Sound actuated light switch

A sound actuated switch including a microphone coupled via an audio amplifier to a reset circuit. When a sound of sufficient intensity is received by the microphone a reset signal is supplied to the counter portion of an oscillator and counter circuit. The counter then begins counting oscillations and produces an "on" control signal until a predetermined count is reached, at which time an "off" control signal is produced. The control signal is supplied to the gate of a switching triac in a switch circuit. The presence of the on control signal causes the switching triac to electrically connect an AC power source to a load, typically a light. A simple, high efficiency DC power supply is also disclosed.