HDTenEightyP/NetNews huggingface dataset:
From: magus@inqmind.bison.mb.ca (James Copland)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 9 Apr 92 13:38:19 GMT
Organization: The Inquiring Mind  1 204 488-1607

danube@dirac.physics.sunsyb.edu (Dan Koller*) writes:

>    The following works rather nicely, and can be made small.  I found an
> old DEC monitor a year ago, stripped the CRT and threw the rest in the
> junk box.  Recently it occurred to me the HV section probably could be
> made to work.  I just traced the +12V and ground pins and hooked it up.
> I removed the HV rectifier and I had a 15KV or so Tesla coil in 5 minutes!
> It's sufficiently powerful to make a 3-4" high Jacob's Ladder, and if you
> like PC board art, the extra components look kind of neat on this 
> particular board.  If it runs in this fashion without burning up for more
> than 20 min., I'll put the whole thing up on the wall, probably with
> a neon display of some sort.  Good luck.
> 							Danube

Yes!  But its not "truly" a Tesla coil until you include the "rotary 
spark gap" in the primary circuit.  I have used B/W tv high voltage 
sections and gotten 7 - 18 KV and color ones ranged for me from 20 - 
48Kv.  Nominal is B/W 15KV and color 40KV so you can see most of them are 
lower than the nominal.  They make great Jacobs ladders and other Tesla 
type toys.  I like the "Plasma Ball" the best, as you can safely interact 
with the lightning.  Now if I could only use some electronics to build 
the equivalent "solid state"  spark gap!

Regards,
magus.

magus@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
From: mann@eskimo.celestial.com (Tom Mann)
Newsgroups: sci.electronics
Subject: Question about bypassing TV r.f. circuits
Keywords: baseband video, tv rf - if
Date: 6 Apr 92 14:52:56 GMT
Distribution: na
Organization: <<< ESKIMO NORTH (206)-FOR-EVER >>>


Has anyone had any experience modifying tv sets so that the video
from a vcr is introduced into the video circuits directly rather
than going through the rf & if circuits. Intuition tells me that
the picture would be much better if I got away from all of the
distortion
introduced by those circuits.
-- 
-------------------------------------------------------------------------------
|Tom "Old" Mann	 KD9NL/7 Kirkland, Wash.                   		      |
|									      |
| Since I am un-employed, no one is responsible for my opinions.              |
Newsgroups: sci.electronics
From: jeffj@krfiny.uucp (J. Jonas)
Subject: Re: parallel port distance limits?
Organization: Jeff's house of computer pieces
Date: Mon, 13 Apr 1992 17:13:03 GMT

In article <7806@cayman.COM> pgf@cayman.COM (Paul Fox) writes:
>	How far can a typical PC's parallel port be extended?  I haven't
>	looked at the drivers...  I'd love to go about 50 feet...

I've used a 50 foot parallel printer cable for years with no problems.
It's an old one with real thick wires and a real shield (not a ribbon cable).
You need to be a real snake charmer to handle this thick black cable.
Even the ribbon cables are probably OK because the signal wires
are between grounded wires.  Just keep the cable away from
transformers, fluorescent lamps, etc. to avoid problems
with transmitting/receiving RF.

- Jeffrey Jonas
jeffj@synsys.uucp

From: tomb@hplsla.hp.com (Tom Bruhns)
Date: Wed, 1 Apr 1992 18:57:28 GMT
Subject: Re: Blocking out a radio station
Organization: HP Lake Stevens, WA
Newsgroups: sci.electronics

wtm@uhura.neoucom.edu (Bill Mayhew) writes:

>A very effective way to trap out an annoying signal is to build a
>1/4 wavelength stub transmission line.  The stub can be connected
>directly across the antenna terminals of the receiver.  The far end
>of the stub should be shorted.  The stub will reflect energy over a
>distance of 1/2 wavelength.  This means that you'll be adding back
>energy 180 degrees out of phase at the antenna terminals (at one
>very specific frequency).  A tuned stub, if carefully constucted
>has a very high Q factor.  

