光电池；光电感应器；光电管an electric device that uses a stream of light. When the stream is broken it shows that sb/sth is present, and can be used to control alarms, machinery, etc.
n.
1.
〔物〕光电池;光电管
un.
1.
光电元件
n.
1.
asolid-statedevicesensitivetovaryinglevelsoflightthatisusedtogenerateorcontrolanelectriccurrent, e.g. inburglaralarms, smokedetectors, andexposuremeters