What is a diode?

A diode is a semiconductor device that allows electrical current to flow in only one direction. This characteristic makes it an essential component in various electronic circuits, where it is used to control the direction of current flow. By permitting current to pass through in a single direction while blocking it in the opposite direction, diodes help protect circuits from damage due to reverse polarity.

In applications such as rectification, where alternating current (AC) is converted to direct current (DC), diodes play a crucial role in ensuring that current flows correctly and efficiently. This directional property of a diode is what differentiates it from other circuit elements, which may allow current to flow freely in both directions or may not even conduct electricity at all.

Understanding the function of a diode is foundational in electronics, particularly in designing circuits that require controlled power flow and managing voltage levels.