HDTenEightyP/NetNews huggingface dataset:
From: digdug@iastate.edu (Doug V Tran)
Subject: TEST capacitors
Organization: Iowa State University, Ames IA
Date: Tue, 1 Sep 1992 14:04:42 GMT

How does one go about testing a capacitor without a DMM with a capacitor tester on it.  Let's say I have the following equipment:

	VTVM
	O-scope
	Signal generator
	power supply.

Could someone define what a COUPLING CAPACITOR, AND GRID RESISTOR.  What are
there functions and characteristics.


thanks,
later,
doug

Newsgroups: sci.electronics
From: cavande@lims02.lerc.nasa.gov (MARK VANDERAAR)
Subject: Wanted : Software for Quine-McClusky Algorithm
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA Lewis Research Center
Date: 28 Aug 1992 12:06 EST  

Does anybody have or know where software is available that performs logic
minimization using the Quine-McClusky algorithm (or something similar)?

Thanks,
      Mark
      cavande@lims02.lerc.nasa.gov
From: miked@syscon.rn.com (Mike DeMetz)
Newsgroups: sci.electronics
Subject: Re: Is there 9V size 9V Nicads?
Date: 2 Sep 92 13:12:30 GMT
Distribution: usa
Organization: Syscon Corporate Headquarters - South Bend, IN USA

meric@leland.Stanford.EDU (meric ozcan) writes:

>The 9V size Nicads that I see are 7.2V or 7.5V. However manufacturers
>are smart enough to either not specify the voltage, saying that 9V
>size for 9V equipment, or print the voltage rating with a fine print.
>What I am looking for is 9V size Nicad with a voltage rating as close
>as possible to 9V. Does anyone know if this exist? Thanks.

>Meric
>meric@leland.stanford.edu
Yes. Look for VARTA brand. They are made in Germany and are true 9V
Ni-Cads. I think they are 100mAH.
Newsgroups: sci.electronics
From: blp@cypress.com (Bruce Prickett/PROM)
Subject: Re: How hot can the 486-50 cpu run ?
Summary: Silicon Can Run > 125 C
Organization: Cypress Semiconductor, San Jose, CA
Date: Sat, 29 Aug 1992 00:54:59 GMT
Expires: Mon, 28 Sep 1992 07:00:00 GMT

>I'm sorry but you're talking nonsense.
>Silicon semiconductors have max. chip temperatures of about 75 to 125 deg C.
>I may be wrong, but I think the maximum for the 486-33 is 85 deg C. The case
>temperature depends on the case type (ceramics or plastics) but will always
>be lower, approximately 40 to 60 deg C.

I don't know who was talking nonsense, but: Silicon can run lots hotter
than 125 C at the die. Military chips are spec'ed to work over a range
of -55 to 125 degrees C AMBIENT temperature. Since the thermal resistance
("THETA J-A") from the die to the air can be > 50 degrees C per watt for ceramic
packages, then the die temperature can easily be more than 25 degrees higher than
the ambient if the chip burns just half a watt. Chip temperatures > 150 C
are not uncommon when chips are run at 125C . Plastic packages have a much
higher thermal resistance, and tend to degrade at internal 165 C, so they
are usually limited to the commercial temperature range of 0 - 70 C ambient.

>Anyway, in PC-486's sold today, the max. temperature will be exceeded in most
>cases unless you are using an additional cooling fan *near* the CPU and/or
>an ICECAP or s/t like that.

Sounds like good advice to me. Reliability degrades rapidly when things heat up!

	Bruce Prickett
	blp@cypress.com
Newsgroups: sci.electronics,rec.radio.amateur.misc,rec.aviation
From: jackson@stc.nato.int (Andy Jackson)
Subject: Supplier Wanted for Aircraft Mike Plugs (3/16")
Organization: SHAPE Technical Centre, NL
Date: Thu, 27 Aug 1992 10:22:17 GMT

Does anyone know where I can find a supplier for jack plugs and
sockets for the microphone/push-to-talk of "standard" aircraft headsets?
(By "standard", this includes David Clark headsets, at least!)

As far as I can determine, the plug is 3/16" (about 4.8mm) diameter,
[and 28 or 29 mm long - sorry to mix units!]  - it is NOT 1/4" diameter as
is the headphone plug.  It has 3 or 4 sections (3 are required, 4 will do!).
It is also NOT the short, squat plug used on some headsets and known as
a "NATO" plug.  To my uneducated eye it looks like what was/is known in
the UK as a "Post Office" plug but I don't know the dimensions of that
to be able to check.
 
None of the local electronic shops has these and I haven't found an
aircraft spares shop, either.

I need a couple of line plugs and 6 chassis mounting sockets.  (I'm putting
together a portable intercom for a flying friend.)

Any pointers to suppliers - local or mail order - would be most
gratefully received.  Please post responses if you think there is
sufficient interest, otherwise Email me directly.

Many thanks for any help! - Andy.

-- 
Andy Jackson                                   jackson@stc.nato.int  OR 
SHAPE Technical Centre,                        ...!sun4nl!shapetc!jackson
PO Box 174,
2501 CD  The Hague,
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Re: Complete B&W NTSC timing ???
Date: 2 Sep 1992 08:31:54 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com
Keywords: NTSC,TV,Video,timing

In article <1992Aug31.132411.8008@ms.uky.edu>, billq@ms.uky.edu (Billy Quinn) writes:
> What does one have to do to a composite video signal to make the TV
> do a verticle retrace?  This is for BLACK & WHITE video and it does
> not need to be broadcast quality!  My only referrences to diagrams of   
> this sort are for color video.  It seems that with out color one could
> just keep the horizontal sync low for a while after the last line of 
> video.  Is this true?  If so, how long does it take?  Any suggestions,
> references etc?
> 

Yes, just taking the signal to the sync level (0v) for a couple of line
periods will do it. Its crude, but is done on many of the cheap
computers & TV games.

Within the TV there is usually some sort of integration circuit (a
resistor/capacitor pair). The short sync pulses at the start of each line
don't charge the capacitor up very much, and it discharges before the
next line, so nothing happens. A long pulse at the end of the frame allows
the capacitor to charge up enough to trigger the vertical retrace.

A real broadcast-quality signal uses a series of long pulses, each almost one
full line in duration, over about 10 lines. They are long enough to allow
the integration capacitor to charge, but the fact that there is still a
rise/fall at each line period allows the horizontal circuitry to stay in sync.
In practice a modern TV will stay synched anyway, so just using one
long pulse of 600mS or so will work OK.

Steve
From: dcb0@gte.com (Daniel Bazinet)
Newsgroups: sci.electronics
Subject: Cordless phone technology status ?
Keywords: phone radio transmit recieve AM FM
Date: 31 Aug 92 21:12:21 GMT
Distribution: na
Organization: GTE Laboratories Incorporated, Waltham MA


Hi,
	I am trying to find some info on the latest generation of
	cordless telephones ( not celluar ).  Some of the new
	models I'm seeing pop-up in the stores indicate that they
	have "digi-clear" circuitry or other such "technology".
	  Do they mean that the actual signal format between the
	base-set and the handset is digital ? ( QAM , PSK , or ASK )
	Or is it just some type of filtering done before conventional
	AM or FM transmission.  This brings another querstion ! Do
	cordless phones use AM or FM transmission ?  
	  Any help appreciated.
				Thanks,
				   Dan Bazinet
From: disbrow@gilligan.dfrf.nasa.gov (Jim Disbrow)
Newsgroups: sci.electronics
Subject: PADS software
Keywords: PADS schematics
Date: 28 Aug 92 20:54:45 GMT
Reply-To: disbrow@skipper.dfrf.nasa.gov
Organization: NASA Ames-Dryden FRF, Edwards, CA

I just got the PADS-PCB and PADS-Logic and associated libs off
some FTP site.  Problem is it won't install.  Seems it needs to
be installed from a floppy, but I get an error message something
like "Can't find file, maybe not in your path".  Has anyone had
any similar problems?  It doesn't tell me which file it can't find.
Any help will be much appreciated.

