Self-Latching Light-Activated Switch

Here is a simple Circuit Diagram of Self-Latching Light-Activated Switch Circuit. When light strikes the CDS cell it turns on the transistors which activates the relay which latches.

Self-Latching Light-Activated Switch Circuit Diagram:

Depressing SI grounds the base of the 2N3565 and the relay resets. The 250 k potentiometer adjusts the sensitivity of the circuit.