HDTenEightyP/NetNews huggingface dataset:
From: jjhayes@nbrwh75.bnr.ca (Jeff Hayes)
Subject: Re: EIA-232 cable length restrictions
Reply-To: jjhayes@x400gate.bnr.ca
Organization: Northern Telecom Public Switching, Bramalea Product Tech. S908
Date: Mon, 17 Aug 1992 22:01:58 GMT

well i can only tell you about empirical eveidence.  I ran a multi-user
RSX11m DEC system years ago in a noisy shop floor env and had 3 VT100s
about 150' away from the Mini-box and never a breath of a problem.
So you can push the specs!  but listen for other comments too.

In article <1992Aug17.192021.4354@miles.com>, jep@miles.com (Joseph Perry) writes:
_]I'm trying to determine the maximum cable length for EIA-232 connections.  
_]EIA-232 specifies that the effective shunt capacitance of the receiver 
_]side of the interchange circuit be no more that 2500 picofarads.
_]

-- 

jeff hayes                      ESN 333-3894   phone (416) 452-3894
jjhayes@400gate.bnr.ca          Northern Telecom, Prod Tech, Bramalea Ont
From: mjohnson@netcom.Netcom.COM (Mark Johnson)
Newsgroups: sci.electronics
Subject: Re: Simple transistor project (Q)
Date: 14 Aug 92 00:20:14 GMT
Organization: Netcom Online Communications Service

In the spirit of the poster's first article, the following
discrete circuit will get the job done:

                               +5.0V      +5.0V    +5.0V
                                 |          |       |
                                 |          |       |  minus
            C1                 C |          |      D1
           10uF                 /         relay   1N4148
logic     + | | -         B  | /          coil      |
 in  >------| |-----+--------|  Q1          |       |  plus
            | |     |        | \            +--------
                    |         E \           |
                    R1          |         C /
                    50K         |      B | /
                    |           +--------|  Q2
 Q1 and Q2          |           |        | \
 are NPN            |           R2        E \
 general purpose    |          3.3K         |
 (like 2N2222)      |           |           |
                    |           |           |
                   GND         GND         GND

When the logic signal makes a low-to-high transition,
the base of Q1 rises.  This turns on Q1.  The emitter
of Q1 rises, and that turns on Q2 (energizing the relay).

After a delay equal to (R1 * C1) = 0.5 seconds, the base
of Q1 falls low again, turning off Q1.  This turns off
Q2 and the relay.

Protection diode D1 clamps the inductive back-EMF
induced when the current in the relay coil cuts off
to zero.

TTL compatibility is achieved by setting the turnon
point to 2*VBE (same as TTL).
Xref: sparky sci.electronics:14586 misc.forsale:24036
From: vcb@irk.ugcs.caltech.edu (Vance Carl Bjorn)
Newsgroups: sci.electronics,misc.forsale
Subject: FORSALE: Notebook sized Oscilloscope
Keywords: oscilloscope
Date: 19 Aug 92 14:26:20 GMT
Organization: California Institute of Technology, Pasadena



For Sale
++++++++++++

BBC/Goerz Metrawatt M2050 Digital Scope Multimeter

This is a small, rugged, portable unit that combines the functions
of a digital multimeter, digital oscilloscope and a transient recorder.
It has a flat LCD display screen with a dot matrix of 128x64 for 
displaying voltages and currents as a function of time, and separate
LCD for displaying other information (3.5 digit multimeter, O'scope
setup info, etc)  This is a very rugged unit, made in (West) Germany,
and comes with soft carrying case, two probes and a temperature probe.
The unit runs on rechargable NiCd's and will operate for about 8hrs
when fully charged.  The oscilloscope has a maximum sampling rate
of 512kHz, and has variable zooming and waveform storage cababilities.
It has four triggering modes.  

I used the unit as a wonderful multimeter, that had the added advantage
of having an oscilloscope on it.  It is in perfect condition.

