Littelfuse L25S400 - L25S-High-Speed-Fuse - Designed to protect today’s equipment and systems, Littelfuse semiconductor fuses are manufactured with Littelfuse-developed technology that sets tomorrow’s standards for accuracy, consistent quality, reliability, and predictable performance. By using advanced metallurgical, polymer, and materials research; mathematical modeling, and computerized statistical analysis; Littelfuse engineers have redefined “State-of-the-Art.” - Applications-Designed specifically for supplementary protection of semiconducting devices such as silicon controlled rectifiers (SCR’s), diodes, thyristors, triacs, transistors, and similar solid-state devices. These devices are used in power equipment including variable speed drives, power rectifiers, UPS systems, DC power supplies, and in a wide range of electronic equipment. May be used wherever extremely fast-acting, current-limiting fuses with no time delay are required. Safety - 200,000 A.I.R. — Reliable interruption of all overcurrents up to 200,000 amperes . . . meets present and future system requirements. (Note: L15S series has 100,000 A.I.R.)-Extremely Current Limiting — Low I2t and peak let-through currents meet most semiconductor requirements.UL Recognized — Littelfuse semiconductor fuses are recognized under the components program of Underwriters Laboratories, Inc., and carry the mark. UL Recognized semiconductor fuses may be used to provide supplementary protection in UL listed equipment.-Safety-Low Watt Losses — Means less heating and power consumption in circuit.-Controlled Transient Overvoltages — All circuits are subject to transient overvoltages during fault current interruption. These transient overvoltages (arc voltages) start when fuse links melt or circuit breaker contacts part, and subside when circuit is interrupted. Semiconductors are very sensitive to overvoltages. Littelfuse semiconductor fuse designs keep transient overvoltages to low levels and help reduce semiconductor failure.