Ktechlab

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating...

The Quite Universal Circuit Simulator (QUCS) is an integrated circuit simulator allowing the simulation and graphical presentation of results of large-signal, small-signal and noise behavior in circuits.

LTspice IV is a high performance Spice III simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators.

TINA Design Suite is a powerful circuit simulation package for analyzing, designing, and real time testing of analog, digital, VHDL, MCU, SMPS, RF, communication, optoelectronic and mixed electronic circuits...

Sketch, simulate, and share your circuits, entirely in your browser -- no install required. Easy schematic capture and powerful SPICE-like, mixed-mode circuit simulation helps EE students, electronics...

PartSim is a free and full-featured SPICE circuit simulator that runs directly in your browser. PartSim schematic editor runs in your browser using javascript and does not require the use …

Ngspice is a mixed-level/mixed-signal circuit simulator. Its code is based on three open source software packages: Spice3f5, Cider1b1 and Xspice. Ngspice is part of gEDA project, a full GPL'd suite …

circuits.io is an in-your-browser circuit design tool, that makes it fun and easy to design, share and produce electronic circuits.

SIMetrix/SIMPLIS enables engineers to design and simulate switching power electronics systems

Cadence® Pspice® is a full-featured, native analog and mixed-signal circuit simulator. The demo version limits the number of nodes (and other features?) available.