio at one point!)
needs help. I know I can likely buy a microfiche copy of the book 
from HP, but that costs.... and considering I paid a dollar for
the pair in the rain at the Dayton Hamvention;-}

Does anyone have such a book they could copy parts of for me?
Thank you....

Newsgroup: sci.electronics
Document_id: 54341
From: zlau@arrl.org (Zack Lau)
Subject: Re: Why circuit boards are green?

In sci.electronics, swanee@megadata.mega.oz.au (Geoff Swan) writes:
>
>Rubbish. The reason for the colour of the boards depends on the solder

The May 1993 cover of QST has a picture of three different boards without
any solder mask (you can tell from the copper colored traces). The box
labeled 2304 transverter has the brown teflon/glass board, while the one
in the center has the grayish board exposed.  On the left is some 
fiberglass board that looks green to me.  I see no reason
for putting solder mask on circuit board used for box covers :-).

I wonder if any manufacturer actually puts a solder mask on their
low noise microwave preamps?  Often, microwave circuits have odd
bits of wire/foil/metal attached to wherever/whatever is necessary
to make the unit work properly (this is a commercial product?).  A
solder mask would certainly make doing this tougher, never mind 
the finding something that minimally degrades the circuits.  (Q dope
for coils *does* not improve the Q--it just holds things together with
minimal loss).

Zack Lau  KH6CP/1

Internet: zlau@arrl.org           "Working" on 24 GHz SSB/CW gear     
			          Operating Interests: 10 GHz CW/SSB/FM
US Mail: c/o ARRL Lab				       80/40/20 CW
	225 Main Street		  Station capability: QRP, 1.8 MHz to 10 GHz
	Newington CT  06111	               modes: CW/SSB/FM/packet
						      amtor/baudot
Phone (if you really have to): 203-666-1541

Zack Lau  KH6CP/1

Internet: zlau@arrl.org           "Working" on 24 GHz SSB/CW gear     
			          Operating Interests: 10 GHz CW/SSB/FM
US Mail: c/o ARRL Lab				       80/40/20 CW
	225 Main Street		  Station capability: QRP, 1.8 MHz to 10 GHz
	Newington CT  06111	               modes: CW/SSB/FM/packet
						      amtor/baudot
Phone (if you really have to): 203-666-1541

>mask that is used. Older boards (bakelite and phenolic) rarely used
>a solder mask (these boards are not suited well to automatic stuffing
>and soldering techniques) and hence are the colour of the compound
>used to make them. These days boards are made of fibreglass for most
>general purpose uses and have a solder mask applied to them to prevent
>close traces shorting to one another during soldering (and also to prevent
>the decomposition of traces under harsh environments). The light and dark
>green boards ofter seen have a "dry film" mask applied to them (usually
>applied as a complete film photographically produced). The blue (and red
>or orange) boards are a two-part epoxy or a liquid-imageable resist
>formulation and are applied in a different manner. There's a lot of info
>about the pro's and con's of each, but that's another story...
>
>    Sla/n go fo/ill,
>                    Risky B.
>--------------------------------------------------------------------------
>Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
>Megadata Pty Ltd                     /      \ 
>2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
>NSW 2113, Australia.                       v          (Fax) +61 2 887 4847
>
>
>
>

Newsgroup: sci.electronics
Document_id: 54342
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: PC parallel I (!= I/O)

From article <1993Apr26.110250.5243@nmt.edu>, by erickson@azure.nmt.edu (Alan Erickson):
> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?
> 
> ------------------------------------------------------------------
> Alan Erickson   erickson@baltic.nmt.edu		
> 
> to all SunRayce '93 competitors: I hope you're getting
> about as much sleep as I am.....
> ------------------------------------------------------------------

I'M WATCHING ONE BEING BUILT RIGHT HERE AT UVM AND THE TEAM IS 
SHAGGIN' IT THESE DAYS.
                                 ME170PJD@UVM.EDU

Newsgroup: sci.electronics
Document_id: 54343
From: me170pjd@emba-news.uvm.edu.UUCP (Peter J Demko)
Subject: Re: PC parallel I (!= I/O)

From article <qekN3B4w165w@sys6626.bison.mb.ca>, by baden@sys6626.bison.mb.ca (baden de bari):
> erickson@azure.nmt.edu (Alan Erickson) writes:
> 
>> 	I'm trying to bring in 8+ bits to a PC, and would like
>> 	to use interrupt-driven routines. Without buying an IO
>> 	board or making a new port, _where_ can I bring in these
>> 	bits? LPT seems to have only a few inputs, but I've heard
>> 	rumours that some LPTs have bidirectional lines. Anybody
>> 	know fer sure? If any bi-d LPTs, which boards have them
>> 	(I'll be running a new 386DX-33)?
> 
>  
>         Yes, it is possible.  I'm making a 7 stepper controller board, 
> with 7 digital inputs, and (up to) 18 digital outputs from the // port.
>    One main thing that will tell you whether the // port is 
> bi-directional or not is the bus tranceiver on it.  Look for a chip 
> numbered 74LS245.  If you don't have this, then it's probably a 74LS244, 
> which will do you NO good for reading in.
>   
>           Now, if you do have the '245 then do the following:
>   First, find the address of the port, (decimal) either 888, or 632.
>   In pascal, you would "Write(Port[xxx]);" where xxx is the address in 
> either hex or decimal.  The status lines, pins 14, 16, 17, as well as the 
> strobe, pin 1, are bi-directional lines, and are read by base address +2, 
> so for 888, to read from status, then read from 890.  You can also output 
> to these lines in the same fashion as to the data lines.  In pascal, 
> do "Port[xxx]:=value
> ".
>  
>                 Hope this helps.
>         Let me know if you need more help.
>  
>  
>   _________________________________________________
>   Inspiration  |   ___                             |
>   comes to     |  \   o  baden@sys6626.bison.mb.ca |
>   those who    | (  ^  ) baden@inqmind.bison.mb.ca |
>   seek the     |   /-\      =] Baden de Bari [=    |
>   unknown.     |                                   |
>   ------------------------------------------------- 
>  

AS IT HAPPENS, YOU'VE HELPED ME QUITE A BIT. I'M CONSIDERING BUILDING
A VERY SIMILAR DEVICE JUST FOR SOMETHING TO DO THIS SUMMER.
THE IDEA IS TO CODE THE 8 OUTPUT BITS INTO MULTIPLE 2-BIT 
CURRENT-AMPLIFIED OUTPUT CHANNELS.  SOFTWARE WILL HANDLE THE WAY THE 
AMPLIFIED OUTPUTS ARE MANIPULATED SO THAT THIS MAGIC BOX CAN HANDLE
MORE APPLICATIONS THAN JUST STEPPER MOTORS.  ALSO LOOKING FOR A ROBOT ARM
(CHEAP) TO ATTACH THIS BOX TO SO I CAN WOW AND IMPRESS MY FRIENDS.
    ANY HINTS?       PETER J DEMKO ME170PJD@UVM.EDU 

Newsgroup: sci.electronics
Document_id: 54344
From: josephc@cco.caltech.edu (Joseph Chiu)
Subject: Re: ^^ Phosphorescent pads ...

baden@sys6626.bison.mb.ca (baden de bari) writes:

> 
>         A while ago I saw some translucent pads, about 6"x8" or so that 
>could be plugged into (something) and they would glow.  One was red, 
>another green, another blue.  Interresting.  I was wondering if anyone 
>would have a feed on anything of this nature, and of the price.
>   oh, the pads were rubber-like and were floppy like, about 1cm thick or 
>so.

