Circuit Lab is a free interactive electrical circuit simulator rendered in 2.5D isometric view. Build circuits with batteries, resistors, LEDs, switches, capacitors, motors, fuses, and measurement tools. A real-time solver calculates voltages and currents using Modified Nodal Analysis.

The simulator uses Modified Nodal Analysis (MNA) to solve Kirchhoff's voltage and current laws for your circuit. When you close a switch or change a component value, the entire circuit is recalculated in real-time. Current flow is animated with moving dots along wires.

The lessons cover: basic LED circuits, series vs parallel resistors, voltage dividers, short circuits and fuses, switch logic (AND/OR gates), RC charging curves, ammeter placement, and a multi-loop challenge. Each lesson has hints and a validate button.

Yes. Click "Save Circuit" to store your circuit in localStorage. You can load saved circuits anytime. You can also export the board as a PNG image.

Yes, completely free. No account, no subscription, no watermark. It is one of the free browser-based tools at jasperbernaers.com.