Definitions

1. noun

A light-sensitive device, especially a small semiconductor device that converts light into an electric current.

“The security system uses a photocell to detect when someone enters the room.”

2. noun

A device that controls the amount of light reaching a lens, especially by adjusting the size of an aperture.

“The camera’s photocell helps to ensure that the image is properly exposed.”

3. noun

A device that converts light into an electric current, used in applications such as automatic door openers and burglar alarms.

“The automatic door opener uses a photocell to detect when the door is opened or closed.”