Light-Operated Streetlight (10)

Published:2011/7/8 5:41:00 Author:Sue | Keyword: Light-Operated, Streetlight | From:SeekIC

In the daytime, the photeresistor RG will have a low resistance value because of the light. IC's pin 2's and pin 6's voltages arehigher than 2Vcc/3. IC's pin 3 will output low level, which will make the relay K connected. Its normally open contactors K1 and K2 are both disconnected and the illumination EL is not illuminated. When it is dark, RG will have a larger resistance value because of lack of light. IC's pin 2's and pin 6's voltages will become lower. When the voltage is lower than Vcc/3, IC's pin 3's low level will become high level which will make the relay K released. Its normally closed contactors K1 ,K2 are both connected. The illumination EL is illuminated.



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