HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.electronics
Subject: DC power connectors
From: Mike_Dewit@kcbbs.gen.nz (Mike Dewit)
Date: 18 Dec 92 04:52:59 GMT
Organization: Kappa Crucis Unix BBS, Auckland, New Zealand

           ____________________________________________________
          |_________________ inside of shell makes contact with| 
                               outer surface of plug shroud    |
            ________________|                                  |----
  ---->    (________________| centre pin, 2.5 or 1.1 mm        |cord
plug goes                   |  diameter to fit hole in plug    |----
in thus    _________________                                   |
          |____________________________________________________|
             cutaway view of inline socket
 
This drawing is supposed to show a connector, of the type that is 
commonly used on small DC power supply adapters, for things like 
personal stereos and suchlike. The plugs have an outside dimension of
about 5.2 mm (0.2") and a hole in the centre of either 1.1 or 2.5 mm.
The plugs are easy to get, and so are the sockets that are used in the
small DC powered devices, that is the PCB or panel mounting types. 
What I need are the CORD MOUNTING SOCKETS, which I have one (1) of.
It is the opposite sex to the type that is always fitted to these
"plug-pack" transformer power supplies, and has a plastic screw-on back
cover/body, like the common plug does.
 
If anyone knows where these can be bought (in 100 quantities),
please post, or email me ( Mike_Dewit@kcbbs.gen.nz ). Thanks.
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
From: byron@cc.gatech.edu (Byron A Jeff)
Subject: Re: Query: What are pseudo-static RAMS?
Reply-To: byron@cc.gatech.edu (Byron A Jeff)
Organization: Georgia Institute of Technology
Date: Fri, 18 Dec 1992 19:03:17 GMT

In article <5150067@pollux.svale.hp.com> ryoung@pollux.svale.hp.com (Roderick Young) writes:
>Psedostatic RAMs are not truly static, because (in some cases), they can
>be "busy" refreshing while you want to access data.  Also, they tend to
>be slower than true static RAM.

That's not my understanding now. The Pseudo-statics I have seen have to be 
explicitly refreshed by pulling OE low. This fortuatly is easily done by
the microprocessor using the part. And the best thing is the long (very
long) refresh interval of 32 ms for 2048 rows. That's only 3 times a second.
>
>As for power, they do pretty well, but I wouldn't expect one to retain
>data at 2V and a few microamps.

That's true, but the tradeoff of 5V at 200 uA is good enough for me.

>
>If you're building your own project, and access time is not an issue, then
>PS RAM might be a convenient way to go (saves a DRAM controller).  However,
>for commercial applications, there's only a narrow range of uses that justifies
>the PS price (vs. dynamic).

The convenience is marked. DIP packaging, simple refresh protocol, and 4x
density over statics. If you had told me I could get 512K x 8 in a 32 pin
DIP two months ago for $27 I would have told you that that's impossible.
I find them amazing. And with the rising cost of DRAM, PSRAM is starting
to look pretty darn good.

BAJ
---
Another random extraction from the mental bit stream of...
Byron A. Jeff - PhD student operating in parallel!
Georgia Tech, Atlanta GA 30332   Internet: byron@cc.gatech.edu
Newsgroups: sci.electronics
From: frank@rover.uchicago.edu (Frank - Hardware Hacker - Borger)
Subject: Re: Voltage regulators in parallel?
News-Software: VAX/VMS VNEWS 1.41    
Reply-To: frank@rover.uchicago.edu
Organization: Joint Center for Radiation Therapy
Date: Thu, 17 Dec 1992 16:17:00 GMT

In article <9212170609.AA07808@gaak.LCS.MIT.EDU>, jpexg@gaak.LCS.MIT.EDU (John Purbrick) writes...
> 
>I want to set up a power supply delivering more current than an integrated
>voltage regulator (LM78xx if fixed, or LM317 if variable) will provide. It
>seems valid to parallel as many of the relevant component as I need to get
>the current; certainly they won't all pass the same current, and the voltage
>out will drop if the initially-highest regulator starts to overload, but it
>should settle to some lower voltage as other regulators start to conduct 
>more. It seems that this would apply whether the overload was caused by 
>overcurrent or overheating. And when all the regulators are conducting, the 
>output should be no lower than the lowest output would have been if they were 
>wired individually.
> 
	The technique works well, but you need two things additional.

