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 ...

Jordan is an editor for Android Police and a technology enthusiast. He writes frequently, both professionally and as a hobby, loving the process of putting pen to paper... or fingers to a keyboard.

This circuit senses AC audio voltage supplied to the car-radio loudspeakers and displays it as power using a LED bar graph, achieving at the same time an attractive visual effect. It is designed to ...