HDTenEightyP/NetNews huggingface dataset:
From: nagle@netcom.com (John Nagle)
Newsgroups: sci.electronics
Subject: Re: Craftsmanship is dying
Date: 14 Aug 92 18:11:47 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

jeffj@krfiny.uucp (J. Jonas) writes:

>With a heavy sigh I agree that overall, craftsmanship is dying.
>I have taken apart electrical appliances since my teens and it's getting less
>and less satisfying.  Taking apart a big tube TV was a wonderful puzzle
>of interlocking parts, large chassis and spaghetti wiring.
>A lot of hand work.
>I took apart a VCR recently.  It snapped apart, the case being
>mostly plastic.  Where was the fun in that?
>There was very little I could salvage.  Too many application specific parts.

       But that IS a form of craftsmanship.  The fine detail in modern
electronics is superb.  The tolerances on connectors are far tighter
than they were in 50's gear.  Fit and finish at the board and connector
level is very tight in much modern gear.  The level of engineering design
that goes into, say, a VHS caisette shell, is well above anything seen
in '50s packaging.

       A Swatch watch is magnificent as an exercise in design for 
manufacturability.  You need a microscope to appreciate it, though.

					John Nagle
Newsgroups: sci.electronics
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: Craftsmanship is dying
Summary: well, yes and no
Organization: Jeff's house of computer pieces
Date: Wed, 12 Aug 1992 20:28:19 GMT

With a heavy sigh I agree that overall, craftsmanship is dying.
I have taken apart electrical appliances since my teens and it's getting less
and less satisfying.  Taking apart a big tube TV was a wonderful puzzle
of interlocking parts, large chassis and spaghetti wiring.
A lot of hand work.
I took apart a VCR recently.  It snapped apart, the case being
mostly plastic.  Where was the fun in that?
There was very little I could salvage.  Too many application specific parts.

Taking apart old IBM computers was fascinating.  I really admired all
the man hours that went into making those machines: the wire cables
were all LACED (anybody remember nylon lacing cord and the appropriate knots?).
It was extremely labor intensive.
The tubular steel frames were indestructable.
I still have the large core planes from the IBM 1620 and 1130.

I have the WOOD cases from lab equipment such as a GE Oscillograph,
turbidimeter, and an inductance bridge.  Wonderful hardwood cases
with furniture quality woods, finishes and hardware.

But on the down side, all that equipment took a hefty chunk of
your budget back then.
It's sad to see an EE lab where all the equipment is in cheap
plastic cases, or aluminum cases at best.
It is a small comfort that the new equipment takes a smaller
percentage of the budget, is significantly LESS expensive,
HARDER to break and much more available.
But I'd rather have 2-3 new oscilloscopes than one older one.
Even if the older one's better, increasing availability is
a good thing.  Mass producing even test equipment has put
equipment that was unaffordable only a few years ago
into the hands of many more engineers and technicians.
Overall, that's a good thing.

If computers were still hand made, the prices would still be
astronomical.  The PC 'revolution' was not just the pioneers
that were hand wiring their own computers but the ability to
mass produce the parts and make PCs a commodity.
Just go to a computer show and see the hundreds of tables with
PC compatible motherboards and peripherals, all competitively priced
(although most are no-name manufacturers from Taiwan, Korea or Japan).
Such things were possible before.

I'm saddened by the collapse of the surplus market and the disinterest
in quality built equipment, but that's progress (so they say).

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

jeffj@synsys.uucp
From: rbs@uk.ac.ed.aisb (Robert Scott)
Newsgroups: sci.electronics
Subject: Book request: audio amps
Date: 19 Aug 92 18:52:39 GMT
Reply-To: rbs@aisb.ed.ac.uk
Distribution: sci
Organization: Dept AI, Edinburgh University, Scotland


Can anyone suggest a good book on amplifier circuits:
the theory and application of.
I'd like a book with real/commercial audio amp circuits together with
an explanation of how they work and why all the compnents are in there.

