What happens to the metal strip in a fuse when excess current passes through it?

When excess current passes through a fuse, the metal strip within the fuse undergoes a significant temperature increase due to the electrical resistance it offers to the current flow. As the current exceeds the rated capacity of the fuse, the heat generated becomes intense enough to cause the metal strip to reach its melting point.

Once this threshold is reached, the metal strip melts, effectively breaking the circuit and stopping the flow of electricity. This is a crucial safety mechanism, as it prevents potential damage to electrical components or fires that could occur from excessive current. The melting of the strip serves as a physical indication that the fuse has blown, necessitating replacement for proper system protection.

This process relies on the principle that metals have a specific amount of current that they can safely carry; exceeding this current leads to the melting of the conductive material, effectively interrupting the power supply.