KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
BioWin - BioWin
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
AQUASIM - In order to support environmental scientists in finding an «adequate» model of the system...
QUCS - Qucs, briefly for Quite Universal Circuit Simulator, is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit.
DWSIM - DWSIM is an open-source CAPE-OPEN compliant chemical process simulator for Windows and Linux.