What Is a Photocell?
Photocell is a light-sensitive electrical control that switches outdoor lighting on when surrounding light fades and off when daylight returns. The device uses a sensor to detect ambient brightness and send a control signal to a lighting circuit. It helps automate exterior fixtures without requiring manual operation at each switch.
Quick Facts About Photocell
Category
Light-sensitive electrical control
Used for
Automatic outdoor lighting
Common confusion
Not a motion sensor
Also called
Photoelectric sensor, Dusk-to-dawn sensor
Often discussed with
Outdoor Lighting Installation
Key Takeaways About Photocell
- Light sensing distinguishes a photocell from a standard timer.
- Placement affects when the connected fixture switches.
- A photocell is not the same as a motion sensor.
How Photocell Works
A photocell contains a light-sensitive sensor that responds to ambient brightness. As daylight fades, the control changes the electrical state of the connected lighting circuit, allowing the fixture to turn on. When daylight returns, the sensor changes state again and the fixture turns off.
Related glossary terms: Line Voltage.
Photocells respond to available light, while a timer switch follows scheduled settings. A motion sensor responds to movement within its detection area. Installers consider the sensor's direction and nearby light sources because a porch fixture, window, or reflected light can affect its reading. Proper wiring also keeps the sensor from receiving light directly from the fixture it controls.
From the Santa Ana Electrician team
When we install outdoor lighting, we check the photocell location, wiring, and sensor orientation. We look for nearby fixtures or reflective surfaces that could keep the sensor from reading daylight accurately. Our team also tests the connected light during changing conditions or with a suitable test method.
Photocell in Practice: A Real-World Example
A homeowner wants a pathway light to operate automatically each evening. An electrician installs a photocell where surrounding daylight reaches the sensor, then connects it so the fixture turns on as the area darkens and turns off after daylight returns.
Related Services
Related Terms
Line Voltage
Line Voltage is the electrical potential supplied directly by a building’s power system to operate equipment…
Santa Ana Electrician
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