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  Light Sensor

Try the circuit for yourself. Your light-dependent resistor (LDR) is just a resistor, so you can hook it up any way you want. The only difference is that its resistance changes depending on the amount of light present. Don't forget to protect the LED with a resistor, as when the LDR's own resistance is low, the LED will be exposed to battery's current.

What can you see? When does the LED light – when you cover or uncover the LDR?

You should see the LED OFF when the LDR is covered. This is because the LDR resistance increases as light decreases and vice versa. This is due to the composition and molecular structure of the LDR internals (which we won't be going into).