HDTenEightyP/NetNews huggingface dataset:
From: bill@hacktic.nl (Bill Squire)
Newsgroups: sci.electronics
Subject: Re: Help needed: Resistor S.O.T.
Date: 8 Apr 92 22:22:41 GMT


        How about 1.0k?  The back porch of PAL is about 6.5uS and 1k/10nF
would do that.  The burst is 1/2 that time, about so maybe its 510ohms.
Can't really tell by the info given.

                                                Bill
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: How much protection do I need?
Date: 13 Apr 92 04:31:21 GMT
Organization: University of Georgia, Athens

I have had no trouble using 7805-type voltage regulator chips as the
only thing between the automotive 12V line and the device I wanted to
power.  Well, maybe put an RF choke ahead of it too...

By the way, most of the ripple in the 12V line comes from the spark
plugs firing.  The _interesting_ way to do a tachometer would be to
measure the ripple itself, thereby avoiding any connection to the engine.

-- 
==========================================================================
Michael A. Covington, Ph.D. |  mcovingt@uga.cc.uga.edu  |  ham radio N4TMI
Artificial Intelligence Programs | U of Georgia | Athens, GA 30602  U.S.A.
==========================================================================
From: Jeff.Lindstrom@ofa123.fidonet.org (Jeff Lindstrom)
Newsgroups: sci.electronics
Subject: Class "A" Amplifier
Date: Sat, 11 Apr 92 04:11:16 PDT
Organization: Universal Electronics Inc. (Public access BBS)

U>I am a beginner in this field. I heard that Class "A" 
U>amplifier is the best.

  Class A is `best' for low distortion.  However, it also causes the highest quiescent power dissipation.  To reduce power usage, there have been several techniques.
  Class B has two transistors, each controlling the positive and negative swings, but has bad crossover distortion.
  Class AB blends the two by having each transistor work into the other's region a little bit to compensate for the non-linearities as the other transistor is turning on.  It is the most common because of its combination of low distortion and low quiescent power dissipation.
  There are other classes of operation (one used Class A for small power and kicked in higher power transistors only at higher levels).
  Of course, there are different types of output devices that have different `kinds' of distortion.  Golden Ears audiophiles prefer electron tubes with `softer' distortion (which require transformers) and Power FETs, which have similar distortion to Tubes but don't require transformers.

___
     Amiga MailMan v0.9


--  

Jeff Lindstrom
Internet: Jeff.Lindstrom@ofa123.fidonet.org
Compuserve: >internet:Jeff.Lindstrom@ofa123.fidonet.org
From: dmturne@ptsfa.PacBell.COM (Dave Turner)
Newsgroups: sci.electronics
Subject: Re: Dick Smith Electronics
Date: 16 Apr 92 16:42:02 GMT
Reply-To: dmturne@PacBell.COM (Dave Turner)
Organization: Pacific * Bell, San Ramon, CA

In article <1992Apr12.194309.39284@kuhub.cc.ukans.edu> 2frlclover@kuhub.cc.ukans.edu writes:
>Does anyone know if Dick Smith Electronics still exist ?

The last DSE catalog I have is from 1989 (catalog 89C).
Their address then was:


Dick Smith Electronics USA
P.O Box 468
Greenwood, Indiana 46142

(317) 888-7265
(317) 888-7368 FAX

-- 
Dave Turner	(510) 823-2001	{att,bellcore,sun,ames,decwrl}!pacbell!dmturne
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.electronics
Subject: Re: What's the correct cable for cable TV and baseband video?
Date: 11 Apr 92 16:51:12 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <1992Apr7.211551.942@pictel.com> wpns@pictel.com (Willie Smith) writes:
>In article <1992Apr2.183611.2614@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>>In article <1992Mar30.151226.1035@eng.umd.edu> naiming@eng.umd.edu (Naiming Shen) writes:
>>>
>>>I want to install wires for cable TV and maybe used for baseband video
>>>signal also.
>>
>>RG59 is 75 ohm cable for baseband video and CATV RF uses.
>
>Umm, well, sort of.  CATV cable needs to have a full shield (foil is
>good) for leakage considerations, and the frequency response should be
>'good' from around 50 MHz to 500 MHz.  RG-6 is generally used.  RG-59
>is not reccomended due to lack of shielding.

