Photoresistors, also known as light dependent resistors (LDR), are light sensitive devices most often used to indicate the presence or absence of light, or to measure the light intensity.

How does a LDR sensor work?

Working Principle of LDR. … These devices depend on the light, when light falls on the LDR then the resistance decreases, and increases in the dark. When a LDR is kept in the dark place, its resistance is high and, when the LDR is kept in the light its resistance will decrease.

What is the light dependent resistor and how does it work?

A Light Dependent Resistor (LDR) is also called a photoresistor or a cadmium sulfide (CdS) cell. … It is basically a photocell that works on the principle of photoconductivity. The passive component is basically a resistor whose resistance value decreases when the intensity of light decreases.