HDTenEightyP/NetNews huggingface dataset:
From: ingram@hotair.enet.dec.com (Larry J. Ingram)
Subject: Re: Radar Detectors, and Radar Detector Detectors
Organization: Digital Equipment Corporation
Date: Thu, 23 Jul 1992 22:10:31 GMT


In article <1992Jul23.204831.28487@news.columbia.edu>, gmw1@cunixa.cc.columbia.edu (Gabe M Wiener) writes...
>In article <92Jul23.162259edt.176@orasis.vis.toronto.edu> oliverb@vis.toronto.edu (Oliver Bengtsson) writes:
>>   Could someone out there please tell me how a radar detector detector
>>works? I thought that a radar detector was a passive device, nothing more
>>than a receiver tuned into detect a certain radio frequency used in radar
>>guns. If this is the case, how can they be detected?  
> 
>All receivers work by resonance, and this resonance can be detected with
>the appropriate equipment.

	A very simple way that cops "detect" radar detectors is to occasionally
	turn on their radar while driving down the highway. The officer
	simply looks for the car(s) whose brake lights suddenly come on.

Larry
Organization: Queen's University at Kingston
Date: Sunday, 26 Jul 1992 14:31:20 EDT
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: 0.100" spacing
 <1992Jul26.065031.10461@uniwa.uwa.edu.au>

In article <1992Jul26.065031.10461@uniwa.uwa.edu.au>, gude@uniwa.uwa.edu.au
(David J W Emrich) says:

>.... stuff deleted.... (About lining up dips for drilling)
>
>the DIPs later on.  My solution was to make up several jigs to use when
>drilling the IC holes.
>
>First, get hold of an old commercial PCB that you don't want any more,
>with lots of DIPs on it.  Preferrably at least a 22-pin and a 48-pin DIP

or a good piece of Breadboard that already have grids of holes lined up
at 0.1".  Easier that way.

>(I think 22 is the longest .3" wide DIP and 48 is the longest .6" wide

There are manufacturers making 28 pins DIP's at 0.3" to save space.
You are probably right about 48 pins package.  Most of the higher pin
count chips goes to PLCC or PGA.

>DIP).  The idea is to find the longest available DIPs at whatever widths
>you use.  You can use the 22pin jig to drill anywhere from 8-pin up to
>22-pin DIPs.

>To use the jigs, just line them up with the copper pads, by holding the
>PCB up to the light, and clamp the jig (parallel clamps are the best,
>but G-clamps are quite OK).  Then drill away!

I used to do the same using breadboard as jigs.  These days I leave a
donut hole in the middle of the pad to guide the drill bit, but hey
I got a new prescription recently. :)

>
>It's still fiddly, but it is quite a bit quicker than eye-sight
>guessing, and a lot less optically stressful!
>
>Hope this is of some use.
>
>David Emrich
>gude@uniwa.uwa.edu.au

K. C. Lee
Elec. Eng. Grad. Student
Newsgroups: sci.electronics,rec.audio
From: despair@netcom.com (Scott Hanson)
Subject: Re: Life after CDs
Date: Thu, 30 Jul 92 02:26:29 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

In article <Brr3A6.5IA@news.cso.uiuc.edu> tmkk@uiuc.edu (Khan) writes:
>
>In article <1992Jul20.192541.1069@access.usask.ca> choy@skorpio.usask.ca writes:
>>CDs are obsolete. What comes next?
>
>Hmm... Well, LDs are 12" (like records) and analog (like records)...
>Maybe the next generation is a 12" sound-only analog LD. Surely this
>would make the die-hard-vinyl-LP-loving crowd happy? And think of the
>capacity! CLV LDs can cram 60 minutes of video per side. Audio, with its
>much lower bandwidth requirements, could probably fit several hours per
>side.
>
>Comments?
>

I don't understand the question.  I put Laserdisks on my record player and
listen to them all the time.  It became my favorite kind of music quite some
time ago.

Perplexed.

