> I think you would probably need to do multiple runs with components of varying values within their specified precision. That's called Monte Carlo analysis. I

> I think you would probably need to do multiple runs with components of varying values within their specified precision. That's called Monte Carlo analysis. It's important for standard simulation applications as well because most components are specified with certain tolerances. Your amplifier might look stable at the expected component values, but if all of your resistors are at the bottom or top of their tolerance range, it might become unstable! Commercial SPICE simulators (like HSPICE, for example) come with the option to perform this built-in. You can do Monte Carlo analysis with NGSPICE, but you have to organize the input and output yourself. > I can see evolution getting some sort of benefit by exploiting the fact that two identically specced components behave _exactly_ the same way. Something that would not happen in real life. You get pretty close with matched transistors, especially when they're on the same die. But yeah, Monte Carlo.