HDTenEightyP/NetNews huggingface dataset:
From: pashdown@javelin.sim.es.com (Pete Ashdown)
Subject: Amperage meaning?
Organization: Evans & Sutherland Computer Corporation
Date: Tue, 25 Aug 1992 19:23:12 GMT


Alright, so I admit it, I've forgotten a bit of my physics.  The question is
this:  I recently purchased a small transmitter that can work off either a 9
volt battery or a 12 volt power supply.  I happen to have a 12 volt power
supply that I use to power my laser, but it is at 2.5 amps.  I realize that
this amperage is far more than I need for the transmitter, but is it too much?

Does it give me more power for the transmitter?

Does it consume more power from the wall?  If I run this 12 hours a day, would
I be better off buying a lower amperage supply?

Will the amperage cause anything to overheat that wouldn't otherwise?

Thanks in advance for any advice.
-- 
MAIL ME about EXPENSIVE CDs!AMGIA 4EVR!SF2RULEZ(my license plate)!AlexP=MY.HERO

DISCLAIMER: My writings have NOTHING to do with my employer.  Keep it that way.
Pete Ashdown    pashdown@slack.sim.es.com    ...uunet!slack.sim.es.com!pashdown
Newsgroups: sci.electronics
From: wpns@miki.pictel.com (Willie Smith)
Subject: Re: GPS Availability
Organization: PictureTel Corporation
Date: Thu, 27 Aug 1992 17:04:24 GMT

In article <7480111@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> I've never really understood this. What possible difference does
>> several hundred meters error make to either:

>greatest example.  Best one I could think of right now.)  The military isn't

In some random SF book I read a few years back, some terrorists filled
a Learjet with explosives, hooked the autopilot to a GPS, and flew it
into the (???) embassy in Ottowa.  Yeah, I know, today they would use
the differential signal from a nearby airport...

Willie Smith
wpns@pictel.com

Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: Old laser rejuvenation
Organization: San Diego State University
Distribution: usa
Date: Wed, 26 Aug 1992 18:26:03 GMT

In article <1992Aug26.043710.27944@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (gordon hlavenka) writes:


>I have an _ancient_ laser which almost works.  It's a HeNe laser,
>model 3100 from Gaertner Scientific (circa 1969).  It worked for a
>while, but now has developed an electrical problem.

>This laser, when you get down to it, is basically an expensive beer
>sign with a couple of mirrors hung on it.  The tube does not run
>continuously any longer.  It flickered for a while, and now it just
>fires in bursts.

>The power supply consists of 2 transformers, 4 diodes, 6 resistors,
>and 2 big capacitors.  My first guess is that the caps have become
>leaky.  Any tips?

>It _does_ lase, when the tube fires.  So the optics are OK.

>(Yes, I know that for $50 I can buy a semiconductor laser with more
>power and a better beam shape.  That's not the point.)

>-- 
>----------------------------------------------------
>Gordon S. Hlavenka           cgordon@vpnet.chi.il.us
>  Don't forget:  Dave Barry/Joe Walsh in November!

You have lost the gas. You woudln't expect helium gas stays in the 
tube forever?


Peace and Prosperity!
  ---==< 110 >==---
Newsgroups: sci.electronics
From: bonobo@Ingres.COM (David Victor)
Subject: Re: Looking for Rack mount cabinets
Keywords: racks!
Reply-To: bonobo@Ingres.COM (David Victor)
Organization: Ask Computer Systems Inc., Ingres Division, Alameda CA 94501
Distribution: dfw
Date: 25 Aug 92 16:50:33 GMT

In article <1992Aug24.143629.11835@iex.uucp> mikek@iex.UUCP (Mike Keilhofer) writes:
>Does anyone know where I can buy 19" Rack mount cabinets for
>electronic projects? Or, possibly a sheet metal house that
>can/does/would built them?
>

Try EasyTech (2917 Bayview Drive, Fremont, CA 94538  1-800-582-4044).  They have a
nice selection of single, double and quadruple-space rack mount enclosures.  They
look essentially all black in the catalog, but they say they're finished in "gun-
metal gray".  The single space racks are $36.95 each, slightly less in quantity.