A 1/4 wave stub shorted at the free end will look like an "open"
(at the frequency at which it's 1/4 wave electrically), not a
short.  But even if you open the free end to yield a short at the 
resonant freq., I question whether you will be able to get a high
enough Q with a reasonable (e.g., RG-8 or smaller) transmission 
line resonator for the (200kHz/100MHz) problem.  It'll still look 
too much like a short 200kHz away from resonance to be much good.  
A helical resonator shunted by an appropriate L or C to yield a 
transmission pole on the desired station and zero on the undesired 
might do the trick.  See ham publications about repeaters:  they
have a similar problem at 150MHz with 600kHz spacing, where they 
need (well) in excess of 60dB attenuation of one of the pair and 
want less than 2 or 3 dB attenuation of the other.
Newsgroups: sci.electronics
From: cayz@barney.cis.udel.edu (James Cayz)
Subject: Project Rough Estimate Needed - Where?
Organization: University of Delaware, Newark
Distribution: usa
Date: Tue, 14 Apr 1992 02:09:54 GMT


Hi All,

	I have an electronics project that I, as a computer specialist, can
invision in my head, and actually name a couple of the key parts contained
within, but I don't know who to call to get an estimate on the actual creation
thereof?  Is there a "Professional Dreams to Reality" business out there, and
if so, what is the 800 number ?

	Umm, if anyone out there tinkers (or actually works with) LCD displays,
and interfaces them to PC compatible computers, and has about 10 minutes of
time, and would like to help on a personal level, please drop me a note...

	I don't need exact figures, just "ballpark" ones.

	Please, I don't get enough time to read the "essential" bbses, like
comp.virus, so, please, reply directly to me at cayz@cis.udel.edu

	Thank you
	James Cayz
Newsgroups: sci.electronics
From: zerr@schaefer.math.wisc.edu (Troy Zerr)
Subject: Re: Home EEG- HELP me read brainwaves!
Summary: Look at HAL in 1988 BYTE 
Keywords: HAL EEG Brainwaves
Reply-To: zerr@math.wisc.edu (Troy Zerr)
Organization: Univ. of Wisconsin Dept. of Mathematics
Date: Mon, 13 Apr 92 14:56:54 GMT

Ciarcia's circuit cellar did a couple of articles on just such a device--
Look in the June and July 1988 issues of BYTE magazine.
(In fact, I think a kit may still be available from Circuit Cellar Inc.)

(And for goodness sake, whatever you do, make sure that you have
optoisolators between you and anything powered by AC current or a transformer!)

-- Troy Zerr
zerr@math.wisc.edu
From: mdgoodma@CRDEC8.APGEA.ARMY.MIL (Mack Goodman)
Newsgroups: sci.electronics
Subject: Help with Chips?  I need to know if these are worth saving.....
Date: 7 Apr 92 13:57:23 GMT


I have some old boards lying around that I must throw out.  These
boards have chips on them that LOOK like they might still be
worth something.

Could someone tell me something about these chips and whether or not
they are useful in today's world?

Intel  D8085A  5D474  INTEL '76
Intel  P8212   D1171  INTEL '74
Intel  P8253-5 5D054        '76
Intel  P8216   D1159
Intel  D2716   951B3  Intel '77

If they are, how much would they be worth? 

Just a long shot but I hate to throw away stuff like this......

Mack

Thanks.......
mdgoodma@crdec8.apgea.army.mil
Newsgroups: sci.electronics
From: jdg@devine.ColumbiaSC.NCR.COM (Jim Griggers)
Subject: Plotting with PADS-Shareware
Originator: jdg@devine.ColumbiaSC.NCR.COM
Organization: none
Date: Tue, 07 Apr 92 17:28:04 GMT

I can't seem to get the shareware version of PADS Logic to plot
anything.  I have read the part about plotting in the install.doc
and have followed their instructions under "Pen Plotter Does Not Work".

My system just hangs and has to be rebooted to exit from this condition.

