Logisim

Logisim is a logic simulator that allows using a graphical user interface to design and simulate circuits. Released under the GNU Public License, Logisim is a free software that runs under Microsoft Windows, Mac OS X and Linux platforms. Your code is written entirely in Java. The primary developer, Carl Burch, working on Logisim since the initial development in 2001.

The software is often used by students of computer science to develop digital circuits and simulations and experiment with them. Circuits are in Logisim, developed through a graphical user interface similar to traditional drawing programs, such as can be found in many other simulators. Unlike most of the other simulators allows Logisim the user to modify the circuit for the simulation. The relatively simple surface is well suited for introductory and overview lectures. There are also design features for complex circuits such as " Subcircuits " and " wire bundle " available. Although one can also construct complete CPU implementations within Logisim, the software is primarily intended for use in the classroom. Logisim is not able to use analog components.