DCircuit Lab is a tool for simulating combinatorial and sequential digital circuits.

Circuits can be simulated in two ways:

1) one single step: all the outputs values are evaluated at the same time

2) step by step: outputs and gates are evaluated one step a time. This shows how each gate's output changes and how changes propagate through the circuit. This feature is very useful to understand complex circuits behavior.
At the end of eache simulation step, each gate may have a different color:

* black: gate's output unchanged during the just ended simulation step
* dark green: gate's output evaluated during the just ended simulation step
* light green: gate's output evaluated during the just ended simulation step, gate needs to be evaluated again during the next simulation step
* blue: gate needs to be evaluated during the next simulation step

At the end of the simulation, each wire's color corresponds to the digital value carried on itself: red for 1 and gray for 0 and light gray for undefined value.

If circuit contains clock inputs, it's simulation is dynamic. This means that outputs change accordingly to the clocks. During this dynamic simulation, user can change inputs values to study the circuit behavior. Once the simulation is stopped, a circuit timing chart is available.

Circuits are built using basic components, gates and flip-flops:

* input pins (three state: 1, 0, X - undefined)
* output pins
* wires
* 2 inputs and 3 inputs AND gates
* 2 inputs and 3 inputs NAND gates
* 2 inputs OR gates
* 2 inputs NOR gates
* 2 inputs XOR gates
* NOT gates
* Flip-flop RS, JK, T, D
* 4 Inputs Multiplexer
* 4 Outputs Demultiplexer
* 4 Outputs Shift Register

Many more components are planned to be added soon.

Some video tutorials are available to learn using the application. Visit the developer's site to see the video tutorials.