HDTenEightyP/NetNews huggingface dataset:
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Transmission line question
Date: Wed, 16 Dec 1992 18:24:40 GMT
Organization: U of Toronto Zoology

In article <1992Dec15.202004.15878@ucsu.Colorado.EDU> barr@tramp.Colorado.EDU (BARR DOUG) writes:
>Some specs I have call for ethernet coax to be grounded in one location
>and one location only! I am wondering why this is. Antenna effects,
>current loops or something else. Does anyone know why this is the case?

Current loops.  Ground at one point isn't necessarily at exactly the same
voltage as ground at another.  Multiple grounds could result in quite
large currents flowing in the shield, producing both interference and
electrical hazards.

The original Ethernet spec called for no grounding at all, and that's still
the way most people wire their Ethernets.  There are weak safety arguments
for not leaving it floating, hence the change of spec.
-- 
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  henry@zoo.toronto.edu  utzoo!henry
Newsgroups: sci.electronics
From: grnwood@gagme.chi.il.us (Jerry Greenwood)
Subject: Re: How do you set up a security system?
Originator: grnwood@gagme
Organization: Gagme Public Access UNIX, Chicago, Illinois.
Date: Thu, 17 Dec 1992 15:18:59 GMT

 am trying to get some surplus parts that I recently bought to
> work as a home security system.  I am using a RADIONICS Omegalarm
> D1112 system with the wall controller (a keypad tha new
> one????  It keeps asking for the old code (to silence the alarm),
> and I don't have this....  Is it hard-coded on a chip when it is
> reset or does it default to some easy to use number...  Any
> ideas????

Yes, there is most likely a prom chip in there that has a 4 diget code.
You need that code or another prom chip who's number you do know.  Also,
earlier in you post you mentioned about putting a 1k resistor somewhere.
All alarm loops whether they have something hooked up to them or not should
be terminated in a 3k resistance.

-- 

Submitted for your approval.....
Jerry Greenwood                                                      N9NRG
grnwood@gagme.chi.il.us                                       312-545-2219
                                   1st of 6       
--
Xref: sparky sci.electronics:21193 sci.energy:6277 rec.autos:30196
From: pngai@adobe.com (Phil Ngai)
Newsgroups: sci.electronics,sci.energy,rec.autos
Subject: Re: Flywheel batteries as EV power source
Date: 19 Dec 92 19:28:19 GMT
Organization: Adobe Systems Incorporated

In article <1992Dec19.065254.8562@athena.mit.edu> ankleand@mtl.mit.edu (Andrew Karanicolas) writes:
>A major disadvantage that I see with the flywheel scheme is the amount
>of time it would take to "charge" it up from zero energy.  If the
>flyweel can provide a large amount of output power for a long time,
>then it should take at least the same time to charge it back.  A
>scheme where flywheel systems are interchanged at "fuel" stops could
>alleviate this issue.

If I were a terrorist, I would drool at the thought of being able to
get such wonderful bombs so easily... All you'd have to do is arrange
for the vacuum valve to be opened on command or the magnetic bearing
to be turned off, etc.

BOOM!

-- 
My opinions are my own.
From: bender@oobleck (Duke of Canterbury)
Newsgroups: sci.electronics
Subject: Re: how many pins on a 486 chip??
Date: 16 Dec 1992 02:55:17 GMT
Organization: SPARK's R US
Reply-To: bender@oobleck.eng.sun.com
NNTP-Posting-Host: oobleck
X-Newsreader: Tin 1.1 PL3

Curt.Miller@launchpad.unc.edu (Curt Miller) writes:
: 
: 	I was wondering how many pins there are on a 486 microprocessor
: chip?

why?