I've found that most electronics books are too theoretically based
with no insight into how engineers design high quality audio amps.



--
Rob Scott
---
Department of AI                Tel: 031-650-2713
University of Edinburgh         FAX: 031-226-2730
80 South Bridge               email: rbs@aisb.ed.ac.uk
EDINBURGH
EH1 1HN
From: blackman@hodgkin.med.upenn.edu (David Blackman)
Newsgroups: sci.electronics
Subject: PC-based Logic State Analyzers
Date: 20 Aug 92 23:06:44 GMT
Organization: University of Pennsylvania

I am looking for any recommendations for PC-based logic state
analyzers.  I have literature from Link Computer Graphics Inc. and
ZTest/V^3.  Are these analyzers any good?  Are there any other vendors to
consider?

-- 
David Blackman
blackman@hodgkin.med.upenn.edu
(215) 898-3553
From: fridberg@alcvax.pfc.mit.edu
Newsgroups: sci.electronics
Subject: RE: Why are 8 bit TTL binary counters so hard to find???
Date: 15 Aug 92 17:50:12 GMT
Organization: MIT PLASMA FUSION CENTER

In a previous article, jon_sree@world.std.com (Jon Sreekanth) wrote:
>In article <1992Aug13.212738.26715@julian.uwo.ca> wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
> 
>   I found a 74XX867 in an old TI data book, but no one has this chip.
>   So like how come there are so few 8 bit anything in high-speed
>   TTL?  I'd even pay $5 for a 16 bit TTL binary counter (32 MHz min.),
>   But I doubt they exist...
> 
>Maybe you could use a PAL or GAL like 22V10 ?
> 
>Why is it important to get an 8 bit counter in one package, as 
>opposed to tying two 4-bit counters together ? 
> 
>/ Jon Sreekanth

I were able to buy 74ALS867 from distrubutor called Wyle Labs in Billerica, MA.
They send it to me in 2 days and they were the less expencive too. (compare to 
NewArk, Arrow and other big guys). You best bet would be to call to TI and ask
them who might carry this kind of IC. As about reasons to use 8-bit counter ins-
tead of 4-bit ones in my case it was the size of IC. 2 4-bit counters would 
take almost twice as much space as 1 8-bit counter and if you need lots of them
on one board...I am at home now and dont have address of Wyle Labs handy, so if
you can't find it yourself let me know and i'll find it when im at work.
Mike
From: markz@ssc.wa.com (Mark Zenier)
Newsgroups: sci.electronics
Subject: Re: EIA-232 cable length restrictions
Date: 18 Aug 92 22:57:10 GMT
Organization: SSC, Inc.,  Seattle, WA
X-Newsreader: Tin 1.1 PL3

jep@miles.com (Joseph Perry) writes:
: I'm trying to determine the maximum cable length for EIA-232 connections.  
: EIA-232 specifies that the effective shunt capacitance of the receiver 
: side of the interchange circuit be no more that 2500 picofarads.
: .... 
: Have I missed something in my measurements and analysis or is the EIA-232
: standard overly conservative in limiting cable length?

"Technical Aspects of Data Communication" by John E. McNamara,
published by Digital, has an appendix on "How Far - How Fast?"
with charts for various schemes like rs-232, 422, 423 and 20 milliamp
loops.  (At least the 1978 edition does.)

There is also similar information in some editions of the databooks
for Interface integrated circuits from Texas Instruments.

Mark Zenier  markz@ssc.wa.com
From: jfw@ksr.com (John F. Woods)
Newsgroups: sci.electronics
Subject: Re: SMT training kits
Date: 13 Aug 92 13:32:12 EDT

nagle@netcom.com (John Nagle) writes:
>rwc@ius4.ius.cs.cmu.edu (Randy Casciola) writes:
>>I have recently begun to design surface mount PCBs and would
>>like to find a kit that might include small samples of adhesives,
>>solder pastes, sample PCBs and a few components, and possibly a
>>"how to" manual for soldering SMT boards.
>        I saw some SMT training kits at Active Electronics in Santa Clara
>a few months ago.  Very possibly they were the old Vector kits.

