HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.electronics
Subject: uA741C replacement
From: Rick Jansen <SSCPRICK@HASARA11.BITNET>
Date: Tuesday, 15 Sep 1992 12:58:29 CET
Organization: SARA - Stichting Academisch Rekencentrum Amsterdam

I'm going to do a project in which a lot of uA741C's
are used (some 70 at least). Now, the 741 isn't the
most up-to-date opamp any more these days. With this
number of chips it doesn't cost much more to simply
replace the 741's by another, more up-to-date chip,
for example the TL070, LF351 or LF356. (The 356 can
be used, as no offset adjustments are done anywhere.)
 
Any comments or other 741 replacements that fit in
without modifying the circuit? Disadvantages?
The project is an analog modular synthesizer, so
low-noise and temperature stability are definately pros.
 
-Rick.
 
--------------- cut here ----- here ------- or here -----------
Rick Jansen                  | e-mail: Rick@SARA.NL
SARA System Support Dept.    |         SSCPRICK@HASARA11.Bitnet
 
Space is a) something containing nothing
         b) nothing containing everything
from A Scientific Encyclopaedia For The Enquiring Young Nome
by Angalo de Haberdasheri
From: bartnik@acsu.buffalo.edu (David Bartnik)
Newsgroups: sci.electronics
Subject: Noise Conditioner/Sleep Machine
Date: 11 Sep 92 18:37:27 GMT
Organization: State University of New York at Buffalo/Comp Sci

I am looking for schematics and info for putting together one of those
noise conditioners that you find at electronics stores in the mall.  All
these things are are white noise generators that fade in and out to
produce a sound similar to waves, or you can set them to just put out a
constant sound.  It's been a few years since I looked at any sound
generator chips so any help would be greatly appreciated.  Feel free to
send email if you like.  Thanks.

 
Dave Bartnik
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Fri, 11 Sep 1992 20:48:09 GMT
Subject: Re: Circuit to multiply audio signals wanted.
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: sci.electronics


What you're looking for is generally called a "balanced" modulator (or
mixer); it is, among other things, used extensively in generating
single-sideband radio transmissions.  As a good starting place, I'd
recommend the American Radio Relay League (ARRL) "Radio Amateur's Handbook".



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
From: wrs@mcshh.Hanse.DE (Wolfgang R. Schulz)
Subject: Re: NTSC to PAL Did anyone try?
Organization: Point of Presence & MCS Hamburg
Date: Sun, 6 Sep 1992 16:36:25 GMT

cscc13@judy.uh.edu (NAVEED IQBAL) writes:

>Did anyone try converting NTSC to PAL system? 
>I hear some people does the conversion but I don't know how.

>Naveed
>NIqbal@uh.edu

Naveed:
I do it every day. The most versatile gear for it, if you are
content with Home Video Quality like VHS and don't have to deal
with Broadcast Quality, is the Panasonic AG-W1 VCR, which play
and records in all standards, and has a digital standards converter
builtin. The price is around $1,700 (47st.Photo NY for instance).
That is the machine I've got and am very happy with.

In Far East, Sharp sells a VCR for even less (some $1,200), which
even has a tuner builtin, while the Panasonic does not.

Sharp also sells a stand-alone digital standards converter, strangely
enough only iast ($500) and in SWEDEN ($1,000), in no other
country.

Regards,
Wolfgang
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: Need to know about appl. that could use EMI shielding
Keywords: EMI, shielding,
Date: Fri, 04 Sep 92 20:26:10 CDT
Organization: The Inquiring Mind BBS  1 204 488-1607

ame@matt.ksu.ksu.edu (Abdulrahman M El-Koubysi) writes:

> 
> I am trying to put together a list of applications that could possibly use
> some shield from low frequency electromagnetic interference (EMI). Dose 
> anybody out there know of an application that could be improved if shielded f
> EMI????
> 
> 
> A. R. El-Koubysi          | Internet: ame@matt.ksu.ksu.edu
> College of Engineering    | Bitnet  : ame@ksuvm
> 147, Seaton Hall, KSU     | Phone   : (913) 532-5580 
> Manhattan, KS 66506       | Fax     : (913) 532-6944 
> 

How LOW can you get.....that is ULF VLF LF HF VHF UHF...
There are lots of needs for shielding from 60 Hz EMI. too numerous to 
mention. such as most electronic circuits with high impedances, need a 
ground plane or other EMI shield.
EMI shielding covers a broad gamit from Protection methods such as 
circuits to improve common mode noise rejection...to SUPPRESSION methods 
such as using toroidal chokes or filters to PREVENTION methods such as 
eliminating the source of EMI.  The examples of these categories can, 
well fill a book. Find a book written someone from Bell Labs in the 
mid-70's It was exc.

