HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.electronics
Date: Tue, 14 Apr 1992 01:19:54 -0400 
From: Wendell Wayne Lansford <wl1p+@andrew.cmu.edu>
Subject: Tunnel Diode Model Needed

I am posting the following request for a PSpice tunnel diode model for
a friend.  If anyone has such a model, please let me know.

--
Wendell Lansford, INI/CMU
phone:  (412) 621-4108
email:  wl1p+@andrew.cmu.edu
--
---------- Forwarded message begins here ----------

I am looking for a PSpice model for a Tunnel Diode.  I need it to be functional over the full voltage range (I have a model that works (0-2)Volts).

Thanks
From: jfreem@ecsvax.uncecs.edu (Joe Freeman)
Newsgroups: sci.electronics
Subject: CCD Imager or Chinon number
Date: 13 Apr 92 19:57:09 GMT
Distribution: usa
Organization: UNC Educational Computing Service

I saw a Chinon CX-102 camera at a hamfest last month.  It is a CCD
camera in a package about the size of a cigarette pack with a small
focusable lens.  The unit puts out composite video.

Does anyone know of a similar camera wthat puts out digital out?
Or, the number for Chinon America Inc.

Basicly, I want to do some low res frame grabbing in my PC.  It
seems that one of these new low cost, small, camera packs should 
be able to do this for me.

Any help would be appreaciated.  You can reply by email, and I will
sumarize.

<joe>


-- 
Joe Freeman	jfreem@uncecs.edu
		jfreeman@next.com (NeXT Mail)
The opinions espressed here are my own and are not shared by my employer  or
anyone else I know of.  Flames can be mailed to me or routed to /dev/null.
From: Jeff.Lindstrom@ofa123.fidonet.org (Jeff Lindstrom)
Newsgroups: sci.electronics
Subject: MOSFETs and HexFETs
Date: Sat, 11 Apr 92 04:11:18 PDT
Organization: Universal Electronics Inc. (Public access BBS)

TGR>What's the difference between HexFETs and MOSFETs?     

  MOSFETs are low power devices.  HexFETs are designed to control power from somewhat less than a watt to a couple hundred watts.

___
     Amiga MailMan v0.9


--  

Jeff Lindstrom
Internet: Jeff.Lindstrom@ofa123.fidonet.org
Compuserve: >internet:Jeff.Lindstrom@ofa123.fidonet.org
Newsgroups: sci.electronics
From: jw@mck-csc.mckinsey.com (Jeffrey Weiss)
Subject: IR Wired Repeater error correction
Organization: McKinsey & Co., Cambridge Systems Center
Date: Thu, 9 Apr 92 14:55:11 GMT

Sorry folks, I screwed up in the IR remote control repeater schematic.  The
2N3906 should be a 2N3904 (or most any other general purpose NPN transistor).
If you already have a 3906 (or other general purpose PNP), you can use it by
simply reversing the Collector and Emitter connections.  Thanks to
<kennykb@dssv01.crd.ge.com> for pointing this out.
-- 
jw@mckinsey.com (...mit-eddie!mck-csc!jw)              Cogito Ergo Posto
Jeffrey Weiss
Newsgroups: sci.electronics
From: denk@juliet.caltech.edu (Denkewalter, Robert F.)
Subject: Re: DChirping Toy
News-Software: VAX/VMS VNEWS 1.40    
Organization: California Institute of Technology
Date: Fri, 10 Apr 1992 19:02:00 GMT

I  must disagree with thie assumption here.  When I grab
a multimeter in opposite hands, I get on the order of 
1 kohm.  On the same hand, it's much less.  The chirp 
toy is just an oscillator missing a critical resistor
that is provided by your body.  A Radio Snack 150-in-1
kit with all those springs you stick wires into has
plans for something very similar to this.
---Robert
From: witt@iccgcc.decnet.ab.com
Newsgroups: sci.electronics
Subject: Need Twist-Lok Filter Caps
Date: 7 Apr 92 16:44:51 GMT
Article-I.D.: iccgcc.1992Apr7.114451.7750

Hello,

   Does anyone out there know of a distributer that carrys the old
Twist-Lok type of electrolytic capacitors? I'm going to be restoring
some old radios this summer and they all need new filter capacitors,
the dual and triple type, 40/40 at 400v or 30/30/30 at 400v,etc.

   Places like Newark and Allied don't carry these types anymore. I'd
prefer new capacitors but surplus ones will do as long as they're good.
Anybody got any sources that I might try? Thanks.


