Re: Modulation+Plasma Tubes(Was Stereo amplifier)

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Original poster: "S Gaeta by way of Terry Fritz <teslalist-at-qwest-dot-net>" <sgtporky-at-prodigy-dot-net>

Hi Steve,

The acoustic standing waves causing the broken appearance of the plasma
makes sense, so you have probably solved that mystery. I can't figure out
the color changes either. It might be due to the presence of several
different gasses in the tube, but I can't figure out why different audio
freqs would cause different ones to ionize more than the other. Perhaps its
a duty cycle kind of thing. Lower frequencies might give some of the gasses
time to de-ionize between pulses, while the ionization of other gasses tends
to persist between those same pulses.  Sounds like I need to have a talk
with Bill Connery - someone I know that makes plasma tubes, globes, and
crackle tubes. He could probably shed some light on this. (I know, bad pun!)

Bill, are you on this list?

Sue

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, March 09, 2003 4:19 PM
Subject: Re: Modulation+Plasma Tubes(Was Stereo amplifier)


 > Original poster: "Stephen Conner by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>
 >
 > At 16:00 08/03/03 -0700, you wrote:
 > >As the audio frequency
 > >was swept from 20 Hz to 20KHz, the plasma in the tube went through
dramatic
 > >changes in both color and appearance! There was a few audio frequencies
that
 > >caused the plasma to break up into a series of beads! The RF frequency
 > >didn't seem to matter, it was actually the audio modulation that caused
the
 > >changes!
 >
 > As far as I know this is 'Acoustic Arc Resonance'. As the name suggests
 > it's an acoustic standing wave set up inside the discharge tube by the
 > audio modulation. I first read about it in a designer's manual for
 > high-frequency lighting ballasts. I also saw it once when I was playing
 > around with one of those electronic switching NSTs and an old piece of
neon
 > tubing. I don't know about the colour changes, though.
 >
 > Steve C.
 >
 >
 >