What is a diode?

A diode is defined as a semiconductor device that allows current to flow in only one direction. This characteristic is fundamental to its operation, as it creates a pathway for electrical current to move in a designated direction while blocking it from flowing in the opposite direction. This directional property is essential in many electronic applications, such as rectification, where alternating current (AC) needs to be converted to direct current (DC).

Diodes typically consist of a p-n junction, which is formed by layering p-type (positive) and n-type (negative) semiconductor materials. When forward-biased (with voltage applied in the appropriate direction), the diode conducts current. When reverse-biased, it prevents current flow, effectively acting as a switch that controls the direction of current.

This unique function makes diodes critical components in various circuits, including power supplies and signal modulation devices. Understanding the role of a diode within an electrical circuit is key for anyone studying electricity and electronics, as it forms the basis for more complex components and systems.