Re: Inductance of a conical coil

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

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

 > I see closer agreement with this correction factor. The only limitation is
 > obtaining k, which we need a measurement or one of the higher order
 > programs to resolve.

My idea was to do this only once, for a typical 45 degrees coil. But
I see now that the weak formula for the flat coil twists the results...

 > No, Wheeler's flat coil equation does not fair well. I suspect the reason
 > is due to turn-to-turn inductance is non-linear simply due to the geometry
 > of the flat spiral as opposed to a helical coil where turns are linear to a
 > far greater degree (all turns are of the same size). I believe the formula
 > is not accounting for this fact and is assuming internal coil inductance is
 > similar to that of a helical. Just a guess.

The field is more irregular in the case of a flat coil, but the formula
tries to be simple. There must be a better formula around,
specially today when small flat coils, even inside integrated circuits,
are present in virtually all communication equipments.

Antonio Carlos M. de Queiroz