Which measurement is usually expected when testing a blown fuse?

When testing a blown fuse, the expected measurement is full voltage and no current. This is because when a fuse is blown, it interrupts the circuit, preventing current from flowing. Therefore, if you measure the voltage across the fuse terminals, you will see the full voltage that is applied to the circuit, as the supply is still connected, but the interruption caused by the blown fuse means that there is no current passing through.

In practical terms, the measurement indicates that the electric potential is present, but the circuit is open due to the blown fuse, resulting in no current flow. This understanding is crucial for diagnosing electrical issues, as it helps technicians confirm that the fuse has indeed failed.