photodiode

n. light-sensitive semiconductor diode, rectifier containing a photosensitive semiconductor (Electronics)

A photodiode is a semiconductor diode that functions as a photodetector. Photodiodes are packaged with either a window or optical fibre connection, in order to let in the light to the sensitive part of the device. They may also be used without a window to detect vacuum UV or X-rays.A phototransistor is in essence nothing more than a bipolar transistor that is encased in a transparent case so that light can reach the base-collector junction. The phototransistor works like a photodiode, but with a much higher responsivity for light, because the electrons that are generated by photons in the base-collector junction are injected into the base, and this current is then amplified by the transistor operation. However, a phototransistor has a slower response time than a photodiode.
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A semiconductor diode that produces, as a result of the absorption of photons, (a) a photovoltage or (b) free carriers that support the conduction of photocurrent. Note: Photodiodes are used for the detection of optical communication signals and for the conversion of optical power to electrical power.

B: (Kimia) fotodiode
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B: (Fisika) fotodiode
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