KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
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.
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
Circuit Tree - Design and order Boards in Minutes
Circuit Simulator - Animated electronic circuit simulator using ideal components to visualize voltage and current.
Autodesk EAGLE - Autodesk EAGLE is an electronic design automation (EDA) software.