LDR 5MM

This LDR 5mm changes resistance with the change in the ambient light exposure on the surface of the sensor. LDR (Light Dependent Resistor) is a type of photocell which finds excellent use in light sensing device application, whether it is automatic outdoor light ON/OFF switch or Indoor automatic light switch.
The LDR 5mm sensor works best in both Light and dark regions. Light-dependent resistors or photoresistors are a staple of electronics. If you need a way to sense the level of ambient light then there is no easier way to do it. As the light on the sensor increases then the resistance across the two leads decreases.
Two Cadmium Sulphide (CDs) PhotoConductive Cells with spectral responses similar to that of the human eye. Cell resistance falls with increasing light intensity. Applications of this product include smoke detection, Automatic lighting control, batch counting, and burglar alarm systems.