The curiosities that you speak of are EL (Electro-Luminescent) pads.  They
are mostly used as backlights for LCD's, and as you pointed out, comes
in several different colors.  Many of them emit white-ish colors ("true"
white, and blue-whiteis-blue are the ones that I've personally encountered
the most often.)

They vary in their input requirements, however, they tend to operate at 
about 100 Vrms, and at much higher than 60 Hz.  (400 Hz to 1 kHz, if I 
recall correctly.)   You can get them to work at 120 Vrms, 60 Hz (i.e.,
line) but they don't glow as brightly, and they will degrade much faster.
(Oh yes, almost forgot, EL's have this tendency to wear out over time...)

-- 
Joseph Chiu        | josephc@cco.caltech.edu  "OS/2: You gotta get this thing!" 
MSC 380 - Caltech  |        
Pasadena, CA 91126 | Dear IBM: Hire bunch of technically incompetent people
+1 818 449 5457    | (like my brother) to test OS/2 installation procedures.

Newsgroup: sci.electronics
Document_id: 54345
From: mpaul@unl.edu (marxhausen paul)
Subject: Pressure Zone Microphones

I remember, back before commercial mikes with the "PZM" label (for
Pressure Zone Microphone) started showing up, I read an article,
in some engineering journal, that described the principles involved.
All the physics aside, from a practicle standpoint the author's said
they built a prototype with nothing more than a small Sony lavelier
mike laid up against a large aluminum disk.  In demonstrating it at
a presentation to audio engineers, this was impressive enough that
the people present were bugging them about where they could buy them.

Anyway...I want to build some to use as "choir mikes" (wide coverage).
I've had good luck using some small electret mike elements I got
from Digi-Key - most of these are limited-bandwidth, peakey units
but for a buck or two more I got the ones spec'd to go out to 20kHz
with a bit flatter response.  

The distance of the mike opening from the flat plate is kind of
critical.  I'm debating whether to mount it on it's side, which
puts the opening a shade under 2mm from the plate, or mounting
it with the opening actually pointing down into the plate at a
small clearance.  I haven't dissected a unit like you can buy at
Radio Shack to see how they do it.  Thoughts?


--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
Document_id: 54346
From: jeffj@cbnewsm.cb.att.com (jeffrey.n.jones)
Subject: SPICE for XT with no co-processer?

I want to run SPICE on my XT so I can learn more about amplifiers
and oscilators. Is there a version of this that will run on my XT
with no math co-processer, if so where can I get it? Thanks for any
and all help!

Jeff
-- 
 Jeff Jones  AB6MB         |  OPPOSE THE NORTH AMERICAN FREE TRADE AGREEMENT!
 jeffj@seeker.mystic.com   |  Canada/USA Free Trade cost Canada 400,000 jobs. 
 Infolinc BBS 415-778-5929 |  Want to guess how many we'll lose to Mexico?

Newsgroup: sci.electronics
Document_id: 54347
From: tgk@cs.toronto.edu (Todd Kelley)
Subject: Re: PC parallel I (!= I/O)

erickson@azure.nmt.edu (Alan Erickson) writes:

> 	I'm trying to bring in 8+ bits to a PC, and would like
> 	to use interrupt-driven routines. Without buying an IO
> 	board or making a new port, _where_ can I bring in these
> 	bits? LPT seems to have only a few inputs, but I've heard
> 	rumours that some LPTs have bidirectional lines. Anybody
> 	know fer sure? If any bi-d LPTs, which boards have them
> 	(I'll be running a new 386DX-33)?

I know for sure that the Everex Magic I/O EV-170A can be jumpered
for a printer mode, or for a general purpose bidirectional I/O mode.

Also, I know for sure that the IBM Technical Reference says the following
about the Monochrome Display & Printer Adapter and the IBM Parallel Printer
Adapter:

    It is essential that the external device not try to pull these
    lines [referring to the data lines] to ground.

And later:

    If an external device should be driving data on these pins (in
    violation of usage ground rules) at the time of an input, this
    data will be `or'ed with the latch contents.

I will accept no responsibility if you incur damages of any kind
as a result of my saying, ``I DO NOT know for sure, but I think
you should be able to use a traditional parallel port as an input
port by writing 0x to the data lines, and then reading from the
data lines, while an external device drives them.''  The input
data will not be latched, so noise could make this infeasible.

Todd



Newsgroup: sci.electronics
Document_id: 54348
From: wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus)
Subject: Re: Why circuit boards are green?

In article <1993Apr27.051830.14545@mega.com.au>, swanee@megadata.mega.oz.au (Geoff Swan) writes:
> In article <1993Apr23.102039.1720@mala.bc.ca>, wagner@mala.bc.ca (TOM WAGNER, Wizzard of old Audio/Visual Equipment........Nanaimo Campus) writes:
>> 
>> The color of the board shows the composition of it, hence the use of it.
>> 
>> Original and older boards were bakelite composition, and were brown.
>> Phenolic (spelling) was a tan
>> Most "non filled" fiberglass boards used in computers are green.
>> Filled fiberglass is blue.
>> Teflon is white.
>> 
> 
> Rubbish. The reason for the colour of the boards depends on the solder
> mask that is used. Older boards (bakelite and phenolic) rarely used
> a solder mask (these boards are not suited well to automatic stuffing
> and soldering techniques) and hence are the colour of the compound
> used to make them. These days boards are made of fibreglass for most
> general purpose uses and have a solder mask applied to them to prevent
> close traces shorting to one another during soldering (and also to prevent
> the decomposition of traces under harsh environments). The light and dark
> green boards ofter seen have a "dry film" mask applied to them (usually
> applied as a complete film photographically produced). The blue (and red
> or orange) boards are a two-part epoxy or a liquid-imageable resist
> formulation and are applied in a different manner. There's a lot of info
> about the pro's and con's of each, but that's another story...
> 
>     Sla/n go fo/ill,
>                     Risky B.
> --------------------------------------------------------------------------
> Geoff Swan (research & development)   _--_|\         swanee@mega.com.au
> Megadata Pty Ltd                     /      \ 
> 2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
> NSW 2113, Australia.                       v          (Fax) +61 2 887 4847
> 
> 


Sorry Geoff,

Agree solder mask is green, but in the old days we didn't have wave soldering
machines (which are another topic again).  I had a crew of a dozen ladies which
could stuff and hand solder a board like lightning!

Board under the mask was the original query.

