Re: PIC Based VTTC Staccato Controller

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

This PIC stuff sounds pretty neat.

About RF interference on the board.  It usually doesnt happen at low power.
When you start pushing over 12" or so, it might have a chance of occuring.
My staccato boards have never had this problem, but then again, everything 
was running on 12v.  A 5V board may be more sensitive.


>In it's current form, the PIC allows for a highly variable pulse
>output by selecting one of 3 options, and then varying them up or down
>(via 3 pushbuttons).  The options are:
>
>1) Change % of AC cycle ON (pulse-width per cycle)
>2) Change number of ON-cycles and
>3) Change number of OFF-cycles.


Also, i dont think you want to mudulate the pulse width to less then a 
plate supply pulse.  If you turn on your SCR or whatever with a high power 
VTTC, but not before the plate supply goes +, your little scr may go 
poof.  You could turn it off before the power is gone, but only with an 
SCR, since it will stay on to conduct the rest of the pulse.  But a MOSFET 
or transistor may go poof in this situation too, since it will be switching 
a good amount of power.  I would say it is best to keep things 
standard.  Of course you could use a very tough MOSFET or IGBT for the 
switching if you really want to try hard switching.

Good luck, and let us know how it comes out.  Maybe it will be a simpler 
alternative to the current staccato circuit.  Then again, it may turn out 
to be the more complex alternative to the staccato we know :)

Steve Ward.