HDTenEightyP/NetNews huggingface dataset:
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: Simple transistor project (Q)
Date: 18 Aug 92 00:11:17 GMT
Organization: ISC - Bunker Ramo, Spokane, WA

In article <1992Aug17.122438.20238@donau.et.tudelft.nl> knop@dutecag.et.tudelft.nl (Peter Knoppers) writes:
>>Or, you could capacitively couple the trigger signal.  Saves some gates,
>>if you don't get them for free.
>
>That may create a signal that rises above the VCC level or drops below the
>GND level. Such a signal may trigger a parasitic thyristor in the chip that
>short-circuits the power supply pins and subsequently destroys the chip,
>the power supply, or both.

Do 555's have parasitic thyristors?  Bipolar or CMOS version?  Anyways,
proper sizing of the trigger cap, perhaps some series resistance and
maybe even a diode clamp couldn't hurt. 

>The signals on input pins of most digital chips may NEVER exceed the range
>of the power pins (GND to VCC) by more than about 0.5 Volts. Permanent
>damage may occur if this rule is violated.

A 555 is (by every measure I've heard) an _analog_ component.  Who knows
what evil little tricks lurk inside it, or just how it's fabricated. 
The part has been (ab)used by industry for years, in all manner of
applications, many of which it is ill-suited for.  I'd still look
into the approach, rather than throw another gate package into a
design.

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			"PC's --- the junk bonds of the computer industry"
Newsgroups: sci.electronics
From: byron@cc.gatech.edu (Byron A Jeff)
Subject: GAL Programmer using 68HC705K1 - UPDATE
Reply-To: byron@cc.gatech.edu
Organization: Georgia Institute of Technology
Date: Thu, 13 Aug 1992 18:15:31 GMT

I received quite a few responses on my previous post on building a GAL
programmer. Some of it is relevant to a large group of folks so I'm posting.

1. Elektor Electronics info

   Old Colony Sound Lab
   P.O. Box 243
   Peterborough, NH 03458-0243
   Phone: 603-924-6526 or 6371
   Fax: 603-924-9467

   They accept VISA and Mastercard orders over the phone and will also
   take a personal check by mail.

   The GAL programmer is in the April and May 1992 issues. Back issues
   are $4 apiece.

   There is also a PC board and software for use with an PC through the
   parallel port.

2. Serial communications using 68HC705K1

   To my total surprise I was able to get 9600 BPS communication using
   this microcontroller. It doesn't currently function in full duplex
   mode but for my programmer I don't need it to. I have to add the caveat 
   that it'll probably be difficult to do anything while transmitting 
   or receiving a character at that speed but if you need a 'get info -
   do stuff - give response' loop then this is the way to go.

3. 22V10 and 20V10 GAL programming info

   A big zero so far. Does anyone have any information on the programming
   of these parts? I have a 22V10 from Lattice and programming it is high
   on my priority list.

4. Software

   I received suggestions to call National Semiconductor and get their
   demo OPAL Jr. software (which is the same software package in the
   Elector disk). Also there seem to be some source code copies of palasm
   out on the net. Any other suggestions greatly appriciated.

5. And Finally - a FLAME

   This is for the one person who suggested that I'm wasting my time and
   that I should just get the the Elecktor kit. I work on projects like
   this programmer because I am a hobbyist. This means:

   1. Having understanding of what's going on is more important than
      the final result.

   2. By having my own design and software I can expand or modify
      my design at any time. The Elector kit doesn't (and never will)
      do GALs bigger than 20V8.

   3. By having my own design I can stretch the limits of the application.
      For example this programmer will be connected to a DECstation and
      can be migrated to any platform I have instead of just being stuck
      on a PC.

   The bottom line is that I'm not a sheep. I like to roll my own stuff and
   push projects in new a interesting directions. So give the "just follow
   the experts like sheep" line a break. Nothing ventured, nothing gained.

Keep throwing suggestions (positive ones only please) my way,

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: keithl@klic.rain.com (Keith Lofstrom)
Subject: HP test equipment, laser printer manuals - easy to get
Organization: KLIC
Date: Tue, 18 Aug 1992 19:28:24 GMT

Hewlett-Packard test equipment manuals can be easily obtained by calling
1-800-227-8164 with your credit card handy.  I ordered manuals for some
15 year old pulse generators;  HP does a "print on demand" which took 4 days
from order to delivery.  The person who took the order was knowledgeable,
friendly, and took as long as it took to get the order right.  The manual
prices of $24 and $36 for the two mid-sized operator/service manuals included
shipping (they offered ground but actually shipped 2nd day air).  

