Semiconductor devices, with their small mass, have limited overload capacity, so a fuse used with them must be the weakest circuit link. It must blow before the internal semiconductor leads or before the wafer ruptures. The semiconductor fuse responds rapidly to instantaneous peak currents, as opposed to types that handle surges and only blow under continued overload. In fact, what distinguishes the semiconductor fuse from others is its rapid response time and its ability to limit the energy passed to the protected device.