RG-59 is a much abused label. At one time it was a military designator
with a mil-spec, but not anymore. There are lots of RG-59 *type* cables
available, some with belfoil shields, some without. Braid only shield
coverage of 95 percent is available as is cable with only 70% shielding.
Sticking to Belden cables is your best bet for quality cable.

>Baseband video needs to have a low DC resistance and a good frequency
>response from 15 KHz to (something like) 5-10 MHz.  RG-59 is generally
>used, though Belden 8281/9231 is reccomended for 'professional' use,
>like studio wiring.  RG-6 tends to have a relatively high DCR, and is
>not reccomended for use with baseband video.

Baseband is from 30 Hz to 6 Mhz and needs as flat a response as possible
with minimum group delay. We use equalizers on long runs of cable, but
try to choose a low loss cable because the equalizers always disturb
group delay characteristics. Time distortion of the video signal is
a much more serious problem than mere attenuation.

Our professional plants use Belden 8241, one of Belden's versions of RG-59,
for video wiring. We only use 8281 on runs that pass near sources 
of electrical noise. 8281 has double braid shielding, is larger and
much stiffer than RG59, and has more capacitance per foot so it requires
more cable equalization for long runs.

>To throw some more confusion into the discussion, BNC connectors for
>8281/9231 are difficult to come by, unless you want to spend big bucks
>for a crimp tool....  I'm going to have to wire our new house sometime
>Real Soon Now, but I'm not sure _what_ to do....

If you want to play with 8281, you've got to grit your teeth and pay
the $270 for the Kings crimp tool. We use Kings connectors exclusively
on all our coax at our plants. It is by far the most reliable connector
on the market.

Gary
From: kls30@duts.ccc.amdahl.com (Kent L Shephard)
Newsgroups: sci.electronics
Subject: Re: Software request
Date: 14 Apr 92 19:25:24 GMT
Reply-To: kls30@DUTS.ccc.amdahl.com
Distribution: usa
Organization: Amdahl Corporation, Sunnyvale CA

In article <1992Apr14.162435.12865@uwm.edu> alanchem@csd4.csd.uwm.edu (Alan Scott Olson) writes:
>I'm looking for some public domain software for a PC that will allow me
>to draw a circuit schematic and the print it on an HP LaserJet laser printer.
>
>Does anyone out there have or know where I can get a copy of such a program?
>

Pads Software Inc., formerly CAD Software is offering fully functional
versions of its PADS-PCB and PADS-LOGIC software.

They will allow you to enter a schematic design route a board and
print it.  The documentation is okay, but not great.   It does come
with a user manual.  It only works on 286 and above.
Call Mark Pavitt (508)486-9521 and tell them you would like the shareware
evaluation copy of their software.  If you would like ongoing support
for the shareware it costs $50.
--
/*  -The opinions expressed are my own, not my employers.    */
/*      For I can only express my own opinions.              */
/*                                                           */
/*   Kent L. Shephard  : email - kls30@DUTS.ccc.amdahl.com   */
From: spikes@hpscit.sc.hp.com (Bill Spikes)
Date: Thu, 9 Apr 1992 17:04:04 GMT
Subject: Re: DC Shock
Organization: Hewlett-Packard, Santa Clara, CA
Newsgroups: sci.electronics

My mailer doesn't know your host.

How 'bout a low freq audio (two xstr) osc that drives a small 8 ohm to 1-5K
ohm speaker xfmr? Actually, with one cmos gate ic, you can get a gated osc
that is freq and gate time adjustable. Then go through a couple of xstrs to
the xfmr. After you have found the right combination of on-time and freq,
hardwire a simple xstr circuit that gives that best values. Protect the
driver stuff with diodes, also across the battery to keep the HV out of it.
Try to power this thing w/9volt batteries, its gotta be less expensive.

Ah, the brain IS alive today...another idea for ya. You might want to measure
what voltages are generated in battery powered flourscent lanterns.
Those guys must have start up pulses that are mean. I know they have tiny
transformers in them. Maybe the circuit from a photographic "strobe" (flash). 

Did this give ya any ideas?
Sometimes a devious mind IS useful!

Bill
WB6RZG
From: berger@atropa (Mike Berger)
Newsgroups: sci.electronics
Subject: Re: DC Shock
Date: 13 Apr 92 21:16:42 GMT
Article-I.D.: ux1.1992Apr13.211642.22875
Organization: University of Illinois at Urbana

pollock@milton.u.washington.edu (Joe Pollock) writes:
>For those of you unfamiliar with the "Invisible Fence(tm)" system, the
>owner doesn't just strap on a shock collar and turn the dog loose in
>the yard.  The collar  is a receiver sensitive to pulsed currents sent
>through a wire loop at the perimeter of the yard.  The collar beeps
>about six feet from the wire, and does not deliver a shock until the
>animal is about three feet from the wire.

>There is an extensive training regime the owner must  put the animal
>through: it involves a white cord inside the perimeter to mark it for
>the animal, and several weeks of training, where the owner walks the
>dog near the wire on a lead and issues appropriate commands.  The goal
>is to train the dog to the perimeter and to the beep, not to the shock.
*----
I contend that if you go to all the trouble this training regimen
requires, then you don't need the shock in the first place.


>My experience with this has been with a friend's dogs, which I occasionally
>care for when he vacations, etc.  The dogs have absolutely no apparent
>adversion to the collars.  They will stay inside the perimeter even if
>the fence is off (we had an awful time finding a break in the 1500' of
>wire one week - I finally built an audio detector to trace the loop), 
>and know that if they are not wearing the collars it's OK to cross
>the perimeter.  Yet, even if they are chasing a ball, they halt before
>the collar even beeps.  The training is the key to the process -
>the dogs will otherwise learn to make a running leap.
*----
My experience is with dogs belonging to my parents' neighbor.  They
frequently run right past the "invisible barrier" and then can't get
back in without getting shocked (so they play in the street until
somebody gets them).
--
	Mike Berger
	Department of Statistics, University of Illinois
	AT&TNET     217-244-6067
	Internet    berger@atropa.stat.uiuc.edu
From: afpauls@lims01.lerc.nasa.gov (PAUL SCHWARTZ)
Newsgroups: sci.electronics
Subject: Re: *** Thermal sensor needed.
Date: 9 Apr 92 20:42:00 GMT
Article-I.D.: lims01.9APR199215422283
Organization: NASA Lewis Research Center
News-Software: VAX/VMS VNEWS 1.41

In article <1992Apr2.021633.1@woods.ulowell.edu>, donohuej@woods.ulowell.edu writes...
> 
>	I am a hang glider pilot and would like to design an instrument
>that locates thermals (rising hot air bubbles).  I have though of using
>fast temperature sensors, one on each wing tip, and letting software
>interpret the data in real time and recomend a left or right turn.  Can this 
>be done with infra-red or any other means?  The temp difference is only a 
>few degrees at best.  It must be light weight, run on batteries, and cost 
>less than $200 if possible. An imaging system that would let you visualy
>find thermals would be ideal but I don't think it is possible with the above
>restrictions. 

