Straight out of "Engineers Mini Notebook- OpAmps" and from the mind of radio shack's resident guru F. Mims III, I bring you this fun little circuit. Those AC sources on the left represent input to the circuit from an audio device. I use a Y-stereo splitter to see the lights and still hear the music :°) It's a fun one to build and even more entertaining to watch! It employs a pair of dual OpAmps configured as active filters so that each different colored LED' intensity is proportional to the frequency band to which it is assigned. Shown here is a basic low, mid, high arrangement, but i'm sure the circuit can be modified to use whatever band widths you see fit. Don't ya just love being nerdy? I do..
P.S. The set of LEDs is on the bottom right corner. I know, it seems a little slow but the real thing is much more reactive..