BTW cheap inport electronic devices (mainly from 3rd world countries) are done
with brown pheonolic boards.  Is seems the electronics industry has discovered
the cheap labor pools.  Workers are paid by the board to assemble circuits at
home.  They are very obviously hand soldered.  Quite a few tape recorders are
being brought into Canada from Red China.  In China there is no warranty for
the equipment other than if you plug it in and it works it's yours.  One of my
co-workers spent a year there and he said the failure rate out of the box was
almost 50%.

Also, the original method for making printed with conductive ink on a regular
printing press.  An old lithographer friend had a press for this.  After the
etching method was developed he used the press to print wood grain on doors.
> 
-- 
73, Tom
================================================================================
Tom Wagner, Audio Visual Technician.  Malaspina College Nanaimo British Columbia
(604)753-3245, Loc 2230  Fax:755-8742  Callsign:VE7GDA Weapon:.45 Kentucky Rifle
Snail mail to:  Site Q4, C2.   RR#4, Nanaimo, British Columbia, Canada, V9R 5X9  

I do not recyle.....   I keep everything!       (All standard disclaimers apply)
================================================================================

Newsgroup: sci.electronics
Document_id: 54349
From: ferry@dutentb.et.tudelft.nl (Ferry Toth)
Subject: **** And now serious: E-Magazine *****


For some time I've been thinking about the possiblity of starting a group
where scientific articles can be published (or perhaps just summaries).
Possible advantages would be:
* Free disribution
* Fast acceptance
* Online discussion between authers and readers

This would be possible with one group with a moderator for publishing the
articles and one perhaps without for discussion.

The best thing would be if all the articles would be in a standard format which
would make it possible to print or view the documents camera ready. Perhaps
Postscript or Rich Text Format?

But how do you start a new group? Anyone interrested?

Greeting from Ferrie
Electronics Research Laboratory
Delft University of Technology
Delft
Holland

Newsgroup: sci.electronics
Document_id: 54350
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: cleaning electronic equipment?

In article <adrian.735624685@tasman> adrian@tasman.cc.utas.edu.au (Adrian Lewis) writes:
>	Just a quick question.  What standard lab solvents can be used to
>clean electronic equipment and components safely (ie not corrode, dissolve,
>short-out, etc the equipment)?
>	water?	:-)
>	methanol?
>	CCl4?

You don't say what kind of "electronic equipment" you mean.  It's hard
to give a generic answer.  There is essentially no solvent that won't
do things like washing lubricant out of switches.

When we've needed to do an emergency cleaning job on things, we've just
used distilled water.  The key thing to remember is to make sure the gear
is *completely* dry before powering it up again.  We let it dry for
several days to be damn sure.

I doubt that methanol has significant advantages over water.  I would
be very wary of CCl4, not least because it is dangerous to *you* even
if it's not going to harm the equipment -- not only is it poisonous,
but I believe it's now known to be carcinogenic.
-- 
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  henry@zoo.toronto.edu  utzoo!henry

Newsgroup: sci.electronics
Document_id: 54351
From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: Acceleration sensor?

In article <1993Apr27.145201.15495@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.
>Thanx, Mike
>Michael DeAddio (MTS)         | Work hard, play hard, 
>Bell Communication Research   | the only problem is that 
>deaddio@thumper.bellcore.com  | playing hard makes 
>201-829-5024                  | working harder.
>MRE 2Q-260                    | 

SETRA SYSTEMS, 4 Nagog Park, Acton, MA 01720, Ph: (617) 263 - 1400
Schaevitz Engineering,  US Rt. 130 & Union Ave., Pennsauken, NJ 08110
     Ph: (710) 892 - 0714

Accelerometers are not cheap, mainly because the outputs are fairly linear 
with respect to acceleration.  You don't say what the range of acceleration 
you want to measure is, and there are other ways in which to measure it 
other than using an accelerometer.  Additional information would be helpful 
to anyone who may respond.

Call, if you wish.

Newsgroup: sci.electronics
Document_id: 54352
From: nagle@netcom.com (John Nagle)
Subject: Re: Why circuit boards are green?

ulan@ee.ualberta.ca (Dale Ulan) writes:
>kuusama@kaarne.cs.tut.fi (Kuusama Juha,,,VTT,) writes:
>>Not that the question is anything important, but I am still curious:
>>Why is that almost all printed circuit boards are green? I have seen
>>a few blue ones, but no red, yellow, company logo etc. Is there a
>>technical reason or could it be that the marketing "geniuses" have
>>not tought about it (yet)?

       It's possible to make boards in other colors, and I have an ad
for laser light-show equipment which offers the circuit boards in your
choice of Day-Glo (tm) colors.

       The usual light green color is just the natural color of Fiberglas.
The dark green or blue is the solder mask layer, and I suspect that color
is a dye.  

						John Nagle

Newsgroup: sci.electronics
Document_id: 54353
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Pressure Zone Microphones

In article <1rjobdINNk1s@crcnis1.unl.edu> mpaul@unl.edu (marxhausen paul) writes:
>I remember, back before commercial mikes with the "PZM" label (for
>Pressure Zone Microphone) started showing up, I read an article,
>in some engineering journal, that described the principles involved.
>All the physics aside, from a practicle standpoint the author's said
>they built a prototype with nothing more than a small Sony lavelier
>mike laid up against a large aluminum disk.  In demonstrating it at
>a presentation to audio engineers, this was impressive enough that
>the people present were bugging them about where they could buy them.

Yup, it's not all that difficult to do.

>Anyway...I want to build some to use as "choir mikes" (wide coverage).
>I've had good luck using some small electret mike elements I got
>from Digi-Key - most of these are limited-bandwidth, peakey units
>but for a buck or two more I got the ones spec'd to go out to 20kHz
>with a bit flatter response.  

The Panasonic cartridges aren't bad, but they aren't spectacular.

>The distance of the mike opening from the flat plate is kind of
>critical.  I'm debating whether to mount it on it's side, which
>puts the opening a shade under 2mm from the plate, or mounting
>it with the opening actually pointing down into the plate at a
>small clearance.  I haven't dissected a unit like you can buy at
>Radio Shack to see how they do it.  Thoughts?

Don't mount it on the side.  Call up Crown, the company that has the
patent on the PZM, and ask them for information on construction and
use of the things.  You may have to determine the correct spacing
emperically with a noise source and a spectrum analyzer because the
design of the Panasonic cartridges uses a tuned cavity in front of
the electret element to increase the high frequency response, and you
are going to be altering the resistance through the cavity entrance.

Crown has a nice book on the subject, though it's unfortunately rather
short on mathematics.  There's a JAES article from many years back, too.

Still, for your application, you'll be a lot better off buying the cheap
Radio Shack models and using Phil Rastoczny's modifications to get a
clean balanced output.  Phil's mods seem to get reposted here on a regular
basis.
--scott

Newsgroup: sci.electronics
Document_id: 54473
From: nds@dcs.ed.ac.uk (Neil D Stevenson)
Subject: Re: Picking up cable tv with an aerial.

