Electric - VLSI layout package which has been open source since 1999. This package lets you do the physical design of integrated circuits in a variety of technologies. It also includes a schematic editor, physical to logical verification, interactive design rule checker, netlisting tools and other features. The source code is available. Electrical Engineering Pack for Mathematica 1.1 - a set of specialized functions tailored for specific electrical engineering tasks in addition to practical examples of how Mathematica can be applied to problems in circuit analysis, transmission line theory, and antenna analysis.
All material provided is completely open and customizable.
The company also makes Signals and Systems for Mathematica, which analyzes signals, designs filters, and performs routine signal processing operations. Electro Bits - graphics tool containing a library of several hundred electronic elements and computer symbols that employ the MacPaint function. It's used to create schematics and circuit diagrams. ExpertPCB - printed circuit board design. Its features include T-routing, design rule checking, automated documentation and variable grids.