HDTenEightyP/NetNews huggingface dataset:
From: jeff@redgum.bcae.oz.au (j. pethybridge)
Newsgroups: sci.electronics
Subject: manchester -> clk , data (chip)
Date: 27 Aug 92 23:12:40 GMT
Organization: UCNV, Bendigo, Victoria, Australia
Originator: jeff@redgum.ucnv.edu.au


 Hello all,
     I am looking for a small ( 8->16 pin, <80mA ) chip that i can feed
with about 4800 baud manchester, and will give me clock and binary back.
    If a chip is not known about a circuit ( 3-4 chips ) would be nice.
                 Thanx for your time,  Jeff 
Newsgroups: sci.electronics
From: eb@lucid.com (Eric Benson)
Subject: Cordless phones
Reply-To: eb@lucid.com
Organization: Lucid, Inc., Menlo Park, CA
Date: 7 Sep 92 10:29:09

I'm looking for recommendations on cordless phones.  Basically,
everyone I know who owns a cordless phone hates it.  The sound quality
is terrible.  Is this just something one lives with?  I've noticed a
few recent models in the stores claiming to work in the 900 Mhz band.
Are these really better than the 49 Mhz models?  They are a lot more
expensive, like $300-400 instead of $70-150.  Spending that much isn't
out of the question, but I'm wary of new technology.  They claim to
have greater range, but I'm not so concerned with range, I'm more
concerned with the irritating, constant buzz on the line.  Also, I'd
like to have one that's comfortable to hold, and most cordless phones
are very bulky.  A few of them have the "flip-out" shirt-pocket
cellular style.  This is more convenient for transportation, but how
is it in actual use?  Has anyone tried connecting a hands-free headset
to a cordless phone?
Newsgroups: sci.electronics
From: weigand@pecan.cns.udel.edu (Steve Weigand)
Subject: Antennas
Reply-To: weigand@pecan.cns.udel.edu
Organization: University of Delaware, Newark
Date: Sun, 6 Sep 1992 16:03:50 GMT

Well... It's the beginning of yet another semester at college. Once again,
I am in a dorm without any good radio/tv reception. My question is:

How should I go about making a good antenna to pick up tv/radio? Assume that
I have all the wire I need. Also, what type of wire is best? 

Thanks, 
 - Steven Weigand
  (weigand@ee.udel.edu)

Newsgroups: sci.electronics
From: stettbac@isibee3 (Juerg Stettbacher)
Subject: Re: What is this 40pin chip?
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: Tin 1.1 PL5
Date: Mon, 14 Sep 1992 09:06:03 GMT

My name is... (klimasewski@fccvde.enet.dec.com) wrote:
: What type of 40pin chip is this?
: 
: D8749H 3006
: 207041-001B
: INTEL 80
: 
: The chip has a window so I assume it can be programed/erased.
: Can I copy this chip?
:                                                   thanks,
:                                                       Ken
: 


Hi ...

You have an INTEL chip in front of you (sorry).
The IC type is 8749, which is a EPROM version of the 8049.

Check the data book about copying.


Good luck
juerg at ethz switzerlan
Newsgroups: sci.electronics
From: ren@virga.ucar.edu (Ren Tescher)
Subject: Re: project design/build time (repost)
Keywords: Boing, Boing Boing
Organization: Research Applications Program/NCAR, Boulder, CO
Date: Fri, 11 Sep 1992 14:08:03 GMT

In article <1992Sep10.231958.16925@mailhost.ocs.mq.edu.au> johnh@macadam.mpce.mq.edu.au (John Haddy) writes:
]I suspect that the local news feed chewed up my last attempt to post this. If it
]didn't then please forgive the repeat post!
]
]If you've seen this before, I promise that this will be the last time! I truly
]expected that the the topic would arouse at least _some_ interest, however I've
]only had one reply (from nearby), leading me to suspect that the original post
]did't get very far.
]Flames to /dev/null please.
	Your post made it okay to Colorado, USA.  But my reply to the
address in your .sig. BOUNCED!
ren n0pvi
dona nobis pacem
Xref: sparky sci.electronics:15634 comp.sys.intel:1708
From: dcg5662@hertz.njit.edu (Dave Grabowski (KxiK))
Newsgroups: sci.electronics,comp.sys.intel
Subject: Re: Info needed on 16MByte SIMMs for PC
Date: 14 Sep 92 21:14:26 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.

