On Sun, 31 Dec 2006 16:28:12 GMT, (Doug Miller)
wrote:

How about closing an AC circuit through a capacitor?
Would you agree that the AC 'passes' through the capacitor
even though the electrons do not?

In a sense, anyway -- but I think we're splitting hairs. Certainly if you
apply an alternating current to one side of a capacitor, you get an
alternating current out of the other side too.

The hair splitting is in how the phenomenon is described or measured,
and it's easily confused by the base terms. In other words, the base
term is "Alternating Current" which should describe voltage of a
certain frequency.

In the capacitor scenario, the confusion arises because we tend to
think of DC and its "flow of electrons." Obviously that flow must come
to a stop at an open circuit, i.e. the capacitor. However, in AC,
where the electrons only move a relatively short distance (and
depending on frequency) before switching direction, the "effect" of
electron flow is seen as being across the capacitor.

That "flow" is measured as current, which leads to the precept that AC
flows through a capacitor and DC is blocked by it. In truth, however,
although you can measure the current flow, and work is actually done,
the electrons don't actually cross the capacitor.

--
LRod

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Shamelessly whoring my website since 1999

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