HDTenEightyP/NetNews huggingface dataset:
From: philip@next.csc.cuhk.hk (Philip Leung)
Newsgroups: sci.electronics
Subject: NiCad Battery and Environmental Protection
Date: 28 Aug 92 03:48:45 GMT
Organization: The Chinese University of Hong Kong
X-Useragent: Nuntius v1.1

Hi, has anybody heard of any environmental protection action against the
use of NiCad battery at national or international level?  Or is it just
the opposite - battery should be rechargeable and reusable?  A friend of
mine with no network access just asked me this question.  You see, I am
totally new to this.  Please enlighten.
Newsgroups: sci.electronics
From: macucci@ceg.uiuc.edu (Massimo Macucci)
Subject: Re: That Magic TV screen
Organization: University of Illinois at Urbana
Date: Sun, 23 Aug 1992 20:55:09 GMT

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".

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

>Anyway,might any of you folks out there know what the screen is mad
>e out of?

>I would like to try this myself,but dont feel like paying the $49.95.

>They must have confidence in the product,since it has a 5 year war
>entee.


>Thanks.
>-- 
>Aaron Barnes
>aj008@cleveland.freenet.edu
>Part 15 will take over broadcasting one frequency at a time!
>Howard Phillips for President!

I saw one of these things several years ago: they are just Fresnel lenses,
hold at a certain distance from the screen by a plastic or metal frame.
The overall result is extremely poor: you can watch it only from a direction
perpendicular to the lens, otherwise the geometric distortion is intolerable.
Even from right in front of the lens the outer areas of the image are 
affected by both geometric distortion and chromatic aberration. The chromatic
aberration is very severe for a Fresnel lens, because, by design, it
works as a real lens only for one wavelength.
The brightness, as you say, is reduced by the amount corresponding 
to the enlargement of the image, plus the amount due to the imperfect
transparency of the lens, plus a loss connected with the diffraction
efficiency of the Fresnel lens.
In summary, with such a gadget you will see bigger, but with far lower 
quality and only from straight in front of the screen. 
The price ($49.95) doesn't sound particularly good for a plastic Fresnel
lens. About the 5 years warranty I can only say that there are many 
companies which sell useless stuff and offer such warranties: after many
items have been returned they still make a profit out of the ones which 
were not returned because customers were too lazy to do it or even liked
what they had purchased.
If you really want to try it, I would suggest to get a Fresnel lens from
some optics company, I guess it shouldn't be difficult to find one for
significantly less than $49.95. Before ordering the lens, however, 
some math will be needed to determine the focal lens appropriate for 
this application.
					     Massimo Macucci
					     macucci@pimic.iet.unipi.it
					     macucci@gate.spg.uiuc.edu
From: Aki_Mimoto@panam.wimsey.bc.ca (Aki Mimoto)
Newsgroups: sci.electronics
Subject: Z 80
Distribution: world
Date: 3 Sep 92 09:36:14 PST
Organization: Commodore Computer Club / PaNorAmA

 I was wondering, i wanted to use Z 80 pu to , drive a alphanumeric lcd
dispay, and have a keyboard, (just the minimum amount of keys) hooked up.
How is it done and how difficult would it be. I haven't been able to find
any documentation anywhere


-- Via DLG Pro v0.992

Newsgroups: sci.electronics
From: dbowman@shade (Don A. Bowman)
Subject: Re: Stepper Motor Control
Organization: University of Waterloo
Date: Wed, 2 Sep 1992 23:01:05 GMT

root@drdhh.hanse.de (Bjoern Kriews) writes:
: Short question:
: I want to drive a fourphase 12V stepper motor from a 5V HCT latch.
: Is it possible to use a simple NPN transistor and to connect
: the motor common lead to 12V instaed of ground ?
: 
: Will the stepper run with reversed coils ?
: I'll try out but I'd like to know if I do big big NONO's :-)
: 

This should work fine, but I would instead use a N-channel mosfet
(IRF510 perhaps). These have the advantage of using no input current,
and will saturate more easily.

Stepper motors are indestructible if you don't exceed the maximum current
Reversing the coils is harmless.


