Re: Quarter Wavelength Frequency

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Paul,

It did seem like he was saying there would be two resonances.  The "1/4
wave" resonance (if we choose to use this name) must then refer to what
resembles a standing wave in the distribution of currents and voltages along
the length of the coil.  If the voltage profile (unloaded) is close to
sinusoidal, then the voltage gradient must look like the current profile
(the greatest turn to turn stress at the bottom).

Could you explain why the turn to turn stresses seem to go up and often
results in racing arcs at about the 2/3 point up from the bottom when the
coil is run out of tune?

Gerry R


 > Original poster: Paul Nicholson <paul-at-abelian.demon.co.uk>
 >
 > Gerry Reynolds wrote:
 >
 >  > There are a lot of experience folks on this list that have
 >  > said that 1/4 wave resonance does not come into play and
 >  > the resonance is determined by the effective LC parameters
 >  > of the coil (or coil and top load combo).
 >
 > There's no complaint with the '1/4 wave resonance' bit, it's
 > a perfectly good name for the fundamental resonance of a
 > structure clamped at one end and free at the other.  It is
 > equivalent to 'LC' resonance.
 >
 > Our point to Jared is that the frequency of this resonance
 > is set by the self and mutual reactances of the structure in
 > question, and not by the properties of the materials that
 > went into its construction.  To use a mechanical analogy,
 > one wouldn't expect a tuning fork to keep the same frequency
 > after it had been hammered and worked into a different shape.
 > Jared I think is saying that the tuning fork will ring not just
 > with its new frequency but also its old one too.
 > --
 > Paul Nicholson
 > --
 >
 >