DWSIM - DWSIM is an open-source CAPE-OPEN compliant chemical process simulator for Windows and Linux.
Circuit Simulator - Animated electronic circuit simulator using ideal components to visualize voltage and current.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.
CHEMCAD - We equip chemical engineers with integrated and intuitive process simulation software to tackle projects large and small. Discover how CHEMCAD can help you design, analyze and measure simple and complex processes like never before.
Solve Elec - Solve Elec is a free educational program to draw and analyze electrical circuits.