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Re: AC electricity



Tim O'Donnell wrote:

I know that AC delivers energy - that is obvious.
But I still have trouble understanding how this is possible
since half the time the potential is positve and the other
have it is negative. It seems they should cancel out.
I know and can do the rms (root mean squared - although
shouldn't it be squared mean root) for figuring out various
quantities, but I still don't think I have a basic
understanding on "how" it really works.

Several people responded. Note that P=I^2*R, is positive,
even when I is negative.

Suppose two equal constant currents flow through a wire
in opposite directions. Each current would contributes to P
but a DC meter (d'Arsenval galvanometer with a shunt),
connected in series with the wire, would show I=0.

Is it possible to have two equal constant currents flowing
through a wire (or a lamp) in the opposite directions at
the same time? How?
Ludwik Kowalski