-- 
Scott Hanson		This has been a recording.
despair@netcom.com
Newsgroups: sci.electronics
From: medin@catbyte.NoSubdomain.NoDomain (Dave Medin)
Subject: Re: 20W Audio amplifier chip TDA1520
Keywords: Radio Shack, Philips
Reply-To: medin@catbyte.b30.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Distribution: usa
Date: Thu, 23 Jul 1992 16:01:53 GMT

In article <64120@hydra.gatech.EDU>, gt8021a@prism.gatech.EDU (EASON) writes:
|> ..
|> A couple of years back, I wandered into a Radio Shack at lunchtime, and they
|> had a closeout on these Philips TDA1520A (& TDA1520B) single-chip "20W Hi-Fi
|> Audio Amplifiers."  I bought a couple with the intention of building a pair
|> of self-amplified bookshelf speakers for my synthesizer (or whatever).  I'm
|> just getting around to the project (sound familiar?), and I was wondering if
|> anyone else had used these chips before.  Any caveats?  Is the "Test & appli-
|> cation circuit" correct?  Parts of it look suspicious, but my op-amps course
|> was too many unused years ago.
|> 
|> I remember that RS had a (10W?) stereo audio amp chip, but these are single-
|> channel.  The chip is a 9-pin SIP with dimensions around .5" x 1" x .2".
|>                  ___________
|>                 | TDA1520A  |
|>                  )         ( 
|>                 |___________|
|> 	          ||||||||| 
|> 	          ||||||||| 

The TDA-1520 was a joy to work with (I rebuilt broadcast line amps with
them with good results). Make sure to decouple the power
supply with a 47uF electrolytic in parallel with a 0.1uf ceramic
cap for near trouble-free operation. It needs to be heat sunk
when operated near its 40 volt maximum supply voltage, as the bias
current is in the vicinity of 60 ma and the device will thermal-limit in
free air.

The reason the ap circuit might look suspicious is that the part is
designed to use a single supply rail, and thus has support circuitry
to generate a virtual ground about halfway between V+ and ground.
The input and output must be capacitively coupled when using a single
supply.

The sonic performance of this part is still the best among audio
power IC's.

Digi-Key still sells the 1520, BTW. The Philips/Signetics ap notes
were correct, but I don't know about Radio Shack's.

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

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

 * The opinions expressed here are mine (or those of my machine)
From: laird@stable.ecn.purdue.edu (Kyler Laird)
Newsgroups: sci.electronics
Subject: IEE-488/GPIB/HPIB - HELP!  Need info and sources of PC cards.
Date: 23 Jul 92 16:40:17 GMT
Organization: Purdue University Engineering Computer Network

I need to interface a PC to an FFT analyzer.  It has a GPIB interface.

It seems like I've seen lots of PC (ISA bus) interface cards for this in
the backs of PC Magazine and Circuit Cellar, but I didn't find any this
morning.

Anyone have good experience with such a project?  I need software too,
I assume.

Thanks for the help!

--kyler
Xref: sparky sci.electronics:13514 rec.audio:10966 alt.folklore.computers:11329
From: ultima@mcl.ucsb.edu (David Rosen)
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
Subject: Re: Life after CDs
Date: 28 Jul 92 22:44:19 GMT
Followup-To: sci.electronics

In <1992Jul24.195249.4172@coli.uni-sb.de> chbl@sbustd.rz.uni-sb.de (Christian Blum) writes:
>smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC) writes:
>> In article <1992Jul23.041115.20377@bilver.uucp>, bill@bilver.uucp (Bill Vermillion) writes:
>> There is a story (probably apocryphal, anyone know?) that the 74 minutes
>> time was chosen because it was just long enough to hold the Sony MD's wife's favourite piece of classical music...
>Sorry that I don't know about your story, but I do know that I've got a CD
>with 76 minutes of music on it... and I've seen one with 77 minutes!

I used to think the max was 76 minutes, until I got one that had 79
minutes!  I was thinking it might be just those blank spaces that they
put in--you know, the countdown in between songs, about 3 seconds
usually.  Maybe if those were removed, it might be less...

--Dave
ultima@mcl.mcl.ucsb.edu
From: nagle@netcom.com (John Nagle)
Newsgroups: sci.electronics
Subject: Re: Green Layer on Circuit Boards?
Date: 23 Jul 92 17:08:12 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

adw@cci632.cci.com (Allen Williams (co-op)) writes:
> I have made some circuit boards ...

> However, one step that I think would be a good addition is the green
>layer of plastic insulation that commercial circuit boards have. ...

> Is it possible to add this layer of green insulation on do-it-yourself
>boards? ...

> Although it's not absolutely necessary to have insulated traces, I feel 
>that it would be better in the long run to reduce the chances of short
>circuits as boards tend to accumulate dust and crud during long term use.

