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 ...

At the end of the DI for a Simple log-scale audio meter, I promised to show how to upgrade it to work better. With these fixes, it now has near-digital performance, with faster response and smoother ...