Falstad CircuitJS

Falstad CircuitJS provides an interactive environment for creating and analyzing electronic circuits directly in a web browser. Users can place components such as resistors, capacitors, inductors, sources, and logic devices, then observe voltage, current, and waveform behavior in real time as the simulation runs. The interface supports dragging, connecting, and configuring elements with immediate visual feedback, making it suitable for exploring circuit operation and troubleshooting designs.

The tool is aimed at students, educators, hobbyists, and engineers who need a quick way to prototype and test circuit ideas without installing dedicated software. Its web‑based nature allows access on any platform with a modern browser, and the core implementation includes support for macOS environments. Because it runs entirely client‑side, no external services are required, and the simulation can be paused, stepped, or reset at any point.

Distinctive aspects include a visual, animated representation of signals flowing through the schematic and a library of predefined example circuits that illustrate common concepts. The simulator is considered stable and ready for regular use in educational settings and informal design work.