	A/ You need what are called ballast resistors to balance the current
	   delivered by each regulator. Typically you should have something
	   on the order of 0.5 volts or so drop in each resistor at full
	   current. (Note that this requires a regulator that lets you use
	   a remote voltage sensing point.)

	B/ It's a good idea to add a fuse in the output of each regulator,
	   so that if one regulator shorts, it doesn't take the rest out with
	   it.

	For the case where load was reasonably constant, I would just figure
	each resistor for a 0.5 volt drop, then put a diode between the
	normally grounded pin of the 3-pin regulator. The nominal 0.5 volt
	drop in the diode would make up for the 0.5 volt drop in the ballast
	resistors. For highly varying loads, use an appropriate zener and
	resistor to bias the normally grounded pin of the regulator.

   Frank R. Borger - Physicist    __       Internet:  Frank@rover.uchicago.edu
Michael Reese - Univ. of Chicago |___      Phone : 312-791-8075 fax : 567-7455
  Center for Radiation Therapy   | |_) _   In the first place God made idiots.
                                   | \|_)  That was for practice. Then he made
    "Birthplace of Softball"          |_)  school boards. - Mark Twain
From: gw214790@LANCE.ColoState.Edu (Galen Watts)
Subject: Re: Handling CMOS
Date: Sat, 12 Dec 1992 18:31:00 GMT
Organization: Colorado State U. Engineering College

In article <1992Dec11.211003.22990@pts1.pts.mot.com> more_da@pts4.pts.mot.com writes:
>In article 30773@yuma.ACNS.ColoState.EDU, gw214790@LANCE.ColoState.Edu (Galen Watts) writes:
>>The way I install CMOS chips is in the bathroom.  Take the circuit board, all
>>the tools you might need and the chips into the b-room and close the door.
>>Run the shower on HOT for a few minutes, until the mirror fogs over.  Leave the
>>The idea is to use the high humidity to dissipate any static charges.  
>>
>This isn't a flame or anything, but are you serious?  Boy, am I glad I live in
>sunny and humid South Florida, because I would hate to take a shower everytime
>I play around with CMOS parts.  :-)
>I guess a simple ground strap doesn't suffice up there, huh?
>
Yes, totally serious.  Currently (11:30 am), the temp here is -4c and the
relative humidity reads around 4%.  I don't have a humidifier in my heating
system, but some around here do.  You walk 10 feet across a carpet and touch
the stove or a doorknob and you get a little zap.  Petting the cat or dog in
the dark gives quite a little electrical show, with different colored sparks.
This can be enough to destroy a $20 CMOS chip and I don't take any chances.

As for a ground strap, unless you spend real money for a real strap, they are
pretty much worthless.  I've worked for electronic manufacturers around here
that use CMOS, and they blow about 3-5% of their chips on the assembly line.

The low humidity may be a hassle in the winter, but when summer hits, (90-100F)
it's nice and warm and virtually never "muggy".

It works for me.
Galen Watts, KF0YJ


Newsgroups: sci.electronics
From: mellob@warren1c.its.rpi.edu
Subject: EDUCATION
 
 I think Mr. Kolstad has hit the nail right on the head.
  	We have learned and practiced prolifically throughout
	the eighties, the method of "passing the buck." You can't
	blame it on the schools. You can't teach someone who doesn't
	want or know how to learn. The educatioal problems of this
	nation, in my opinion, start at a very early age in the home.
	When children are impressionable, they should be encouraged
	to learn and to develop a curiousness about the world aruond him/her.
Reply-To: mellob@rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy, NY.
Date: Sat, 12 Dec 1992 20:46:53 GMT

 As for the japanese school system, I, like Joel, don't think i would
	particularily enjoy it there. All hard work and little play
	makes me cranky and not WILLING to learn. This is the impression
	I get of Japanese and Chinese school systems.

 Does anybody know anything about the German school system? A freind of mine
	spent some time in school in Germany and told me that they were
	"wicked smart", mostly because of the competetiveness of the students.

 Not to say that competetiveness among students can't become excessive. I
	have been told (rumors?) that at MIT one time, a student asked his
	roomate for help on a specific problem. The roomate refused simply
	because he felt he was in serious competition with everyone else.

