photocell


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Related to photocell: photovoltaic cell, solar cell

photocell:

see photoelectric cellphotoelectric cell
or photocell,
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.

photocell

[′fōd·ə‚sel]
(electronics)
A solid-state photosensitive electron device whose current-voltage characteristic is a function of incident radiation. Also known as electric eye; photoelectric cell.

photocell

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.

photocell

A 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)
References in periodicals archive ?
Consequently, the real current, I, produced by the photocell will be related to the idealized current, [I.
In addition, the CdS Photocell Series can provide a cost-effective solution in many light-switching applications.
To "assess" some combination of scenes on the live screen and video-taped displays of "stored information" on another monitor, photocells are trained on various parts of the monitor screens.
A There are two ways to effectively control exterior lighting: A timer clock and a photocell for detecting light and dark.
To date, there have been no failures due to fixtures; four failures due to photocell failure; and four failures due to improper grounding of the fixture.
With its patent pending photocell technology integrated into the head of the light, Wave Light will be able to detect the light conditions and automatically adjust the power settings according to the current environment.
We can't find any CFL bulbs that work with a photocell.
An independent servomotor, interacting with the notch detecting photocell, controls the film drive and adjusts the label dispensing speed by comparing the actual printing speed with the speed stored in the format menu.
This automatic feature can be set to one of two modes, timer or photocell.
It operates at a speed of 12 feet per minute and features a three-position rocker switch, pilot lights, and a photocell eye that automatically starts and stops the machine.
The resulting energy savings are reduced when photocell sensitivity is degraded.