Automatic Lamp Control with Light Sensitive Switch

The circuit above is an automatic switch which functions in absence of light. The IC 4060 works as an oscillator and the generated signal is applied to the base of T4 transistor. Phototransistor T3 is in conduction by existance of light and it keeps the T5 transistor’s base at ground potential.

When no light reachs the phototransistor, it gets in insulation. T3 reachs positive potential through 22kohm. T4 and T5 both gets in conductance. The oscillator signal reachs the optic coupler and lamp(s) shines.

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Thank you.

This entry was posted on Thursday, February 7th, 2008 at 10:16 am and is filed under Electronic Control, Lighting. You can follow any responses to this entry through the RSS 2.0 feed.