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Re: Calculating Sec. Voltage
Tesla List wrote:
>
> Subscriber: greenj-at-swlogica.demon.co.uk Wed Feb 12 23:02:15 1997
> Date: Wed, 12 Feb 1997 12:19:00 -0500
> From: Julian Green <greenj-at-swlogica.demon.co.uk>
> To: tesla-at-pupman-dot-com
> Subject: Re: Calculating Sec. Voltage
>
> OK, we cant measure the output voltage of a TC, or calculate it as
> there are too many variables, but we can measure the voltage of the
> first turns of secondary from the earthy end. The voltage rise up the
> coil may not be linear, but be proportional to the standing wave in the
> resonator. Taking the voltage of the first few turns would make a good
> start.
>
> Julian Green
Julian,
Nice theorizing! Alas, even this is complicated by the fact that the
voltage distribution as we go up the coil will only be sinusoidal if
there's no topload capacitance (no discharge terminal) AND the top of
the secondary "looks" like an open circuit (no breakout). But this is a
catch-22: no discharge terminal almost certainly guarantees that we'll
get breakout. Adding a discharge terminal adds lumped capacitance, which
results in a complex non-sinusoidal voltage distribution that's
somewhere between being linear (pure lumped LC) and sinusoidal (1/4 wave
transmission line).
However, if you added a very large top terminal, with a capacitance that
was _much_ bigger than the secondary self-C, you would get a "mostly"
linear voltage distribution. Under these conditions, measuring the
per-turn voltage rise might be a valid predictor of Vmax without
breakout.
Safe coilin' to you, Julian!
-- Bert H --