Figure shows signs of light controlled automatic flashing lights circuit. The circuit consists of step-down the entire Li-circuit, the light control switch, 555 multivibrator and so on. Buck rectifier circuit which provides DC voltage for the entire circuit.
BG circuit for the 3DU type phototransistor. By the light during the day after, BG smaller terminal voltage (<1.6V), the power tube TWH8778 potential due to low foot end corresponding multivibrator does not work, SCR SCR is not conducting, ZD light does not shine. Tian An, the photodiodes of the resistance increases, and even open, TWH8778 potential for feet high (> 1.6V) and conduction, the power supply circuit 555 connected to the oscillator for oscillation. The oscillation frequency f = 1.44 / (R2 2R3) C2, corresponding to the frequency of the icon parameter is about 1Hz. The output of the oscillator pulse current limiting resistor R4 by the post-trigger SCR turns on, flashing light bulbs ZD to remind pedestrians to walk attention.