ABSTRACT This is a project on clap switch on / off any electrical circuit by the sound of the clap. The clap operated circuit is a circuit which operates by clapping from a remote pond. When a person claps one, the first output of the circuit is turned on. If another one will cause to energize the third output. The basic idea of clap switch is that the electric microphone picks up the sound of claps, cough and sound of that book knocked off the table. It produces a small electrical signal which is amplified by the succession transistor stage. Two transistors cross connected as a bustle multivibrator change stage of each signal. One of these transistor drives the aver transistor which control a lamp basically this is a sound operated switch. For example, fan, fluorescent light TV and other applications can be switched on or off by clapping.