New it was $3000, but my interests and major hace changed, so
I would like to sell it for around $650

Vance Bjorn
vcb@ugcs.caltech.edu
Newsgroups: sci.electronics
From: newsman@milton.u.washington.edu (Chris Ricci)
Subject: Damark catalog
Organization: University of Washington, Seattle
Date: Sun, 23 Aug 1992 00:46:59 GMT

I am looking for the address or the phone number for Damark.  Does anyone
happen to have it.  I would appreciate it.  Thank you!

Chris
From: mjohnson@netcom.Netcom.COM (Mark Johnson)
Newsgroups: sci.electronics
Subject: Re: CMOS Oscillator
Date: 18 Aug 92 22:09:00 GMT
Organization: Netcom Online Communications Service

In article <1992Aug18.140051.10073@donau.et.tudelft.nl> elmar@dutentb.et.tudelft.nl (Elmar van Ginneken) writes:
   > What I am looking for is a low power oscillator (<.5 mA @ 5V) running
   > at a frequency of roughly 1 MHz.
   > However, the frequency-determining component should be an inductor with
   > a value of approx. 75 uH. (YES, I'm trying to measure inductance-change..)

The circuit below uses a single CMOS lowspeed 74C14 inverting Schmitt
trigger chip, your 75uH inductor, and two 10K resistors.  It draws
about 400uA and oscillates at about 4MHz.

The oscillator period will be approximately linearly related to the
inductor value,   Period  ~=~  K1  +  ( K2 * L )   .   Note also that
K1 will not be zero.


                                                         ------------> Output
                                                         |
                                                         |
         |\                |\                |\          |     |\
         |  \              |  \              |  \        |     |  \
         |    \            |    \            |    \      |     |    \
  |------|     >O----------|     >O----------|     >O----+-----|     >O-----|
  |      |    /            |    /            |    /            |    /       |
  |      |  /              |  /              |  /              |  /         |
  |      |/                |/                |/                |/           |
  |                                                                         |
  |                                          +5.0V                          |
  |                                            |                            |
  |                                            \                            |
  |                                            /  R1                        |
  |                              /|            \ 10K                        |
  |                            /  |            /                 L1         |
  |                          /    |            |                75 uH       |
  |------------------------O<     |------------+---+----------)()()()(-------
                             \    |                |
                               \  |                /
                                 \|                \  R2
                                                   / 10K
                                                   \
                                                   |
                                                  GND


--MJ
From: rkarlqu@hpscit.sc.hp.com (Rick Karlquist)
Date: Sun, 23 Aug 1992 03:06:14 GMT
Subject: Re: variable current source
Organization: Hewlett-Packard, Santa Clara, CA
Newsgroups: sci.electronics

In sci.electronics, rcrandall@sc9.intel.com writes:

> In article <92234.103751U09207@uicvm.uic.edu>, U09207@uicvm.uic.edu writes:
> > From: Vahe Caliskan
> > 
> > I am looking for a circuit that can be used to control the current

> > the "handgun" style soldering irons. Anyway, I was looking for a simple
> > 
> > Vahe Caliskan (vahe@uicbert.eecs.uic.edu)

> I would think that a good motor speed controller or variable lamp brightness
> control would work great.  It would not have any temperature feedback, but
> would certainly have some control of the temperature of the tip.  Another
> way of doing it would be to use a ac-dc converter circuit and then use
> a variable current source circuit with thermocouple feedback from the tip
> to get very good control.

> Rob
> rcrandall@sc.intel.com

Soldering "guns" (like the Weller's) have a transformer driven 
heating wire.  You cannot use SCR or TRIAC based lamp dimmers with
transformer driven equipment.

The easiest way to control a soldering gun is to simply use a 
variac on the AC input to the soldering gun.