In article <wright.34.0@lims01.lerc.nasa.gov> wright@lims01.lerc.nasa.gov (Ted Wright) writes:
>My Gateway 486/33E is advertised as accepting up to 64Meg of DRAM, but
>it has 8 SIMM sockets. Perhaps the Gateway saleperson is confused.
>
>Note that my computer came with 8 Megs in 4 SIMMs, these turned out to be
>512K by 36 bit SIMM modules, not the 2Meg by 9 modules that I expected.
>Ted Wright (wright@lims01.lerc.nasa.gov)

  My 486/33E initially came with 8megs, consisting of two 4MBx9 simms. I
have since upgraded to 16 megs. It should be noted that the 486/33E is
an EISA machine, and requires "EISA SIMMS." EISA Simms have about twice
the pin-density as regular simms. I learned this the HARD way, after
purchasing the WRONG chips from Microprocessors Unlimited. It was nice,
though, that they cheerfully accepted my return and dropped their price
(from about $195 to $160) when I told them how much Gateway was charging
for the same chips.

-Dave
-- 
-----------------------------------------------------------------------------
Kappa Xi Kappa - Over & Above!                         dcg5662@hertz.njit.edu
9 Sussex Ave., Newark, NJ (car theft capital USA)   70721.2222@compuserve.com
Newsgroups: sci.electronics
From: larryd@milton.u.washington.edu (Larry Desoto)
Subject: Re: A much better power inverter design
Organization: University of Washington
Date: Fri, 11 Sep 1992 16:37:55 GMT

wbrown@bevsun.bev.lbl.gov (Bill Brown) writes:

[...]

>Once again, we've gone 'round the full circle.

>Back in olden days, when dinosaurs roamed the earth, yea, even before
>the transistor came to be, all electronics were filled with strange
>devices called "Valves" or "Vacuum Tubes".  In order for these strange
>and wonderful devices to do useful work, or even provide Smoke, Smoke
>being the active ingredient of all things electrical, they had to be
>presented with High Voltage.

>In mobile or portable installations this High Voltage could be provided
>by various means; in some cases special batteries (known as "B" batteries
>for the High Voltage was also known as "B+") were used.  In other cases,
>generally where larger ammounts of "B+" were required, things called
>"Vibrators" or "Vibrapacks" were used.

Dynamoters...you forgot the true dinosaurs of High Voltage.  The proper
technique when using dynamotor powered ARC-5 transmitters was to press
the mike key and wait a second or so until the motor was up to speed.
It really brings back memories of adding another battery to the car's
electrical system to bring the voltage up to 24 volts for the dynamoters.


--
Larry                                   |   Thunder makes all the noise;
                                        |   lightning gets the job done.
larryd@milton.washington.edu
I have my opinion; the university has its own.
From: toddi@mav.com (Todd Inch)
Newsgroups: sci.electronics
Subject: Re: Floppy disk drive currents ?
Date: 14 Sep 92 20:09:22 GMT
Organization: Maverick International Inc.

In article <10666281.21.715565172@eng2.eng.monash.edu.au> 10666281@eng2.eng.monash.edu.au (KEVIN PRATER) writes:

>	Can anyone tell me what sort of maximum current you can expect to 
>get out of the supply line for floppy drives?

Answer: The maximum current (for each voltage) that the power supply
can put out minus the current being used by the motherboard and other
peripherals equals the total current available.

A 1/2 height Seagate drive I just looked at draws 0.8A from each the 5
and 12 volt leads.  A Panasonic floppy drive draws 0.27A at 12V and
0.47A at 5V.  I can't swear these are "typical", however.

So, if the power supply can handle another hard drive or couple more
floppies, or whatever, well, you can figure out the math . . .