I am monitoring the RS-232 lines and CTS is active.  No data at all is
transmitted.

Anyone else solved this problem?

BTW: I can plot just fine from TANGO.  I can also plot from a BASIC program.

Jim Griggers   jdg@devine.columbiasc.ncr.com
From: berger@atropa (Mike Berger)
Newsgroups: sci.electronics
Subject: Re: Ohm's law for AC?
Date: 13 Apr 92 21:18:19 GMT
Article-I.D.: ux1.1992Apr13.211819.24043
Organization: University of Illinois at Urbana

"Raymond C. Chick" <rc4n+@andrew.cmu.edu> writes:
>I record classical music and have recently begun to investigate the
>affects of cable resistance on mic. level audio signals.  I used two
>cables, one about 20' and the other about 350'.  I passed identical
>signals through each cable and measured the  outputs levels for various
>frequencies.  I found no difference in output level between the two
>cables for frequencies from 100Hz. to 16Khz. Yet, the restistance of the
>short cable was .5 ohms and the long cable was 5.5 ohms.

>Shouldn't the long cable attenuate the signal or even roll of the high
>frequencies?
*----
That's what I would have expected.  Which leads to the next question:
How did you measure the signal strength and frequency response?
--
	Mike Berger
	Department of Statistics, University of Illinois
	AT&TNET     217-244-6067
	Internet    berger@atropa.stat.uiuc.edu
From: printf@cix.compulink.co.uk (Ian Stirling)
Newsgroups: sci.electronics
Subject: Telescope drive systems
Date: 13 Apr 92 02:03:48 GMT
Reply-To: Ian Stirling <printf@cix.compulink.co.uk>
Organization: Gated to News by demon.co.uk

I recently acquired some incremental rotary encoders when a local
disk srive manufacturer shut down. I have two unused HP 1000 pulses/rev
encoders and one ROD 800 made in germany by "DR JOHANNES HEIDENHAIN".
This is about 6 inches diameter and two deep. I believe it to be a 18000
pulses/rev incremental encoder. I have a calibration note for it too.
Mail me if interested.
Mail to either                        
Printf@cix.compulink.co.uk  Should work.
Printf%cix@ukc.ac.uk        2nd best  
Printf@cix.uucp             last hope.
(Ian Stirling).
From: schuster@panix.com (Michael Schuster)
Newsgroups: sci.electronics
Subject: Re: Parallel and Serial Ports
Date: 9 Apr 92 22:38:16 GMT
Organization: PANIX - Public Access Unix Systems of NY

In article <1992Apr7.004707.29179@athena.cs.uga.edu> mcovingt@athena.cs.uga.edu (Michael A. Covington) writes:
>
>Parallel ports are much faster than serial ports, which is why the
>external disk drive connects to the parallel port rather than the
>serial port.
>
I've noticed on the specs of the Trantor parallel port-to-SCSI adaptor that
writes (i.e. output from the parallel port) are twice as fast as reads
("input" via the parallel port). Does this mean the "input" is kludged?



-- 
_______________________________Mike Schuster________________________________
NY Public Access UNIX: schuster@panix.com        | 70346.1745@CompuServe.COM
The Portal (R) System: schuster@cup.portal.com   | MCI Mail,GEnie: MSCHUSTER
From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics
Subject: Re: Parallel and Serial Ports
Date: 10 Apr 92 13:15:55 GMT
Organization: Acorn Computers Ltd, Cambridge, UK

In article <1992Apr9.223816.1466@panix.com> schuster@panix.com (Michael Schuster) writes:
>In article <1992Apr7.004707.29179@athena.cs.uga.edu> mcovingt@athena.cs.uga.edu (Michael A. Covington) writes:
>>
>>Parallel ports are much faster than serial ports, which is why the
>>external disk drive connects to the parallel port rather than the
>>serial port.
>>
>I've noticed on the specs of the Trantor parallel port-to-SCSI adaptor that
>writes (i.e. output from the parallel port) are twice as fast as reads
>("input" via the parallel port). Does this mean the "input" is kludged?
>

It means that reads use the 4 control-input bits as inputs, taking 2 operations
per byte. Writes use the 8 output bits in one go and are therefore twice as fast. 
The remaining control-output bits are used to control the data transfer.

-adrian

f
i
l
l
e
r

-- 
--------------------------------------------------------------------------
Adrian Godwin                                        (agodwin@acorn.co.uk)
Newsgroups: sci.electronics
From: keithl@loop.uucp (Keith Lofstrom;;;520-1993)
Subject: Where to find old Tektronix manuals
Organization: KLIC
Date: Thu, 16 Apr 92 03:37:52 GMT

For all you folks looking for Tektronix oscilloscope manuals, old CRTs,
etc., there is a retired Tek engineer who has quite a stock of old Tek
manuals and such:

Deane Kidd
27270 Ladd Hill Road
Sherwood, Oregon 97140
(503) 625-7363

Deane worked at Tek for 40 years, and was the guy in charge of telling 
the rest of us we hadn't done it right yet.  He is taking care of the old
stuff because he thinks that is part of doing it right  (you can decide for
yourself what current Tek corporate policy is).  He is probably as much to
thank as anyone for the old - but still usable - Tek equipment that you 
folks are trying to scrounge parts and manuals for.  If not for him, the
stuff would have fallen apart a long time ago.

Deane sells this old stuff as a labor of love, and he isn't getting rich
doing it.  If you think his prices are too high, or that he doesn't act
like a "real businessman", you don't have to do business with him.  If
you are a connoisseur of classic instrumentation, be glad to have an 
opportunity to deal with one of the men that made it happen.

Keith
-- 
Keith Lofstrom       keithl@loop.klic.rain.com     Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Power ICs
Newsgroups: sci.electronics,cmu.cs.robotics,comp.robotics
From: n1mjr@isuvax.iastate.edu (Mike Reilly)
Subject: Re: Commodore help
Reply-To: n1mjr@isuvax.iastate.edu
Organization: Ioway State University of Technology and Economic Development
Date: Tue, 7 Apr 1992 06:36:21 GMT

In article <Yds=uYG00VolEnD0oe@andrew.cmu.edu>, fc0v+@andrew.cmu.edu
(Franklin Chang) writes: 
>Hi,
>  I was wondering if anyone knows of a simple hack that will allow the
>commodore 64 to work off dc battery supply.  I've heard that the
>computer uses the waveform off the ac powersupply as a timer.  Recently
>someone posted a solution to this problem, but it required a 60 hz (not
>Mhz) oscillator and I'm at a lost to find a 60hz oscillator.  If any can
>help, it is fairly urgent.  Our robot is going to a competition on the
>Wed 8th.
>Thanks
>Frank
>***************************
>   fc0v@andrew.cmu.edu
>     Franklin Chang
> Carnegie Mellon University
>***************************

Looking at the schematic for my C64, the power supply provides two supplies 
to the computer: a regulated 5 VDC, and an unregulated (most likely) 9 VAC.
The 9 VAC is used to provide internal 12 VDC and 5 VDC.  It's also used to 
provide power for the cassette tape port.  The 60 Hz of the 9 VAC input is 
sent to the CIAs to run their internal time-of-day clocks.  (These are 
different from the two timers on each CIA, which run off of the computer's  
~ 1 MHz clock.  These are also different from BASIC's TI$ and TI variables, 
which also run off the computer's clock, and are therefore never accurate.)
The 9 VAC-derived supplies don't show up at any of the I/O ports (user or 
cartridge) so you can't fake out the internal supplies by connecting your 
own there.

The regulated 5 VDC is no problem.  You will have to provide 9 VAC, since 
it's internally rectified and regulated.  The frequency isn't important, as 
long as you don't use the CIA time-of-day clocks.

For the 9 VAC you could possibly use a 555 driving "cross-coupled" 
transistors to reverse the polarity of a voltage applied to the 9 VAC input 
at about 60 Hz.  You may also want to run this through some sort of filter 
to round off the edges of your waveform.  (This is just a suggestion,  I 
haven't really thought it through.)

My schematic shows pin numbers for the power connector, but I don't have 
the pinout for the connector, and my connectors aren't numbered.  What I 
have is:
  pin     use
  ---     ---
  1,2,3   Ground, Shield
  4       No Connection
  5       +5V
  6       9 VAC
  7       9 VAC

April 8, eh?  Better warm up that soldering iron!  Best of luck.

Out of curiosity, I'd like to hear what you come up with.


=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
        Mike Reilly        KB0HVR         Stop the madness, Don't do EE
n1mjr@isuvax.iastate.edu        Unix. a.k.a. The emperor's new clothes.
n1.mjr@isumvs.iastate.edu   Ask me how Ioway State University of Technology
n1mjr@iastate.edu            and Economic Development is censoring Usenet.

Newsgroups: sci.electronics
From: tpappas@hamp.hampshire.edu
Subject: RE: Phone Line Audio Question
Organization: Hampshire College
Date: Fri, 10 Apr 1992 17:04:24 GMT

Its quite simple!
We use telephone audio in our studio all the time. 
And yes  it's an off the shelf design. I designed and built such a device
with scrap droor components.  I used an audio coupling transformer and a 
capacitor. The primary windings add in series to 500 ohms. Instead of 
connecting them directly together i added a cap between them. I think it 
was somthing like 0.047 micro farads with a 600vlt rating. And the 
secondary which is 500 ohms runs into the control room mixer.



           Tip   >------------/ II
                              / II /------------<
      (primary winding 1)     / II /
                              / II /
                 >-----X------/ II /
                       I        II /
         0.047 uF      =        II / -----------CT   (secondary winding)
      		       I        II /	
                >------X------/ II /                      Output Side 
                              / II /                        to Mixer
      (primary winding 2)     / II /
                              / II /-------------<
        Ring    >-------------/ II



Sorry 'bout the art work..... 

Try this circuit it works great for us in the studio. Just make sure you 
use properly rated components.

					Tom Pappas
From: v064mb9k@ubvmsb.cc.buffalo.edu (Neil Gandler)
Newsgroups: sci.electronics
Subject: Repetitive clicks when playing tapes
Date: 7 Apr 92 20:49:00 GMT
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41

I have a relatively new Marantz cassette deck and when I play tapes
I notice an annoying click sound in the background which becomes very apparent
when the music goes silent. I thought originally was mechanical but
since recently the clicking sound has spread to both decks and the left
one has gotten worse. My spectrum anylizer on my E.Q. suggests that
the clicks are in the 60hz band. But this is not even close to power
line hum. It also indicates harmonics at the higher frequencies. I
notic when I turn on dolby, it gets somewhat better. Has anyone had
a similar situation and does anyone have a solution.
               Thankyou,
                     Neil Gandler
Organization: Penn State University
Date: Monday, 6 Apr 1992 15:59:59 EDT
From: <GNR100@psuvm.psu.edu>
Newsgroups: sci.electronics
Subject: RE: commercial killer

            Does anybody have a compilation of the "Commercial Killer"
serries of postings?   I would gfreatly appreciate it if somebody could sent it
 to me.  I was making one myself, but several of my files were wiped out
recently.
                             Thank you,

                                Gordon Rogers
                                gnr100@psuvm.psu.edu
Newsgroups: sci.electronics
From: withrow@lims01.lerc.nasa.gov (JAMES WITHROW)
Subject: Re: DC Shock
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA Lewis Research Center
Date: 16 Apr 1992 14:29 EST  

In article <1992Apr12.201321.24624@ux1.cso.uiuc.edu>, berger@atropa (Mike Berger) writes...
>You're right - I wouldn't like it at all.  And it most certainly WOULD
>look like torture to me if somebody strapped a collar around me that
>could shock me at HIS discretion, and I have no control over it.

With the invisible fence, you CAN NOT "at your discretion" shock your dog!

