12+ 12V Ldr Relay Circuit. If you want to change the functionality of this circuit, simply. Here is the schematic for the circuit
You should keep the ldr in such a way that light from lamp l1 (connected to this circuit) will not fall on it. This light sensitive circuit can operate a relay to switch on lamps or any ac loads when it senses darkness. There are 70 suppliers who sells ldr circuit on alibaba.com, mainly located in asia.
An ldr or light dependent resistor is a resistor where the resistance decreases with the strength of the light.
12+ 12V Ldr Relay Circuit. The collector of q1(bc107) is coupled to base of q2(sl100). This change in resistance of ldr detect by a circuit. In the case of the dark sensor + relay, is it ok to use 12v as the. Since the relay has 12v trigger voltage we have used a +12v dc supply to one end of the coil and the other end to ground through a switch.