Thanx,
-- 
Jim Disbrow

work: 805/258-3417
home: 805/948-1363

internet:  disbrow@skipper.dfrf.nasa.gov

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
  Brain. Brain. What is brain?
      -- Kara the Eymorg, "Spock's Brain," stardate 5432.3.
Newsgroups: sci.electronics
From: jchapman@polaris.cv.nrao.edu (John Chapman)
Subject: Can 220V 50 Hz Stuff be run on US 220V 60 HZ power  ?
Organization: suomynonA scixelsyD
Distribution: sci
Date: Sun, 30 Aug 1992 07:55:55 GMT

	Some friends of mine came to the US with several 
pieces of equipment from FRANCE. They are all 220 Volt
at 50 HZ. and none of them have switches to set the 
or separate transformer taps. I need to know if I will 
fry their stuff if I plug it up to standard US 220 
volt 60 cycle power ? If anyone can advise me on any/all
of the following and/or suggest the most cost effective 
way to get 50 hz power, I would be MOST appreciative :

1) An Armstrad PC. The power supply for the PC is in the
   display unit and passes DC power to the system unit
   through a cable.  Switching Power supply used to derive
   with very non-standard connectors.
2) A musician's audio power amplifier hand made somewhere in
   France. There is a HUGE transformer to step down the AC and
   it only has the one 220 v primary winding. Probably needs
   250 Watts of power.
3) A cd player with a cheesy little power transformer, that I 
   could replace.
4) A musician's mixing board -- low power consumption but lots
   of little analog circuits.

You can e-mail me or post it your response to this group.
			THANKS.......


--






------------------------------------------------------------------------
| John Chapman                   | " No man stood on truth. They were  |
| jchapman@polaris.cv.nrao.edu   |   merely banded together, as usual  |
|				 |   one leaning on another, and       |
|                                |   altogether on nothing. " -Thoreau | 
------------------------------------------------------------------------
From: ame@matt.ksu.ksu.edu (Abdulrahman M El-Koubysi)
Newsgroups: sci.electronics
Subject: Need to know about appl. that could use EMI shielding
Date: 31 Aug 1992 11:10:11 -0500
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu
Summary: Need to find out about applications that could use EMI shielding
Keywords: EMI, shielding,


I am trying to put together a list of applications that could possibly use
some shield from low frequency electromagnetic interference (EMI). Dose 
anybody out there know of an application that could be improved if shielded from
EMI????


A. R. El-Koubysi          | Internet: ame@matt.ksu.ksu.edu
College of Engineering    | Bitnet  : ame@ksuvm
147, Seaton Hall, KSU     | Phone   : (913) 532-5580 
Manhattan, KS 66506       | Fax     : (913) 532-6944 

Newsgroups: sci.electronics
From: sjm2228@venus.tamu.edu 
Subject: CGA --->  Analog RGB
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Wed, 26 Aug 1992 03:46:00 GMT

Several years ago, I constructed several of these devices which employed
only four transistors, resistors, caps, and diodes.  The design looked
terrible on paper. ( the horizontal sync pulse was rectified and filtered to 
provide a DC power supply for the transistors).   However, the device performed
quite well, was cheap and self-sufficient.  I have lost my schematic
and thus I don't know exactly how the signal matrixing was done.
Does anyone recall this circuit?  Any help will be greatly appreciated.
From: mancus@zaphod.jsc.nasa.gov (Keith Mancus)
Newsgroups: sci.electronics
Subject: Re: Need encoding scheme for TV remote infrared controller
Date: 2 Sep 1992 18:15:47 GMT
Organization: nasa-jsc

In article <BtyE2K.3ts@news.cso.uiuc.edu>, tmkk@uiuc.edu (Khan) writes:
> In article <1992Sep2.003540.24065@aio.jsc.nasa.gov> mancus@roger.jsc.nasa.gov (Keith Mancus) writes:
>>  (1) Is there a standard [IR ]carrier frequency [for TV remotes]?
> There isn't a standard ANYTHING. Many remotes operate on 40kHz IR carrier
> frequencies, but it's far from being a standard.
 