>If owners were responsible enough to take proper care of their dogs, they
>wouldn't resort to torture devices.  Shock collars are not a constructive
>or positive way to teach a dog anything but fear.  I know many well-behaved
>dogs that didn't need pain and fear to teach them.

As you know, dog's are ANIMALS not rational humans.  I don't know any dogs 
which won't go chasing a rabbit that was sitting at the back door of the 
house, especially when the rabbit runs when the door is opened!  I believe 
that it is the responsible owners who use some type of device which 
prevents the dog from running off (ie. those with some type of restraining 
device).  I also don't know of any well-behaved male dog which will stay in 
his yard if a female dog in heat walks by.

The invisible fence collar will sound an audible tone, depending on the 
collar, for .5 to 2 seconds before you get the shock.  The shock is 
slightly worse than a cattle fence (it usually does not bother me to hold 
on to the cattle fence).  If you have an invisible fence, you don't just go 
out there to shock the hell out of your dog.  If it is done right, and the 
dog is a fast lerner, he will only get shocked a few times.  The dog will 
relate that shock to passing the boundry flags and will no longer cross 
them. 

My German Shepherd has one and she will not go past it now.  She does not 
even have to wear the collar.  We have many rabbits which visit and she 
enjoys chasing them from the yard.  She will not go across the line.  Even 
if we leave the yard, she stops.  She has the .5 sec collar and if she 
hears the tone from the collar, she backs up IMMEDIATELY.

---------------------------------------------------------------------------
Jim Withrow                         |  
NASA LeRC  MS: 333/2                |
21000 Brookpark Rd.                 |   I can't spell and I don't care!
Cleveland OH  44135  (216) 433-8315 |     withrow@lims01.lerc.nasa.gov
---------------------------------------------------------------------------
From: joeld@hpnmdla.sr.hp.com (Joel Dunsmore)
Date: Wed, 8 Apr 1992 19:29:46 GMT
Subject: Re: changing 220 line to 110
Organization: HP Network Measurements Div, Santa Rosa, CA
Newsgroups: sci.electronics

As I understand home wiring, the best solution may be to wire in
what I think is called a split phase socket.  

With 220, you have two hot lines, and one neutral line.  Each hot line
is 110 Volts to Neutral, but they are out of phase, so are 220 volts
relative to the other hot line.  For your application, you can change the
plug to wire 1 hot to one the upper outlet, and the other hot to 
the lower outlet.  That way you can draw full current from the lower
outlet even when the air conditoner is on the upper outlet.  I think
this is often done in kitchens to allow appliances such as toasters and
microwaves to be plugged into one outlet.  Caution, it requires a 
special socket (actually, most sockets have a breakoff tab to 
separate the upper hot line from the lower hot line).  Also, you need to 
be sure there is a separate ground line.  (The neutral line is actually
a ground line, that is only grounded at the junction box).

As far as current is concerned, It doesn't matter what the voltage 
from the line is, the wire can handle current based on its size.  220
Volts at 12 Amps will supply twice the POWER as 110 at 12 amps.  But
if the current is the same or lower on the new unit, no problem.

Any electrician will no far more than what I said, and you may even
find good help at a full service hardware store.  One that I go to even
as a complete mock up of house wireing to show you what to do.
From: Jeff.Lindstrom@ofa123.fidonet.org (Jeff Lindstrom)
Newsgroups: sci.electronics
Subject: TTL Protection
Date: Mon, 13 Apr 92 04:13:10 PDT
Organization: Universal Electronics Inc. (Public access BBS)

BJC>I am planning on building a digital tachometer for my truck.  BJC> I would like to 
BJC>know what kind of circuitry I would need to protect my TTL

Look in a Digi-Key catalog for Opto-Isolators.  They are made by Harris, Omron, Quality Tech., Isocom, Hewlett-Packard, and NEC.

___
     Amiga MailMan v0.9


--  

Jeff Lindstrom
Internet: Jeff.Lindstrom@ofa123.fidonet.org
Compuserve: >internet:Jeff.Lindstrom@ofa123.fidonet.org