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: NTSC transmission over phone lines?
Organization: San Diego State University
Date: Sat, 5 Sep 1992 17:36:04 GMT

In article <Bu319s.FzL@CAM.ORG> warren@CAM.ORG (Robert Warren) writes:
>From: warren@CAM.ORG (Robert Warren)
>Subject: NTSC transmission over phone lines?
>Date: 5 Sep 92 01:53:51 GMT
>Howdy all,
>	I've been trying to work out a way to send a NTSC signal via phone
>lines. I have been so far succesfull in transmitting it via a twisted pair,
>but a phone line is a new ball game. Is there any way I can send video using a
>transformer to isolate the DC from the line?
>
>What would be the easiest way to do it? Would it be easier to run it over a 4
>wire telco hybrid?
>
>Answer (news/email) are welcome. I'll summerise if intrest is shown.
>
>Regards,
>	Robert Warren
>	warren@cam.org

The DC on the line is your least problem. Get some information about MPEG. 
This is motion picture transmission over phone line, but the standard and 
chips are not out yet. JPEG, for freez frame will give you some insight how 
it is done.

Peace and Prosperity!
  ---==< 110 >==---
Newsgroups: sci.electronics,rec.video
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Macrovision
Followup-To: sci.electronics
Summary: Copying your Macrovision-protected tapes, successfully
Organization: Arizona State University
Date: Tue, 15 Sep 1992 03:40:09 GMT

 killeen@spcvxb.spc.edu (Jeff Killeen) writes:
......
> Sony GV-8/200/300/500's have long ago discovered this happy fact.  Also I 
> believe all Beta units are safe from Macrovision.
> And if case you are thinking of it...
> 	VHS tape -> 8mm tape -> VHS tape
> .... won't cut out the Macrovision.  Even though 8mm VCR will play the tape 
> back fine it still records the Macrovision junk.

I work for Go-Video in Scottsdale, AZ. We make a Dual-Deck VHS VCR. Having
both transports/electronics in ONE chassis lets you connect as many signals
between the two transports as you want, not just CompositeVideo. And
copying EVERYTHING on the tape, including Macrovision pulses, is one thing
the DualDeck does well. Call Stan Brown, @ (602) 998-3400
Allen Sullivan
From: Ted_Eugene_Viens@cup.portal.com
Newsgroups: sci.electronics
Subject: Re: capacitors
Date: Sun,  6 Sep 92 15:52:37 PDT
Organization: The Portal System (TM)

>
>Anyone know where I can get good size electrolytics?
>Low ERS, Panasonic SU or TS series would be good.
>i.e.  220uf @ 300V, etc.
>Thanks!!
>
>
>
>--
>--------------
>
>rob
>uhcc
>
Hello, Rob.

Digi-Key Corp. of Thief River Falls, Minnesota is an excellent source of
Panasonic Capacitors.  They are fast and low priced.
Call them at 1-800-344-4539.
Good luck...  Ted..

Ted Viens.
From: mmpjh@angelo.amd.com (Javed Hussain)
Newsgroups: sci.electronics
Subject: Inof/ lead for Home Burglar Alarm and EPROM programer circuits
Date: 11 Sep 92 16:31:16 GMT
Distribution: usa
Organization: Advanced Micro Devices, Santa Clara, CA

Hello netland Fellows:
I am looking for some good circuits for home burglar alarm which I can build and also EPROM programer. Any lead to sources of magazines / books will be appriciated.
Please email me or post here.

Thanks,

Javed      mmpjh@amd.com
Newsgroups: sci.electronics
Subject: Geiger counter plans?
From: gac@orion (G. Andy Cordonier)
Date: Thu, 3 Sep 92 18:23:33 GMT
Distribution: sci.electronics
Organization: Shell Oil

What is the principle behind a Geiger (ionizing radiation) counter?  I'd
like to build one, if possible.  Does anyone have any plans they could
share?  Thanks


-- 
Andy Cordonier  \ Any resemblence between my opinions and those of my
(gac@shell.com) \ employer is purely coincidental (or is it fate?).
                             \  "Any sufficiently advanced bullsh*t 
                              \  is indistinguishable from fact."
Newsgroups: sci.electronics
From: steve@nuchat.sccsi.com (Steve Nuchia)
Subject: Re: BCD-binary conversion
Organization: South Coast Computing Services, Inc.  Houston
Date: Sun, 13 Sep 1992 15:09:07 GMT

[5 BCD digits -> 16 bit binary]

You could do it iteratively if you have a good binary->bcd part.
The bit multiplexing would still take a few parts, but that will
be a problem no matter what you use.