These guys are really nice to order from, and there's no minimum order.

-David Victor
(P.S.  No connection other than a satisfied customer!)
Newsgroups: sci.electronics
From: jmorriso@ee.ubc.ca (John Paul Morrison)
Subject: Re: M68HC11 info needed
Organization: University of BC, Electrical Engineering
Date: Sat, 29 Aug 1992 04:51:35 GMT

In article <keb2oo600UhWE8=LEa@andrew.cmu.edu> hk0w+@andrew.cmu.edu (Hanjoon Alex Kim) writes:
>Hi, thanks for reading this.
>I have no idea what kind of responses I'll get, since this is my first posting.
>I am currently working on a project which involves the Motorola 68HC11.
>Now, I ran into a problem with the Mac. The Mac C compiler for the 68HC11 that
>I have does not like to divide numbers or deal with floating points. And, 
>being a student, I don't have the money to buy a compiler that does. Do you
>know of any solutions to my problem? Maybe a cheap (~$20) compiler out there
>for the Mac? Or a way around my problem?
>Thanks in advance for any help you may be able to give me.
>
>Alex

The MC68HC11xx series has no math instructions, so the compiler wont do them.
Someone already sugested calling the Motorola Freeware BBS.

If you have the money for yet another more expensive 6811, you can check
out the MC68HC711 series (I think it's 711) which has built in math instuctions.



-- 
__________________________________________________________________________
 John Paul Morrison                     |
 University of British Columbia, Canada |
 Electrical Engineering                 |   .sig closed for repairs 
                                        |             
 jmorriso@ee.ubc.ca                     |
________________________________________|_________________________________
Hi! I'm a .signature dung-beetle. Add me to the rest of the crap in your .sig
Newsgroups: sci.electronics
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Re: Old laser rejuvenation
Organization: University of Central Florida
Date: Wed, 26 Aug 1992 19:49:17 GMT

In article <massoud.57@chemteca.sdsu.edu> massoud@chemteca.sdsu.edu (Massoud  
Ajami) writes:
> In article <1992Aug26.043710.27944@vpnet.chi.il.us> cgordon@vpnet.chi.il.us  
(gordon hlavenka) writes:
> 
> 
> >I have an _ancient_ laser which almost works.  It's a HeNe laser,
> >model 3100 from Gaertner Scientific (circa 1969).  It worked for a
> >while, but now has developed an electrical problem.
> 
> 
> You have lost the gas. You woudln't expect helium gas stays in the 
> tube forever?
> 
About five or six years ago I saw a little article in Applied Optics
about rejuvenating olf HeNe tubes by putting the tube in a chamber
with pressurized(?) He for a day or so.  The He would migrate back
into the tube and after a while the tube worked just like new.
Probably wouldn't want to overshoot though.  Can pressurize it in
fairly quickly, but would have to wait years for too much to
diffuse out again !-)
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu
From: jfw@ksr.com (John F. Woods)
Newsgroups: sci.electronics
Subject: Re: That Magic TV screen
Date: 27 Aug 92 11:33:39 EDT

aj008@cleveland.Freenet.Edu (Aaron M. Barnes) writes:
>Have any of you seen the 30 minute infomercial for the "Magic TV"?
>The point of the show is to get you to buy a plastic screen which
>you place in front of your 13" TV and the 25" screen magnifies th
>e TV to look like like a 25".

Rent a copy of the movie Brazil, and pay close attention to the computer
terminals (one of which I *want*).

>It appears to be a sound concept,but I wonder about the brightness...

So do I, so do I.

;-)

Newsgroups: sci.electronics
From: steve@nuchat.sccsi.com (Steve Nuchia)
Subject: PAL Foundry idea
Organization: South Coast Computing Services, Inc.  Houston
Date: Thu, 27 Aug 1992 22:28:19 GMT

Some days ago I posted a request for comments regarding
setting up a programmable logic service bureau.  The
response was sufficient to indicate that such a service
would be viable.  It has been added to my project list,
where is will not be lonely.

