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

A diode is a semiconductor device that permits current to flow primarily in one direction. This unidirectional behavior is essential in various electronic applications, such as rectification, where alternating current (AC) is converted to direct current (DC). The diode accomplishes this by having a p-n junction that allows charge carriers (holes and electrons) to move through the junction in one direction, thereby blocking current flow in the reverse direction.

In practical applications, diodes are used in circuits to protect components by preventing reverse current that could cause damage. This characteristic is fundamental to many electronic devices, such as power supplies and signal modulators, highlighting the importance of diodes in electronic design.

The other components listed, such as resistors and fuses, do not have a unidirectional current property. A resistor limits current regardless of the direction, and a fuse acts as a safety device that opens the circuit when current exceeds a certain level, but again, it does not control the direction of current flow. A driven element, typically found in antenna systems, serves a different function related to radiation and reception of radio waves.