Night security light circuit

Description
This is a simple circuit which is build around a CMOS Ic 4060 and LDR. During the day time LDR has low resistance which keeps the pin 12 of the IC1 high. And also for the night LDR resistance become high and the pin 12 or IC1 is becomes low and the IC start oscillating, which indicate by the flashing of LED D3.The values of the timing components R1, R2, C4 are so selected that the out put pin3 of IC1 goes high after 8 hours. That means the high output drives the triac to switch on the lamp around 2’O clock.At morning time the LDR resistance drops and the pin 12 of IC1 goes high and stop the oscillating which makes the lamp off. Where Switch S1 is used to manually ON the lamp.The capacitor C2 prevents false triggering.

Circuit Diagram

Notes.

* Assemble the circuit on a good quality PCB or common board.

* The LDR can be general purpose LDR.

* The light sensitivity can be adjusted using the preset R6.

* The IC1 must be mounted on an IC holder.

Comments

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