gEDA is a suite of electronic design automation (EDA) tools. Currently, the project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout.
THUD is a register transfer level (RTL) simulation environment optimized for cycle- based designs. The design is expressed in TH, a Scheme-based hardware description language (HDL) that supports 1/0/x operators and hierarchical instantiation. THUD can be used as a library, in batch mode, or through one of its interactive interfaces.
Bartels AutoEngineer is a commercial CAD tool for electrical / computer engineers. It supports Linux, Win95/NT, DOS, OS/2, HP, DEC and Sun. Features include a schematic Editor with hierarchical design support, Forward/Backward Annotation, PCB Layout system, CAM Processor, CAM View, Integrated, object-oriented database system, User Language Compiler, utility programs for database management, foreign net list and design data import, etc. and part libraries for SCM and PCB layout
Signal Generator is a laboratory noise/sound generator which can be used to generate accurate sounds in fixed frequency, 2-channels (two frequencies going at once), a sweep-pattern, or in a specified sequence. It is useful when you need to generate a fixed sound for whatever purpose (in the laboratory, for sound effects, etc)
Pcb is a handy tool for the X Window System to design printed circuit boards. All coordinate units are 1/1000 inch. A layout consists of lines, arcs, polygons, elements (lines, pins and arcs), vias, and text information seperated into several layers. Each of them is identified by a unique name and color (if supported by your display). SMD circuits are also supported. Eight layers are supported, in addition to a silkscreen layer. Visibility of pins and SMD pads and vias is controllable. All files are 7-bit ASCII, and can be preprocessed with any Unix command that writes its results to stdout (GNU m4 is required). Zooming, unlimited undo, and unlimited redo are supported. Pcb is intended to be a simple tool without memory and time consuming features like autorouter and autoplacement. Layout related settings are saved together with the data.