HDTenEightyP/NetNews huggingface dataset:
From: whit@milton.u.washington.edu (John Whitmore)
Subject: Re: How do fluorescent lights work? 
Keywords: flurorescent
Organization: University of Washington, Seattle
Distribution: usa
Date: Fri, 9 Oct 1992 00:51:31 GMT

In article <1992Oct4.160255.29702@doug.cae.wisc.edu> siegel@hprisc-28.cae.wisc.edu (Jeffrey Siegel) writes:
>
>How do fluorescent lights work? I am specifically 
>interested in the steps that occur when you turn on
>a fluorescent light. I took one apart and found a
>two terminal device labeled "starter" along with a
>transformer and the tube itself. What is the "starter"

	A starter is a small time-delay relay, with a bimetallic
element in a neon tube.  On turning the fluorescent lamp ON,
the relay is initially CLOSED, and power flows through it to
heat the filaments on the ends of the tube.  After a short
period (during which the tube supposedly has reached breakdown
voltage and started) the bimetallic strip opens (due to heating)
and the neon starts to glow (which keeps the strip warm
enough to STAY open rather than cooling down and starting the
cycle over again).

	A manual pushbutton can replace the starter, and on some
old lamps, this was common.  I think the pushbutton was more
reliable.

	Starterless lamps use a saturable winding in the
ballast that detects current in the main circuit of the lamp,
and saturates a magnetic element which in turn shuts off the
filament current (and this, too, is more reliable than a
'starter'); cold fluorescent lamps use either higher initial
voltages or a speck of radioactive material to start the
discharge.

	John Whitmore


Newsgroups: sci.electronics
From: stettbac@isibee6 (Juerg Stettbacher)
Subject: Re: Stumped by op-amps
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: TIN [version 1.1 PL6]
Date: Wed, 7 Oct 1992 11:05:29 GMT


= I'm trying to boost a microphone (-50 dBm) to instrument 
= level (-17 dBm).  I looked through Horowitz & Hill's chapter 
= on op amps, and they have a circuit for a 40 dB amplifier.  
= It has 
= (...)
= I don't want to put 34+ parts together for a simple 
= amplifier!  Aren't there chips with all this in one package?  
= I doubt I'm the only one who's ever wanted a 40 dB 
= amplifier.  I was hoping there'd be a chip with 8 legs: 2 
= input, 2 output, 2 power source, 2 for a potentiometer.

Hi

My advice is: Don't waste your time unless you really know, what
you'r doing. The thing is that there are so many different mics,
and all of them need a different supply, impedance and amplification.


= I can't answer your question about building a mic preamp but I do have a
= few pieces of info that might be helpful.  The input level for consumer
= audio electronics is generally -10dB, not -17dB.  There are two main types
= of microphones: condenser and dynamic.  Dynamic mics require no power. 
= Condenser mics do need power.  This power (DC always) is provided by a
= battery or what is called phantom power.  Phantom power is a +48V DC
= (...)


This is true, but the power is not always brought in as phantom power.
Some mics have in fact four wires - two for supply, two for signal - or
three wires (common ground). The voltage ranges from 24 V up to 200 V 
according the mic type
Then there are condenser mics that don't need external supply, such as
electret mics (the name may be different). They have a permanent electric
charge on the condenser.

So, first check out, what type of mic you really have. Then design or
look for a appropriate schema. But consider the low voltage levels of
the mic output. Noise may cause a lot of trouble.


Good luck
juerg at acoustics lab, ethz switzerland
From: neal@cmptrc.lonestar.org (Neal Howard)
Newsgroups: sci.electronics
Subject: Re: Car antenna design help wanted
Date: 9 Oct 92 23:54:44 GMT
Distribution: na
Organization: CompuTrac Inc., Richardson TX

In article <1992Oct9.200441.4070@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>I presume you mean an FM antenna.  The usual FM car antenna is a 1/4-wave
>whip about 30 inches long, using the body of the car as a ground plane.
>This works quite well and is hard to improve upon.  If you wanted a better
>one, you'd have to make it longer, which might be awkward.  3/4 wave will
>work well, but you can't drive around with 90 inches of wire standing
>straight up.

