A photoresistor, also known as a Light Dependent Resistor (LDR), is a type of resistor that changes its resistance in response to changes in light intensity. It is typically made from a semiconductor material such as cadmium sulfide or lead sulfide.

The 5MM designation refers to the physical size of the photoresistor, which is 5 millimeters in diameter. This is a common size for photoresistors and is often used in electronic circuits and projects.

When light falls on the photoresistor, the resistance decreases, allowing more current to flow through the circuit. Conversely, when the light is reduced or removed, the resistance increases, reducing the flow of current.

Photoresistors are commonly used in light-sensitive circuits such as light-activated switches, light meters, and camera exposure controls. They are also used in various other applications, including security systems, outdoor lighting, and robotics.

5mm Photoresistor 5MM Light Dependent Resistor LDR Photoconductive Resistance