Which of the following components is NOT typically used in a power supply?

In a power supply, the primary components include diodes, capacitors, and resistors, each serving essential roles in converting and regulating electrical power. Diodes are used to rectify alternating current (AC) into direct current (DC), enabling the power supply to function efficiently. Capacitors smooth out voltage fluctuations and store electrical energy, providing stability to the power output. Resistors may be used to limit current or to form voltage divider circuits.

Relays, while they can be part of certain electronic systems, are typically not found in basic power supply designs. A relay is an electromechanical switch, primarily used to open or close circuits and provide isolation between different parts of a system. Although it can control high-power circuits, its primary function does not fit the essential role within a standard power supply, which focuses on voltage transformation and regulation rather than circuit switching. Consequently, the relay is the component that is not typically used in a power supply configuration.