Re: Tesla Coil Operation - was "Harmonics"

to: Antonio

An interesting corollary is to use a long shaft of semi-flexible material. 
Attach pendulums (sorry -- no penduli) of different mass.  As the first
pendulum in activated the pendulum of the same mass located further down
the shaft will begin to oscillate as you described.  The interesting part
is that pendulums of different mass do not oscillate (very small amplitude
if at all) which dramatically illustrates the concept of tuned circuits
while other nearby circuits of different frequency (mass in our mechanical
example) oscillate only a very small amount.

We have made this exhibit for various museums and the children are always
amazed that both nearby pendulums and pendulums of lighter mass don't start
to oscillate first.  It's a simple exhibit to fabricate and is very
instructive for anyone to use prior to the Tesla coil demonstration of
electrical resonance.


> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Tesla Coil Operation - was "Harmonics"
> Date: Sunday, January 17, 1999 6:54 AM
> 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
> 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