Cecil Moore wrote:
wrote:
In a loading coil with very small distributed capaciatnce to the
outside world compared to termination impedance, current has to be
equal. Phase shift in current at each end has to be nearly zero.
That is a false statement and is at the root of the misconceptions.
Standing wave current does not have to be equal.
I assume you are meaning that the RMS current at one physical point
must not equal the RMS current at some other point.
I have shown how
current at the bottom of the coil can be zero while the current
at the top of the coil is one amp. Do you think the coil is sucking
that one amp sideways from somewhere else through its distributed
capacitance?
(snip)
Of course that is what is happening. It is what happens in any
transmission line like device. There is a standing voltage wave,
also, and that produces displacement current through any capacitance,
just as the antenna does.
Aren't you claiming that the coil has transmission line like
properties, in that it takes time for a wave to pass through it?
Any such device needs two mechanisms for storing energy, one magnetic
(inductive) and one electrical (capacitive). Even free space has
both. If you eliminate either mechanism (or make one of them
insignificant, as would happen to the capacitance if the inductor
approaches zero size), you lose the transmission line like properties
as the dominant mechanism.