An electrical component, such as a resistor or capacitor, is usually quantified with a nominal value and a 
tolerance. That is, a resistor could be rated at 5 Ω with a tolerance of 5%; this means the resistance could vary 
between 4.75 and 5.25 Ω.

Given the number of components in a circuit and their compounded tolerances, the actual performance of a 
circuit may not necessarily match its desired performance. This is a source of risk that needs to be managed 
and mitigated.

Accordingly, electrical engineers need to analyze a circuit over all potential operating conditions.

Extreme Value Analysis (EVA) is a process in which the behavior of a circuit is simulated for every permutation
of extreme component parameters - that is, a resistor of 5 Ω ± 5% is simulated at 4.75 Ω  and 5.25 Ω, in 
combination with every permutation of extreme values for all other components (this is a type of worst case 
circuit analysis).

Given the results of an EVA, a circuit that falls out of spec may have its performance improved by replacing 
cheaper components that have a loose tolerance with higher quality components that have a tighter tolerance.

This application performs an extreme value analysis of the following circuit (the principles, however, can be 
extended to any circuit). Light hits a photodiode and generates a current. A non-inverting op-amp then 
produces a linearly proportional voltage from the photodiode current. Capacitors are ignored - hence this is a 
DC analysis.