HDTenEightyP/NetNews huggingface dataset:
From: moroney@ramblr.enet.dec.com
Newsgroups: sci.electronics,rec.bicycles,rec.motorcycles
Subject: Re: Sticky Demand Traffic Light problem solution
Date: 13 Apr 92 19:00:52 GMT
Reply-To: moroney@ramblr.enet.dec.com ()
Organization: Digital Equipment Corporation


In article <-slj0+=.jps@netcom.com> jps@netcom.com (John Serafin) writes:
> sagerian@delphinium.UUCP (Steve M. Sagerian) writes:
> 
> >I fact I was supprised no one mention that aluminum (sp?) wheels have no effect on the sensor at all.
> 
> Then how does an aluminum frame with aluminum wheels trip sensors?
> (It happens frequently.)
> >Stever

These things (at least the more common type) detect eddy currents, which means
enough metal (regardless of whether it is magnetic or not).  It really senses
conductivity.

I watched them install one of these things in front of my old house, the sensor
is just a loop of wire (3-4 turns) placed into an approximately rectangular
saw cut into the pavement, then the cut is filled with tar.

This particular sensor could be triggered reliably with a piece of aluminum
foil placed over the sensor within a couple inches of the pavement.
This told me that magnetic materials are _not_ needed, as last I knew, aluminum
was not magnetic.

The sensitivity seemed to be proportional to the area of the sensee, and
being close to the pavement was also important.  The most sensitive
area seemed to be just inside the edge of the box.  Bikers take note.

-Mike
Newsgroups: sci.electronics
From: twilhite@isis.cs.du.edu (Timothy R. Wilhite)
Subject: CIRCUIT SIMULATION PROGRAM
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Mon, 13 Apr 92 13:00:39 GMT

I am looking for a shareware of public domain package that allows you
to build analog or digital circuits and test them.  I want to thank every-
one that replied regarding the Electronic Workbench.  I want to see if there
is anything out available before I put the money down.  Thanks in advance.
From: francis@ircam.fr (Joseph Francis)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 6 Apr 92 13:17:09 GMT
Organization: IRCAM, Paris (France)

In article <9204050203.AA29602@cmr.ncsl.nist.gov> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
>
>-From: etsai@athena.mit.edu (Eugene C Tsai)
>>Newsgroups: sci.electronics
>>Subject: Jacob's Ladder
>>Date: 3 Apr 92 07:48:03 GMT
>>Organization: Massachusetts Institute of Technology
>
>>I have a friend who wants to build a device called a Jacob's Ladder.
>>It is a device commonly seen in sci-fi/horror movies.... it has two
...

>There's one very easy way:
>  - Get a big old neon sign transformer.

I believe that is a great way to get the crap knocked out of you. I
made this stuff when I was a teenager with car spark coils and
high-current 12v oscillators. I could actually touch a bare wire
(accidentally) and aside from a queer electrical shock (a feeling
which seems to have lasted... smirk) it had no nasty effects. I'm
trying to remember the actual configuration, I think I used a
120v<->12v transformer at one stage, and then used some sort of simple
high-current transistor for a high-frequency oscillator. I can't
remember the name of the electronic element for the life of me. Of course
the whole setup was only about 12" high...


-- 
| Le Jojo: Fresh 'n' Clean, speaking out to the way you want to live
| today; American - All American; doing, a bit so, and even more so.
From: berger@atropa (Mike Berger)
Newsgroups: sci.electronics
Subject: Re: DC Shock
Date: 11 Apr 92 19:51:25 GMT
Article-I.D.: ux1.1992Apr11.195125.9468
Organization: University of Illinois at Urbana

dino@inqmind.bison.mb.ca (Tony stewart) writes:
>jon@sparcplug.et.iupui.EDU (Jon Burgoyne) writes:

