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Photocells


Photocells are a type of sensor designed to detect the presence of light. They are small inexpensive accessories that can be used with light fixtures to turn them on or off depending on the time of day. We offer many different types and styles of photocells in our Lighting category.
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MP39063 MP39056 MP39057
MP39030 MP39050 MP39058
MP39040 MP39069 MP39060
MP39010 MP39070 MP39012
MP39020 MP39032 MP39052
MP39053 MP39042 MP39011
MP39022 MP39051 MP39062
MP39013 HLP Photocontrol, Twist Lock MV Utility (Long Life Version), 120-277VAC MP39072
   
 
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History of Photocells


The modern photocell has remained mainly unchanged since they were first invented and introduced over 40 years ago. The main reason they were invented was to control outdoor lighting fixtures so that they were lit dusk to dawn, therefore saving power and the bulb's lifespan. The operation of a photocell is fairly simple. There is a current flowing through a closed electromagnetic relay. When the cell is exposed to sunlight the resistance is zero and therefore there is no current flowing to the fixture. When the sunlight is gone the opposite happens and power flows freely to the light.