What is Photodiode: Definition and 72 Discussions

A photodiode is a semiconductor p-n junction device that converts light into an electrical current. The current is generated when photons are absorbed in the photodiode. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas. Photodiodes usually have a slower response time as their surface area increases. The common, traditional solar cell used to generate electric solar power is a large area photodiode.
Photodiodes are similar to regular semiconductor diodes except that they may be either exposed (to detect vacuum UV or X-rays) 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 specially as a photodiode use a PIN junction rather than a p–n junction, to increase the speed of response. A photodiode is designed to operate in reverse bias.

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  1. R

    How to convert photodiode voltage to any photonic unit

    How can I convert the voltge measured across a photodiode to light output or intensity or any other photonic unit? I am trying to measure the light intensity/output of some LEDs using a photodiode but the photodiode measures voltage as a function of light intensity.
  2. P

    Calculating Irradiance from BPW21R Photodiode Current

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  3. K

    Understanding the Significance of Photodiode Bandwidth | Lab Tips

    What does the bandwiidth of a photodiode signify? I just know that it is related to speed of photodiode, but while dealing with PD practically in lab. , what does its bandwidth tell me ?
  4. B

    Photodiode Sampling: How Does Wavelength Affect Plate Saturation

    I am curious how does the wavelength of light let's say 800nm/s collected by a photodiode results from the saturation of the plate 1mm. sq. I have this photodiode from a cdrom and it has 6 legs, two do not have a bias-junction, the other four do, and the collector is slightly greenish. I...
  5. J

    Calculating photodiode current and voltage

    Hi I'm pretty new to the forums. I've been searching and can't find anything on this. Can anyone show me how to calculate the current/voltage produced by a photodiode?
  6. M

    Help required for surface reflection circuit (IR-LED/ PHOTODIODE)

    Hi I am new to this forum but have been interested in reading many threads and would like to know if any of the experts could help. I am looking to make a circuit that I can measure different output levels of a photodiode from the amount of "signal" reflected onto it from a particular...
  7. A

    4-20mA photodiode circuit

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  8. M

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  9. Topher925

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  10. J

    Need Help wiring a photodiode to measure light

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  11. B

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  12. B

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  13. C

    Time constant of photodiode? parallel stray capacitance?

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  14. S

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  15. S

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  16. S

    Photodiode & EMF: Is This Correct?

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  17. C

    The + sign above the photodiode, what does it mean?

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  18. S

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  19. T

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    HI all, i'm currently working with IR sensor diodes, and trying to find a proper device for my project, however i haven't found a good unit which fills my needs. Now that i have extended my search to phototransistors, i wonder are they compatible with photodiodes? Im using Atmel's...
  20. R

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  21. M

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  22. I

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    Hello, I am having a bit of trouble with the following problem: Assuming a built in voltage equal to the bandgap voltage, calculate the slowest possible transmit time for a carrier with 5V reverse bias applied to the GaAs photodiode. I would be able to do this problem without difficulty if...
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