                                                   Tom Witt
                                                   Allen-Bradley Co.
                                                   Twinsburg,Ohio
From: optimus@max.u.washington.edu
Newsgroups: sci.electronics
Subject: BarCode Reader project ... please help us!
Date: 16 Apr 92 06:06:34 GMT

Hello,
By any chance does anyone in NET world know anything about
BarCode Readers?                                                      
For a class project, we have decide to build a barcode reader as
our project. However we are unfamiliar with the various component
parts (barcode chips, processors, etc) that are on the market that
we can purchase and incorporate in our design. We are hoping to
find a chip that will do the filtering and conversion of the raw
barcode data read by the wand and output the values in ascii form on
data lines (much like those infrared decoder chips that you can  
readily buy to read infrared signals from remote controllers).
We are not sure if similar chips exist for barcode readers. But it
is our sincerely hope that they do.... our grades depends on them. :)

Consequently, we would very much appreciated your help interms of
information about the parts (intergrated chips, barcode processor chips,
etc) that are available for us to purchase and the sources that we
can order them from.
We are interested in the parts down to the component level. We are     
trying to stay alway if possible to already built subunits. One of the
criteria of the project is that most of the soldering are to be done by    
us.

Sincerely,
Scott K. Stephen
scott@max.u.washington.edu
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.electronics
Subject: Re: Metal film resistors and lower distortion
Date: 8 Apr 92 07:50:59 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <1992Apr4.201050.21314@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (Neil Gandler) writes:
>
>I have heard that using metal film resistors in an audio power amp design
>give better s/n ratios and lower distortion than carbon film resistors.
>Is this true or just a myth. This is regarding using a power amp I.C.
>not using individual transistors.

In a *power* amp design, the effect is negligble. In a *preamp* there
is (or was) some truth to this. *Bulk* carbon resistors were often much
noisier than metal film resistors. Newer carbon *film* resistors generally
are about as good as metal film resistors for fixed values. In *pots* the
construction still makes a difference, with the carbon types prone to be
noisier than the others.

Pots in general are enough of a problem that their use is avoided whenever
possible in professional gear. The step attenuator is still a mainstay of
professional equipment.

Gary
Newsgroups: sci.electronics
From: comptec91055@camins.camosun.bc.ca
Subject: hlp network card id routine
Organization: Camosun College
Date: Wed, 15 Apr 1992 03:29:45 GMT



		Hello Hardware gurus and programmers:

			I am attempting to write a small routine which can be
executed on any pc that returns information on the resident network card (type
mem. cap. etc.)  (assembly/c routine).. My problem is that I am unsure of which
interrupts the card takes over when it is installed, whether or not these inter-
rupts are from the dos vector table or directly from the cpu, and how they can
be used to access card info.  If anyone has the time I would very much appreciate
 any information that could be provided.  I will send anyone that responds a copy
of the final program which does a series of hardware checks and verifications
on the pc, including nice output (not that anyone responding would need this,
but what the heck..)   If there are any ideas could you please e-mail them.
 			Thanks in advance,
	
			D. Rozee
From: louis@tronix.SignalPath.on.ca (Louis Bertrand)
Subject: Re: Hex-FET's and infinite impedance
Newsgroups: sci.electronics
Date: 12 Apr 92 02:58:20 GMT
Distribution: world
Organization: Signal Path Designs

dshipley@cs.umr.edu (Dan Shipley) writes:
> 
> I just got a car audio amplifier from Coustic.  In the manual, it says it  
> uses hex-FET's and NOT to turn the amplifier on if there is no load on the  
> outputs.
> 
> I don't know anything about hex-FET's, but it seems unusual that an infinite  
> output impedance would cause damage to a transistor.  However, I'm always  
> learning just how much I don't know, so if someone could enlighten me in the  
> ways of hex-FET's or why this might cause damage, I'd be grateful.
> 

Where are the HEXFETs used?  They could be in the DC-DC converter
or the audio amplifier section.

If they are in the audio section, your amplifier has an oscillation 
problem at light loads and uses the speaker and wiring as an aid 
to stability (sorta like a crutch).  
If they are in the DC-DC converter, and it is not regulated, the drain
voltages would soar to damaging levels with no load.  Just a guess, as
I don't know much about the Coustic amps.  (I thought they just made
decks and crossovers...)

