How is audio power measured?
Power = Voltage squared divided by Resistance.
With a constant sine wave input, you measure 10 volts AC on the speaker output of the amplifier. Since you know the resistance (5 ohms) and the voltage (10 volts), you can calculate the power: Power = (10 times 10) divided by 5 = 100/5 = 20 watts.
How does a VU meter work?
A volume unit or “VU” meter is a basic volt meter that takes a simple average of the signal and displays it with an attack and release time of around 300 ms. The slower attack time allows the faster transients to get by before it registers the signal and gives a reading.
What is a VU meter amp?
A VU-meter is a very common instrument usually installed on audio Hi-Fi amplifiers and is used to show the instantaneous power provided to the speakers. It is usually connected at the output of the amplifier, in parallel with the speaker.