12-V Light Organ

Many people would like to build a light organ but are scared off by the dangerous mains voltage. A direct electrical connection to the amplifier should also be avoided. The light organ circuit presented here has been developed for 12-V halogen lamps and is controlled by sound waves. All you need is a triac, a condenser microphone and a few other components.The electret condenser microphone needs a supply voltage, since it has a build-in amplifier. A supplementary transistor stage amplifies the microphone signal and feeds it to the gate of the triac.