KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
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.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM