What does photodiode mean?
A photodiode is a semiconductor device designed to detect light. When photons strike its active region, they generate charge carriers, producing a current or changing the device's electrical resistance. These changes can be measured to determine light intensity or used to convert optical signals into electrical signals for processing. Photodiodes are used in optical communications, light meters, scanners, cameras, industrial sensors, and precision timing systems. They may operate without an external supply, with the light itself producing a current, or under reverse bias to obtain a faster and more linear response. Although a photodiode and a solar cell both respond to light, their main purposes differ: photodiodes are generally optimized for detection and measurement, whereas solar cells are intended to deliver useful electrical power.
nounA light-sensitive semiconductor device that converts incoming light into an electrical current or signal. It is commonly used to detect light, measure its intensity, and convert optical signals into electrical ones.
- A semiconductor device that detects light by producing or changing an electrical current in response to incoming photons.
"The camera's photodiode array measured the light reflected from the page."
"A photodiode converted the modulated light beam into an electrical signal for the receiver."
"The laboratory used a photodiode to measure how the laser's intensity changed over time."
The regular plural adds "-s" to the complete word.
"Several photodiodes were arranged in a row across the detector."
A photodiode can detect light without external power: photons themselves can produce the electrical current it measures.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does photodiode come from?
Photodiode is a modern technical compound formed from the combining form photo-, derived from Greek phōs, meaning "light," and diode, a term coined from Greek roots meaning "two-way." The combining elements joined the established names of photoelectric and diode technologies to describe a diode capable of responding to light. Its related terms photograph and photography share the Greek light-forming element, while diode belongs to the same electrotechnical vocabulary as anode, cathode, and electrode.
How photodiode is actually used
This is a specialist engineering term, especially common in electronics, optics, telecommunications, and imaging. It is normally written as one word, although hyphenated forms such as "photo-diode" occur in older or less standardized technical writing.
Easily confused with photodiode
A photodiode generates a current directly in a semiconductor junction, whereas a phototransistor uses incident light to control current through a transistor.
A solar cell is designed primarily to generate electrical power from light, while a photodiode is generally used for light detection, measurement, or optical signalling.