Cisco Packet Tracer - Download Cisco Packet Tracer, an innovative network simulation and visualization tool used by Cisco Networking Academy students and instructors.
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.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
GNS3 - GNS3 is a graphical network simulator that allows simulation of complex networks.
Pspice - OrCAD PSpice technology provides the best, high-performance circuit simulation to analyze and refine your circuits, components, and parameters before committing to layout and fabrication