Semiconductor fuses are designed to protect sensitive electronic devices such as diodes, thyristors, and transistors, from damage caused by overcurrent and short-circuits. They operate much quicker than ordinary fuses, generally in milliseconds, dramatically reducing the energy let-through (I²t) during a short-circuit. The rapid response is necessary for semiconductors as they can be damaged by electrical surges that may only last for milliseconds. In the event of an overcurrent fault, the semiconductor fuse will interrupt the circuit almost instantaneously, so the delicate internal components do not incur excessive heat or electrical stress. Semiconductor fuses offer the first line of protection for the circuit or semiconductor devices, help with system reliability and costly downtime, and assist with protecting equipment that is much more expensive than the fuse.