Logic Gate Simulator Online

Try:
Gates
Wiring
I/O
Memory
Arithmetic
Plexers
Displays
TTL ICs
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About This Logic Gate Simulator

This free online logic gate simulator lets you design and test digital circuits directly in your browser. Inspired by Logisim, it provides a modern web-based alternative with no Java installation required. Build circuits with 53 component types across 8 categories, auto-generate truth tables and Karnaugh maps, minimize Boolean expressions with the Quine-McCluskey algorithm, and visualize signal timing.

Components

Gates: AND, OR, NOT, NAND, NOR, XOR, XNOR, Buffer — all with configurable input count.

Memory: SR, D, JK, and T flip-flops (edge-triggered with async clear), 4-bit register, 4-bit binary counter with enable and overflow.

Arithmetic & Plexers: Full adder, subtractor, comparator, 2:1 MUX, 1:2 DEMUX, 2:4 decoder.

Displays: 7-segment display, hex display with auto-decode, 8-bit LED bar, hex keypad, TTY text terminal.

TTL 7400 Series: 7400 (NAND), 7402 (NOR), 7404 (NOT), 7408 (AND), 7432 (OR), 7486 (XOR), 7474 (Dual D-FF), 7447 (BCD-to-7-seg), 74138 (3:8 decoder) — all with accurate DIP pin layouts.

Analysis Tools

Truth Tables: Click Analyze to enumerate all 2n input combinations (up to 8 inputs) and see outputs for every combination.

Boolean Expressions: Automatically extract Sum of Products (SOP) from truth tables, then minimize using the Quine-McCluskey algorithm to find the simplest equivalent expression.

Karnaugh Maps: Visual K-map display for 2, 3, or 4 variable circuits with Gray code ordering.

Timing Diagrams: Record signal changes over time. Start a clock, toggle inputs, and watch waveforms update in real-time with color-coded HIGH/LOW/unknown states.

Expression → Circuit: Type a Boolean expression like A·B + ¬C and the simulator generates the corresponding gate circuit automatically.

Frequently Asked Questions

Is this a replacement for Logisim?

It covers the most commonly used Logisim features — gates, flip-flops, truth tables, K-maps, subcircuits — in a modern browser-based interface. No Java required. Advanced features like VHDL simulation and FPGA export are not yet supported.

How many inputs can I analyze?

Truth table generation supports up to 8 inputs (256 rows). Karnaugh maps are available for 2, 3, or 4 variables. The Quine-McCluskey minimizer works for any number of inputs.

Can I save my circuits?

Yes. Save as JSON file, export as PNG or SVG image, or share via URL. Circuits are encoded in the URL hash so anyone with the link sees your exact design.

What are subcircuits?

Subcircuits let you build a circuit (e.g., a half adder), save it, then reuse it as a single component in a larger design. Double-click a subcircuit to drill into its internal logic. This enables hierarchical design — build an ALU from adders, which are built from gates.

What do the TTL ICs simulate?

9 real-world 7400-series TTL ICs with accurate DIP pin layouts: 7400 (quad NAND), 7402 (quad NOR), 7404 (hex inverter), 7408 (quad AND), 7432 (quad OR), 7486 (quad XOR), 7474 (dual D flip-flop with active-low set/clear), 7447 (BCD to 7-segment decoder), and 74138 (3-to-8 line decoder).