Ngspice

Introduction to NGSpice

NGSpice

Ngspice is a general-purpose Electrical / Electronics circuit simulation program for nonlinear and linear analysis. The NGSpice acronym stands for Next Generation Simulation Program With Integrated Circuit Emphasis. Ngspice is a mixed-level / mixed-signal circuit simulator. Its code is based on three open source UC Berkeley spice based software packages: Spice3f5, Cider1b1 and Xspice. Ngspice is part of gEDA project, a full GPL'd (General Public License) suite of Electronic Design Automation tools. It supports the circuits which contain resistors, capacitors, inductors, mutual inductors, independent or dependent voltage and current sources, loss-less and lossy transmission lines, switches, uniform distributed RC lines, and the five most common semiconductor devices: diodes, BJTs, JFETs, MESFETs, and MOSFETs. In addition, it also supports block level simulation of the electrical systems through analog behavior modeling. New devices can also be modeled through advanced xspice-tools. It supports both basic and advanced analysis such as DC, AC, transient, fourier, pole-zero, small-signal distortion, sensitivity and noise analysis. Ngspice is an ongoing project, growing everyday from user’s contributions, suggestions and reports.

Version

Version 23 (Released on June 01st, 2011)

Operating System (OS) required

NGSpice can be used on both Microsoft Windows and Linux Operating Systems.

Please see the associated text box of individual spoken tutorials on the website to decide the versions of software and OS to which it is applicable.

What does NGSpice do?

NGSpice uses mathematical models to replicate the behavior of an actual electronic device or circuit. NGSpice simulates a circuit’s behavior before actually building it which can helps in improving design efficiency by making dummy designs known as such, and providing insight into the behavior of electronics circuit designs. In particular, for integrated circuits, the tooling (photomasks) is expensive, breadboards are impractical, and probing the behavior of internal signals is extremely difficult. Therefore almost all IC design relies heavily on simulation.

Usage of NGSpice

NGSpice is mainly used for the following reasons:

1. The use of a computer program like NGSpice may help us to eliminate circuits that do not work or optimize those circuits that will work before we sit down with a prototyping board or do ugly construction.

2. Used for computer based circuit simulation (Analog, Digital, Mixed mode simulations).

3. Used for different kind of Analysis (e.g. DC, AC, Transient etc.)

4. Simulation of linear and non-linear circuits.

Utility

Ngspice is essentially useful to those who deal with electrical and electronic circuits for various reasons. In academic circle, the students and teachers of electrical and electronics engineering curricula can use to enhance their subject knowledge. The spice circuit simulations are included as a part of curriculum in most of the universities. It is useful for the researchers in electronic devices and circuits. It is also useful for circuit designers practicing engineers in electrical engineering and design automation.

NGSpice Spoken Tutorial - Novice

1. Introduction to NGSpice
   • NGSpice
   • Version
   • Operating System (OS) required
   • What does NGSpice do?
   • Usage of NGSpice
   • Utility
   • Contributors
2. Circuit Elements and Models
   • Elementary Analog devices
   • Sources
   • Digital devices
   • Analog Behavior Modeling (ABM) devices
3. Basic Analysis and Output Commands
   • DC Analysis
   • AC Analysis
   • Transient Analysis
   • Transfer Functions
   • Fourier Analysis
   • Parametric Sweep
   • Control Commands
4. Simulator Variables and Convergence
   • Simulator variables
     • ABSTOL
     • BADMOS
     • PIVREL
     • TEMP
     • LIST
   • Convergence
   • Representative examples for simulator variable and convergence
5. Creating new library templates (for sample parts)
   • From data-sheet specifications of commercial parts
   • Using existing templates
6. Advanced Analysis
   • Pole-zero analysis
   • Small-signal distortion analysis
   • Sensitivity analysis
   • Noise analysis
7. A Few Abbreviations in NGSpice
   • Abbreviations in NGSpice
8. Glossary
   • Glossary
   • Acronyms and Abbreviations

Contributors

Prof. Kannan Moudgalya, Rajendra R Sawant, Rajesh Thakkar, Ananda Murthy R S

Contributors and Content Editors

Minal, Nancyvarkey