Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
OrCAD - OrCAD is a great tool for creating electronic designs that sell.
PADS PCB Design - Best-in-class PCB design tools at unbeatable prices
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.
Proteus - Proteus - Proteus is a great electrical suite for circuit simulation purposes. You can simulate a single processor or multiple ones at the same time. The application is a great alternative for Virtual System Modelling.