I can tell you the 5V will have a lot more total current than the 12V.
Look at a power supply or two - the 150W or 200W rating or whatever is
the combined max power of all outputs, but most have maximum current
ratings printed on them, per voltage.
Newsgroups: sci.electronics
From: diegert@cs.sandia.gov (Carl Diegert [1424])
Subject: Tunnel Diodes
Organization: Sandia National Laboratories, Albuquerque, NM
Date: Wed, 9 Sep 92 16:00:32 GMT

Can someone suggest a source of tunnel diodes?
Thanks!

Newsgroups: sci.electronics
From: jshapiro@cs.umr.edu (Jeff Shapiro)
Subject: Global Positioning System (GPS)
Date: Tue, 15 Sep 1992 23:12:53 GMT
Organization: University of Missouri - Rolla
Originator: jshapiro@mcs213a.cs.umr.edu

I am interested in finding manufacturers of GPS receivers.

I am looking for spatial resolution on the order of 10 ft or better
with a computer interface.        
I would be intereseted in talking with anyone who has used a GPS Rec.  

Jeff Shapiro
jshapiro@cs.umr.edu

Newsgroups: sci.electronics
From: provost@vlsi.polymtl.ca (Benoit Provost)
Subject: Re: Phone circuit projects...
Organization: Ecole Polytechnique de Montreal
Date: Mon, 7 Sep 1992 04:52:55 GMT

	There is a book I used to have, but cannot find it now, called
"Telephone projects".  It was sold by Active Components in Montreal, and must be available at any Future Electronics suppliers.

	It's a hanbook full of funny projects about telephonics systems, and 
there is one just like the one you described.

	I know the telephone from Radio Shack would be cheaper, but if the 
challenge of a "do it yourself" project still interest you...

					Svann Le Terrible.


--
Benoit Provost                   |   Pattison's law of electronics:  t
provost@vlsi.polymtl.ca          |   if wires can be connected in two  a
Ecole Polytechnique de Montreal  |   different ways, the first way        yl
Montreal, Quebec, Canada         |   blows the fuse.
Newsgroups: sci.electronics
From: esrne@warwick.ac.uk (Mr P I Neaves)
Subject: Re: Line hum big problem in amplifier design
Organization: Computing Services, Warwick University, UK
Date: Wed, 9 Sep 1992 07:53:53 GMT

In article <BuA8JJ.328@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL GANDLER) writes:
>
> I built an amplifier that delivers around 120 watts into 4-ohms. I
>have noticed some bad hum in my speakers when there is no or little
>music. It sometimes gets worse when I raise the volume. If definetly
>sounds like 60hz and 120hz 180hz harmonics. I increased the capacitance
>in my dual polarity unregulated +-40V Dc power supply consisting of just
>a bridge diode and 2-4400uF Capacitors. Im not sure if the
>input stage is causing this. Im using 1458 op amps as buffer and voltage
>gain amps. I would appreciate any help Thanks in advance.
>
>  Neil Gandler

This sounds like a classic "earth loop" problem.

How have you *physically* wired the power supply and chassis earth ?

Phil
Newsgroups: sci.electronics
From: jmc@engr.uark.edu (John Carmack)
Subject: Help! My kaypro CP/M disks are dead!
Organization: University of Arkansas
Date: Tue, 8 Sep 1992 04:05:08 GMT

After several years of NON-USE, my Kaypro II CP/M 2.2 system originals are now
non-functional.  Plenty of sector not found errors.  I know it's the disks since
they do the same thing on another system.  
I need to find another copy of the Kaypro II Master and Master #1 disks for the
system , which include the pip, initdisk, MBASIC, ladders, Sbasic, and several
other programs which I can't remember off hand.  My originals have both had the
directories trashed.  My backup copies disappeared long ago.  Help!

