Difference between photodiode and phototransistor

One major difference between the photodiode and the phototransistor is that photodiode consist of a normal P-N junction diode which a transparent window through which light can fall inside whereas in phototransistor uses a transistor which controls by exposure to light. This article is about photodiode vs phototransistor and also the comparison between the photodiode and phototransistor and also mentions the key the difference between them.

  • We all know that a photodiode is a P-N junction type of diode and it can generate electric current when light or photon is incident on their surface.
  • A photodiode is only generated current.
  • When we have to use a photodiode output response is too much fast.
  • Sensitivity is less when we have to use a photodiode.
  • A photodiode is working both forward as well as reverse biasing.
  • The photodiode is generating solar power, detecting ultraviolet or infra-rays for measuring light etc.
  • The phototransistor is one type of transistor which can convert the light energy into electrical energy.
  • A phototransistor has generated both voltage and current.
  • Output response is slow when we have to use a phototransistor.
  • Sensitivity is more.
  • A phototransistor is only working forward biasing.
  • A phototransistor is used in a smoke detector, compact disc players, an invisible light receiver and LASER etc.
Difference between photodiode and phototransistor :
  • A photodiode is a semiconductor device while phototransistor use as the transistor.
  • Photodiode which can convert the light energy into an electrical current, whereas the phototransistor is for the conversion of light energy into an electrical current.
  • A photodiode is more responsive to incident light than a phototransistor.
  • Photodiode work in both forward as well as reversed bias whereas the phototransistor work in forward biasing.
  • The phototransistor is used as a solid state switch, detecting the light whereas the photodiode is used in solar power plant, in a light meter etc.
  • A phototransistor is more sensitive than a photodiode about one hundred times.
  • Photodiodes pass less current compared to phototransistor while in photodiode consumes less current than a phototransistor.
  • The dark current of the phototransistor is much higher than a photodiode.
  • The photodiode has a linear response over a much wider range of light than a phototransistor.
  • Photodiode produces both voltage and current while phototransistor generates only for current.