Falstad Circuit Simulator

What Falstad Circuit Simulator actually is

Current is drawn as moving dots along the wires, with colour showing voltage at every point. Dozens of prebuilt examples load from a menu, from a simple RC filter through op-amps and logic gates to a full 555 timer, and any component value can be changed while it runs.

Why it is worth your time

Seeing the dots slow to a crawl as they cross a resistor turns Ohm's law from a formula you memorised into something you can sit and watch happen.

Common questions

Is Falstad Circuit Simulator free?

Yes. Falstad Circuit Simulator is free and does not ask you to register or hand over an email address before you can use it.

How long does Falstad Circuit Simulator take?

One quick round, then you can leave. We file it under "A minute" — build a circuit and watch the electrons move through it.

Does Falstad Circuit Simulator work on a phone?

Falstad Circuit Simulator really wants a mouse and a wide window. It will load on a phone, but the experience is built for desktop.

What kind of site is Falstad Circuit Simulator?

We list it under Sandboxes & Simulators — small worlds that keep running without you. Seeing the dots slow to a crawl as they cross a resistor turns Ohm's law from a formula you memorised into something you can sit and watch happen.