Thanks
jmc@engr.uark.edu

Newsgroups: sci.electronics
From: shs@gribb.hsr.no (Stendal, Sverre H.     7-93)
Subject: Re: Need phone line sp
Organization: Rogaland University Centre
Date: Wed, 9 Sep 1992 14:28:38 GMT

In article <1992Sep3.191324.14987@cco.caltech.edu> sergeb@cco.caltech.edu (Serge J. Belongie) writes:
>From: sergeb@cco.caltech.edu (Serge J. Belongie)
>Subject: Need phone line sp
>Date: Thu, 3 Sep 1992 19:13:24 GMT

>Hello,
> 
>I need to know some of the specifications for phone line levels, namely:

>Vac, Vdc for:   Phone Onhook
>                Phone Offhook (dialtone)
>                Phone Offhook (button pressed)
>                Phone Onhook (ring incoming at ??hz)

>I have made some rather crude measurements myself with a multimeter,
>but they seem to change each time I measure them.  I tried checking
>the CCITT standards ftp sites, but they seem to have all disappeared.
>Any help with this information would be greatly appreciated.

>Serge

This is the spec in Norway! I guess it is international but I'm not quite 
sure. 
      Phone onhook/offhook 48 Vdc. (no ac)
      Phone onhook ring incoming  about 90 Vac (about 10-30Hz)

The impedance is set to 600 ohms, so that's why you get those strange
values when you measure. It depends on the internal impedance in each phone 
and on the line.

Sverre H. Stendal
Newsgroups: sci.electronics
From: jeremym@fraser.sfu.ca (Jeremy Thomas McDonald)
Subject: Is there a maximum write width for RAM?
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Sat, 5 Sep 1992 22:05:06 GMT


Wondering if there is a maximum pulse write width for static RAM (or
any other type of RAM for that matter).  I am looking at writing data
with a pulse of about 10us.

From: rkarlqu@hpscit.sc.hp.com (Rick Karlquist)
Date: Tue, 8 Sep 1992 16:07:31 GMT
Subject: Re: Circuit to multiply audio signals wanted.
Organization: Hewlett-Packard, Santa Clara, CA
Newsgroups: sci.electronics

In sci.electronics, gude@uniwa.uwa.edu.au (David J W Emrich) writes:

> Here is the outlay... I have two (later maybe more) audio signals, that
> are amplitude limited to 2V peak to peak, but no low-frequency
> limitations.  (Eg DC to 20kHz).  I want to "multiply" the two signals
> together, which, if I remember rightly, is the same as modulating one
> signal with the other.  Since modulation is symmetric, if 100%
> modulation is used, I figure that is the same as multiplying them
> together.  I know there is an op-amp circuit somewhere to do exactly
> what I want, but I can't remember, (it was 8 years since I started

Simply buy an analog multiplier IC from Analog Devices (such as AD534 
or AD633), Burr-Brown (MPY600) or Motorola (MC1495) (there are 
lots to choose from).  They are all based on the Barrie Gilbert 
multiplier circuit which is covered in most books on analog IC design.

Rick Karlquist
rkarlqu@scd.hp.com
Newsgroups: sci.electronics
From: mcp@netcom.com (Craig Presnell)
Subject: Need simple signal detection schematic
Date: Wed, 09 Sep 92 20:25:49 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

I'm not incredibly familar with electrical circuits, and how
to create them, but I do have a strong interest in learning and
playing around with some of this stuff. Something I would really
like to do is, for instance, is built a lighted breakout type
box for an RS-232 port on my PC. Something really simple, that
just activates a LED when a signal passes through. I would
also like to apply this to something similar, like using
the same kind of circuitry in a device that activates a LED
when a telephone is being used. Is there some generic 
transitor/LED circuit that I could use to apply to these
humble projects? While I surely don't know a lot about circuitry
now, I do hope to pursue it in the future. All and any help
that I receive will be GREATLY appreciated. Thanks.

-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
><         Craig Presnell          ><    mcp@netcom.netcom.com     >< 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Newsgroups: sci.electronics
From: iisakkil@vipunen.hut.fi (Mika Iisakkila)
Subject: Re: Success! Resist Pen Works in HP Plotter!
Organization: Helsinki University of Technology
Date: 12 Sep 92 13:42:04

agodwin@acorn.co.uk (Adrian Godwin) writes:

>How about using the standard pen to draw on a photosensitive resist, which is
>then developed and etched in the usual way ?