 Sure you can drive around with a tall antenna!!! My dad's TV repair Chevy
 van had a 102" stainless steel whip mounted right in the middle of the roof
 back in the '60's ...best mobile CB radio antenna configuration you could have.
 It beat the hell out of all the tree branches he went under though. I used to
 have a co-phased pair of 96" fiberglass whips on the back bumper of my old
 '78 Ford LTD back in the CB craze days. They made for a darned good FM radio
 antenna as long as the car was pointed somewhat in the direction of the
 station since this setup was pretty directional. Out on the highway at speed,
 they would lay down almost parallel with the road :-)
From: stanb@hpnmdla.sr.hp.com (Stan Bischof)
Date: Sat, 10 Oct 1992 15:13:11 GMT
Subject: Re: RFI/EMI shielding of a plastic box
Organization: Hewlett-Packard, Santa Rosa, CA
Newsgroups: sci.electronics

In sci.electronics, ah335@cleveland.Freenet.Edu (Richard Banks) writes:



>a
>I have a plastic housing to put my circuit into but I'm worried about
>RFI interference.  I am going to try using aluminum foil, my question is
>how many layers do I need.  I know just one will not work. 

Why not? A complete lining of aluminum foil should actually work fairly well.
Don't leave gaps and make sure that the joints connect electrically.

>                                                              I remember
>from chemistry I when rutherford discovered electrons they passed
>right through one layer of aluminum foil, or was that gold foil?

Makes no difference- you are not in this case shooting electrons around anyhow
(or if you are you're doing something pretty wild in your little box!).
RFI typically results from EM radiation, not streams of electrons.

>At any rate could someone give me a good idea of how many layers to
>use to line the box with.   Thanks.  Richard Banks

A single layer should do just fine. Why not do simple experiment- measure
RFI with and without the shield? The effectiveness will be largely 
determined by the frequency of the interference.

Stan Bischof
Santa Rosa

********************************************************
These are just my own opinions and in no way should they
be confused with the opinions of my employer.
********************************************************
Newsgroups: sci.electronics
From: laird@stable.ecn.purdue.edu (Kyler Laird)
Subject: Radio Shack pagers
Organization: Purdue University Engineering Computer Network
Date:  7 Oct 92 19:26:12 GMT

RS here is selling the pager base and one mobile for $99.  I noticed
that this is a digital system and that the schematics are included.

Has anyone tried hacking this?  It operates near 27MHz with a reported
range of >2 mi.

I'd like to use the digital in and out for a alphanumeric pager.

Thanks!

--kyler
Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: Positive and negative side of diode
Organization: San Diego State University
Date: Fri, 9 Oct 1992 15:23:31 GMT

In article <1b2pfuINN2rn@usenet.INS.CWRU.Edu> ah335@cleveland.Freenet.Edu (Richard Banks) writes:
>From: ah335@cleveland.Freenet.Edu (Richard Banks)
>Subject: Positive and negative side of diode
>Date: 9 Oct 1992 02:06:54 GMT
>
>Please excuse my ignorance but I'm new at this.
>I'm putting together an electronic circuit and would like to know
>which side is positive and which is negative.  I guessed that the side
>which the ring on it is negative.  Is that right?  Please respond as
>quickly as possible and when I get a reply I'll cancel this article
>thanks.

Yes you are right. The "positive" side is anode, and the other cathode (the 
band side).

Peace and Prosperity!
  ---==< 110 >==---
Newsgroups: sci.electronics
From: vreeburg@fys.ruu.nl (Jurriaan Vreeburg)
Subject: Re: 25 ohm coax cable
Keywords: coax cable
Organization: Physics Department, University of Utrecht, The Netherlands
Date: Thu, 8 Oct 1992 12:02:25 GMT

In <bvr5pd.14o@wang.com> garyf@wang.com (Gary Field) writes:

>dhina@dxcern.cern.ch (Mourad Dhina) writes:

>>Hello,
>>i am trying to realize a circuit i found in an electronics magazine.
>>one of the components it uses is a semi-rigid coax cable of
>>25 ohms impedance. this is the first time i hear of this (i only
>>knew 50, 75 and 93 ohms cables, which are standard). anybody
>>knows where to find this?
>>Mourad

>Put two pieces of 50 Ohm cable in parallel. It should be exactly the same.
>Gary

After reading Gary's answer I had some doubt of its correctness. It implies
that by putting two 50 Ohm coax cables in series, one is able to create a 100 Ohm
coax cable, which is certainly not true.

I think that putting two cables in parallel doesn't change the impedance, since
the impedance is defined as:

                   L
Z = square_root ( --- )
                   C
L: inductance per unit length
C: capacitance per unit length

What happens if we put two cables in parallel: both the inductance and the capacitance
increase by a factor of two -> Z doesn't change!!! Putting two cables in series doesn't
change the impedance as well, since L & C are defined per unit length, which don't
change at all in that case.