Thanks to all who responded.
-- 
Steve Nuchia      South Coast Computing Services, Inc.      (713) 661-3301
Newsgroups: sci.electronics
From: jon_sree@world.std.com (Jon Sreekanth)
Subject: Re: Phone in use light - help!?
Organization: The World
	<1992Aug21.212309.22093@serval.net.wsu.edu>
	<1992Aug22.194629.9065@athena.cs.uga.edu>
Date: Mon, 24 Aug 1992 02:59:11 GMT

In article <1992Aug22.194629.9065@athena.cs.uga.edu> mcovingt@athena.cs.uga.edu (Michael A. Covington) writes:

   Build mine instead (forthcoming in Popular Electronics) -- its impedance
   across the line is 66 megohms, well above the 0.7 megohm minimum.
                                                 ^^^^
As far as I remember, FCC 68 limits on hook DC resistance to 5M minimum,
below 100V. Maybe the GTE test procedure was to send out a repair person
when they found less than .7M, that's all. 

/ Jon Sreekanth

Assabet Valley Microsystems, Inc.           |  Fax and PC products
5 Walden St #3, Cambridge, MA 02140         |  (617) 876-8019
jon_sree@world.std.com                      |

Newsgroups: sci.electronics
From: dernis@binah.cc.brandeis.edu
Subject: Building PC Boards
Reply-To: dernis@binah.cc.brandeis.edu
Organization: Brandeis University
Date: Thu, 3 Sep 1992 20:26:02 GMT

Hello,
  I was waiting for a FAQ to be posted, but didn't see one, so I am
going to ask this though it is most certainly a FAQ.

Is there Software Available in the Public Domain for drawing scehmatics
and producing optimized layouts for PC boards.  When I say optimized
I mean minimum jumpers to avoid overlaps, weighting certain connections
in importance of shortness of line, etc.

I realize this is a tall order for Public Domain, if not is there something
cheap.  If this is not available what is the next best thing? 

Second how could I get my hands on it.

Third,  with this software, what is the most efficient way to etch it.  I
would specifiy that this would be for one or two working boards of a 
given type probably only one in most cases.  In some cases up to four or
five but that is it.


I have read the resist pen on a plotter, and milling bit on a plotter.
What about laser printer on acetate, I heard there are resist fluids
that can be hardened with UV light(black light), rinse, than etch?  Is this
the way it is normally done?

Why am I interested?  I am a PChem Grad Student and often end up building
small digital circuits for pulse delays and such.  Right now I use circuit
stick, or something like that, and 22 gauge wire.  Very sloppy!  Sometimes
some higher speed projects have a lot of cross talk.  I realize that printing
the circuit won't eliminate that immediately but I think it would go a
long way towards simplifing the debugging process, and may on its own eliminate
some of the problems.  Also keeping track of completed schematics is a problem
of mine, having them in a computer would help.

Thanks in advance,

Mitch Dernis
 
Newsgroups: sci.electronics
From: kludge@grissom.larc.nasa.gov ( Scott Dorsey)
Subject: Re: Need Antenna Help
Organization: NASA Langley Research Center and Reptile Farm
Date: Mon, 31 Aug 1992 22:20:08 GMT

In article <9208311937.AA01375@mml.ncsl.nist.gov> wilson@MML.NCSL.NIST.GOV (Ron Wilson) writes:
>Hi Netters,
>
>I need some advice.  Lately it seems that I have had a lot of interference 
>in the TV reception.  Most UHF stations get fuzzy and drift off and now 
>it's even happening to some network channels.  It's like the TV is trying 
>to pickup two channels at the same time.  I live on the outskirts of 
>Washington, DC and use a Channelmaster antenna with an amplifier.  The 

Your problem isn't that you aren't picking up the signals; you are.  It's
probably that you are picking up too many channels.  I'm in the Tidewater
VA area and have been getting a lot of troposcatter reception recently,
picking up FM broadcast stations as far away as New York City.