Rick Karlquist
rkarlqu@scd.hp.com
From: chuck@drutx.ATT.COM (LucianoC)
Newsgroups: sci.electronics
Subject: Re: Laser speed gun detectors?
Date: 18 Aug 92 19:22:50 GMT
Reply-To: chuck@drutx.ATT.COM (LucianoC)
Organization: AT&T, Denver, CO

In article <1992Aug16.173120.10715@cis.ohio-state.edu> rubin@chocktaw.cis.ohio-state.edu (Daniel Rubin) writes:
>Actually, yes there is a laser detector available and the device is
>simpler and cheeper than a radar detector!  Cincinnati Microwave sells
>one for only $99 and it works very well ( from what I have heard I do
>not own one ).  I believe the laser beam is used as more of a scanning
>beam than a single beam so it is fairly detectable.  It would be very 
>hard for a police officer to point a single laser beam at a car moving at
>a high rate of speed.  

I interviewed with a company in Englewood, Colorado that makes these puppys
and after the interview I asked the interviewer if we could take one outside
and play with it. We did, and I can tell you that it has a deadly accurate
sight on it and you could easily target an oncoming car at up to 1/2 mile.
The readout is virtually instantaneous.

I am skeptical about the usefulness of the detectors as they would only work
if someone else was clocked while you and he were both in sight of the cop.

Using the $99 rationale for assuming the laser detector may not be correct,
it may simply be that both cost about the same to manufacture, but who'd pay
$299 for a detector that will almost never save you.

Chuck Luciano
From: MICHAEL.ZACHERL@OFFICE.WANG.COM ("Michael Zacherl")
Newsgroups: sci.electronics
Subject: SONY 3 1/2" /128MB MODs
Date: 21 Aug 92 12:23:19 GMT
Reply-To: mza@pag.wang.co.at
Organization: Mail to News Gateway at Wang Labs

Recently I saw an announcement from SONY's 'new' 3 1/2" /128MB MOD-drives.
The discs look like normal 3 1/2" discs and can be attached via SCSI.
I think the sheet is rather old (maybe outdated??).
I can't recall the modellname, further data and price!
Anyone outthere can send me specific information???

Thanks a lot!

michael
Newsgroups: sci.electronics
From: paigen@tfs.com (David Paigen)
Subject: Re: EIA-232 cable length restrictions
Organization: TRW Financial Systems
Date: Mon, 17 Aug 1992 23:38:29 GMT

I do not claim to be an expert on this, but I thought that I would
throw in a data point.

I used 100 feet of unshielded phone wire (radio shack 22 g.) at 9600
baud with no difficulty.  There were no errors, even while doing file
xfer, no interference from or to the cable.

Well, that I noticed, anyway.

I remember being led to believe, on the basis of a table in the Kermit
book (yellow cover) that I would have spotty results with 9600/100 ft.

----------------------->"Lay on, McDuff,    14th c. ideals in a 21st c. world
David Paigen            and damn'd be he        N: PLO Bush IRA CIA KKK
TRW Financial Systems   who first cries,        S: terrorism pipe bomb kill
paigen@tfs.com          'hold, enough!'"        A: assasination maim
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Anti-consultant bill ??
Summary: Senate 1702 isn't it.  What is?
Date: 19 Aug 92 17:49:35 GMT
Organization: University of Georgia, Athens

Re the bill mentioned recently in Electronic Design that would "outlaw
private consulting,"

Senate 1702 (which unless I've miscopied it is the number they gave)
is not it.  Senate 1702 removes the import duty on three industrial
chemicals that I'd never heard of, and does nothing else.

Does anyone have a correct bill number for this thing?  Is it real at all?

-- 
+ 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: drp40@cd.amdahl.com (Douglas R Puchalski)
Newsgroups: sci.electronics
Subject: Filtering wind noise
Date: 13 Aug 92 18:38:20 GMT
Reply-To: drp40@cd.amdahl.com
Organization: Amdahl Corporation, Sunnyvale, CA

I'd like to be able to use two-way radios for skydiving.  Problem
is, 120mph of wind hitting up against a microphone would probably
mask out any voices.  Anyone have any ideas of how to get around
this?

