[sdiy] Visible Tube Organ

[Toby Paddock]

Scott,
Good description. 
Now I think I get it. With 2 bulbs 
in series, the point between them where the 
pulse comes in is high impedance. With the one 
bulb idea I was going to try, the trigger 
pulse would have to pull up the bulb AND it's 
capacitor.

Just saw another reason for 2 bulbs. The pulse 
from the previous stage would be negative. Pulls 
down the voltage and makes the top bulb fire. My 
one bulb circuit would be a *soft anti-sync*.

Later,
Toby

Scott Gravenhorst wrote:
> Interesting.
> 
> I'll take a wild crack at it --
> 
> What I will describe depends very much on the frequency at which
> it is supposed to operate and that would determine the value of
> the Cs and Rs.  The single stage looks suspiciously like a
> relaxation oscillator, but with two series neon bulbs instead of
> the usual one.  This would have the effect of doubling the
> voltage at which bulbs would turn on and discharge the two
> series caps to the right of the bulb chain.  The bottom bulb is
> coupled to the input, this means that when the previous stage
> discharges, it gets a kick to attempt to push it over it's flash
> threshhold voltage.  But if the R feeding the cap/bulb network
> is set to an RC time constant of slightly more time than twice
> input frequency, the bottom bulb will not turn on due to
> insufficient voltage across it's terminals.  On the next input
> cycle, however, the series caps across the bulbs will now be
> charged to a value much closer to the flash voltage of both
> bulbs and the kick from the input is now enough to put it over
> the edge, they both conduct, discharge the caps and deliver a
> pulse to the next stage.  Everything depends very much on the Rs
> and Cs proper values.
> 
> 
> Ok, EEs, tear me apart, but I bet I'm pretty close.
> 
> 
> Toby Paddock <tpaddock at seanet.com> wrote:
> >http://www.kitphoenixx.freeserve.co.uk/project_2.htm
> >Neon Gas Tube Frequency Dividers Project
> >
> >I can't quite see what it's doing. I can see how 
> >you could have a neon relaxation oscillator 
> >with an additional charge *thump* from another 
> >oscillator. If the period of the neon osc is 
> >longer, then it is likely to trigger during one 
> >of the *thumps*. Kind of a soft sync. And that 
> >would be a division of the *thumping oscillator*.
> >
> >One of the things I want to try, because 
> >it's time for a ...
> >
> >NEON REVIVAL
> >
> >Later,
> >Toby
> >
> >Scott Gravenhorst wrote:
> >> "neon dividers" ?  Is this a neon bulb flipflop that does the
> >> divide by two thing ?  I'd _love_ to see a schematic of that
> >> part!
> >> 
> >> Toby Paddock <tpaddock at seanet.com> wrote:
> >> >
> >> >Assuming that subject line makes it past 
> >> >the spam filters...
> >> >
> >> >Did someone post about someone who took the 
> >> >tone generator from an organ and put it in 
> >> >display box? It would have been a year or so ago.
> >> >
> >> >After the interesting organ talk lately, I took 
> >> >a look inside my old Lowery LSL tube organ. 
> >> >The neon dividers light up when you play it. 
> >> >Cool. I was thinking that in an alternate 
> >> >universe - where I had much more time, energy, 
> >> >focus, brains, and I could actually play 
> >> >keyboard - I would put the hang the tone chassis 
> >> >in a plexiglass box seperate from the keyboards.
> >> >
> >> >Then later that started sounding familiar, like I 
> >> >had heard that somewhere. Like probably here.
> >> >
> >> >?
> >> >
> >> >Later,
> >> >Toby
> >> >Paddock
> >> >
> >> 
> >
> >
> 
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