These pages describe some key concepts about validation or reliability of electronic design. Pages are based on designer or responsible of operating units specific actions:

• Understand: basic concepts, maths and demonstrations
• Measure: How to correctly analyse on-field measurements.
• Prove: How to ensure a given design is good enough?
• Predict: What to expect from measurements & datasheets?
• Compute: Open - only - software described, guides.

The context is a machine which can be operating for more than 15 years (up to 25 years), where reliability is a key parameter. Some radiation tests also requires some clear statement about results obtained during a qualification process.

Reliability is the probability that a component, subassembly, instrument, or system will perform its specified function for a specified period of time under specified environmental and use conditions.

Mathematical Reliability function is commonly described as: probability of one unit surviving until a certain time.
(It can be an exponential shape curve when failures are distributed with a fixed over time given MTBF. When starting, all units are safe, and then probability =1. when x-axis grows, probability goes to 0, since all units will eventually fail).