Another Useful Note:  If you have an older laser printer, such as the
original Apple LaserWriter, based on the Canon CX engine, you may have
discovered that you can't get hardware service manuals from Apple or
Canon (or Imagen or QMS or Taleris, probably).  You CAN get a manual
for the HP 2686A LaserJet (PN 02686-90920) which covers the hardware
and the print engine electronics (if the Apple CPU board goes out, you
are still out of luck).  You can then order print engine parts from HP,
or Canon, or in some cases find similar parts on PC-25 copiers.

I have no connection with HP besides being a satisfied customer, and working
for one of their competitors for 18 years.  I think their good service deserves
a mention.  Similar services for Tektronix manuals are provided by a retired
employee who is considered an irritant and not allowed in the plant.

Keith
-- 
Keith Lofstrom         keithl@klic.rain.com       Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Power ICs
Newsgroups: sci.electronics
From: technews@iitmax.iit.edu (Kevin Kadow)
Subject:  Where I can I buy a 8-pin Mini Din cable?
Organization: Technology News, IIT, Chicago, IL
Date: Fri, 21 Aug 92 05:14:16 GMT

I've found 8-pin MINI-DIN female PCB mount sockets for my project, but I
have had no success located Male - Male cables for these. Noboby seems to
carry even male inline plugs so I can make my own.

(Please reply via E-mail, I will be packing all my electronics tonight for
the move onto campus)
-- 
Newsgroups: sci.electronics
From: newsman@milton.u.washington.edu (Chris Ricci)
Subject: Voice/Modem Switch
Organization: University of Washington, Seattle
Date: Wed, 19 Aug 1992 04:54:31 GMT

OK I got a message saying my last message was garbled.  Let me know if there
is a problem with this one.  I've changed editors.

I need any ideas anyone might have for a method of using one phone line for
both voice communications and a BBS.  We've been banging our heads trying to
come up with an inexpensive solution.  I am an EE student so I could build the
necessary solution if I had to.  Please e-mail ANY ideas you might have.

Thank you. Thank you. Thank you.

Chris

Newsgroups: sci.electronics
From: jpotter@stsci.edu (Jeffrey J. Potter)
Subject: LM8360
Organization: Space Telescope Science Institute
Date: Fri, 21 Aug 1992 06:39:53 GMT


Hi all!

Does anyone have any information on the LM8360, 40 pin dip?

Thanks!

-- 
-------------------------------------------------------------------------------
Jeffrey J. Potter  |  Space Telescope Science Institute  |  CAUTION:
jpotter@stsci.edu  |          Baltimore Maryland         |  Work in progress! 
-------------------------------------------------------------------------------
Newsgroups: sci.electronics
From: Josef Moellers <mollers.pad@sni.de>
Subject: Re: Guided Vehicles
Date: Thu, 13 Aug 1992 14:07:06 GMT
Organization: Siemens Nixdorf Info.Sys. AG, Paderborn, Germany

In <kwilli.2@elaine.ee.und.ac.za> kwilli@elaine.ee.und.ac.za (KEVIN WILLIAMS : THIRD) writes:

>I am currently investigating circuitry to provide automated guidance to a 
>model car by means of a wire taped to the floor carrying some high frequency 
>signal which is detected by sensors on the car. This is used to provide 
>steering information etc.

>Does anyone know if this is the best way of doing this? If anyone has tried 
>this, I would really like to know about some of the problems or successes 
>you've had!

I can think of two other ways:

One is used by a German company that manufactures model building kits
for model railroads, Faller. They use an iron (or any othe ferro-magnetic
material) wire and a little magnet below the cars to do the steering. I
think it is done completely mechanical.

The other would be by using some contrast-coloring of the path and then
use reflective opto-couplers. If the track is broad enough to reflect
(or absorb) the light of two couplers, then two is enough (if the left
one changes, it means You are heading too much to the left and vice
versa). If the track is not broad enough, use three and try to keep the
middle one on the track using the outer onse to detect which side You're
heading.

The last technique is used by robots on factory floors. It is robust
enough to survive short defects in ths track. You can do splits by
"telling" Your car to keep left/right if everything fails, You can use
more-or-less small defects to convey information, etc.

Using high-frequency might get You in trouble with FCC.

