Light-operated Automatic Scintillating Road Signal Lamp Circuit Composed of 555

Published:2011/8/25 7:48:00 Author:Sue | Keyword: Light-operated, Automatic Scintillating, Road Signal Lamp | From:SeekIC

The picture shows the light-operated scintillating road signal lamp circuit. The circuit consists of voltage reduction and rectification circuit, light-operated switch, 555 multivibrator, among which the voltage reduction and rectification circuit provides the whole circuit with direct current voltage. In the circuit, BG is 3DU-type photosensitive triode. In the daytime, when there is light, BG's terminal voltage is small(1.6v) which will make power tube TWH8778 disconnected because of pin 5's low level. Then multivibrator doesn't work correspondingly and silicon controlled rectifier SCR is not connected. The lamp ZD is not illuminated. When it is dark, the photosensitive tube's inner resistance value becomes higher and even broken. TWH8778 is connected because of pin 5's high level(1.6V) which will make 555 oscillator begin to work because of the connection of the power circuit.



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