Re: TC question

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:

> Original poster: "Darin Willson" <darinwil-at-execpc-dot-com>
> 
> I was wondering,
> since the ground and the topload act as a capcitor, could one take and
> instead of using a topload & ground
> hook the leads to another cap? like the schematic on the following link?
> http://my.voyager-dot-net/~darin.willson/tc.gif

This drawing is usually just a model using discrete components that
allows calculations that explain how the Tesla coil works (to a 
reasonable degree of approximation). If you build this circuit,
it will surely work as a Tesla coil, but you will have a big
problem if you try to build the secondary capacitor with enough
insulation for many 100s of kilovolts. It's usually a distributed
capacitor formed by the self-capacitance of the secondary coil and
its top terminal.
 
> If you can then what would happen if you made another primary and secondary
> that are resonant at the first
> coils Freq  and used this as your driver for the second set of coils?

It's possible, and systems like this were used to step up voltage in 
early radio transmitters (as the transmitter used by Marconi 100 years
ago to transmit telegraphy across the Atlantic).
For a conventional Tesla coil, there are interesting possibilities, 
as to use a first coil operating at high coupling coefficient (0.6,
for high efficiency) just to step up the power supply voltage and 
charge a second primary capacitor at high voltage. The second coil 
would then operate at high impedance (more inductance, less
capacitance),
with corresponding reduced losses in the spark gap. The operating 
frequencies of the two coils could be unrelated.

Antonio Carlos M. de Queiroz