Introduction

The reliability of electronic equipment has received increasing attention during the past twenty years, as apparatus has grown more complicated and has been applied to a great variety of important tasks. Despite its current interest to the practising engineer, the study, design and evaluation of reliable systems as a professional activity has gained only limited recognition. One reason for this is undoubtedly the wide range of topics which concern the reliability engineer. These include mathematical subjects such as probability theory and statistics, practical subjects such as the characteristics of electronic components and devices and the design and construction of electronic equipment, and some physics and chemistry in the study of failure and corrosion. He may also be involved in the environmental testing of components and apparatus under a wide range of conditions. Thus an electronic engineer who is concerned with equipment reliability will encounter a variety of mathematical and scientific problems in addition to those arising from his own particular branch of engineering.