Re: R = V/I ?

[Leigh Palmer <palmer@SFU.CA>]

> If you want a black box, OK. I thought you wanted a Mixmaster stirring
> batter. A black box with current I and p.d. V, heating itself and its
> surroundings at a rate P = IV, has resistance R = V/I.
>
> If the black box has a torque-exerting shaft sticking out of it, which can
> do work when there is a current I, then R is not given by V/I unless the
> shaft is blocked so that work = 0.

All of that is consistent and not wrong, but I still fail to find merit
or utility in assigning the resistance parameter to this system. It only
pertains to one operating point.

Leigh