Photodiode Responsivity Definition, formula, calculator

This page describes Photodiode Responsivity definition, Photodiode Responsivity formula and Photodiode Responsivity calculator.

What is Photodiode ?

• A photodiode is a type of photodetector capable of converting light into either current or voltage. This effect is called photovoltaic effect.
• DC source is often used to apply reverse bias to the photodiode. This makes it generate more current. This mode of operation is called photoconductive mode.
• Applications of photodiode include optical disc drives, digital cameras and optical switches etc.
• Variants : PIN photodiode, Avalanche photodiode, PN Photodiode, Schottky Photodiode etc.

The figure depicts symbol of Photodiode and one such device from OSRAM. Refer article on Photodiode basics and types and their working operation.

What is Photodiode responsivity ?

Definition: The responsivity of silicon photodiode is a measure of sensitivity to light. It is defined as ratio of photocurrent (I_p) to incident light power P at given wavelength.

Responsivity, R_λ = I_p/P

In other words, it is measure of the effectiveness of conversion of light power into electric current. It varies with the wavelength of incident light, applied reverse bias and temperature.

Photodiode Responsivity Calculator

Example of Photodiode Responsivity calculator:
INPUTS : Ip = 50 mA, P = 500 mWatt
OUTPUTS: Responsivity = 0.1

Photodiode Responsivity Formula

Following Photodiode Responsivity formula is used in this calculator on Photodiode Responsivity.

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