I am reading photo diode and I have couple of questions in. So my understanding of a photodiode is that these are devices which consume electricity and produce light

  1. So if that being the case, I am assuming there is no battery involved in the circuit. this diode will act as a battery and supply current. If that being the case what is the meaning when we say these diodes are designed to work in reverse bias condition. How is forward bias and reverse bias coming to picture here?

  2. Generally the working principle of a photodiode is explained by saying that When a photon of sufficient energy strikes the diode, it creates an electron-hole pair and due to the internal electric field at junction holes in the region move toward the anode, and electrons move toward the cathode, and a photocurrent is generated. So the current is driven by the electric field at the junction.? Is it strong enough to drive the current in the circuit.? Also, why does the recombination not happen with holes when electrons move towards N side.?

  • 1
    $\begingroup$ Sorry, I'm a bit confused. A photodiode is a type of light detectors. You seem to be asking about diodes in general, that is, a PN junction. Am I right? $\endgroup$
    – FGSUZ
    Jan 18, 2019 at 22:39
  • $\begingroup$ Yes, a photodiode and a photovoltaic cell are in principle the same thing, but a photodiode detector is often used in reverse bias. $\endgroup$
    – user137289
    Jan 18, 2019 at 22:50
  • $\begingroup$ Related: Doubt about the working principle of a silicon solar cell $\endgroup$
    – The Photon
    Jan 19, 2019 at 2:06


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