Sounds like an ideal application for a tiny micro (like the 'K05 kit).
-- 
Steve Nuchia      South Coast Computing Services, Inc.      (713) 661-3301
Newsgroups: sci.electronics
From: suresh@papaya.iss.nus.sg (Suresh Thennarangam - Research Scholar)
Subject: What is PMPO ?
Originator: suresh@papaya
Organization: Institute of Systems Science, NUS, Singapore
Date: Mon, 14 Sep 1992 03:59:19 GMT

What exactly does the PMPO figure that many Japanese audio equipment
manufacturers use to advertise their products ?

I believe it expands to Peak Music Power Output.

How is PMPO  related to the RMS value of the power output ?

My new AIWA set is supposed to be a 400 W PMPO system. Does that
mean it can deliver 400 Watts of power ? I find that hard to 
believe.



      __
     (_       o_   o  o |_
     __)/(_( _) (_(_ /_)| )_


***************************************************************************
* Suresh Thennarangam               *  EMail: suresh@iss.nus.sg(Internet) *
* Research Scholar                  *         ISSST@NUSVM.BITNET          *
* Institute Of Systems Science      *  Tel:  (065) 772 2588.              *
* National University Of Singapore  *  Facs.: (065) 778 2571          *
* Heng Mui Keng Terrace             *  Telex: ISSNUS RS 39988             *
* Singapore 0511.                   *                                     *
***************************************************************************
Newsgroups: sci.electronics
From: jet@fokus.gmd.de (J. Tiemann)
Subject: Re: Pull ups on data bus
Organization: GMD-Fokus (Berlin)
Date: Fri, 11 Sep 1992 13:47:32 GMT

In article <1992Sep11.090525.8360@bernina.ethz.ch>, stettbac@isibee3 (Juerg Stettbacher) writes:
|>
|> Three stateable address and control buses generally need pull ups, to
|> prevent from accidental accesses. I suppose that's true.
|> 
|> But what about data buses. Can a floating data bus cause any troubles?
|> (Oscillating, switching currents .. ?)
|> 

There are three reasons for terminating a bus:

1) Improve the speed and the reliability of a bus system by avoiding
   refections. Impedance mismatch between the bus line and the open
   end of the bus line can cause signal reflections. So you have to
   slow down your bus or put on the open ends terminators with the
   bus impedance. The impedance of a VMEbus is about 20-100 ohms,
   and it is terminated with about 194 ohm. The experienced designer
   thinks thats close enough.

2) As you mentioned, the control lines can be used by several bus masters.
   There are two possiblities: 3-state and open-collector bus control
   lines. With 3-state lines there have to  be a default state, if no bus 
   master takes the bus. With open-collector lines the terminator is a
   'pull-up' while all bus master have only the possiblity to 'pull-down'.

3) CMOS components should not have an open input. A CMOS component have
   a very high input resistance so static electricity can damage the
   component. The input stage of a CMOS gate consists of two complementary
   transistors and a floating input can cause both transitors to work
   analog, that means open half (digital: one is open, one is closed). 
   This cause a high current from Vcc to GND through the cuircut, which
   can be damaged. The expirienced designer never trust an on chip protection.
   Most buses a TTL-compatible and don't use CMOS receiver. An
   exception is the Sbus (SUN-Sparc), with is designed for CMOS.
   So the SBus controller may terminate the Sbus with 10 kohm to Vcc
   and a SBus slave may include a 100 kohm resistor between the signal
   and Vcc.

Jens
From: tgg@otter.hpl.hp.com (Tom Gardner)
Date: Mon, 7 Sep 1992 17:38:35 GMT
Subject: Re: substitution of logic families
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Newsgroups: sci.electronics

|Can LS, ALS, and CMOS (pin compatible) components be substituted
|for TTL parts in general?  I've got an "old" TTL system that needs
|a couple of spare parts, do I need to agonize over speed, power, fan out
|rise times.......or are the newer logic families always "better"?