>> I'm looking for a small circuit that could provide a shock to my dog.  This i
>> to build a collar similiar to the invisible fence product.  I believe they us
>> a 22.5v bat.
>> 
>> The RF part I can probably struggle through but producing a shock was not
>> something they taught us in school.
>> 
>> Any help appreciated.
>> 
>> Jon Burgoyne
>> Purdue University - Indianapolis
>> jon@sparcplug.cadcam.iupui.edu

>TO generate shocks, all you need is a simple clock circuit (CMOS SCHMITT 
*----
Why does anybody want to help this guy torture his dog?
--
	Mike Berger
	Department of Statistics, University of Illinois
	AT&TNET     217-244-6067
	Internet    berger@atropa.stat.uiuc.edu
From: mpaul@unlinfo.unl.edu (marxhausen paul)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 10 Apr 92 17:37:30 GMT
Article-I.D.: unlinfo.1992Apr10.173730.19726
Distribution: na
Organization: University of Nebraska - Lincoln

THis is probably mentioned in a different followup and ought to be common 
knowledge, but besides the shock/fire/UV radiation hazards of Jacob's Ladders,
they kick out radio frequency interference like nothing else you can build.
Building on to leave going all the time as a techno-knick-knack is contrain-
dicated as you will be screwing up the radio/TV reception in your house and
possibly in your neighbor's house/apartment.  Not a civil thing to do.

-- 
paul marxhausen ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "when i was six I could paint like
university of nebraska - lincoln ~~~~~~~~~~ raphael - it has taken me my entire
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ life to learn to paint like a child."
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - Pablo Picasso 
Newsgroups: sci.electronics
From: dmturne@ptsfa.PacBell.COM (Dave Turner)
Subject: Re: goodbye Heathkits
Reply-To: dmturne@PacBell.COM (Dave Turner)
Organization: Pacific * Bell, San Ramon, CA
Date: Wed, 8 Apr 1992 00:15:35 GMT

In article <6178@public.BTR.COM> thad@public.BTR.COM (Thaddeus P. Floryan) writes:
>
>Though I've built more than a fair share of Heathkits over the years, I've
>also enjoyed the (almost raw) kits from Old Colony (the kit (mostly parts))
>operation of The Audio Amateur and Speaker Builder publications.
>
>Does anyone know if they're still around?  I believe they were located in
>New Hampshire.
>
They must be; they advertise in Elektor.
Their ads have a Peterborough, NH address (same as Elektor).


Elektor Electronics USA
P.O. Box 876
Peterborough, NH 03458-0876

(603) 924-9464
(603) 924-9467 FAX

I don't have the address or phone number for Old Colony.

-- 
Dave Turner	(510) 823-2001	{att,bellcore,sun,ames,decwrl}!pacbell!dmturne
From: Jeff.Lindstrom@ofa123.fidonet.org (Jeff Lindstrom)
Newsgroups: sci.electronics
Subject: Re: question about RC circuits for timing purposes
Date: Thu, 09 Apr 92 01:10:06 PDT
Organization: Universal Electronics Inc. (Public access BBS)

  I would suggest using a HexFET instead of the transistor.  With no base current, the circuit would work better.



--  

Jeff Lindstrom
Internet: Jeff.Lindstrom@ofa123.fidonet.org
Compuserve: >internet:Jeff.Lindstrom@ofa123.fidonet.org
Xref: sparky sci.electronics:8494 rec.audio:7402
From: matgbb@lure.latrobe.edu.au
Newsgroups: sci.electronics,rec.audio
Subject: Re: Slew Rate & distortion was (Re: requesting CD player advice)
Date: 14 Apr 92 11:23:02 GMT
Organization: VAX Cluster, Computer Centre, La Trobe University

