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

Gnucap is described as 'The GNU Circuit Analysis Package, a modern post-spice circuit simulator with several advantages over Spice derivatives' and is a circuit simulator in the education & reference category. There are four alternatives to Gnucap for Mac, Windows and Linux. The best Gnucap alternative is Ngspice, which is both free and Open Source. Other great apps like Gnucap are McCAD 3SPICE, MacSpice and PrimeSim HSPICE.
Ngspice is a mixed-level/mixed-signal circuit simulator. Its code is based on three open source software packages: Spice3f5, Cider1b1 and Xspice. Ngspice is part of gEDA project, a full GPL'd suite of Electronic Design Automation tools.

McCAD 3-SPICE is based on the latest version (3F5) of Berkeley's SPICE 3 and permits interactive mixed mode circuit simulation. It was developed specifically to take advantage of the processing speeds available thus permitting extremely fast simulations.

Simulates and analyses electronic circuits that can range in complexity from a single resistor to an integrated circuit comprising tens-of-thousands of devices.


As IC geometries continue to shrink, the need for an accurate circuit simulator is critical. Designers require a highly accurate circuit simulator to precisely predict the timing, power consumption, functionality, and yield of their designs.