Getting to know simulation - Part11 - Monte Carlo

To best illustrate the usefulness of the monte-carlo simulation, let’s use a voltage divider as example.

Run Transient simulation and get:

So this is a perfect voltage divider. But we all knows that resistor has tolerance, let’s say each of R1, R2 has 1% tolerance. We should factor this in by running Monte Carlo simulation and see what are we dealing with.

Enter 1% as the resistor tolerance.

Tick “Enable multi-step” to enable Monte-Carlo analysis

Set number of runs to 100

Re-run the transient simulation to see gain statistic of  divider made of 2 pieces of 1% resistor.

With resistor tolerance of 1%, the voltage divider will give an error of ~-0.9% to ~+1%. Use of Monte-Carlo simulation will ease such analysis. If your application cannot tolerate such variance, then resistors with better tolerance are needed.