Igor Vizec (2010) Analysis of standards used for reliability estimation of electronic components. EngD thesis.
Abstract
There are a lot of different electronic circuits we use in everyday life. Each of them has their own intended usage and are used in different ways in different environments. Some circuits will be exposed to bad weather conditions, while others will be safely placed in controlled environment, e. g. in an office. Each developer and user is interested in the expected life span of the device. In order to determine the expected life span, we need to be aware of the environment where the device will be performing and the amount of time it will be working. This data is crucial for choosing the components of a device. Therefore, standards which help us to correctly choose the components have been established on the basis of the previously defined intended use and work environment of the device. My thesis presents the reliability theory, where basic concepts of reliability are discussed. Further on, three most commonly used standards are described (MIL-HDBK-217F, IEC 63280 and Telcordia SR-332). Advantages and disadvantages of the standards are first presented in theory and later applied on a real electronic circuit which is used in telecommunications. Automatic calculations of failure rates of the mentioned circuit were made with the BQR CARE tool, as well as the comparison of these results with the results obtained with calculations according to the equations defined in the standards. It is shown that comparison of components according to standards demands a lot of attention and it does not suffice to check the final results as they can vary according to the type of the used calculation. It is also important to know according to which standard the reliability analysis was done because, as the results show, there are great differences.
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