Trace is a digital logic circuit simulator built with Java and Swing. Design, wire, and simulate breadboard circuits with ICs, switches, LEDs, and power rails — all on a drag-and-drop canvas.
Drop components onto the canvas and wire them up by clicking pins. The simulator ticks in real time, so LEDs light up the instant your logic resolves.
Built-in Demo Circuits
Load ready-made circuits from the Demos panel — Half Adder, Full Adder, Ripple Adder, Binary-to-Gray converter, and more. Great for learning or as a starting point.
Each demo is laid out on a real breadboard with proper power rails, IC placement, and clean wire routing. No spaghetti — wires hop across shared rows instead of looping around chips.
Supports standard 74-series ICs (7400, 7402, 7404, 7408, 7432, 7486, …) alongside switches, DIP switches, LEDs, light bars, BCD displays, 5V supplies, and ground. Pin 14 goes to the top rail, pin 7 to the bottom — just like the real thing.
Interactive Simulation
Flip switches and watch signals propagate through gates instantly. The status bar reports wire counts, component counts, and simulation state, so you always know what's on the board.
Test Mode
Switch into Test Mode to verify your circuit against a truth table. Trace — scans the board for labelled inputs and outputs, then lets you define expected H/L values for each row.
Add rows, set the expected output bits (or leave them as "don't-care"), and hit Run. Every row is driven into the circuit, the simulator settles, and each row is marked pass or fail — so you know at a glance whether your Half Adder actually adds.
Sub Circuits
Create sub-circuits for repetitive logic, reuse them across your projects, and share them with friends.