Qucs-S provides a fancy graphical user interface for a number of popular circuit simulation engines. Qucs-S contains instruments for schematic capture, visualization and provides differents passive and active components including device library. The following simulation kernels are supported:

• Ngspice (recommended)
• Xyce
• SpiceOpus
• Qucsator (non-spice)

See the https://ra3xdh.github.io/ for more details. Qucs-S is based on original Qucs code: https://github.com/Qucs/qucs

Qucs-S accepts donation using Boosty platform: https://boosty.to/qucs_s

Use CMake to build Qucs-S. Install all necessary dependencies: GCC, Qt, Flex, Bison and SPICE (optional). Install ngspice that is not needed for build, but serves as the simulation kernel.

sudo apt-get install ngspice build-essential git cmake qtbase5-dev qttools5-dev libqt5svg5-dev flex bison gperf dos2unix

sudo zypper install ngspice git cmake libqt5-qtbase-devel libqt5-qttools-devel libqt5-qtsvg-devel flex bison gperf dos2unix

Then clone this git repository and execute in the top directory:

git submodule init
git submodule update
mkdir builddir
cd builddir
cmake ..  -DCMAKE_INSTALL_PREFIX=/your_install_prefix/
make
make install

Where /your_install_prefix/ is desired installation directory. Substitute any desire path (for example $HOME/qucs-s) here. You may omit this option and installation steps. Default installation directory will be /usr/local if CMAKE_INSTALL_PREFIX is not defined.

Since v1.0.1 Qucs-S supports build with Qt6. Set the WITH_QT6 flag to tell CMake use the Qt6. For example use the following command sequence for Ubuntu-22.04

cmake .. -DWITH_QT6=ON -DCMAKE_INSTALL_PREFIX=/your_install_prefix/

Then run qucs-s executable to launch the application:

cd /your_installation prefix/bin
./qucs-s

Clangd looks for compile_commands.json file in parent folders of the file it processes. compile_commands.json should be generated along with other build configuration files when you run cmake as part of building routine:

mkdir builddir
cd builddir
cmake ..  -DCMAKE_INSTALL_PREFIX=/your_install_prefix/

If compile_commands.json is already there, create a symbolic link to it from project root dir:

cd project_root
ln -s ./builddir/compile_commands.json compile_commands.json

It may take some time to index files at first run. Clangd configuration is in .clangd file.