>Thanks!!!
-- 
| Josef Moellers		| c/o Siemens Nixdorf Informationssysteme AG  |
|  USA: mollers.pad@sni-usa.com	| Abt. STO-XS 113	   | Riemekestrasse   |
| !USA: mollers.pad@sni.de	| Phone: (+49) 5251 835124 | D-4790 Paderborn |
Newsgroups: sci.electronics
From: kolstad@cae.wisc.edu (Joel Kolstad)
Subject: Re: Why are 8 bit TTL binary counters so hard to find???
Organization: U of Wisconsin-Madison College of Engineering
Distribution: na
Date: 13 Aug 92 23:18:32 CDT

In article <JON_SREE.92Aug13214342@world.std.com> jon_sree@world.std.com (Jon Sreekanth) writes:
>
>Why is it important to get an 8 bit counter in one package, as 
>opposed to tying two 4-bit counters together ? 

Here's a good reason: 'Cuz I want to be able to preset it to some number.
Recently I needed 2 12 bit counters (16 would have been even better, but
12 sufficied)... and, of course, nobody makes a double 4-bit (or single 8-bit)
pressettable counter.  Yes, I know this would need >20 pins, but that's OK --
there are already 22 pin .3" parts out there!

You're right that a PAL/GAL/etc. would work, but I ended up using 6 74LS161s
instead... 6*.40=2.40 is much cheaper than 3*(>$2)!

						---Joel Kolstad
 
Newsgroups: sci.electronics
From: stirling@mullet.gu.uwa.edu.au (Stirling Hamersley)
Subject: Laser speed gun detectors?
Organization: University Computer Club --- Perth, Western Australia
Date: Fri, 14 Aug 1992 04:43:43 GMT

The local police have taken to using speed guns that use
a laser to determine car speed to catch those with 
the ye olde radar detectors.  Must have been easier than
outlawing radar detectors as they have done in NSW.

Someone told me there are already laser detectors
around.  Is this true and how do they work?  I imagine
the would not be very effective as the laser beam used
to detect the speed is very directional and should only need
to be on for a fraction of a second, once the car has 
been sighted.  Radar detectors depend on detecting when a
car ahead of your car is being gunned.  I can't see you detecting
the laser until it is too late.

"Speed limits are for Volvo drivers" - Hamersley.
From: krueger@cal.enst.fr (Martin Krueger)
Newsgroups: sci.electronics
Subject: Re: "Super-CD" ... soon ?
Date: 17 Aug 92 08:39:35 GMT
Organization: Telecom Paris

In article <713851648snx@black.demon.co.uk> tchannon@black.demon.co.uk (Tim
Channon) writes:

>Sorry to disagree but to illustrate: I asked a  Polygram  engineer  during  a 
>live recording session how it was possible to record to apparently <1dB of 
>clip. He shrugged and just replied "It's ok if they play in tune" 8-)

And if not they use the master-tape instead...


>Sorry.  Fade a signal down to -80dB and listen. Just some added hiss and _no_ 
>noticable  distortion.  This  is  what dither is all about.  I have a digital 
>fader (re-dithered) which sounds ok when the music sound is at the same level 
>as the noise.  Switch the dither off and there is your  distortion  (or  more 
>precisely  quantisation noise which sounds a bit like crossover distortion to 
>me).

Adding HISS ? I was always told the very big advantage of digital recordings is
the absence of hiss. Just another way of restrecting the dynamic range on the
lower end.


>What is 80dBs above 1 watt per channel?

A lot, but what is 40dB's above 1 watt?


Greetings
           MARTIN
Newsgroups: sci.electronics
From: chuck@HQ.Ileaf.COM (Chuck Cullen x4423)
Subject: re: Active Noise Reduction
Reply-To: chuck@HQ.Ileaf.COM (Chuck Cullen x4423)
Organization: Interleaf, Inc.
Distribution: usa
Date: Wed, 12 Aug 92 16:38:52 GMT

>> Can anyone give me some pointers to info on or companies involved in
>> active noise cancelation using a mirror of the original noise?

From: cab@col.hp.com (Chris Best)
> David Clark headphones, which some people consider the top of the line,
> come in (I think) several active models.

The company who first introduced noise cancelation headphones is
Bose, Natick, Mass.
Bose had a stop ship but they are now shipping again.
You have to order them direct from Bose (508) 579-7330.

Dave Clark headphones in general are considered to be the best by some people
but I was not aware that their active noise cancellation headphones
are rated higher than Bose.
This would be a good question to post to rec.flying.
Maybe somebody who just came back from Oshkosh has some news.

Chuck Cullen
chuck@hq.ileaf.com
(617) 290-0710
-- 

Chuck Cullen
Interleaf Inc., Prospect Place, 9 Hillside Ave., Waltham MA   02154
chuck@stowe.HQ.Ileaf.COM
From: brianr@tekig1.PEN.TEK.COM (Brian E Rhodefer)
Newsgroups: sci.electronics
Subject: Re: 220V ac -> 6V DC @ 1mA, how?
Summary: Charge pump
Date: 18 Aug 92 02:16:49 GMT
Reply-To: brianr@tekig1.pen.tek.com
Followup-To: poster
Organization: Tektronix, Inc., Beaverton,  OR.

In article <1992Aug15.082131.29146@discus.technion.ac.il> s2859479@techst02.technion.ac.il (Yaron Keren) writes:
>I need to supply 5-8V DC at current of 0.7mA avg, 2mA max from the line
>(220V here) voltage. Since the current is very low, I thought to use a
>diode-resistor-zener+capacitor as a power supply instead of a tranformer.
>What are the disadventages, dangers, etc. inbvolved?
>Is there other simple way to do this?
>
>Please email and I'll summarize if there are enough responses.
>
>Yaron
>-- 
>Yaron Keren                                 s2859479@techst02.technion.ac.il


Assuming that you can stand to have whatever you're powering directly
connected to one side of the powerline, you could use a line-clocked
charge pump circuit:

At double your load's maximum current of 2mA, it would consume 4 / 60
milliCoulombs of charge every line cycle (I'm assuming the US mains
frequency of 60Hz here).  Moving that amount of charge by changing
the voltage on a coupling cap by 220 * SQRT(8), or 622 V would require
a capacitor no larger than about 0.1uF.

Your load-voltage variation of 3V is roughly 200X smaller this peak-to-peak
line voltage, so you'd need an output filter cap of at least 20uF.

So, you could try this circuit:

                    D2
 O-------||------*-->|-*------->
         C1      |     |+        8V, 2mA out
LINE            ---   --- C2
 IN           D1 ^    ---
                 |     |
 O--*FFF*--------*-----*------->
     Fuse

C1 -   0.1uF, 400V (Minimum) non-electrolytic

C2 -   100 to 200uF, 16V electrolytic

D1 -   8.7V (or so) Zener Diode.  It's important that this be a single-
       junction part, which will conduct in the "forward" direction,
       as well as in the `breakdown' direction.  If not, reverse-parallel
       it with a small-signal silicon diode.

D2 -   General purpose small-signal silicon diode. It'll only see 10V reverse.


Brian Rhodefer
From: taravade@elephant.ecn.purdue.edu (Kunal N Taravade)
Newsgroups: sci.electronics
Subject: Re: Beginners Question: RAS, CAS, and Refresh?
Date: 18 Aug 92 15:11:46 GMT
Organization: Purdue University Engineering Computer Network

etxansk@garbo.ericsson.se writes:


> I've been looking at chip descriptions for some common
>memory circuits. 

> There are pins on them named RAS, CAS, and Refresh. I know
>it's basic knowledge, but I'm not sure where to find good
>documentation on this.

> The RAS and CAS signals are probably input signals to the
>chip used during addressing. I've assumed that they're used
>to tell the chip whether it's the most or least significant
>part of the address vector that's currently on the address
>bus. If I'm right about this, how come there are _two_
>addressing control signals?

> For the Refresh signal: I can't recall if this one really
>is a pin on the chip or if it's some event that's done with
>other signals. I've heard that certain types of chips need
>this signal in order to work properly. What is the CPU (or
>the main clock, or the addressing logic) supposed to do to
>give the memory chips the refresh?
> 
> Anders Skelander
>

RAS = Row address strobe/select
CAS = Column address strobe/select

 These are used for refreshing, as you pointed out.
Because of the way in which the memory ICs are structured,
ie Row X Column, one of these two pins gets a low/high
signal that strobes all the rows(columns) while all the
columns(rows) in that particular row/column get refreshed.
This is repeated peroidically. The refresh signal usually 
disengages the read/write buffers and the chip goes into the 
refresh mode when   each location is refreshed as described 
above, simply by selecting the corresponding cell.


-Kunal
taravade@ec.ecn.purdue.edu 
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Wed, 12 Aug 1992 18:24:13 GMT
Subject: Re: How to dispose of NiCads?
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: sci.electronics

> :Intentionally discharging nicads to avoid "memory" is a waste of both time
> :and cells.
> :
> 
> Discharging is recomended by manufacturers of cordless phones and
> such.. are they just blowing smoke?

