Logisim - Logisim is an educational tool for designing and simulating digital logic circuits.
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
BOOLR - Open-source digital logic simulator
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Digital - A simulator for digital circuits.
LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.