 When the Buck finally stops goin round, we'll be able to see where the real
 problem lies.
			-BRETT MELLOR
 

	
 
	
Newsgroups: sci.electronics
From: boortz@sics.se (Kent Boortz)
Subject: Re: Making decals on plastic
Organization: Swedish Institute of Computer Science, Kista
Date: Wed, 16 Dec 1992 00:32:36 GMT



One way to make black plastic decals with white text is the following:

- Print out the text/graphics on transparent film on a laser printer

- Go into a darkroom

- Take a plastic (not real paper) photo paper for plack and white photos

- Put the transparent film on top of it and turn some light on it
  (can't give you the time, it was many years since I did this)

- Process it as ordinary photo papers


/kgb
--
Kent Boortz
boortz@sics.se
Xref: sparky sci.electronics:21095 rec.aviation:17545
Organization: University of Maine System
Date: Friday, 18 Dec 1992 09:47:26 EST
From: Robert A. Sobczak <SOBCZAK@MAINE.MAINE.EDU>
Newsgroups: sci.electronics,rec.aviation
Subject: Re: Walkman Modification
Distribution: usa

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?
>
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
standing on top of the tx'er to get anything on the FM radio, that is
off tuned by 2-5 khz depending on the radio.

I wish I had better news for ya.

Rob
Newsgroups: sci.electronics
From: pecampbe@mtu.edu (Paul Campbell)
Subject: Re: Please help: clock doubling
Keywords: freq, digital, doubling
Organization: Michigan Technological University
Date: Tue, 15 Dec 1992 01:10:00 GMT

In article <1992Dec14.054100.13939@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>Phase-locked loop with divide-by-2 in the feedback loop?
>74HC4046 and a flip-flop, perhaps...

Too complicated. If you just want to double a digital clock, use an inverter
to create a pulse with a positive or negative edge. Then use a short time
RC network to reset a flip flop. Since you only need pulses anyway, trigger
the circuit on both the positive and negative going pulses and you got
yourself a frequency doubler. If you actually want 50/50 duty cycle, then
the PLL route is the best way to go.

An example of triggering on both pulses is in Art of Electronics, but I don't
have my copy with me, so I can't draw the circuit out without some effort.
Wasn't too complicated as I remember anyways.
From: adrian@cs.hw.ac.uk (Adrian Hurt)
Newsgroups: sci.electronics
Subject: Re: Various national colour code of wires (e.g. earth) for elec. plug
Date: 14 Dec 92 13:33:35 GMT
Organization: Dept of Computing & Electrical Engineering, Heriot-Watt University, Scotland

In article <519@bit.UUCP> grego@bit.UUCP (Grego Sanguinetti) writes:
>In article <6912@otc.otca.oz> brendan@otc.otca.oz (Brendan Jones) writes:
>>Well, many variations on a theme have been posted here, but the complete
>>answer has yet to be posted.  I have recently got an Electrician's license
>>so I can wire my own home, so I feel I am in a position to comment :-)
> ...
>
>Anybody reading sci.electronics should have more than enough basic knowlege
>to figure out house wiring.

Perhaps not - just because one subscribes to a newsgroup does not mean that one
knows as much as the rest of the readers of that newsgroup.  Otherwise, the
only question on the application form for that electrician's licence would be
"How would you subscribe to the group sci.electronics?"  :-)

>Anyway, the color codes you described are unfortunately opposite US N.E.C.
>codes and are therefore very dangerous to use.

That's probably because Brendan, judging from the "In article ..." line, is
in Australia.

I have a little booklet which has a table of international standards for
electrical wire colours, and which is probably only meant to refer to
appliance wiring rather than building wiring.  Most countries seem to use
black or brown for line, blue for neutral and green and/or yellow for
earth.  Canada and the USA are listed as using white or grey for neutral.
The old U.K. (and perhaps Australian) scheme of red for line, black for
neutral and green for earth is not listed.

But the real jokers in the pack seem to be Japan, Greece and Switzerland.
Apparently, Japan uses black for line, white for neutral and red for earth -
is this true?

The entry for Greece says that earth is yellow, neutral is grey, and line
is anything else except blue.  Switzerland seems to have different rules
for 2-wire and 3-wire cables.  3-wire cables use the standard brown line, blue
neutral, green+yellow earth.  2-wire cables use anything except yellow and blue
for line, and anything except yellow and red for neutral.  Would someone who
has seen a Swiss plug please confirm or deny this?

Anyway, the best general rule seems to be - there isn't one!  Learn the
specific rules for the country in which you are wiring, or from which an
appliance came.

