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.
  5) Ask your remaining questions in the forum.
• 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.
• The original Qucs project was released under the GNU General Public License (GPL). Does QucsStudio violate the GPL?
  No, the closed-source parts of QucsStudio are completely written and owned by the author. All programs that contain GPL code by other authors are published on this website (see download section).
• How does the future of QucsStudio look like?
  QucsStudio will continue to be freely available. An open-source version is not 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!
• I don’t want all the data to be saved in .qucs\ in the user directory. How can I change this?
  The wanted directory can be set with minus sign in the command line, e.g. running qucs.exe -“C:/projects”.
  A file link is the best way to realize this. I.e. drag’n’drop qucs.exe onto the desktop by pressing the Alt key. Then click with the right-hand mouse button onto this icon and choose Properties in the opening menu. In the appearing dialog the command line can be entered. Having done so, QucsStudio can be started with the new directory by double-clicking on this link.
• How to solve problems on Windows 10 and above?
  Usually, QucsStudio runs fine on Windows 10, but some users reported bugs like crashes when opening a project. This can be solved as follows:
  Click with the right mouse button on ~/QucsStudio/bin/qucs.exe and choose “Troubleshoot Compatibility”. It should be compatible with Windows 8. Save the setting and the problems should be solved.
• Does QucsStudio run on other operating systems than Windows?
  With the software Wine, Windows applications like QucsStudio runs on Linux, MacOS and BSD. This was successfully tested many times. 
  If simulations with microstrip components end up with an error message (about sinh function), the wrong DLLs are used. Then, start winecfg. In the Library tab add msvcp100 and msvcr100 and set them to native.
• What should I do if my question isn’t answered here?
  Please have a look into the forum. A lot of topics have already been discussed there. And of course, you can also ask your own questions.