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Em 10/06/2020 14:41, Tedd Dillard escreveu:
I seem to remember some post in the past about the differences in
capacitance of various designs. I have not been able to search the old post
very well so have not found them. But what I remember is that there is some
relation to the surface area of the conductive material to the surrounding
air relating to the electric field.
I have wondered what part of the total capacitance of the toriod does the
hole play. What is the difference of a toroid to a hockey puck? Seems to me
the inside of the hole is not exposed to any field differential.
Teddy
The outer shape is what determines the capacitance. The hole really
doesn't make much difference. There is a rule about distributed
capacitances that says the bodies with similar maximum diameters have
similar capacitances. The worst possible case are a sphere and a
straight wire. A sphere has 55.5 pF per meter of diameter. A straight
wire has about 11 pF per meter. Any other shapes compare better.