Inductance of a multilayer coil

From:  Hollmike [SMTP:Hollmike-at-aol-dot-com]
Sent:  Friday, April 03, 1998 10:07 PM
To:  tesla-at-pupman-dot-com
Subject:  Re: Inductance of a multilayer coil

  I have one reference that give this as :

L =        0.8 * a^2 * n^2        uH
         6*a + 9*b + 10*c 

a = average radius of windings
b = length of the coil
c = difference between the outer and inner radii of the coil.
all dimensions in inches.
It states that it is accurate to 1% when the terms in the denominator are
about equal.  This is also an equation by Wheeler.  It applies as long as the
coil has a rectangular cross section.
Hope this helps,
Mike Hollingsworth