Photodiode Responsivity Formula and Calculator

Photodiode responsivity is a critical parameter for evaluating the efficiency of photodiodes in converting light into electrical current. This guide provides a clear explanation of the responsivity formula and how to calculate it. With our calculator, you can quickly and accurately determine the performance of photodiodes for various applications.

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 formula is used in this calculator to measure Photodiode Responsivity.

Conclusion

Understanding photodiode responsivity is essential for designing and optimizing optical systems. By using the formula and calculator provided, you can ensure precise measurements and enhance the performance of your photodiode applications.

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