Diode D 1 blocks power to the relay, and the protection circuit dissipates no power. Figure 4 With reversed input voltage, the relay switch engages, interrupting power to the system, and the LED ...

This activates the relay and the AC load connected to the NO (Normally Open) contacts of the relay turns on. This condition remains until LDR illuminates in the morning and then the lamp turns off.

Prevent arcing and extra power loss in a relay circuit by timing its switching at zero-crossing with a high-voltage GreenPAK IC.

This power-conditioning circuit for an automotive electronic control unit replaces bulky transient absorbers with an electronic switch, Q1, and an electromechanical relay with an RC timer circuit ...