--
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 mike bender  DOD# 007  for sale: NX-650 $1950/obo      415-863-8913 (home)
 1991 FJ1200                       Honda DP bike
 bender@oobleck.eng.sun.com    nothin' witty here	415-336-6353 (work)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Organization: Queen's University at Kingston
Date: Fri, 18 Dec 1992 21:51:26 EST
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: Walkman Modification
Distribution: usa
 <92353.094726SOBCZAK@MAINE.MAINE.EDU>

>In article <BzDEtE.K5K@bcstec.ca.boeing.com>, mce5921@bcstec.ca.boeing.com
>(Martin Emde) says:
>>
>>Does anyone know how to modify a Walkman FM Receiver such that it operates
>>over the 108-136Mhz frequency range (aircraft voice communication) or
>>know if this is even possible?

Yeap.  It is possible.  I remember doing that in high school after
reading something in the book store.  I live closed to the airport
back then.  (So it was something simple enough.)

In article <92353.094726SOBCZAK@MAINE.MAINE.EDU>, Robert A. Sobczak
<SOBCZAK@MAINE.MAINE.EDU> says:
>
>Yea, I do.
>
>First, go buy an AM radio that receives in that range, because that what
>aircraft radios transmit on.  You can tune to the freq, but you have to

>Rob

That's one way of doing it.  Get an old FM radio (pre-chips days).  I am
not much into radio stuff, but I remember there is a trick in the
radio that uses a pair of diodes and one of the IF cans (the black one)
to change the FM signal back to an analog signal.  You basically detune
that IF coil to get ride of the FM demodulation. (Might want to find out
how it works by picking up a book at the libraray.) As for the frequency
part, you'll have to stretch the coils for both the local oscillator and
the tuning coil to shift their frequency ranges up.  You do a bit at a
time so that you can still pick up the upper stations on the lower part
of the dial.  It gets tough hacking those tiny little walkmans. :(

K. C. Lee
Elec. Eng. Grad. Student
Newsgroups: sci.electronics
From: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
Subject: Re: Rechargeable lithium batteries?
Date: Mon, 14 Dec 92 22:28:42 GMT
Reply-To: pmalenfa@kitkat.webo.dg.com (Paul Malenfant)
Organization: Data General Corporation, Westboro, MA

In article <1992Dec11.162112.3468@meiko.com>, simont@meiko.com (Simon Turner) writes:
|> 
|> Dowty make a rechargeable lithium ion battery.
|> 
|> ...
|> 
|> Simon.
|> 

I'd be interested in any of the following for Dowty:
phone number/address/city/state

-- 

Paul Malenfant
pmalenfa @ kitkat.webo.dg.com (508-870-6460)
Newsgroups: sci.electronics
From: reid@ucs.indiana.edu (Frank Reid)
Subject: Re: Telephone Headsets
Organization: Indiana University
Date: Sat, 19 Dec 1992 18:12:58 GMT

In article <1992Dec18.230348.18944@opus.hunt.inmet.com> lenny@hobbs.hunt.inmet.com (Lenny Goodman) writes:
>From: lenny@hobbs.hunt.inmet.com (Lenny Goodman)
>I've been looking into telephone headsets (the things that telephone
>operators usually wear) and the prices are much higher than I expected:
>$160 - $200 and UP.  Basically, the thing consists of half a headphone,
>a microphone, and a small amplifier.  I would have thought that the price
>would be $60 to $80.  Does anyone know why they are so expensive; or,
>does anyone know a source where the price is more reasonable??  Thanks.
>
>  -- Len

The ones I'm familiar with are made by Pacific Plantronics.  The cost
is as you said if you get them from the manufacturer or places that
sell stuff for airplanes.  You can get all models for $5-$30 at hamfests.
They look neat, people rip them off, then can't figure out how to use
them with ham equipment, so sell them cheap.  See _Ham Radio_ magazine
Oct. 1981, p.18 for an article about how to do it, including schematic
for discrete-component amplifier for Plantronics MS-50.  Copy for SASE.

BTW, don't share the kind with the ear plug and sound tube-- It's a 
good way to transmit ear infections.  If you get a used one, sterilize
it first.

