HDTenEightyP/NetNews huggingface dataset:
From: schaerer@isi.ethz.ch (Thomas Schaerer)
Subject: Re: 0-38mV ==> 4-20mA Conversion
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: TIN [version 1.1 PL6]
Date: Thu, 19 Nov 1992 07:10:16 GMT

===============================================================================
Hello Jeff and all others,

Here is a low-cost-solution to convert 0...38mV to 4mA...20mA.  All  you 
need is a quad-opamp and a little bit of passive elements.


Build an inverting amplifier:

     >--------R1--|---R2----| <---- 0V ... 1.6V
                  |         |
 from Source      |---|- \  |
 0mV ... 38mV         |op1--|------R3---|---R4----|
                  |---|+ /              |         | 
                  |    Gain =           |---|- \  |      to current-
                  |    - 42.11              |op2--|----> voltage conv.
                 GND                    |---|+ /         0.4V ... 2V
                                        |                      |
                      U-offset = 0.2V >--    Gain = -1         |
     op3/op4:                                                  |
     --------                                                  |
     Here you must take one of the many voltage-current-       |
     converters. The decition of the kind of the circuit       |
     is given by precision and temperatur-coefficient.   <-----
     You will need one ore two opamps. Therefore for the
     whole circuit you need a quad-opamp.

If  the sourceimpedance is high you must set a high resistance  for  R1. 
The offsetvoltage U-off can deviate because of the inherent offsetvolta-
ge  of the first opamp op1.  You can comprise both function of  op1  and 
op2 to one opamp. But this is not recommendable because the outputvolta-
ge  of  this opamp influences the setting of the  offsetvoltage  if  you 
make it additional to the gain-resistance-network.  Then the  inverting-
input  is  not the "flying" ground in case of  the  noninverting  ampli-
fication!!!!

I hope I can help you something.
Greeting from  Thomas              schaerer@isi.ethz.ch
===============================================================================


Newsgroups: sci.electronics
From: tron@ux1.cso.uiuc.edu (Tron R.)
Subject: Voltage regulator
Organization: University of Illinois at Urbana
Date: Sun, 22 Nov 1992 08:39:53 GMT

I have posted a note earlier about converting a 9V dc source to 12V dc. It
turns out that I need to go from 9v to a stable output in the 7.5v to 8v
range. I am thinking about using using a voltage regulator ic. Does anyone
know of any Volt Reg. that will handle such a small input/output
differential?

Or is using a volt. reg. a bad idea for what I'm trying to do?

Thanks in advance.
Tron

P.S. I want to thank all the people that responded to my first posting. It
means a lot to a beginner like me.
From: ballen@convex.csd.uwm.edu (Bruce Allen)
Newsgroups: sci.electronics
Subject: How does a clamp-on ammeter work?
Date: 18 Nov 1992 05:30:04 GMT
Organization: Computing Services Division, University of Wisconsin - Milwaukee
NNTP-Posting-Host: 129.89.7.30

The title says it all:
"How does a clamp-on ammeter work?"
I'm thinking about one of the gadgets used to measure the 
current in an automobile charging circuit, for instance.
It has a pair of thick "jaws" that encircle the lead in 
question, and a meter that reads out the current passing 
through the encircled region, without intrusively breaking
or touching the wire.  Does it sense the B field?  If so, how?
	Thanks,
		B. Allen

Please reply to ballen@dirac.phys.uwm.edu

Newsgroups: sci.electronics
From: tmkk@uiuc.edu (Khan)
Subject: Re: Help! Converting 2400 to 9600 baud.
Organization: University of Illinois at Urbana
Date: Wed, 18 Nov 1992 13:52:34 GMT


In article <1992Nov17.174405.44889@kuhub.cc.ukans.edu> 2hujpapaw@kuhub.cc.ukans.edu writes:
>
>Has anyone ever had any luck (or ever tried for that matter) converting
>a 2400 baud modem to 9600 baud?  I have heard that it can be done fairly
>easily by replacing a few key IC's.  I will try to get the text file to
>do it if anyone is interested.

Don't bother. That text file is complete BS. There's no easy way to do
what you want; just save your money and get one of the new ultra-cheap
V.32 modems on the market now.
From: ivar@unixg.ubc.ca (ivar jonsson)
Newsgroups: sci.electronics
Subject: Heat sink
Date: 16 Nov 1992 18:29:10 GMT
Organization: UBC Pulp & Paper Centre
NNTP-Posting-Host: poplar.ppc.ubc.ca
Summary: Request for Modelling S/W
Keywords: Modelling

I am looking for S/W packages that are capable to model and simulate
a HEAT SINK .  My objective is to optimize the haet removal from a high
powered circuit.  Any suggestions will be helpfull.

Best regards,

Ivar Jonsson
K
From: re_sims@vax.muskingum.edu
Newsgroups: sci.electronics
Subject: Bearcat frequency mods????
Date: 23 Nov 92 13:49:49 GMT
Organization: Muskingum College



Help,

   does anyone know of any mods to get more
frequencies on a Bearcat 300?

Thanks in advance

Jim Sims sr. N4JDP
re_sims@vax.muskingum.edu
From: rrw@sunset (Bob Wier)
Newsgroups: sci.electronics
Subject: Re: 68HC11 Floating Point Routines
Date: 21 Nov 92 07:50:14 GMT
Originator: rrw@sunset.cse.nau.edu

From article <1992Nov17.135342.5959@rdg.dec.com>, by franzoni@sixter.var.dec.com (Mauro Franzoni):
> In article <1992Nov9.214242.11948@nntp.hut.fi>, sakaria@vipunen.hut.fi (Sakari
> Aaltonen) writes:
> |> The source code is available for ftp, too. Somewhere there's an .edu
> |> site that has rather a lot of HC11 stuff. You guessed it: I can't remember
> |> the name of the site...
> 
> try calvin.stanford.edu or elden.cse.nau.edu

  Please note that the HC11 mailing list/archives 
  formerly on elden.cse.nau.edu have been moved to
  red.cs.tcu.edu (138.237.7.8) due to the withdrawal of support for
  this service by the great state of Arizona (are you listening in
  Phoenix, Motorola?).

  Many thanks for Texas Christian U. in Texas for providing the disk
  space and cpu cycles to continue this...

- Bob Wier

  ---------- insert favorite standard disclaimers here ----------
                   College of Engineering
      Northern Arizona University, Flagstaff Arizona
  Internet: rrw@naucse.cse.nau.edu | WB5KXH | fax:602 523 2300
Newsgroups: sci.electronics
From: "Gary A. Woodward" <p00140@psilink.com>
Subject: integrated circut microlithography
Organization: Performance Systems Int'l
Date: Mon, 23 Nov 1992 14:44:07 GMT
X-Mailer: PSILink (3.2)

I have searched the libraries here in DC and found only information on 
printing lithography.  I need some info on the lith such as that used in 
making IC chips.  Also some info on the chips (silicone) themselves.

thanks in advance.

GW
Newsgroups: sci.electronics
From: dherity@cs.tcd.ie (Herity D.)
Subject: How is this (SDLC?) CRC computed ?
Keywords: SDLC, CRC, MNP
Organization: Computer Science, Trinity College Dublin
Date: Thu, 19 Nov 1992 17:46:55 GMT

I'm doing an SDLC implementation in software (processing every bit) and
am stumped by the CRC calculation.
I receive a packet 03h,05h,08h,17h,31h,94h, the last two bytes of which are
the CRC. This is in MNP level 5. I've read several versions of how the
SDLC CRC is computed, but I can't reproduce it. I've tried CRC-CCITT,
CRC-16, LSB first and MSB first, initialising to 0s and 1s, but there's
something missing.

Suggestions, anyone ?

