What is a Photocell?

A photocell is any of a wide range of sensors that react based on the presence of light or electromagnetic energy. A photocell can be found in many different forms, from solar panels that use light to generate electricity, to photoresistors, which shift in resistance based on how much light is present. The photocell is one of the most important modern technological advancements, allowing for a whole range of new technologies to be created. One of the most common types of photocell is the photoresistor. A photoresistor is a device which is constructed out of a semiconductor of high resistance. When enough light hits the semiconductor, it absorbs enough photons that the electrons already present have enough energy to conduct, lowering resistance. A photoresistor may be either intrinsic, such as those made of silicon, in which case it will require a fair amount of light to lower the resistance, or extrinsic, with a dopant added to lower the amount of energy needed to trigger a reaction, ...  more

A photocell is basically an electronic device that detects light and sends a signal when exposed to light.  more

A Photocell is a light sensor that varies its resistance between its two light terminals based on the amount of light it receives. In other words, it is a sensor – or an “eye” that detects light - which turns your Outdoor fixture on when receiving less light (usually around dusk) and turns it off when receiving more light (usually around dawn). Fixtures that come equipped with a Photocell are often referred to as "Dusk-to-Dawn" lights.  more

A Photocell is a light sensor that varies its resistance between its two light terminals based on the amount of light it receives. In other words, it is a sensor – or an “eye” that detects light - which turns your Outdoor fixture on when receiving less light (usually around dusk) and turns it off when receiving more light (usually around dawn). Fixtures that come equipped with a Photocell are often referred to as “Dusk-to-Dawn” lights.  more