-- 
Doug Puchalski						drp40@cd.amdahl.com
From: evansmp@uhura.aston.ac.uk (Mark Evans)
Newsgroups: sci.electronics
Subject: Re: Electronic device after nuclear war
Date: 12 Aug 92 17:06:38 GMT
Organization: Aston University

john@anasazi.com (John R. Moore) writes:
: In article <1992Aug4.193044.12259@newstand.syr.edu> amichiel@rodan.acs.syr.edu (Allen J Michielsen) writes:
: >In @news.acns.nwu.edu> tilden@casbah.acns.nwu.edu (Robert Tilden) writes:
: ]>	The scenario I've seen for a pre-emptive EMP strike has a huge
: ]>(50-100 megaton) device being detonated 50 miles over, say, Nevada. The EMP
: ]>would be sufficient to damage equipment over the western 1/3 of the U.S.
: ]
: ]  Let's take a reality check here...  A device as you describe, would do the
: ]damage you describe (in all probability).  However, that 1/3 of the U.S. would
: ]have a much greater problem than TV's not working.  The population of that area
: ]would be very sick, with fatality rate of something like 80% in 3 weeks.  While
: This is nonsense. Such a blast would have NO significant health effects 
: (except for those who were watching the blast and were blinded).
: 
: Remember, EMP is electromagnetic pulse, not ionizing radiation. It is
: unlikely to hurt anyone.

Not quite correct, though biological systems are much less sensitive to
this than electronic ones.
(Though if you were close enough to the blast to be affected by the EMP then
you would most likely be with in the area affected directly by the blast)

There are of course secondary risks in the suggested senario,
for people using telephones, etc. or in fly by wire aircraft.
-- 
-------------------------------------------------------------------------
Mark Evans                                   |evansmp@uhura.aston.ac.uk
+(44) 21 565 1979 (Home)                     |evansmp@cs.aston.ac.uk
+(44) 21 359 6531 x4039 (Office)             |
From: then@vipunen.hut.fi (Tomi  H Engdahl)
Newsgroups: sci.electronics
Subject: Solder melting point (was Re: How hot can the 486-50 cpu run ?)
Date: 19 Aug 92 20:17:05 GMT
	<0095F463.09AD9C00@FHYDRA.FYSEL.UNIT.NO>
	<1992Aug18.151205.2809787@locus.com>
Organization: Helsinki University of Technology, Finland

In article <1992Aug18.151205.2809787@locus.com> dana@locus.com (Dana H. Myers) writes:

>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. 

My reference says that the solder melts in temperatures between 188C and 
220C. For eaxample Multicore 60/40 melts at 188C. Multcore Savbit melts at
215C.

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

I think that over 200C is too high for silicon chips.


--

Tomi.Engdahl@hut.fi            "Don't force it; get a larger hammer"
then@vipunen.hut.fi                        
Newsgroups: sci.electronics
From: pegasus@csd4.csd.uwm.edu (David R Hucke)
Subject: DS5000 question
Originator: pegasus@csd4.csd.uwm.edu
Organization: Computing Services Division, University of Wisconsin - Milwaukee
Date: Fri, 14 Aug 1992 01:38:41 GMT

Hi everyone:

Got a question or two about an 8051 problem (DS5000 actually).

I have an LED hooked up to P0.0 through a PNP transistor buffer.  This
part is fine.  I have a a resistor (330 Ohms) hooked up to P0.1 which can
be set to ground of +5v.  

Below is my program,  it should do the following,  

	1)  Turn of the watchdog timer  (disable it).
	2)  Enable P0.1 as an INPUT by writing a 1 to it.
	3)  Turn off the LED at P0.0
	4)  When P0.1 goes high, the LED should light up.
	5)  When P0.1 goes low, the LED should turn off.