--

Frank Reid   W9MKV     reid@ucs.indiana.edu
PO Box 5283
Bloomington IN 47407
Newsgroups: sci.electronics
From: gerry@bluemoon.use.com (Gerard M. Foley)
Subject: Re: CD-ROM drive, program and CD Music
Organization: Blue Moon BBS ((614) 868-998[024])
Date: Fri, 11 Dec 92 22:14:34 EST

     This reported a gap of a second or a fraction in the music
when the Sony 7205 CD-ROM player was used to play a CD disk.  The
interruption occurred at the switch from one track to another.
I played the same disk on a CD player (one meant for music), and
there was no perceptible interruption at this point on the disk.
Thus the problem must originate either in the program used to 
control the CD-ROM player, or in the player itself.
     I wonder if this defect occurs with other CD-ROM players and
the programs supplied to play music through them.

gerry@bluemoon.rn  My amateur radio callsign is K8EF, and my
packet radio address is K8EF@W8CQK.OH.USA.NA
Newsgroups: sci.electronics
From: kong@leland.Stanford.EDU (Kong Kritayakirana)
Subject: Opamp Based Integrator
Organization: DSG, Stanford University, CA 94305, USA
Date: Sat, 12 Dec 92 10:31:34 GMT


Hi Netters:

I am new in electronics land, so please be gentle....
I have a question. I want to a build an integrator (an opamp based) but I
heard horror things about opamps voffset and stuff. So any improvement on
the following circuit is much appreciated.


              +-------R2-----------+
              |                    |
              +-------C------------+
              |                    |
              |    |\  +-- +Vs     |
              |    | \ |           |
              |    |  \|           |
              |    |   \           |
 Vin ----R1---+----| -  \          |
                   |     \---------+ Vout
                   |     /
              +----| +  /
              |    |   /
             GND   |  /|               R2 >> R1
                   | / +-- -Vs
                   |/

1. I don't need an opamp with awesome slew rate to make an integrator, right?
2. How do I deal with Voffset problem.
3. This is going to be used in a high precision, low noise data acquisition.
   The professor I work for doesn't know anything about electronics, but he
   WANTS LOWEST POSSIBLE noise. What opamp should I use for Vinput with band
   width of about 500kHz. The circuit is NOT a power circuit.

Please email reply. Thanks in advance. Hope I can learn more about electronics
and contribute to the group in the future.

Kong	(kong@leland.stanford.edu)

PS: The text I have is 1. Art of Electronics by Horowitz and Hill
                       2. Some TI databook on opamps

Xref: sparky sci.electronics:20780 rec.audio:16741 alt.guitar:10874 rec.music.makers.guitar:941
From: mutrh@uxa.ecn.bgu.edu (Todd R. Haverstock)
Newsgroups: sci.electronics,rec.audio,alt.guitar,rec.music.makers.guitar
Subject: TEST Cassette??
Date: 15 Dec 92 20:50:08 GMT
Organization: Educational Computing Network

Is there such a thing as a TEST Cassette for use in a tape deck in adjust
the head height and tape speed (or pitch) to the EXACT standard?  If so
where can I get one?  Pleas email me.  THanks

Todd R. Haverstock
mutrh@ecnuxa.bitnet
mutrh@uxa.ecn.bgu.edu
From: Gess Shankar <gess@knex.Gwinnett.COM>
Newsgroups: sci.electronics
Subject: Source for tuning fork controlled oscillators
Date: Mon, 14 Dec 92 11:23:53 EST
Organization: |<><>| Knowledge Exchange, GA, USA |<><>|

Hi netters,

I am looking for a supply source for tuning fork controlled crystal
oscillators.. freq 215Hz +/- 5Hz. Excitation voltage to vibrate the
tuning fork is around 200v. Can anyone recommend a manufacturer/
distributor for this type of parts?

