Systems such as satellites, airplanes, cars and air traffic controls are becoming more complex and/or highly integrated. These systems integrate several technologies inside themselves, and must be able to work in very demanding environments, sometimes with few or none maintenance services due to their severe conditions of work. To survive such severe work conditions, the systems must present high levels of reliability, which are achieved through different approaches, processes, etc. These unfold in many: levels of aggregation (systems, subsystems, equipments, components, etc.), phases of their lifecycles (conception, design, manufacturing, assembly, integration, tests, operation, etc.), environments (land, sea, air, space, etc.), types of components/applications/experiences/technological communities (nuclear, aerospace, military, automotive, medical, commercial, etc.), leaded by the widespread use of semiconductors. So, the aim of this work is to analyze some semiconductors by the Handbook MILHDBK-217 FN2 to improve the reliability of aerospace and automotive electronic equipments. To do that, this work: 1) summarizes the applicable methods, tools, components, etc., of the Handbook MIL-HDBK-217 NF2; 2) selects some semiconductors such as diodes of low frequency for power rectifiers and voltage regulators; 3) analyze their fault rates; and 4) discusses its factors, to improve the reliability of aerospace and automotive electronic equipments.