This is not what is happening.  What is happening is that the LED never
turns completely off and the LED sometimes lights up when I put P0.1 to
ground.  After about approx 5-10 seconds,  I have to reset the DS5000 to
get any results at all.  And sometimes the LEDs turns on and off rapidly.
Generally speaking, the results seems to be quite random.

Could somebody tell what could be wrong either with my program, hardware, or 
both?  Note:  My DS5000 is rated at 12 Mhtz, but I have it running at 8 Mhtz.


======  Program begins here ========
.org 0
anl h'087, #b'11111011 ;;;  Turn Watchdog off

setb P0.0       ;;  Turn LED on
setb P0.1 	;;  P0.1 is now an INPUT
sjmp loop
RING:
		;;  clr P0.0; Turn LED on.
   cpl P0.0     ;;  P0.0 = NOT P0.0  
   ret
NORING:
		;;  setb P0.0; Turn LED off.
   cpl P0.0     ;;  P0.0 = NOT P0.0
   ret

loop:
   jnb P0.1,RING
   jb P0.1,NORING
   acall loop
.end

==== End program  ====

Thank you very much.

--
pegasus@csd4.csd.uwm.edu
-- 
pegasus@csd4.csd.uwm.edu                David R. Hucke
                                        UW-Milwaukee Film Major
--
From: aviz@lanai.cs.ucla.edu (Dr Algirdas Avizienis)
Newsgroups: sci.electronics
Subject: Microcontrollers
Summary: microcontrollers - how to
Keywords: Microcontroller help info
Date: 12 Aug 92 14:42:54 GMT
Distribution: usa
Organization: UCLA Computer Science Department

Hello!

I am interested in using a microcontroller (such as the Motorola
68HC11 or the Intel 8051) in my next project, however, I know very
little about either of these chips, and I'm not sure where to start
looking.  I'm looking for more than just a data sheet.  Some sort
of book or magazine article would be nice.

Please reply by e-mail.  Thanks a lot/
Newsgroups: sci.electronics
From: rcrandall@sc9.intel.com
Subject: Re: variable current source
Organization: Intel CTD
Date: Fri, 21 Aug 1992 17:18:28 GMT

In article <92234.103751U09207@uicvm.uic.edu>, U09207@uicvm.uic.edu writes:
> From: Vahe Caliskan
> 
> I am looking for a circuit that can be used to control the current
> delivered to a soldering iron tip from the ac line. The tip is not a
> regular heating element as in hand held soldering irons but it is the
> wire type found in
> the "handgun" style soldering irons. Anyway, I was looking for a simple
> circuit employing SCRs, Triacs, Diacs that can do the job. I am trying to
> control the current from 3 to 8 amps. Any suggestions? Please email to me.
> Any help would be greatly appreciated since I am not very familiar with
> circuits that use the above mentioned devices.
> 
> Thanks in advance.
> 
> Vahe Caliskan (vahe@uicbert.eecs.uic.edu)

I would think that a good motor speed controller or variable lamp brightness
control would work great.  It would not have any temperature feedback, but
would certainly have some control of the temperature of the tip.  Another
way of doing it would be to use a ac-dc converter circuit and then use
a variable current source circuit with thermocouple feedback from the tip
to get very good control.

Rob
rcrandall@sc.intel.com
From: "ian tuck" <ian.tuck@canrem.com>
Newsgroups: sci.electronics
Subject: laser speed gun detec
Date: 21 Aug 92 02:04:44 EST
Reply-To: "ian tuck" <ian.tuck@canrem.com>
Distribution: sci
Organization: Canada Remote Systems

JN>       Anyone know what they're using as a detector?  I'm building a laser
JN>rangefinder for robot vision, and I'd like to know what these guys use.
JN>PIN diodes don't put out much output and avalanche diodes are too nonlinear
JN>for use when the beam is dimmer than the ambient light.  So what do they
JN>use to get that kind of S/N?

