Re: Tesla Coil Operation - was "Harmonics"

Tesla List wrote:
> Original Poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> John H. Couture wrote:
> >   The Tesla coil operation has no mechanical or other electrical analogy.
> It has. Two pendulums (penduli?) with identical lengths (same resonant
> frequency) and different weights (different impedance levels) are
> coupled in a way that produces a high swing in the lighter pendulum
> when the swing in the heavier pendulum is small (a transformer
> with high turns ratio). This may be a light inclinated bar connected
> to their strings (use a fixed width font to see the ASCII drawing):
>        ==+===+==
>          |   |
>          |\  |
>          | \ |
>          |  \|
>          |   |
>          o   O
> If you set the heavier pendulum in motion ("O", the "primary"), it
> will make the lighter pendulum ("o", the "secondary") swing with
> increasing amplitude, as its swing amplitude decays. Eventually
> only the lighter pendulum is oscillating, and the process reverts.
> The result is the same beating oscillations observed in Tesla coils.
> I tried this experiment, and it works perfectly.
> No sparks, of course ;)
> Antonio Carlos M. de Queiroz


	The demonstration you describe does indeed happen.  However, if the
coupling between the two pendula(?????) is sufficently high (probably
adjustable by adding mass to the gar which joins them), the oscillations
of both pendulums will consistent of two different frequencies at the
same time, and the beating is indeed real.  You can demonstrate the
"beating" in an over-coupled tuned circuit (kQ>1) by drawing the
waveform which is produced by adding two frequencies of the appropriate
value.  The primary and secondary waveforms of the Tesla coil BEFORE
quenching show this phenomenon, which is quite pronounced for large
values of coupline.  Once the gap has extinguished, the secondary
continues to "ring" at its resonant frequency.