Have fun!
 -- Louis
--
Louis Bertrand   *   Lynden, Ontario, Canada   *   (416) 648-8066
Signal Path Designs (Analog - Digital - Audio - Embedded uCs)
louis@SignalPath.on.ca (new -- may not work yet)
louis%tronix@maccs.dcss.mcmaster.ca (old -- still works fine)
From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Driving multiplexed LED displays?
Date: 8 Apr 92 00:02:50 GMT
Article-I.D.: u.1992Apr8.000250.10627
Organization: University of Washington, Seattle

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 drive
>from a microcontroller (8749H). The problem is that to multiplex these things
>requires driving them with something like 40mA per segment. The humble
>4511 latch/decoder/driver just wont drive this level of current. Also,
>multiplexing requires some form of switch to turn on each display in turn.
>40mA times 7 adds up to quite a bit of current.

	First, have you shaded and filtered the display?  Proper use
of red gelatine filter material might be enough to get the current
down to 20 mA, which the 4511 CAN handle.  Legibility is not
dominated by BRIGHTNESS, but by CONTRAST.  A slightly pricier
option is to put a circular polarizer on the display as well
as a red filter.  

	Second, have you considered using smaller LED displays?  
The needed current to make a legible 1/4" display is quite a bit 
less than for a 1" behemoth.

	Third: since the 4511 includes a latch, you don't need to
multiplex; just use four 4511's and run four different latch enable
outputs from your 8749.  This gets you a bonus, in the form of
reduced RF and power supply glitching, and eliminates the odd
'strobing' effect sometimes visible on multiplexed displays.
This would eliminate the need for a real-time service routine
in your 8749, as well.

	Fourth: since the decoding into seven segments is trivial
for your microprocessor to do, consider using a dumber driver
(as others have suggested); this is likely to require using a
common anode display, while the '4511 is intended for common
cathode displays.

	Fifth: buy a smarter driver, one that can multiplex
and drive the display without assistance (this means that 
your microprocessor won't have to wake up and service the
multiplexing routine at millisecond intervals).  74C926
is such a CMOS counter chip; four wires is all that is required
to interface it to your micro (but beware; you have to
send it a clock pulse to increment the number... so
changing the output from 9999 to 9998 requires clearing
it, then sending 9998 clock pulses).  There are LCD 
versions, too: for circa $20 you can buy a six-digit LCD
counter module that does the same sort of thing: Sub-Cub
from Red Lion Controls (sold by Digi-Key).


	John Whitmore
From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Power Strip Surge Suppressors/EMI filters
Date: 6 Apr 92 20:29:03 GMT
Organization: University of Washington, Seattle

In article <1992Apr2.191022.3208@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>In article <1992Mar30.202612.12237@u.washington.edu> whit@milton.u.washington.edu (John Whitmore) writes:

	<about the value of transient protectors on phone lines>
>>	Telephone equipment is compatible with the same technology
>>(1935 vintage) that had heavy transformers and low surge sensitivity
>>in the old days, and anything authorized to clip into the phone
>>wiring (in the US) is already adequately protected. 

>I certainly disagree with this. In the days when Western Electric built
>the phones used by Ma Bell, this was true. The model 300 and 500 sets
>were better than the telephone wires at withstanding surges and lightning
>strikes. This is no longer the case. Current generation phone equipment,
>and computer modems, can become silicon scrap after a lightning hit on
>the lines blocks away from your location.

	There is NO silicon connected to the telephone wires in an
approved telephone device.  That surge has to get through a transformer
to get to the 'sensitive electronics', and any reasonable care taken
with the transformer can absorb most of the surge right in the
iron (which is really hard to burn up).  There seems to be a lot
of anecdotal evidence that modems/faxes and the like are sensitive
to phone-line surges, which means (IMHO) that there are a lot
of incompetent designers making telephone-connect equipment.
It's true, the FCC requirement is only that the surge won't
cause a hazard to the phone wires or the consumer, and will
cheerfully allow the modem to immolate itself...

	I'm still not sold on phoneline surge arrestors, because
they can be leaky enough to stop a phone from ringing... but if
you're in a lightning-prone area, go ahead and try the surge
limiter.  


	John Whitmore
From: rdi@cci632.cci.com (Rick Inzero)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 7 Apr 92 14:15:50 GMT
Reply-To: rdi@ccird3.UUCP (Rick Inzero)
Distribution: na
Organization: CCI, Communications Systems Division, Rochester, NY

In article <9204050203.AA29602@cmr.ncsl.nist.gov> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
>The arc is established at the base of the "rabbit ears", because that's where
>the two wires are closest. Convective currents caused by the heating of the
>arc cause the air to move upward, drawing the arc with it (once established,
>a lower voltage is required). Eventually, it reaches the top, and "blows out",
>so a new arc starts at the bottom. If it's not shaped quite right, the arc
>will get "stuck" at some point. DO NOT adjust the wires with the power on!!!