      The green "solder mask" layer is really an aid to wave-soldering of
high-density boards, not a protection for the board after manufacture.
If you want to protect your finished (stuffed, soldered, and tested)
board from exposure, what you want is a conformal coating like Fine-L-Coat
from Tech Spray.  You spray this on the finished board (masking connectors,
pots, etc.) and it "shrink-wraps" the board with a clear, waterproof coat.
Conformal coats are widely used for military, marine, aircraft, and
automotive electronics, but rarely for office products.  There are
other kinds of conformal coats; some are dip baths for production work,
but the sprays are easier for small-scale jobs.

      Fine-L-Coat Remover is available if you have to make board repairs.

					John Nagle
From: gbchoy@taco.ucdavis.edu (Garett Brandon Choy)
Newsgroups: sci.electronics
Subject: DMM w/inductance
Date: 22 Jul 92 22:19:53 GMT
Organization: College of Engineering - University of California - Davis

Please respond by email to (gbchoy@taco.ucdavis.edu)

A little while ago, I asked about DMM's made by Kelvin.  Thanks for the
responses.

I realized I forgot to include something:

I'm trying to find a fairly good DMM that can read capacitance and INDUCTANCE.
Preferably around the $100 range. Any suggestions?

Garett
.
From: rmf@bpdsun1.uucp (Rob Finley)
Newsgroups: sci.electronics
Subject: Re: Green Layer on Circuit Boards?
Date: 25 Jul 92 17:35:29 GMT
Organization: Harris Allied Broadcast Div., Quincy, IL

In article <1992Jul21.134601.8985@cci632.cci.com> adw@cci632.cci.com (Allen Williams (co-op)) writes:
>
> However, one step that I think would be a good addition is the green
>layer of plastic insulation that commercial circuit boards have. I've looked
>in the Mouser and Digi-Key catalogs, and can't find anything that looks like
>the type of insulation that would go on top of the traces.
>
> Is it possible to add this layer of green insulation on do-it-yourself
>boards? Or do you have to cut all these holes for the pads before applying
>it, making it uneconomical to use unless you make ten thousand copies using
>a cutter press? Or is it applied by using big and expensive machinery? 
>
> Although it's not absolutely necessary to have insulated traces, I feel 
>that it would be better in the long run to reduce the chances of short
>circuits as boards tend to accumulate dust and crud during long term use.


This is going to be rather hard to do as it is usually applied using a 
silkscreen method.  There is a photoimageable film but I haven't seen
it either.

The plastic coating is called a soldermask.  It not only protects the
board from corrosive enviroments but mainly allows the board to 
be flow or dip soldered with a minimum of bridging. 

You might get adequate results merely tin-plating the board.  I have
never seen a home soldermask method but would be interested.

Best Regards

Robert
Newsgroups: sci.electronics
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Airport X-Rays
Date: Sun, 26 Jul 1992 02:08:52 GMT
Organization: U of Toronto Zoology

In article <4836@unixhub.SLAC.Stanford.EDU> ralph@falcon.SLAC.Stanford.EDU (Ralph Becker-Szendy) writes:
>After all, EPROMs are erased by UV, do they resist the airport X-ray
>machine? I'd guess that the X-rays are heavily attenuated by the case
>of the EPROM (the top of which is transparent to UV light but not to
>X-rays), but is there real danger to EPROMs ?

People who have *tried* to erase OTP EPROMs (EPROMs in non-windowed
packages) with X-ray machines say that it seems to be effectively
impossible, even with hours-long exposures.  Certainly you're not going
to do it with a device that won't fog most types of film.
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  henry@zoo.toronto.edu  utzoo!henry
Newsgroups: sci.electronics
From: johnh@macadammq.edu.au (John Haddy)
Subject: Re: White noise generator.....
Organization: Macquarie University, School of Mathematics, Physics, Computing and Electronics
Date: Mon, 27 Jul 1992 22:33:25 GMT

In article <9981@sun13.scri.fsu.edu>, nall@sun8.scri.fsu.edu (John Nall) writes:
|> Since I did fairly well at getting my previous question answered
|> on this newsgroup, thought I'd push my luck and ask another :-)
|> 
|> I'm one of those people who has to have some "white noise" in the
|> background to sleep.

|> ...[stuff deleted]

|> Anyway...finally....it seems to me that if there is a sound-generator
|> chip available, that a little portable unit could be made, which would
|> run on ni-cad batteries (so that it could be recharged), with a small
|> speaker such as is found in a cheap transistor radio.  If put close to
|> the ear when sleeping, it should do the trick.
|> 
|> Does anyone know of such a device?  If not, is there a such a noise-
|> generator chip available?  (I don't have access to any sort of technical
|> material on what chips are available these days).
|> 
White noise generation can be fairly easily accomplished by amplifying the shot
noise from a zener diode. Refer to Horowitz & Hill for a reasonable discussion on
noise.