In article <1993Apr27.202305.4363@mav.com>, toddi@mav.com (Todd Inch) writes:
> In article <1993Apr16.003132.1@wcsub.ctstateu.edu>
> ritterbus001@wcsub.ctstateu.edu writes:
> 
> Regarding pointing an antenna at a "leaky" CATV cable:
> 
> >Wow, what a concept!  Does anybody want to speculate on how this
> >"non-connection" would fit into the theft of cable services laws?
> >It seems to me that unless this case is specifically written into
> >the legislation that the cable company would not have a leg to
> >stand upon in court.
> 
> Well, the CATV company, in the US, is accountable to the FCC for how
> much transmission their cables make.  In fact, I've heard first hand
> about how the CATV company asked to inspect the wiring in a
> home/business to find the source of RF leaks.  I've heard many of their
> vans have RF detectors and they keep one eye on them as they drive down
> the street.
> 
> If the cable is leaky enough to have usable signal, I would GUESS that
> they're probably in violation of FCC transmission laws.
> 
> In England they do (did?) require permits to OPERATE A TV!!!
> Supposedly, the "TV police" drove around with RF detectors looking for
> the IF or whatever produced by a receiver that wasn't registered.  I'm
> guessing the purpose was just something else they could get away with
> taxing.  I don't know if the "TV police were/are just urban legend or
> an actuality.

The TV Police are still with us I'm afraid. A 1000 pound fine goes out to
the unlicensed users(if caught).

Newsgroup: sci.electronics
Document_id: 54474
From: csulo@csv.warwick.ac.uk (Mr M J Brown)
Subject: Re: Picking up cable tv with an aerial.

In article <1993Apr27.202305.4363@mav.com> toddi@mav.com (Todd Inch) writes:
>
>In England they do (did?) require permits to OPERATE A TV!!!
>Supposedly, the "TV police" drove around with RF detectors looking for
>the IF or whatever produced by a receiver that wasn't registered.  I'm
>guessing the purpose was just something else they could get away with
>taxing.  I don't know if the "TV police were/are just urban legend or
>an actuality.

They are real, and we still pay licence fees to receive TV.
The detector vans pick up the IF, true. This tells them what channel you
are watching. The can also pick up the line time base freq, and frame rate
(Try it with a LW/MW radio near telly, it picks up a sharp hum)

From this they can even watch (poor quality though) what *you* have on the
screen, by picking up re radiating junk.

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |    csulo@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |
=============================================================================
              Lost interest ?? It's so bad I've lost apathy!
=============================================================================



Newsgroup: sci.electronics
Document_id: 54477
From: jhwhit01@ulkyvx.louisville.edu
Subject: Re: Microcontroller Questions for newcomer

Does anyone have recommendations on whether a smart data I/O (print spooler,
digital sampling, etc.) would be better implemented with a DMA chip or a
dedicated microcontroller?  Essentially what I am trying to decide is the best
way to handle moving data from a port with automatic handshaking from or to a
memory area that will be accessible by a main system processor when not in use
by the smart data I/O.
 
Which DMA or microcontroller chip would be best to use?  Fast, cheap, and easy
to obtain would be nice, but I won't limit my choices to only those that fit
those characteristics.  Even an 8086/8088 (under $5) would do what I want,
but I am sure there is a better alternative -- like a microcontroller with
onchip (E)EPROM.
 
So I essentially want to hear about all DMA and microcontrollers that are simple
to interface and will move data from one place to another while monitoring a
few I/O lines.
 
Jeff White          jhwhit01@ulkyvx.louisville.edu

Newsgroup: sci.electronics
Document_id: 54478
From: wout@dutentb.et.tudelft.nl (Wout Serdijn)
Subject: Re: **** And now serious: E-Magazine *****

Ferry Toth writes:

>For some time I've been thinking about the possiblity of starting a group
>where scientific articles can be published (or perhaps just summaries).
>Possible advantages would be:
>* Free disribution
>* Fast acceptance
>* Online discussion between authers and readers

>This would be possible with one group with a moderator for publishing the
>articles and one perhaps without for discussion.

>The best thing would be if all the articles would be in a standard format which
>would make it possible to print or view the documents camera ready. Perhaps
>Postscript or Rich Text Format?

>But how do you start a new group? Anyone interrested?

>Greeting from Ferrie
>Electronics Research Laboratory
>Delft University of Technology
>Delft
>Holland

Yep! Sounds good to me. suggestion: sci.electronics.art ?

Best regards,

Wouter


Newsgroup: sci.electronics
Document_id: 54479
From: srl@terminus.ericsson.se (Steve Langstaff)
Subject: Re: How universal are phones these days?

In article 1rjq8hINN8je@dns1.NMSU.Edu, rpeter@nmsu.edu (Peter Herman x5495) writes:
:>In <LHE.93Apr26131014@yang.sics.se> lhe@sics.se (Lars-Henrik Eriksson) writes:
:>
:> I would not be suprised if the equipment is compatible, in fact New York
:>Telephone (NYNEX) spend a lot of money on Swedish switching equipment
:>recently.
:>
:>>Lars-Henrik Eriksson                            Internet: lhe@sics.se
:>
:> You can guess what brand of equipment I refer to :-)
:>
:	Lars-Henrik will be pleased to know that his name is
:plastered all over phones at New Mexico State University as well.
:They got the contract when NMSU went to a digital phone system.
[snip]

Not quite correct! The company name is Ericsson. (With a 'c').


---

Steve L.


Newsgroup: sci.electronics
Document_id: 54480
From: srl@terminus.ericsson.se (Steve Langstaff)
Subject: Re: solvent for duct-tape adhesive?

In article 6746@mprgate.mpr.ca, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:

:Lighter fluid is butane.  It's absolutely non-toxic but is an extreme fire
         ^^^^^    ^^^^^^        ^^^^^^^^^^^^^^^^^^^^
:hazard.  You definately don't want to go splashing this stuff around.
:(Use a little on an old rag.)

Butane : "A colourless flammable gaseous alkane..."

Non-toxic? It has some effects when you inhale, allegedly, which can't all be down
to asphyxia (IMHO).




---

Steve L.


Newsgroup: sci.electronics
Document_id: 54481
From: szh@zcon.com (Syed Zaeem Hosain)
Subject: Re: Acceleration sensor?


In article 15495@walter.bellcore.com,  deaddio@ski.bellcore.com (Michael DeAddio) writes:
>Does anyone know of any type of acceleration sensor that has
>an electrical output of any sort?  It would only have to sense
>acceleration in one direction.
>
>Thanx,
>
>Mike

I am not sure about this, but I believe that Analog Devices in Norwood,
MA makes a relatively inexpensive acceleration sensor (primarily for
use in auto air-bag systems). I do not know specs or anything else, but
you might give them a call to find out more info.

								Z


-- 
-------------------------------------------------------------------------
| Syed Zaeem Hosain          P. O. Box 610097            (408) 441-7021 |
| Z Consulting Group        San Jose, CA 95161             szh@zcon.com |
-------------------------------------------------------------------------

Newsgroup: sci.electronics
Document_id: 54482
From: ftqz@aurora.alaska.edu
Subject: Re: CAD Program for Electronics?