-- 
Don Bowman                (519) 744-6154     dbowman@zeus.uwaterloo.ca
From: mm@mentor.cc.purdue.edu (Mike MacKenzie)
Newsgroups: sci.electronics
Subject: Re: Old laser rejuvenation
Date: 26 Aug 92 21:23:41 GMT
Distribution: usa
Organization: Purdue University

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.
> 
> >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.)
> 
> You have lost the gas. You woudln't expect helium gas stays in the 
> tube forever?
> 
> Peace and Prosperity!
>   ---==< 110 >==---

While loss of gas will change the tube running voltage, it's unlikely
that it would lase after losing that much gas.
When a laser has lost its helium, the plasma when viewed from the side
will be brillian neon orange.  A properly functioning HeNe will be orangish
yellow. A tube that has taken in air or water will be purple.

I've seen ballast resistors open before.  This would cause the symptoms
you describe, because the voltage will rise until it can arc over the
gap in the resistor, but the power supply can't sustain that voltage.  A
good ballast resistor will be around 50K to 150K ohms.


Michael MacKenzie	(Purdue University Unix Group)
mm@mentor.cc.purdue.edu
Newsgroups: sci.electronics
From: peterwu@microsoft.com (Peter Wu)
Subject: who sells countdown timer?
Date: 27 Aug 92 15:26:58 GMT
Organization: mc
Distribution: usa

I've been looking for a countdown timer to control electric appliances
for years but found none. The features I need are

- controls appliance (e.g. ni-cd battery charger)
- count down adjustable from 1-24 hours, preferably keypad input

This is similar to a darkroom timer but with much longer time.

If you know where I can buy something like this, please email me.
Thanks.
From: ame@matt.ksu.ksu.edu (Abdulrahman M El-Koubysi)
Newsgroups: sci.electronics
Subject: need some TDA1520Q
Date: 26 Aug 1992 16:52:21 -0500
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu
Summary: I need to find somebody who has or sell TDA1520Q.
Keywords: power amplifier, TDA1520Q,


I am looking for some "TDA1520Q". It is a 20 watt hi-fi audio power amplifier.
Signetics does not make them anymore and I can not find a place that carry them.
Is there somebody out there who can help me find a supplier or may be has some
extras and want to sell them. I need 4 of them. Thankyou


A. R. El-Koubysi          | Internet: ame@matt.ksu.ksu.edu
College of Engineering    | Bitnet  : ame@ksuvm
147, Seaton Hall, KSU     | Phone   : (913) 532-5580 
Manhattan, KS 66506       | Fax     : (913) 532-6944
From: wellison@kuhub.cc.ukans.edu
Newsgroups: sci.electronics
Subject: Re: Old laser rejuvenation
Date: 27 Aug 92 16:49:05 CDT
Organization: University of Kansas Academic Computing Services


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.

My largest HeNe is a Jodon 1575 which is 35mW and circa 1967. Believe it or
not, it still works just fine. It's a big sucker though :-) It has a dual
filament, which I thought was rather strange to begin with, as moderen HeNe's
don't have filaments, but one had burned out and the University tossed it out.
So I rescued it out of the dumpster and took it home. I simply changed the
filament lead to the secondary filament and she works fine (about 32mW output).
With the cost of HeNe's so low, it might be better just to replace the tube
rather than to mess with trying to re-gas it. But I like one posters idea of
filling a garbage sack with He and sticking the tube in it for a few days. I'll
have to try that just for the fun of it !
					
-=-=- Wes =-=-
Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: Amperage meaning?
Organization: San Diego State University
Date: Tue, 25 Aug 1992 22:12:01 GMT

In article <1992Aug25.192312.22175@javelin.sim.es.com> pashdown@javelin.sim.es.com (Pete Ashdown) writes:


>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

Let me tel you this: do you know that your car battry can supply like 300 
ampers if it is needed, but doesn't do any damage to your car radio! Having 
more supplied current to a device is like going to "all you can eat" place, 
any device draws as much current as it needs, but you can not under supply 
the current.

The maximum power which can be delivered by your transmitter is when you 
apply the maximum rated _voltage_ to it, iff (if and only if) there would be 
a direct connection from supply to the power stage. And no, you are not 
better off bying another PS.


