Joined Mar 24, 2008
Are you wanting to measure total wattage of the circuit, or output power?

For total wattage of the circuit you measure the current, then the power supply voltage.

P = V * I

Thread Starter


Joined Sep 6, 2011
It will be helpful if both.
I know the formula of the Power, but what I am after is to where in the circuit and how will I connect my WATTMETER?
Because I tried connecting and simulating it on the output part and it reads ---.--uW.


Joined Mar 6, 2009
You would interpose the wattmeter between the amplifier output and a purely resistive dummy load which replaces the speaker - it might be 8Ω. You would have to inject a suitable signal at the amplifier input. The input signal level (say using a 1kHz pure sine wave source) would be increased until the power output was as expected, but not at a level where unacceptable distortion of the amplified version of the input signal is observed at the load. So you would need to assess the output signal quality (harmonic distortion) to make this a genuine test of output power performance.


Joined Nov 30, 2010
You also need to be sure your wattmeter works properly at the frequency you are measuring. A Kill-A-Watt meter for appliances will not measure (most) audio frequencies.