Which of the following is a functionality of a relay in an electrical circuit?

A relay serves several important functions in an electrical circuit, but one of its primary roles is to provide isolation. When a relay is activated, it can open or close contacts to control another circuit without any physical connection between them. This isolation is particularly beneficial because it protects sensitive components from high voltages or currents and allows for control of high-power devices using low-power signals.

While relays can also influence other aspects of a circuit, such as controlling voltage levels by switching circuits or controlling the operation of devices like motors, the core functionality of providing isolation is crucial for ensuring the safety and integrity of electrical systems. In doing so, relays help manage the interactions between different parts of a circuit effectively.

The other functionalities listed, while they may be relevant in certain contexts, do not embody the primary purpose of a relay in terms of electrical isolation and safety.