GeSS
--
Gess Shankar      |<><>|Internet: gess@knex.Gwinnett.COM                |<><>|
Knowledge Exchange|<><>|{rutgers,ogicse,gatech}!emory!gwinnett!knex!gess|<><>|

Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: andyh@chaos.cs.brandeis.edu (Andrew J. Huang)
Subject: Re: Flywheel batteries as EV power source
Organization: Brandeis University
Date: Wed, 16 Dec 1992 19:24:56 GMT

In article <1992Dec15.194558.2556@adobe.com> pngai@adobe.com (Phil Ngai) writes:
<regarding flywheel energy storage>
>But how hot would this "cotton" be? You're dumping what is presumably
>the equivalent of several gallons of gasoline's worth of energy.
>That's a very large amount of energy.
>
>I hope they do lots of crash tests before unleashing such a dangerous
>technology on the unsuspecting public.

<I have to admit an emotional response to this since I think that
flywheels have tremendous potential.>

1. I think that it is unfair to call it "such a dangerous technology"
based solely on your own opinions, without having done any
investigation on your own.

2. There are several places for the energy to go during an explosion.
Since the energy is kinetic, a lot of it will end up as particle
velocity.  Some will dissipate into the air as air friction (some hot
air as a side effect).  A quantity of energy will go into the
mechanical breaking of the flywheel disk itself.  Some more will go
into the penetration of the flywheel housing.  What residual energy
escapes these will have to be determined by testing.

3. You don't need to destroy cars to test the safety/danger of
exploding flywheels.  You just take a flywheel, spin it to 10 times
its rated capacity, and give it both barrels of a 10ga shotgun loaded
for elephant.  If it explodes, you measure the explosion.  If not,
send it to Ralph Nader for further tests.

The potential for these IS tremendous.  As I remember, the power
output of a flywheel is roughly "equivalent to a V8" in a much smaller
volume and weight.  Couple this with a super efficient small engine
running full time at maximum efficiency, minimum pollution to keep the
flywheel "charged" and you can get power, economy, cleanliness and range.

-andy





Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: olsen@vetmed.cvm.uiuc.edu (Aart_Olsen)
Subject: Re: Flywheel batteries as EV power source
Organization: UIUC -- Vet Med
Date: Thu, 17 Dec 1992 17:23:23 GMT

In article <BzEsw7.57B@cs.uiuc.edu> morrison@cs.uiuc.edu (Vance Morrison) writes:

>1) Slow down the rate of energy dumping. ...

This is what laboratory ultracentrifuges do.  Usually the rotor housing
is contained in a thick bronze casing which "slowly" absorbs the kinetic 
energy.  I once heard an ultracentrifuge blow, and it sounded like a freight
train for maybe five minutes.  Lab centrifuges contain a surprising
amount of energy--even though they have relatively small rotors and big 
motors they take quite a while to get up to speed because so much has to 
be pumped into them. 
-----------------------------------------------------------------------------
Aart M. Olsen   University of Illinois at Urbana-Champaign   a-olsen@uiuc.edu
-----------------------------------------------------------------------------
Newsgroups: sci.electronics
From: rhaack@carina.unm.edu (Rob Haack)
Subject: Here's How to Install the PADS Demo.
Date: Mon, 14 Dec 92 11:04:58 GMT
Organization: University of New Mexico, Albuquerque


	This seems like a FAQ, so I thought I'd share this info with the world.
Here's how I got the PADS demo to install:

I.   Get the files.  There are 3 of them: PADSLOG.ZIP, PADSPCB.ZIP and
     PADSLIB.ZIP.  They are available via anonymous FTP at
     wsmr-simtel20.army.mil in the directory pd1:<msdos.cad>.

II.  Unzip each zip file onto it's own 1.44M floppy, using the -d option (to
     preserve the zipped directories).  I think this looks something like:
     pkunzip -d <file>.zip a:  (or b: or wherever your 1.44M floppy is).

III. Run the program called 'PINSTALL.EXE' off either the PADSLOG or
     PADSPCB disk.  Do a software and hardware installation for both
     PADS PCB and PADS LOGIC.

IV.  Use the batch files to run the programs.  Directions are in the
     documentation that winds up in the directories that the install
     program creates.


Hope this helps someone.  Later...

