Certainly there is such a thing as RMS power. It just isn't useful for
anything. The definitions I used aren't arbitrary at all, but widely
accepted and agreed upon. It's true that some amateurs and consumer
audio marketers have chosen not to use the accepted definitions, but
their inventions shouldn't be given equal weight to ones which have been
used for centuries and are universally accepted by the math, physics,
and engineering communities.

What's the problem with current flowing from plus to minus? I believe it
was Ben Franklin who realized that there are two polarities of charge,
and arbitrarily called one plus and one minus. If he had made the other
choice, positive or negative charge would indeed flow the other way.

I've been through technical school, where current was considered to flow
from minus to plus, and engineering school, where the opposite
definition was used. You can use either method and arrive at the correct
answer, but you end up with quite a few more minus signs with the
minus-to-plus convention. Since engineering is highly mathematical, the
plus-to-minus convention makes sense for engineering because of the
somewhat simpler equations that result.

I've always thought that tech schools used the minus-to-plus convention
because it made it easier for students to get an intuitive feel for how
a vacuum tube operates. (It's hard to imagine positive charge leaving
the plate and condensing on the hot cathode!) Now that fire-fets are
(like some of us) largely relics of the past, and the importance of good
communication between technicians and engineers is recognized, I'd be
surprised if the minus-to-plus convention is still being taught even in
tech schools -- if anyone has any recent information about this, I'd be
interested to know.

Roy Lewallen, W7EL

Bill Turner wrote:
On Fri, 08 Oct 2004 11:08:35 -0700, Roy Lewallen wrote:


Did you read what I wrote?


__________________________________________________ _______

Yes, of course.

I'm becoming convinced this is more a question of semantics or of
somebody's arbitrary definition than one of actual fact.

My real disagreement is with the statement "There is no such thing as
RMS power". The rest of the arguments here I have no real quarrel with.
As far as I can tell, all the math presented here is correct, with the
exception of the fellow who the wrong factor when converting RMS voltage
to peak power.

To each his own.

Now, what about that current flow from plus to minus? :-)

--
Bill W6WRT