HDTenEightyP/NetNews huggingface dataset:
From: ggonzale@mtecv2.mty.itesm.mx (Gabriel Gonzalez)
Newsgroups: sci.electronics
Subject: Temp system 4 Delta Net?
Summary: System design for delta-net controller
Keywords: temperature, delta-net
Date: 15 Oct 92 23:46:03 GMT
Organization: I.T.E.S.M. Campus Monterrey

Hi there,
I need a design for a temperature transducer system for a Delta-Net
controller.
The requirements are:
	Transmitter:
			-10^C to 50^C
			resolution 0.1 ^C
			3 digit display with ^C & ^F (selectable)
	Receiver:
			converts current to frecuency
			pulses from 0 to 9 volts

	There must be a current loop between the rx & tx of 4mA to 20mA
(linear response). There are power supply voltages from -12v to 12v. The
frecuency of the receiver to the Delta Net must be from 740 Hz for -10^C
to 13 KHz for 50^C. A twisted pair telephone line will be used between
the receiver and the transmitter with a maximum resistance of 500 ohms.
The system must be as cheap as possible.

	Any help will be appreciated. This is a final project for an
electronic laboratory. Help me pass.

	Thank you.

	Calvin (Gabriel Gonzalez)
	internet:ggonzale@mtecv2.mty.itesm.mx
From: jfw@ksr.com (John F. Woods)
Newsgroups: sci.electronics
Subject: Re: Sam's Photofacts
Date: 9 Oct 92 15:06:54 EDT

vbreault@rinhp750.gmr.com (Val Breault) writes:
>In article <BvtAFx.HLo@ais.org> danr@ais.org (Daniel Romanchik) writes:
>   Path: rphroy!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!destroyer!ais.org!danr
>   Does anyone still publish Sam's Photofacts?
>   If so, who?  How can I contact them?
>   Thanks, Dan
>One of the better kept secrets:
>Your local Radio Shack can get them for you.

YOUR local Rat Shack may be able to get them for you, but MY local Rat Shack
took 5 weeks to finally decide that they couldn't get the one I wanted; they
said that SAMS didn't print that one any more.  However, SAMS (1-800-428-SAMS)
disagreed, and sent me the one I wanted in under a week.
From: jefff@cbnewse.cb.att.com (jeffrey.l.knopp)
Newsgroups: sci.electronics
Subject: 486 CPU Heatsink/fan Unit For Sale
Keywords: 486 cool
Date: 8 Oct 92 15:44:16 GMT
Article-I.D.: cbnewse.1992Oct8.154416.11725
Distribution: usa
Organization: AT&T



Thermalloy Heatsink Fan Unit for 486 CPUs, 

	-Ideal for 486SX, 486DX, or 486DX2 CPUs	ANY SPEED
	-Reduces Temperature of CPUs to cool finger touch
        -Includes Heatsink/Fan Unit, Mounting Hardware, Easy 
         Installation Instructions
        -Connects to +5V Supply (Optional PC Power Supply Connector
         Available. Connector is Y'd so you don't lose a PS plug)

These units are designed specifically for 486 CPUs.  They are not some 
cheap fan that installs in the PC.  This same unit without the mounting
hardware is listed at $49.95 in Oct. Computer Shopper (see ad for 
picture).
 
I have contacted several people who have purchased these units.  They
have been delighted with the results.  When you have big $$ invested
in a CPU, why risk premature failure from heat? (I know, the RISK is
debateable)  I have personally seen 486DX 50MHz CPUs experience
lockups.  After installing the fan heatsink, no more problems.  Also,
I'm TOLD INTEL does not warrantee 486DX 50 CPUs.

I am not sending COD anymore because it adds cost.  I am relying on
the honesty of my fellow man.