                                       Rob

__________________________________________________________________________
Rob Haack                                            rhaack@carina.unm.edu
University of New Mexico
__________________________________________________________________________
Newsgroups: sci.electronics
From: rrhoades@cs.umr.edu (Ron Rhoades)
Subject: LCD vendors
Date: Fri, 11 Dec 1992 20:29:10 GMT
Distribution: usa
Organization: University of Missouri - Rolla
Originator: rrhoades@mcs213e.cs.umr.edu


I'm wanting to use a LCD about the size used in the TI-85 and HP 48sx calculators but i haven't been able to find a company that sells them.  I'd appreciate
any names of companies that sell them.

						ron rhoades
						rrhoades@cs.umr.edu
From: iqbal@omaha.eel.ufl.edu (M.Iqbal)
Newsgroups: sci.electronics
Subject: Re: Shareware/freeware PCB/schematic-capture programs FTP-able?
Date: 16 Dec 92 01:24:09 GMT
Organization: University of Florida

In article <gf_4sDW00iV4M8Vp9a@andrew.cmu.edu>, jmce+@andrew.cmu.edu (James Ryan Miller) writes:
|> 
|>     Yeah, I got the PADS stuff off wuarchive.wustl.edu.  It was in
|> mirror2/msdos/cad.  Unfortunatly, the installation program that comes
|> with it crashes on everyone's computer I've seen try it.  Basically, you
|> have to install everything manualy.  If you have any questions with
|> this, just send me mail.  
|> 
|>         Ryan Miller
|>         jmce@andrew.cmu.edu

I down loaded PAD a while ago. I did not get a chance to use it 
but I am sure it uncompresses fine. May be, I can put on our 
eel-ftp-anonymous site if enough request comes in.
-- 

---------------------------------------------------------------------------
"If your annual income today is $50,000, you have the same buying power as
the average coal miner did in 1949, adjusted for taxes and inflation," John
Sestina, nationally recognized Certified Financial Planner;  quoted in 1987.
                                            
      						 >><<<     >>><<<<
Iqbal@sioux.eel.ufl.edu		 		 (o o)     (o) (o)
University of Florida				 [ | ]        | 
                                  		   -         ---
From: albrecht@csd4.csd.uwm.edu (Chad Edward Albrecht)
Newsgroups: sci.electronics
Subject: Re: How to pulse the step motor 55SI-25DAWD
Date: 14 Dec 1992 19:12:10 GMT
Organization: University of Wisconsin - Milwaukee
Distribution: na
NNTP-Posting-Host: 129.89.7.4

I am just going to guess at this, but judging from the number and colors
of the wires, its a 4 step.  This means that your 2 red wires are the 
grounds and the other 4 various colors will be the Vcc on the 4 coils.
by pulsing these inputs like this:

			STEP 1		STEP 2		STEP3		STEP4
	INPUT #1_________|-|_________________________________________________
	INPUT #2_________________________|-|_________________________________
	INPUT #3_________________________________________|-|_________________
	INPUT #4_________________________________________________________|-|_

You can accomplish this using a simple D flip-flop.

Hope this helps!

Chad

--



-----------------------------------------   "The chess board is the world,
|	albrecht@csd4.csd.uwm.edu	|    the pieces are the phenomena 
|      albrecht@convex.csd.uwm.edu      |    of the universe, the rules of
|        acct146@carroll1.cc.edu        |    the game are what we call the
|       COMPUTING SERVICES DIVISION     |    laws of nature."
|	   UNIX  CONSULTING             |
|	   MICRO CONSULTING	        |           --T.H. Huxley
|     EMS 229-5370 Bolton 229-5317      |
-----------------------------------------
Nf-ID: #R:dadev.cebaf.gov:8113233:trsvax:288200047:000:42
Nf-From: trsvax.tandy.com!pauls    Dec 11 10:34:00 1992


Baretta 92F with 250 grain hollow points.

