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.. 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.