Light Dependent Resistors (LDRs), also known as photoresistors, are passive components that change their resistance based on the amount of light they are exposed to. These components are commonly used in light-sensitive applications such as automatic lighting, alarm systems, and light meters. LDRs are highly responsive to changes in ambient light levels, making them ideal for automation and sensing applications.

As the amount of light increases, the resistance of the LDR decreases, allowing it to act as a simple and effective light sensor. For projects involving light detection, LDRs offer a low-cost, reliable solution for controlling circuits based on environmental lighting conditions.