Re: Inductance of a conical coil

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

Original poster: "Barton B. Anderson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <classictesla-at-netzero-dot-com>

Hi Antonio,

Tesla list wrote:

>Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
>
>A flat coil with rmin=0.1 m, rmax=0.4 m, 40 turns.
>Splitting the coil in two:
>rmin1=0.1 m, rmax2=0.2 m, rmin2=0.2 m, rmax2=0.3 m, n1=n2=20 turns.
>I get there results:
>               Inca     Fantc
>L1           0.1541    0.1517
>L2           0.3175    0.3148
>M            0.0961    0.0961
>L            0.6631    0.6595
>L1+L2+2*M    0.6638    0.6587
>
>Not bad. I will make a flat coil to see what Nature says.

Nature will know, but how accurate is your meter and can it read that low?

I was thinking about the flat spiral case. Have you considered looking at a 
mutlilayer formula? By "concept", the flat spiral is similar to a 
multilayer coil, except the length of the coil doesn't really play a 
significant role since the length becomes the wire size. I expect 
multilayer formula's are derivitives of Wheeler, so maybe just stripping 
down of what is not needed.

Take care,
Bart