Re: Wheeler (Number of turns for a secondary?)

Tesla List wrote:

> It is a formula for calculating the inductance of a coil.  It is
> least for us Americans) as all the dimensions are in inches.  The result
is in
> microhenries.
> For a single layer solenoid:
> L = r^2 * N^2 / (9*r + 10*b)

This is also a translation to inches of the formula in metric units:
L = 4*pi*1e-7*pi*r*r*N*N/(b+0.9*r)

This is simply the formula for the inductance of a long coil (r<<b)
with an approximate correction factor 0.9*r added to the length b.

Antonio Carlos M. de Queiroz