It has been some years since I last used Qucs so I thought it was time I gave it another look.
Qucs is a free and open source circuit simulator with an entirely graphical interface, it's available for many operating systems including Windows, Linux and Mac OSX, the current version as of writing this is 0.0.17.
The user interface is quite simple to learn and use, the toolbox on the left side is where you can select your components as well as graphs, text and shapes to place in the schematic, simulation is done similar to LTSpice by placing a simulation block and then telling it to simulate, the results of the simulation can be graphed on your schematic avoiding the need for additional windows, you can use another window if you prefer it.
Qucs supports all the common simulations you'd expect, DC operating point, parameter sweep, AC and transient but it also supports digital, s-parameter, harmonic balance and optimization, the results can be displayed on a variety of graphs such as cartesian, polar, smith chart, 3D cartesian and more, this allows for quite extensive circuit analysis.
Support is also included for both VHDL and Verlog for digital simulation, another nice thing is the wide variety of transmission lines supported such as 2 and 4 terminal transmission line, coaxial, waveguides and microstrips making Qucs a very powerful simulator if you need those things.
I could go on all day about the features so I'm just going to list them.
- Variety of included component models
- Custom component models
- HICUM, BSIM2 and BSIM3 models
- Project management
- Built in design calculators
- CSV export of simulation data
Overall Qucs is a rather good simulator offering features that quite a few commercial circuit simulators cannot match, even better it's free so there is no reason not to give it a go.Qucs Website