$31.00 INCLUDES SHIPPING
$33.00 with PC power supply connector installed

Jeff Knopp
jefff@ihlpl.att.com
708-979-1725
Newsgroups: sci.electronics,comp.sys.ibm.pc.hardware
From: sehari@iastate.edu (Babak Sehari)
Subject: Re: hardware solution for speaker volume ?? help!??
Originator: sehari@vincent1.iastate.edu
Organization: Iowa State University of Science and Technology, Ames, Iowa.
Date: Fri, 9 Oct 1992 18:50:02 GMT

In <1992Oct9.040641.24116@jupiter.sun.csd.unb.ca> q1hl@jupiter.sun.csd.unb.ca (Nameless CS Student) writes:

>In article <Bvu35G.5vC@gpu.utcs.utoronto.ca> darek@gpu.utcs.utoronto.ca (Darek Dabrowski) writes:
>>I need a simple way to lower the volume of the computer's speaker...
>>I need the hardware solution, and must be simple. (i am not a pro)
>>
>> the speakerconnector is 1--Data out
>>                         4-- +5V

>Simply connect the speaker in series with a variable resistor of
>maybe 10 or 20 ohms.  Speaker volume is a function of current, and
>the speaker output is constant voltage.  At you increase the
>resistance of the added potentiometer, the current flowing through
>the speaker will decrease, leading to lower volume.  At minimum
>setting (0 ohms), the speaker will be loudest.

That's one solution but might not really, decrease the sound level that
much.  This is due to the fact that sound is a log creature not a linear
creature.  So make sure to buy logorthmic variable resistor from 10 to 100
Ohm. Then discounect one speaker wire connect it to one side of the
variable resistor, connect the other side to the wire already connected to
speaker, and finally connect the middle head of the variable resistor to 
the other side of speaker which does not have any connection like this:

               _____
   From Computer   |
                   <            /
                   > <-----|  /
                   <       8||
                   |       8||
               ------------|  \
                                \
                       

                 With highest regards,
                      Babak   Sehari.
-- 
Newsgroups: sci.electronics
From: vreeburg@fys.ruu.nl (Jurriaan Vreeburg)
Subject: Re: 25 ohm coax cable
Organization: Physics Department, University of Utrecht, The Netherlands
Date: Tue, 13 Oct 1992 10:17:50 GMT

In <93M202YG25hl01@JUTS.ccc.amdahl.com> dhi00@ccc.amdahl.com (mofo ) writes:

>regarding the following figure:


>                50 ohm
>           =============
>25 ohm  //               \\   25 ohm
>========  A             B  ============
>        \\               //            |
>          ===============             ---
>              50 ohm                  | |
>                                      | | 25 ohm
>                                      | |
>                                      ---
>                                       |
>                                      GND


>i think this is what you have when you launch a wave down the
>coax:

>a signal of voltage v and current i travels down the first
>length of coax.  it encounters the 25 ohm 'T' splice and sends
>a signal of voltage v and current i/2 down each branch with
>no reflection.  

>if the two branchs are equal in length, the signals travel
>and meet at splice B.  this gets a little tricky.  a wave front
>traveling along the south branch would approach splice B and
>see an approx. 17 ohm impedance (50 and 25 in parallel).  the
>reflection generated from a 50 to 17 ohm mismatch is about 
>1/2 the incident wave so at the splice, the signal is reflected

No, the reflection coefficient at B isn't 1/2, if you assume that
the signal sees a 17 ohm impedance. In that case 50-17/(50+17) would
be reflected.

>back down the south branch with voltage 1/2 v.  as it happens,
>the other branch has provided a boost of 1/2 v as well at precisely
>the same time and therefore a signal of v is created at splice
>point B (works the same from either branch).


>that boost is because of the mismatch, i.e., half of the signal was
>reflected, half transmitted.  the reflected signal is exactly cancelled
>by the other branchs transmitted signal.  at splice B, your left with
>the newly created copy of the signal which is free to travel down
>the 25 ohm coax in its original form (+/- capacitive/inductive effects
>due to bad solder job.

>d

So far, I'm not convinced by any of the netters. I think I'm going to
set up an experiment, and try to find out what is will happen, but I don't
think I'll be able to explain the things I'm going to see on my oscilloscope.

-- 
Jurriaan Vreeburg                             email: vreeburg@fys.ruu.nl
Department of Physics and Astronomy           tel.:  (+31)-(0)30-534566
P.O. Box 80.000
3508 TA  Utrecht  Holland
Newsgroups: sci.electronics
From: sleat@kpc.com (Michael Sleator)
Subject: Re: variable speed/pitch cd decks modification?
Organization: Kubota Pacific Computer
Date: Thu, 15 Oct 1992 05:33:00 GMT

In article <06cM02bT263G01@JUTS.ccc.amdahl.com>, drp40@cd.amdahl.com (Doug Puchalski) writes:
|> . I am looking for a way to modify a cd player to be able to vary the
|> . pitch approx +/- 10%.   I am hoping for there to be a potentiometer in
|> . the unit that is used for factory adjustment to specs...
|> 
|> I asked this question on the net a year or two ago and someone said
|> that Denon had a player out there with a pitch control on it.  I never
|> saw one though.  Perhaps it was a "studio" type player?  I say that because
|> I doubt they would market such a player for normal home usage--there just
|> wouldn't be a demand for it.


I beg to differ.  I have a Denon DCD-860.  It has pitch control.  You can even
control the pitch via the IR remote unit.  I find this very useful when playing
an instrument along with a recording, particularly since folk/celtic/old-time
music isn't always recorded at standard pitch.  Having to retune my mandolin
for every track would be bad enough, but retuning a hammered dulcimer every
time is right out!

The DCD-760 is a less expensive model that also has this feature.  I bought
my DCD-860 a couple of years ago; I don't know what the current models are
like.  So, to the original poster, unless you're in it for the fun of mucking
about inside a CD player, why not just buy one of these models and save
yourself a lot of trouble?


Michael Sleator                 Voice:          408-748-6339
Kubota Pacific Computer         FAX:            408-748-6301
2630 Walsh Ave.                 internet:       sleat@kpc.com
Santa Clara, CA  95051          uucp:           ...!uunet!kpc!sleat
From: vnelson@ccu.umanitoba.ca (Gerald Vernon Nelson)
Newsgroups: sci.electronics
Subject: Re: Serial line booster
Date: 13 Oct 92 01:36:41 GMT
Organization: University of Manitoba, Winnipeg, Canada

In <1992Oct12.035524.1202@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:

>Interesting.  I have a similar problem where one of the machines is a
>Sparcstation whose outputs are +-5 volts rather than the usual +-12.
>The first thing I'd check is whether you're getting true RS-232 voltage
>out of both machines.  If not, add a booster at the source, not in the
>middle of a 50-foot cable.  Are you sure the problem isn't something
>else, such as crosstalk between wires?

RS-232 levels are 3 to 25 and -3 to -25 volts.  A machine using
+-5 should be able to communicate to a machine using +-12, without
modification.  As suggested, it is probably cross-talk.

Try a twisted pair cable.

Vern Nelson
From: jko@atl.scscom.com (Jonathan O'Neal)
Newsgroups: sci.electronics
Subject: Need "Phone line in use" circuit
Summary: see subject
Keywords: help need phone line in use circuit
Date: 11 Oct 92 17:33:57 GMT
Reply-To: jko@atl.scscom.com
Organization: SCS/Compute, Inc.


   Greetings, netland.  I expect this is a FAQ, but I haven't seen mention of
it lately.  I need to create a device to let me know if a phone line is in
use (we have modems, a fax, and voices competing for the same line; as you
know, modems and faxes don't take kindly to being interrupted).  I imagine
it's as simple as an LED attached to a voltage comparator circuit, but I'm
ignorant of the details of the phone system.  A schematic would be great;
even a detailed description would suffice (I'm hardware-competent).  E-mail
is fine, or post here if you like.