Infrared imaging doesd not work at temperatures close to ambeint (it 
also is very expensive).  Temperature sensors on the wing tips may work.  
My suggestion is to install thermocouples on each wing and connect the in 
opposition (reverse series) so the two minus leads on the thermocouples 
are connected together.  The voltage across the two positive leads would be 
proprotional to the temperature difference between the wing tips.  The 
polarity would indicate which wing is warmer.  A high gain amplifier driving 
a analog meter might work very well.  The only thing I'm not sure about is
if the thremocouples would respond fast enough to temperatures to make the 
system useful.
Xref: sparky sci.electronics:8537 rec.video.satellite:2167
Newsgroups: sci.electronics,rec.video.satellite
Subject: Help with Zone plate microwave antennas
From: geoffrey@cosc.canterbury.ac.nz (Geoff Thomas)
Date: 15 Apr 92 16:44:27 +1200
Distribution: world
Organization: Computer Science,University of Canterbury,New Zealand


Hi. I'm after some info on construction of a Zone plate microwave
antenna. These have been in use for a while in the UK as Direct
Broadcast satellite antennas, for satellites such as Astra, etc.

I know it has something to do with diffraction, but I'd like to
know more about them. I wish to build a few operating on different
frequencies, and make them as effecient as poss.

Any help much appreciated.

Thanks in advance,


Geoff.
From: jonker@amc.uva.nl
Newsgroups: sci.electronics
Subject: Pointer wanted to Photometrics USA
Date: 14 Apr 92 14:19:06 GMT
Organization: Central computer department

Hello Netland,
does anyone outthere have a pointer (telephone number or
exact address, fax or whatever) to Photometrics LTD,
Tucson Arizona USA? Nobody around here has heared from
them. I know you can do better! Please reply by e-mail to
jonker@amc.uva.nl
thanks,
ard
From: ehare%arrlhq.UUCP@uhasun.hartford.edu (Ed Hare KA1CV)
Newsgroups: sci.electronics
Subject: Re: Need help with Sony TV remote control
Date: 13 Apr 1992 20:06:17 GMT
Organization: American Radio Relay League

In sci.electronics, ldstern@rodan.acs.syr.edu (Larry Stern) writes:

>To all: a neighbor of mine has a 6-7 year old Sony Trinitron, which works
>well except for the remote control. The remote had an intermittent problem
>where it would work fine for a few weeks, not work at all for a few days,
>start working ok again, etc. It seems it is now, finally, dead. There is
>one IC, a crystal, a few resistors and caps, and an LED inside. My question
>is, what usually goes? Is this worth fixing? And finally, can this LED be
>tested with an ohmeter like a "regular" diode?

Larry,

I don't want to state the obvious, but I certainly would double check the
battery. The intermittant nature makes me a bit suspicious.

After that, give it a real close visual inspection. These things are dropped
often and hairline cracks in the pc board or loose solder joints can
cause intermittant problems. The LED can be tested normally, but I woould
imagine that the "diode" could test okay even if it were not emitting light.
Also take a look at and measure the resistor in series with the LED. Some of
them were under-rated in some remote control units. This can result in an
open or high-value resistor and poor or no operation.

I have used an ECG replacement sucessfully in a defective remote control.
You should also keep in mind that the problem could be in the receive 
circuitry in the TV.

Good luck, 73, Ed.

-----
Ed Hare, KA1CV                  | ehare%arrlhq.UUCP@uhasun.hartford.edu
American Radio Relay League     | uhasun!arrlhq!ehare
225 Main St.                    |
Newington, CT  06111            | There is no limit to what you can 
(203) 666-1541 - voice          | accomplish if you don't care who
Senior ARRL Laboratory Engineer | gets the credit. - Harry S.Truman
RFI, xmtr and rcvr testing      |  
-----
From: rg@kunikpok.UUCP (r.g.)
Newsgroups: sci.electronics
Subject: Re: Twist Lock Caps
Date: Tue, 07 Apr 92 07:44:12 CDT
Organization: Kunikpok Kennels & Komputers

For high voltage twist lock caps, try the capacitor companies, particularly
Mallory, directly to find a distributor that can order them for you. At le
st last year, Mallory still made multisection caps at high voltages. I got 
them from my local Newark office, but they had to order them from Mallory.
They were in a slow spot and were VERY helpful. Like all services, your
mileage may vary.

rg@kunikpok!uucp
Newsgroups: sci.electronics
From: wa2ise@cbnewsb.cb.att.com (robert.f.casey)
Subject: My dead Yahama model CDX2 cd player
Keywords: fix it?
Organization: AT&T
Date: Sat, 11 Apr 1992 20:38:07 GMT

