A photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation.Photo diodes are similar to regular semiconductor diodes except that they may be either exposed or packaged with a window or optical fiber connection to allow light to reach the sensitive part of the device. Many diodes designed for use specifically as a photo diode will also use a PIN junction rather than the typical PN junction.
Working:-
A photodiode is a PN junction or PIN structure. When a photon of sufficient energy strikes the diode, it excites an electron, thereby creating a free electron and a (positively charged electron hole). This mechanism is also known as the photoelectric effect. If the absorption occurs in the junction's depletion region, or one diffusion length away from it, these carriers are swept from the junction by the built-in field of the depletion region. Thus holes move toward the anode, and electrons toward the cathode, and a photo current is produced. This photocurrent is the sum of both the dark current (without light) and the light current, so the dark current must be minimised to enhance the sensitivity of the device.
1)P-N photodiodes are used in similar applications to other photo detectors.
2)Photo diodes are used in consumer electronics devices such as compact disc players, smoke detectors, and
4)PIN diodes are much faster and more sensitive than ordinary p-n junction diodes, and hence are often used
5)P-N photodiodes are not used to measure extremely low light intensities. Instead, if high sensitivity is
Applications:
2)Photo diodes are used in consumer electronics devices such as compact disc players, smoke detectors, and
the receivers for remote controls in VCR's and televisions.
3)In other consumer items such as camera light meters, clock radios (the ones that dim the display when it's
3)In other consumer items such as camera light meters, clock radios (the ones that dim the display when it's
dark).
4)PIN diodes are much faster and more sensitive than ordinary p-n junction diodes, and hence are often used
for optical communications and in lighting regulation.
5)P-N photodiodes are not used to measure extremely low light intensities. Instead, if high sensitivity is
needed, avalanche photo diodes,intensified charge-coupled devices or photomultiplier tubes are used for
applications such as astronomy, spectroscopy, night vision equipment and laser rangefinding.
8 comments:
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@ Hack hacker
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