KiCad

            
            Electronic schematic and PCB design software

Kicad is a suite of programs for the creation of printed circuit boards.It includes a schematic editor, a PCB layout tool, support tools and a 3D viewer to display a finished & fully populated PCB.

Kicad is made up of 5 main components:

* kicad - project manager
* eeschema - schematic editor
* pcbnew - PCB editor
* gerbview - GERBER viewer
* cvpcb - footprint selector for components

Libraries:

* Both eeschema and pcbnew have library managers and editors for their   components and footprints
* You can easily create, edit, delete and exchange library items
* Documentation files can be associated with components, footprints and key   words, allowing a fast search by function
* Very large libraries are available for schematic components and footprints
* Most components have corresponding 3D models