HDTenEightyP/NetNews huggingface dataset:
From: rxtajp@minyos.xx.rmit.oz.au (Andrew Pettifer)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 14 Apr 92 22:06:00 GMT
Organization: RMIT Computer Centre, Melbourne Australia.

From article <1992Apr10.213234.8893@e2big.mko.dec.com>, by pierson@cimill.enet.dec.com (Dave Pierson):
> In article <kyZyiB1w164w@inqmind.bison.mb.ca>, magus@inqmind.bison.mb.ca
> (James Copland) writes, in part:
> 
>>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.
>>> 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., 
> 	A wise precaution.  Some HV supplies are not designed for high load
> 	operation. And, as has been pointed out, such things are not quiet,
> 	RF wise.  The RF may well peak at a point set by the length of the
> 	electrodes.  Some of those frequencies are used by folk who do not take
> 	kindly to emi...
> 
Would using DC reduce in any way the amount of RF generated?
Most EHT transformers in monitors nowadays, have an integral HV diode, if
you used a Leyden jar to reduce the ripple, and mounted the Jacobs ladder
within a steel mesh tube, how quiet would that be do you think?
From: kumar@acuson.com (Kumar Neelakantan)
Newsgroups: sci.electronics
Subject: RF Preamplifier design
Summary: RF Preamp
Keywords: RF preamplifier design
Date: 9 Apr 92 18:42:30 GMT
Distribution: sci
Organization: Acuson; Mountain View, California

I am looking for a design or names of companies/consultants who could design
an RF preamplifier with the following specs:

Gain: 30 dB
Input Signal Dynamic Range: 2 mV - 1.2 V pk-pk ( ~55dB )
Max Output Voltage: 36 V pk-pk
Frequency Response: Flat (100 KHz - 10 MHz) with +- 0.1 dB passband ripple
			- 3dB Frequency: 20 MHz
Impedance of input load connected to preamp: 0.5 - 1 Mohm, 3-5pF
Output Impedance: 50 ohms
Output Spectral noise density: 0.1 microVolts/sqrt. Hz with input
of preamp terminated in 50 ohm load

If you have any info call me at (415)694-5722 or send me e-mail to
kumar@acuson.com
cheers
kumar

-- 
-------------------------------------------------------------------------------
kumar neelakantan 			     uucp: ...!sun!sono!kumar			              			    internet: kumar@acuson.com        Acuson Computed Sonography, Mt.View CA	   voice: h:(415)691-0621                                                                w:(415)694-5722
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: TV and radio reception
Date: 13 Apr 92 14:26:08 GMT
Organization: University of Georgia, Athens

In article <1992Apr13.090846.8648@Princeton.EDU> goodnuff@phoenix.Princeton.EDU (David W. Goodnuff) writes:
>
>	Hello, my room-mates and I are currently suffering from poor
>radio and TV reception in our college dorm room.  I was wondering if
>anyone has any suggestions for improving our reception.  

I assume you are in a steel-framed building.  There is only one solution --
get the antenna outside the steel frame!  This can be done by clamping
something onto your window so that it's outside.  

Amplified antennas in a high-noise environment (such as inside a building)
are not a good thing; they amplify the noise along with the signal.


-- 
==========================================================================
Michael A. Covington, Ph.D. |  mcovingt@uga.cc.uga.edu  |  ham radio N4TMI
Artificial Intelligence Programs | U of Georgia | Athens, GA 30602  U.S.A.
==========================================================================
Newsgroups: sci.electronics
Subject: Re: oscilloscope manual needed
From: hbg6@phx.mcd.mot.com (John Schuch)
Date: 14 Apr 92 18:52:01 GMT
Organization: Motorola Computer Group, Tempe, Az.

In article <1992Apr7.073738.20349@maccs.dcss.mcmaster.ca> ce3wa3bc@maccs.dcss.mcmaster.ca (Tom Nosella) writes:
>I called Tektronics, but they were unable to help me find one.  

Call your University's purchasing department and get the name of the
Tektronics salesman who services the school's account. He will be MUCH
more motivated to give you a hand.

John
From: dac@dacami.UUCP (David Culberson)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Distribution: usa
Date: 6 Apr 92 18:27:15 EST
Organization: My home system.

In article <1992Apr3.074803.17749@athena.mit.edu> etsai@athena.mit.edu (Eugene C Tsai) writes:

>I have a friend who wants to build a device called a Jacob's Ladder.
>It is a device commonly seen in sci-fi/horror movies.... it has two
>metal "antenna"-like structures with a periodic electrical arc which
>spans the base of the two "antenna" and moves up the antenna. If
>anyone knows of any articles (ie in Radio Electronics) detailing the 
>construction of such a device or has actually built it, I would
>appreciate any info regarding building this Jacob's Ladder.

  Go to your local public library and check out the book _Gadgeteer's
Goldmine_ by Gordon McComb.  Call #621.381.  It details how to build many
interesting projects, among them a Jacob's Ladder, a Plasma Globe, Ven de
Graaff generator, etc.  Pretty cool book.

		-David

--
( dac@dacami.UUCP - cis.ohio-state.edu!n8emr!bluemoon!dacami!dac ) Amiga//
( - David Culberson - )  Have any old computers or terminals for sale?\X/
Xref: sparky sci.electronics:8635 rec.audio:7540 rec.audio.pro:542
From: chrisc@gold.gvg.tek.com (Chris Christensen)
Newsgroups: sci.electronics,rec.audio,rec.audio.pro
Subject: Re: VCAs wanted.
Date: 16 Apr 92 22:44:02 GMT
Followup-To: sci.electronics
Organization: Grass Valley Group, Grass Valley, CA

In article <578F02gn10.z01@JUTS.ccc.amdahl.com> kls30@DUTS.ccc.amdahl.com
writes:
>Does anyone know who makes good quality VCAs (voltage controled amps).
>I'd like to do a few things with and equalizer.
>
>Basically I plan to take an off-the-shelf 16 band equalizer with seperate
>adjustments for frequency for left and right and make a daughter board to
>convert it into a vocorder.

In this case where the absolute sonic purity isn't at stake...:-)  I 
would suggest the PMI SSM-2122.  It has two pretty good VCA's in a 16
pin package.  You will have to take into account the law of operation
for the control of the VCA's.

Also take a look at the National semi LMC835.  It is a digitally
controlled equalizer.  It is a "dual 7 band" but the sections can be
cascaded for 14 bands.  The only draw back is that the part is a
digital step attenuator.  It steps in 1 dB increments.  If you make a
large change in the setting you will get zipper noise.

This usually isn't a problem unless you do it with no signal to mask
the zips.

-- 
Chris Christensen                  The opinions I express are my own,
chrisc@gold.gvg.tek.com            and sometimes they are wrong!
916-478-3419 FAX 916-478-3887      After all, I AM only human.
From: agulhati@willamette.edu (Ashish Gulhati)
Newsgroups: sci.electronics
Subject: Re: masers from magnetrons
Date: 11 Apr 92 19:46:50 GMT
Article-I.D.: willamet.1992Apr11.194650.18694
Organization: Willamette University, Salem, OR

Excuse MY ignorance too, but what's a magnetron (I do know what a MASER is
supposed to be)?

Ashish
From: borkowsky@zodiac.rutgers.edu
Newsgroups: sci.electronics
Subject: Parallel and Serial Ports
Date: 6 Apr 92 18:47:02 GMT
Organization: Rutgers University Computing Services


	I was recently sitting in the library reading 'Computer', the
magazine by the IEEE Computer Society, and in the back they had a preview
of a battery operated, portable hard drive called Flash 25. Further on the
article stated that the arddrive gets connected to the parallel port of
the computer.

	I don't pretend to have mastery of computers (yet!), but this
struck me as strange because I always thought the parallel port was a one
way port. (If you remember, there were quite a few messages on this
newsgroup a while back about the virus in Iraq's defense computers, and if
it was possible to send a virus backward through a parallel printer port.
I believe the general concensus was no, that it was not possible.) I also
looked at a pin-out chart of my parallel port and (assuming the parallel
port is a standard) there were 8 data out pins and a bunch of not connected
pins. Is the parallel port non-standard, or has it changed recently? If not,
how is such a hard drive possible?

	And while I'm typing this, another question/personal problem comes
to mind. When not studying and such, I work part time as a bartender at a
restaurant that has a restaurant management computer system, which takes
orders and sends food orders to the kitchen and drink orders to the bar.
The computer system also will print out a report of sales at the end of the
day to either the printer or any of the terminals. However, I was asked if
it is possible to have the report sent over a modem instead.

	My basic problem is thus: The system is a completely closed system.
There is no keyboard input, making it impossible to do anything except run
the restaurant program. The host computer communicates to the seperate
order terminals using 19200bps with an RS-232 port. From what I know from
the system, it would be no problem to connect a modem to an extra port,
define it as another terminal, and call from a remote location to have
access to the system. However, if the modem is 2400bps, and there is no
way to slow down the data stream from the computer, is there anyway this
would be possible? (One idea I thought I might look into is using a serial
buffer to store the output from the computer at 19200bps and send it over
the modem at 2400bps.)

					Jason
				        (BORKOWSKY@ZODIAC.RUTGERS.EDU)
Newsgroups: sci.electronics
From: larrie@beaufort.sfu.ca (Larrie Simon Carr)
Subject: Re: Electrostatic Field Promotes Hair Growth ???
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Fri, 10 Apr 1992 18:43:47 GMT

In article <1992Apr10.153222.3176@krfiny.uucp> jeffj@krfiny.uucp (J. Jonas) writes:
>>There is currently research being done at the University of British
>>Columbia about the ability of ELECTRIC CURRENT in stimulating hair
>>growth.
>
>You mean, if I stick my finger in the light bulb socket,
>not only will my hair stand on end, but more will grow on end too?
>

No.  The setup they are using is positive probes placed on a wet
scalp and a ground attachment by your waist.

Think of it as standing in your bathtub and rubbing your head against
a light socket.

-- 
Larrie Carr                 
Engineering Science               (604) 291-4451  
Simon Fraser University           (604) 298-1050
British Columbia, Canada          larrie@sfu.ca
Newsgroups: sci.electronics
From: cab@col.hp.com (Chris Best)
Subject: Re: Jacob's Ladder
Date: Wed, 8 Apr 1992 19:55:51 GMT
Distribution: usa
Organization: your service


> >I have a friend who wants to build a device called a Jacob's Ladder.
> >It is a device commonly seen in sci-fi/horror movies.... it has two
> >metal "antenna"-like structures with a periodic electrical arc which
> >spans the base of the two "antenna" and moves up the antenna. If
> >anyone knows of any articles (ie in Radio Electronics) detailing the 
> >construction of such a device or has actually built it, I would
> >appreciate any info regarding building this Jacob's Ladder.

-----

I built one many years ago when I came across several spare neon
transformers while renovating a theatre.  

I used two 9-foot stainless steel CB antennas (just the straight 
part, without the springs) stuck in a block of wood so they formed 
a V shape, about a half inch apart at the bottom, and about a foot 
or so apart at the top.

In still air, the spark got 3-4" long (climbing as it grew) before
it went out and started again.  If you put a piece of paper in the
path of the spark, it would sometimes make little black dots as it
passed, and sometimes the spark would stop rising and just sit there
zapping the paper until it caught fire.  And speaking of fire, my
first attempt ended up burning a place in the rug, since the spark
jumped between the holes on the underside of the wood base.  I just
put another layer of wood under it to interrupt that path, and it
worked fine.

A pretty simple device, really, for the effect it produces!
From: mcnamara@vixvax.mgi.com
Newsgroups: sci.electronics
Subject: Cheap high-v caps wanted
Date: 14 Apr 92 14:47:28 GMT
Article-I.D.: vixvax.1992Apr14.094729.1770
Organization: Management Graphics, Inc.


	I have been troubleshooting my electronic air filter, and
have found that the .05 uF @ 5KV caps in the output section are
bad.  The local surplus places don't have them, and Newark wants
$26 ea. (ouch).  Any ideas for a cheaper source?

Curt McNamara			mcnamara@mgi.com
Mgmt. Graphics, Inc.
1401 E. 79th St.
Mpls., MN	55425
Newsgroups: sci.electronics
From: ray@ole.uucp (Ray Berry)
Subject: Re: Jacob's Ladder
Organization: Cascade Design Automation
Distribution: na
Date: Wed, 8 Apr 1992 16:13:47 GMT

rdi@cci632.cci.com (Rick Inzero) writes:
...
>Note that there exist some big neon sign transformers.  Mine
>is rated 15,000 volts at *3000* ma.  This most certainly would
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
	Must be a real honker- 15 KV * 3 A = 45 KVA :-).. Pray tell, how many
hundreds of pounds does it way, and for what purpose was it designed?  Curious
minds...
-- 
Ray Berry  kb7ht  ray@ole.UUCP  73407.3152@compuserve.com  /* inquire within */
From: francis@cs.adelaide.edu.au (Francis Vaughan)
Newsgroups: sci.electronics
Subject: Re: Front panel finish
Date: 9 Apr 92 04:06:55 GMT
Reply-To: francis@cs.adelaide.edu.au
Organization: Adelaide Univerity, Computer Science

In article <1992Apr7.222527@andrea-doria.ifr.ethz.ch>, vestli@ifr.ethz.ch (Sjur Jonas Vestli) writes:
|> 
|> Dear all!
|> 
|> Is there an easy and relaible way of writing on my Aluminium
|> front panel other than using rub on letters (Letraset, which
|> isn't really quick and easy anyway)?
|> For instance is there any way I could print a front panel layout
|> on my laser printer, and transfer it onto my aluminium plate?


Take it to an engraving shop. Mark out the panel and also give
them explicit instructions on what to engrave. The results are
very good. It may cost a bit more, but I always get panels
done this way now. Messing with rub on lettering is awful and
so are the results. The panel always looks like a custom build
rather than a factory job, but still looks really good.
It is also the most durable way of marking the panel.

You could try printing the layout onto a laser printer
reversed and in white on black and then ironing the pattern
onto the panel and then etching the panel through the pattern.

This might work.  Never tried it.


					Francis Vaughan
From: vestli@ifr.ethz.ch (Sjur Jonas Vestli)
Newsgroups: sci.electronics
Subject: Front panel finish
Date: 7 Apr 92 20:25:27 GMT
Reply-To: vestli@ifr.ethz.ch (Sjur Jonas Vestli)
Organization: Swiss Federal Institute of Technology - Inst. of Robotics


Dear all!

Is there an easy and relaible way of writing on my Aluminium
front panel other than using rub on letters (Letraset, which
isn't really quick and easy anyway)?
For instance is there any way I could print a front panel layout
on my laser printer, and transfer it onto my aluminium plate?

Thanks in advance.

Sjur J. Vestli
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: DC Shock
Date: 10 Apr 92 21:47:15 GMT
Organization: The Inquiring Mind  1 204 488-1607

jon@sparcplug.et.iupui.EDU (Jon Burgoyne) writes:

> I'm looking for a small circuit that could provide a shock to my dog.  This i
> to build a collar similiar to the invisible fence product.  I believe they us
> a 22.5v bat.
> 
> The RF part I can probably struggle through but producing a shock was not
> something they taught us in school.
> 
> Any help appreciated.
> 
> Jon Burgoyne
> Purdue University - Indianapolis
> jon@sparcplug.cadcam.iupui.edu

TO generate shocks, all you need is a simple clock circuit (CMOS SCHMITT 
INVERTER WITH Variable R and fixed C
Then a transistor to drive an autotransformer or simply a inductive coil 
with a small tap for the driver and the large turns for the secondary ZAP
The energy is proportion to the Inductor size and current . It can be 
fairly tiny. A low freq is only necessary <200HZ. But remember battery 
power will increase with frequency. Aar ignition coil would be overkill 
to say the least. Try it on your self before using!!!

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
From: christophe@cfmu.eurocontrol.be (Christophe Paquay)
Newsgroups: sci.electronics
Subject: Help needed: Resistor S.O.T.
Date: 7 Apr 92 14:43:16 GMT
Organization: Eurocontrol - Central Flow Management Unit
Originator: @lapwing


                                 Diode 1N4148
                            -------|<----------
                  |\       |                   |
                  | \      |      ________     |                _____
  HS -------+-----|  >o----+-----|________|----+---------------|     |
  from      |     | /             Resistor     |               | XOR |-----
  a 6845    |     |/ NOT            S.O.T.     |             |-|_____|    Burst
  CRT       |                                 === C          |  
  controler |                                  |   10nF      |
            |                                  |             |
            |                                  o 0Volt       |
            |                                                |
             ------------------------------------------------

    S.O.S. I need your help !!

    The above described scheme is extracted from a TV PAL encoder which
  I try to realize. Unfortunately, I'm facing a problem with the resistor,
  because I don't hnow its value. The only reference I have is "S.O.T.".
  If somebody is able to help me by giving any information about this
  resistor, please send me a message.
                    I'm awaiting anxiously your information.
                        
                               Many thanks in advance, C. PAQUAY
Newsgroups: sci.electronics
From: schuster@panix.com (Michael Schuster)
Subject: Re: My dead Yahama model CDX2 cd player
Date: Sun, 12 Apr 1992 01:10:49 GMT
Organization: PANIX - Public Access Unix Systems of NY
Keywords: fix it?

In article <1992Apr11.203807.24564@cbfsb.cb.att.com> wa2ise@cbnewsb.cb.att.com (robert.f.casey) writes:
>I have a dead CD player, a Yahama model CD-X2.  Got it about 8 years
>ago.  Has (or had) "Double resolution digital filter" which probably
>means 2x oversampling.  It also has 2 problems:  1st problem is a
>tendency to mistrack when playing CDs (sometimes really screws up,
>then reload the CD and it may play fine).  Lived with that for a while,
>then I bought a Magnavox with 4x oversampling.  Took the Yahama to my
>parent's house to listen to CDs I might buy in the area.  2nd problem:
>Few months later, the control function died.  Display would be all
>scrambled, it wouldn't respond to the front panel buttons, it would
>stick its tray out and not stop the tray motor, and such.  
>Took the cover off, unplugged and replugged some connectors, no good.
>
>Anyone have a similar failure on this model, and a possible fix?
>I have the newer machine, so I'm not out of CD music.  Probably
>not worth fixing?

I had a CD-X2 which was repaired =twice= for the same mistrakcing problem.
Finally I said enough is enough. Give it up ... for less than the cost
of another repair you can get a modern player which will out-perform it
in most any way. I gave it away for free to a CD-less friend, and never
looked back.

Over the years people here have commented that Yamaha CD players
often have tracking problems. One found mistracking on every Yamaha
player on a dealer's shelf. It says something.


-- 
_______________________________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: bill@hacktic.nl (Bill Squire)
Newsgroups: sci.electronics
Subject: Re: Home EEG- HELP me read brainwaves!
Date: 13 Apr 92 06:50:55 GMT

Due to tho real low frequency nature of brainwaves, almost any opamp will
work.  I know a person that made a brainwave machine using 741's!  I think
the LM308A would be a little more approiate however, and if you really want
to do it right get a PMI AMP01.  It is a good Idea to knotch the powerline
frequency of 50 or 60 Hz too.

                                                        Bill
From: deanr@sco.COM (Dean Reece)
Newsgroups: sci.electronics
Subject: Re: Phone Line Audio Question
Date: Tue, 07 Apr 92 15:54:34 GMT
Organization: The Santa Cruz Operation, Inc.


reynhout@cs.uri.edu writes:

>In article <1992Apr1.213252.9241@acsu.buffalo.edu> crawford@acsu.buffalo.edu (___Red Devil___) writes:
>>
>>I have a question about patching in a phone line (audio out) into a mixing
>>board.  You see, the radio station that I work for, here in Buffalo, is trying
>>to utilize it's phone line capabilities in order to put people on the air.  We
>>bought (for the better or worse?) a "Telephone Recorder" from Radio Shack
>>which has a phone line input, and an 1/8" mini-phono output.  When hooked up
>>to our mixing board, it results in a major humm/buzz and doesn't produce
>>adequate results.

>   I hate to sound condescending, but that's why broadcast supply houses
>sell Telephone Hybrids.  Unfortunately, they're very expensive, but you
>can adjust for nulls and get *much* better results.

Actually (I hate to sound condescending), but a hybrid has the very
special purpose of going from a "two wire" to a "4 wire" circuit.
The "nulls" have nothing to do with the application of pulling audio
off the phone line.  The nulls are used to prevent end-to-end loops
in the 4-wire circuit.

A fairly high impedance op-amp coupled through through ~200k resistors
to the phone line with the output driving an isolation transformer (or
an analog opto-isolator) should be just as effective.  I suspect the
RS circuit doesn't properly isolate the grounds (expecting the recorder
to be battery operated or isolated through the Power Transformer), or
perhaps it doesn't provide the correct impedance for the mixing board.

Oh, BTW you should not have the circuit above connected except
while the phone is Off-Hook (a current sensitive relay would be
ideal).

>   The parts inside one of these hybrids would run about $50.  Perhaps
>slightly more.  (Then again, the thing you bought from Radio Shack has a
>parts value of $4, and you spent ~$20 for it... :-)

True (the plastic case was most of the $4.00 :-)

>   There aren't many applications for pulling audio off of a telephone line.
>If there were, you'd see cheaper hybrids.  As with most other broadcast
>equipment, unfortunately.

Modems do it all the time (with low S/N ratios) for a few bucks.  I've
got the schematic of such a system (DAA to audio).  Its a bit much
for ascii, but I'll try if there is enough interest.

>   Andrew

-deanr@sco.com (Dean Reece)