Re: Sold state IGBT disruptive coil spark gap idea

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Original poster: stork <stork@xxxxxxxxxxxxxxxxxxx>



> You have to be careful to turn up the variac until is just starts to 
> run smoothly (120 BPS) and no more.  If you turn up the voltage too 
> high, the BPS rate can go up dramatically and overheat the 
> IGBTs.  Higher BPS does not seem to increase spark length other than 
> making them sound funny.  Sort of "screetchy".
> Thanks for everyone's help, input, and encouragement!!!  Looks like 
> we all have a new toy :-))))

Terry,

Sidacs are interesting.  Even more interesting are programmable 
unijunctional transistors or PUTs.  PUTS are a misnomer because they 
are not unijunctional transistors, but are kin to thyristors.  The 
neat part about them is triggering voltage can be set or varied with 
a simple resistive voltage divider.  Instead of multiple fixed input 
sidacs only one voltage divider controls the PUT.  It's 
programability allows it to function over a wide variety of input 
voltages.  Parts count goes down, it's cheaper to build and it offers 
better control.

stork