# Spice

Run automatic SPICE simulations on subcircuits detected from KiCad schematic analysis, ...

- Repository: https://github.com/aklofas/kicad-happy (1565 stars)
- Category: Design
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add aklofas/kicad-happy --skill spice -g -a claude-code -y`
Codex: `npx skills add aklofas/kicad-happy --skill spice -g -a codex -y`
Cursor: `npx skills add aklofas/kicad-happy --skill spice -g -a cursor -y`
Gemini CLI: `npx skills add aklofas/kicad-happy --skill spice -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add aklofas/kicad-happy`

## Description

Run automatic SPICE simulations on subcircuits detected from KiCad schematic analysis, validates filter frequencies, divider ratios, opamp gains, LC resonance, and crystal load capacitance. Supports ngspice, LTspice, and Xyce (auto-detected). Generates testbenches, runs batch mode, produces structured pass/warn/fail report. Use when the user asks to simulate, verify, or validate any analog subcircuit, RC filters, LC filters, voltage dividers, opamp circuits, crystal oscillators. Also for "simulate my circuit", "run spice", "verify with simulation", "check my filter cutoff", "does this divider give the right voltage", "what's the bandwidth of this opamp stage". Consider suggesting simulation during design reviews when the schematic analyzer reports simulatable subcircuits and a SPICE simulator is available.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# SPICE Simulation Skill

Automatically generates and runs SPICE testbenches for circuit subcircuits detected by the `kicad` skill's schematic analyzer. Supports ngspice, LTspice, and Xyce (auto-detected). Validates calculated values (filter frequencies, divider ratios, opamp gains) against actual simulation results and produces a structured report.

This skill inverts the typical simulation workflow: instead of requiring users to create simulation sources and configure analysis (which ~2.5% of KiCad users do), it generates targeted testbenches automatically from the analyzer's subcircuit detections.

## Related Skills

| Skill | Purpose |
|-------|---------|
| `kicad` | Schematic/PCB analysis, produces the analyzer JSON this skill consumes |
| `digikey` | Parametric specs for behavioral models, datasheet downloads |
| `mouser` | Parametric specs (secondary source), datasheet downloads |
| `lcsc` | Parametric specs (no auth needed), datasheet downloads |
| `element14` | Parametric specs (international), datasheet downloads |
| `emc` | EMC pre-compliance, uses this skill's simulator infrastructure for SPICE-enhanced PDN impedance and EMI filter analysis |

**Handoff guidance:** The `kicad` skill's `analyze_schematic.py` produces the analysis JSON with subcircuit detections in the flat `findings[]` array (filtered by `detector` field). This skill reads that JSON, generates SPICE testbenches for simulatable subcircuits, runs the detected simulator (ngspice/LTspice/Xyce), and produces a structured verification report. Always run the schematic analyzer first. During a design review, run simulation after the analyzer and before writing the final report, simulation results should appear as a verification section in the report. The `emc` skill reuses this skill's simulator backend for SPICE-enhanced PDN impedance and EMI filter insertion loss checks, when ngspice is available, the EMC skill's `--spice-enhanced` flag activates these checks automatically.

The rest: https://github.com/aklofas/kicad-happy/blob/HEAD/skills/spice/SKILL.md