QUCS is described as «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» and is a circuit simulator in the education & reference category. There are more than 25 alternatives to QUCS for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and iPhone. The best alternative is Circuit JS, which is both free and Open Source. Other great apps like QUCS are LTspice, Circuit Simulator (CircuitJS1), Ktechlab and iCircuit.QUCS alternatives are mainly Circuit Simulators but may also be Electronic Design Automation Tools or CAD Software. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of QUCS.