In article <1r73vqINNftu@zephyr.grace.cri.nz>, srgxnbs@grace.cri.nz writes:
>>>What I want the CAD program to do is to draw diagrams by
>>>dragging elements onto the screen, and in this the elements
>>>needed are as diverse as vacuum tubes to ICs (case with pins).
> ..
> try DraftChoice, its not windows but its shareware and object
> oriented. Use it with PrintGL for high quality output.
> 
> Bruce
> 
> 
Look for Spice or PSpice

Newsgroup: sci.electronics
Document_id: 54483
From: ftqz@aurora.alaska.edu
Subject: Re: Looking for a good book on Pspice 5.2

In article <C65EGz.BG1@acsu.buffalo.edu>, v064mb9k@ubvmsb.cc.buffalo.edu (NEIL B. GANDLER) writes:
> 	I just got a copy of spice 5.2. I would like to know if there are
> any published books on the market yet and where I could get one. I would
> appreciate any help. Thank You
> 
> 		Neil Gandler
> 
ISBN 0-13-747270-6

Newsgroup: sci.electronics
Document_id: 54484
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Long distance IR detection

jvannes@vms.macc.wisc.edu writes:....
> >I designed and built hardware in 1988 that would output a logic level (from
> >a 567 tone detector) upon detecting a 500 microwatt LED 28 feet away.
> >Used a Motorola MRD360, biased linearly  in a DC-feedback loop to servo out
> >variations in sunlight (and 60Hz from lights). Used no lenses.
> >Allen Sullivan
> I would be interested in knowing more about the sensing hardware.  What did
> you use for the detector?  Could you detect the angle of location, or did
> the system simply respond to the presence of the transmitter in the sensors
> field of view?
 
Phototransistor-> X100 -> X100 -> NE567
with 330Kohm              Limiter 
feedback to base                  
to control operating point (I expect this really hurts Noise Figure! Any
comments from Phototransistor experts?)

We intended to use this atop a stepper motor, to provide headings to the
beacons. The plan was to have 3 or 4 beacons, of different frequencies, in 
each room, and tell the 567 what frequency to phase-lock to. We did not do so.
One challenge was that the available stepper had 8 degree steps!
Knowing the headings to each beacon, we would have used the surveyor 
technique of RESECTION to determine robot location. (No, I ain't going to
explain resection over the net.)

Given hindsight, I would digitize the amplified output of the self-nulling
phototransistor circuit, and correlate in-phase & quadrature square-waves at
the several expected frequencies, to extract AMPLITUDE of each beacon.
By doing this at the numerous steps, even with  8 degree steps, with knowledge
of the angular response of the phototransistor, you SHOULD be able to
rather more accurately determine the heading to each beacon.
Allen Sullivan



Newsgroup: sci.electronics
Document_id: 54485
From: Thomas.Tornblom@Nexus.Comm.SE (Thomas Tornblom)
Subject: Re: How universal are phones these days?

In article <WD.93Apr26122020@sam.cs.tu-berlin.de> wd@cs.tu-berlin.de (Wolfgang Diestelkamp) writes:

   In article <1rg36hINNsr6@darkstar.UCSC.EDU> hugo@cats.ucsc.edu (Hugo Calendar) writes:

   > I'm wondering if I can tote my American touch tone phone around with me
   > to Sweden and Germany.  It's DC powered, and I can buy a special adapter
   > for that in Europe.  The question is if the general electronics work
   > the same.  I can buy a different wall plug and refit it (I'm sure I'd
   > have to), but would that do the trick?

   Two things to watch for:
   In Germany (and I think the same holds for Sweden) only some
   of the connections can handle tone dialing, so make sure the
   phone can be set to pulse dialing.
   In Sweden, the '0' is the first digit and all other digits
   are pushed "down" by one position; this makes dialing (and
   in the process converting numbers) an interesting task.
   Otherwise, it is technically no problem to connect a foreign
   phone to either the German or Swedish phone system.
   OTOH neither you nor I would ever try that, as it is of course
   illegal.

As the phone uses DTMF dialing, which by some magic all telecom
operators seems to have agreed on, this is a complete non-issue.

I don't think there are any switches in Sweden that can't handle DTMF
dialing. Most switches are now digital and thoses that aren't have
been retrofitted with "magic fingers" that converts from DTMF to pulse
dialing.

Thomas
--
Real life:      Thomas Trnblom           Email:  Thomas.Tornblom@Nexus.Comm.SE
Snail mail:     Communicator Nexus AB     Phone:  +46 18 171814
                Box 857                   Fax:    +46 18 696516
                S - 751 08 Uppsala, Sweden

Newsgroup: sci.electronics
Document_id: 54486
From: wd@cs.tu-berlin.de (Wolfgang Diestelkamp)
Subject: Re: How universal are phones these days?

In article <26APR199315293014@utkvx.utk.edu> iturriag@utkvx.utk.edu (Mr. Y) writes:

> I am not quite so sure about the illegality of using a regular American phone
> on your home system. I vaguely remember a few years ago, when "Deutsche
> Bundespost" split into Postdienst, Postbank, and Telekom there was some
> discussion about a new regulation. I know that cordless or cellular phones
> still have to be approved by the Telekom, but does that hold true for regular
> phones? In my areacode in Germany (2234 - Frechen, near Koeln) you can use

Yes, it does.
All the equipment has to have that Telekom approval number to be
legal.
What has changed is that you can buy the equipment somewhere else.
I'm pretty sure the same holds true in Sweden (at least when I read
some information on it about tweo years ago).
And BTW I do know that most of the lines in Sweden can handle tone-dialing,
just don't be sure that all can.

-- 
Wolfgang Diestelkamp
wd@cs.tu-berlin.de
wolfgang@first.gmd.de


Newsgroup: sci.electronics
Document_id: 54487
From: kurtg@drycas.club.cc.cmu.edu
Subject: Re: Ultrasonic pest repellers: Stories, advice, bunk, etc.?

In article <babb-280493102418@larc.sdsu.edu>, babb@sciences.sdsu.edu (J. Babb) writes:
> RE: Ultrasonic pest repelling devices. The ones I've seen use piezoelectric
> transducers driven by a 35-85 KHz swept oscillator. Is there evidence that
> insects are actually repelled by these devices? Can anybody cite gov't
> pubs, or independent lab studies?
> 
> I saw another device that supposedly repels pests by "altering the
> electro-magnetic field of your house wiring". I suppose they capacitively
> couple a hi freq signal to the AC wiring. And this is supposed to repel
> pests???? How? By magnestriction of the wiring? I DONT THINK SO. 
> 

I've been wondering about this myself.  The house wiring thing is really
hokey.  There is no doubt that high pressure ultrasound is annoying, but to
whom?  Given that these devices have been advertised to be effective against
everything from insects to rodents to nasty dogs, what is to say that my
insect repeller won't just annnoy my dog and give me headaches?  Could there
be that much selectivity in frequencies?  Have there been ANY studies
on the effects of various pressure levels, bands, and sweep patterns on
various life forms?

And how effective could they be?  I certainly would not want to tell anyone
that they are safe from nasty dogs because they were carrying a piezoelectric
buzzer...

