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.
Alliance CAD System is a set of EDA tools and portable cell libraries for VLSI design. It covers a wide range of the standard design flow (from VHDL up to layout). It includes a VHDL simulator, RTL synthesis tools, place and route tools, netlist extractor, DRC, and a layout editor.
Easy Funktion is 2D function plotter software with an equation solver. It has an office-like GUI frontend and features a built-in pocket calculator, calculating with complex numbers (with special extensions for electronics, e.g. capacitor/inductor impedance), a function to export to spreadsheet software, and an advanced formula editor with automatic formatting.
XCircuit is a UNIX/X11 program for drawing publishable-quality electrical circuit schematic diagrams and related figures, and producing circuit netlists through schematic capture. XCircuit regards circuits as inherently hierarchical, and writes both hierarchical PostScript output and hierarchical SPICE netlists. Circuit components are saved in and retrieved from libraries which are fully editable. XCircuit does not separate artistic expression from circuit drawing; it maintains flexiblity in style without compromising the power of schematic capture.
Platform Independent Petri Net Editor (PIPE) creates and analyses Petri Nets quickly, efficiently, and effectively. A key design feature is the modular approach adopted for analysis, enabling new modules to be written easily and powerfully, using built-in data layer methods for standard calculations. Six analysis modules are provided, including Invariant Analysis, State-Space Analysis (deadlock, etc.), and Simulation Analysis and Classification. PIPE adheres to the XML Petri net standard (PNML). The file format for saving and loading Petri Nets is extensible through the use of XSLT, the default being PNML.
Ngspice is a mixed-level/mixed-signal circuit simulator based on three open source software packages: Spice3f5, Cider1b1, and Xspice. Spice3 is the most famous and widely used circuit simulator. Cider is mixed-level simulator that includes Spice3f5 and adds DSIM, a device simulator. Cider couples the circuit level simulator to the device simulator to provide greater simulation accuracy (at the expense of greater simulation time). Xspice is an extension to Spice3 that provides code modeling support and simulation of digital components through an embedded event driven algorithm.
ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.