Re: Medhurst problem

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Medhurst problem
From: Tesla List <tesla-at-stic-dot-net>
Date: Fri, 14 Nov 1997 01:32:48 -0600
Approved: tesla-at-stic-dot-net

From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Thursday, November 13, 1997 2:08 PM
To: 	Tesla List
Subject: 	Re: Medhurst problem

On Thursday, November 13, 1997 12:47 PM Tristan Stewart
[SMTP:tesla_coiler-at-hotmail-dot-com] wrote;

> Tesla List readers,
> 
>  I was thinking about the Medhurst formula and I problem came to mind. 
> All the formulas I have seen deal with only the width and length of a 
> coil. What if a coil was space wound or used insulated wire for its 
> secondary windings? This should have a lower capacitance, but the 
> formula would give the same value. And also, what of the diameter of the 
> wire? Does it not have any effect? My first thought would be that a 
> smaller guage wire with more turns would have a higher capacitance 
> value. Well, I havent given it a second thought yet. Could someone set 
> the records strait here?
 
Tristan, what your talking about effects the inter-turn capacitance on the 
coil and whatever value that happens to be it is in series with the next 
turn, one can quickly see that this value become insignificant across the
whole coil. For all intents and purposes one could look at a coil as a 
solid cylinder with all it's capacitance being in relation to ground.
BTW you are aware that you should be striving for the smallest possible
distributed capacitance in your secondary. The reason is that the ratio of
voltage transformation in a tesla coil IS NOT related to it's turns ration 
but instead it is related to the ration of primary to secondary capacitance
or since the reactance of the capacitance is equal to the reactance of the 
inductance at resonance one could also say that the ratio of transformation 
is related to the ratio of primary to secondary inductance. Either way the 
maximum ratio of transformation is achieved when the primary inductance is as 
small as possible and when the primary capacitance is as large as possible 
while at the same time the secondary inductance is as large as possible and 
the secondary capacitance is as small as possible.

                               Sincerely

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                           Alfred A. Skrocki
                   Alfred.Skrocki-at-CyberNetworking-dot-com
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