> 
> Jeff Babb
> babb@sciences.sdsu.edu   babb@ucssun1.sdsu.edu
> Programmer, SDSU - LARC
-- 
Kurt A. Geisel                        SNAIL : 7 Quaker Rd.
White Pine Software, Inc.                     Nashua, NH 03063
ARPA2 : kurtg@drycas.club.cc.cmu.edu  BIX   : kgeisel
GENIE : K.GEISEL                      AIR   : N3JTW
"I will not be pushed, filed, indexed, stamped, briefed, debriefed, or
numbered!" - The Prisoner

Newsgroup: sci.electronics
Document_id: 54488
From: bnguyen@airmics.gatech.edu (Binh Nguyen)
Subject: Re: solvent for duct-tape adhesive?


Another alternative is to cover the adhesive with another piece of
duct tape then remove the tape. 

If it still doesn't work, try WD-40.
BQN


In article <C67stK.FoK@athena.cs.uga.edu>, mcovingt@aisun3.ai.uga.edu
(Michael Covington) writes:
|> In article <stephens.736002130@ngis> stephens@geod.emr.ca (Dave
Stephenson) writes:
|> >mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
|> >>>>
|> >>>I don't know for sure that this will work, but you might try MEK
(methyl
|> >>>ethyl keytone?).  It worked getting the stickum left over from
shelf paper,
|> [etc.]
|> >If you use MEK for your sake wear safty glasses or better still
|> >industrial goggles. The small est drop in the eye will casue  
[etc.]
|> 
|> Please watch those attributions.  It was NOT ME that advocated using
MEK.
|> 
|> -- 
|> :-  Michael A. Covington, Associate Research Scientist        :   
*****
|> :-  Artificial Intelligence Programs      mcovingt@ai.uga.edu : 
*********
|> :-  The University of Georgia              phone 706 542-0358 :   * 
*  *
|> :-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  **
*** **  <><

Newsgroup: sci.electronics
Document_id: 54489
From: mpaul@unl.edu (marxhausen paul)
Subject: Re: Passive Mixer

shaffer-wendy@yale.edu (Wendy Shaffer) writes:

>I'm trying to build a mixer for a friend of mine to run several things into
>a single boom box.  I have a circuit that uses an op-amp powered by either a
>couple of 9V batteries or using some kind of power supply.  But in a catalog
>I was looking at recently, a "passive mixer" for guitar was advertised taht
>doesn't appear to use any power at all.  Does anyone know what the circuit for
>this would be, because then I could just adapt it for RCA jacks, and save my
>friend and I alot of messing with batteries and plugs.  Thanks.

Well, the fastest, crudest mixer (aside from just physically connecting
all your inputs together directly) is to run each signal through a 
resistor to a common output.  The resistors give some isolation so the
signal sources aren't driving directly into each other. 

Taking a wild, seat-of-the-pants guess, I'd say that if you are mixing
high-impedance sources like some dynamic mikes, electric guitar pickups,
etc., your resistors ought to be maybe 5K - 10K or so.  If you are mixing
line-level stuff or the outputs of a Walkman, or such, I'd go with 1K.

input 1 --/\/\/\/ -------------+--- output
                               |
input 2 --/\/\/\/\-------------+
                               |
input 3 --/\/\/\/\-------------+


--
paul marxhausen .... ....... ............. ............ ............ .......... 
 .. . .  . . . university of nebraska - lincoln .  . . .. . .  .. . . . . . . .
 .     .    .  .   .     .   .  .    .   .  .   .    .   .  grace .   .    .  . 
   .         .       .      .        .        .      .        .   happens .     

Newsgroup: sci.electronics
Document_id: 54490
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead ACid Batteries Part 2!!!

In article <1993Apr27.211036.1@ulkyvx.louisville.edu> jhwhit01@ulkyvx.louisville.edu writes:
>In article <1993Apr26.221422.17208@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>
<lots of stuff deleted>

>The lead-acid secondary cell discharge reaction is EXOTHERMIC.  I am glad
>you do not dispute this point.  If you don't want the lead storage battery
>to discharge, it should be stored such that its charged state is the
>equilibrium state.  During winter, the ground, be it covered with
>concrete, dirt, or wood, maintains a cooler temperature on average than
>the surrounding air or the battery.  The heat capacity of air is less than
>that of concrete, dirt, or wood, so it heats faster.  Conversely, air cools
>faster, too.
>
>The normal storage procedure for a battery is to leave it in an unheated
>garage or basement.  The storage surface is often cooler than the
>surrounding air, with the battery temperature somewhere in-between.  E.g.,
>the basement air temperature may be 70 F, the floor temperature 65 F, and
>the battery temperature 66 F.
>
>The air temperature is HIGHER than the battery temperature.  The heat of
>reaction is not going to move up the gradient.  The floor temperature is
>LOWER than the battery temperature, and heat is going to move to it.  The
>floor is an incredible heat sink.
>

Might depend on where you live .. I know locally, for most of the winter
the ground, and concrete floor, within sheds and garages (unheated) is
signifacantly warmer than the average air temperature.  The air does get
warmer during the day, but during the night, the ground and concrete
is definitely warmer, especially when protected by the walls from the
albedo effect.  And the nights are longer by several hours than the
days.

<rest of quoted text deleted>
>
>Jeff White       jhwhit01@ulkyvx.louisville.edu

Richard Dell

Newsgroup: sci.electronics
Document_id: 54491
From: reynhout@cs.uri.edu (Andrew Reynhout)
Subject: Re: Microcontroller Questions for newcomer

acooney@netcom.com (Alan Cooney) writes:
>...discussion of Motorola vs Intel uC's
>
>In other words, just add your favorite serial level converters (Mac folks
>can use the cheaper, farther, and faster RS422 drivers, PC users get to
>suffer with RS232...) and start using your project!  Think about it...

   How much software is out there for the Mac?  I've been interested
in using microcontrollers in imbedded applications for a long time,
but was always under the impression that I would need an IBM to run
the debug/compile/etc software.
   I would like to use a 6811 or 6816.  I'm proficient in 6800 assembly,
but have never NEEDED it except some toying with old 6802EVBs.

   Motorola doesn't seem to have any information on Mac software (at
least their local distributor doesn't) and the ELE department around
here has been of little help as well.
   I hope someone can tell me that I don't have to buy an IBM to 
work with the 6811 or 6816 Evaluation Boards...please send me mail!

   Andrew
-- 
   Andrew <reynhout@cs.uri.edu>    "If you remind me of my dog,
                                    we'll probably get along"  -jane siberry
   meow

Newsgroup: sci.electronics
Document_id: 54492
From: tony@morgan.demon.co.uk (Tony Kidson)
Subject: Re: How universal are phones these days? 