  Sigh.  That's what I was afraid of.

>>The IR sensor we're using detects 40 MHz.
> Unless that was a typo and you really meant 40kHz....
 
  Oops. :-)  The sensor I am using (sorry, I don't have the part # handy)
is supposed to be commonly used in remotes.

>>  (2) Is the encoding scheme standardized?
> Not by a long shot.
 
  Odd.  I've seen "generic" controllers that can be programmed to
drive a wide variety of remote-controlled devices.  It seems pretty
difficult to do this w/out any standards!

> Borrow/obtain an oscilloscope....after playing around a bit,
>you should be able to determine the encoding scheme used, or at the very
>least which patterns go with which....
 
  <groan>  That's just what I was hoping to avoid.  Sigh.

-- 
 Keith Mancus    <mancus@sweetpea.jsc.nasa.gov>                         |
                 N5WVR                                                  |
  "If I owned Texas and I owned Hell, I'd rent out Texas and live       |
  in Hell." -General Sheridan                                           |
From: rbhardin@undergrad.math.waterloo.edu (Ron Harding)
Newsgroups: sci.electronics
Subject: Re: PADS software
Keywords: PADS schematics
Date: 31 Aug 92 17:00:55 GMT
Organization: University of Waterloo

In article <1992Aug28.205445.16138@news.dfrf.nasa.gov> disbrow@skipper.dfrf.nasa.gov writes:
>I just got the PADS-PCB and PADS-Logic and associated libs off
>some FTP site.  Problem is it won't install.  Seems it needs to
>be installed from a floppy, but I get an error message something
>like "Can't find file, maybe not in your path".  Has anyone had
>any similar problems?  It doesn't tell me which file it can't find.
>Any help will be much appreciated.

I had the same problem.  When you unpack the archives, you must use the
option that tells the archiver to create directories.  "-d" or something
like that.  They really should document this better, and they really should
provide a more meaningful error message.

=============================================================================
From a local computer call-in show:	|  Ron Harding
Q: I hear all this talk about base      |  rbharding@descartes.waterloo.edu
   memory, expanded memory, and         +------------------------------------
   extended memory.  What is the difference, and why don't I have them on
   my Amiga?
A: Well, the Amiga doesn't offer you that kind of flexibility...
=============================================================================
Newsgroups: sci.electronics
From: root@drdhh.hanse.de (Bjoern Kriews)
Subject: Stepper Motor Control
Summary: May I drive stepper motors reverse way ?
Keywords: stepper, transistor
Organization: Digital Island
Date: Sun, 30 Aug 1992 23:55:24 GMT

Short question:
I want to drive a fourphase 12V stepper motor from a 5V HCT latch.
Is it possible to use a simple NPN transistor and to connect
the motor common lead to 12V instaed of ground ?

Will the stepper run with reversed coils ?
I'll try out but I'd like to know if I do big big NONO's :-)


Thanks in advance, Bjoern



-- 
bkr@drdhh.hanse.de - Bjoern Kriews - Stormsweg 6 - D-2000 Hamburg 76 - FRG
------------------------------------------------------------------------------
         "Ich trinke auch nicht weniger als andere Leute."  (K.H.)
From: jgd@dixie.com (John De Armond)
Newsgroups: sci.electronics
Subject: Re: What's a good price for a 4 channel 100 MHz analog scope?
Date: 25 Aug 92 22:31:28 GMT
Organization: Dixie Communications Public Access.  The Mouth of the South.

jeff@hpuplca.nsr.hp.com (     Jeff Gruszynski) writes:

>Only HP's high end scope are "DC-to-Daylight" (i.e. 54120 or 547xx) and
>priced appropiately.  The 54600A and 54601A are $2395 and $2895,
>respectively.  Both are 100MHz, Analog-style control, Digital sample and
>trigger.  '00 is 2 channel; '01 is 4 channel.  I'm planning on getting
>one myself, but I'm still torn on the number of channels I want.

