Tolerance & Monte Carlo

Tolerance & Monte Carlo (Premium) #

Real components are never exactly their nominal value. With a Premium subscription you can give components a tolerance and let Breadpad vary them across simulation runs, so you can see how manufacturing spread affects your circuit before you build it.

This is not a separate analysis mode — tolerances are properties you set on components and observe through a transient simulation.

How it works #

  1. Edit a component (resistor, capacitor, inductor, wire, …).
  2. Set its Tolerance (e.g. ±5%). Tolerance is a Premium parameter.
  3. Run the simulation. Breadpad applies a six-sigma Gaussian distribution around the nominal value, so ~99.7% of sampled values fall within the tolerance band.

If you don’t set an explicit tolerance, Breadpad can infer one from the number of significant figures you typed for the value.

When to use it #

  • Estimate how much an output (e.g. a divider voltage or a filter cutoff) drifts with real-world parts.
  • Decide which components need tight (1%) versus loose (5–10%) tolerances.
  • Sanity-check a design’s robustness before committing to a build.

Tips #

  • Use realistic tolerances from the part’s datasheet.
  • Tighten only the components that actually move the output — leave the rest loose to keep cost down.
  • Combine with Temperature Sensitivity to see thermal and tolerance effects together.

See also #