   Thanks in advance.

   Jonathan O'Neal
-- 
 Jonathan O'Neal      jko@atl.scscom.com     ...!uunet!emory!scscom!jko
 DataScape, Inc.      WD4DAR                 Any opinions expressed are all
 Atlanta, GA          (404) 518-8480         mine, not those of DataScape.
From: denny@hpscit.sc.hp.com (Trueman Denny)
Newsgroups: sci.electronics
Subject: Re: Large LED Reader Board info wanted!
Date: 16 Oct 92 21:17:45 GMT
Organization: Hewlett-Packard, Santa Clara, CA

Try a company from Japan called Stanley.  LED Displays of all types are their
specialty.  

Their Loa Angeles Sales Office:  800  LED-LCD1
                                 714  222-0777

                                 714  222-0555 (FAX)

                                 2660 Barranca Parkway
                                 Irvine, CA  92714
From: steuer@clam.rutgers.edu (robert Steuer)
Newsgroups: sci.electronics
Subject: Need Help with Op-Amps
Date: 7 Oct 92 17:47:20 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

I just finished an Electric Circuits Lab and one of the circuits
involved an op-amp where the op-amp had its two bipolar power supply
connections, and a signal generator was feeding a sine wave into the
non-inverting input of the op-amp.  Then, a direct connection was made
from the output to the inverting input and the gain was measured.  It
was found that there was no change in the gain.  Then, the same
circuit was used but instead of the piece of wire going from the
output to the inverting input a 27k resistor was used and the gain
remained the same although one would have thought it would
decrease.(At least I did anyway!)  Is this because there was no second
resistor that would normally have gone from the inverting input to
ground?  That is all I can come up with because the formula to
calculate gain is Afb=(Rf)/(R1) + 1 for closed loop gain.
Can anyone verify that my assumption is correct or not?
                                  Thanks, Rob
Newsgroups: sci.electronics
From: fff@microplex.com (Fred Fierling)
Subject: AC Power Sources (California Instruments)
Organization: Microplex Systems Ltd
Distribution: na
Date: Thu, 15 Oct 1992 19:49:34 GMT

Who besides California Instruments makes AC power sources?  I'm looking for
a piece of equipment that can simulate AC line power from all over the world.
Something that runs off of 110VAC and provides 0 - 270 VAC, 50 or 60 Hz,
100VA outputs.  (California Instrument makes such equipment but it seems
awfully expensive).
-- 
Fred Fierling    fff@microplex.com      Tel: 604 875-1461   Fax: 604 875-9029
Microplex Systems Ltd   265 East 1st Avenue   Vancouver, BC  V5T 1A7,  Canada
Newsgroups: sci.electronics
From: Bob.Clarke%bbs@actcnews.res.utc.com (Bob Clarke)
Date: Wed, 07 Oct 92 12:02:44 EDT
Organization: United Technologies Research Center
Subject: Re: No Clean Solder Flux
Distribution: world
X-Posting-Software: UnixBBS 1.02a S/N 190921

I guess I should be more exact.  It is our understanding that no clean
flux leaves a film.  It is said this film is inert.  Has anyone
verified this?  In the aerospace business we are verrrry conservative
(like extreme).  Our products are very expensive and have to have high
reliability, next time you fly one of our products will be with you. 
We have to prove to our customer's that a change over to no clean flux
will have no effect on reliability.  So, any aerospace companys using
no clean flux?  Have you done any testing?  Would you be interested in a
dialog?
--
Bob Clarke, user of the UnixBBS System @ actcnews.res.utc.com
E-Mail: Bob.Clarke%bbs@actcnews.res.utc.com
========================================================================
   United Technologies Corporation
   Opinions expressed do not necessarily represent UTC.
From: pauls@trsvax.tandy.com
Date: 12 Oct 92 17:11 CDT
Newsgroups: sci.electronics
Subject: Re: Small audio device
Message-ID: <288200021@trsvax>
Nf-ID: #R:<4XkcsB2w165w@sys6626.bison.mb.c:-34:trsvax:288200021:000:210
Nf-From: trsvax.tandy.com!pauls    Oct 12 17:11:00 1992


Our new wireless mic, catalog #32-1224 @139 works great. It as has
companding noise reduction and low noise NE5532 op amps throughout.

