What type of circuit requires a fuse or circuit breaker?

In electrical systems, a series circuit requires a fuse or circuit breaker primarily for safety and protection purposes. A series circuit is defined as a type of circuit where components are connected one after another in a single path, meaning the same current flows through all components. In the event of excessive current due to a fault (such as a short circuit or overload), the risks of overheating and potential fire hazards increase significantly.

Fuses and circuit breakers are protective devices designed to interrupt the electrical flow when the current exceeds a preset level. By doing so, they prevent potential damage to the circuit and its components, and ensure user safety. In a series circuit configuration, where all components have the same current, if one component experiences a fault and allows a surge in current, the fuse or circuit breaker will act to disconnect the power, thereby protecting the entire circuit.

While other types of circuits, such as parallel circuits and closed circuits, can also utilize protective devices, the emphasis here is on the unique current flow and potential hazards associated with series circuits that make the presence of a fuse or circuit breaker essential for reliable operation and safety.