Re: Resonant Frequency

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 2/25/02 12:52:47 AM Eastern Standard Time, tesla-at-pupman-dot-com
writes:



>
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Goinbonkers-at-aol-dot-com>
>
> Yes,   I checked a wide variety of coil diameters and wire gauges, and it
> always came out the same.   I am not saying there's any magic to it, but who
> knows?  Tesla seemed to like low aspect ratio coils - at least for the
> secondaries of his magnifiers. 
> Mike 



As has been mentioned several times before, the maximum inductance obtainable
for a given length of wire in a solenoid coil occurs when the radius r=10h/9
where h is the height (length) of the coil, or h/d=0.45. If one is using a
Tesla coil for some purpose other than making big sparks to impress the Locals,
this would be a conveniently compact ratio. For a pancake coil, it can be shown
that maximum inductance for a fixed length of wire occurs when ri/ro=7/15. 

Matt D.