It's listed in the new Active Electronics catalog as item SMT-KI ($42.90),
and contains (at least) a 3.5"x4" FR4 circuit board, a bunch of ICs,
several resistors, and a box; there's no mention of adhesives, solder, or even
a manual, but I'd assume it has at least the last :-).  I think it is from
OK Industries, but that's only on the grounds that everything else on the
page is :-).

Not the president, just a client :-).

Newsgroups: sci.electronics
From: mpaul@unlinfo.unl.edu (marxhausen paul)
Subject: Re: Are Seagate Hard Drives any Good ?
Organization: University of Nebraska - Lincoln
Distribution: usa
Date: Tue, 18 Aug 1992 12:36:13 GMT

Our electronics shop in the University of Nebraska College of Engineering
does a fair amount of computer repair, and we've had poor experiences with
Seagate ST- series drives and don't recommend them.  The computer I'm
using right now I dare not power down; the Seagate hard drive in it may
or may not spin up again if I do.

--
===============================================================================
paul marxhausen                              \/               grace 
university of nebraska - lincoln             /\              happens           
===============================================================================
Newsgroups: sci.electronics
From: knop@dutecag.et.tudelft.nl (Peter Knoppers)
Subject: Re: Simple transistor project (Q)
Organization: Delft University of Technology, Dept. of Electrical Engineering
Date: Mon, 17 Aug 1992 12:24:38 GMT

jimc@tau-ceti.isc-br.com (Jim Cathey) writes:

>In article <1992Aug14.114202.3925@donau.et.tudelft.nl> knop@dutecag.et.tudelft.nl (Peter Knoppers) writes:
>>If it is not possible to ensure that the input signal is low at the
>>end of the 1 second period, you'll have to add some logic that switches
>>off the trigger signal of the 555 after it has been started until the
>>logic input signal has gone low again.

>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.

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.

Peter Knoppers - knop@duteca.et.tudelft.nl
From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics
Subject: Fluke 75 DVM - fault or bug in current measurement
Date: 18 Aug 92 17:18:50 GMT
Organization: Acorn Computers Ltd, Cambridge, UK


I've just repaired an intermittent fault on a Fluke 75 DVM (series I), and
found another peculiarity : but I'm not sure if it's a fault or a bug.

If approx. 3A is passed through the 10A and COM terminals with autorange
selected, it is measured correctly. The meter selects the xx.xx range.
However, if the range is forced to xxx.x (I don't think this can happen
on autorange), the meter displays about 1.4A.
If 30mA is passed through the 300mA and COM terminals, a correct display
occurs whichever range is selected.

This doesn't occur on a Fluke 77, but the circuitry differs slightly (the
75 has a PCB dated 1983, and 2 fuses - the 77 has a PCB dated 1985, only 1
fuse, and a different layout). Could the error be due to some peculiarity of
the resistor network used to provide the 2 current ranges (and ignored,
as it isn't particularly useful to select this range) or is there another
fault to fix ?

The previous owner of the meter appears to have deliberately disabled the
range hold feature by cutting away the conductive rubber pad from the button, 
and had put a blanking plug in the 10A socket, possibly because of concern over 
this misreading - but apart from this peculiarity, it seems to work OK.

-adrian
From: krueger@cal.enst.fr (Martin Krueger)
Newsgroups: sci.electronics
Subject: Re: "Super-CD" ... soon ?
Date: 14 Aug 92 08:31:49 GMT
Organization: Telecom Paris

In article <712556100snx@black.demon.co.uk> tchannon@black.demon.co.uk (Tim
Channon) writes:

>
>Do you have any idea of what >90dB dynamic range really means?
>

I've once seen a chart explaining the usable dynamic range of a compact disc in
professional use (with 16 bit depht). What I remember is :

1)  On the upper end of the theoretical 90dB range they have to cut off 10dB as
a clipping reserve, since digital clipping would immediatly destroy a whole
recording.