Another, slightly more technical, explanation:

When you first plug it in, the air in between the two "L" shaped 
electrodes starts to ionize.  Quickly, it reaches a point where the
ionization is great enough to conduct electricity, and an arc jumps 
between the electrodes, at the point of least resistance (the bottom 
of the "V").  Note the arc heats up the air.  The heat also ionizes 
more air, just above the existing arc, since heat rises.  The arc follows 
the path of least resistance, which is at this point slightly above the 
present arc, so the arc rises up the "V".  This continues until the 
arc reaches the top, where it bows up (still rising due to hot 
air/following path of least resistance).  The arc persists at the top 
until its resistance becomes greater than that at the bottom of
the "V", then it disappears from the top, and reappears at the bottom,
since that is now the path of least resistance.


Other tidbits I've gathered enroute to building my own J. Ladder:

The voltage is what matters, not the current; you need big voltage
in order to be able to arc across an initial 1/2-3/4" air gap.  

Note that there exist some big neon sign transformers.  Mine
is rated 15,000 volts at *3000* ma.  This most certainly would
do some damage if you or I were to touch it while "live".

I've noted that the weather influences the characteristics
and formation of the spark; you may have to readjust the "V" for
changing humidity.
 
Fun things to do with the spark:  
	- you can catch paper on fire, or more impressive, 
		pass a 3x5 card through the spark a few times,
		without catching it on fire, and hold it up to
		the light.  You'll see hundreds of TINY pinholes
		in the card.  This is really neat.
	- with a slow-climing arc, you can sometimes "push it" back down 
		the ladder with the file card

Have fun, but be careful; this kind of stuff could HURT!

---
Rick Inzero				        rochester!cci632!rdi
Computer Consoles Inc. (CCI)			uunet!ccicpg!cci632!rdi
Rochester, NY					rdi@cci.com


"Your grandmother never, ever called me stupid.  
	She always called me 'pinhead'." -Jimmy Stewart in 1988 Campbells Soup
								commercial.
								
Newsgroups: sci.electronics
From: hess@cbnewsf.cb.att.com (michael.k.hess)
Subject: Re: HV shocks (was: Jacob's ladder)
Organization: AT&T
Date: Tue, 14 Apr 1992 12:18:07 GMT

In article <1992Apr14.025731.4589@aero.org> helfman@aero.org (Robert S. Helfman) writes:
>In article <1992Apr13.063137.18999@u.washington.edu> pollock@milton.u.washington.edu (Joe Pollock) writes:
>>In article <1992Apr12.140143.420@cmkrnl.com> jeh@cmkrnl.com writes:
>>>
>>BTW - I found out about all of this the hard way.  I was in the eight or
>>ninth grade, and messing around with a sign transformer in the basement.
>
>Funny, I was exactly the same age when I got my first (and last) shock from
>a sign transformer. I was at a junior high carnival and I set up a

I guess that age 13 and the 9th grade is the time in our lives when we decide
to A)build a jacobs ladder, and B)take a jolt from our creation.
Same story here! 9th grade science project, an oil burner xformer putting out
10Kv@24ma. I thought it was powered down and grabbed the two coat hanger wires
I was using as the ladder (one wire in the left hand, one in the right) Im
just glad that they pulled off the terminals as I rolled up in the tightest
little ball of a fetal position on the floor. The worst shock I have ever
had. But, it taught me to always be extra sure that something is powered down
before you touch (came in real handy when I was working on 100Kw bdcast
xmtrs!!).

Mike Hess
AT&T Bell Labs
Middletown, NJ. USA
From: henze@aludra.usc.edu (William Henze)
Newsgroups: sci.electronics
Subject: Pager info desired
Date: 15 Apr 1992 16:05:31 -0700
Organization: University of Southern California, Los Angeles, CA
NNTP-Posting-Host: aludra.usc.edu

I'm looking for general information on pagers.  I would appreciate
it if someone could tell where I could find sources of information,
perhaps in some magazine or journal article.  I'm looking for all
types of info, ranging from detailed technical info to a general
overview.  Right now I know practically nothing about them beyond
their very basic function.  

Thanks a lot for any help.

