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Wire length,resonance, and Q (fwd)
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From: Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Monday, May 25, 1998 11:28 PM
To: Tesla List
Subject: Re: Wire length,resonance, and Q (fwd)
Hi Bart,
> From: Barton B. Anderson [SMTP:mopar-at-uswest-dot-net]
> Sent: Saturday, May 23, 1998 11:40 PM
> To: Tesla List
> Subject: Re: Wire length,resonance, and Q (fwd)
>
> Hi Malcolm (btw - thanks for the great replys! - love this stuff!),
<snip>
> Your probably correct here as the Medhurst's formula considers
geometric dimensions
> where the standard 1/4 wave formula does not. This particular consideration adds
> substance that only tested methods can provide.
>
> Medhurst formula: C = K * D
> C = solenoid self-capacitance in picofarads.
> K = a constant which depends on the ratio of the coil height and diameter.
> D = diameter of solenoid in centimeters.
>
> This formula takes into consideration the geometric ratio and corresponds it to a given
> K. How K was actually determined I assume is by way of emperical data. However, for the
> secondary to yield it's highest voltage potential at the toroid (regardless of top C),
> there must be a 1/4 wave *situation* occurring in the circuit, even if it is not based
> entirely on the 1/4 wave wire length *situation*. I guess what I'm contemplating is if
> the 1/4 wave length of the P-freq. would correspond to the length of the secondary
> winding if the unknown variables were taken into account with the formula? I wish I
> knew just what all those variables were. Would't Vout be optimized?
>
> Bart
Don't see why. If yu feed in a lump of energy and that energy is
mostly concentrated in Ctop at some stage then the old 0.5CV^2
applies. I loved Greg Leyh's explanation of why it *should* apply,
namely that the V^2 term is highest at the top. I think calculating
Vout based on no terminal is academic unless one runs with no Ctop
but then how well can you do if you are lacking ROC at the top?
What thinks anyone?
Malcolm