a small cathode-ray tube having a fluorescent screen on which the pattern varies with the voltage applied to the grid: used chiefly in radio receivers to indicate accuracy of tuning.
a solid-state device that converts light into electrical energy by producing a voltage, as in a photovoltaic cell, or uses light to regulate the flow of current, as in a photoconductive cell: used in automatic control systems for doors, lighting, etc.
photoelectric cell n. An electronic device having an electrical output that varies in response to incident radiation, especially to visible light. Also called electric eye.
[i-lek-tron-rey] 