a free and powerful circuit simulator

Frequently Asked Questions

  • How should I speak the word Qucs?
    The correct pronunciation is kjuks.
  • What is the best way to get started with QucsStudio?
    1) Watch the videos on this homepage.
    2) Read the program help (F1 key) and the tutorial by Gunthard Kraus.
    3) Test the example schematics from this homepage.
    4) Modify the examples according to your needs.
  • Are there mailing lists, newsletters, forums etc about QucsStudio?
    Unfortunately, none of these exist. I don't have the time to create and to maintain them. If you can help here, it will be appreciated very much! However, reading the help of the application and studying the examples from this homepage should answer most of the questions.
  • Why are there two different projects: Qucs and QucsStudio?
    This situation isn't nice indeed. But at some point it wasn't possible anymore to reach an agreement about future developments. That's why I left the Qucs project. After some time I went on programming on my own and QucsStudio was born.
  • What are the differences between Qucs, Qucs-S and QucsStudio?
    Qucs is the original project, which all others based on. The program is open-source and available for Linux, Windows and MacOS. But it's now rarely updated, so very few progress can be expected only.
    Qucs-S is a Qucs fork. It's open-source and available for Linux and Windows. The graphical interface supports the simulators Qucs, Ngspice, XYCE and SpiceOpus. Again, updates are to be expected rarely.
    QucsStudio is a Qucs fork that stems from the original project founder. It's freely available for Windows and not open-source. But it offers by far the most features and is updated regularly.
    fREEDA is another open-source simulator that uses the graphical user interface of Qucs. The last update of this project was in November 2010.
  • How does the future of QucsStudio look like?
    QucsStudio will continue to be freely available. Neither a commercial nor an open-source version is planned.
  • Why does it take so long until a new version is released?
    QucsStudio is a purely private project. Thus, there's not much time for the development. Unfortunately, support by users is very rare, too. Any help will speed up the progress!
  • On Windows 10, component models written in C++ or VerilogA don't work. The simulation stops with the message:
    ERROR in 'X1': Cannot load library 'name.va'.

    For security reasons, the execution of the DLL file is prohibited. This can be resolved by the following procedure:
    Control Panel → System and Security → System → advanced system setting → Environment Variables
    There the project folder has to be added to the variable 'Path', i.e. 'HOME\.qucs'.