-- 
 "Keyboard?  How quaint!" - M. Scott

 Adrian Hurt			     |	JANET:  adrian@uk.ac.hw.cee
 UUCP: ..!uknet!cee.hw.ac.uk!adrian  |  ARPA:  adrian@cee.hw.ac.uk
From: cstadbg@csv.warwick.ac.uk (Mr M J Brown)
Newsgroups: sci.electronics
Subject: Re: FLYWHEELS
Date: 18 Dec 1992 13:42:59 -0000
Organization: Computing Services, University of Warwick, UK
NNTP-Posting-Host: clover.csv.warwick.ac.uk

In article <10310@ncrwat.Waterloo.NCR.COM> tjgerman@53iss6.Waterloo.NCR.COM (Trevor German) writes:
>
>	I have been following the thread about exploding flywheels and 
>	would like to make the following contributions.
>
>	1. Yes, when a fly wheel lets go or is suddenly stopped for some
>	   reason, a hell of a lot of energy is available in a very short
>           period of time. Unimpeded, these flywheel bits can do a lot
>	   of harm. Testiment to that is a machine shop in the steel works
>	   in Hamilton Ontario where a grinding disk exploded killing one
>	   guy and leaving a neet line of holes in the walls and roof.

Show of hands....who's heard the one about the hard disk (I mean the
*ORIGINAL 5 foot diameter) platter escaping!! Nasty, specially at that sort
of speed!

=============================================================================  
     _/      _/   _/   _/  _/   _/_/_/_/   |
    _/_/  _/_/   _/   _/_/     _/          |         Michael Brown
   _/  _/  _/   _/   _/       _/_/         |
  _/      _/   _/   _/_/     _/            |   cstadbg@csv.warwick.ac.uk
 _/      _/   _/   _/  _/   _/_/_/_/  _/   |     mjb@dcs.warwick.ac.uk
                                           |    csulo@csv.warwick.ac.uk
=============================================================================
Newsgroups: sci.electronics
From: jtaylor@dseg.ti.com (Jeff Taylor)
Subject: Re: Who knows TMS320C40 ?
Organization: Texas Instruments, Incorporated
Date: Fri, 11 Dec 1992 18:26:36 GMT

In article <1992Dec11.154233.28261@informatik.uni-wuerzburg.de> koeth@winx06.informatik.uni-wuerzburg.de (johannes koeth) writes:
>From: koeth@winx06.informatik.uni-wuerzburg.de (johannes koeth)
>Subject: Who knows TMS320C40 ?
>Date: Fri, 11 Dec 1992 15:42:33 GMT
>
>I am searching for information about the Texas Instruments DSP TMS320C40 ?
>
>Does somebody have adresses or ftp-sites for me ?
>
>
>                 Thanks
>

You could try the TI Customer Response Center @ US 800-336-5236, ext. 3531
or the TMS320 DSP Hotline @ US 713-274-2320.

I don't know of any E-Mail addresses, sorry.

JTAYLOR@DSEG.TI.COM
Newsgroups: sci.electronics
From: miked@syscon.rn.com (Mike DeMetz)
Subject: Re: Request: Low power op-amp suggestions
Organization: Syscon Corporate Headquarters - South Bend, IN USA
Date: Fri, 11 Dec 1992 20:38:53 GMT
X-Newsreader: TIN [version 1.1 PL6]

I think the LM351 is designed for low power operation.
From: t-huynh@digsol.jpunix.com (tony huynh)
Newsgroups: sci.electronics
Subject: active audio crossover circuits
Date: Sat, 12 Dec 92 15:35:57 CST
Organization: Digital Solutions, Inc. Houston, TX.

Does anyone out there have any information about designing crossover 
circuits (at the audio line level)????  I'm not yet proficient with this 
sort of thing yet, and would like some help.  I've seen circuits using 
IC's like the LF347 etc., but just need to know how to wire it for a
desired cutoff frequency/slope.
 
Thanks -
Tony Huynh
Newsgroups: sci.electronics
From: josemj1@aplmail.jhuapl.edu (Marshall Jose)
Subject: Re: Very sharp RF notch filter sought
Followup-To: sci.electronics
Organization: JHU-Applied Physics Laboratory
Date: Wed, 16 Dec 92 17:44:34 GMT

In article <1992Dec14.064445.9591@ips.oz.au>, bruce@corona.syd.ips.oz.au
           (Bruce Paterson) wrote:

> I need a VERY sharp notch filter (or actually 3, if sharp enough) to reject
> FM broadcast stations from an antenna signal. The requirements are tough:
> a. VERY sharp - I need to measure spectra of broadband noiselike signals and
> the present LC filters make a far too visible hole.
> b. No other holes (or even ripples) in the pass band - 57 to 180MHz.
> c. Low loss.

