open-electronic

Open the simulators

Browser-based electronics simulators and calculators for engineers. No install, no sign-up, nothing sent to a server: every formula runs in your browser.

Aimed at ESP32 and hobby-electronics work, so 3.3 V is the default supply everywhere unless the part genuinely needs something else.

What it does

Pick a simulator from the list on the left, change a value, and the answer updates instantly. Most pages drive a live oscilloscope so you can see the waveform, not just a number.

• Real formulas. Every page implements the actual maths, cited in a "the maths behind this page" panel at the bottom. Nothing is approximated for convenience.
• Live oscilloscope. Shared across every page. Scroll or pinch to zoom the time base, drag to pan, adjust trace thickness and volts per division, toggle channels.
• Engineering notation. Type 4k7, 100n or 2.2 uF into any field and it parses.
• Honest warnings. When you leave the region where a model holds, a transistor out of saturation, a converter in discontinuous conduction, a GPIO over its current limit, the page says so instead of quietly printing an unphysical number.

See SIMULATORS.md for the full catalogue and the formula behind each one.

Running it locally

Requires Node and pnpm.

git clone https://github.com/HamzaYslmn/open-electronic.git
cd open-electronic/web
pnpm install
pnpm dev

Then open http://localhost:5173.

pnpm test     # run the engine tests
pnpm build    # type-check and produce a production build

How it is put together

web/src/
  engine/   pure TypeScript maths, no React, one module per topic plus its tests
  ui/       shared components: the oscilloscope, sliders, readout tiles, page layout
  sims/     one file per simulator
  catalog.ts  the registry that drives the routes, the sidebar and the home page

The maths is kept completely separate from the interface. That is what makes it testable: the engine is plain functions over numbers, so every formula has unit tests asserting it against textbook values rather than against itself.

Deployment

Pushing to main runs the Pages workflow, which installs, runs the tests, builds, and publishes to GitHub Pages. A failing test blocks the deploy, so the live site never has a broken formula on it.

To enable it on a fork: Settings, Pages, Source, GitHub Actions. If your repository has a different name, change REPO_BASE in web/vite.config.ts to match, since Pages serves the site from a subpath.

Contributing

Adding a simulator is three steps:

1. Write web/src/engine/<topic>.ts with the formulas, plus <topic>.test.ts.
2. Write web/src/sims/<id>.tsx using the shared components.
3. Set that entry's status to 'ready' in web/src/catalog.ts and attach its import.

The routes, sidebar and home page pick it up automatically.

Licence

MIT.