Photocell

A light sensor that switches a system on at dusk and off at dawn automatically.

A photocell is a small light-sensing device that automatically turns a lighting system on when ambient light fades at dusk and off again when it brightens at dawn. Because it responds to actual conditions rather than a clock, it adjusts on its own to overcast days, changing seasons, and shifting sunset times. Many transformers include a built-in photocell or accept a plug-in one, and it is often paired with a timer so the lights come on at dusk but switch off at a set hour overnight to save energy. It is a simple, reliable way to ensure your property is never accidentally left dark or burning into daylight.

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