reliability engineering

Introduction An FMEDA (Failure Modes, Effects and Diagnostic Analysis) is the quantitative sibling of the FMEA we've written about before. Doing an FMEDA on a circuit means going through every component and asking how this fail could, and what is the effect. We then need to determine the immediate effect of the failure and the overall effect on the system We'll use one example throughout: A battery voltage monitor. A 12 V battery feeds a resistor divider R1/R2 (see figure bel

What is a Reliability Block Diagram (RDB) An RBD is a graphical diagram to qualitatively and quantitatively determine the overall reliability of a system. This helps identify the overall success or failure rate of a system in deployment. The RBD shows the essential components that contribute the success of the system. How to create one? Let's build an example! Consider a simple lightbulb circuit (Fig 1). There is a battery powering a lightbulb through a switch and a current l

Every engineered system fails eventually. Reliability engineering is the discipline of quantifying when and how often they fail, turning vague intuitions about durability into numbers you can design against. This post walks through the core terms in reliability/ safety engineering and their mathematics: the failure rate, the reliability and failure functions, the meaning of MTTF and MTBF, and how to combine component numbers up into a system-level estimate. Failure Rate The f