Photodiode Responsivity Formula — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Photodiode Responsivity Formula This formula is used when measuring the sensitivity of a photodetector (like a photodiode) by relating the generated electrical current to the incident optical power. Responsivity (R) is defined as the ratio of generated photocurrent (I ph) to incident optical power (P opt). The photocurrent is generated by the photoelectric effect, where incident photons create electron-hole pairs. The number of generated electrons is proportional to the incident power divided by the energy per photon (E = h ). The proportionality constant includes the quantum efficiency ( q) and the elementary charge (q). P opt > 0 I ph 0 Confusing responsivity (R) with quantum efficiency ( q). Responsivity accounts for the entire system (including charge collection efficiency), while q is purely based on photon absorption. Assuming the responsivity is independent of the wavelength of light used. Forgetting that the formula relates to the ratio of current to power, not just current to intensity.