# Wire length,resonance, and Q (fwd)

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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!),

Tesla List wrote:

> ---------- Forwarded message ----------
> Date: Mon, 25 May 1998 09:13:02 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Wire length,resonance, and Q (fwd)
>
> HI Bart,
>
> > Date: Fri, 22 May 1998 04:50:06 -0500
> > From: "Barton B. Anderson" <mopar-at-uswest-dot-net>
> > To: Tesla List <tesla-at-pupman-dot-com>
> > Subject: Re: Wire length,resonance, and Q (fwd)
> <snip>
> You can do *much* better by using Medhurst's Cself and Wheeler's
> Lself.

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

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