Bill Henze

henze@aludra.usc.edu 
or
henze@desperado.etdesg.trw.com
Xref: sparky sci.electronics:8194 rec.music.cd:3891 rec.audio:7097
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.electronics,rec.music.cd,rec.audio
Subject: Re: requesting CD player advice
Date: 8 Apr 92 09:19:44 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <WOOD.92Apr6123829@wood.uk.tele.nokia.fi> wood@uk.tele.nokia.fi (Peter Wood) writes:
>In article <1992Mar26.200842.20858@ncsu.edu>, brian@pysgjb.physics.ncsu.edu (Brian Davidson) writes:
>>>  
>>truth is, there's no difference in the sound quality when you're buying
>>different CD players (as long as harmonic distortion's below .03% but few even
>>need that). what you should look for is the best features and the best warranty
>>for your lowest price
>
>RUBBISH!  Complete Rubbish!  
>
>Go and listen to a few CD players.  If you listen through any half decent amp
>and speakers you will find large differences between the sound of players.
>
>Use your ears, not the specifications.  Technically authoritative posters on
>this net (and I mean people like Dr Max and JJ, not amateurs like me) have
>posted at length on the uselessness of currently published performance data
>for evaluating equipment sound.
>
>Some respondents have claimed that because any loudspeaker is so much 'worse'
>than a CD player (and I'd love to see him/her explain precisely what _that_ is
>supposed to mean) even if there might possibly be differences between CD
>players you'll never hear them.  This is arrant nonsense.

The typical loudspeaker generates between 4 and 7% distortion. A CD player
at .03% distortion is at least 200 times better. If you can tell differences
of 1/200th in distortion, you qualify as one of the golden eared.

>[And if you really want to hear _music_, go and listen to a high-end
>turntable, but that's another story :-) ].

To quote you, 
RUBBISH!  Complete Rubbish!  

No vinyl recording even approaches the fidelity or dynamic range of a CD.

Gary
From: gkwan@balboa.eng.uci.edu (Greg Kwan)
Subject: Re: Source for National LM-2002
Newsgroups: sci.electronics
Organization: University of California, Irvine
Date: 17 Apr 92 01:54:16 GMT

In article <31718@sdcc12.ucsd.edu> dmackie@sdcc13.ucsd.edu (Dave Mackie) writes:
>As the subject says: I need a source for LM-2002's (either  T or AT)
>These are 8 watt audio amplifiers, 5 pin TO-220 configuration.
>
>Mail order is fine.
>Quantity small (less than 10).

Unicorn Electronics has 'em (LM2002T) listed in their latest catalog for:
$0.79 for qty 1-24, $0.75 qty 25-99, and $0.68 for 100+.

Unicorn Electronics
10010 Canoga Ave., Unit B-8
Chatsworth, CA  91311

order line: (800) 824-3432
tech support and info: (818) 341-8833
Hours: M-F, 9-6; Sa, 10-3 PST

$15 min order, n/c for shipping for pre-paid/credit card orders.

I have no connection with them (other than spending lots 'o my money there).


greg

gkwan@balboa.eng.uci.edu
From: pdejong@fwi.uva.nl (Paul Gerard de Jong)
Newsgroups: sci.electronics
Subject: Re: How to ease drop on cord-less phones.
Date: 8 Apr 92 06:33:15 GMT
Organization: FWI, University of Amsterdam

EAVES DROP !!!!

Don't ask me why, I speak Dutch.  :-)

Bart
From: nustad@lightning.med.ge.com (Tim Nustad  x7-4361)
Newsgroups: sci.electronics
Subject: Re: How do I access the parallel port? IIC bus problem
Summary: Additional I2C Documentation
Date: 6 Apr 92 15:06:19 GMT
Organization: G.E. Medical Systems - Ultrasound




The Phillips data sheet for the PCD8584 contains a complete
register description for the chip.  It does not contain
any notes on how to actually use the chip and it talks
just briefly about chip modes, etc.

You may want to request some additional information from 
Phillips:
        
        * "PCD8584; I2C Bus Contoller IC Software 
           Flowcharts" - Phillips Telcom ICs
           Newsletter #7, Feb 92.

        * Phillips will also send you some code
          fragements, mostly 8051 assembler, if
          you ask nicely.



--
==============================================================
   
   Opinions are, of course, my own and not GE's

   Tim Nustad - nustad@mrsvr.ge.com

===============================================================
From: mm@mentor.cc.purdue.edu (Mike MacKenzie)
Newsgroups: sci.electronics
Subject: Re: Color monitor problems; got a magnet near it by accident.
Summary: Soldering guns makes good degausser
Date: 13 Apr 92 15:27:35 GMT
Article-I.D.: mentor.45111
Organization: Purdue University

A weller transformer type soldering guns makes a fair degausser.  Just
remember to turn it on, move it toward the object to be degausssed,
then move it away before turning it off.


Michael MacKenzie	(Purdue University Unix Group)
mm@mentor.cc.purdue.edu