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photocell:see photoelectric cellphotoelectric cell
device whose electrical characteristics (e.g., current, voltage, or resistance) vary when light is incident upon it. The most common type consists of two electrodes separated by a light-sensitive semiconductor material.
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photocell(foh -tŏ-sell) An electronic device that converts a light signal, or a signal in the infrared or ultraviolet, into an equivalent electrical signal. The earliest devices were photoelectric cells. These are evacuated and work by the photoelectric effect. Electrons are emitted from a photocathode when a beam of radiation falls on the surface. The electrons are attracted to a positively charged anode so that a current flows in an external circuit. The word photocell is now commonly used to describe photoconductive or photovoltaic devices.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
A solid-state photosensitive electron device whose current-voltage characteristic is a function of incident radiation. Also known as electric eye; photoelectric cell.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
a device in which the photoelectric or photovoltaic effect or photoconductivity is used to produce a current or voltage when exposed to light or other electromagnetic radiation. They are used in exposure meters, burglar alarms, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
photocellA device that detects light. Used for photographic light meters, automatic on-at-dusk street lights and other light-sensitive applications, a photocell varies its resistance between its two terminals based on the amount of photons (light) it receives. Also called a "photodetector," "photoresistor" and "light dependent resistor" (LDR).
The photocell's semiconductor material is typically cadmium sulfide (CdS), but other elements are also used. Photocells and photodiodes are used for similar applications; however, the photocell passes current bi-directionally, whereas the photodiode is unidirectional. See photodiode.
|Light Dependent Resistors|
|Photocells come in a variety of packages such as this assortment from PerkinElmer. As the photocell receives more photons, the resistance is lowered between the two terminals. (Image courtesy of PerkinElmer, Inc., www.perkinelmer.com)|
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