Re: Wheeler (Number of turns for a secondary?)
In a message dated 1/7/99 3:19:01 AM Mountain Standard Time, tesla-at-pupman-dot-com
> > 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
That is pretty much the classical formula for long coils, but most TC's
are not that geometry.
If one wants to use metric, The wheeler formula can be altered quite
easily. In fact you can simply put in the r and b values in centimeters and
just divide the whole expression by 2.54.
L = r^2*N^2/(2.54*(9*r + 10*b)), where now the dimensions are in centimeters.
The inductance is still in microhenries.
Mike(slowly converting to metric, inch by inch )