CircuitJS1

CircuitJS1 is a browser-based electronics simulator that turns a schematic into a moving picture of voltage and current. It offers sample circuits and component editing, making it a handy place to poke at an idea before reaching for a physical breadboard.

What is CircuitJS1?

CircuitJS1 puts the behavior of a circuit on display instead of hiding it behind a calculation. The destination describes an opening LRC schematic where color marks positive and negative voltage and little yellow dots make current visible. From there, the stated workflow is hands-on: choose an example, click a switch, or edit a component and watch the circuit respond. That makes it especially inviting for questions that are easier to ask with a moving diagram than a formula alone. The project’s own materials credit Paul Falstad’s original with Iain Sharp’s JavaScript conversion, and it is released as free software. A TU Berlin teaching resource separately documents its use for circuit-building and virtual measurements. This review did not run a simulation, so consider the site a clear invitation to experiment rather than a verified instrument report.

What you can do there

• Try sample circuits
• Edit circuit components
• Observe simulated current and voltage

Why we picked it

Its value is immediate and specific: circuit behavior is rendered in a way that gives voltage and current a visible presence. Sample circuits and editable parts offer a productive route from curiosity to a small, testable change.

How to get the most from it

Begin with one of the supplied examples and identify a single visible effect before changing anything. Then alter one component or switch at a time, compare the display, and keep a note of what changed before moving to a more complex circuit.

Good to know

No live circuit or control was used in this review, so simulation accuracy and saved-result behavior remain unverified. Accessibility, keyboard and touch support, motion, privacy, ads, popups, downloads, and device behavior were not tested.

Who made it, and when?

Paul Falstad is the credited creator or organization.