Simulator
4-state logic
0, 1, Z and E on single wires and buses up to 32 bits across all 41 classic Logisim components.
Logisim online — rebuilt for the browser (no Java)
Every circuit step, explained.
Run Logisim online with the 4-state simulation engine, symbolic Logisim AI Circuit Coach, Karnaugh map analyzer, and Logisim 2.7.1 .circ import/export rebuilt in TypeScript. Ask why any pin or wire is 0, 1, E (red) or Z (blue), or get 4-stage Socratic nudges.
Logisim AI Circuit Coach & Signal Prover
Ask "why?" about any wire, and watch the proof unfold.
Select a wire, Input/Output Pin, flip-flop, or gate and ask why it has its value. The symbolic AI Coach traces the upstream drivers behind it and highlights the exact cause.
1. Where to look → 2. The pattern → 3. The logic → 4. Conclusion
"The output is E because two gates drive this wire at once: one with 0 and one with 1. Separate them with an OR gate or a tri-state buffer."
K-Map Analyzer
Truth table to circuit
Minimize with Quine-McCluskey, see the loops on a Gray-code map, then synthesize gates in one click.
Compatible
.circ import and export
Open classic Logisim 2.7.1 files in the browser, and save back for the original program.
Practice
Daily challenges
A new design or troubleshooting puzzle every day, with shareable results.
Popular references: 7-Segment Display Pins · S-R Flip-Flop · T Flip-Flop · XOR Logic Gate · Input Pin · Tunnel. Looking for a Java-free Logisim? See Logisim Online (No Java).
Runs entirely in your browser. Works offline once installed.