Abstract :
In designing commercial equipment destined for sale in a very competitive market, where cost is a keynote, the engineering approach adopted towards achieving reliability approach adopted from that for equipment where cost assumes secondary importance. The approach used in military equipment design cannot be employed as criteria for reliability here, since the majority of components available to the designer of such equipment have unknown life characteristics. The probability of failure of a device is the product of the individual life expectancies of all components, hence the overall reliability is considerably worse than that of the weakest component. The mathematical computation of a commercial equipment´s reliability is not usually attempted by the designer, due to the lack of information available in respect to the life expectancy of most of the components used.