Note that the above formula only holds for cables which are much longer than the wave-
lengths of the signals it caries.

-- 
Jurriaan Vreeburg                             email: vreeburg@fys.ruu.nl
Department of Physics and Astronomy           tel.:  (+31)-(0)30-534566
P.O. Box 80.000
3508 TA  Utrecht  Holland
From: jna@silver.lcs.mit.edu (no-one receiving)
Newsgroups: sci.electronics
Subject: Motor Control
Date: 10 Oct 92 06:42:50 GMT
Organization: We Take What We Want, Inc.

I'm trying to build a DC motor control circuit.
I'd like to get the motors running from 0% to 100%.
 
I'm considering running the motors with a pulses from a 555, using 
the 555's duty cycle to vary the speed.
 
Being able to change the directon of the motors via a simple switch 
is important...
 
I realize that there are chips available. Numbers anyone? TI manufactures 
one,  as does National Semiconductor.. How easy are they to get, and
how easy are they to control / wire / what external parts are 
required?
 
Leads, sources, and schems are appreciated. thanks!
  
--John
From: stock@acsu.buffalo.edu (Matthew D. Stock)
Newsgroups: sci.electronics
Subject: Serial line booster
Date: 12 Oct 92 00:22:03 GMT
Organization: State University of New York at Buffalo/Comp Sci

Hello.  Right now I've got a serial cable running between two PCs that is
approximately 50 feet long.  By using loopback tests, I've detramined that
all of the cables are working correctly, but one of the serial cards so too
weak to transmit the whole distance.
  What I was thinking of doing is adding a booster midway between the two
systems, but I am not sure the best way to do it.  Any ideas?
Thanks,
  -Matt

-- 
Matthew D. Stock         | think(X):- am(X).
stock@cs.buffalo.edu     | think(i).
			 | :? am(i).
CS @ Buffalo             | yes.
Newsgroups: sci.electronics
From: swanee@megadata.mega.oz.au (Geoff Swan)
Subject: Re: Dolby Surround
Organization: Megadata P/L, North Ryde, Sydney, Aust.
Date: Tue, 13 Oct 1992 07:14:25 GMT

In article <1992Oct12.012501.167@tplrd.tpl.oz.au>, derbyc@tplrd.tpl.oz.au (Derby Chang) writes:
> 
> Does anyone have an idea how they encode multiple tracks on two stereo
> tracks using Dolby Surround Sound encoding (Pro-Logic or otherwise)?
> 
> Derby Chang

Yes, the technical details of Dolby (TM) surround sound are available
in the Journal of the Audio Engineering Society, I'm not quite sure
of the issue, but sometime over the last two years. If anyone is interested
I can look up the issue and maybe even summarise the info on the net.

    Sla/n go fo/ill,
                    Risky B.
--------------------------------------------------------------------------
Geoff Swan (research & development)   _--_|\         swanee@megadata.oz.au
Megadata Pty Ltd                     /      \ 
2/37 Waterloo Rd, North Ryde,        \_.--._/               +61 2 805 0899
NSW 2113, Australia.                       v          (Fax) +61 2 887 4847

Newsgroups: sci.electronics
From: schaerer@isi.ethz.ch (Thomas Schaerer)
Subject: Re: Anti-feedback Circuit for PA Applications
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: TIN [version 1.1 PL6]
Distribution: usa
Date: Fri, 16 Oct 1992 19:23:17 GMT

david ercegovic (rqerce@lims02.lerc.nasa.gov) wrote:
: I am interested if anyone has a handy reference to the design of phase 
: cancelling or anti-feedback circuits for Public Address systems where one 
: is forced to place the speakers behind the microphone?
: 
: Any help/references to the circuit design appreciated.

One way to do this is frequencyshifting with a multiplcator.

Greatings from Thoma
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Re: Serial line booster
Date: 15 Oct 1992 15:52:46 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com

In article <1992Oct13.013641.11648@ccu.umanitoba.ca>, vnelson@ccu.umanitoba.ca (Gerald Vernon Nelson) writes:
> In <1992Oct12.035524.1202@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
> 
> >Interesting.  I have a similar problem where one of the machines is a
> >Sparcstation whose outputs are +-5 volts rather than the usual +-12.

That sounds like the internal jumpers are set to the RS423 position,
instead of RS232. I don't know which jumpers to change, but your field
service people should.

Steve
Newsgroups: sci.electronics
From: bonobo@Ingres.COM (David Victor)
Subject: Re: SPICE on SPARC
Keywords: spice sparc
Reply-To: bonobo@Ingres.COM (David Victor)
Organization: Ask Computer Systems Inc., Ingres Division, Alameda CA 94501
Distribution: sci.electronics
Date: 14 Oct 92 18:48:46 GMT

In article <JASA.92Oct14144301@dalton.inesc.pt> jasa@dalton.inesc.pt (Jose Antonio Soares Augusto) writes:
>Could someone in this group tell me where (if possible) I can get
>the SPICE program (version 2G which I believe is written in FORTRAN,
>should be compiled, or version 3 written in C)   to run on a SUN
>SPARCstation2? SPICE2G would be welcome, because, althoug older, is
>more or less bug-free.  

I too would be very interested in SPICE/SPARC...if someone knows 
where to get it, could they post the answer to the group too?

Thanks!

-David Victor
Newsgroups: sci.electronics
From: medin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Theremins
Reply-To: medin@catbyte.b30.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Date: Fri, 9 Oct 1992 18:46:35 GMT

In article <1992Oct8.202222.3117@oakhill.sps.mot.com>, hunter@oakhill.sps.mot.com (Hunter Scales) writes:
|> 
|> 	I just got back from Orlando, visiting Disney World.  At the
|> 	"Monster Sound Show" in the Disney-MGM Studios Theme park,
|> 	there was a theremin in the lobby!  They played the opening
|> 	sequence to "Forbidden Planet" on an old round TV tube, while
|> 	you play the theremin.  You can vary the volume with the left
|> 	hand and the pitch with the right.  I thought that you could
|> 	vary more than just the volume and pitch on a theremin.  Maybe
|> 	the "beat" frequency, too?  I would like to know more about
|> 	these things and, possibly, build one.  Does anyone have any
|> 	pointers to magazine articles/schematics?  Anyway, thanks in
|> 	advance for an info.

In a Theremin, the tone produced IS the beat frequency between two
RF oscillators operating at several MHz--one fixed in frequency
and the other variable, tuned through hand capacitance. Hand
capacitance also couples some of the RF
signal to the volume control plate where it is detected and used to
drive a voltage-controlled amplifier. I built one of these from SouthWest
Technical Products (long out of business, I think) back in 1977.
I've still got the plans, but sold the box to a band that just had
to have it.

I was just sort of fooling around with making one of these with
gate oscillators. In the process, I discovered that Popular
Electronics had produced the plans for a Theremin back in the 70's
too. The article is not in my archives.

-- 
 --------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    Intergraph Corp.				(205) 837-1174 (h)
       M/S GD3004
  Huntsville, AL 35894 		Internet: medin@catbyte.b30.ingr.com
				UUCP:  ...uunet!ingr!b30!catbyte!medin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)
Newsgroups: sci.electronics
From: cab@col.hp.com (Chris Best)
Subject: Re: Thunderstorms
Date: Wed, 7 Oct 1992 15:24:34 GMT
Organization: your service

>   We've seen lots of theory, but only a few experiences, of lightning
> doing damage to computer equipment.  Would anyone have some details
> about damage done to equipment?  This might give us a better idea of
> how much of a problem lightning actually is, direct hits, EMP, etc.

----------

A month or so ago, two storms came and went a few hours apart, both
very active, lightning-wise.  The second was more active than the
first, with nearby strikes every 10-20 seconds.  One strike was
so close that there was no delay between sight and sound - I swore
someone had lit a stick of dynamite in the front room.  Looking around
the next day, I found no craters or split trees, and the roof and
TV antenna were intact, but I know it was close.

Anyway, not much earlier than all this, I had decided to unplug all
the equipment in the stereo closet, the antenna and power to the
TV/VCR area, and power strips to my PC's (including the phone line
to an internal modem).  Good thing, as it turns out.  A little
while after the big strike, I tried to call a friend to see what
it was doing out his way, and used the cordless phone just to be
safe.  No such luck - it was out of commission, since I hadn't
thought of the phone lines to the PHONES.  In taking it apart later,
I found a transistor that had exploded, and black marks under the PCB
right where the phone connecter is soldered.  Also, the power cube
that plugs into the wall to power the phone was shot.  I don't 
know if the surge went out from the phone, or a surge in the power
lines did it, since it didn't damage another phone (also electronic) 
that was plugged into the same outlet and a phone jack just six 
wire-inches away.

I am convinced that a surge came in on the phone line, and expect
that one also came in on the power lines - not from a direct hit
on either, but just from the antenna effect all that wiring offers.

Lightning is really interesting stuff - I like photographing it
whenever possible, but a strike this close made me a little nervous!
Newsgroups: sci.med
From: dks@sr.com (Dave K. Sprow)
Subject: MEDICINE SLOWER TO CATCH UP
Reply-To: dks@srhqla.sr.com (Dave K. Sprow)
Organization: Silent Radio, Los Angeles
Date: Wed, 7 Oct 1992 19:46:09 GMT

To follow-up to my comment of a couple of days ago referring to the fact
that I was told about 20 years ago to not cook with aluminum cooking
utensils, not to drink from aluminum cans, avoid deordorants w/aluminum,et
c.  This was in reference to the discussed link between Altzenheimer's
and aluminum, my point being the medical professions bias and slowness to
accept "non-tradional" ideas and to debunk and belittle alternative
ideas/thoughts with little of their own research into some of this kind
of stuff.  I have alwasy thought a key reason is that our western
medicine seems to be fueled economically by the huge drug companies,
who make their money from treating symptoms, rather than looking for
underlying causes.  This creates a paradigm of thinking that apparently
is threatened by the idea of true preventative medicine.  Though this
attitude is getting better, there's a long way to go.

What brought this to my attention again is today's reports on CNN and
the newspapers that margarine is bad for you (yes, worse than butter)
and that is likely causes heart disease.  

I find this both humorous and sad as this was another thing that was
nutritionally suggested to me many years ago.

The article in the paper (L.A. Times) goes into depth about the original
Dutch study done on this reported in The NE Journal of Medicine in 1990.
"The Agriculture Department has now confirmed the Dutch study."  The
particular culprit is trans fatty acids.

Again, my only point is to ask the ridiculous, i.e, for the medical and
scientific communities to put more of their research dollars into
their own research from claims from more alternative approaches of
health care rather than just debunking everything from some superior
self-serving attitude.  Honestly, as far as I can see, these alternative
approaches seem to be about 20 years or so ahead of established
medical thinking. Medicine does a lot.  It would great if they could
be more open-minded and at least *consider* some of these things.  We
would all be better off if they people with the most money would put
some of those research dollars into this kind of research... with some
commitment to thr truth, not protecting special interest.

David


Newsgroups: sci.med
From: jelia@world.std.com (Joe J Elia)
Subject: Re: Selling the net to physicians
Organization: The World Public Access UNIX, Brookline, MA
Date: Fri, 16 Oct 1992 20:01:37 GMT

In article <7595@blue.cis.pitt.edu.UUCP> doyle+@pitt.edu (Howard R Doyle) writes:
>It was my understanding that the Online Journal of Clinical Trials was
>going to become available pretty soon. If my memory serves me right we
>are going to be able to access it through OCLC, Compuserve and the
>Internet. 
>If anyone has more information, especially how to actually subscribe to
>this thing, would you be so kind as to post it?

Here are the numbers for Current Clinical Trials:
(614) 764-6000
or (800) 848-5878

I'm a subscriber, and the thing I <don't> like is that there
isn't a way to contact the editors via e-mail. It's unseemly
to have to write them letters or call them on the phone.
Sigh.


-- 
Joe Elia <jelia@world.std.com>     | "This is this."  -- DeNiro  |
From: cam@castle.ed.ac.uk (Chris Malcolm)
Newsgroups: sci.med
Subject: Re: Treatment for snoring
Date: 12 Oct 92 17:05:28 GMT
Organization: Edinburgh University

In article <1992Oct9.194407.1669@cnsvax.uwec.edu> nyeda@cnsvax.uwec.edu (David A. Nye MD) writes:

>I've been trying to find a tongue retaining device to help my
>patients who snore, yet don't have obstructive sleep apnea that
>requires CPAP.

A popular operation for snoring in the (ex) USSR, where
dormitory-style sleeping is much more common, is to sew a tennis ball
between the shoulder blades of the pyjama jacket.
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205
Xref: sparky sci.med:18954 ca.general:1401
From: habersch@husc11.harvard.edu (Oren Haber-Schaim)
Newsgroups: sci.med,ca.general
Subject: Re: 'Super Lab'
Date: 10 Oct 92 21:39:14 GMT
Article-I.D.: husc3.1992Oct10.173915.16250
Distribution: usa
Organization: Harvard University Science Center

Converting military facilities to medical ones?   This wonderful
"solution" to what to do with military resources that will not
be funded, might not sit to well with those who are trying to
contain health care costs.   

I suppose the same poster has a solution to America's inexorable
rise in medical spending:  convert medical facilities to military ones!
Newsgroups: sci.med