I also agree.
RMS Watts is in the same silly season class as Sears and some others "Peak
Horsepower" rating of electrical motors.
Carl
KM1H
----- Original Message -----
From: "Paul Christensen" <w9ac@arrl.net>
To: <amps@contesting.com>
Sent: Saturday, March 09, 2013 5:37 PM
Subject: Re: [Amps] rms Volts, Amps and Watts
rms voltage x rms current does not give rms power. It gives mean or
average power. rms power can be calculated but has no useful value.
An insightful perspective on "RMS Power" can be found here:
http://www.eznec.com/Amateur/RMS_Power.pdf
As Steve notes, it's a meaningless term that through the years, became an
abused adjunct for the multiplication of RMS voltage and RMS current. In
1974, the U.S. Federal Trade Commission required manufacturers of stereo
audio amplifiers to state power in terms of "continuous watts." Even so,
only a few did after the new regulation went into effect.
Most of us probably remember some of the absurd power claims made mostly
by importers of Asian stereo equipment. Back in the early '70s, our own
household had a "200-watt" stereo system that if measured today probably
could not produce 5 clean watts of power per channel.
Between 1974 and now, a lot has changed with the advent of multi-channel
sound systems designed for home entertainment. For those interested, the
most recent regulatory update occurred back in 2010 and can be found in
the link below.
http://www.ftc.gov/os/2010/01/P974222amplifierrule.pdf
Paul, W9AC
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