Another easy way to generate noise is given in Horowitz and Hill. A simple pink
noise source circuit is given which uses an MM5837 digital noise source chip (a
pseudo-random white noise generator) and a shaping network. Of course, you could
easily use a straight PN generator to provide band-limited white noise. Don't be
discouraged if you cant find this particular chip - PN generators can be made
with a shift register and an XOR gate.

Refer to Horowitz and Hill - "The Art of Electronics" (which 90% of people on the
net will tell you is the "Bible" of the electronics world: one aquaintance of
mine maintains that were he ever to be stuck on a desert island with only one
reference work, it would be Horowitz & Hill (how one would perform electronics on
a desert island with no electricity is another matter :-))

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

      |  _  |_   _   |_|  _   _|  _|              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

----------------------------------------------------------------------------
From: nagle@netcom.com (John Nagle)
Newsgroups: sci.electronics
Subject: Re: How can I make RF-coils
Date: 28 Jul 92 18:11:51 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

tsjoit@htsa.aha.nl (T. H. Tsim) writes:


> 
>Hi! Dear netters !
> 
>In order to construct a RF-mixer oscillator, I need some info concerning
>RF inductivity-coils. You know, those small copper cans, which contains a
>plastic winding body and a turnable ferrit core.
> 
>Could someone please tell me how to design such a device ? What kind of
>calculations should be made on diameter, wire thickness, ferrit length etc etc

      See chapter 4, "Winding your own coils", in "Secrets of RF Circuit
Design", by Joseph J. Carr.  (1991, TAB (blech) Books, ISBN 0-8306-3710-9).
Like most TAB books, this is a marginally useful work; despite the title
much of the content is devoted to such subjects as a history of spark
gap transmitters (with diagrams and photos) and techniques for refurbishing
old ham gear.  But it does have a useful chapter on do-it-yourself coil
making.

      But why bother?  Between Coilcraft and Toko, you can get coils for
almost any receiver application for a dollar or two each.  The minimum
order quantities can be a problem, but Coilcraft has some designer's kits
with a few of each value for each type of coil they make.  These run
$50-60, and if you use up all of one kind, they'll restock your kit free
if you ask.  Coilcraft is at 708-639-6400.  I've found them very helpful.

					John Nagle

					John Nagle
Newsgroups: sci.electronics
From: sasarh@demetris.unx.sas.com (Tony Hefner)
Subject: Where to get the BA1404 and crystal
Originator: sasarh@demetris.unx.sas.com
Date: Thu, 30 Jul 1992 19:51:27 GMT
Organization: SAS Institute Inc.
Keywords: FM BA1404


Sorry to bring this up again, but I recall a post where someone had found a
source for the BA1404 stereo transmitter, a crystal, and the data sheet.
I can't locate the article, and I need one of these beasties to rig up some
remote speakers.  Could some kind soul who saved away the information please
e-mail it to me.

                                   Thanks,

                                    -- Tony Hefner (aka sasarh@unx.sas.com)
From: jon%vector0.UUCP@sactoh0.SAC.CA.US (Dazed N. Confused)
Newsgroups: sci.electronics
Subject: Re: SHOCKING STORIES
Date: Thu, 23 Jul 92 09:23:45 PDT
Organization: Vector Zero

wtm@uhura.neoucom.edu (Bill Mayhew) writes:

>                Most of all, I make sure that someone is within
> sight and knows that I'm working on live equipment and that person
> knows safety rules and how to sommon help.  Even if you're careful,
> there is always the possibility of a mistake.

     Um, what's the medical procedure for a very bad shock?  I didn't
think there was any, besides grounding the body.  Is it related to
fire exposure, as voltage can often cook parts?

--Jon

   jon%vector0@sactoh0.SAC.CA.US                Life is like a kiwi.
   PacBell.COM!sactoh0!vector0!jon


Newsgroups: sci.electronics
From: dbushong@wang.com (Dave Bushong)
Subject: Re: Underground CD copying
Organization: Wang Labs, Lowell MA, USA
Date: Tue, 21 Jul 92 23:41:12 GMT

klp@doe.carleton.ca (Ka Lun Pang) writes:


>Hi folks,

>More than one person have told me that some crooks have been making illegal 
>copies of CDs. And one told me that those CDs are worse in fidelity.

>I don't know the details of making a CD but as I understood, there are 
>micro hills and valleys representing 1's and 0's. Now if the bad guys have
>the technology of manufacturing CD, which part(s) of the process they can't do
>perfectly to cause degradation in fidelity?