Or replacing the pen with a light source, like a high-intensity led
at the end of an optic fibre and using the pen down -signal to light
it? There are commercial equipment like this (I'm not talking of the
Gerber type photoplotters with aperture wheels).
--
Segmented Memory Helps Structure Software
Newsgroups: sci.electronics
From: patw@cserver.plexus.com (Pat Wilson)
Subject: Centronics Parallel Port
Organization: Plexus Corp. -- Neenah Wisconsin
Date: Tue, 15 Sep 1992 20:19:33 GMT

We will be designing a product with a Centronics Parallel
port on it.  I have a few questions regarding what exactly
a Centronics Parallel port is:

     1.  Is there a standard (such as EIA-232 for RS-232)?
         If so, what is it and how do I get it?
     2.  Or, is it a de facto industry standard?  If so, where
         do I find a definitive definition of pinout and
         signal timing?

Please E-mail responses and I will post a synopsis.  Thank you
in advance,
					Pat
From: frank@rover.uchicago.edu (Frank - Hardware Hacker - Borger)
Newsgroups: sci.electronics
Subject: Re: Cant find Transistor
Date: 4 Sep 92 19:44:00 GMT
Reply-To: frank@rover.uchicago.edu
Organization: Joint Center for Radiation Therapy
News-Software: VAX/VMS VNEWS 1.41

In article <Bu2ADv.12F@acsu.buffalo.edu>, v064mb9k@ubvmsb.cc.buffalo.edu (NEIL GANDLER) writes...
> 
>  Does anyone know where I can find a Transistor TO-3 case 2SD665.
>  Its used in power amplification. And I'm having trouble finding a mail
>order company that stock them. I would appreciate any help

	Look for someone that stocks sylvania ECG replacement semis.
	There ought to be a local parts store in buffalo

	2SD665 -> ECG 284	NPN-Si, AF power amp
				180 volts	16amp collector current
				150 watt power dissipation

	Or for RCA, try  SK 3836

   Frank R. Borger - Physicist    __       Internet:  Frank@rover.uchicago.edu
Michael Reese - Univ. of Chicago |___      Phone : 312-791-8075 fax : 567-7455
  Center for Radiation Therapy   | |_) _   The race may not be to the swift nor
    2929 South Ellis Avenue        | \|_)  victory to the strong, but that's
    Chicago, Illinois 60616           |_)  how you bet. - Damon Runyon
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Re: CSMA/CD on RS232?
Date: 15 Sep 1992 15:52:24 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com

In article <1992Sep15.150015.7409@sbctri.sbc.com>, tadams@sbctri.sbc.com (Tom. Adams 529-7860) writes:
> I was wasting time in a meeting, and came up with an idea that seems
> interesting to me.  Consequently I'm sure it's been done, or more likely
> been shown to be just incredibly stupid. :)
> 
> I'd like to connect multiple devices to an RS232 line, buswise.  All devices
> would either be programable, (i.e. PC's) or be frontended by a (cheap)
> microprocessor.  I'm wondering if CSMA/CD is a reasonable way to manage 
> very low speed bus contention.  If so, it would seem reasonable to transmit 
> address information, data, CRC's etc over the wire.  I'm not quite sure
> how to manage the Collision detect part, since I can't just look at 
> voltage levels on the wire.  Applications would be low volume data logging
> and control systems, ridiculously overpriced burglar alarms, etc.
> 
> Perhaps it would be more reasonable to just look at some twisted pair
> protocol that already has multi drop, like sdlc.
> 
> Opinions?


I think there was an article on that in Byte many years ago, one of the
Circuit Cellar series. It was a cheap multi-drop network using RS232
and a handful of diodes. You could try Byte backissues from the
early 80's, sorry I can't pin it down more precisely :-)

Collision detect was pretty simple, if I remember correctly the network
simply linked the Tx and Rx through diodes, and each device watched what it
sent coming back in through its receive line. If it didn't match, there
had been a collision & it backed-off & retried.


Steve

-- 
Steve McKinty
SUN Microsystems ICNC
38240 Meylan, France
email: smckinty@france.sun.com	   BIX: smckinty
Newsgroups: sci.electronics
From: whit@milton.u.washington.edu (John Whitmore)
Subject: Re: AC power inverter questions?
Organization: University of Washington, Seattle
Date: Tue, 15 Sep 1992 23:55:50 GMT

In article <1992Sep14.210900.1@acad2.alaska.edu> aslt@acad2.alaska.edu writes:

>Many inverters use square waveforms rather than sinusiodal waveforms. 
>Intuitively, though, it seems that significantly less energy will be 
>transferred from the primary to the secondary of the transformer using 
>square waves (input changes at discrete places in the waveform) than 
>would be transferred using sinusoidal waveforms (input continuously changing)
>What am I missing?

	First, a square wave is simply a lot of different frequencies
all lumped together; the efficiency of the transformer would have
to be less at high frequencies for the square wave drive to
have some disadvantage over the sine-wave drive.  Some sources of
energy loss ARE worse at high frequency (eddy current losses
in the transformer iron) while some are improved (saturation
losses).

	More to the point, the DRIVING  circuit is typically running
off a DC source, and can operate with nearly zero loss ONLY when
switching (which produces... square waves).  There are some tricks
to generating sinusoids, but they require extra inductors or many
taps on the transformer, and are not employed casually (nor cheaply).


>Along the same lines, presumably the outputs of inverters are square waves
>rather than sinusoids (I'm speculating, I don't know).  It seems you could 
>do some serious damage to the motors in some devices, drills, margarita 
>blenders, refrigerators, freezers, and such.  Any comments?

	Probably not; the series inductance in a motor results in
the higher frequency components of the square wave being...ignored.
If you fed an AC motor with DC, it'd damage it.  Feeding it with
too high a frequency, you'd simply lose torque (and the motor would
not draw current).  The worst case would be if it made the motor
respond acoustically (instead of a comforting hum, your refrigerator
would make an annoying BUZZZZZZ).

	John Whitmore



Newsgroups: sci.electronics
From: manson@ecf.toronto.edu (Bob Manson)
Subject: help with surge control and varistors
Organization: University of Toronto, Engineering Computing Facility
Date: Mon, 7 Sep 1992 17:58:25 GMT


Being forced to pay $120 to get a Cannon Bubblejet printer fixed after a 
(possible) voltage spike has caused one of my collegues to start thinking 
more seriously about surge protection.  He has a Dell notebook with 
an auto voltage/frequency sensing power supply.  When he travels, 
he uses the Dell power supply--through a regulator which I put together 
for him--to power the Bubblejet printer.  (The Cannon was not being powered
in this fashion when it got hit...it was plugged into it's own power
adapter.)  

The question is, if it *was* a voltage spike that hit the printer should we
be building some sort of varistor front end for the supplies(with different
varistors for different countries), or should the Dell power supply have all
of this stuff built in?  The Bubblejet "power supply" is just an AC adapter;
I've never seen an adapter yet that had much more than a couple of diodes
and a capacitor so I wouldn't be surprised at a spike being passed through
it.

Any suggestions--including hints about using and choosing varistors--would 
be much appreciated.


					thanks
					bob
					(manson@civ.utoronto.ca)
Organization: Queen's University at Kingston
Date: Sunday, 13 Sep 1992 22:51:12 EDT
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: A much better power inverter design

>In article <BuE4p8.5Bq@acsu.buffalo.edu> v064mb9k@ubvmsb.cc.buffalo.edu (NEIL
>GANDLER) writes:
>
>   I am a sophomore engineering student and have been researching and
>>trying to develop a new type of car amplifier that runs cooler and
>>the taim was at the power supply. 12v simply is not enough voltage
>>to power speakers to large amounts of power unless multiple amps
>>and speakers are used. So most manufactuers use mosfet power supplies

Radio Electronics March 92 has an article on such a design with a high
frequency switching power supply (I think rated for up to 300W) running
off MOSFETs.

K. C. Lee
Elec. Eng. Grad. Student
Newsgroups: sci.electronics