Simplest lamp flasher circuit.

This is a very simple lamp flasher circuit that uses only three components (a capacitor, relay and one resistor) other than the lamp. The working of the circuit is very straight forward. When the power is switched ON the capacitor C1 charges through the resistor. When the voltage across the capacitor is sufficient, the relay switches ON and the lamp connected via the normally open contact of the relay glows. The relay remains energized until the capacitor discharges and then the lamp extinguishes. The charging and discharging cycle of the capacitor gives a flashing effect to the lamp.

Circuit diagram with Parts list.

Simplest lamp flasher


  • The relay L1 can be a 12V SPDT relay.
  • The lamp L2can be a 12V, 5W lamp.
  • The frequency of flashing can be varied by changing the value of C1 and R1.

Sorry, comments are closed!