I have a dead CD player, a Yahama model CD-X2.  Got it about 8 years
ago.  Has (or had) "Double resolution digital filter" which probably
means 2x oversampling.  It also has 2 problems:  1st problem is a
tendency to mistrack when playing CDs (sometimes really screws up,
then reload the CD and it may play fine).  Lived with that for a while,
then I bought a Magnavox with 4x oversampling.  Took the Yahama to my
parent's house to listen to CDs I might buy in the area.  2nd problem:
Few months later, the control function died.  Display would be all
scrambled, it wouldn't respond to the front panel buttons, it would
stick its tray out and not stop the tray motor, and such.  
Took the cover off, unplugged and replugged some connectors, no good.

Anyone have a similar failure on this model, and a possible fix?
I have the newer machine, so I'm not out of CD music.  Probably
not worth fixing?
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.electronics
Subject: Re: Ground faults? Buzzing sound from TV transformer:
Date: 8 Apr 92 07:23:44 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <1992Apr3.185137.24168@cunixf.cc.columbia.edu> reha@cunixf.cc.columbia.edu (Reha Elci) writes:
>There is an intermittent (lasting 10 seconds or so) buzz coming from my new TV
>which sounds like the ringing noise transformers sometimes have. Also, there
>are small pops and clicks that come from my speakers [connected to a power
>amp] even when the input is off [i.e. the equipment feeding its input is
>powered off]. Could this be a ground fault? My building was completed in '85
>so I am assuming all three prong sockets actually have ground and all the
>powers strips I have are 3-pronged. I doubt very much that the clicks & pops
>as well as the buzzing sound coming from the TV are normal. Any ideas?
>Thanks for the help.

One possibility is a bad thermistor in the automatic degaussing circuit
of your TV. That could cause intermittant buzzes and clicks as it opens
and closes. This could be a fire hazard.

Gary
From: togood@roger.lerc.nasa.gov (Chris Miller)
Newsgroups: sci.electronics
Subject: Re: Sony remote controll
Summary: cracked solder joint
Date: 15 Apr 92 15:33:17 GMT
Article-I.D.: eagle.1992Apr15.153317.10701
Organization: NASA Lewis Research Center [Cleveland, Ohio]

In article <7479@orbit.cts.com> dougm@pnet51.orb.mn.org (Doug Mcintyre) writes:
>>In sci.electronics, ldstern@rodan.acs.syr.edu (Larry Stern) writes:
>>...
>>>well except for the remote control. The remote had an intermittent problem
>> ...
>>>is, what usually goes? Is this worth fixing? And finally, can this LED be
>
>In my experience, it is generally a cracked solder joint  from the remote
>being ``dropped'' accidently or so. Since the circuit is so simple (yes an IR
>...

My Panasonic remote became intermittent after the kids experimented with
gravity.  Similar guts: one IC, etc.  The battery connection is with two
metal fingers soldered to posts (good joint); the posts were soldered to
the PC board.  The post to board connections were both cracked & looked like
a cold joint to begin with.  Resoldered them and it works great again.
--
From: fdeck@smiley.helios.nd.edu (francis deck)
Newsgroups: sci.electronics
Subject: PARALLEL PRINTER PORT
Date: 17 Apr 92 14:39:51 GMT
Article-I.D.: news.1992Apr17.143951.22684
Organization: University of Notre Dame, Notre Dame

I have two very nice documents which explain how to drive
the PC parallel printer port.  One deals with basic i/o, and
the other shows how to set up the printer port interrupt.
Since these are incredibly FAQs, I will send these documents
to any interested person who e-mails me at:

fdeck@grumpy.helios.nd.edu

f. deck
From: borkowsky@zodiac.rutgers.edu
Newsgroups: sci.electronics
Subject: Re: radar traps
Date: 9 Apr 92 23:20:30 GMT
Organization: Rutgers University Computing Services


	I've fought a few RADAR tickets in my short amount of time (I'm only
21. And, no, they weren't all mine.)

