> Diodes and other active components have qualities beyond
resistance (and
> capacitance and inductance).  Ohm's Law doesn't address such
things -- but
> they do result in an "effective resistance" under a given set
of conditions
> that can be characterized by Ohm's Law.  Also, no device
"obeys" Ohm's Law
> -- it's the relationship between I and E and R that obey...I
really think
> you're barking up the wrong tree here.

isn't that Old MacDonald's Law or something ...

Ol' MacDonald had an Ohm,
E, I, E, I, R.
and with that Ohm, he had some Amps,
E, I, E, I, R.
with an Amp-amp here, and an Amp-amp there,
here an Amp, there an Amp, everywhere an Amp-amp,
Ol' MacDonald had an Ohm,
E, I, E, I, R.

:)

or was it the Cowboy's Guide to Electricity ...

Oh, give me an Ohm,
Where resistance can roam,
Where the Amps and electrons can play,
Where the Laws are succinct,
And the short-circuits stink,
And the current can flow through the day!