Reliability of a System with n Parallel and Not Identical Elements with Constant Failure Rates

Reliability models based on Marcov chain (Except queuing systems) have extensive application in calculate the reliability of electrical and electronically devices. In this article we consider a system with fl parallel and not necessary identical elements with constant failure rates (Failure rates had exponential distribution). The system works until entire elements fail. The elements are not repairable and the system could not come back to previous states. At the end, the system parameters like MTTF, are calculated and a numerical example with three parallel and not identical elements is solved.