Just in case yer wonderin', July's IEEE Spectrum has an article on the
new laser radar detectors.  No mention of detection schema, but it uses a
pulsed-radar principle.  It transmits a burst of pulses over a few 10ths of
a second, then does a regression analysis on the measured delays.  From what
I could glean from the article, however, the down-the-road laser cannot
(unlike normal radar) be used in moving mode.  Hope this helps.
Ian
---
  DeLuxe/386 1.25 #8528  
--
Canada Remote Systems  - Toronto, Ontario/Detroit, MI
World's Largest PCBOARD System - 416-629-7000/629-7044
Newsgroups: sci.electronics
From: newsman@milton.u.washington.edu (Chris Ricci)
Subject: Modem/Voice switch
Organization: University of Washington, Seattle
Date: Sat, 15 Aug 1992 22:25:23 GMT

Forgive me if this message is posted twice.  I am seeking a voice/modem phone   switch.  If one cannot be found for cheap I am willing to build one.  Does      anybody know where I could find one or the plans for one.  How much do they     cost?  

Chris.
From: cam@castle.ed.ac.uk (Chris Malcolm)
Newsgroups: sci.electronics
Subject: Re: Filtering wind noise
Date: 14 Aug 92 15:19:37 GMT
Organization: Edinburgh University

In article <dfAW02=71de601@JUTS.ccc.amdahl.com> drp40@cd.amdahl.com writes:

>I'd like to be able to use two-way radios for skydiving.  Problem
>is, 120mph of wind hitting up against a microphone would probably
>mask out any voices.  Anyone have any ideas of how to get around
>this?

	1) A throat mike under clothing.

	2) Use combined ear speaker/mike, inside substantial ear muff.
	The voice gets to the ear via head transmission.
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205
Newsgroups: sci.electronics
From: markz@ssc.wa.com (Mark Zenier)
Subject: Re: Programming 68705P3
Organization: SSC, Inc., Seattle, WA
Date: Wed, 12 Aug 1992 06:17:02 GMT

In article <2A86F013.2535@noiro.acs.uci.edu> gkwan@balboa.eng.uci.edu (Greg Kwan) writes:
>In article <1992Aug08.194203.15660@ssc.wa.com> markz@ssc.wa.com (Mark Zenier) writes:

>>  (Trick number 1, the chip's eprom erases to
>>(as I remember) 0, and any unused bytes in the image should be the
>>same value, as the boot rom skips programming those.  Much faster.)

>Actually all unused bytes should be $FF.

No.  Zero.  I had to look at 3 different books before I found this
in the 1984 spec. sheet.  It's not in the latest Microprocessor 
Databook I have, nor in the old Users Manual.

>FWIW: I bought (10) of the P3 parts for $6 each but recently saw an 
>ad in _Nuts and Volts_ selling them for $2.95 ea. Other (hobbyist)
>sources sell 'em for ~$12-15. They are easier to obtain than Mot's
>HC05 family.

Vetco (the Seattle areas newest and only remaining electronic surplus 
store) 206-869-7025.  I bought a tube full there, but havn't had time to 
check them out.

Mark Zenier  markz@ssc.wa.com  

From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Thu, 13 Aug 1992 20:24:42 GMT
Subject: Re: Re: RGB leds - they're need but who makes them
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: sci.electronics

> >  I recently got a LEDTRONICS catalog listing an rgb led that when 
> >connected properly will produce a white light...
> 
> Do bear in mind that you're not going to get an awful lot of white
> light out of it, because today's blue LEDs are not very bright.
> -- 

The blue part doesn't have to be as bright as the red and green - the usual
mix of green, red, and blue to produce white is approximately 60/30/10%,
respectively.  In other words, the blue LED can be 1/6 as bright as the green 
and 1/3 as bright as the red, and still get acceptable white.  (Unfortunately,
the brightest LEDs around are red, not green, but you can always turn the
red down a bit....)


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   User Interface Tech. Div.|those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.
Newsgroups: sci.electronics