Ngspice is a general-purpose circuit simulator program.
It implements three classes of analysis:
- Nonlinear DC analyses
- Nonlinear Transient analyses
- Linear AC analyses
Ngspice implements the usual circuits elements, like resistors, capacitors, inductors (single or mutual), transmission lines and a growing number of semiconductor devices like diodes, bipolar transistors, mosfets (both bulk and SOI), mesfets, jfet and HFET. Ngspice implements the EKV model but it cannot be distributed with the package since its license does not allow to redistribute EKV source code.
Ngspice integrates Xspice, a mixed-mode simulator built upon spice3c1 (and then some tweak is necessary merge it with spice3f5). Xspice provides a codemodel interface and an event-driven simulation algorithm. Users can develop their own models for devices using the codemodel interface.
It could be used for VLSI simulations as well.