Back to the original topic, my advice to the original questioner is
carefully evaluate your need for 100 mhz.  If your needs are more 
modest, particularly if your needs tend more toward the audio end of 
the spectrum, you should seriously consider the Fluke 97 Scope-O-Meter.
It is a 50 mhz dual trace handheld digital storage scope that also
doubles as a very nice large digit DVM.  One of the more useful
aspects for me is it can drive an HP thinkjet or Epson printer directly
so that screen images can be saved for later reference.  At $1795 list,
street price a couple of hundred less, it is a tremendous bang for the 
buck.  Another useful feature is the ability to dump its memory out
the interface which means things like FFT analysis can be run against
the data on a PC>

My original plan was to keep an old Tek 465 for high speed work and 
use the fluke for the rest.  I recently sold the Tek because of non-use.
The Fluke is the single most useful piece of test equipment I've ever bought.

John

-- 
John De Armond, WD4OQC               |Interested in high performance mobility?  
Performance Engineering Magazine (TM) |
Marietta, Ga                         |Interested in high tech and computers? 
jgd@dixie.com                        |Write me about PE Magazine
Need Usenet public Access in Atlanta?  Write Me for info on Dixie.com.
From: david@moe.ece.utexas.edu (david lee)
Newsgroups: sci.electronics
Subject: Resist Pens in Plotters
Date: 26 Aug 92 16:20:36 GMT
Reply-To: david@moe.ece.utexas.edu (david lee)
Organization: The University of Texas

Netfolks:
  I have been using permanent markers in my plotter, writing directly
onto copper pc boards, trying to circumvent the photo-lithographic steps.
This is what I hope to do:

1. Draw the circuit patterns with my favorite software.
2. plot the pattern on paper.
3. Tape a copper clad pc board (no photoresist) over the patterns
    on the paper.
4. replace the plotter pens for paper with a waterproof permanent marker.
5. replot the circuit patterns on the copper.
6. Bake (until done :-) the board at about 60 C for an hour or so
   just to ensure that the ink is "good 'n dry".
7. toss the board in the etching tank.
8. wash/dry/drill/solder/be happy.

Here's the problem. It's not working. I am using the following pen:
The Ultra Fine Point Sharpie (R) by Sanford(R) (color = black).
Well, by the time the copper is etched, the ink is starting to dissolve as
well. This leads to pits, breaks etc. The resist pen from Radio Shack
however is holding up quite well on the same board.
So, why don't I just put the Radio Shack Pen in my plotter?
Because the tip on the Radio Shack Pen does not yield nice, fine traces.
(I need to run a trace between the pads on an IC, for example.)
So, Do you know of a fine tip pen whose ink is as robust as the typical
resist pen?

Best Regards,
please reply directly to

david@moe.ece.utexas.edu

and I will summarize for the net.
From: slwt7@cc.usu.edu
Newsgroups: sci.electronics
Subject: FFT Software wanted
Date: 27 Aug 92 22:30:34 MDT
Organization: Utah State University

I am looking for a FFT program that will do arbitrarily large
input files.  I've looked at FFT142.zip on an anonymous
FTP site and it will only do 4096 or so points.

This software needs to work on a PC.  I have one for UNIX but not
PC.


Brian Wallis
From: bbb@kuhub.cc.ukans.edu
Newsgroups: sci.electronics
Subject: Freq Change of a Pager
Date: 3 Sep 92 13:28:29 CDT
Organization: University of Kansas Academic Computing Services


Is there anyone out there who might be able to give me a hand in
changing the receive freq of a Motorola Page-Boy-II  pager?
Its currently at 464.6mHz and I need to get it to 496.55mHz.
If there is anyone who knows about these units, I'd sure like to 
'chat' with you.  Either by e-mail, or I could phone you.
(Its needed as a telemetry receiver for research being carried out
here at the Univ.)
Many thanks in advance... (let me know if there is a better news group
to ask this of. I'm tring rec.radio too.)  Thanks folks
BB
From: haynes@cats.ucsc.edu (Jim Haynes)
Newsgroups: sci.electronics
Subject: Weird Science?
Date: 31 Aug 92 21:38:19 GMT
Organization: University of California; Santa Cruz
NNTP-Posting-Host: hobbes.ucsc.edu


I've got this circuit which consists of
   8:1000 ohm input transformer feeding
   DIP bridge rectifier feeding
   base-emitter junction of a transistor.
The idea is to connect the 8-ohm input to the output of a radio or
tape recorder and turn on the transistor when there is some signal.