Xref: sparky sci.electronics:21107 sci.energy:6248 rec.autos.tech:16882
From: mwilson@ncratl.AtlantaGA.NCR.COM (Mark Wilson)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Date: 18 Dec 92 16:00:57 GMT
Organization: NCR Engineering and Manufacturing Atlanta -- Atlanta, GA

In <BzF5L0.LzK@cs.uiuc.edu> morrison@cs.uiuc.edu (Vance Morrison) writes:

|You are making two assumptions that may not be justified.  First you assume
|that all energy gets dumped as heat.   It is quite possible that this 
|energy can be dumped into some sort of chemical energy, (heat of fusion,
|vaporization or endothermic reaction).  Granted, I have not given a 
|possible scenerio, I merely point out that conservation of energy is NOT
|a proof of infeasibility.  

My whole point has been that the containment vessel will have to be big
enough to absorb all of that heat without melting or vaporizing.  I guess
getting very hot is not relevant as long as the vessel is suitably
insulated and kept away from the passanger compartment.

|Second, heat by itself is not THAT bad.  I really don't care if the flywheel
|compartment is hot enough to melt steel as long as I survive the crash 
|unburned.  If the crash was bad enough that I don't survive, does it matter
|that much if I get burned too?

This just means that we have to make the flywheel strong enough not to 
fail in any collision that is not likely to kill the passangers outright.

The problem with heat is that it can cause
|explosions if released too quickly.    Preventing explosions IS a goal
|that good engineering has a chance of accomplishing.  Again, I don't offer
|solutions, just pointing out that it is not as hopeless as you make it 
|out to be.

I never said that it would be hopeless, just that the amount of engineering
required to make this thing safe would make it too heavy and or expensive
to be usefull as a power source for a car.

|On the other hand, I could see how solving these problems might be expensive
|and that a better overall solution could be found to the EV problem by
|not using flywheels as the primary storage device.  

Agreed.
-- 
Mob rule doesn't become any prettier, just because the mob start to call itself
a government.
It ain't charity if you are using someone else's money.
Mark.Wilson@AtlantaGA.NCR.com
Newsgroups: sci.electronics
From: heyes@dadev.cebaf.gov (Graham Heyes)
Subject: DRAM refresh circuit needed...
Organization: Continuous Electron Beam Accelerator Facility
Distribution: sci.electronics
Date: Mon, 14 Dec 1992 19:32:16 GMT

Does anyone have an example of how to build a DRAM refresh
circuit using discrete TTL logic with perhaps the odd PAL
thrown in. I have been looking in handbooks from various
memory suppliers and their examples all use DRAM controller
chips. I am trying to keep costs down and want to use parts
I have on hand.

	If you ahve anything at all that you can paper mail
or FAX send me an E-mail.

	thanks
		Graham Heyes
Newsgroups: sci.electronics
From: CSMSMAS@MVS.OAC.UCLA.EDU (michael)
Subject: Re: Flywheel batteries as EV power source
Reply-To: csmsmas@mvs.oac.ucla.edu
Date: 19 Dec 92 23:41:42 PST

>A major disadvantage that I see with the flywheel scheme is the amount
>of time it would take to "charge" it up from zero energy.  If the
>flyweel can provide a large amount of output power for a long time,
>then it should take at least the same time to charge it back.  A
>scheme where flywheel systems are interchanged at "fuel" stops could
>alleviate this issue.

I would think that a flywheel could be charged a *lot* faster
than a battery.  The major limit would be the power source and
path into the flywheel -- not the wheel itself.

I once heard a large motor-generator started with a broken    .
starter -- no slow start.  In the few seconds (10?) it was
powered on it went from just turning over to what sounded like
full speed.  It sounded like a jet engine being wound up in the
building!  (This was without any load on the MG).

This ran on 3 phase 480 VAC power and I'd guess it was at least
50 KVA.  It output 400 hz power and could put out enough power to
run both an IBM 360/91 CPU and a 3033 CPU at the same time.
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Wed, 16 Dec 1992 20:18:40 GMT
Subject: Re: Ni-Cd storage state question.
Organization: Hewlett-Packard, Fort Collins, CO, USA