- photocell
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/foh"toh sel'/, n. Electronics.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. Also called electric eye, photoelectric cell.[1890-95; PHOTO- + CELL1]
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Solid-state device with a photosensitive cathode that emits electrons when illuminated and an anode for collecting the emitted electrons.Illumination excites electrons, which are attracted to the anode, producing current proportional to the intensity of the illumination. In a photovoltaic cell, light is used to produce voltage. In a photoconductive cell, light is used to regulate the flow of current. Photocells are used in control systems, where interrupting a beam of light opens a circuit, actuating a relay that supplies power to a mechanism to bring about a desired operation, such as opening a door or setting off a burglar alarm. Photocells are also used in photometry and spectroscopy.* * *
Universalium. 2010.
