Difference Between HRC Fuse & Semiconductor Fuse

http://en.wikipedia.org/wiki/HRC_Fuse

Semiconductor fuses are faster and have lower I²t than normal HRC fuses. Quoting from Cooper-Bussmann....

_{FUSE LINKS FOR THE PROTECTION OF SEMICONDUCTORS
The term semiconductor in electrical circuits can best be described as a switch, however unlike the domestic light switch, there are no moving parts. When a small amount of electricity is applied to one part of the semiconductor, the complete device changes from being an insulator (a material that does not pass electric current) to a conductor (a material that does pass electric current). Like many other circuit components, the semiconductor is sensitive to excesses in both current and voltage. When an over-current is evident the wafer thin sections of the device over-heat and are damaged. Similarly, when the current is not flowing through the device, but a high circuit voltage is present, the construction of the device will again be damaged.}

_{Semiconductors were first marketed in 1953, and it was realised from the outset that these devices had very limited overload capacities and, as they were expensive, the Fuse manufacturers attempted to produce Fuse Links which were more sensitive to overloads and which would operate more quickly than their conventional designs. Fuse Links designed to protect semiconductors incorporate elements machined to finer tolerances and rarely employ the M-effect as used in the Industrial range. A Fuse Link element with finer tolerances will reduce the ability of the Fuse to provide low over-current protection, and will therefore provide increased protection to the semiconductor. As a consequence of interrupting the current flow more quickly, an over-voltage is produced by the Fuse Link. This voltage must be limited or other circuit components (including the semiconductor) could be damaged. To limit this over-voltage, additional bonding agents are added to improve the sand compaction around the element, reducing the energy of the arc on operation. The Fuse Link body material may also be of a higher grade material, and the end connections may employ a solid metal construction or be assembled using higher temperature solders.}