Light Sensor and Darkness detector circuit using LDR and Transistor

Light Sensor / Darkness detector circuit on breadboard using LDR and a transistor. This circuit can be used to automatically control and turn on-off lights or any loads depending on the brightness of ambient light, by adding a relay at the output. The sensitivity a.k.a the brightness at which the circuit switches on the load can also be controlled by using a potentiometer. Watch the video above for detailed step by step instructions on how to build this circuit. 

Components Required:

1. 1 LDR (Light Dependent Resistor or Photo-resistor) 
2. 1 npn Transistor (I used BC547)
3. Resistors: 470R, 1K (For Light Sensor), 47K (For Dark Sensor)
4. Potentiometer (Only if you need adjustable sensitivity): 10K (For Light Sensor), 100K (For Dark Sensor)
5. Breadboard
6. Power Supply: (3-12)V
7. Few Breadboard connectors

Circuit Diagram:

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