-- 
================================================================================
| Dominic Herity,  dherity@.cs.tcd.ie,                      | Something clever |
| Computer Science Dept, Trinity College, Dublin 2, Ireland.| coming soon to a |
| Tel : +353-1-6772941 ext 1720 Fax : +353-1-6772204        |signature near you|
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Newsgroups: sci.electronics
Subject: Re: How to build a noise reducer?
Date: 18 Nov 92 16:13:32 GMT
Article-I.D.: athena.1992Nov18.161332.532
Organization: AI Programs, University of Georgia, Athens

In article <zhenya.722059559@ultima> zhenya@socs.uts.edu.au ( The Firefox.) writes:
>Does anyone have any ideas about the best way to build a device that takes
>an input from an external microphone, shifts the signal 180 degrees out
>of phase, and then re-emits it with little loss of resolution of the
>waveform in the process?

To shift a sine wave 180 degrees = to turn it upside down.

Why not just reverse the leads on the speaker?




-- 
:-  Michael A. Covington     internet mcovingt@uga.cc.uga.edu 
:-  Artificial Intelligence Programs       phone 706 542-0358
:-  The University of Georgia                fax 706 542-0349
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI
Newsgroups: sci.electronics
From: grier@bnr.ca (Brian Grier)
Subject: Re: Dipol Simulation wanted!
Organization: Bell Northern Research
Date: Sat, 21 Nov 1992 19:16:46 GMT

I would recommend MINEC. It can handle just about any antenna,
from a 1/4 wave to a 12 element yagi. I do not know exactly 
where to find a PD version, I recommend asking over in rec.ham-radio.

I have sources for the ATARI STe/TT but you probably want them for 
some other, less user friendly system, like a PC or a MAC. :^)

Brian, WS1S
Bell Northern Research
Research Triangle Park, NC
bjgrier@bnr.ca
From: sm@cel.co.uk (salim mehta)
Newsgroups: sci.electronics
Subject: Japanese AC line voltage
Date: 19 Nov 92 14:46:48 GMT
Organization: Crosfield Electronics Ltd.

I wonder if anyone can help me to find the AC line (mains) voltage and
frequency ranges that equipment is required to operate over in Japan.

I am familiar with:

1)  87 - 132VAC   47 - 63Hz for USA

2) 175 - 264VAC   47 - 63Hz for Europe

The general consensus is that the AC line in Japan is subject to much more
fluctuation than we are used to in the UK. I believe it is even worse than
the US!

What are the *regulatory standards* ?

I'd appreciate any help, thanks.

--
-------------------------------------------------------------------------
Salim Mehta                             Phone :  +44 442 230000  x3450
Crosfield Electronics Ltd               Fax   :  +44 442 232301
Hemel Hempstead  HERTS HP2 7RH  UK      Email :  sm@crosfield.co.uk
-------------------------------------------------------------------------
     Alt email :  sm@cel.uucp     ...!{mcsun,uknet,uunet}!cel!sm
-------------------------------------------------------------------------
From: dcg5662@hertz.njit.edu (Dave Grabowski (KxiK))
Newsgroups: sci.electronics
Subject: Re: Request for information about the 6502 microprocessor
Date: 17 Nov 92 02:53:45 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.

In article <1992Nov16.133125.461@cimage.com> tgamble@cimage.com (Rick Campbell /10000) writes:
>Mark James Collier (mjcol@dcs.warwick.ac.uk) wrote:
>: Does anybody know how I can get as much information as exists about the
>: 6502 microprocessor? For my third year project I am emulating the 6502 at the
>: cycle level, ie via its internal registers. Thus I need to know information
>: not normally included in programming texts. Can anybody recommend a book
>: (eg what is Rodney Zak's 'Programming the 6502' like?) or provide an e-mail
>: address for RockWell (or the designers of the chip, if not them)?
>: 
>
>A few years back I worked with the Commodore VIC-20. This computer contains a
>6502, and the information included in some of the many programming books was
>pretty detailed. The computer also came with a complete schematic, including
>all the support chips. I have seen these computers in the paper for as little
>as $20. 
>
>
>-- 
> Rick Campbell  
> Internet: gamble@cimage.com
>     -or-: emunix.emich.edu!rc3502

  The Commodore 64 was very similar, except that it was besed in the
6510. The 6510 was based on the same instruction set, but had minor
differences (which I don't remember). The _Programmer's_Reference_Guide_
published my Commodore had about half of its pages dedicated to ML, the
opcodes, clock cycles, chip data, pinouts, and a big (suitable for
framing) schematic in the back.

