ng-spice: Ngspice (circuit simulator) ng-spice: ng-spice: Ngspice is a mixed-level/mixed-signal circuit simulator. Its ng-spice: code is based on three open source software packages: Spice3f5, ng-spice: Cider1b1 and Xspice. Ngspice is part of gEDA project, a full ng-spice: GPL'd suite of Electronic Design Automation tools. ng-spice: ng-spice: ng-spice: ng-spice: ng-spice: