HDTenEightyP/NetNews huggingface dataset:
From: nagle@netcom.com (John Nagle)
Subject: Re: Mirror Galvonometer HELP !!!!!
Date: Fri, 14 Aug 92 18:38:12 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

clrmic08@uctvax.uct.ac.za writes:
>I'm busy doing my final year elec eng thesis and I need to get hold of a mirror
>galvonometer or similar device to deflect a laser. It must have a range of at
>least 5 degrees and a bandwidth of about 10 KHz. I can't get hold of this
>device here in South Africa and to import it from the UK will cost about 900
>pounds and that excludes import duty etc etc.

>I am also looking for a laser in the 5 to 20 Watt power range (visible).

        10KHz is faster than ordinary mirror galvanometers will go, even
for small deflection angles.  There are resonant scanners available in
that range from General Scanning Corporation, but they're expensive.
Slow (150Hz) scanners are easily available, though.  Try Silicon Valley
Surplus, 1273 Industrial Parkway W.,  Bldg. 460, Haywood, CA
94544-7025 USA.  Phone 510-582-6602.

         For low-cost lasers, try Meredith Instruments, P.O. Box 
1724, Glendale, AZ, 85301.  Small units with laser diodes in the 5 to 30
milliwatt range are available.  

         If you really want a 5 to 20 watt laser, those too can be
obtained, but they're big, expensive, and moderately dangerous.  You also
need mirrors with adequate power-handling capability.  Do you really need
power in that range?

					John Nagle
From: rkarlqu@hpscit.sc.hp.com (Rick Karlquist)
Newsgroups: sci.electronics
Subject: Re: Why are high frequency transformers small?
Date: 12 Aug 92 16:27:56 GMT
Organization: Hewlett-Packard, Santa Clara, CA

In sci.electronics, bender@oobleck (Duke of Canterbury) writes:

> rkarlqu@hpscit.sc.hp.com (Rick Karlquist) writes:
> : In sci.electronics, kevin@clsi.COM (Kevin Cameron) writes:
> : 
> : 
> : > There are two basic parts to a transformer:
> : 
> : >       1: the windings
> : 
> : >       2: the core
> : 
> : > the actual "transforming" is achieved by coupling between the windings

> Why does an autotransformer, and it's variable cousin, the Variac, work?

> mike

An autotransformer is nothing but a conventional transformer with 
a connection between the primary and secondary.  Coupling between
the windings above the tap and the windings below the tap is just
as important as coupling between primary and secondary of a conventional
transformer.  RF autotransformers tend to work poorly because of
poor coupling between the turns of the coil, especially with an
air core.*  Adding a magnetic core does not increase the absolute
mutual inductance, but it increases the magnetizing inductance so that
the leakage inductance is a smaller percentage of the magnetizing
inductance.  (I.E. it increases the % coupling).

Variacs are a special case because at high voltage settings, the thing
is mainly just a shunt inductor across the line with only a minor
amount of transformer action.  At low voltage settings, where it really
does need to act as a transformer, a lot less power needs to be 
transferred, so it doesn't need to be very efficient.

*See H. Wheeler, Proc. IRE, 1959.


Rick Karlquist 
rkarlqu@scd.hp.com
Newsgroups: sci.electronics
From: zben@ni.umd.edu (Charles B. Cranston)
Subject: Re: A construction question about front panels for home-brew projects...
Followup-To: sci.electronics
Organization: UM Home for the Terminally Analytical
Distribution: na
Date: Sat, 22 Aug 1992 02:09:29 GMT

In article <1992Aug21.012025.13775@pony.Ingres.COM>,
bonobo@Ingres.COM (David Victor) wrote:
 
> I'm trying to make a nice-looking aluminum front panel for a project,
> and I'd like to be able to use rectangular switches, possibly other
> squared-off displays, etc.  How do you cut a perfectly-squared-off hole
> in an aluminum panel?  Is there some home-brew method I'm not aware of?

The best way, of course, is to use a chassis punch.  You drill a hole
(within the final desired rectangle, of course) and thread through the
screw.  Then the screw tightens the knife part of the punch into the
die part of the punch, and cuts the hole cleanly.  The downside is the
expense of the punch itself.

The next cheapest way is to use a "nibbling tool", a hand-operated tool
that "nibbles" rectangular chunks (about 1/4" by 1/10") each time you
actuate the handle.  You drill a hole, within the final rectangle, just
big enough to get the nibbler's head in.  Then you nibble out to "near"
the rectangles boundary, and finish up with a metal file (though
actually after a little practice you can get very precise at the border
by "nibbling" less than a full "bite").  This is especially effective
if you have a bezel to mount around the hole to hide the edges.

I should probably invest in a DB-25 chassis punch, since it is really
tedious making that odd shape with a nibbler...
From: etmfrov@genesis.ericsson.se (Frank Overman)
Newsgroups: sci.electronics
Subject: Intel's 82077SL
Summary: 82077SL
Date: 17 Aug 92 16:37:38 GMT
Organization: Ericsson


Is there anyone out there who has already used or programmed the Intel
82077SL diskdrive controller?

I am going to and I would like to know if there are things I should
think about when using it hardware like and also software like.

-Frank
Newsgroups: sci.electronics
From: R2NVK@VM1.CC.UAKRON.EDU
Subject: logic simulation
Organization: The University of Akron
Date: Tue, 18 Aug 1992 15:45:59 GMT

I am looking for any information regarding shareware programs for logic sim
ulation. Any help would beappreciated.
Please send replies to: r2nvk@vm1.cc.uakron.edu
Thankin you in advance.
From: jsm@shade.Princeton.EDU (John Scott McCauley Jr.)
Newsgroups: sci.electronics
Subject: Maxim ICL7660CPA
Date: 14 Aug 92 16:13:26 GMT
Organization: Princeton University
Originator: news@nimaster

Has anybody used this chip (+5v to -5v converter)? Are protetcion diodes
needed on the Maxim version?

The original Intersil datasheet warns about latchup. The NSC 7660 datasheet
says the latchup is fixed and no diodes are necessary. I can't find a Maxim
datasheet to check.

	Thanks,

		Scott
Newsgroups: sci.electronics,misc.wanted
From: wlee@csd4.csd.uwm.edu (Wan Ngai Wayne Lee)
Subject: Info/data sheet for 8154 wanted
Originator: wlee@csd4.csd.uwm.edu
Organization: Computing Services Division, University of Wisconsin - Milwaukee
Distribution: usa
Date: Mon, 17 Aug 1992 01:54:51 GMT

The 8154 is a 40 pin dip with 128 bytes of ram and two 8 bit I/O ports.
Any programming info or data sheet is appreciated.
================================================================================
      name: Lee, Wan Ngai
      mail: 2121 E. Newport Ave., Milwaukee, WI, 53211
     phone: (414) 963-4157
  internet: wlee@csd4.csd.uwm.edu
compuserve: >internet:wlee@csd4.csd.uwm.edu
From: shawn@panix.com (Shawn Herzinger)
Newsgroups: sci.electronics
Subject: Disabling ringer on a Toshiba EKT6010-S?
Date: 20 Aug 92 21:25:00 GMT
Organization: PANIX Public Access Unix, NYC

Does anyone out there know how to do this?  This is a Toshiba 
multi-line (6 line) Key system.  Each tel. set has an electronic
ringer which sounds through a speaker.  The obvious solution is to
clip the leads to the speaker. But, if I do that, I lose the 
speakerphone etc.  There are two volume controls on the phone, however,
the volume control for the ringer also controls the volume of the
speaker when it is used for the paging intercom.  I looked at the
board and did not see any DIP switches or labled jumpers for turning
off the ringer.

If someone out there has serviced this type of system I would appreciate
some advice.  Thanks.

Please E-mail to shawn@panix.com
From: feiges@cae.wisc.edu (Howard Feiges)
Newsgroups: sci.electronics
Subject: Re: Phone in use light - help!?
Date: 18 Aug 92 20:54:18 GMT
Organization: U of Wisconsin-Madison College of Engineering


Hello there - its feiges here (in reply to the post about the
telephone line protectoer)

Radio shack sels the device for $7.95 (part #43-107)  

its called the tele-protector.........

its in the new radio shack '93 catalog on page 14 


------  if people have been trying to reach me at (feiges@jomby.cs.wisc.edu),
that account was conveiniantly deleted sometime this morning (sheesh) - ---

anyways, please try to reach me at my  CAE account (I hate my CAE account -
but right now its the only one I have) - at:

feiges@cae.wisc.edu

thanx

Howard Feiges

TPK
Newsgroups: sci.electronics
From: dister@tramp.Colorado.EDU (P Disterhoft)
Subject: PC board cost analysis
Organization: University of Colorado, Boulder
Distribution: usa
Date: Thu, 13 Aug 1992 17:48:11 GMT


Anyone know of any published material on 'manufacturing cost analysis of 
PC boards'.  Any source that deals with production or processing costs and
or cost models would be appreciated.

dister@fred.colorado.edu
From: koos@kzdoos.hacktic.nl (Koos van den Hout)
Newsgroups: sci.electronics
Subject: Re: Geometry information for old Tandon drive needed!
Date: Wed, 19 Aug 92 07:45:52  -1
Organization: Koos z'n Doos (BBS)
NewsSoftware: Rnf 0.6b

>  This is a longshot, but here goes:  I have an old Tandon
>hard disk.  It's a 5" form factor, full height, MFM, 30Mb
>(actually formats out to about 33Mb, I believe) capacity.
>  Does anyone recognize this drive ?  Can you tell me the
>geometry ?

Well your longshot works... (or at least seams to work). According to
'TheRef41' there's only one Tandon that has specifications that look like this
one, and they are :

Tandon
Type TM703AT
5,25" FH
733 cylinders
3 platters
5 heads
17 sec/track
31.0 Mb formatted (=32505856 bytes if Mb=2**20)
ST412 interface
MFM encoding
5.0 Mb transfer/sec
40mS avg. seek.

Unless you have formatted an MFM disk with an RLL controller this is the only
harddisk that's close.

I hope this is the correct information.

                                        Grtx. KH

| Koos van den Hout                        Internet koos@kzdoos.hacktic.nl |
| Student Computer Science                   Fido Sysop @ 2:500/101.11012  |
| SysOp BBS Koos z'n Doos (+31-3402-36647)  300/1200/2400N81 ANSI/AVT/TTY  |
| >> International E-mail costs me 10 times as much as a followup ...   << |
Newsgroups: sci.electronics
From: boortz@sics.se (Kent Boortz)
Subject: How slow are halogen lamps?
Organization: Swedish Institute of Computer Science, Kista
Distribution: sci
Date: Fri, 21 Aug 1992 22:56:05 GMT



I have noted that when halogen stage lights go of (500-2000W) there is
a delay before the light is gone. Is the response to voltage changes slow
for halogen lights? I was thinking of controlling a TRIAC with a
microcontroller and one idea is to use patterns of AC half periods that is
on or off. A 50% setting would be one halfperiod (hp) of and one on.
A 75% setting would be 3 hp's on and one off. Switching the TRIAC on and
off at the zero crossing point would eliminate the need for filtering away
unwanted electro-magnetic interference.

The problem is flickering for low settings. A 10% setting will give 9 hp's
off and one hp on. But if the halogen lamp is slow in response it will
eventually be no problem. Anyone know?


Kent Boortz
boortz@sics.se
--
Kent Boortz
boortz@sics.se
From: cpyy@vax5.cit.cornell.edu
Newsgroups: sci.electronics
Subject: Cable Television Descrambling
Date: 14 Aug 92 08:53:14 EDT
Distribution: sci
Organization: Cornell University

Does anyone want to restart an old thread?  How about Cable Television
descrambling in underdeveloped towns (Ithaca, NY for one) ?

-- 

Jon C. Russo
internet : cpyy@vax5.cit.cornell.edu
phone    : 607.277.3295
From: ray@ole.cdac.com (Ray Berry)
Newsgroups: sci.electronics
Subject: Senate bill 1706 bans consultants?
Date: 12 Aug 92 16:05:35 GMT
Distribution: usa
Organization: Cascade Design Automation


	On page 73 of the current issue of Electronic Design (Aug 6th), a reader
asserts that a bill is before the Senate which would prohibit "electronics,
electrical, and computer people from being consultants...".  Has anyone else
heard about this?  Can this be for real?
-- 
Ray Berry  kb7ht  ray@ole.UUCP  73407.3152@compuserve.com  /* inquire within */
From: rcook@gfx.engga.uwo.ca (Richard Cook)
Subject: Re: How can I send a bit to an optocoupler connected tp PC
Organization: University of Western Ontario, London
Date: Fri, 14 Aug 1992 13:52:14 GMT

In article <13AUG199218514852@judy.uh.edu> cscc13@judy.uh.edu (NAVEED IQBAL) writes:
>I want to write a program in C to turn on a relay controlled by an 
>optocoupler. I want to connect the coupler to a Pcs serial/parellel 
>port.
>- What would be the pinout?
>- How can I do that in C?
>  - or another language?
>- I don't want to use those interface boards as I can't afford to.
>
>
>
>Thanx
>Naveed Iqbal
>NIqbal@uh.edu
>
>

I have just finished testing control of a stepper motor through
optocouplers and my printer port.

I used LPT2 in Borland C++; on my computer LPT2 is at address 278,
which is 632 in decimal.  The output port is latched in the PC so
using the following commands will turn on/off the output bit and
leave it that way until you change it, turn off the computer, or
run some other software that uses the printer port:

	outportb(632,1);	/*  set bit 0 to 1  */

	outportb(632,0);	/*  set bit 0 to 0  */

Bit 0 on the parallel port is pin number 2.  (bits 1 to 7 are pins
3 to 9).  All 8 bits are changed at the same time.

I fed pin 2 of a male DB-25 connector to a resistor, of
about 470 ohms, then the resistor to pin 1 of the optocoupler.
Connect pin 2 of the optocoupler to pin 25 of the DB-25.

I found this in an electronics magazine, (Radio Elect. or the like).
If you are interested I will find the reference.

My e-mail address until the end of August is rcook@gfx.engga.uwo.ca

Good Luck


+-----------------------------------------------------------------+
| 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!          |
+-----------------------------------------------------------------+
-- 

+-----------------------------------------------------------------+
| Adult Children of Alcoholics:                                   |
|                                                                 |
From: kolstad@cae.wisc.edu (Joel Kolstad)
Newsgroups: sci.electronics
Subject: Re: new here
Date: 21 Aug 92 01:39:41 GMT
Organization: U of Wisconsin-Madison College of Engineering

In article <23928.2A935A5E@psycho.fidonet.org> Randy.Baer@f310.n3603.z1.FIDONET.ORG (Randy Baer) writes:
>  Just want to say HI..take up a little bandwith for a HOWDY DOODY.
>Hope to be reading and posting here.  Just start my senior yr at the
>local uni  (USF).
>v of tee is equal to L time dee I dee T

Although you do know lots more than that by your senior year, right?  You've
no doubt had the thrill of your life going throw electrodynamics like I
did -- NOT!

(Actually, electrodynamics did eventually get useful... It was a lot of
new math for me, though, which I initially didn't like)
P
From: newsman@milton.u.washington.edu (Chris Ricci)
Newsgroups: sci.electronics
Subject: Voice/Modem Switch
Date: 19 Aug 92 02:49:29 GMT
Article-I.D.: u.1992Aug19.024929.4021
Organization: University of Washington, Seattle

Perhaps I've already posted here.  Perhaps not.  Perhaps I'm just babbling in-  coherently in a bunch of different newsgroups.  If any of these apply I'm sorry.

I am seeking a solution to the following problem.  I am looking for a way to    run a BBS on the same phone line my personal calls come in on(Voice).  Being    the lowly poor college student, I have a limited budget, BUT.... I am a EE      student so I'm not an idiot and I could build a solution.  If anybody out there in computer land knows of any solution(Even one I'd have to build).  Could you  pleeeeeeeeeease... let me know. 

Thank you. Thank you. Thank you.....

Chris 
Newsgroups: sci.electronics
From: mark@lenti.med.umn.edu (Mark Olson (CDC))
Subject: RE: SHOCKING STORIES
Organization: University of Minnesota
Date: Mon, 17 Aug 1992 21:22:48 GMT

   When I (ever so long ago) was in junior high school I built a rudimentary
oscilloscope - it had a 3" screen, the appropriate power supplies, an
audio amplifier and a small piezoelectric microphone.
  
   For some reason I don't understand, the shaft of the focus knob had the
entire G1 voltage present on it - about 40 microfarads of oil-filled
capacitor charged up to 1kv, with a connected power supply capable of
delivering 200ma.  I thought I was safe because there was a bakelite knob
on the shaft - except that the little hex screw affixing the knob to the
shaft wasn't insulated at all... it took about 3 days of playing with this
thing before I finally reached for the focus knob with my right hand while
holding the grounded, metal encased microphone in my left hand.
  
   I found myself laying on the floor about 8 feet from the apparatus, with
deep burns on the thumbs of both my hands - so deep they bled.  The 
microphone cord had broken from my, er, sudden leap backwards, and the
rest of the thing had tipped over on the bench.
  
   After a couple of days had passed I dismantled the 'scope, and almost
got shocked again by the charge left in the capacitor bank.  

   Can't see the scars anymore, but the feeling of 'gee, was I ever lucky'
still remains...

mark olson
mark@lenti.med.umn.edu
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: green screen - sometimes
Summary: How to find a loose connection
Date: 17 Aug 92 01:26:30 GMT
Article-I.D.: athena.1992Aug17.012630.18878
Organization: University of Georgia, Athens

Sounds like the problem is a temperature-dependent loose connection
(maybe inside a component).  You could try shooting freezing spray
(available from Radio Shack) onto various parts of the TV to see if
the problem appears or disappears suddenly when you hit a particular
component.  (Don't spray it onto the glass of the CRT!)  You could
also try warming up various areas and then individual components with
a hair dryer.
-- 
+ Michael Covington - Artificial Intelligence Programs - U of Georgia - USA 
+ Unless otherwise noted, these are private opinions, not official statements.
+ VOTE NO GEORGIA LOTTERY - don't tie education to an unpredictable income.
From: thompson@pyrman2.mis.pyramid.com (David Thompson)
Newsgroups: sci.electronics
Subject: **** PCLAB Data-aquisition boards ****
Keywords: PCLAB A/D D/A DI/O digitizer optoisolator
Date: 13 Aug 92 17:57:36 GMT
Distribution: na
Originator: daemon@sword.eng.pyramid.com



	I have the following IBM-PC compatible cards for sale:


o	PC-LAB model PCL-720 Digital I/O and Counter card.
	32-digital inputs
	32-digital outputs w/high output driving capability
	3-channel programmable interval timer
	Onboard crystal Oscillator clock source
	Breadboard area for customized circuitry.
	Complete with documentation
	Cost 189.00					Sell at 80.00

o	PC-LAB model PCL-711S Data aquisition board
	12-bit A/D input with 8-channel Multiplexer
	12-bit D/A output
	16-digital inputs
	16 digital outputs
	screw-terminal board for A/D & D/A connection
	Labtech Aquire Software for aquisition and display
	C and Pascal drivers for Borland and Microsoft compilers
	Complete documentation.

