RE: Zener SSTC?

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

 > Original poster: Chris Roberts <quezacotl_14000000000000-at-yahoo-dot-com>
 >
 > Hi everybody,
 > We all know that a conventional tesla coil uses a spark gap
 > that fires and
 > switches the current whenever the voltage builds high enough, but has
 > anybody ever thought about using zener diodes to replace the
 > spark gap?
 > Zeners do the exact same thing, but allow you to fire more reliably,
 > (wouldn't have to worry much about misfires) and I would
 > think that they
 > wouldn't have as many losses related to them either. So has
 > anybody thought
 > about making a "conventional" coil (tank capacitor, primary,
 > etc.) but
 > replacing the sparkgap with zeners? You could also get away
 > with using a
 > really low voltage since you don't need it to break the air
 > gap. Mabye a
 > simpler OLTC? Would you be able to get zeners rated for that
 > kind of thing?
 > Anybody else think that this could work?
 >
 >
 > -Chris

Nice idea but wont work.

When a Zener goes into reverse conduction it will maintain it's rated "Zener
voltage" across the diode. ie. a 15kV Zener will conduct at 15kV and the
voltage across it will stay close to 15kV (high "gap" losses, V*I).

A spark gap will break over at a voltage then conduct at close to 0v across
the gap as the arc forms a short circuit. i.e. a gap set to ~5mm will break
over at 15kV then maintain ~0V across it (low "gap" losses V*I) while
conducting.

Tom L.