HDTenEightyP/NetNews huggingface dataset:
From: rhaar@albert.cs.gmr.com (Bob Haar)
Newsgroups: sci.electronics
Subject: Re: making mono from stereo
Date: 10 Nov 92 18:02:32 GMT
Reply-To: rhaar@albert.cs.gmr.com
Organization: G.M. Research and Environmental Staff

In article 10NOV199217405368@vxcrna.cern.ch, petry@vxcrna.cern.ch (PETRY,DIRK./PPE) writes:
|>How can the two speaker outputs of a stereo hifi set be combined to one?
|>
|>Since the human ear is only able to locate sources of sound if they
|>emit medium or high frequencies, it is not sensible to have two bass
|>speakers in a hifi set. A cheaper but as good solution would be to
|>have two medium and high frequency speakers, and only one bass speaker
|>connected to both output channels.
|>Surprisingly there no solution to this available, not even at  
|>specialized hifi electronics shops.

I have seen speaker systems that do this. Try looking at the Bose line.


---
	Robert Haar               InterNet : rhaar@gmr.com 
	Computer Science Dept., G.M. Research and Environmental Staff
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.
From: bk233@cleveland.Freenet.Edu (Jack W. Weinmann)
Newsgroups: sci.electronics
Subject: Re: WANTED: Sources for tube amp parts.
Date: 7 Nov 92 16:12:49 GMT
Reply-To: bk233@cleveland.Freenet.Edu (Jack W. Weinmann)
Organization: Case Western Reserve University, Cleveland, OH (USA)
NNTP-Posting-Host: slc10.ins.cwru.edu


In a previous article, markr@austlcm.sps.mot.com (mark rossman/xcn70) says:

>I am in the process of designing a tube pre-amp for a guitar amplifier and
>am looking for sources for parts.  I am looking for power transformers, tubes,
>sockets, etc.
>
>If you know of any mail-order shops that carry these items please email me.
>
>Thanks,
>markr@austlcm.sps.mot.com
>

There are a number of places that advertise mail order tubes.  One of my
latest Radio Electronics magazines has ads for the following:

Steinmetz, 7519 Maplewood Ave., Hammond, IN 46324   (send SASE)
           they claim to have the "oldest" and the "latest" - 
           also parts and schematics.

Kirby, 298 West Carmel Drive, Carmel, IN 46032  (send SASE)
           "Tubes, new, up to 90% off"

Antique Electronic Supply, 6221 S. Maple Ave., Tempe, AZ 85283 (send $2.00)
           "Over 3000 types in stock - also hard-to-find transformers,
            capacitors, and parts for tube equipment."

That's what I could find in my magazine.  

D I S C L A I M E R: I am in NO way affiliated with any of these companies.
                     I have NEVER ordered anything from them.
                     I therefore cannot vouch for their quality.

Note: If anyone has used them I would like to hear from them.  Also if
anyone knows of other companies that mail order tubes, please email the
information to me at bk233@cleveland.freenet.edu.

Jack Weinmann
Newsgroups: sci.electronics
From: vinlai@cbnewsb.cb.att.com (vincent.lai)
Subject: FAQ?:  How to filter out EMI/RFI from TV signal
Organization: AT&T
Date: Thu, 5 Nov 1992 18:51:01 GMT

I'm under the strong impression that this subject has been beaten to
death, but I went as far back as I could for previous articles and
couldn't find a thing.  Anyway, I our household does not have cable.
Instead, there is an antenna set up in the attic that is connected to
cable wires (don't know for sure) that run throughout the house.

Several appliances seem to introduce EMI/RFI to the TV signal, namely
my CD players (portable and component), my PC (386DX), and the usual
hair dryer, maicrowave, etc.  I'm interested in finding out what I can
do to make the TV signal more pure.  Here are some observations:

Moving the PC downstairs (away from the attic antenna) helps alleviate
interference.

Surge protectors featuring EMI/RFI filters didn't improve the quality
of the TV signal, regardless of where the protector was plugged in,
namely neither the TV or the PC.

UHF channels are more immune to EMI/RFI than VHF channels.

I'm really not looking forward to the idea of building Faraday cages
for ALL the appliances and the computer, so any suggestion that is even
remotely more elegant is appreciated.

--------------------------------------------------------------------
"Mom, we're hungry!" - Bud Bundy          "Why tell me?" - Peg Bundy

Vincent Lai
vlai@attmail.com
vinlai@cbnewsb.att.com
wcmnja!lai@somerset.att.com
--------------------------------------------------------------------
From: fdeck@dumpster.helios.nd.edu (francis deck)
Newsgroups: sci.electronics
Subject: Crystal-controlled FM XMTR?
Date: 6 Nov 92 20:40:19 GMT
Organization: OUC, University of Notre Dame

I've seen talk about one-chip FM transmitter circuits, but it
appears they are all slug-tuned and experience frequency drift.
Is there a simple circuit out there which is a monaural or
stereo (doesn't matter for my application) FM transmitter,
but which has a crystal timebase?  I'd imagine it'd use some
sort of PLL, but at 89 to 108 MHz, I'm lost.  Any help?

f.deck
physics
notre dame
From: curt@oasys.dt.navy.mil (Curt Welch)
Newsgroups: sci.electronics
Subject: Re: telephone humm any solution...
Date: 12 Nov 92 23:05:26 GMT
Reply-To: curt@oasys.dt.navy.mil (Curt Welch)
Organization: Carderock Division, NSWC, Bethesda, MD

In sci.electronics, heyes@dadev.cebaf.gov (Graham Heyes) writes:
>The strange thing is that some days there is no humm at all,
>other days you can't hear yourself speak.

You can't get hum inducted into a phone wire like this from
a nearby appliance or power cord.  The signal level is too
high.  You get it because one side of the blanced line has
been grounded somewhere.  I'd bet that the problem is in the buried
cable - not your house.  You can check this by taking your
phone out to the box and connecting it at that point.  Remove
the connection to you internal wiring first.  If it still
hums, it's not your problem.  The phone company will fix it
for free.

Does the hum increase when the ground outside is wet?  Does it
go away when it's dry?

Curt
From: kolstad@cae.wisc.edu (Joel Kolstad)
Newsgroups: sci.electronics
Subject: Re: Op amp configuration question
Date: 5 Nov 92 07:25:46 GMT
Article-I.D.: doug.1992Nov5.012546.17925
Organization: U of Wisconsin-Madison College of Engineering

Hi Mike,

In article <1992Nov05.043724.130701@zeus.calpoly.edu> mruddick@joule.elee.calpoly.edu (Michael Ruddick) writes:
>Be careful...you should only have to use one op-amp for what you are doing.
>It sounds like you want the op-amp to amplify your signal as much as
>it can, then pass it to another one that does the same thing.  Op-amps
>don't work like that...just use a standard non-inverting op-amp configuration
>and set your gain...if you set it too high, then the output will just switch
>back and forth between the two supply voltage rails --> high amounts of
>distortion!

I'm not sure what the original poster's question/problem was, so I'm not
going to comment too much on your response.

However, I did want to point out that there's a very good reason (in general)
for using two cascaded op amps (providing *x*y gain=*xy gain) rather than
using just one (providing *xy) -- the gain bandwidth product.  You can
show mathematically, in not too long of a time, that the closed loop
gain bandwidth product of two cascaded op amps is greater than that of
a single one for the same gain conditions.  This is one of the reasons
that trying to make, say, x1000 amplifiers out of one op amp is a very
difficult proposition.

Maybe someone will find this useful...

					---Joel Kolstad
					kolstad@cae.wisc.edu
Newsgroups: sci.electronics
From: ch@eiaut2.tuwien.ac.at (Christian Kral)
Subject: Re: Eproms
Organization: Technical University Vienna, AUSTRIA
Date: Fri, 6 Nov 1992 13:45:50 GMT

Hi Thorsten,

I guess your problem is pin 30 (A17 @ 27C020, NOT Connected @ 27C010).
Due to an higher address range of the 27C020 there is one more address line which has to be served. In the case of the less memory chip this line is free and obviously connected to the next pin (# 31 which has to be high during normal read operation) in order not to let the pin floating which can have damaging effects to the device (especially to CMOS types). Check this out in your application with power down and chip off the socket! If so, cut the line on the board if possible and connect pin 30 to GND(pi

n 16). This will select the lower address area in the two Megabit chip and will work with the other as well.

Good luck,

Christian Kral
(Inst. f. Automation, TU Vienna, AUSTRIA)
From: gfs@drutx.ATT.COM (Gary Skinner)
Newsgroups: sci.electronics
Subject: motorized potemtiometer FOUND
Date: 9 Nov 92 18:19:55 GMT
Distribution: sci
Organization: AT&T, Denver, CO

Mouser Electronics added a motor driven rotary pot
to their latest catalog  1-800-346-6873

10K 50K or 100K   3-6 volt motor  11 sec to fully rotate

$10 for 1,  $9 each quantity 10

------------
I don't work for these folks, just a satisfied customer
From: ikoutsel@sdcc3.ucsd.edu (Ioannis Koutselas)
Newsgroups: sci.electronics
Subject: Question on BeO , Be Cu
Date: 7 Nov 92 19:57:53 GMT
Organization: University of California, San Diego

Hello. I would like
to ask if someone kwows the minimum levels of exposure to BeO
and BeCu dust ?  I have accidentally (kind of) used BeCU
to make springs for an experiment, without ever knowing that
the dust of Be is also carcinogenic. Is it that there is
a minimum exposure level ?

Are the effects of Be chronic ? In other words do Be
atoms mutilate cells continuously in the human organism
or is there a decay in the action ? Can our body    
get rid of Be in some way ?


Thank you

Ioannis Koutselas
ikoutsel@sdcc3.ucsd.edu

Newsgroups: sci.electronics
From: strohm@mksol.dseg.ti.com (john r strohm)
Subject: Re: chaser lights
Keywords: chaser lights
Organization: Texas Instruments, Inc
Date: Thu, 5 Nov 1992 15:48:21 GMT

RE: construction of chaser light circuits

Everyone so far has proposed a digital approach to the problem.  Just to
be different, there is a fairly simple analog/mixed approach.

National Semiconductor makes three parts:  LM3914, LM3915, LM3916.  These
are LED bar-graph controllers.  LM3914 has a linear response.  (LM3915 has
a log response, and LM3916 is specifically set up for VU-meter applications.)

These parts basically require an analog voltage input, and you connect up
a handful of LEDs on the other side.  They can be set up for bar-graph or for
moving-dot (only one LED lit at a time).  Radio Shack used to sell them; I don't
know if they still do.

So the problem becomes one of constructing a suitable analog waveform and
gluing it to the chip.  (Note: if you need something other than LEDs for the
chaser lights, use optocouplers.)  There are lots of sources for waveform
generators out there: you can even get reasonable results from a 555 by
tapping the high side of the timing capacitor.
From: jmcc+@andrew.cmu.edu (Jason S. Mcmullan)
Newsgroups: sci.electronics
Subject: Pinouts needed: NTS/ECS 2056
Date: 4 Nov 92 11:35:49 GMT
Article-I.D.: andrew.key48pG00awMA2=lp3
Organization: Freshman, MCS general, Carnegie Mellon, Pittsburgh, PA

I need the pinouts for a NTS or ECG part - 2056   

Desc:  8 bit DAC.  16 pins.  

I need the pinouts badly for a sterio project (hooked up to my PC, of course)

Final design will be on a card and run both DACs off the 16 bit AT bus.

Thank you in advance...

Ezrec Nebarb

> Dorfal Sequence will initiate....  <
From: refling@sloth.eng.uci.edu (John P. Refling)
Subject: "Standard handbook for electrical engineers" for sale - $30
Newsgroups: sci.electronics
Organization: University of California, Irvine
Date: 6 Nov 92 02:30:33 GMT
Distribution: usa


Author:           Fink, Donald G.
Title:            Standard handbook for electrical engineers
Edition:          10th ed.
Date:             1968.
Publisher:        McGraw-Hill,
Description:      well over 1000 pages, hardback
Later edition:    12th edition in 1987.
Price:            $30.00

A $30 check to me gets you this item (including shipping in continental usa).

John Refling
Electrical Engineering Dept.
University of California
Irvine, CA  92717

          [ please reply to me directly, not to the newgroup ]
----------------------------------------------------------------------------
Newsgroups: sci.electronics
From: dbushong@wang.com (Dave Bushong)
Subject: Re: Autodialer
Organization: Wang Labs, Lowell MA, USA
Date: Fri, 13 Nov 1992 19:04:21 GMT

mgc@unislc.uucp (Marc Christensen) writes:

>Jim Karkanias (karkan@msdrl.com) wrote:
>: Does anyone know of a public domain or shareware program that would let me
>: assemble an arbitrary string of characters (representing those keys on a
>: telephone) and send them to a modem?  I'd like to be able to programatically
>: control a remote process; this process uses the phone as an interface...
>: 
>The problemI ran into and you probably will to was ...
>the modems all expect a dial-tone before they will dial. No tone No Dial.
>If the device "Answers" the phone then you will need to find a way around it.
>Do the regular/Leased line switches on a modem disable this feature?

>Making the modem dial is simple you need to send ATDT1234567890*# out the
>serial port for a standard hayes modem. some brands will also handle A,B,C,D
>codes like in a 12 digit pad.

Many modems support the X1..X4 command set, e.g., ATX0DT1234  will not
wait for a dialtone, and will not return as much of a result code
as something like ATX4DT1234.  You might want to try that.

Dave
-- 
Dave Bushong, Wang Laboratories, Inc.   Amateur Radio Callsign KZ1O
Project Leader, OCR products            kz1o@n0ary.#noca.ca.na
Internet: dbushong@wang.com
Newsgroups: sci.electronics
From: kgdykes@thinkage.on.ca (Ken Dykes)
Subject: Re: Television remote control units (the assasination thereof)
Organization: Thinkage Ltd.
Date: Wed, 11 Nov 1992 14:09:07 GMT

In article <1992Nov10.175119.14424@bnr.ca> mwandel@bnr.ca (Markus Wandel) writes:
>receiver, and in part by pumping TONS of current through the IR LEDs.
>1/2 AMPERE of current in each of two LEDs is quite reasonable.  The 
>LEDs and the battery survive because the duty cycle is small -- even
>if you hold a key down the LEDs are off most of the time.

dumb question

do parts "burn out" in remotes?

i have a cable-tv box (Zenith, marketed as a "wonderbox", a
converter/descrambler/remote all in one)

every couple years or so, the remote will spontaneously die.
not battery. not crud build up on sender/receiving units. dead. kaput.

since it's rented from the cable company, i simply take the remote part
in, and they give me another one.

however, in the last year i picked up an old vcr which uses a Zenith
remote that looks the same (a few more buttons for vcr controlling :-)

a week ago, BOTH died at the same time. i used both about 10 minutes
earlier, no problem. i go back to them and neither work.

well, the cable company replaced the converter remote, but i'm stuck
with a dead vcr Zenith remote.

i'll probably buy a low cost "universal" with Zenith preprogrammed into
it. but...

i'm curious, what is the weakness. what dies? is it fairly easy to fix
perhaps (replace leds?).
do spontaneous static discharges from sitting on the couch material or
carpet floor do them in or something?

even if i buy a universal, this is starting to bug me. am i somehow
assasinating the things? i hate mysteries.

-- 
   - Ken Dykes, Thinkage Ltd., Kitchener, Ontario, Canada    [43.47N 80.52W]
         kgdykes@thinkage.on.ca   postmaster@thinkage.com   thinkage!kgdykes
         harley-request@thinkage.on.ca             kgdykes@math.uwaterloo.ca
From: kingpin@mole.gnu.ai.mit.edu (Joe Smooth)
Newsgroups: sci.electronics
Subject: Amdek Eprom question
Date: 9 Nov 92 20:41:48 GMT
Article-I.D.: mole.KINGPIN.92Nov9154148
Distribution: sci
Organization: None

I have some Amdek EPROMs with 783217 printed on them.. (thats all that is
on them other than the Amdek symbol).. I've tried calling Amdek, and they
say they have no information on it, but I'm hoping that someone on the
net has these same EPROMs and could tell me what type they are (size, speed,
etc.).. Thanks a lot!
From: sad@camelot.bradley.edu (Shrijay Dalal)
Newsgroups: sci.electronics
Subject: VIC20 Tech manauls needed
Date: 13 Nov 92 21:47:40 GMT
Distribution: usa
Organization: Bradley University


Hello,

I'm looking for the tech manuals for a Commodore VIC 20.
SPecifically, I need the information for the cartridge port.  What is
the "pinout" and how do I access each one individually.

Thank you,
Shrijay Dalal

--
Shrijay Dalal                       | "Sometimes I think the surest sign that 
sad@camelot.bradley.edu             | intelligent life exists elsewhere in the
Student Computer Trainer            | universe is that none of it has tried
Bradley University                  | to contact us." -- Calvin of C&H
From: harrison@cs.ubc.ca (James Harrison)
Newsgroups: sci.electronics
Subject: Tracking the position of a diode in 3space
Date: 12 Nov 1992 16:13:11 -0800
Organization: Computer Science, University of B.C., Vancouver, B.C., Canada
Distribution: world
NNTP-Posting-Host: coyote.cs.ubc.ca


We have an application for the tracking of the position of a person in
a larger room with little or no hardware carried by the person being
tracked.  What we would ideally like to do is know the position of the
person in a large room (x, y).


Beam breaking etc are okay but would require too much hardware.
Cameras may be too computationally expensive...

So: Can the position of those antenna/diodes used in anti-theft
devices in clothing stores be used?  Emit a RF pulse and wait for it's
chirp? 

Anyone done this?  Know it can/can't be done?

Thanks
James
-- 
-------------------------------------------------------------------------------
James Harrison@cs.ubc.ca           `RPCing as fast as the network will let me.'
From: mikem@misg.csd.harris.com (M. K. McCole)
Newsgroups: sci.electronics
Subject: Re: 386 replacement chip
Date: 6 Nov 92 22:58:50 GMT
Organization: Harris Computer Systems Division, Ft. Lauderdale FL
NNTP-Posting-Host: misg.csd.harris.com

In article <1992Nov5.033718.20455@u.washington.edu> newsman@stein.u.washington.edu (Christian Ricci) writes:
-I just saw an ad for an Intel built 80386 replacement chip called the 
-RapidCAD Engineering CoProcessor.  It is supposed to give up to 70% improve-
-ment for technical applications.  It comes with two chips.  One replaces 
-the 80386 and one goes in the 80387 slot.  Any idea what this thing is and
-how it speeds up the computer?

 Chris

I've seen the Rapidcad, it's been out for a long time.  Basically it's a
386 with an integral math co-processor.  The chip that goes in the '387 
slot has a couple of gates on it to fool the bios into thinking it's a
co-processor.  The thing smells like a 486 with 386 pinout and no cache
to me.
Newsgroups: sci.electronics
From: tchannon@black.demon.co.uk (Tim Channon)
ReplyTo: tchannon@black.demon.co.uk
Subject: Re: Information wanted on EEPROMS
Distribution: world
X-Mailer: cppnews $Revision: 1.19 $
Organization: null
Date: Mon, 9 Nov 1992 21:28:24 +0000

> I need a EEPROM for an application, but I can't not seem to
> find one. Problem is that I don't know a manufacturer or
> part number for one. Could someone send me information on
> manufacturers of EEPROMS and maybe suggest some databooks
> where I could get more information?

I'm sorry but I find that amusing, your apparent company name follows...
 
> Organization: Intel Corporation

For starters try Xicor or Seeq, unless Flash would do. :-)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                
Xref: sparky sci.electronics:18364 misc.forsale.computers.pc-clone:606 misc.forsale.computers.d:275
From: tdb@cam-orl.co.uk (Thomas D Blackie)
Newsgroups: sci.electronics,misc.forsale.computers.pc-clone,misc.forsale.computers.d
Subject: Re: 486 CPU KOOLERS FOR SALE
Date: 5 Nov 92 14:59:45 GMT
Organization: Olivetti Research Ltd

In article <1992Nov5.083110.7351@u.washington.edu> bketcham@stein.u.washington.edu (Benjamin Ketcham) writes:

>Well, I can't say I've done any tests on lifetime vs heat...
 
Although important I don't think CPU lifetime is the main issue here, I
think it's short term reliability.


>Everyone seems to agree that lower temperatures are in general better
>for semiconductors.  However, the question seems to be, does the decrease
>in CPU temp that these fans achieve really make any real difference?  I
>find it hard to believe that it does.  I have actually *never* seen a
>CPU fail in my relatively small personal sample of systems...


Well I quess your sample really has been small, or you've been very
lucky.  In the past 10 or 12 years I have seen numerous examples of
systems failing due to overheating; of course it's difficult to say if
it's actually the CPU, but keeping the silicon cool certainly cured
many of the situations.  

More recently and specificaly here at Olivetti we have several DX2 and
50Mhz 486's which run perfectly when cooled but stiff when not.  When
left running on the bench in free air the CPUs run at pretty close to
85C, ie. the maximum specified.  When running at 20ns cycle times it
doesn't take much extra heat to add a couple nanoseconds to some of
the internal critical paths, thus resulting in stopped CPU!


>
>
Lots of deleted message....
>
>
>Plus, nobody has considered the possibility that these fans might do
>more harm than good.  For one thing, as any service technician would
>agree, I'm sure, the biggest problem impacting system reliability is
>often the users opening the box up.  The chances of slipping with a
>screwdriver and doing major damage are probably orders of magnitude
>higher than the chances of a CPU failing within even 10 years.  What
>about the vibrations and electrical transients introduced by these
>fans?  Were any studies done about these factors?  After all, they are
>bonded right on top of the CPUs.  I would imagine that the CPU sockets
>are probably a good bit more susceptible to failure or intermittent
>noise problems, exacerbated by vibration, than the CPU itself.

I agree. 

However from our experiences most cases just don't have
sufficient airflow over the CPU to keep these new breeds of processors
within spec.  To solve this we have been fitting small 12V DC fans
blowing air dierctly over the CPU, this results in about a 20C
reduction in CPU case temperature.  It doesn't add any height, there's
no mechanical stress etc.  There are lots of fans available about 60
or 80 mm square, try Radio Shack, they are probably also cheaper than
any of the various 'koolers' on sale.

So Ben, in short we have first hand experience of CPUs stiffing due to
overheating, and directed cooling solves the problem.

How about someone from Intel giving us the long term reliability
Newsgroups: sci.electronics
From: lnosek@ux4.cso.uiuc.edu (Luke Nosek)
Subject: Re: Are TV's interlaced? Why no flicker?
Organization: University of Illinois at Urbana
Distribution: na
Date: Sat, 14 Nov 1992 05:16:18 GMT

jdc3538@ultb.isc.rit.edu (J.D. Cronin) writes:


>Why don't ordinary TV sets flicker?  A friend told me that standard
>NTSC video signals are interlaced.  That doesn't make sense, since
>the picture should flicker enough to be unwatchable.  

>Any ideas on what's going on here?

>Jim

	Ah, but they are interlaced - and there is flicker!

	The difference lies in the kind of images that computers and tv's
get to display.

	A computer often displays thin crisp lines, boxes, etc. These things
have small features that may span a single scan line - consequently as
the lines alternate - these features flash on and off.

	A tv has pictures. The color transitions are smooth, and any lines,
text, boxes, are large because they need to be seen. Plus an ntsc signal
makes things a bit fuzzy, so if there are any tiny features you won't see them.

	Try this:

	Look at a good gif on an interlaced computer monitor - stand about as
far away as you would it were a TV.

	You shouldn't notice the flicker.
Newsgroups: sci.electronics