Peace and Prosperity!
  ---==< 110 >==---
From: jpt@uh.msc.edu (Joseph Thomas)
Newsgroups: sci.electronics
Subject: Looking for info on Control Module Inc. barcode reader
Keywords: barcode wand reader cmi
Date: 1 Sep 92 17:47:16 GMT
Distribution: usa
Organization: Minnesota Supercomputer Center, Minneapolis, MN


	I have a barcode reader module for which I have no info or
docs. Is anyone familiar with something made by Control Module Inc. ??
It has a label on the top/front which reads "82500083\n Bar Code Reader\n
87/122 Keyboard" but may have been add somewhere else. One end reads
"Wand Module Model 2063" and has a DIN style connector. The other end
has 3 rj45 jacks labeled RDR, CTRL, and KBD. Does anyone know what any
of these pinouts are ?? Thanks.



Joseph Thomas                           E/Mail:  jpt@msc.edu
Minnesota Supercomputer Center          AT&T:    +1 612 626 0286
Minneapolis, MN                         FAX:     +1 612 624 6550
Newsgroups: sci.electronics
From: xrsbg@calvin.gsfc.nasa.gov (Steve B. Green)
Subject: Looking for a telephone security device
Organization: NASA Goddard Space Flight Center, Greenbelt MD
Date: Wed, 2 Sep 1992 14:42:33 GMT

I am looking for a device that will alert me if another telephone
extension is picked up.  I dont need an un-defeatable circuit, just
something that will work in the average home.  I know RS used to sell
such a device but I cant seem to find one.  I would greatly appreciate
any pointers to ready made or home brew devices.  Thank you.

Preferably, please respond via e-mail to xrsbg@dirac.gsfc.nasa.gov.
--
-- 
Steve Green <xrsbg@charney.gsfc.nasa.gov>

NASA, Goddard Space Flight Center, Centers For Computational Sciences, Code 931
Newsgroups: sci.electronics
From: schumach@convex.com (Richard A. Schumacher)
Subject: Suggested references on AC motors and controls, and generators?
Organization: CONVEX Computer Corporation, Richardson, Tx., USA
Date: Tue, 1 Sep 1992 23:51:35 GMT
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

Something on the handbook level would be more helpful than a fundamental
text on rotating machinery, but all opinions are welcome.
From: tomb@hplsla.hp.com (Tom Bruhns)
Newsgroups: sci.electronics
Subject: Re: Stepper Motor Control
Date: 3 Sep 92 00:27:59 GMT
Article-I.D.: hplsla.5170219
Organization: HP Lake Stevens, WA

gude@uniwa.uwa.edu.au (David J W Emrich) writes:

(about driving a stepper; winding ct to +V, sides to NPN's)
>reversed! The only thing to watch is that you put swamping diodes
>across the NPN transistors, so that back- emf from the coils doesn't
>shoot them!

But you should return the diodes to +2V, at least (and have
transistors that will stand off that voltage).  You want to
change direction of the current as fast as you can for fast
stepping, and a diode directly across 1/2 the winding will
keep current going in that winding for some time.  Also, if
there is transformer action between the two halves of the
winding, the newly-on transistor will be trying to drive
current into that diode, if it's returned to +V, and make 
the transistor's collector current higher than you planned 
(possibly by quite a bit!).
From: duncan@ravel.ati.com (Jim Duncan)
Newsgroups: sci.electronics
Subject: Re: Need info on Power Inverters & why some devices dont like sq waves
Date: 30 Aug 92 05:10:36 GMT
Reply-To: duncan@ravel.ati.com (Jim Duncan)
Organization: KUFX 94.5 FM Stereo, San Jose, CA 'The Fox'

In article <1992Aug27.221155.19203@midway.uchicago.edu> gary@midway.uchicago.edu writes:
>
>Anyone got the scoop on power inverters?
>
The square wave types are generally inexpensive, simple, reliable, and
efficient.  The relatively fast rise time may cause buzz in some
sensitive audio circuitry.

The biggest problem that arises when a square wave feeds ordinary
linear power supplies is that with the significantly lower peak
voltage of the non-sine wave input, the equipment power supply
rectifier-capacitor combination will produce a much lower voltage.
Sometimes, a subsequent regulator may then not see a sufficient
input-output differential.