I live in a rural area where my distant, favorite FM station is wiped out
by a nearby station. The solution I found most promising was written-up
in the August 1991 issue of RF Design, "VHF Active Bandpass Filters", by
Eugene Mayle, pp. 58-65. I haven't had time to try it out yet.

Mayle discusses the use of a grounded-gate JFET as a "Q multiplier". (This
is almost anachronistic since most of us hams thought Q multipliers died
a peaceful death 30 years ago). At any rate, the performance of circuits he
presents in his article are quite remarkable, with one stage typically
capable of a Q of 1,000; this corresponds to a bandpass filter bandwidth
of 0.1%.
Your requirement should be easily met, since this corresponds to a 100 kHz
notch at 100 MHz.

The notch is obtained by paralleling one of his bandpass filters with a
broadband phase-shifting network. At the center frequency, the two
networks' phases cancel. He claims 50 dB notch depth is routinely
achieved. The 200 MHz notch filter he demonstrates shows a <2 dB insertion
loss in the passband.

My concern is that his filters are operating on the fine edge of
oscillation, and might need to be compensated for changes in temperature.
I haven't tried them, so I don't know.  If they do work, though, they would
be a substantial improvement over the two or three large canisters which
would be necessary for a resonant cavity solution.

In regard to the "open-stub" notch that someone else suggested, I suppose
it is something inexpensively verified, although my calculations told me
that the notch width will be too broad for the application. It will remove
a TV channel but will obliterate a large portion of the FM broadcast band

Marshall Jose
josemj1@aplmail.jhuapl.edu
Newsgroups: sci.electronics
From: ankleand@mtl.mit.edu (Andrew Karanicolas)
Subject: Re: Flywheel batteries as EV power source
Organization: MIT Microsystems Technology Laboratories
Date: Sat, 19 Dec 1992 06:52:54 GMT

In article <Bz6nuM.LCo@acsu.buffalo.edu> v064mb9k@ubvmsd.cc.buffalo.edu (NEIL GANDLER) writes:
>
> I just have finished reading the latest Popular Science issue. Jan 93.
>On p. 27 they discuss flywheel power as a possible energy source for 
>future Ev's. Claimed advantges are a cruising rnage of over 600 miles
>on an overnight charge on GM's Impact. With a battery weight of only
>600 pounds and a life of 25,000 miles and with no chemical waste when
>disposed this new power source could revolutionise the
>EV industry. Why is this technology not being looked into more. What
>are the dissadvantages. What is this technology exactly. How is
>mechanical energy stored in such great amounts. Also the IEEE spectrum
>also touched slightly on this topic I believe in their assesment on
>EV development. 
>
>		Neil Gandler


I read a similar article in IEEE Spectrum recently.  The flywheel can
store a lot of energy because of the omega^2.  The idea is to spin the
flywheel very fast.

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.

-- 
Andrew Karanicolas
MIT Microsystems Technology Laboratory
ankleand@mtl.mit.edu
Newsgroups: sci.electronics
From: rrhoades@cs.umr.edu (Ron Rhoades)
Subject: LCD vendors
Date: Sun, 13 Dec 1992 02:03:39 GMT
Distribution: usa
Organization: University of Missouri - Rolla
Originator: rrhoades@mcs213j.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


Newsgroups: sci.electronics,sci.energy
From: pngai@adobe.com (Phil Ngai)
Subject: Re: Flywheel Failure
Organization: Adobe Systems Incorporated
Date: Fri, 18 Dec 1992 21:34:37 GMT

In article <57411@olivea.atc.olivetti.com> fredl@strobe.ATC.Olivetti.Com (Fred Leffingwell) writes:
>	So Is the real reason for not storing energy in a flywheel
>	the danger?  If so why the comments that the things simply
>	fail in a cotton candy like fluff?

Ah, the fluff argument again.

Would you agree that a gas is even less dangerous than cotton candy?

Now, let me expose you to a blow torch. It's only hot gas, right?

-- 
My opinions are my own.

Xref: sparky sci.electronics:20961 sci.energy:6193 rec.autos.tech:16805