In article <1993Apr27.010612.17126@chpc.utexas.edu> michael@chpc.utexas.edu writes:

>
>Does this imply the German tone dialing is compatible with the American
>one?  I know at least the British system is not -- it is supposedly close
>enough though that an American phone will work.  But my modem (American)
>has a special setting for British standards...
>

Bzzzzzt! Wrong answer.  The UK tone dialling is identical to the US system. 
The different settings on your modem are so that it uses CCITT V21 & V22 
tones for data transmission, rather than Bell 103 & Bell 121 tones, which are 
used only in the USA and canada AFAIK.  As most people now use at least 
V22bis, this is largely irrelevant.

Tony



+---------------+------------------------------+-------------------------+
|Tony Kidson    | ** PGP 2.2 Key by request ** |Voice +44 81 466 5127    |
|Morgan Towers, |  The Cat has had to move now |E-Mail(in order)         |
|Morgan Road,   |  as I've had to take the top |tony@morgan.demon.co.uk  |
|Bromley,       |  off of the machine.         |tny@cix.compulink.co.uk  |
|England BR1 3QE|Honda ST1100 -=<*>=- DoD# 0801|100024.301@compuserve.com|
+---------------+------------------------------+-------------------------+

Newsgroup: sci.electronics
Document_id: 54493
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & C

I was a bit surprised that the manual for my Fluke-87 multimeter
suggests applying WD-40 to the test lead sockets, especially the
current range socket.  The intention is to prevent the
test-lead-is-in-the-wrong-scocket beeper from going off when there
is no test lead in that socket.

The manual is a bit vague, but I think I'd apply the WD-40 to a
swab, then wipe the socket instead of spaying the stuff directly
from the can.

Speaking of said meters:  I compared the 87 against the 8060A that
I've had on my bench for almost 11 years.  It has been five years
since the 8060A has been calibrated.  On the DC scale, they agree
within .01 mV.  AC scale is within about .1 mV.  The 87 would be
just about the perfect portable meter if it had the dB scale; I
didn't feel it was worth the extra $100 for a second 8060 since I
don't use dB all that much in my work.

-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 54494
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Using generated power on large sound systems?

In article <1rk733$ekv@slack.sim.es.com> pashdown@slack.sim.es.com (Pete Ashdown) writes:
>
>I've bothered the rental shops and audio shops about the problem, but most of
>them have precious little experience in dealing with generated power.  My
>suspicion is that I don't really need anything larger than 2KW and this could
>all be resolved with a transformer of some sort.

Nope.  Your problem is either being caused by excessive voltage drop in the
long cable from the generator, or just plain not having enough power.  I
would suspect that those amps are going to draw a lot of current on short
peaks.

You can try using larger (and shorter) cables to the generator, or try
strapping the amps for 240V service and running 240V mains cables out,
which will minimize the line drop.  If these don't work, though, you're
going to need a bigger generator.

I assume that you're using well-maintained generators, and have watched the
voltage output on the generator properly.  If you don't have 120V coming out
of the unloaded generator you'll never get 120V at the other end.

>Can anyone offer any advice?  I want to do a lot of outdoor events this
>summer, and it would be nice if this power problem could be resolved easily.
>I've been looking into buying a power-pack so I could tap into junction boxes
>directly, but have no idea where to start.  One that would resolve my
>generator problems as well would be of high value to me.

I recommend you talk with an electrician who has experience in this sort of
work, and not with the pro-audio people.  Also, I recommend that you don't
try to tap into junction boxes at all, but hire a licensed electrician if
you don't really know what you are doing.  I've had to clean up after two
people who nearly killed themselves playing in hot 200A boxes, and it wasn't
much fun.
--scott

Newsgroup: sci.electronics
Document_id: 54495
From: kludge@grissom.larc.nasa.gov (Scott Dorsey)
Subject: Re: Accelerometer request re-specified

In article <1993Apr27.190648.26436@walter.bellcore.com> deaddio@ski.bellcore.com (Michael DeAddio) writes:
>
>Basically, I am looking for something to operate in the
>ranges of accelerations found in an automobile environment.
>I would like the device to operate as a trigger for other
>systems when the car's deceleration reaches a threshold value
>(which is how I assume some seat belt lock mechanisms and air
>bag deployment systems work?).

Open up one of the airbag control boxes.  They have inexpensive piezoelectric
accelerometers in them.  I know that the GM cars use the Setra units.  The
cheapest way to get such an accelerometer is to cannibalize an existing
automotive unit.

Incidentally, these things aren't very linear, but for the application they
would do a fine job.
--scott

Newsgroup: sci.electronics
Document_id: 54496
From: katop@astro.ocis.temple.edu (Chris Katopis)
Subject: Phantoms in my Sony STRVX550 Receiver


While I have gotten 8-9 years out of this digital receiver, it
has been acting VERRY strange of late.  I hope that  the following	
symptoms may help someone diagnose the error:

- i know that whatever lithium memory backup it had - has long died
thus if i unplug it - it won't remember the presets

- it has given up listening to the remote.  (i tried changing the remote's
batteries) when i try a remote function - the receiver registers that it
received it (a green remote light flashes) but the right function
doesn't happen - if any function at all.  (also strange- when i hit 
the "mute" button, for example, the display panel goes black - yikes-	
i've never seen that before ...)

- before all the strangeness started, the system turned itself OFF and ON
again - by itself

- sometimes it won't play a radio station, so i have to kinda twist it 
(yes kinda flex the motherboard, chasis) for it to get the radio
tuning back - the aux in function always works however....

it is inconvenient, but NOT inconvenient enough to pay an 
expensive repair fee.  while, i'm not a hardware guy, i wonder 
if something as simple as a surge supressor will be a quick fix.
the strange thing is that these symptoms come and go ...

someone told me this unit series has a bad Voltage Amp chip.

-anyway  ...arghh
-cjk
 

Newsgroup: sci.electronics
Document_id: 54497
From: stephens@geod.emr.ca (Dave Stephenson)
Subject: Re: solvent for duct-tape adhesive?

mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>>>
>>I don't know for sure that this will work, but you might try MEK (methyl
>>ethyl keytone?).  It worked getting the stickum left over from shelf paper,
>>and is available at paint stores.  Use a carbon gas mask and lots of
>>ventilation--this stuff really stinks!


>-- 
>:-  Michael A. Covington, Associate Research Scientist        :    *****
>:-  Artificial Intelligence Programs      mcovingt@ai.uga.edu :  *********
>:-  The University of Georgia              phone 706 542-0358 :   *  *  *
>:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI :  ** *** **  <><
If you use MEK for your sake wear safty glasses or better still
industrial goggles. The small est drop in the eye will casue
blindness by a catalysis reaction that is non cureavble once it starts.
The results are similar to mustard gas contamination. Note MEK peroxide
is a hardner form fibreglass resins.
--
Dave Stephenson
Geological Survey of Canada
Ottawa, Ontario, Canada
Internet: stephens@geod.emr.ca

Newsgroup: sci.electronics
Document_id: 54498
From: dwb@cbnewsb.cb.att.com (david.boyle)
Subject: Re: solvent for duct-tape adhesive?

