Build. Simulate.
Understand.
Draw schematics, press run, and watch real electricity move through your circuit. An interactive electronics lab inside your browser — free, fast, and no install required.
Instant interactive circuits
Try pre-built circuits
555 Timer LED Blinker
Classic square-wave pulse generator with frequency control and output scope.
RC Low-Pass Filter
Capacitor charging curve demonstrating RC time constants and cut-off response.
Voltage Divider Network
Two-resistor divider illustrating Ohm’s law, node voltages and loaded currents.
Transistor Saturation Switch
BJT NPN transistor driven into saturation to switch high-current loads.
Built like a real laboratory instrument
CircuitSimulate is powered by authentic Modified Nodal Analysis — not cartoon animations.
Real analysis, not a cartoon
Modified Nodal Analysis (MNA) runs DC, transient and AC sweeps — the same rigorous math SPICE uses. Every readout is solved.
See electricity moving
Current animates along actual conductive paths. Nodes color by solved voltage and LEDs glow with real forward current.
100% in your browser
Runs locally in a Web Worker. Fast, works offline, zero installs, and your circuits stay completely private on your device.
Multimeter & Oscilloscope
Drop voltage/current probes or a 2-channel virtual oscilloscope onto any node to inspect real-time waveforms with Volt/Div and Time/Div.
Four steps to a working circuit
Simple enough for beginners, precise enough for engineers.
- 01
Place
Drag parts from the palette onto a snapping grid (touch or mouse).
- 02
Wire
Tap terminal to terminal — wires route orthogonally and snap cleanly.
- 03
Run
Choose DC, transient or AC sweeps. Solver runs locally in real-time.
- 04
Read
Watch current flow, inspect node voltages, or scope detailed waveforms.
Ready to simulate?
Open a blank canvas with zero setup. No account, no download, 100% free.