What is the primary function of a diode?

The primary function of a diode is to allow current to flow in one direction only. Diodes are semiconductor devices that create a unidirectional flow of electric current by having a positive (anode) and a negative (cathode) side. When the voltage is applied in the forward bias direction (positive to the anode and negative to the cathode), the diode conducts electricity. Conversely, if the voltage is reversed, the diode blocks the current. This property makes diodes essential in various electronic circuits, such as rectifiers, which convert alternating current (AC) to direct current (DC), by only allowing the current to pass through in one direction.

In contrast, while some diodes can be used in rectification, their primary function is about controlling the direction of current flow rather than storing energy, amplifying signals, or specifically converting AC to DC, which is a broader role involving additional components.