Re: flat coil ?

["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 4/25/02 8:48:01 PM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:



>
> Original poster: "Chris Swinson by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <exxos-at-cps-games.co.uk>
>
> Hi Bart,Paul, all,
>
> I did some calcs on tube wound coils and it looks like inductance is more
> with a flat coil ? capacitance looks about the same to the results below.
> Frequency is about 220khz with tube wound coil.  Would I expect the flat
> coil to work better than a tube wound coil ?
>
> Chris
>


Hi Chris,
         Yes, for a given length of wire, a spiral coil has more inductance
than a helical coil, until you get into some pretty severe space-wound coils.
BTW, the maximum achieveable inductance (for a fixed length of wire) of a
spiral occurs when r(outer)=(pi-1)*r(inner). That is, you can get more
inductance for a fixed amount of wire, if you wind an open-centered coil 
instead of starting all the way in the center. 

Matt D.
G5-#12
<http://www.thegeekgroup-dot-org>http://www.thegeekgroup-dot-org