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Re: helical cap
Malcolm, Bryan:
I have given some attention to determining the correct equation for
inductance, looking for a one-size-fits-all equation that could be
used for pancake spirals, mutlilayer solenoidals, etc. The equation
I came up with (and confirmed by multiple lab experiments) is shown
on my page at http://home.att-dot-net/~g.g.g with a full explanation.
(More complex coil forms, conicals, recursive loops, etc, do require
further interpretation to use...)
I was convinced that the 8a+11w, 9a+10h denominators used in
Wheeler's and the commonly used spiral equation were developed
haphazardly, perhaps by modifying the coefficients until the numbers
matched to an acceptable tolerance. By integrating the current
components over the lengths of a real coil, I was able to come up
with an equation which reduced to the one I show.
So far, I have had only my personal experiments for confirming
data...if this information proves useful to you, I would be grateful
to hear of your results. If your results prove it wrong, I would also
like to hear about it (science demands the truth, regardless of its
impact on entrenched opinion...)
-GGG (Jim R. Lee)
> Original Poster: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
>
> > Original Poster: bryan <bryan-at-apexrad-dot-com>
> >
> > Sorry,
> >
> > 2 2
> > a x n
> > L = ___________________
> > ________________
> > *(8a+11w)(9a+10h)
> >
> > was supposed to have a square root in the denominator. The font I was
> > using
> > didn't translate, besides it's probably a poor approximation anyway. I'm
> >
> > still trying to find the actual equation. It seems to me that somebody
> > has it
> > posted on thier web site.
> >
> > Bryan Kaufman
>
> I think it should be (r^2 * n^2)/(8a + 10h + 11r) where r = mean
> radius.
>
> ?
> Malcolm