RE: Primary resonators with very low L/C ratio

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

Original poster: "Steve Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve.conner-at-optosci-dot-com>

 >How do we construct a primary tuned circuit which has a very low L/C
 >ratio?

The main problem is of course getting the low L. It's obviously impossible
to make a coil with less than one turn, so you have to make the diameter
smaller, and eventually you'd get to a point where (a) it was too small to
couple adequately into the primary and/or (b) you would be limited by the
ESL of your capacitor bank and switch.

I did the math for a primary circuit that fires 8 Joules at 65kHz using a
charging voltage of 1kV. It uses a single turn about 11" diameter. The
capacitor bank and IGBT packages occupy one-quarter of the turn and account
for about one-quarter of the inductance. I think this is getting near the
practical upper limit.

Steve C.