# MOSFET IV Characterization Visualizer

Interactive web-based visualizer for MOSFET IV curves. Plot Drain Current (Id) vs Drain-to-Source Voltage (Vds) with multiple gate voltage (Vgs) sweeps, overlay data from different devices, compute saturation boundaries, and extract device parameters.

**Source:** [adom-inc/mosfet-visualizer](https://github.com/adom-inc/mosfet-visualizer)

## Installation

Clone from GitHub and start the server. Idempotent — safe to run multiple times.

```bash
INSTALL_DIR="/home/adom/mosfet-visualizer"

if [ -d "$INSTALL_DIR/.git" ]; then
  echo "[mosfet-visualizer] Updating..."
  cd "$INSTALL_DIR" && git pull origin main
else
  echo "[mosfet-visualizer] Installing..."
  git clone https://github.com/adom-inc/mosfet-visualizer.git "$INSTALL_DIR"
fi

cd "$INSTALL_DIR" && npm install --production
bash "$INSTALL_DIR/start-mosfet-visualizer.sh"
```

Verify: `curl -sf http://127.0.0.1:8778/health`

The service auto-starts via `service.json` if placed in `$GALLIA_DIR/services/`. No CLI binary needed — Claude uses the HTTP API directly.

## Features

- **Multiple Vgs sweep curves** with per-sweep color coding
- **Device overlay** — compare multiple MOSFETs on the same chart
- **Custom legend** — eyeball toggle per device and per sweep, sweep count badges
- **Saturation boundary detection** — compute the linear/saturation region boundary via knee detection algorithm
- **Parameter extraction** — threshold voltage (Vth), on-resistance (Rds_on)
- **Linear/Log scale toggle** — essential for subthreshold characterization
- **Crosshair cursor** with hover tooltip showing exact Vds, Id, Vgs values
- **Export** — PNG, SVG, CSV, JSON
- **CSV import** — drag-and-drop curve tracer CSV files directly onto the chart
- **Real-time API control** — WebSocket pushes all state changes to the frontend instantly
- **Shot log** — monitor all API calls with timestamps and durations

## Data Formats

### JSON Sweeps
```json
{
  "action": "plot",
  "device": { "id": "IRF540N", "name": "IRF540N", "type": "NMOS" },
  "sweeps": [
    { "vgs": 4.0, "data": [{ "vds": 0, "id": 0 }, { "vds": 5, "id": 0.5 }] }
  ]
}
```

### Curve Tracer CSV
Column triplets per sweep: `VN (V), IN (A), RN (Ohm)` — auto-detected from headers.

## AI Prompts

| Prompt | What it does |
|--------|-------------|
| "Install the MOSFET IV visualizer" | Clones repo, installs deps, starts server |
| "Plot my MOSFET IV curves from this CSV file" | Reads CSV, sends to visualizer |
| "Show me the MOSFET visualizer with sample data" | Starts server, loads demo, opens panel |
| "Compute the saturation boundary curve" | Runs knee finder, draws red dashed parabola |
| "What's the threshold voltage?" | Analyzes data, extracts Vth |
| "Switch to log scale" | Toggles Y-axis to log10 |
| "Overlay my BSS138 data on the IRF540N" | Adds second device for comparison |

## Keyboard Shortcuts

| Key | Action |
|-----|--------|
| L | Toggle linear/log scale |
| K | Compute/clear saturation curve |
| S | Load sample data |
| R | Reset zoom |

## Architecture

- **Server:** Node.js HTTP + WebSocket (port 8778)
- **Frontend:** Self-contained HTML with Plotly.js
- **Brand:** Adom dark theme (teal #00b8b0)
- **No CLI needed** — Claude reads the skill and uses `curl` to control the API