When a fuse is blown, what happens to the circuit in terms of voltage and current?

When a fuse is blown, the circuit experiences a break in the electrical continuity, which leads to an interruption of the current flow. As a result, the current in the circuit stops completely. While the voltage could still be present at certain points in the circuit, its effective application drops because the path for current flow has been disrupted. Therefore, the voltage remains the same at the source, but because the current has ceased, the overall current through the fused area is effectively zero.

This situation highlights the protective role of the fuse; it is designed to open the circuit (blow) in the event of excessive current flow, thereby protecting the wiring and connected devices from damage. Understanding this function is critical, as it shows how safety mechanisms in electrical systems work to prevent overheating and potential fire hazards.