	Package cost- 450.00					$275.00

o	PC-LAB model PCL-725 Relay actuator and Isolated D/I card
	8 Relays
	8 opto-isolated digital inputs
	LED indicators show activated relays
	Jumper selectable isolated/non-isolated input signals
	Complete documentation.

	Cost 189.00					Sell at $80.00

	All the above are in excellent condition.
	TERMS: COD- You pay shipping / PREPAY- I pay shipping.
	Shipped items must be insured. Shipped Next Day or Second Day
	I can be reached at (408)378-5053 7pm-10pm Pacific time 
	OR EMAIL 
	thompson@pyrman2.pyramid.com
From: dana@locus.com (Dana H. Myers)
Newsgroups: sci.electronics
Subject: Re: How hot can the 486-50 cpu run ?
Summary: Doesn't solder melt below 400 deg C ?
Date: 18 Aug 92 15:12:05 GMT
Organization: Locus Computing Corporation, Los Angeles, California

In article <0095F463.09AD9C00@FHYDRA.FYSEL.UNIT.NO> dahls@fhydra.dnet.unit.no (Joern Yngve Dahl-Stamnes) writes:
>Thus spoke the keyboard of jeremiahw@wl.aecl.ca:
>>I heard that the 486 could get up to 400 deg Celcius if the appropriate program
>>was run (one designed to turn on as many transistors as possible)  I am
>>skeptical about the number 400 but needless to say it does run hot.  Many VARs
>>and OEMs have had problems designing clones simply because of the heat problem.
>
>At 400 deg Celcius the chip won't work very good - if it work at all.
>It depend a bit of how long time the chip is at this high temperature.
>I may work at 400 for a very short time, but not for any long time.

I don't have a reference handy, but I recall that solder melts at a lower
temp than 400 C. I mean, 400C is 750 deg F. 

I can imagine the 486-50 running at 100-120 C, but not 400 C, even briefly.


-- 
 * Dana H. Myers KK6JQ 		| Views expressed here are	*
 * (213) 337-5136 		| mine and do not necessarily	*
 * dana@locus.com  DoD #466 	| reflect those of my employer	*
 * "Dammit Bones, spare me the lecture and give me the shot!"   *
Newsgroups: sci.electronics,comp.sys.mac.hardware
From: fredm@media.mit.edu (Fred Martin)
Subject: PowerBook 100 LCD screen, update 2
Organization: MIT Media Laboratory
Date: Wed, 12 Aug 1992 15:59:34 GMT

In desperation, I took apart the LCD screen unit.  My efforts were
rewarded:  the screen is manufactured by Sharp Electronics!  The part
number is definitely "LM64"; this number is printed on one of the PC
boards inside the screen.

The company name "Fujikura," the only name visible before I took the
unit apart, was printed on the thin ribbon cable that connected the
LCD to the Mac.  A friend of mine looked up the name in an "Electronic
Industry Telephone Directory" and found "Fujikura America" as an
importer.  So maybe they import the screen for Sharp?  I hope not,
because if so, I may be out of luck.

Now, I am anxiously awaiting a call-back from my local Sharp
representative.  

	- Fred

-- 
Fred Martin | fredm@media.mit.edu | (617) 253-7143 | 20 Ames St. Rm. E15-301
Epistemology and Learning Group, MIT Media Lab     | Cambridge, MA 02139 USA
From: v078p6g8@ubvmsb.cc.buffalo.edu (Richard M Wasserman)
Newsgroups: sci.electronics
Subject: motorola hc05 special ?
Date: 19 Aug 92 05:08:00 GMT
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41


	I was wondering ( hoping might be more accurate ) that the hc05
development special might still be in effect - or that someone might be 
interested in selling theirs :-).  Anyway answers either way via mail would
be greatly appreciated.  Thanks in advance.
		Rich Wasserman
Newsgroups: sci.electronics