It's not hills and valleys, but more like a series of potholes.  The
infidelity would come from their source material (for example, they
might take a cassette recording and make a CD master with it).  The
CD media cost in any volume is around 90 cents each, so with no
royalties, no performance fees, it would be pretty lucrative!

Dave
-- 
==========================================================================
Dave Bushong, KZ1O@K1UGM.MA         +    No .sig, no tattoo, 
Wang Laboratories, Inc.             +        no bald spot, no nothin!!
Internet: dbushong@wang.com         +-------------------------------------
Project leader, OCR Products        + (reserved for future expansion)
Newsgroups: sci.electronics
From: cab@col.hp.com (Chris Best)
Subject: Re: Typewriterconversion
Date: Thu, 23 Jul 1992 17:05:09 GMT
Organization: your service

> Hi.  I have an Smith-Corona electric typewriter that has a memory on
> ...
> this typewriter and convert it into a daisey-wheel printer for a computer?

----------

Check with Smith-Corona - maybe they have an adapter that lets you do
just that.  I think that some electric typewriters have this option,
so you may be lucky.
Newsgroups: sci.electronics
From: pchris@dcc.uchile.cl (Chris Perleberg)
Subject: Problems with 8031 Serial Port
Originator: pchris@pehuen
Date: Wed, 29 Jul 1992 22:42:36 GMT
Reply-To: pchris@dcc.uchile.cl
Organization: Universidad de Chile, Depto. de Ciencias de la Computacion


We're having problems with the serial port on a 8031.  We're programming the
serial port in mode 1, frame of 8 bits, taking the baud rate from the chip
clock (3.6864 MHz) and dividing it by Timer1.  Unfortunately, the baud rate
of the transmitted characters never changes no matter what value we put in
the hi byte of Timer1, TH1.  The baud rate that we receive is about 14,700
baud.  Anyone have any ideas as to what may be going on?

Thanks,
	Chris Perleberg
	pchris@dcc.uchile.cl
Newsgroups: sci.electronics
From: billg@bony1.bony.com (Bill Gripp)
Subject: Re: SHOCKING STORIES
Organization: LA&W RR
Date: Wed, 22 Jul 92 14:55:23 GMT

A number of years ago I worked with a guy at a summer job whose brother
had a near fatal experience.  They were playing near the RR in the Bronx
(New Yawk) when his brother fell off the top of a steap embankment.  His
natural reaction was to grab that wire so he wouldn't fall.  Only
problem was that wire provided 11kVAC to drive the electric trains.  He
said his brother only survived because the path the current took through
his body did not pass through his heart.

Take it for what it's worth.
From: mdk@col.hp.com (Mark Keisling)
Newsgroups: sci.electronics
Subject: Re: Color LCDs with VGA Quality
Date: 31 Jul 92 20:52:16 GMT
Organization: HP Colorado Springs Division

jkelly@oodis01.af.mil (Jerry Kelly) writes:
> Do any of you know where I can get information on Color LCDs?
> I need a large color LCD display hopefully with VGA quality.
> Does such a display exist?
> 
> jerry kelly
> jkelly@oodis01.af.mil

We are currently using a Sharp Active Matrix Color LCD in our LAN tester.
The display area is about 8.25 x 6.25 inches.  The display is 640x480 pixels 
and each pixel can display 512 colors.  I'm sure your local Sharp rep
can get you more info on their latest displays.

Mark.
Newsgroups: sci.electronics
From: tchannon@black.demon.co.uk (Tim Channon)
Subject: Gerber previewers / converters 
Distribution: world
Organization: null
Date: Thu, 23 Jul 1992 01:21:15 +0000

> Is that "GC-PREVUE" an executable?  For {DOS, MacOS, UNIX, ???} ?
> 
Executable for ibm compat pc under msdos.

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
From: pegasus@csd4.csd.uwm.edu (David R Hucke)
Newsgroups: sci.electronics
Subject: Using a PNP Transistor as a buffer...
Date: 31 Jul 92 03:01:26 GMT
Organization: Computing Services Division, University of Wisconsin - Milwaukee
Originator: pegasus@csd4.csd.uwm.edu

Ok....

I understand (i think) how one uses an NPN transistor as a buffer for an
LED when driven by a micro-controllers port..

Now, could somebody explain to me how this would work for a PNP transistor?


Thank you very much again....



-- 
pegasus@csd4.csd.uwm.edu                David R. Hucke
                                        UW-Milwaukee Film Major
--