Photodiode facts for kids
A photodiode is a light sensitive semiconductor. It is a type of photodetector capable of changing (or converting) light into either current or voltage, depending upon the mode of operation. If the anode and cathode leads of a photodiode are joined together by a wire, when in the dark, no current will flow. On the other hand, when in the light, current flows from the cathode to the anode. The diode part of a photodiode allows current to flow in only one direction.
Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas. Photodiodes usually have a slower as its surface area increases. The common, traditional solar cell used to generate electric solar power is a large area photodiode. Photodiodes and look the same physically but have different functions.
It is based on a reversed bias circuit.
Images for kids
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I-V characteristic of a photodiode. The linear load lines represent the response of the external circuit: I=(Applied bias voltage-Diode voltage)/Total resistance. The points of intersection with the curves represent the actual current and voltage for a given bias, resistance and illumination.
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A one-dimensional photodiode array chip with more than 200 diodes in the line across the center
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A two-dimensional photodiode array of only 4 × 4 pixels occupies the left side of the first optical mouse sensor chip, c. 1982.
See also
In Spanish: Fotodiodo para niños
