What electronic component allows current to flow in only one direction?

A diode is a semiconductor device that allows current to flow in only one direction. This characteristic is crucial for various applications in electronic circuits, including rectification, where alternating current (AC) is converted into direct current (DC). The diode achieves this functionality by using p-n junctions, where one side is made of p-type material (which has an abundance of holes, or positive charge carriers) and the other side is n-type material (which has an excess of electrons, or negative charge carriers). When forward-biased, meaning the p-side is connected to a higher voltage than the n-side, the diode conducts current. However, when reverse-biased, it blocks current flow, thus ensuring that electricity travels in a single direction.

The other components listed have different roles in electronic circuits. A resistor restricts the flow of current, a fuse acts as a safety measure to break the circuit if the current exceeds a certain level, and a driven element typically refers to a component in antennas, which does not have the unidirectional current flow property of diodes.