Amp Power Measurement

[Magnus Danielson]

From: "Tom Priore" <tpp109 at psu.edu>
Subject: Amp Power Measurement
Date: Tue, 12 Sep 2000 01:03:51 -0400

Hi!

> I’ve been asked to find the actual RMS power for an amplifier. Is it as
> simple as pumping a test signal though it and measuring the voltage drop
> across a speaker with a know ohmage, then use the P=V^2/R?
> I have a feeling this wont work. Any insight would be appreciated.

Traditionally you set up a bunch of resistors on a cooling tunnel setup and
wire them up for the resistance of interest (say 4 or 8 ohms). Then, you crank
up your amplifier with a sine until you start to run into clipping, just at the
limit. Now, use an RMS meter to measure the voltage and then use the power
formula. Naturally you would have to have measured the resistance with some
precission or else you don't know where you are.

Rather straigth forward I'd say.

Cheers,
Magnus