Photoelectric switches, also called photocells, are sensors that detect the presence of light. When exposed to ambient light or darkness, photocell solutions are able to switch lighting loads connected to lighting controllers.
Photocells are most commonly used to provide dusk-to-dawn lighting control for security, task, or landscape lighting. Many switches also offer delay action, which eliminates loads switching on or off due to brief changes in ambient light conditions, like car headlights or lightning.
The automatic switching nature of the photocell contributes significantly to energy savings, as lights can be turned on or off automatically, only when absolutely needed.