Roger wrote:
Why is it the same equation? I understand your P = V(t) * I(t) to be V
and I as functions of time, but Keith to be using what ever he reads
from his voltmeter and ammeter.

There is a conspiracy to confuse you by using the same
symbol for completely different values - don't fall for
that Tar Baby.
--
73, Cecil http://www.w5dxp.com