NGspice is a popular free SPICE simulator based on Berkeley Spice 3, and allows detailed circuit simulations at the transistor level. The CppSim framework includes NGspice as a separate simulator from CppSim and VppSim, but users can utilize Sue2 as a schematic editor and CppSimView as a waveform viewer. As such, NGspice provides a complementary simulator to CppSim and VppSim which is useful when detailed transistor simulations are required and significantly slower simulation speed is acceptable.

By including NGspice within the CppSim framework, a rich simulation environment is achieved which allows users to simulate a broad span of circuits and systems ranging from smaller transistor level circuits (NGspice) to large, complex mixed-signal systems (CppSim and VppSim). By sharing the same schematic editor, waveform viewer, and Python, Matlab®, and Octave support functions, users can avoid a difficult learning curve when transitioning between different simulators. Also, NGspice can serve as a convenient tool to help determine the key behavior and parameters for higher level CppSim models corresponding to transistor level circuits which cannot be directly run in CppSim or VppSim.

Just as with CppSim and VppSim, users can easily share NGspice simulation schematics and control files using the Import and Export tools provided in the CppSim framework. As such, NGspice within the CppSim framework provides a convenient environment for educational purposes since instructors can easily create custom libraries that are shared with the students for given homework and project assignments.

Finally, it is important to note that the Windows download for the CppSim Version 5 package automatically includes NGspice. For documentation on using NGspice within the CppSim framework, click on the Manuals page navigation button and look at the various PDF files available within the "Making Use of NGspice" section.