If that is indeed the problem, about the only thing you can do is to get
a directional antenna on a rotator, and try to pick out the station you
want.

Of course, you could have a bad connection somewhere, or an amplifier problem.
The strange propagation effects will go away in the winter; an antenna system
problem will stay around until you fix it.  (I know this isn't a terribly
rapid diagnostic method, but it's effective, and frankly there isn't much
good on TV anyway over the summer).
--scott
From: cchapman@matd.gatech.edu (Charles H. Chapman)
Newsgroups: sci.electronics
Subject: Re: M68HC11 info needed
Date: 31 Aug 92 18:29:42 GMT
Organization: Georgia Institute of Technology

In article <1992Aug29.045135.11282@ee.ubc.ca> jmorriso@ee.ubc.ca (John Paul Morrison) writes:
>In article <keb2oo600UhWE8=LEa@andrew.cmu.edu> hk0w+@andrew.cmu.edu (Hanjoon Alex Kim) writes:
>>I have no idea what kind of responses I'll get, since this is my first posting.
>>I am currently working on a project which involves the Motorola 68HC11.
>>Now, I ran into a problem with the Mac. The Mac C compiler for the 68HC11 that
>>I have does not like to divide numbers or deal with floating points. And, 
>>being a student, I don't have the money to buy a compiler that does. Do you
>>know of any solutions to my problem? Maybe a cheap (~$20) compiler out there
>>for the Mac? Or a way around my problem?
>
>The MC68HC11xx series has no math instructions, so the compiler wont do them.
>Someone already sugested calling the Motorola Freeware BBS.
>
>If you have the money for yet another more expensive 6811, you can check
>out the MC68HC711 series (I think it's 711) which has built in math instuctions.
>

Huh??  What is your definition of math instructions?  The 68HC11 has add,
subtract, multiply (and maybe divide, too.  I can't remember) instructions.
These are all integer only instructions but you can certainly use them
as the building blocks for complete floating point libraries.  Heck, I
can run Quick Basic on my 8088 PC with no coprocessor and do all kinds of
transcendental math functions and the 8088 has the same class of math
instructions as the 68HC11, although it uses 16 bits instead of 8.

Chuck

Charles H. Chapman  (GTRI/MATD)             (404) 528-7588
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:     ...!{allegra,amd,hplabs,ut-ngp}!gatech!matd!cchapman
Internet: cchapman@matd.gatech.edu
From: rcook@gfx.engga.uwo.ca (Richard Cook)
Newsgroups: sci.electronics
Subject: Re: Plastic Card HELP
Date: 31 Aug 92 15:43:20 GMT
Article-I.D.: julian.1992Aug31.154320.7051
Organization: University of Western Ontario, London

In article <1992Aug30.150642.1@kosmos.wcc.govt.nz> landall_v@kosmos.wcc.govt.nz writes:
>Hi
>
>Could someone plase tell me how the NZ Phone cards are coded and/or the other
>Plastic Cards with magnetic strips on them.
>
>I would like to make a Plastic Card Reader (NOT A WRITER (Well not yet ;-) )).
>
>Does anyone know how the data is writen on then (ie binary) and how to get the
>data from the card to the serial port?
>
>THANKS in advance...
>-Landall_V@Kosmos.wcc.govt.nz
>

I have found a magnetic card stripe reader in a surplus store,
(maybe from a pay phone).  It had three open collector outputs for
the electric eye (card detect), strobe, and data.

I interfaced these to a parallel input port and played with the
software until the bit stream was repeatable.

A trip to the library turned up the documentation on the data 
format for the financial institutions use of magnetic stripe cards.
This was years ago and I have just recently started looking for it
again myself.

The first library I have been to this week does not have the
publications but did have an index.  Try looking for
ANSI X9.2 or ANSI X4.21 or ISO 7811/2, /4, and /5.