No. You must agonise. Particularly important are:
	- i/o voltage levels if you change ttl to/from cmos
	- hold times for flip flops, if you change to a faster family
	- edge rates causing ringing and false triggering, if the two
	  way propagation delay along a track is > the rise or fall time
	  (assume propagation velocity = 0.45c)
	- power supply spikes, if there is poor quality decoupling
	- ground bounce

tom "there is no such thing as digital logic" gardner

Newsgroups: sci.electronics
From: lmbrown@vela.acs.oakland.edu (lmbrown)
Subject: Answer to BNC question (with an actual REFERENCE!)
Keywords: BNC, TNC, name origin
Organization: Oakland University, Rochester MI.
Date: Fri, 11 Sep 1992 18:35:03 GMT

From ppagel@arrl.org Thu Sep 10 09:58:21 1992
Received: from mgate (port4.hartford.pub-ip.psi.net) by vela.acs.oakland.edu with SMTP id AA01679
  (5.65c+/IDA-1.4.4); Thu, 10 Sep 1992 09:55:15 -0400
Return-Path: <ppagel@arrl.org>
Received: from pkp by mgate with SMTP
	id AA44524 ; Wed, 09 Sep 92 16:46:04 EST
Date: Wed, 09 Sep 92 15:10:35 EDT
Message-Id: <52@pkp>
From: ppagel@arrl.org (Paul Pagel)
Reply-To: pkp%pkp%mgate@port4.hartford.pub-ip.psi.net
To: lmbrown@vela.acs.oakland.edu
Subject: Re: Question about origin of name of BNC connector
Status: OR

You can find the origin of the names of BNC, TNC, etc in an 
article entitled "A Designer's Guide to RF Connector Selection,"
RF Design, September/October 1980.

BNC stands for bayonet Neill-Councelman, named after Paul Neill
of Bell Labs and Carl Concelman.

Sincerely,

Paul
N1FB


Thank you for sharing this.  It certainly explains the letters AND you
include a reference.

Len Brown
Lab Manager
School of Engineering and Computer Science
Oakland University, Rochester, Michigan
lmbrown@vela.acs.oakland.edu
From: michael@vk2bea.UUCP (Michael G. Katzmann)
Newsgroups: sci.electronics
Subject: Re: Where does snow come from?
Date: 9 Sep 92 13:45:43 GMT
Reply-To: michael@vk2bea.UUCP (Michael G. Katzmann)
Organization: Broadcast Sports Technology, Crofton. Maryland.

In article <etxansk.715946468@garbod20> etxansk@garbo.ericsson.se writes:
>
> I'm wondering where the snowy screen information comes from, on a TV
>set that isn't receiving any real RF video signal.
>
> Is the snow "in the air" or does it only exist in the TV's tuner?
>

Most of it is generated by the active devices in the front-end amplifier
of the tuner (shot-noise, thermal noise etc..), some is just the accumulated
background noise from all the man made sources (finite probability that
a photon from even the weakest transmitter will reach your set), and a
few percent is the remnents of the big-bang. (4K background radiation)
(probably many other natural sources as well).

If you disconnect your antenna, you'll see the difference between the
internally generated noise and the background (usually not much difference).