2)  You cannot really use the lower 30-40dB of the 90dB range, since distorsion
becomes too high (up to 40% in the first 10db range, as far as I remember). The
reason for this is the decreasing resolution of the sampling device at lower
input levels.

Thus the reamining usable dynamic range of a compact disc doesn't exceed
40-50dB, that is still a lot but can be outperformed by analog recordings.


	M A R T I N
From: u9dmlb@ohm.york.ac.uk (Duncan McL Barclay)
Newsgroups: sci.electronics
Subject: Re: RGB Splitter for Mac?
Date: 21 Aug 92 13:27:59 GMT
Organization: Electronics Department, University of York, UK

On the same subject how much are these distribution boxes? And does
anyone know of a supplier in the UK?

Thanks

Raggy

-- 
Raggy                 | God smiles upon the little children, the alcoholics, and
u9dmlb@ohm.york.ac.uk | the permanantly stoned. S.King.
From: drmellen@vela.acs.oakland.edu (Dewayne Mellen)
Newsgroups: sci.electronics
Subject: Tec-200 film
Date: 19 Aug 92 13:31:15 GMT
Distribution: sci.electronics
Organization: Oakland University, Rochester MI.

I know this has been asked before so please forgive me, but could some
one email me an address where I can buy the Tec-200 film for making
pcb boards.  This is needed for a school project ASAP.

thanks in advance,

drmellen@vela.acs.oakland.edu
From: 880518l@dragon.acadiau.ca (Nelson Langille)
Newsgroups: sci.electronics
Subject: Re: Cable Television Descrambling
Date: 15 Aug 92 14:59:32 GMT
Distribution: sci
Organization: Acadia University

Will this descrambler work with an antenna signal, or does the signal
have to come from the cable company?
From: schuster@panix.com (Michael Schuster)
Newsgroups: sci.electronics
Subject: Re: Lithium Type 76 button batt. - any?
Date: 17 Aug 92 21:52:44 GMT
Distribution: usa
Organization: PANIX Public Access Unix & Internet, NYC

In article <7849@lee.SEAS.UCLA.EDU> dchien@boole.seas.ucla.edu (David H. Chien) writes:
>
>    I'm looking for a longer lasting Type 76 battery.  I use Silver Oxides
>now and my camera just eats them up like Apple Jacks.  Are there lithium
>replacements available?

Lithium batteries are 3V; the others are 1.5
If you have an application which uses TWO STACKED 76's, you can substitute
a DL-1/3N which is the size of two 76's stacked on top of each other.


-- 
_______________________________Mike Schuster________________________________
NY Pub. Access UNIX/Internet: schuster@panix.com | 70346.1745@CompuServe.COM
The Portal (R) System: schuster@cup.portal.com   | MCI Mail,GEnie: MSCHUSTER
From: jcw@kd4dts.dixie.com (John C. Wren)
Newsgroups: sci.electronics
Subject: Re: How hot can the 486-50 cpu run ?
Date: 22 Aug 92 00:03:29 GMT
Organization: kd4dts

Get this.  Some information we got hold of says that the 586 (yes, *5*86)
is currently running at 18 watts...   Lets cook some eggs, eh?

-- 
--------------------------------------------------------------------------------
John C. Wren (kd4dts)			|  Word Prefect 5.0:  The choice of
jcw@kd4dts.dixie.com			|    religious scribes everywhere.
..!emory!rsiatl!kd4dts!jcw		|
Organization: Penn State University
Date: Thu, 20 Aug 1992 02:50:14 EDT
From: <FWR100@psuvm.psu.edu>
Newsgroups: sci.electronics
Subject: Re: Are Seagate Hard Drives any Good ?
Distribution: usa


In article <1992Aug12.005008.24806@ariel.ec.usf.edu>,
fevrier@sunburn.ec.usf.edu. (Ian Fevrier (EE)) says:
>
>Recently I had a local computer dealer  try to convince me that Seagate
>drives are not worth the metal they're built with.
>Have any of you lived through personal experiences that substantiates
>this dealers claim ?

My experiences with two Seagate drives...

ST-238 - Ran about 5 years, started developing Data Errors, many bad sectors,
         etc.  I guess this is about what I'd expect from this generation drive

ST-277 - In 2 years has crashed a _minimum_ of 5 times, including once 2 weeks
         ago, and again this week.  Usually a hard sector error develops in the
         FAT, so it really fouls up everything.

I don't know if this performance is typical, but I'm not taking any more
chances with Seagate drives. I have a Maxtor drive on back-order, they're
supposedly very good - 150,000hr MTBF, and the folks at Hard Drives Internat'l
said they were a very reliable drive (also the least expensive)

-Frank

Newsgroups: sci.electronics
From: pjh@mccc.edu (P. J. Holsberg)
Subject: Re: PD schematic capture, layout and route?
Organization: The College on the Other Side of U. S. 1
Date: Sat, 15 Aug 1992 01:03:52 GMT
X-Newsreader: Tin 1.1 PL4

rcain@netcom.com (Robert Cain) writes:
: I've found the real thing.  However, it does have limited capacity.
: approx 40 IC's and a 5" by 5" board.  It is schematic capture, layout
: and routing!  The best part: it's an actual PADS package from CAD Concepts
: who to my knowledge are the king of the field.  The next best part: it
: is *free*.  The add calls it shareware but they decided on freeware after
: the add.  It is fully functional, just limited capacity.  Obviously it is
: intended as a teaser for their $1500 product that has very few limits.

Actually, it's $2000. ;-)
Organization: Queen's University at Kingston
Date: Wednesday, 12 Aug 1992 14:18:39 EDT
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: 3.3 Volts

In article <-+4m4y_.rudi@netcom.com>, rudi@netcom.com (Rudolf Usselmann) says:
>
>Actually it started of with people trying to integrate more and more
>smaller and smaller transistors on a very small die (i.e. 16mb DRAMS).

At that size, the electric field associated with the higher +5V might
becomes high.  When the field strength gets too high, breakdown and
other things might happened.

>The two main advantages that you get by reducing the Voltage is that you
>can use smaller tarnsistors and that you can increase the speed (3volt swing
>The second reason is why the whole industry started to follow this trend.
Power consumptions of devices are further reduced at low voltage.  This
is especially useful in low power applications.  At lower voltages, less
power goes into charging/discharging capacitive loads & also lowers the
current when both P & N MOS are briefly switched on during transitions
from one logic state to another.

>Now this lower voltage is also used for "between chips" comunication
>for the same reasons.

Since CMOS input threshold is usually (*) 1/3 & 2/3 of power supply.
At 3.3V, VL (Max) = 1V  and VH(min) = 2V  which is very comparable to
that of standard TTL families.  It simplifies things a lot that way.
The near 0 or 3.3V outputs also keep TTL happy.

(*) Yes CMOS can be made into TTL compatible (eg. HCT, ACT), but there
are extra transistors involved.

>rudi

K. C. Lee
Elec. Eng. Grad. Student
Newsgroups: sci.electronics,alt.folklore.urban
From: schroede@bnlux1.bnl.gov (gary l. schroeder)
Subject: Re: SHOCKING STORIES
Organization: Brookhaven National Laboratory, Upton, NY 11973
Date: Thu, 13 Aug 1992 20:06:13 GMT

In article <1992Aug12.193416.25072@pony.Ingres.COM> reb@Ingres.COM (Phydeaux) writes:

>A housemate in college used this technique to 'drink' liquid nitrogen.
>He put  it  *into*  his  mouth and  as  it started down his  throat it
>expanded  and vapor  came  gushing out of his  nose  and mouth!  Quite
>an impressive trick for parties!
>					reb

Working with LN2 myself on a daily basis, I'm forced to wonder "how did
he avoid suffering frostbite on his tongue, etc.?"  While most of the
liquid will go gaseous, some must first come in contact with exposed
oral flesh.