In article <se0biINNaaa@network.ucsd.edu>, mbk@lyapunov.ucsd.edu (Matt Kennel) writes:
> kludge@grissom.larc.nasa.gov ( Scott Dorsey) writes:
> : 
> : How are you measuring distortion?  I gather that you are talking about a
> : THD rating, but a system that has a poor slew rate may have excellent THD
> : and still sound poor because it doesn't follow transients well.
> 
> I don't understand.  How is having a 'poor slew rate' any difference from
> high-frequency dropoff in response?  Intuitively, they seem to be
> two ways of describing the same thing, though "poor slew rate" provides
> a bit more physical intuition.
> 
> Or perhaps "poor slew rate" is a code word for "distortion at high
> frequencies"?
>                                       
As I understand it, poor slew rate is the cause of the audiophiles hero of
a few years back, Transient Intermodulation Distortion. The idea is that
if an amp is fed 2 or more signals simultaneously, 1 of them ultra-sonic,
the amp will not be able swing its output (slew) fast enough, so the 
differential input stage will become non-linear due to the late arriving
feedback. Hence it acts as a mixer, and produces sum and difference frequencies
in the audio band (intermodulation products), which sound yucky. There was
a recent article by Cherry in J. AES on different forms of IMD. There
is also the IEC high frequency difference test for amplifiers, which is a
pretty good objective method of looking for it. 

IMD is a good candidate for CD distortions for two reasons: Some (particularly
expensive audiophile types) produce lots of RF on the output, which could
upset amps further downstream. Second, the analogue stages in the CD player
have to cope with step-like output from the dac. This is why the op-amps
on the TDA 1547 dac are rated at (from memory) 200V/us, as opposed
to 13 for an NE5534 or 0.4 for an LM741 (hopefully such devices are no longer
found in audio amps).

It can't be measured simply as high frequency distortion, because the
distortion products resulting from a *monotone* will be so far out of band
that they will be killed by the output filters. However, the 19kHz/20kHz
IM test result is printed by most decent magazines: the differences are fairly
evident. It is quite possible such things are audible, since the test tones
are inaudible (to most everyone) and the difference tone (distortion)
is generated at 1kHz, totally unmasked by the original signal.

Interestingly, CD players with excellent IM results (Yamaha CDX1050,
Technics SL-PS 900) are usually bagged for sounding 'lifeless' or 'boring',
while those which measure to be inferior (eg Philips) get praised for
'dynamism', 'pace', 'rhythm' and 'timing'.

Graham B
From: gsteckel@vergil.East.Sun.COM (Geoff Steckel - Sun BOS Hardware CONTRACTOR)
Newsgroups: sci.electronics
Subject: Re: need help identifying component (Repost with corrections)
Date: 17 Apr 92 19:58:59 GMT
Reply-To: gsteckel@east.sun.com (Geoff Steckel - Sun BOS Hardware CONTRACTOR)
Organization: Omnivore Technology, Newton, Mass. (617)332-9252
NNTP-Posting-Host: vergil.east.sun.com

In article <1992Apr17.183517.11886@hubcap.clemson.edu> raghutp@hubcap.clemson.edu (Raghu Toppur) writes:
>There are no schematics available, and the Technical Assistance number is
>defunct. The problem is "obviously" :) in what seems to be a really fancy
>power supply board. There is one part here on the 115V side,
>which I have no idea what it is. 
>
>It sort of looks like a small SilverOxide battery which has been dipped in 
>tar, and has two leads emanating from it. Says CAL-R 2SS40 on it...

This is probably a MOV (Metal Oxide Varistor) if it is in parallel with
the power line, or a NTC (negative temperature coefficient) resistor, if
it is in series.  It's probably the latter; these have high resistance
when cold and low resistance when hot.  They are used to limit the surge
current when you turn on the power supply when the input capacitors are
not charged.  When the system is running, the NTC is hot and presents
very little resistance to the circuit.

The Digi-key catalog lists both NTC resistors (Keystone) and MOVs.

