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.
Circuit Tree - Design and order Boards in Minutes
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
Circuit Simulator - Animated electronic circuit simulator using ideal components to visualize voltage and current.
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
CircuitLab - Sketch, simulate, and share your circuits, entirely in your browser -- no install required.