> > mahy comments deleted........
> 
> RONG WRONG!!  Butane is used in a BUTANE lighter...Zippo's
> use petroleum naptha and perfume..
> BTW...if you wanna find some benzene...take a look at
> aerosol spray GUMOUT Carberetor Cleaner..that stuff will
> take of the adhesive..and the paint and melt plastic and
                                       ^^^^^^^^^^^^^^^
This doesn't melt plastic, at least it hasn't melted the plastic 
bottle that I bought it in yet.  Maybe I'd better go check that
bottle, its been sittin' awhile -:)

Newsgroup: sci.electronics
Document_id: 54499
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: **** And now serious: E-Magazine *****

In article <1993Apr27.152314.28798@donau.et.tudelft.nl> ferry@dutentb.et.tudelft.nl (Ferry Toth) writes:
>Subject: **** And now serious: E-Magazine *****
>Summary: How about starting a group where scientific articles can be pre-publish
>Keywords: Scientific papers, Electronic magazine
>
>For some time I've been thinking about the possibility of starting a group
>where scientific articles can be published (or perhaps just summaries).
>Possible advantages would be:
>* Free distribution
>* Fast acceptance
>* Online discussion between authors and readers
>
>This would be possible with one group with a moderator for publishing the
>articles and one perhaps without for discussion.


I think its a great, but idealistic idea. A reseacher will first of all try 
to publish a worthy paper in a credible, professional magazine and not in a 
community like USENET which is infamous for lots (not all) of junk 
information. The papers that will be "published" here will, in general, be 
of low quality. Also, it is improbable that any credit will be given to a 
researcher who publish here - and sadly, that is nowadays a main reason for 
publishing.

USENET is great for informal discussions and free exchange of ideas - keep 
it like that. A new, specialist group is just not worth it.

- gerrit

Newsgroup: sci.electronics
Document_id: 54500
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Why circuit boards are green?

Fiberglass boards are available in several colors.  Sitting right
here, I have unetched board stock that is white, blue, green and
yellow respectively.  I've also seen black boards.

Solder mask is available in a variety of colors too.  Depending on
the supplier, the color helps indentify the material.

Don't forget conformal coating.

I don't think I've seen phenolic impregnated paper boards in
anything other than the familar brown, but it would not be
difficult to add a dye to change the color.

-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu (140.220.1.1)    146.580: N8WED

Newsgroup: sci.electronics
Document_id: 54501
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: How to make the disks copy protected (continued)

In article <sehari.735962071@du139-201.cc.iastate.edu> sehari@iastate.edu (Babak Sehari) writes:
>From: sehari@iastate.edu (Babak Sehari)
>Subject: How to make the disks copy protected (continued)
>Date: Wed, 28 Apr 1993 01:54:31 GMT
>---
>
>The discussion under the old topic went in the wrong direction.  Some people,
>instead of discussing the issue itself, they decided to discuss the
>non-technical part of the issue.  So, Here I go with my limited knowledge
>about this issue.  Hoping you guys cut the crap and talk about the real
>technical ways to do this.  The methods that I am aware that are effective
>are:
>
>1- Laser hole burning.  This would leave the disk damaged, so if you format
>   that particular sector of the disk you can not write to it.  It is very 
                                           ^^^^^^^^^^^^^^^^^^^
Laser holes are (or were) used to prevent someone from making exact copies 
of a disk. You do not want to write to the damaged disk, only read and use 
the programs.

>   hard for crackers to damage the disk exactly the same way.
>

I remember a program called Copywrite that could copy a disk with a laser 
hole in it. I think it simulates the laser hole. After copying the disk the 
program is, if necessary, used in conjunction with a program called Nokey or 
something. (The program tells you which program to use)

No solution.

- gerrit

Newsgroup: sci.electronics
Document_id: 54502
From: CONRADIE@firga.sun.ac.za (Gerrit Conradie)
Subject: Re: info on flux gate coils/magnetometer?

In article <bbuck.735977235@Endor> bbuck@Endor.sim.es.com (Bryce Buck) writes:
>Subject: info on flux gate coils/magnetometer?
>Keywords: flux gate, magnetometer.
>I am interested in finding sources and design information on flux gate coils 
>or flux gate magnetometers (digital compass). Please respond via E-mail.

Sorry, my news reader doesn't want to reply.

1) Ling, S.C. "Fluxgate magetometer for Space Application", IEEE Journal 
Spacecraft, Vol. 1, No. 2, March-April 1964, pp 175-180.

Oldish, but usable. Background information

2) "Fluxgate magnetometry", Electronics world + Wireless world, September 
1991, pp. 726-732.

Great! Circuit diagrams etc for building an electronuc compass

- gerrit

Newsgroup: sci.electronics
Document_id: 54503
From: rdell@cbnewsf.cb.att.com (richard.b.dell)
Subject: Re: Lead ACid Batteries Part 2!!!

In article <C6728H.Luy@cbfsb.cb.att.com> rdell@cbnewsf.cb.att.com (richard.b.dell) writes:
>In article <1993Apr27.211036.1@ulkyvx.louisville.edu> jhwhit01@ulkyvx.louisville.edu writes:
>>In article <1993Apr26.221422.17208@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>>
><lots of stuff deleted>
>
>>The lead-acid secondary cell discharge reaction is EXOTHERMIC.  I am glad
>>you do not dispute this point.  If you don't want the lead storage battery
>>to discharge, it should be stored such that its charged state is the
>>equilibrium state.  During winter, the ground, be it covered with
>>concrete, dirt, or wood, maintains a cooler temperature on average than
>>the surrounding air or the battery.  The heat capacity of air is less than
>>that of concrete, dirt, or wood, so it heats faster.  Conversely, air cools
>>faster, too.
>>
>>The normal storage procedure for a battery is to leave it in an unheated
>>garage or basement.  The storage surface is often cooler than the
>>surrounding air, with the battery temperature somewhere in-between.  E.g.,
>>the basement air temperature may be 70 F, the floor temperature 65 F, and
>>the battery temperature 66 F.
>>
>>The air temperature is HIGHER than the battery temperature.  The heat of
>>reaction is not going to move up the gradient.  The floor temperature is
>>LOWER than the battery temperature, and heat is going to move to it.  The
>>floor is an incredible heat sink.
>>
>
>Might depend on where you live .. I know locally, for most of the winter
>the ground, and concrete floor, within sheds and garages (unheated) is
>signifacantly warmer than the average air temperature.  The air does get
>warmer during the day, but during the night, the ground and concrete
>is definitely warmer, especially when protected by the walls from the
>albedo effect.  And the nights are longer by several hours than the
>days.
>
><rest of quoted text deleted>
>>
>>Jeff White       jhwhit01@ulkyvx.louisville.edu
>
>Richard Dell

Sorry about following up my own article, but I wanted to continue
that what might be being missed here is that the important thing
might not be temperature differences per se, but the action of
heat sinking the battery.

Perhap someone could conduct an experiment, taking two identical
lead acid batteries, placing both on wooden shelves, but putting
one of them in a water bath designed to act as a heat sink.  This
would eliminate the 'concrete floor effect', and keep both batteries
at the same ambient temperature.

I think the argument over temperatures is not pertinent, but the
one over heat conductance and removing the exothermic heat may have
some validity.

Richard Dell