-Dave
-- 
-----------------------------------------------------------------------------
Kappa Xi Kappa - Over & Above!                         dcg5662@hertz.njit.edu
9 Sussex Ave., Newark, NJ (car theft capital USA)   70721.2222@compuserve.com
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: How to build noise reducer?
Date: Thu, 19 Nov 92 02:24:26 CST
Organization: The Inquiring Mind BBS  1 204 488-1607

zhenya@socs.uts.edu.au ( The Firefox.) writes:

> Does anyone have any ideas about the best way to build a device that takes
> an input from an external microphone, shifts the signal 180 degrees out
> of phase, and then re-emits it with little loss of resolution of the
> waveform in the process?
> 
> It would be great if it could also work from frequencies of about 20Hz up...
> 
> Maybe there is a mail-order kit for something similar that someone know of?
> 
> Thanks in advance...
> Zhenya.
> 
> --
> Ring Bad News BBS - +61 2 587-8441
> -----------------------------------------------------------------------------
> | _    /| |`I am not	  |(Enter your next mistake?)% ping elvis |	  /// |
> | \'o.0'  |  the Messiah!'| elvis is alive			  |	 ///  |

HOW ABOUT AN AUDIO TRANSFORMER matched to the impedance of the mike.
Then just invert the output (ie reverse output leads). This would work 
for high output mikes. But better to do this a line output levels, since 
low impedance mikes are not high level output.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
Newsgroups: sci.electronics
From: truben@vipunen.hut.fi (Trygve Nyman)
Subject: VGA feature connector pinout
Organization: Helsinki University of Technology, Finland
Date: 16 Nov 92 15:34:19 GMT

Anybody got the pinout of the feature connector
found on most VGA-cards? Complete specifications
and points to litterature would be even better...

Thanks,
truben


-- 
Trygve Nyman          #   Trygve.Nyman@hut.fi    *   + 358 0 468 2206
JMT 1A56              #   truben@vipu.hut.fi     *     
02150 Esbo, FINLAND   #   ...                    *     Hej hopp!
Newsgroups: sci.electronics
From: govindg@ucunix.san.uc.edu (Girish Govind)
Subject: Re: How to build a noise reducer?
Organization: University of Cincinnati
Date: Wed, 18 Nov 1992 17:55:53 GMT

I am assuming that all of you are talking about doing what is called active
noise control. This is not so easy as switching the leads of the speaker or
microphone. Because

1) The speaker has to be placed very very close to the microphone
2) the 180 degrees delayed waveform called "anti-noise" shows up in the
   reference signal. Because of 1)
3) The amplitude needs to be adjusted and limited.
4) The acoustics of the room will keep changing and that means one has to have
   an adaptive system.
5) The noise will only be cancelled at the error microphone and may add to the
   existing noise at other points in the room.

If you have some of the last few issues (October) of EE Times you may 
read about the acoustic noise control muffler for cars that is being put 
out by Walker mufflers. It is supposed to provide as good cancellation as 
existing passive mufflers and also provide better mpg from your car as 
the fuel burns cleaner when there is no back-pressure induced by the 
passive muffler.

Also, acoustic noise control was used by headphones designed by Bose which
were used in the Voyager flight couple of years ago.

Some active companies in this area are Noise Cancellation Technologies and
Active Noise & Vibration Technology.

There are a whole bunch of papers available on this.... I have a list of some
of the good ones. If someone is interested, email me.

