Resonant Frequency Calculation


I thought I would mention that I have a program I wrote at my web site that
is pretty good and calculating the resonant frequency of a Tesla coil
secondary system given a bunch of physical dimensions.  The file has the
code and an explanation of how it finds the values...




At 01:57 PM 8/8/99 +0100, you wrote:
>The excessive Cself and Ctop readings are due to the fact that you can't
>actually measure them with a conventional LCR meter, due to the fact that
>(a) for Cself the meter will not magically 'forget' the inductive reactance
>of the coil and (b) for Ctop you need to reference this against a good
>ground while it is away from all other objects, and the stray C in the
>measuring circuit will be very significant. 
>I think that Cself can only be measured by taking the self-resonant
>freqency of the sec. alone then putting a reference cap across it and
>measuring again. You can then use simutaneous equations (the simple tuned
>circuit one) to determine the Cself. I think you need to know the
>inductance first though - but your measurement here should be OK.
>For Ctop I think you can use a similar technique - just work it out from
>the drop in frequency when you add the toroid to the bare coil. This may
>give you more realistic values.
>Your pictures are very good and show some lovely streamer shapes. However
>you have heavy corona from your top turn so you may want to lower the
>toroid a bit more. Also, is that a hot-spot on the bottom of your secondary
>or just a reflection? If it's inter-turn arcing I'd investigate carefully.
>Alex Crow