Procedure
In the figure below we show how to make the connections of the elements of the circuit for the measurement.
We can either connect the milliammeter to the appropriate current range in series with the continuous supply of the amplifier as we use the resistor and measure the voltage on it.
We initially measured the voltage on the resistor with no input signal to measure the power consumed without signal (rest). See INS122,
Then, we apply a 1 kHz signal to the amplifier input and open the entire volume.
Measure the current in the amplifier or measure the voltage across the resistor.
By multiplying the current by the supply voltage, we have the effective consumption and therefore the RMS power can be obtained by subtracting the power at rest.
By multiplying the measured voltage on the resistor by its resistance we have the power consumed. Likewise, by subtracting the power at rest we have the output RMS power.