Generally, if equipment having a linear power supply will work down to
90 VAC sine wave input (test with variac), then it will do fine on a
square wave inverter.

At KUFX, I have three Tripplite SPS units which blast square waves into
the main air studio and engineering room equipment for up to one hour
twenty minutes if the power fails.  It works perfectly; we don't even
get any buzz on the microphones.  You know the time is up, however, 
(besides looking at the battery voltmeters I supplied) when an
increasingly loud hum/buzz appears on the air - linear regulators
giving up.   
-- 
KUFX |      w  ["]                            | WA6MBV     
94.5 |...   |___|_____..duncan@ravel.ati.com  | Jim Duncan  
FM   |          H                             | ----------   
********  \_____I_____/  37 3 10N/121 59 10W  ************** 
Xref: sparky sci.electronics:15196 alt.guitar:7741
Newsgroups: sci.electronics,alt.guitar
Subject: Re: Building effects units for guitars
From: Michael.Bremford@comp.vuw.ac.nz (Mike Bremford)
Date: Fri, 4 Sep 1992 00:36:42 GMT
Organization: Dept. of Comp. Sci., Victoria Uni. of Wellington, New Zealand.


Well, I'll give the advice I was given.
Find a book called 'Electronic Projects for Musicians' by Craig Anderton
(Probably in your local library) Has lots of little boxes, some of them useless
but some are quite good, eg Compressor/Limiter, Some sort of box which can be
configured as a Waa pedal, a 'Tube-type' fuzz box... can't remember the rest.
Worth a look.
	Cheers... Mike
Newsgroups: sci.electronics
From: blanchard@utkux1.utk.edu (Tommy Blanchard GRA|GM)
Subject: Re: Questions about Dolby Surround Sound and Pro Logic
Organization: Chemistry Department, University of Tennessee
Date: Wed, 26 Aug 1992 11:43:08 GMT

In article <912@emoryu1.cc.emory.edu> splee@gnu.ai.mit.edu (Seng-Poh Lee) writes:

>Can anyone provide me with the difference between plain old Dolby Surround
>Sound and Dolby Pro Logic?

>Also, what is the basic technique used by each system?

>Thanks a lot

>--
>Seng-Poh Lee    <splee@gnu.ai.mit.edu>

In the August 1992 issue of Stereo Review, they provide explanation of the 
differences. It seems that Pro Logic is a more advanced method of decoding 
the "surround sound", and adds a center channel extraction and separation-
enhancement circuits. This was taken from an article in Stereo Review. As 
for the second part I do not know. I hope someone can provide a better 
explanation. Hope this helps a little.
From: mcbride@cs.arizona.edu (Chris M. McBride)
Newsgroups: sci.electronics
Subject: PAL vs NTSC
Date: 27 Aug 92 04:47:54 GMT
Organization: U of Arizona CS Dept, Tucson


   I aplogize, I am not a regular reader to this newsgroup, but 
several people told me to bring up my problem here. Please reply via Email
 
I purchased a PAL computer. So I immediately hooked it up to my NTSC 
equipment, and checked it out. My programs ran fine, but there was no
colour. Several people said that the problem is a difference in the
colour encoding between the two systems. So I am wondering what I
should do next? Should I buy a PAL monitor? If so do I need to run
50 hz through it, or can I run 60? What is the easiest way to get a
PAL montior? Is there a cheaper route? Like building some kind of
aparatus between my PAL computer and NTSC montior? Are there any
montiors that can display both systems?
 
Thanx for any help
 
Chris

Newsgroups: sci.electronics
From: jvp@juliet.ll.mit.edu ( Jim Pieronek )
Subject: Re: Does 74LS88 Exist
Followup-To: sci.electronics
Organization: M.I.T. Lincoln Lab - Group 43
	<1992Aug24.185634.17279@kodak.kodak.com>
Date: 26 Aug 92 10:14:04

ornitz@kodak.kodak.com (Barry Ornitz) writes:

   The 7488 is a 256 bit (32 X 8) ROM.  To the best of my knowledge, it was never 
   made in any versions other than the standard TTL 7400 variety.  I remember the
   7488 was used in the bootstrap loader for the Data Generl Nova minicomputer.
   Likewise, I believe the 7407 is available only in conventional TTL.

