RE: Resonance - what is it? and OLTC stuff

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

The example you cite involves only DC.  It is a fine example of
conservation of energy and Q=CV, but , no resonance was involved.

To anticipate a widely misunderstood point, resonant rise is not at all
involved in the primary/secondary circuits of a spark gap Tesla coil.
Since the energy per bang is fixed and does not add or accumulate on
successive bangs, the peak secondary voltage is governed again by
conservation of energy, not by secondary Q (not to be confused with the Q
of CV!).  

Tube and other CW coils however are continuously fed energy, so their
secondary voltage, baring corona and streamer discharge losses, IS governed
by resonant rise and secondary Q (again, inductor Quality).

Another example of resonant rise occurs when one runs a spark gap coil
without safety gaps, with the main gap set too wide, and with a tank cap
_roughly_ near the 60 Hz mains-resonant value.  If the cap is not
discharged on each half-cycle, the voltage will climb on each half-cycle.

Gary Lau
MA, USA

Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>

Jonathon -

Resonant rise can be demonstraded in several ways. The one I like is to make
a simple barn door capacitor with a small spark gap. Charge the cap when it
is closed. When you open the cap the voltage will rise and there will be a
spark across the gap. In other words with a fixed quantity of electricity
(Q) the voltage (V) and capacity (C) are related by
      Q = CV    It is obvious that if you reduce C (open the cap) the
voltage will have to rise with a fixed quantity of electricity. A large high
voltage transmitter capacitor can also be used.

This is a good classroom demostration.

John Couture