I will have to make a trip to Toronto to find these again.  I am
not sure which one it is.  This standard gives the format of the
first track of the cards.  I have been able to read the number and
expiry date from cards like VISA, American Express, Canadian Tire,
and all banks that I have come across.

The American Express card has a wider stripe and contains 2 or 3
tracks of data.  The other tracks contain the members name and like
information.  My simple reader only access the first track; good
enough to make an electronic combination lock.

Good luck.
		Richard

-- 
Adult Children of Alcoholics:  God, grant me the serenity to accept
 the things we cannot change, the courage to change the things we
             can, and the wisdom to know the difference.
     * Help break the chain; become aware and educate others! *
Newsgroups: sci.electronics
From: rmintz@ecst.csuchico.edu (Rich Mintz)
Subject: Re: Filtering TV Commercials
Organization: California State University, Chico
Date: Thu, 03 Sep 1992 20:32:41 GMT

John:
        I have a technique for blanking out the audio and 
video on commercials that works pretty well under the 
right circumstances if you have a VCR. Using the VCR 
remote control's INPUT SELECT button, where you select 
between normal tv, "simulcast" (where you see the picture 
but the audio is replaced with whatever you feed in the 
AUDIO IN connectors on the back of the VCR), or "line in" 
(where both the video and audio are coming from external 
sources connected up in the back of the vcr).
 
By flipping into this "line-in" mode, you can kill the 
video of a commercial, as well as the audio, via remote 
control if your vcr has one and supports that feature.
 
Starting immediately after the intro song of a program 
ends, I time how long the commercial break lasts. Usually 
it lasts around 2 to 2.5 minutes. With very few 
exceptions (however, I watch very little tv), every 
commercial break will last the same amount of time.
 
So! I have a little batch file on my PC that I have set 
up to automatically delay for the number of seconds I 
specify and to then beep when the countdown reaches 0. 
Another press of the INPUT SELECT button, and *poof* my 
program's back on again and I only had to suffer through 
maybe 3 seconds of commercials 8-)
 
Especially on non-broadcast (ie cable only) networks, 
where I'm PAYING them indirectly through my cable bill to 
watch a channel, it makes me really angry to have 
programming constantly interrupted by those insulting 
screams to "SAVE! SAVE! SAVE! BUY! BUY! BUY! BETTER 
HURRY! NOT MANY LEFT/SALE'S ALMOST OVER!!!!"
 
     Rich -> rmintz@cscihp.ecst.csuchico.edu

Newsgroups: sci.electronics
From: dbowman@shade (Don A. Bowman)
Subject: 100 pin QFP ZIF
Organization: University of Waterloo
Date: Wed, 2 Sep 1992 01:03:20 GMT

I am looking for a zif socket for a 100 pin quad flat pack (normally surface
mounted j-wing device). It has 25 pins on each side. (It is a Toshiba
TMP68303).

Does anyone know where I would go to get such a device?


dbowman@zeus.uwaterloo.ca
From: jmjr@hpcvcbw.cv.hp.com (Jerry Marshall)
Newsgroups: sci.electronics
Subject: MIDI keyboard scanner chip
Date: 4 Sep 92 15:20:29 GMT
Organization: Hewlett-Packard Company, Corvallis, Oregon USA


I am posting this for a friend who cannot access this group.  Please reply
to me via email.  Thanks for any help you can provide.

Jerry Marshall
==============================================================

  Anybody have any idea how I would go about buying some chips from a place
  in England?  I found something on the net that would be perfect for a musical
  toy I want to build.  It's a keyboard (i.e. synthesizer) scanner that outputs
  serial data according to MIDI (the synthesizer standard protocol) specs.
  Sounds like one needs to add a clock crystal and power, and the rest is in
  the chip.  So what's the conversion from "pounds sterling" to US dollarinos?
  Better yet, if anybody has anyway to find out if such a chip is built and
  distributed in the US, that would be great.

  This is it:
  Maplin Electronics
  P.O. Box 3
  Rayleigh
  Essex
  SS6 2BR

  Telephone : 0702 554161
  Fax : 0702 553935
  Telex : 995695(MAPLIN G)
  Cashtel : 0702 552941

  MIDI Device : E510 keyboard scanner for touch sensitive Keyboards
  Page : 422 - 423
  Order Code : KU41U
  Price : 24.95 Pounds sterling

  Description : A fully polyphonic fast keyboard scanner with serial data
  output to MIDI specs. Up to 128 keys can be scanned, each touch
  sensitive with a resolution of 128us (256us with 4MHz clock). 

  Specification

  Supply voltage : 5v +/- 5%
  Supply current : 5mA
  Max clock rate : 8MHz
  Package : 16 pin DIL
Newsgroups: sci.electronics
From: johnwitt@cdrom.engin.umich.edu (John P Wittkoski )
Subject: Minimum speed on processors
Originator: johnwitt@cdrom.engin.umich.edu
Organization: University of Michigan Engineering, Ann Arbor
Date: Thu, 27 Aug 1992 13:57:03 GMT



For a 33MHz 68030, there is a minimum clock speed listed for it in
the databooks. I think it's somewhere around 25Mhz for a 33MHz version, but I
don't have my databook handy.

My question is: why is there a minimum?
One possibility I have heard is that the on-chip registers and/or cache
are dynamic in nature, and since the chip is geared for 33MHz, it divides
this down to whatever rate is needed for the refresh circuitry. Therefore,
if you go below the minimum, the refresh rate slows to below the minimum
needed for the refresh.

Now, is there someone out there who knows about this? I'm interested
specifically in the 68xxx CPUs, but any general info would be helpful.
For example:
1. Is the guess I made above accurate, or is there some other reason?
2. If the reason above is correct, does it apply to the registers, the
   cache, or both (or neither?)
3. If it's just a testing parameter, how far could I crank the clock speed
   down? 20Mhz? 16,8,2,1???

Just curious.
Reply by newsgroup or email, whichever is easiest for you.

        --John Wittkoski
          University of Michigan
          johnwitt@engin.umich.edu
From: micjrs@mica.mic.ki.se (Richard Soderberg, MD)
Newsgroups: sci.electronics
Subject: Gas detection systems
Date: 31 Aug 92 06:51:18 GMT
Reply-To: micjrs@mica.mic.ki.se (Richard Soderberg, MD)
Organization: The Karolinska Institute, Stockholm, Sweden

gas? Are these commercially available? What about CO (Carbon Monoxide) 
detection systems?
Thanx in advance
/RS


#include <standard.disclaimer.h>
Richard Soderberg, MD 
Facsimile:   Int + 46 8 33 04 81
Talk phone: Int + 46 8 728 80 00
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: TV xmission by VHF radio?
Summary: No; it's a matter of bandwidth.
Date: 29 Aug 92 21:25:53 GMT
Organization: University of Georgia, Athens

In article <1992Aug29.192830.844@ddsw1.mcs.com> whos@ddsw1.mcs.com (Ben Feen) writes:
>Here's a scenario:
>A VCR's Video line out is connected to the mic input of a VHF radio xmitter.
>A short distance away, a scanner has its earphone output connected to a VCR's
>video input.
>
>Would this work, and if not, why not?

No; inadequate bandwidth.  The frequency ranges needed for various kinds
of signals are:
         Sound (telephone quality)    300 Hz to 3000 Hz
         Sound (high fidelity)        20 Hz to 20,000 Hz
         Television (low quality)     10 Hz to 2,000,000 Hz (2 MHz)
         Television (US broadcast)    10 Hz to 6,000,000 Hz (6 MHz)
         Thinwire Ethernet            something low to 10,000,000 Hz (I think)

Now you know what bandwidth means: it's the width of the band of frequencies
that must be passed in order to reproduce a signal faithfully.
-- 
+ Michael Covington - Artificial Intelligence Programs - U of Georgia - USA 
+ Unless otherwise noted, these are private opinions, not official statements.
+ VOTE NO GEORGIA LOTTERY - we need not imitate mistakes of other states.
Newsgroups: sci.electronics