Qucs-S: Quite universal circuit simulator with SPICE

About Qucs-S

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

Donation

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

Build instructions

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.

Dependencies

Qucs-S requires Qt6 libraries including QtCharts, CMake, flex, bison, gperf, and dos2unix as compile time dependencies. Install these packages using the package manager of your distribution before compiling Qucs-S. Ngspice is not required at compile time, but it is required as runtime dependency to run the simulation.

Here are some examples for the popular Linux distributions.

Ubuntu or Debian

sudo apt-get install ngspice build-essential git cmake flex bison gperf dos2unix
sudo apt-get install qt6-base-dev qt6-tools-dev qt6-tools-dev-tools libglx-dev linguist-qt6 
sudo apt-get install qt6-l10n-tools libqt6svg6-dev libgl1-mesa-dev qt6-charts-dev libqt6opengl6-dev

Fedora

sudo dnf install gcc-c++ cmake git flex bison gperf dos2unix ngspice
sudo dnf install qt6-qtbase-devel cmake qt6-qtsvg-devel qt6-qttools-devel qt6-qtcharts-devel 

Compiling

After installing the dependecies, 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

Since the v25.1.0 the Qucs-S will be configured with Qt6 by default. Substutute the /your_install_prefix/ as 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.

Qt5/Qt6 support

Qt5 support has been dropped since v25.1.0. Only Qt6 libraries are supported. Set the WITH_QT6=ON cmake flag if compiling the Qucs-S versions before v25.1.0

Running

Then run qucs-s executable to launch the application:

cd /your_installation prefix/bin
./qucs-s

clangd LSP support

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.