-- Girish Govind
   govindg@ucunix.san.uc.edu




Newsgroups: sci.electronics
From: schuster@panix.com (Michael Schuster)
Subject: Re: Nickel Metal Hydride batteries
Date: Sun, 22 Nov 1992 03:22:17 GMT
Organization: PANIX Public Access Unix & Internet, NYC

In article <cerulean.722222768@access.digex.com> cerulean@access.digex.com (Bill Christens-Barry) writes:
>I'd like to get some C size nickel metal hydride batteries for an r/c car
>and some AA size batteries for other purposes.  Can anyone suggest where
>I can get these and what they should cost?

Someone posted here that Real Goods (Ukiah, Ca; 800-762-7325)
sells 1100 mAH AA's for $8/cell. 

While the NiMH pack in my Toshiba laptop is great, I've had absolutely
no luck in getting anywhere near the rated capacity out of a bunch
of Gold Peak NiMH AA's I bought at the Trenton Computer Festival this year.

-- 
_______________________________Mike Schuster________________________________
NY Pub. Access UNIX/Internet: schuster@panix.com | 70346.1745@CompuServe.COM
The Portal (R) System: schuster@shell.portal.com | MCI Mail,GEnie: MSCHUSTER
From: cmh@eng.cam.ac.uk (C.M. Hicks)
Newsgroups: sci.electronics
Subject: Re: BROKEN TUBE AMP
Date: 16 Nov 92 12:31:15 GMT
Organization: cam.eng

sehari@iastate.edu (Babak Sehari) writes:

>In <kkv1+xl@rpi.edu> nasiom@vccnw10.its.rpi.edu (Milton Peter Nasiopoulos) writes:

>Q. How to check specker impedance.
>A. Use a signal generator, to generate a 1KHz signal put the speaker and
>   a one ohm resistance in series, and connect the speaker-resistance
>   combinations to the signal generator. Measure, the voltage across the
>   speacker and the one ohm resistor. Now you can calculate the speaker's
>   resistance at 1KHz.  Also check the DC resistance of the speaker with
>   ohm-metar.  Your future speackers should have the same impedances.
>Q. What could have gone wrong?
>A. The output transformer that connects the speakers to Amp. might have
>   shorted itself.  If so, it should be changed.  Look at the resistors
>   see if you can find burning sign on those.  See if the Amp burns the
>   fuse without speakers?  Also, tube Amp are not supposed to run with
>   Sq. waves or very high frequencies.

>Good luck, let me know if you had more problems.

>                With highest regards,
>                     Babak   Sehari.

If the amp is old, it may also be worth changing all the electrolytic 
capacitors as a matter of course, since old electrolytics often go leaky.

Christopher Hicks (cmh@uk.ac.cam.eng)
Newsgroups: sci.electronics
From: mcovingt@aisun3.ai.uga.edu (Michael Covington)
Subject: Re: Japanese AC line voltage
Organization: AI Programs, University of Georgia, Athens
Date: Fri, 20 Nov 1992 03:37:09 GMT

In article <SM.92Nov19144648@suns2.cel.co.uk> sm@cel.co.uk (salim mehta) writes:
>I wonder if anyone can help me to find the AC line (mains) voltage and
>frequency ranges that equipment is required to operate over in Japan.
>
>I am familiar with:
>1)  87 - 132VAC   47 - 63Hz for USA

Huh?  US power is 110 to 125 volts, 60.00 Hz.  
I think the numbers you quote are for a _combination_ of US and Japanese
power; Japanese is 100 V at 50 Hz if memory serves me right.

