Re: Slow Wave Helical Resonator Experiment

I am planning to build a big TC with a DC tank supply (20 kV DC 1A max). I
would like to control both quenching time (and phase) as well as bang
repetition rate. This becomes complicated with a rotary spark gap.

Can you please post some more info about your MOSFET switch: schematics,
max current substained, etc.?

tesla-at-pupman-dot-com on 09.12.98 23:00:11

To:   tesla-at-pupman-dot-com
cc:    (bcc: Marco Denicolai/MARTIS)
Subject:  Re: Slow Wave Helical Resonator Experiment

Original Poster: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>

I performed the experiments with a gap consisting of a bank of
MOSFETs. I could quench anywhere I liked in the cycle which an
ordinary gap cannot do. Quenching at a zero current crossing (peak
cap charge for whatever energy remains in the primary) resulted in a
quiet quench. Quenching at zero voltage (and current maximum)
generated the most horrendous voltage spikes across the "gap" (which
would have reignited a real gap had it dared to go out under this
condition). I have real scope photos of this which I have posted to
others. The secondary didn't care a fig where I quenched. There is a
very simple explanation for this. At the low coupling constants we
use, the primary flux is mostly coupled to the primary and impresses
itself back onto the primary.