-- 
------------------------------------------------------------------------
Gary Schroeder	                |  Warning: prolonged exposure to this
schroede@bnlux1.bnl.gov         |  .sig may cause retinal damage and 
Brookhaven National Laboratory  |  blistering skin rashes.
From: fhl@milton.u.washington.edu (Dean Pentcheff)
Newsgroups: sci.electronics
Subject: Re: GPS Availability
Date: 14 Aug 92 16:50:00 GMT
Reply-To: dean2@rocky.geol.scarolina.edu (Dean Pentcheff)
Followup-To: sci.electronics
Organization: Department of Biology, University of South Carolina, Columbia

Regarding the availability of GPS units, they most definitely are
available for land, sea, and air applications.  As mentioned by an
earlier poster, the Department of Defense "fuzzes" the signal slightly
(this is called "Selective Availability", SA for short) to prevent bad
guys from using the system for pinpoint accuracy.

The GPS system can be used by aircraft, but has not been certified by
the FCC as the sole positioning system for an aircraft.  Because not
all the satellites are up yet, there can still be times when you can't
get a good fix because too few satellites are currently in view.

Note that there _are_ units that are small enough for backpacking,
etc.  Furthermore, there are units that allow you to defeat the
Selective Availability "feature".  Basically, you have two units, one
with you (the mobile station) and one fixed (the base station).  Both
simultaneously record the same signals from the same satellites (so
they must be within about 500 km of each other).  Since the base
station doesn't move, it "knows" where it is and generates corrections
for the SA-degraded signal.  The corrections can be applied to the data
from the mobile unit, fixing the SA uncertainty.  The cheapest way to
do this is to post-process the data later on a PC, but there are units
that will broadcast the corrections in realtime ($, as you might
imagine).

I used one of these post-processing correction systems this summer off
the Florida coast (tracking lobsters, of all things) and it worked
beautifully.  The uncorrected data wander all over the place (within a
few hundred meters).  After correction, the data were _far_ tighter.  I
was most impressed.  The system we used was the Pathfinder from Trimble
Navigation (800-TRIMBLE, 408-481-8000).  They'll happily sell you one
or tell you who rents them (we rented).  Very nice system.

-Dean
From: dewey@vpdbox.austin.ibm.com (Dewey Coffman)
Newsgroups: sci.electronics
Subject: RE: How hot can the 486-50 cpu run ?
Date: 18 Aug 92 15:14:36 GMT
Reply-To: dewey@vpdbox.austin.ibm.com
Organization: IBM, Austin, TX. US of A.

In article <17AUG92.09220477@wl.aecl.ca>, jeremiahw@wl.aecl.ca writes:
|I heard that the 486 could get up to 400 deg Celcius if the appropriate program
|>was run (one designed to turn on as many transistors as possible)  I am
|>skeptical about the number 400 but needless to say it does run hot.  Many VARs
|>andOEMs have had problems designing clones simply because of the heat problem.
|>And the 586 is supposed to run even hotter!!  Isn't that awful?

	That very well may be true. I did some testing on my
	486-33 vs a 386-20 temperatures. The 486 temperature inside
	the case was 30-40 degrees warmer than the outside(ambient)
	temperature. The 386-20 was only 20 degrees warmer. I never
	had any problems with the motherboard or chip, but the
	other components(disk controller, hard drives) started acting
	flaky until I installed a $99 FanCard inside, no, no more problems.
-- 
Dewey Coffman				ibmpa!dewey@vpdbox.austin.ibm.com
Consulting @ IBM			Bldg 007, Div 44, Loc 966, Dept 06T
11400 Burnet Rd				Zip 1514, Room 1D-052
Austin, TX 78758-3493			(512) 823-6463
In article <21207@rpp386.lonestar.org>, jfh@rpp386.lonestar.org (John F. Haugh II) writes: "I'm probably a fool "