(Hang on; why rely on memory?  The World Radio-TV Handbook says
that Japanese power is 50 or 60 Hz depending on where you are; it
doesn't give the voltage.)
-- 
:-  Michael A. Covington     internet mcovingt@uga.cc.uga.edu 
:-  Artificial Intelligence Programs       phone 706 542-0358
:-  The University of Georgia                fax 706 542-0349
:-  Athens, Georgia 30602-7415 U.S.A.     amateur radio N4TMI
From: danodom@matt.ksu.ksu.edu (Dan Odom)
Newsgroups: sci.electronics
Subject: Re: Big Brother Radio Shack
Date: 16 Nov 1992 18:48:04 -0600
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu

ac94691@dunix.drake.edu (The Dark Kitty) writes:

>Oh yeah, did this click real well in my mind.  I don't know how many
>times I've gone into the local Radio Rip Off Store and asked for a
>certain size of capacitor/resistor that hasn't been restocked only to
>be told "capacitors?  I'm not sure I know what those are.  I don't think
>we carry those."  Aiiiiiigggghhhh!!!  I also don't know how many times
>I've been browsing and overheard a salesman tell another customer that
>RS doesn't carry an item that I happen to be looking right at!

Yes, or when they tell you "If you want to get a transformer for your kid,
try Toys-R-Us.  We don't do that stuff.".  Or "What's an IC again?".
Or "RJ14?  Is that the new computer game?".  Or (etc. etc. ad nauseam (sp?))
I go mail order whenever possible.
-- 
Dan Odom
Kansas State University
danodom@matt.ksu.ksu.edu
Member of the League for Programming Freedom; mail lpf@uunet.uu.net
From: John.Seboldt@f31.n282.z1.tdkt.kksys.com (John Seboldt)
Sender: FredGate@tdkt.kksys.com
Newsgroups: sci.electronics
Subject: making mono from stereo
Date: Sun, 15 Nov 1992 14:59:04 -0600

On 11-10-92, PETRY,DIRK./PPE wrote to All:

>------------------------------------
How can the two speaker outputs of a stereo hifi set be combined to one?

Since the human ear is only able to locate sources of sound if they
emit medium or high frequencies, it is not sensible to have two bass
speakers in a hifi set. A cheaper but as good solution would be to
have two medium and high frequency speakers, and only one bass speaker
connected to both output channels.
Surprisingly there no solution to this available, not even at  
specialized hifi electronics shops.


>------------------------------------

Nonsense.  Find the right shop or mail order house.  Wish I could be more 
specific, but I have seen several subwoofer systems that do exactly as you 
propose.  Some have built-in amplifiers that take input from your 
speaker-level lines (without loading them down) -- others do it passively 
(less desirable) -- and there are some complete systems with three units 
-- 1 subwoofer and 2 tiny satellite units with midrange and treble drivers 
in each one.




 * Freddie 1.2 * Unix soit qui mal y pense!

 * Origin: Dark Knight's Table (1:282/31)
Newsgroups: sci.electronics,rec.audio.car,alt.locksmithing
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Gemini 4002/4003 car alarm
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Sat, 21 Nov 1992 09:15:45 GMT

hb@imsor.dth.dk (Henrik Bechmann) writes:
: I have one of those fitted in my car, and the users manual states that
: it is possible to switch between voltage sensing mode and no voltage
: sensing mode by setting a switch. I don't want it to be voltage
: sensing, but the alarm reacts on voltage changes in both modes :-( 
: 
: Does anybody out there have any suggestions to solve the problem
: (without a separate battery for the alarm), or does anybody have acces
: to a Service Manual or an electronics diagram of the thing?
: 
: Any help will be very much apreciated.

It sounds like you misunderstand what is being talked about. Voltage
sensing is when the alarm detects a change from zero voltage to some
positive/negative voltage level. No-voltage sensing is when the alarm
senses a change from a positive/negative voltage to zero voltage. In
both modes, the alarm is reacting to a voltage change.

Bill
Newsgroups: sci.electronics
From: joe@netcom.com (Joseph Jesson)
Subject: Re: SCA Reciever Design
Organization: Netcom - Online Communication Services (408 241-9760 guest)
Date: Fri, 20 Nov 1992 20:57:05 GMT

 SCA receivers require a quality bandpass filter on the front end.  Every
 receiver chip (XR2211 and CA3189) has excess main channel crosstalk
 to be commercial quality.  It works, just not noise-free...


 joe jesson

Newsgroups: sci.electronics