What is the primary function of a diode?

The primary function of a diode is to allow current to flow in one direction only. This unidirectional property is crucial in many electronic circuits, as it enables diodes to control the flow of current, protecting components and ensuring that circuits operate correctly. When a diode is forward-biased (where the positive side is connected to the anode and the negative side to the cathode), it conducts electricity, allowing current to pass through. Conversely, when it is reverse-biased, it prevents current from flowing, effectively blocking it. This characteristic makes diodes essential for tasks such as rectification in power supplies, where alternating current (AC) needs to be converted to direct current (DC).

The nature of a diode's operation ensures that current can only pass in one direction, which is fundamental for the correct functioning of many electronic devices and circuits.