Logisim evolution is a free open source digital logic circuit designer and simulator application for Linux, Windows and MacOS. It comes with electronic board integration, chronogram, VHDL components and TCL/TK console. It is wrritten in java and released under GNU General Public License v3.0. It comes with pre-build huge components library with LED, SoC, TTL switches, RAM, ROM, flip-flop, plexers, Gates and more. You can download Logisim evolution via the below download link.