What does photocell mean?
A photocell is a light-sensitive electronic device that converts incoming light into an electrical signal. Depending on its construction, that signal may take the form of current, voltage, or a change in resistance. Photocells are used in automatic lighting, exposure meters, counters, optical readers, security systems, and many industrial sensors. The term is broad rather than highly specific: it can refer to a photoelectric cell generally, although particular technologies such as photodiodes and photoresistors have their own names. In everyday descriptions, a photocell is often presented as a simple device in which light produces a current, but modern sensors may instead respond through more complex changes in their electrical properties. Its enduring usefulness comes from allowing machinery to detect and measure light automatically, without a person having to observe or adjust the light directly.
nounAn electronic device or component that detects light and produces an electrical response, such as a current, voltage, or change in resistance.
- An electronic device or component that detects light and converts it into an electrical response.
"A photocell switched the floodlights on as the sun went down."
"A photocell switched the floodlights on as the sun went down."
"The camera's automatic exposure system uses a photocell to measure the light."
The regular plural is “photocells.”
"Several photocells are positioned along the edge of the conveyor belt."
A photocell is a literal light-to-electricity translator: it turns an invisible beam of photons into a signal a machine can use.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does photocell come from?
The first element of photocell, photo-, comes from Greek phōs, meaning “light,” and is the same root found in photograph and photosynthesis. Cell entered English from Old French celle, ultimately from Latin cella, meaning “small room” or “storeroom,” and was later extended to refer to small structural or biological units. In photocell, this older word was combined with the light-related prefix to name a small device that responds electrically to light.
Related word forms
How photocell is actually used
The term is chiefly used in technical contexts. The fuller expression “photoelectric cell” is common in formal and historical writing.
Easily confused with photocell
A photodiode is a semiconductor photodetector, whereas photocell is a broader term for any device that produces an electrical response to light.
A photoresistor detects light by changing its resistance, while the term photocell can include several other kinds of light-sensitive electrical devices.