I missed the original posting on this topic.  I assume it is a
response to a request for a substitute for the 74LS88.  I have used the
Signetics S82S123 successfully as a replacement for the 7488.  Same
pin-out and bit order as I recall.

-Jim

--
-----------------------------------------------------------------------
J.V. Pieronek                           Internet: jvp@ll.mit.edu
M.I.T. Lincoln Laboratory               (617) 981-3468
Lexington, Massachusetts  USA
From: geb1@ra.msstate.edu (Granville Barker)
Newsgroups: sci.electronics
Subject: CATV DECODERS ???
Date: 2 Sep 92 21:40:02 GMT
Organization: Mississippi State University

Can anyone explain how these Scientific Atlanta Cable boxes can talk 
back to the cable company?  Also I see these "TURN-ONS" in R-E for certian
cable boxes, do they really work??

geb1@ra.msstate.edu
From: vcb@irk.ugcs.caltech.edu (Vance Carl Bjorn)
Newsgroups: sci.electronics
Subject: FORSALE: TI C30 DSP C Compiler and Assembler
Keywords: dsp c compiler development
Date: 28 Aug 92 22:24:06 GMT
Organization: California Institute of Technology, Pasadena


I recently acquired the TI C30 C compiler and assembler package
for MS-DOS and OS/2 based machines.  The project which it was for
was not to be.  I have not sent in the registration card yet,
so if there are any recent updates they would be sent free of charge.
I am lowering my price to $600, but I will not go much lower than that;
I will find some use for the package if need be.

Vance Bjorn
vcb@ugcs.caltech.edu
From: sergei@upenn5.hep.upenn.edu (Sergei Borodin)
Newsgroups: sci.electronics
Subject: Re: multi-standard VCR`S (Re: NTSC to PAL Did anyone try? )
Date: 2 Sep 92 17:19:22 GMT
Organization: University of Pennsylvania

In <1992Sep2.103956.14680@lmpsbbs.comm.mot.com> michaelr@ecs.comm.mot.com (Michael Roetzer) writes:

>Where can you buy or mail order multi-standard VCR`s ?  And how much are they?
>Last year I asked in several electronics and video shops in Tucson, AZ about those VCR`s but they
>never heard of it.

>     Michael

  I bought mine (Sharp VC780) in Chicago in some Asian region.
I bet you can do the same in any fairly big city (like LA, NY,
SF). The bad thing about this multistandard equipment is that
 it's from a  gray market, so don't expect USA warranty. 
(But so far mine works fine). 
I paid $392 including tax. (4 head VCR , but nothing "on-screen)
 I've also seen ads in Video Review about multistandard eq.


  S.B.
Newsgroups: sci.electronics
From: aduell@nyx.cs.du.edu (Tony Duell)
Subject: Re: "Chip chat" AY-3-1015
X-Disclaimer: Nyx is a public access Unix system run by the University
	of Denver for the Denver community.  The University has neither
	control over nor responsibility for the opinions of users.
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Sun, 23 Aug 92 18:07:52 GMT


The short answer is no, you can't replace the AY-3-1015 with a 16450
directly.
The long answer is that there are 2 different flavours of UART. 
a) The stand-alone type, designed to be used directly in hard-wired TTL
logic circuits, not necessarily including a microprocessor. These devices
have separate data lines for Transmitt and Receive, Error flags brought
out to pins on the chip, pins for selecting parity/stop/word length etc.
Typeical examples are the AY-3-1015, AY-5-1013, 6402, etc. These tend to
be pin-compatable (although some require a -12v supply on pin 2)
b) The microprocessor bus type. These have an (8-bit) data bus, address
lines, read/write signal, etc and are designed to be linked to a
microprocessor. The word length/stop/parity is controlled by internal
registers, addressable by the microprocessor. Similarly the error flags
are read as bits of an internal register. Typical examples are
PC-compatable family - 8250,8250A,16450,16550
Others - 8251,6850,6551,Z8530,Z8030, etc. In general, these are neither
pin or software compatable.
-tony 'PDP11 Hacker' Duell
ard@siva.bris.ac.uk