What Is A Photocell and How Does It Work?

A photocell is a device that can automatically turn an LED light on or off based on the amount of ambient light available. It is particularly useful for outdoor area lighting.

Photocells are variable resistors that adjust the resistance in an electrical circuit based on the level of light present in their mounted location. To function properly, they need to be placed in exposed areas where they can receive sufficient light. Photocells, also known as photo controls, come in various shapes and sizes and can be integrated into a luminaire or added as an accessory, depending on the specific light fixture.

In some cases, it is possible to bypass a photocell when needed. Bypassing the photocell allows the luminaire to remain continuously on or be controlled by an existing switch or timer. The method of bypassing depends on the type of photocell and how it is installed in the fixture. Common bypass options include using a shorting cap, a slide or DIP switch, or disconnecting the wiring of the photocell. To ensure safety, it is important to consult the user's manual of the light fixture to determine which option(s) are applicable and how to implement them correctly. Always exercise caution and turn off the power supply before working on any wiring.