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Photodiode is operated under:

Photodiode is operated under: Correct Answer Reverse bias

CONCEPT:

Photodiode:

  • A Photodiode is a special purpose p-n junction diode fabricated with a transparent window to allow light to fall on the diode.
  • It is operated under reverse bias.
  • When the photodiode is illuminated with light (photons) with energy (hν) greater than the energy gap (Eg) of the semiconductor, then electron-hole pairs are generated due to the absorption of photons.
  • The diode is fabricated such that the generation of e-h pairs takes place in or near the depletion region of the diode.
  • Due to the electric field of the junction, electrons and holes are separated before they recombine.
  • The direction of the electric field is such that electrons reach the n-side and holes reach the p-side.
  • Electrons are collected on the n-side and holes are collected on the p-side giving rise to an emf.
  • When an external load is connected, current flows.
  • The magnitude of the photocurrent depends on the intensity of incident light (photocurrent is proportional to incident light intensity).
  • If a reverse bias is applied. Thus photodiode can be used as a photodetector to detect optical signals.

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EXPLANATION:

  • From the above, it is clear that Photodiode is operated under reverse bias. Hence, option 2 is correct.

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