This simple circuit indicates the amount of power that goes to a loudspeaker. The dual-color LED shows green at an applied power level of about 1 watt. At 1.5 watts it glows orange and above 3 watts ...

An analog VU (volume unit) meter is a splendid moving-coil measuring instrument. It is a passive electromechanical device displaying a representation of the signal level in an audio equipment. Even ...