From: Paul
Date: Mon, 18 Feb 2002 17:34:54 +0000
Subject: Re: [TSSP] Inductance of a flat spiral coil
Malcolm Watts wrote: > As is shown computationally, h/d somewhere around 0.5 for a > closewound coil certainly does score maximum inductance if wirelength > is constant. This is mentioned in works by a number of authors, most > notably F.E.Terman. I tried this myself a number of years ago and > reached the same conclusion. Great. Mike Hollingsworth comes to a similar conclusion for the flat spiral, by differentiating Wheeler's formula. I'm trying to find the time to apply acmi to the ellipsoids and conicals, to see if there is similarly an optimum shape factor for each type, and to see if any of these can give more inductance (for a piece of wire) than the flats and helicals. I guess nobody else is trying this with acmi because nobody's wrote asking for inverse trig functions yet. > I wonder which geometry scores highest Q for a flat spiral? Hmm, that's a can of worms that I've got no stomach for right now, still having indigestion from the solenoid Q prediction issue. -- Paul Nicholson, --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.