Disclaimer >>>> NOT AN AD. JUST HELPING. DONT CARE IF YOU NEVER BUY ONE!


Newsgroups: sci.electronics,rec.radio.cb
From: ornitz@kodak.kodak.com (Barry Ornitz)
Subject: Re: Radio Shack pagers
Followup-To: sci.electronics
Summary: R/C licensing
Organization: Eastman Chemicals Company
Distribution: usa
Date: Wed, 7 Oct 92 21:00:55 GMT

In article <laird.718485972@stable.ecn.purdue.edu> laird@stable.ecn.purdue.edu 
(Kyler Laird) writes:
>RS here is selling the pager base and one mobile for $99.  I noticed
>that this is a digital system and that the schematics are included.
>Has anyone tried hacking this?  It operates near 27MHz with a reported
>range of >2 mi.
>I'd like to use the digital in and out for a alphanumeric pager.

This unit is licensed as a radio control system.  The transmitter must be
type accepted and hacking on it voids this.  R/C systems may not be used to
transmit any message other than for the operation of devices at remote
locations.  In this case, the receiver turns on a tone generator.  No voice,
telegraphy, etc. may be used.  FCC Part 95.212 also prohibits transmitting
data:
       "Tone or other signal encoding, however, is not considered to be data
	when only used either for the purpose of identifying the specific
	device among multiple devices that the operator intends to turn on/off,
	or the specific sensor among multiple sensors intended to turn on/off
	indicating device for the operator."

Your alphanumeric paging application is definitely illegal under R/C rules.
It would also be illegal under CB rules since the only no-voice transmission
permitted under CB rules is limited to selective calling of tone-operated
squelch tones to establish of continue voice communications.

					Barry
 -----------------
|  ___  ________  |       Dr. Barry L. Ornitz          WA4VZQ
| |  / /        | |       Eastman Kodak Company
| | / /         | |       Eastman Chemical Company Research Laboratories
| |< < K O D A K| |       Process Instrumentation Research Laboratory
| | \ \         | |       P. O. Box 1972, Building 167B
| |__\ \________| |       Kingsport, TN  37662       615/229-4904
|                 |       INTERNET:   ornitz@kodak.com
 -----------------
Newsgroups: sci.electronics
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: why is one prong on plug wider than the other?
Date: Fri, 9 Oct 1992 20:42:49 GMT
Organization: U of Toronto Zoology

In article <1992Oct9.012645.17219@athena.cs.uga.edu> mcovingt@aisun3.ai.uga.edu (Michael Covington) writes:
>One side of the line is grounded to the earth so that the potential between
>line and ground will never be excessively high; this is a safety measure...

However, don't confuse the "neutral" side of the line with ground.  Sure,
it's grounded -- at the pole, or at best where the wires enter the building.
But a simple application of Ohm's Law will tell you that when there is
current flowing through that wire, especially when there's a lot of current
involved, points elsewhere on that wire are *not* at ground, not quite.
In my old apartment (in a high-rise beehive) I measured neutral at
something like 10V with respect to ground, which is certainly enough
to be dangerous, given the amperage available.

