# Resistor Tolerance Analysis

> Sample resistor tolerances and inspect the spread of a DC node voltage. Run a seeded Monte Carlo analysis on up to eight resistors in a SPICE netlist. Inspect nominal, minimum, maximum and mean output voltage.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://ohmforgecomponenttolerance.usefulweb.site/ (interactive tool at https://ohmforgecomponenttolerance.usefulweb.site/tool)
- JSON API: POST https://ohmforgecomponenttolerance.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://ohmforgecomponenttolerance.usefulweb.site/api/v1/tool)
- OpenAPI: https://ohmforgecomponenttolerance.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://ohmforgecomponenttolerance.usefulweb.site/mcp - tool `ohmforge_component_tolerance`

## Inputs
- netlist (textarea): SPICE netlist
- node (text): Output node
- tolerances (textarea): Resistor name, tolerance (%)
- runs (number): Samples
- seed (number): Random seed

## Method
- Each selected resistor is sampled independently from a uniform distribution over its nominal value plus or minus the given tolerance.
- Each sample runs a DC operating point; failed samples are counted and excluded. The seed makes the results repeatable.

## Limits
- A teaching-grade DC simulation and sampled spread, not guaranteed worst-case bounds or a substitute for datasheet and bench verification.