-- 
Michael Katzmann	  >	Broadcast Sports Technology Inc.
~~~~~~~~~~~~~~~~	 <	Crofton, Maryland. U.S.A
Amateur Radio Stations:   >
NV3Z / VK2BEA / G4NYV	 <	opel!vk2bea!michael@uunet.uu.net
Newsgroups: sci.electronics
From: pdivine@unixg.ubc.ca (Patrick Devine)
Subject: 9 Pin / 25 Pin layouts
Organization: University of British Columbia, Vancouver, B.C., Canada
Date: Mon, 14 Sep 1992 04:56:49 GMT

Can someone please mail me pin layouts for both 9 and 25 pin serial ports?
(or atleast tell me where to find them) .. 

also:  Is the joystick port on an Atari STF (not the new analog ones) or an
Amiga basicly similiar to a 9 pin serial port?  Can you send me the pin
layout for this awell?

I'm wondering if you could hook up serial devices through the joystick
port with the proper drivers.

What I am basicly trying to do is set up a small network between my 386
and Atari STF.  I see limitations because of the Atari's 1 serial port and
1 parrallel port.  If anyone has tried something similiar, drop me a note
aswell.

thanks for the help.

-- 
|  The Postman Pat Show                featuring  o industrial strength noise |
|  PO Box 75115                                   o clips from all of your    |
|  White Rock, BC                                   favorite tv shows!        |
|  Canada,  V4A 9M4  (send for catalog)           o Loops! & Loops! & Loops!  |
From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics
Subject: Re: Filtering TV Commercials
Date: 7 Sep 92 12:32:34 GMT
Organization: Acorn Computers Ltd, Cambridge, UK

In article <55550028@hpscit.sc.hp.com}  rkarlqu@hpscit.sc.hp.com (Rick Karlquist) writes:
} Actually, now that all new TV sets will be closed-caption ready
} and commercials are starting to be captioned, you should be able
} to build a system that monitors the ASCII in the captions and
} looks for keywords (such as tradenames) to eliminate commercials.
} You could also eliminate "bullshit" by adding keywords relating
} to what you define as such.  I wish I could search for keywords
} relating to abortion and gun control and filter talk shows so
} I wouldn't have to hear the same old arguments on those topics
} rehashed for the nth time.

Yes ! a 'kill' file for TV !

I'd would need an alarm though, so that my attention could be brought
back to the TV for the 5 minutes a day when something got through the
filters ....

Note to the person writing an FAQ for this group .. can adkillers go
in there please, along with ECM for police radar as discussed-to-death ?
I nominate the 'most effective solution' for adkillers to be the 
suggestion made last time around : that an adkiller service be supplied,
via dialup line or pager channel, with kill signals generated by a team of 
dedicated kids and a majority voting circuit.


-adrian

-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.
Newsgroups: sci.electronics
From: jem21176@uxa.cso.uiuc.edu (Jon E. Meyer)
Subject: Re: halogen lamp died, what is wrong?
Organization: University of Illinois at Urbana
Date: Sun, 6 Sep 1992 18:37:55 GMT

jim@heart.seas.upenn.edu (Jim Streicher) writes:



>My halogen light recently died.

>It is rated at 500 watts and requires a "Type J" bulb.
>I replaced the bulb with a 300 watt one but nothing on the
>package indicated a "type J". Nevertheless, it fit nicely
>into the socket.

>The lamp still doesn't work.

I had the same problem, but this time when I put a 500W bulb in a
300W rated lamp.

>Does anyone know what might be wrong? Do I need to
>find a bulb that specifically says 500 watts type J?

That shouldn't be a problem.

>Should I try replacing the fuse?

That may or may not be it.  I have a dimmer switch in mine,
and it was very touchy after about a month.  I took it out completely
and so it's either on or off.  That was last august and it's
been working fine since then.  Never fixed the switch.

>I know I am not supposed to touch the bulb with my
>hands but other that that, I don't know anything about
>these lamps. Are they unreliable? Is there something else
>I could check?

Another person I know also had the same problem about a month after
she bought it.  In both our cases I think a component in the dimmer
circuit got too hot and burnt out.  Make a good guess at which one
it could be in your lamp, and go from there.

>---
>Jim Streicher                                         (215) 898-8099
>jim@heart.seas.upenn.edu (best)                       Dept. of Bioengineering
>jim@thrombus.seas.upenn.edu (forwarded to heart)      U. of Penn.
>streiche@eniac.seas.upenn.edu (forwarded to heart)    Philadelphia, PA. 19104 

Good luck fixing the thing.

Jon Meyer
jem21176@uxa.cso.uiuc.edu
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: Re: Modifying vga cards f
Date: 12 Sep 92 23:29:38 GMT
X-Maildoor: WaflineMail 1.00r


   Geoff Thomas was whineing about 'Modifying vga cards for p',
   on [09-11-92  08:26] to All!
 GT> 1) How can I cram 2 VGA cards into a PC, and have them independently
 GT> addressable? Because of the way DOS handles it's video address space,
 GT> only one card can reside in the video address space, but what if, on a
 GT> 3/486 the other card could be given a different address space that
 GT> doesn't clash with the first, and could be addressed via protected
 GT> mode on the 3/486.

    You can have 2 VGA cards in place except that one must be
    mono and the other color.

 GT> 2) Any ideas on how to give the VGA card a flat video memory, rather
 GT> than a paged one?

    Well sic et non.  Local bus provides the full 32 bit address
    space and the video boards for it do also.  They are memory
    mapped (and configurable as such).

 GT> 3) Lastly, is it possible to speed up writes to the video address
 GT> space? Currently its quite slow, and I want to speed it up.

    you can use the DMA to copy data VERY fast.  The nice thing
    about this is thier is no need to worry about memory refresh
    during the DMA xfer just make sure you transfer > =256 bytes
    each time.

My suggestion is you look into local bus.  From what I hear the
writes are 32bit and at full cpu speed.  SO you have 4 bytes
written at 7 cycles each that would give you 18.857mega bytes per
second write speed at 33mhz.  Of course thier would be some VGA
card limitations to memory access but you can beat the speed!

        Stephen Cyberman@Toz.Buffalo.NY.US
        Scripted at Sat  09-12-1992  10:30:18

... The OFFICIAL tagline of the 1996 Olympics! NOT!
--- Blue Wave/QWK v2.10