	I have a file of the what to do and what not to do in court, and the
ways to use in proving innocence. However, I can't send it to you because
the school's network is quite finicky and doesn't like corresponding with
UUCP. If you can either e-mail with another address you might have (or a
home address), I'll send it out next business day.

								Jason
						BORKOWSKY@ZODIAC.RUTGERS.EDU

  "If it ain't so, it might be; and if it were so, it would be. But as it
   isn't, it ain't. That's logic"
Newsgroups: sci.electronics
From: rubin@cis.ohio-state.edu (George Bush)
Subject: Easiest Way To Detect An Audio Signal ?
Originator: rubin@beech.cis.ohio-state.edu
Organization: The Ohio State University, Department of Computer and Information Science
Date: Wed, 15 Apr 1992 20:44:29 GMT

I have been doing some research looking up circuts in past issues of
Radio Electronics and various books to try to come up with a circut that
will detect a low level ( coming directly out of your preamp ) audio
signal.  There seems to be many twisted ways to do this, but I am looking
for the easiest and cheapest.  I want to incorporate a time delay from the
time the signal is detected to the time trigger is switched.

Unless there is an easier way I am going to use a 555 timer for the delay.
The main question I have is how do I convert the low level audio signal
into a DC current to trigger the 555 etc...

Thanks for any help                                             - Dan
-- 
  Daniel Joseph Rubin    |  "...A good football team for the alumni, parking
rubin@cis.ohio-state.edu |  for the faculty and sex for the students."
      GO        GO       |  - President E. Gordon Gee on the three things that
    BENGALS  BUCKEYES    |  a great university president must provide.....
From: ahahma@polaris.utu.fi (Arno Hahma)
Newsgroups: sci.electronics
Subject: Re: Plated thru holes
Date: 14 Apr 92 19:29:55 GMT
Organization: University of Turku, Finland

In article <1992Apr12.023534.6081@aplcen.apl.jhu.edu> kmd@aplcen.apl.jhu.edu (Kevin Doherty) writes:

>  I gather that there are several 'electroless' copper plating techniques
>out there; just drop an object in the bath, and it gets covered with

>  Is this a suitable technique for through plating?  If so, how do I do
>it?  If not, what should I do instead?

Yes it is, with some additions. First use the electroless bath on the
board. That will give you a very thin coating, too thin for any
practical use. Thus, the layer has to be thickened. That is done using
electroplating on the board after the electroless process. This way,
you don't even need any PCB-board at all. Just a plate of plastic, on
which you can deposit the copper yourself, as thick as you need up to
several millimeters (at which point you have no holes left anymore
;-). ABS plastic is particularly useful, since it can be easily etched
ensuring a firm adherence of the copper.

You can find electroless and electrolytic baths in any chemical
encyclopedia and references therein. Check the Kirk & Othmer's
"Encyclopaedia of Chemical Technology" or the Ullmann's "Enzyklopaedie
der Technischen Chemie". There are also books on electro- and
electroless plating. I have a good one ("Galvanotechnik"), the author
escapes my memory.

>  Thanks!

ArNO
    2
From: C31801MJ@WUVMD
Newsgroups: sci.electronics
Subject: Re: Have question about PCB layout program: padspcb.zip
Date: 17 Apr 92 20:35:54 GMT
Organization: Washington University, St. Louis
To:           NETNEWS@WUVMD

>
>In article <70463@ut-emx.uucp>, marty@ccwf.cc.utexas.edu (marty) says:
>
>it from the net, there are no sub-directories.
>
>Am I perhaps missing some important step when I unzip the program
>that will make it unzip into directories?
>
>If anyone has this program working, please let me know.

I think you should unzip the file to a floppy with the -d switch. Then the
installation program should work.
>
>thanks
>
>marty
>

Hope this helps. maciej paluszynski (c31801mj@wuvmd.wustl.edu)
Newsgroups: sci.electronics,rec.music.cd,rec.audio