EEcircuit is a circuit simulator based on ngspice, and it runs inside the browser using WebAssembly technology. The input is schematic, and the output is the results of the analysis that you're doing in the simulations. You are able to plot and view the results directly in the browser using a high-performance WebGL plotting library webgl-plot, or download the data in CSV format for further analysis. Notice that your schematic and results are processed locally and always remain inside your browser and are never uploaded to the network. The focus of this implementation is rapid analysis and sharing circuit ideas and results within the VLSI and chip-design communities.
The next version of EEcircuit has been released! If you still require the old version go to gen1.EEcircuit.com.
For a user guide, go to help.EEcircuit.com.
Watch the launch presentation video 📺
The repository expects the sibling ../EEcircuit-schematic package because it is a local file dependency. Install with npm ci, run npm run check, and run npm test for the sequential headed local-Chrome suite. Video-generation tests are separate and are not included in npm test.
Deployment uses Wrangler and the Cloudflare configuration in wrangler.jsonc.
The application reads and writes EEcircuitV2 documents. V2 schematic connections are explicit: a connected wire endpoint has a terminal or junction reference, while an endpoint without a reference is electrically floating even if it shares a terminal's coordinates. Canonical saves may store a net name on one representative wire instead of repeating it on every connected segment.
EEcircuitV1 is obsolete and cannot be opened directly. When a V1 file is selected, the application offers to convert and download a separate V2 file. The converter rejects ambiguous or invalid wiring rather than changing the circuit by guessing.
The latest committed schematic and simulation setup are saved synchronously as a versioned snapshot under eecircuit-browser-project. Refreshing or reopening restores empty canvases, wires/text, project metadata, profiles and unfinished drafts, authored manual netlists, plot selections/settings, and the workspace. Plot restores Simulation because results are not saved. Camera, pointer/preview state, undo history and simulation results are excluded; exported files remain EEcircuitV2.
Invalid or unsupported snapshots and failed imports retain the saved value. Autosave pauses during recovery until an explicit successful opening or creation. Storage failures produce one notification. ?clean=true neither restores nor writes the browser project; clearing local data stops persistence before reload.
This is a selective port of EEcircuit-Next commit a8d4c6b5e958314e89886493ae60e17e643fcef8. The shared BrowserProjectPersistence controller and its transaction/lifecycle interfaces are retained. V2 capture, validation and hydration intentionally omit Next's layout, PDK/process/corners, Monte Carlo, transmission-line models/library and shared parameters, plus their session settings.
For eventual integration, retain tests/fixtures/browser-project-v2.json: Next's reader must upgrade its project with the existing V2-to-V3 converter and default newly introduced session fields before hydration. This port does not implement that reader upgrade or a merge, and does not guarantee a conflict-free future merge.
The current shared schematic package also exposes component families absent from this application. The property map allows a subset of the editor's types and the picker filters to that supported subset; this keeps dependency type checks valid without adding those features. An application history boundary prevents Undo from reaching the editor's startup blank entry after restoring or replacing a document; no history is serialized.
To learn more about SPICE netlists, refer to the ngspice manual.
EEcircuit is built on top of Ngspice, Emscripten, React, Vite, and Cloudflare Wrangler.