Current through coils
The capacitance of a coil is to the second "wire", that is, to the
"rest of the universe".
I forget the name of the current which flows through that capacitance.
But undoubtably, it does flow.
Apart from end-effects (as with an antenna wire) it is uniformly
distributed along a body (as with a transmission line) and is
sufficiently accurately calculable.
The whole capacitance has an equivalent capacitance which can be
connected between the ends of a coil to make a resonant circuit with
the coil isolated in space. There is a resonant frequency.
But no use can be made of the resonant frequency because as soon
anything is connected to either one or both ends of the coil the
capcitance to the rest of the world changes and the resonant frequency
shifts downwards. I could go on!
But Roy, you know all this and I mention it here for the benefit of
novices.
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Reg.
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