What is a diode?

A diode is a semiconductor device that allows current to flow in one direction only, which is essential for rectification in electronic circuits. This unidirectional behavior is attributed to the diode's structure, which consists of a p-n junction. When the anode is positive relative to the cathode, the diode becomes forward-biased, allowing current to pass through. Conversely, when reverse-biased, it blocks current flow, making diodes crucial for controlling the direction of current in circuits.

This capability is vital in applications such as converting alternating current (AC) to direct current (DC), protecting circuits from reverse voltages, and managing signal flow in various electronic devices. The distinction of a diode's function is significant as it differs fundamentally from components like amplifiers, resistors, and capacitors, which serve different roles in electronic circuits.