Re: Solid State Spark Gaps

To: tesla-at-pupman-dot-com
Subject: Re: Solid State Spark Gaps
From: "Harri \"Haba\" Suomalainen" <haba-at-cc.hut.fi>
Date: Sat, 21 Sep 1996 15:30:51 +0300 (EET DST)

> From: "G.E. Leyh" <leyh-at-ix-dot-netcom-dot-com>
> The primary reason that high peak capacity devices such as SCRs and GTOs
> have not been applied to fast pulsed power applications (such as Tesla Coils)
> is due to their di/dt limitation, which for a good inverter grade GTO is
> about 500 amps/uS.  A typical TC has primary current risetimes on the order
> of 1000 to 2000 amps/uS.  

That is vertainly a very good point. I did not think the rise time
limit when suggesting series use. I should have.

> area away from the gate structure, when the GTO is fired. However, A new 
> gate design called the 'interdigitated gate structure' promises to raise this
> di/dt limit significantly.  At work we are testing such a device, which is
> called the Modified GTO.  At present, the device will hold off 4200V, and 
> switch pulsed currents of over 50,000 amps peak, at risetimes of 15,000 A/uS!!

Wow! I'd just love to get a handfull of free samples on those! :) :) :)
They sound like ideal for coiling. However, I assume they are definately
hard-to-find parts which cost awfull lot. :(

> rotary gap drops about 1200V at 2000A, and takes over 200uS to quench.  The 
> MGTO at work (stacked appropriately) would drop about 10V, and 'quench' in 20uS.

They certainly would be ideal. They would also make nice effect in
a solid-state driver I assume :) BTW, as MGTOs are good for fast
rise times are they usable in the high switching frequency as well?

> to play 'Claire de Lune' on my coil.

Define 'Claire de Lune'.
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