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Re: Why does top capacitance work?



Hi Steve,
            You write....

> I must be suffering from a misconception about top capacitance - i.e.
> the toroid.  People talk about putting a larger toroid on top as a way
> to get a larger spark.  The claim is that the larger toroid has to
> charge up to a higher voltage before breaking out.
> 
> The problem I have with this, is that the coil will be resonating with
> an A.C. voltage, at 50 kHz or 100 kHz or whatever.  So, won't the top
> capacitance charge and discharge at the same rate?

Indeed. But max amplitude is reached over several cycles of 
oscillation according to the value of k the system is set at.

> I would think the average voltage would be zero.  (I know I'm 
> wrong here - I've seen the > sparks!)

Instantaneous voltage is what we are concerned with.
 
> So what is going on?  Is there some sort of rectification effect here?
> Can anyone tell me what they think a plot of the voltage versus time
> would look like assuming we could hook a strip-chart recorder to our
> tesla coil and record the instantaneous voltage?  Or do we get an
> oscillation that builds over time where eventually the swing exceeds
> the breakdown voltage?  This seems like the most likely description to
> me.

Agree.

Malcolm