The photodiode is an optical diode which operates in reverse bias condition. Today you’ll learn the basic working and practical applications of the photodiode.
List of Contents
How Photodiode works
A photodiode is an optical diode whose resistance varies with the intensity of light. Under the ordinary condition, the resistance of photodiode is very high and the current flowing through the diode is negligible. With an increase in the intensity of light the reverse biased current flowing through the diode increases.
How it looks and its symbol
What you should know
The actual current flow of the photodiode (in other words resistance) is determined by irradiance. Irradiance is the intensity of light falling on the diode. The actual relationship between irradiance and resistance is determined from the graph of the diode and it can vary based on different models. Generally, a resistance of 8 MΩ is expected at 0.5 mW/cm2 and a resistance of 100-200 kΩ is expected around at 20 mW/cm2.