The circuit diagram of a blinking LED that can be operated from the mains supply is shown here. The working of this circuit is as follows. When mains power is switched ON the capacitor C2 charges through resistor R1 and diode D1. When the voltage across the capacitor becomes greater than 32V ( break over voltage of diac DB3) the diac conducts making the LED blinks and capacitor C1 discharges through the LED.This cycle repeats again and again .
- 230V is potentially dangerous , be very careful while handling this circuit.
- The timing of this circuit depends on resistor R1 and capacitor C1.