It works fine, at first.  After it sits for a while, turned off, it
won't work.  Then I disconnect one of the secondary leads from the
transformer, observe with an AC voltmeter that there is voltage there,
and reconnect it.  At that point it starts working again.  I've been
through several cycles of this - probably I'll connect the transformer
with a clip lead to make it easy to get it going until I get to the
bottom of it all - but does anybody have a clue what is going on here?
Intermittent connection somewhere down inside the transformer?  Is there
some latchup phenomenon with DIP bridge rectifiers?
-- 
haynes@cats.ucsc.edu
haynes@cats.bitnet

"Any clod can have the facts, but having opinions is an Art."
        Charles McCabe, San Francisco Chronicle
From: jgauvin@ncr-mpd.FtCollins.NCR.COM (jgauvin)
Newsgroups: sci.electronics
Subject: Re: Humidity Sensor Needed (Cheap!!!)
Date: 28 Aug 92 16:14:18 GMT
Reply-To: jgauvin@ncr-mpd.FtCollins.NCR.COM ()
Organization: NCR Microelectronic Products Division

In article <BtKDF8.4G8@cmptrc.lonestar.org> neal@cmptrc.lonestar.org (Neal
Howard) writes:
>Can anyone out there help me with my search for something to use as an
>electronic relative humidity sensor. So far my search has revealed the
>following methods for building a sensor device for use in constructing an
>electronic hygrometer I wish to interface to my PC:

<bunch of stuff deleted>

There are commercially available low cost humidity sensors, but unfortunately
I cannot remember who builds them. It'll come to me some day. I do know this,
however: they are based on a capacitor with an exposed dielectric. As it
absorbs water vapor, its capacitance changes. The response time is very good,
and the humidity range is something like 10% to 90%. A recent issue of
Electronic Design had an applications example for a simple circuit that would
output a 0 to 1 Volt output corresponding to 0% to 100% humidity.

-- 
Jeff Gauvin, Applications Engineer - Graphics Products
NCR Corp., Microelectronic Products Division
1635 Aeroplaza Drive, Colorado Springs, CO 80916
Voice: 719-596-5795, x380    FAX: 719-597-8225
Xref: sparky sci.electronics:15190 alt.guitar:7736
From: jnelson@lonestar.utsa.edu (John P. Nelson)
Newsgroups: sci.electronics,alt.guitar
Subject: Re: Building effects units for guitars
Date: 3 Sep 92 22:27:23 GMT
Organization: University of Texas at San Antonio


     I, too would be very interested in any info on building effects
units..

jnelson@lonestar.utsa.edu
From: galenr@hpgrla.gr.hp.com (Galen Raben)
Newsgroups: sci.electronics
Subject: Re: That Magic TV screen
Date: 27 Aug 92 22:14:52 GMT
Organization: Hewlett-Packard, Greeley, CO

In sci.electronics, aj008@cleveland.Freenet.Edu (Aaron M. Barnes) writes:


>Have any of you seen the 30 minute infomercial for the "Magic TV"?
>The point of the show is to get you to buy a plastic screen which
>you place in front of your 13" TV and the 25" screen magnifies th
>e TV to look like like a 25".
...
>Anyway,might any of you folks out there know what the screen is mad
>e out of?

Sounds like a plastic fresnel (spelling?) lens...
Edmund Scientific used to sell these to hobbyists for making solar
furnaces and homemade overhead projectors...  Can't imagine one of
these being good enough for TV viewing though, unless it's cut very
fine.

You should be able to find these in a local science/educational/nature
store... dunno about cost though.

- Galen -