Which component is used to rectify current in an electrical circuit?

The component that is primarily used to rectify current in an electrical circuit is the diode. Diodes are semiconductor devices that allow current to flow in one direction while blocking it in the opposite direction. This property makes them essential in converting alternating current (AC), which flows in both directions, into direct current (DC), which flows in a single direction.

When AC voltage is applied to a diode, it only allows the positive half-cycles of the AC wave to pass through, effectively "clipping" the negative half-cycles and transforming the AC waveform into a pulsating DC signal. This process is fundamental in power supply circuits, where AC voltage from power outlets is commonly converted to usable DC voltage for electronic devices.

Other components listed have different primary functions: resistors are used to limit current, capacitors store electrical energy, and transformers change the voltage level of AC power but do not rectify current. The specific role of a diode in rectification is pivotal to understanding how many electronic devices and power supplies operate.