L50 VERY FAST-ACTING SEMICONDUCTOR 250A. Littelfuse L50S Series High-Speed Fuses are designed to protect today’s equipment and systems, and are manufactured with Littelfuse-developed technology that sets tomorrow’s standards for accuracy, consistent quality, reliability, and predictable performance. Littelfuse engineers have redefined High-Speed Fuse Technology by using advanced metallurgical, polymer, and materials research, mathematical modeling, and computerized statistical analysis. 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 AC: 200 kAIC DC: 20 kAIC — Reliable interruption of all overcurrents meets present and future system requirements. Extremely Current Limiting — Low I2t and peak let-through currents meet most semiconductor requirements. UL Recognized — High-speed 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 high-speed fuse designs keep transient overvoltages to low levels and help reduce semiconductor failure.