The work of this circuit is simple. The 400V capacitor, the bridge rectifier, the zener diode and the capacitor 100?F will form the power supply voltage which obtained approx. 9VDC from transformerless power supply design.
The integrated 555 and its annexes components generate a train of pulses applied on the triac optocoupler MOC3021 driven intermittently causing the lamp on and off continuously. The triac may be a 2N6073A or TIC226D. By changing the 100K resistor or 1?F capacitor, then the flashing time will changed too. The rectifier bridge may be four 1N4007 diodes or 400v bridge diode with 1A current. The triac should be mounted on a heat sink to prevent over heating.
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