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Re: Keeping up with the theory (was is Corum and Corumforbidden topic?)
Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
I think there are two issues here:
On 6 May 2002, at 7:08, Tesla list wrote:
> Original poster: "Ray von Postel by way of Terry Fritz
> Thanks for the information on the availability of programs.....even expensive
> ones. My
> comments were based on the method of computation using empirical equations
> than those that are general in nature. Why use approximations if there are
> better methods?
> 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
> the case,
> then why bother with Wheeler et al?
First there is a scientific approach to model resonators etc. as
exactly as present techniques will allow. This will probably lead to
optimizations for building a coil specified requirements and possibly
new phenomena to be investigated as precision in the result improves.
Secondly, there is a dirty quick and simple approach to designing
coil which *will work* even if not optimally. Approximations such as
Wheeler and Medhurst are ideal for back-of-the-envelope calcs to get
well within the ballpark. I frequently use these methods with 100%
success. Suppose I have a friend over who wants to see a coil going -
or I wish to show him/her something about a running coil. I can pull
a resonator off the shelf, pull a primary out of the rafters, do some
quick calcs and have a running coil for some particular power level
in a matter of minutes.
> No one, so far, has convinced me that a project to come up with a
> 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
> 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 think there are a number of programs around that would fulfil that
need. I don't personally use them. A calculator is sufficient for me.
Regarding an accurate Cself for the resonator, Medhurst does a pretty
good job but in the end, take sno account of the terminal one usually
places on top of the resonator. Likewise, a formula for the bare
capacitance of a particular terminal takes no account of the mutual
interaction with the resonator below it.
> This seems to be getting a bit far from coiling, I would be glad to continue
> discussion off list.
Don't agree - unless I've misunderstood.