Logic Circuit Simulator Online
A free online simulator where you build digital circuits from logic gates right in your browser — from the first wire to a working 8-bit processor. Nothing to install: open the page and start building.
What you can build in the simulator
The simulator is organized as a course of 47 levels in 4 parts. Each level is a specific circuit you build from available components and verify against a truth table:
- Basic gates. Start with a wire, then build NAND, NOT, AND, OR and XOR from logic elements.
- Arithmetic. A half adder, full adder and 8-bit adder teach the circuit to add numbers.
- Memory and time. An SR latch, D flip-flop and 8-bit register are the basis of all memory. Add a clock generator.
- Processor. An ALU, program counter and decoder — and by level 16 you assemble an 8-bit computer with assembly.
- Peripherals. A gamepad, matrix display and random generator — and your own processor runs Snake.
- Verilog and FPGA. Levels 30–47 describe circuits in Verilog; the final level exports the project to a ZIP for a real Tang Nano 9K board.
Sandbox mode lets you experiment freely: any components, clock control and assembler without checks or limits.
How to start
- Open the simulator. Go to Levels mode — the first level is waiting.
- Build a circuit. Drag components from the palette onto the canvas and connect them with wires.
- Verify and pass. Press Check (F9) — the simulator runs the circuit against the truth table and tells you what to fix.
Stuck? Press the hint button or ask the AI tutor — it analyzes your circuit and asks guiding questions.
Who it is for
The simulator suits school students learning computer science, university students, and anyone curious about how a computer really works — from silicon to code. The course is used as a basis for a school curriculum in circuitry.
Other tools
- Truth table generator — enter a Boolean formula and get the full table.
- Number base converter — convert between binary, decimal and hexadecimal.
- Knowledge library — 33 articles and 37 component datasheets on circuitry.