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0.5*C*V*V vaild? (Was Output Voltages and Voltage/Length)


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From:  Antonio Carlos M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
Sent:  Sunday, February 08, 1998 11:20 PM
To:  Tesla List
Subject:  Re: 0.5*C*V*V vaild?  (Was Output Voltages and Voltage/Length)

Mark S. Rzeszotarski wrote:

>         And yes, this means that the LED's are brightest at the base of the
> coil, and dim or off at the top of the coil, indicating maximum current at
> the base and minimum current at the top.  The LED's are connected
> back-to-back and are current monitoring devices. 

Ok. It is an interesting measurement method. In some old books it is possible
to find descriptions of devices that do the same using corona. The system
is a coil with one or two grounded wires in parallel at a short distance. In
the dark it is possible to see RF corona between the wires and the coil,
with intensity proportional to the coil voltage.

> One can demonstrate half wave and higher harmonic standing
> waves with H/D ratios as low as 1:1, although it is better seen on the 3:1
> or 4:1 coils.

This demonstration would be a proof that the antenna theory is applicable
to Tesla coils, that are in this case really showing distributed effects.
Do you have data about these measurements? In particular, I would like to
see if the frequency of the half wave resonance is consistent with the
primary 1/4 wave resonance frequency (about twice it), with and without a top
terminal (toroid) added. The lumped model predicts just -one- resonance
in any case. For usual sizes and frequencies used in these coils, I would
expect secondary resonances only at frequencies much higher than the first,
with the lumped model being good enough in this case.

Antonio Carlos M. de Queiroz
mailto:acmq-at-compuland-dot-com.br
http://www.coe.ufrj.br/~acmq