Online circuit simulator
Simulate circuits online, right in your browser.
Draw a schematic, press run, and watch real current move through it. No install, no sign-up, nothing to configure — just an accurate electronics lab that lives in a browser tab.
What you can do
- Draw schematics by dragging parts onto a snapping grid and clicking terminal to terminal to wire them.
- Run a real DC operating point, a transient sweep over time, or an AC frequency sweep — the same modified nodal analysis SPICE uses.
- Watch current animate along the wires it actually flows through, with nodes coloured by their solved voltage.
- Probe the circuit with a two-channel oscilloscope and a multimeter reading real volts and amps.
- Everything runs in your browser tab — the solver lives in a Web Worker, so the interface stays responsive.
Questions
- Is the online circuit simulator really free?
- Yes. Every analysis — DC, transient and AC — is free with no account and no install. Your circuit stays in your browser unless you choose to share it with a link.
- Do I need to download or sign up for anything?
- No. Open the page and start building. After the first visit the app is cached, so it keeps working even with a flaky connection.
- Is this a real simulator or just an animation?
- It is a real solver. A modified-nodal-analysis engine computes node voltages and branch currents, and the on-screen animation is driven by those solved currents — not a scripted loop.
- What components can I use?
- Resistors, capacitors, inductors, diodes, LEDs, DC and AC sources, batteries, ground, and measurement probes. Browse the full set in the component library.
Open a blank canvas.
Free, browser-based, and yours to keep private.
Open the simulator