This question also came up in some e-mail I received - here's my reply:


> 
> You seem to know about this...
> 
> why exactly do manufacturers of
> nicad batteries and manufacturers
> of rechargeable devices such as
> Norelco Shavers, Remington, etc..
> tell you in their manuals to run
> the batteries down before re-chargeing?
> lance
> 

Two reasons - one is possibly valid, the other isn't.  The latter first:

The folks writing owner's manuals for consumer electronics aren't
necessarily battery experts; the NiCd "memory" myth has been pretty well
established, and if the manual writer even bothers to ask the engineer about
it, they're liable to hear, "Oh, yeah - they've got some sort of memory
problem.  Better tell 'em to run 'em down."  No one complains, as the unit
still works as advertised, even though the run-down is unnecessary and 
might even shorten the battery life by a few cycles (esp. if we *are*
talking about a battery and not a cell - deep discharge of a NiCd *battery*
runs the risk of reverse-charging those cells which discharge earlier than
the others, and so damaging them).

The slightly more valid reason is the way most folks use these appliances.
If not told otherwise, people simply leave their appliances connected to the
charger when not in use.  While NiCds *can* be trickle-charged, there may be
a slight problem with overcharge (and the resulting voltage depression) if
this is done; it's unlikely, but it could happen.

Also, don't assume that all of these appliances use NiCds; gel-cell lead-acids
are also very common in consumer gear, esp. when a heavy load is expected
(motorized equip. such as shavers, for example), and are somewhat better
suited to continuous trickle-charge.

Bob M.

Newsgroups: sci.electronics
From: ssomaroo@unpcs1.cs.unp.ac.za (Shyamal Somaroo)
Subject: Joysticks - IBM
Summary: Can anyone help me covert Atari joystick to IBM compat.?
Keywords: IBM
Organization: Univ. Natal, Durban, S. Africa
Date: Wed, 19 Aug 1992 20:28:36 GMT

Can anyone help me convert my Atari joystick D-type so that I
may be able to use it with my IBM compatible computer.

I already have a games port installed on my computer.

Send any ideas to :

    somaroo@unpsun1.cc.unp.ac.za

or ssomaroo@unpcs1.cs.unp.ac.za

Advance Thanx
Newsgroups: sci.electronics
From: jon_sree@world.std.com (Jon Sreekanth)
Subject: Re: Senate bill 1706 bans consultants?
Organization: The World
Distribution: usa
Date: Thu, 13 Aug 1992 01:50:09 GMT

In article <1992Aug12.160535.12945@ole.cdac.com> ray@ole.cdac.com (Ray Berry) writes:


	   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?

You could try asking in misc.jobs.contract

/ Jon Sreekanth

Assabet Valley Microsystems, Inc.           |  Fax and PC products
5 Walden St #3, Cambridge, MA 02140         |  (617) 876-8019
jon_sree@world.std.com                      |
Newsgroups: sci.electronics
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: Caller ID charges???
Summary: use a PC (callerID to RS232 interface)
Organization: Jeff's house of computer pieces
Date: Wed, 12 Aug 1992 20:09:03 GMT

>Has anyone come out with a caller id device which can be programmed
>to check a user supplied list of numbers and give the name, and
>block calls from specified numbers? That might convince me to get
>caller id. The call blocking would be unnecessary since I could always
>program in "Don't answer" for blocked numbers. I pick up some calls
>immediately rather than let my answering machine screen calls as I
>usually do now.

There are several modems and stand alone circuits that convert caller-id
to RS232.  Motorola and Sierra make the chips.

I have the International Micropower kit.  $50 for the board and the
MS-DOS software that only logs the phone number (no lookup).

ICON makes a board with software that does lookup, but it's over $300.

This has been discussed in comp.dcom.telecom and can be found in their
archives.  I have not yet written nor found public domain software
to do the phone number to name lookup.

There are certain advantages to having the rejection done by the
telephone company's switch.
'call block' doesn't even ring your phone.  The blocked caller gets a
message and is not charged for the call.  But you're limited to a list
of 6-10 numbers to block.

On premesis equipment can detect that you want to dodge the call.
Okay - what do you do?  Have the computer pick up the phone and
hang up right away?  It can take 20 seconds for the phone line to reset.
If the person calls you repeatedly, they can essentially deny you
dial tone and all incoming calls.
You can't get caller-id for calls that are on call-waiting, so the
annoying person can interrupt calls in progress if you have call waiting.
Call block should block the calls under all circumstances.

Until SS7 (the switching protocol that enables caller id) is implemented
between local regions, all out of area calls just display 'O'
for out of area.
Caller-id, call trace, return call are useless in such cases.

- Jeffrey Jonas
jeffj@synsys.uucp
synsys!jeffj@uunet.uu.net
-- 
-- 
Jeffrey Jonas

jeffj@synsys.uucp
Newsgroups: sci.electronics