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Re: Jelly Beans and more!

The power supply I use is built in the following manner.  The ideas  
are based on fairly well known circuit ideas (I public domained one circuit 
diagram in 1981). This is not a balanced working model. It's a prototype 
for exploring solid state supplies since it does many things under different 
circumstances:

A 555 chip drives a power NPN. Frequency range approx 500hz-1khz.
The duty cycle (non-diode version) prefers the high stage as small as 
possible but can tolerate it the other way as well.  I have a pot 
that fine adjusts the high pulse and a larger pot on the second stage.  I drive a small 
(5W is a good starting point) audio speaker transformer (can you get 
these anymore?) hooked up in reverse i.e.  the thin coil (which is usually 
just 1 turn). Switching is from ground (the reverse works as well).  You can get 
quite a wallop using a car ignition coil instead but you should trade 
your transistor up to a horizontal frequency power NPN.  At that 
point you may as well also start playing with higher frequencies and 
flyback coils.

I see the above as pulsating DC causing an AC output by virtue of the 
harmonics that are generated (somewhat similar to a Tesla coil). But this 
area is not my strong point. Perhaps Tom and/or Telford could comment.

Anyway, monkey around with the controls - and this is one way to
 get jelly beans (particularly in small diameter tubes.)


Kenny



> On Wed, 17 Apr 1996 Kenny@NeonShop.com wrote:
> 
> > Whew! Jelly Beans can get complicated sometimes.
> > I just figured we had a resonant circuit causing standing waves. 
> > I've created jelly beans using middle audible frequencies 500hz-1khz 
> > and can get them to flow one way or another by varying the duty 
> > cycle.
> 
> Interesting!  Dan mentioned that attempts have been made to produce
> jellybean-based neon chase effects, but the tube characteristics drift
> too much to make this reliable.  Anyone have experience with this?  If
> there was a great demand for a neon chaser, it might not be impossible to
> add some sort of feedback to a high frequency supply to stabilize the
> motion effects.
> 
> "jellybeans" appear in DC Geisler tubes in the form of the "striated
> column", the discharge that fills the main part of the tube.  I played
> with them in a 1in diameter tube.  They appeared as a stack of disks, like
> evenly spaced glowing quarters.
> 
> I suspect that the main discharge in any gas tube is always composed of
> jellybeans, but the AC voltage sweeps them back and forth so fast that
> they aren't perceptable by humans.  Unless those humans sweep their eyes
> rapidly back and forth, whack themselves repeatedly upside their heads, or
> mount their gas tubes on motorized rotors and light them through slip ring
> connections.
> 
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> 
Kenny Greenberg --  Neon - Scenic and Environmental Art  
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