Why is RBD in parallel considered better than in series?

The reason RBD (Reliability Block Diagram) configurations in parallel are considered better than those in series is that they enhance overall system reliability. When components are arranged in parallel, the failure of one component does not necessarily result in system failure, as other components can continue to function independently. This redundancy ensures that the system remains operational and can meet its performance requirements even if one or more components fail.

In contrast, a series arrangement means that all components must function correctly for the system to operate. If any single component in a series configuration fails, the entire system fails, leading to reduced reliability. The parallel configuration effectively distributes the risk of failure, thereby improving the overall reliability of the system.

Choosing parallel configurations is particularly beneficial in applications where maintaining functionality is critical, as it provides a buffer against unexpected failures, thus enhancing the robustness of the system as a whole.