I suspect it would be much, much easier to replace the power supply
than to fix it.  If it is blowing 5A fuses look at the input bridge,
main capacitors, and main switching transistors.  However, some 3rd
component may have failed and you could waste a lot of time and
transistors looking for it.

	regards,
	geoff steckel (gwes@wjh12.harvard.EDU)
			(...!husc6!wjh12!omnivore!gws)
Disclaimer: I am not affiliated with Sun Microsystems, despite the From: line.
This posting is entirely the author's responsibility.
Xref: sparky sci.electronics:8362 comp.robotics:982
From: al152931@mtecv2.mty.itesm.mx
Newsgroups: sci.electronics,comp.robotics
Subject: HELP!: i need the manual of AVSIM51
Date: 12 Apr 92 02:32:41 GMT
Reply-To: al152931@mtecv2.mty.itesm.mx
Distribution: alt


     hi! 
         Do you have the manual of AVSIM51?
         Here,in Mexico,i can't find it!
         if you can give me a copy,i'd be eternally grateful!!

  send me e-mail for response,please,to:
         al152931@mtecv2.mty.itesm.mx

  my name and address is:
               
          Aaron Sari~ana Toledo
          Filosofos 301,Depto. 303-C
          Col. Tecnologico
          Monterrey, N.L.
          Mexico
                                     thanks!!
Newsgroups: sci.electronics,rec.audio
From: apolivka@x102a.harris-atd.com (polivka al 60047)
Subject: Digital Audio Bandwidth Compressor wanted
Organization: Harris Gov't Aerospace Systems Division
Date: Thu, 16 Apr 1992 17:26:11 GMT

 (Please forgive me if you've seen this before, but I think it did not
  cross-post to this newsgroup the first time.)

I would like any information about or where to find a digital audio
bandwidth compressor that provides reasonable quality audio at about
20 to 30 kb/s (or less).

By "reasonable quality audio", I mean something that is at least AM
radio quality, or maybe a little better.  I want to use this
compressor for both music and voice.

I do not require stereo, although I might consider using it.
Monophonic would suffice.

I require very little dynamic range.  The ideal compressor would
perform a lot of dynamic range compression as well as other
methods (removal of redundancy, etc.) to achieve bit rate compression.
The ideal Decompressor would _not_ try to recreate the original
dynamic range, but rather provide an audio output with very little
dynamic range (8-bit output/DAC would be fine).

I would greatly appreciate any information about such a device or
potential sources of information about such a device.

Thanks,
Al


--

------------------------------------------------------------------------
Al Polivka                       Internet: apolivka@x102a.ess.harris.com
Harris Corporation                   UUCP: uunet!x102a!apolivka
Electronic Systems Sector           phone: 407-729-2983
Melbourne, FL 32902
------------------------------------------------------------------------
From: knuthf@loke.dhhalden.no (KNUT HARALD FINSTAD)
Newsgroups: sci.electronics
Subject: Artificial Intelligence
Date: 9 Apr 92 14:08:43 GMT
Organization: Ostfold College


  My reception for bad times in computer-business: More investments
  in artificial intelligence. 
Newsgroups: sci.electronics
From: nagle@netcom.com (John Nagle)
Subject: Re: Mercury Memory
Date: Thu, 16 Apr 92 06:20:58 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Distribution: usa

hbg6@phx.mcd.mot.com (John Schuch) writes:

>I was watching the PBS program "The Machine That Changed The World"
>last night ( the series deals with the history of computers ).
>They mentioned some sort of data storage device called a mercury
>tank. If I remember correctly it was used in the ENIAC computer
>system. Anybody know what it is or how it works?

      ENIAC didn't have mercury delay lines, just vacuum-tube
registers.  IAS, the Institute for Advanced Study machine designed
by Von Neumann, did, as did one of Turing's post-WWII machines.

      Delay line memory worked by using a mercury tank with a transducer
at each end as an acoustic delay line.  As bits were received at the
receiving end, they were reclocked and their level normalized, then
sent around again at the sending transducer.  The same bit pattern
could thus be recirculated indefinitely (more or less; this technology
was noise-sensitive and temperature dependent.)  As a memory, it
looked like a drum; you had to wait until the desired data came
around to read or replace it.  Inherently slow technology. 