The reason that the plugs are polarized is that if you must expose one
side of the line in some way, the neutral side is less dangerous.  Not
safe; less dangerous.  For example, in a standard (North American) light
socket, the neutral wire should go to the socket body and the hot wire
should go to the contact at the bottom, because people are more likely
to come into accidental contact with the body.  Mind you, the light
fixtures should be designed so you can't easily contact *either* part,
because neutral is *not* ground... but neutral is definitely less
dangerous than hot.  Somebody finally noticed that it would be nice
if plug-in appliances enforced correct connections in this regard.
-- 
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  henry@zoo.toronto.edu  utzoo!henry
Newsgroups: sci.electronics
From: laird@stable.ecn.purdue.edu (Kyler Laird)
Subject: Continuous Tone Signaling on CB
Organization: Purdue University Engineering Computer Network
Date:  7 Oct 92 19:20:13 GMT

We're too cheap to buy a bunch of FM transceivers for our farm,
so we're stuck with CB's.  I'm tired of listening to the crap
that comes in off of I-65, so I thought I might try adding CTS
to all of the units (~10).  A few questions come to mind...

	1. Is CTS legal on CB frequencies?

	2. What is the best CTS frequency to use?

	3. Can I use a 555 alone to generate the signal, or will
		I need filters.

	4. How do I detect and filter out the CTS on the receiver?

	5. Are there circuit board level devices available
		(inexpensively) that will perform these functions?

	6. How are you doing today?

Thanks!

--kyler
From: jeh@cmkrnl.com
Newsgroups: sci.electronics
Subject: Re: variable speed/pitch cd decks modification?
Date: 15 Oct 92 03:34:02 GMT
Organization: Kernel Mode Consulting, San Diego, CA

In article <06cM02bT263G01@JUTS.ccc.amdahl.com>, drp40@cd.amdahl.com (Doug Puchalski) writes:
> I asked this question on the net a year or two ago and someone said
> that Denon had a player out there with a pitch control on it.  I never
> saw one though.  Perhaps it was a "studio" type player?  I say that because
> I doubt they would market such a player for normal home usage--there just
> wouldn't be a demand for it.

No, they were "consumer" units.  Almost all of the Denon line of CD players
last year had variable speed (not just pitch!) control.  Don't know if they
still do. 

	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
uucp 'g' protocol guru and release coordinator, VMSnet (DECUS uucp) W.G., and 
Chair, VMS Programming and Internals Working Group, U.S. DECUS VAX Systems SIG 
Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
Uucp:  ...{crash,eisner,uunet}!cmkrnl!jeh
From: lsg001@cck.coventry.ac.uk (Graham Wilson)
Newsgroups: sci.electronics
Subject: Re: Voice-operated Universal Remote Control
Date: 15 Oct 92 11:35:01 GMT
Organization: Legal Department - Coventry University

In article <Bw2p6H.8DD@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <1992Oct13.152506.3101@venice.sedd.trw.com> gay@venice.sedd.trw.com (Lance Gay) writes:
>>I just heard an advertisement on the radio for a voice-operated universal
>>remote control.  The sample in the advertisement was to speak the words
>>"RECORD CHANNEL 2 SUNDAY 9 P.M. TO 11 P.M.", which would set your VCR
>>to record a movie...
>
>Careful... unless somebody's made a breakthrough, such devices typically
>have either a high reject rate ("huh? sorry, I didn't catch that") or a
>high error rate ("you say you want me to turn the toaster on at 3AM?").
>They're toys, not practical appliances.


** They recently appeared on the UK television programme "Tomorrow's World".
   The remote control  has to learn your voice first. It can accept up to 
   4 people's voices. The system seems to work quite well and is quite 
   effective.



   
-- 
          ****************************************************
          *      Graham Wilson      *  lsg001@uk.ac.cov.cck  *
          *     LL.B.  Law  III     *  Coventry  University  *
          ****************************************************
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Source for Intel 82586 Ethernet chip
Date: 8 Oct 1992 17:20:44 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com

Subject says it all, I'm looking for a mailorder source for the 82586
Intel Ethernet controller chip (one-off). An idea of price would be
helpful too.

Thanks

Steve


-- 
Steve McKinty
SUN Microsystems ICNC
38240 Meylan, France
email: smckinty@france.sun.com	   BIX: smckinty