1, AC current is limited by R 1, rectified by D 1 and charged by c. When the trigger voltage of DIAC is reached, DIAC is turned on, LED is turned on, the stored electric energy of C is released, the voltage across C is reduced, DIAC is turned off, LED is turned off, C is charged, and so on, and the circuit flashes.

2. it is no problem to add DC D 1 and remove it, but there is no finite flow after removing R 1. The power supply is directly added to the flash circuit, and the current can completely meet the continuous lighting of LED, and C also loses its function.

3. Direct current is directly applied to both ends of the original circuit of 220V. If the flashing speed is too slow, you can appropriately lower r 1(d 1 is optional).