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caps

 * Original msg to: usa-tesla-at-usa-dot-net

Quoting tweagan-at-maind.dnet.dupont-dot-com:

> I wonder if anyone can give me their opinion as to whether cap
> size is influenced by power through the system? I understand 
> that the L/C of the tank circuit for tuning is all important 
> but with the support of high inductance pri coils the 
> capacitance is getting small (<.01uF). Is this advisable or is
> there a rule to follow?

> For example, a 15 turn pri by my calc is around 200uH.If my sec
> is to resonate at 200KHz then my cap is around .005uF!Have I 
> missed something? 

You probably won't run with your primary tapped all the way out
unless your coil system is near peaked to perfection. You
typically will find good operation with the primary tapped out
between 8-12 turns, and excellent operation over 12 turns. This
assumes you are using a large toroid discharge terminal...

Which reminds me. Recheck your secondary parameters. Are you
figuring this using the 1/4 wave resonate frequency of the bare
coil? Any discharger you add will drop the resonate frequency of
the secondary, allowing you to use a larger capacitor while still
tapping way out on the primary. It is not unusual for a decent
sized toroid to reduce the resonate frequency of the secondary
coil 50 kilohertz or more.

Richard Quick


... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12