Solid state spark gap

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Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi All,

I have been thinking about SSgaps (I guess we need yet another new
abbreviation :-))

SSgap = Solid State gap ?

I have sketched up an idea I am going to experiment with at:

http://hot-streamer-dot-com/temp/SSgap.gif

It is simply an LMC555 CMOS timer triggered by a light pulse from a cheap
plastic fiber optic cable link.  The pulse width can be varied from about
50 to 500uS.  The timer runs an IGBT that is in parallel with a fancy
reverse diode and MOV.  Obviously, such a thing needs to be pretty blowup
proof since it ain't cheap.  It will probably only do 1000 volts at 100
amps peak as is but I am hoping such sections can be strung together.  I
guess for a MMSSgap :-))  I think higher currents are just a matter of
paralleling more IGBTs and diodes.

It would be easy to generate triggered light pulses synced to the AC line
with a set delay to set the notch quenching if such a thing could work.  A
separate controller could generate precise light signals to any number of
sections.  Probably not the world's cheapest type of gap but very cool to
play with.  I figure it is best to keep it really simple and as cheap as
possible.

All the parts are from Digi-Key too which makes finding parts easy if not
cheap :-)  I am going to order some parts up and start playing.  I think I
have all the measurement tools collected to study this stuff easily
including my nice 10:1 Pearson 1Hz to 20MHz current monitor I just got off
E-bay :-))  Perfect of catching the current spike through the IGBT right
before it explodes :-))

I am no genius when it comes to this stuff, but gotta start somewhere...
Obviously, many unknowns and this is all just pie-in-the-sky untested stuff
but I thought I would throw it out there.

Stay tuned....

Cheers,

	Terry