What is the purpose of a fuse in an electrical circuit?

The purpose of a fuse in an electrical circuit is to protect against overloads. Fuses act as safety devices that interrupt the flow of electricity when the current exceeds a certain level. By doing this, they help prevent damage to electrical components and reduce the risk of fire caused by overheating or excessive current flow. When the electrical load surpasses the designed limit, the fuse melts and breaks the circuit, stopping the current and thus protecting sensitive devices from potential harm. This functionality is essential in maintaining the safety and integrity of electrical systems.

In contrast, the other options describe functions that do not align with the primary role of a fuse. Increasing current would lead to potential damage and is not a function of a fuse. Decreasing voltage does not pertain to a fuse's operation; instead, transformers or voltage regulators perform that function. Lastly, improving power factor relates to the efficiency of power usage in AC circuits, typically managed by capacitors or inductors rather than fuses.