# Re: Tesla Coil Operation - was "Harmonics"

```Good analogy. It seems there are always analogies for systems and it helps
to understand how they work. So is the angle of the coupling bar related to
the coupling coefficient or should it be softer such as a spring?
Dave
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Sunday, January 17, 1999 3:45 PM
Subject: Re: Tesla Coil Operation - was "Harmonics"

>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
>
>
>

```