					John Nagle
From: GNR100@psuvm.psu.edu
Newsgroups: sci.electronics
Subject: Problem W/ Pspice5.0
Date: 17 Apr 92 19:49:35 GMT
Organization: Penn State University


   Could somebody please help me out?  I got Pspice5a.zip from
wuarchive.wustl.eduand then downloaded it to a IMB PS2 and then unzipped
it.  But when it got to the file pseve150.001, I got a message that
said there was not enough room on the disk.  But I checked the hard drive,
and there was more than 10 times the needed space.  Is this file needed
for the program?  What happened? How can I fix it?
                Thanks,
                 gnr100@psuvm.psu.edu
   Wuarchive.
From: brianr@tekig1.PEN.TEK.COM (Brian E Rhodefer)
Newsgroups: sci.electronics
Subject: Re: Driving multiplexed LED displays?
Summary: inductive current limiting
Date: 9 Apr 92 03:10:58 GMT
Reply-To: brianr@tekig1.pen.tek.com
Organization: Tektronix, Inc., Beaverton,  OR.

In article <1992Apr5.205643.1@wombat.newcastle.edu.au> eerbl@wombat.newcastle.edu.au writes:
>
> I have 4 seven segment LED displays which I would like to ... multiplex
> these things ... driving them with something like 40mA per segment.
> ... 40mA times 7 adds up to quite a bit of current.
>
>	Can you suggest any good ways to do this?
>

While we're on the topic, I'd like to remind folks of a cute trick
HP used in their old LED-readout pocket calculators, presumably to
extend battery endurance:  inductors as current-limiting elements.
During each digit-display operation, to-be-lit segments are switched
ON only long enough to allow the applied voltage to ramp the segment
currents up to a desired level, and then the drivers are switched OFF.
During the rest of the digit-display cycle, the energy built up in each
inductor drains out into the forward drops of the LED and the catch diode.
Schottky catch diodes would return 75 to 80% of the stored energy to the
LED, but using the on-chip clamp diodes of the driver IC is more convenient,
and should still put 60% of the stored energy back into the LED.  Of course,
the digit rate must be low enough to allow the currents to decay completely.

Obviously, this technique depends even more heavily on the proper behavior
of the CPU; the squeamish should fuse the LED supply (which needn't be
to be regulated; 8 to 20V would be fine), and maybe even place the segment
drive enable timing under control of a nonretriggerable oneshot.

Brian Rhodefer


normally used in muxed displays isn't too much of a concern in the
original poster's
From: michaeln@hpcvnb.CV.HP.COM (Mike_Nason)
Newsgroups: sci.electronics
Subject: Re: Commodore help
Date: 12 Apr 92 08:14:03 GMT
Article-I.D.: hpcvnb.25470001
Organization: Hewlett-Packard Co., Corvallis, Oregon

hi all, 
  after reading the responses the the original post i thoght i'd drop 
my 2 cents worth in.  73 magazine did an article about converting a c64 
to 12 volt operation along with the disc drive. i don't remember what 
month/year it was in, but i have it at home some where and if your still
looking for info drop me a line e-mail. i'll look it up as to month/year
and page numbers for you. if all else fails i could even snailmail you
a copy.  73's mike nason ka7hbb 
Newsgroups: sci.electronics
From: rainer@spot.Colorado.EDU (Rainer Malzbender)
Subject: Re: Tying LSTTL inputs to Vcc?
Organization: University of Colorado, Boulder
Date: Thu, 16 Apr 1992 15:43:45 GMT

In article <dfs.703361967@ro> dfs@doe.carleton.ca (David F. Skoll) writes:
>I'm using some LSTTL parts in a circuit I'm building, and some inputs
>have to be tied to a constant logic "1".
>
>Why in most designs I've seen do people use
>either the resistor or spare gate method?

I always thought the reasoning had to do with current limiting in the event
of a catastrophic failure by the chip containing the pull-up. Without a
resistor you could short out the power supply, although that doesn't seem
to be such a big deal any more. Certainly for home hacking I never use
resistors.

-- 
Rainer Malzbender 
Post-doc, Physics
U. of Colorado, Boulder (303)492-1366              rainer@shelley.colorado.edu
Newsgroups: sci.electronics
From: slice@gagme.chi.il.us (Steve Steiner)
Subject: Re: Pinewood derby finish  (was help. . .)
Organization: Gagme Public Access UNIX, Chicago, Illinois.
Date: Fri, 3 Apr 1992 14:44:38 GMT

In article <69542@ut-emx.uucp> CCEB001@UTXVM.CC.UTEXAS.EDU writes:
>Jorgenson@plains.nodak.edu asks how to determine finish order on a
>six lane pinewood derby track.  I would advise against using such a
>device.  It is usually pretty easy to pick the winners until very
>late in the eliminations.  Also, if you race 6 cars per heat, the
>derby wont last long enough to make it worthwhile to the kids, some
>lanes will be faster than others, and you will spend more time setting
>up heats than racing.
>
>For 2 lanes photo diodes and a dual trace scope would be a quick and
>dirty solution.  I just switched lanes and ran the heat over which
>was adequate to produce a clear winner without electronic aid in all
>but one case.
>
>One pack near us used a camcorder that does slow motion and freeze
>frames.  Point it at the finish line.  A "blimp shot" is effective.
>Monitors for the audience are optional.  If you have a choice
>of camcorders, try them all.  Picture quality varies.  Provide bright
>light to improve picture quality.  This requires no research and
>development on your part and no headscratching by your successor when your
>boy turns 11 and joins the Boy Scouts.  I just (barely :-) lived through
>this so additional non electronic advice can be had by private mail.
>
>Mike.Coyne@utxvm.cc.utexas.edu
>Coyne@utxvm.bitnet

The pack that I'm cubmaster of, has built our own track from scratch.  Its
an eight lane marvel.  It has an electronic finish line, that works on the
principle that the first car through will push a plastic strip connected to
a switch, that will illuminate a light over the lane of the winner.  It
also has the capability to be used as two four lane tracks.  With eighty
boys in the pack, this is a big win.  Our races now last about one and a
half hours.  Down from the two to three.  But the best thing is there is no
arguments about who won the heat or the race.

The track is made from 4 sheets of 4x8 plywood with strips for the cars.
The finish line electronics, sit on a bar suspended over the track. and 2x4
for the legs.

If any one would like more info.  Please e-mail.
-- 
Steve Steiner                                 | Telephone: (708)860-2754 (home)
slice@gagme.chi.il.us                         |            (708)773-5864 (work)
If the elevator to success is out of order... |   Address: 564 Gilbert Drive 
Use the stairs                                |            Wood Dale IL 60191
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: Hex-FET's and infinite im
Date: 11 Apr 92 02:31:31 GMT
X-Maildoor: WaflineMail 1.00r

DS>I just got a car audio amplifier from Coustic.  In the manual, it says it
DS>uses hex-FET's and NOT to turn the amplifier on if there is no load on the
DS>outputs.

DS>I don't know anything about hex-FET's, but it seems unusual that an infinite
DS>output impedance would cause damage to a transistor.  However, I'm always
DS>learning just how much I don't know, so if someone could enlighten me in the
DS>ways of hex-FET's or why this might cause damage, I'd be grateful.

A hex fet is a high power MOSFET.  They work by having a metal
oxide capacitor on the gate of it's internal fet.  Hex fets have
a large surface and have thousand of fets in parallel.  anyhow.
The reason they say this is it may build up a charge on the
internal capacitors that exceed it's dielectric strength and
internal voltage limits.  thus it would SELF destruct.

        STEPHEN CYBERMAN@TOZ.BUFFALO.NY.US
        commiserated at Fri  04-10-1992  17:57:43
---
 * SLMR 2.1a * All ri    ght, leave th    e TAB ke    y ALON    E!
               
Newsgroups: sci.electronics