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Re: Keeping up with the theory (was is Corum and Corumforbidden topic?)

Original poster: "rob by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rob-at-pythonemproject-dot-com>

Tesla list wrote:
> Original poster: "Ray von Postel by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <vonpostel-at-prodigy-dot-net>
> Ed:
> Thanks for the information on the availability of programs.....even expensive
> ones.  My
> comments were based on the method of computation using empirical equations
> rather
> than those that are general in nature.  Why use approximations if there are
> better methods?
> Rob:
> Are you saying that the equations currently being used for distributed
> capacitance yield
> accurate and precise results and are based on Maxwell's equations?  If
that is
> the case,
> then why bother with Wheeler et al?

I'm losing track of what I said and when :)  I think I said that the
lumped approximations seem to be working for people.  But there are
extremely expensive programs that fully simulate a coil or systems of
coupled coils, and output multiport S-parameters.  

Now there is a free program called Fastcap.  Evidently it works on
geometric description files like Fasthenry.  I have it on my computer,
but I haven't gotten there yet.  I did make my first Fasthenry Berekely
spice model, but having PSpice, I have to figure out what to do with
it.  Maybe use SpiceOpus.  

> No one, so far, has convinced me that a project to come up with a general
> equation
> for the calculation of parasitic capacitance of a solenoid would not be worth
> while.  The
> limitation on precision and accuracy should be the ability to readily measure
> dimensions
> and not on the math.  Any such equation, set of equations, or procedure
> be usable
> by any one on the list who has a computer.  Why any one building a coil would
> want to do so is beyond me.  It seems to be a mountain that is there and  has
> not been climbed.

I agree, but then I'm biased, and most people just like experimenting. 
But there is a thrill that comes when a model turns out to work in real


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