Assessment of system reliability in electronics

An overall concept of reliability and its application is fundamental in assessing electronic systems where such aspects as safety and availability are of prime importance. The need for, and the depth of, assessment tends to depend on the human or financial risks involved with the particular system. Appropriately, the quantification of reliability has played an important part in the current development of assessment techniques where the aim has been to assess reliabilty with a minimum of subjectiveness. In the assessment process it has been necessary to employ a combination of methods based on field experience and theoretical prediction. The synthesis of the reliability of systems in the early stages of design has become an essential part of reliability growth and understanding. The techniques involved in this process extend from the analysis of capability to the likely variation in performance of the system. When the achieved performance is compared with the required performance an overall reliability function may be expressed. Performance spectrum methods of analysis and boundary approaches require to be integrated with the availability of the appropriate reliability data. The paper describes the general approach made in this field of assessment taking particular electronic and control systems as examples.