Diodes Characteristics And Applications

A photodiode is specifically designed to detect light (optical signals). When photons hit the photodiode, they generate electron-hole pairs, creating a photocurrent proportional to the intensity of the light. Zener diodes are used for voltage regulation, and light-emitting diodes (LEDs) emit light when current flows through them. Transistors are used for amplification and switching, not for detecting light. Thus, the correct answer is .