# Qucs-S Help documentation : User Manual and Reference Material¶

**Copyright**2015, 2016, 2017, 2018

Permission is granted to copy, distribute and/or modify this document under the terms of the

GNU Free Documentation License, Version 1.1 or any later version published by the Free

Software Foundation. A copy of the license is included in the section entitled “GNU Free

Documentation License”.

Contents:

- Introduction
- Basic Ngspice, Xyce and SPICE OPUS simulation
`Spice4qucs`

subcircuits, macromodels and device libraries`Spice4qucs`

Subcircuits: with and without parameters`Spice4qucs`

subcircuits without parameters`Spice4qucs`

subcircuits with parameters- A second more complex example of
`Spice4qucs`

subcircuits with parameters - Component and circuit libraries
- Using manufacturers component data libraries
- Usage of unmodified SPICE Libraries
`SpiceLibComp`

device- Symbol pattern files format description
- Usage of the whole SPICE library
- Libraries blacklisting

- Device and component modelling with algebraic equations
- The role of algebraic and numeric equations in circuit simulation
- Qucs equations usage with ngspice and Xyce
- Manipulating simulation data with algebraic measurement scripts
- Qucs Equation-Defined Device (EDD) models
- Qucs Frequency Equation-Defined Device (FEDD) models
- Ngspice and Xyce translation/synthesis of EDD and FEDD models

- More advanced circuit simulation techniques.
- Ngspice, Xyce and SPICE OPUS post-simulation data processing with Qucs-S and Octave
- Introduction to capabilities
- Ngspice and SPICE OPUS output data post-processing
- Ngspice, SPICE OPUS and XYCE data post-processing operators and functions
- Xyce simulation output data post processing with the
**Xyce script**component and SPICE .PRINT statements - Ngspice and Xyce H SPICE style
**.measurement**output data processing - Qucs-S emulation of the Qucs
**PlotVs()**function - Qucs-S output data processing with the Octave numerical analysis and visualization package
- Introduction
- Using Octave for numerical analysis and visualization of Qucs-S simulation output data
- The structure and content of Octave
*xxxxxx.m*script files - A second Octave
*xxxxxx.m*script file

- Qucs and SPICE simulation models that work with Ngspice, Xyce and SPICE OPUS
- Introduction
- Spice4qucs component specifications and technical reference
- Capacitor (C)
- Inductor (L)
- Resistor (R)
- Independent AC Current Source (I)
- Independent AC Voltage Source (V)
- Independent DC Current Source (I)
- Independent DC Voltage Source (V)
- Linear Current Controlled Current Source (F)
- Linear Current Controlled Voltage Source (H)
- Linear Voltage Controlled Current Source (G)
- Linear Voltage Controlled Voltage Source (E)
- Probes
- Qucs Netlist
- Ngspice Netlist
- Relay (Voltage controlled switch) (S)
- Diode (D)
- BJT npn (Qucs T, ngspice Q)
- Ngspice diode (D)
- Ngspice linear resistor (R)
- Ngspice linear capacitor (C)
- Ngspice linear inductor (L)
- Ngspice mutual inductor (K)
- Ngspice independent AC voltage source (V)
- Ngspice non-linear dependent voltage and current sources (B)

- Linear and non-linear transformer models
**Two winding transformer model with in phase primary and secondary voltages and winding resistance****Two winding transformer model with out of phase primary and secondary voltages and winding resistance****Two winding transformer model with in phase primary and secondary voltages, winding resistance and fringing inductance****Two winding transformer model with in phase primary and secondary voltages, winding resistance and core saturation****Spice4qucs magnetic core library: symbols and B/H specifications****Two winding transformer model with in phase primary and secondary voltages, winding resistance and core saturation (using XSPICE models)****Three winding transformer model with winding resistance and core saturation effects (using XSPICE models): full-wave rectifier example**

- More complex circuit simulations that demonstrate the use of spice4qucs models

- Ngspice custom simulation technology
- XSPICE standard components and library
- XSPICE user written device models and library
- Introduction to mixed analogue/digital simulation
- Verilog-A compact semiconductor device modelling
- RF simulation with Ngspice, Xyce and SPICE OPUS
- Introduction to capabilities
- Small signal AC S-parameter simulation
- Small signal AC two port network simulation/analysis
- Single tone large signal AC Harmonic Balance simulation
- Multi-tone Large signal AC HB simulation
- The SPICE OPUS large signal AC steady state transient shooting method
- Emulation of Qucs RFEDD components
- RF device models
- More example RF circuit simulations

- Qucs-S/Octave circuit simulation and device parameter extraction interface
- Measurements
- References

A “Technical Description” of the Qucs simulator and implemented device models are available online at http://qucs.sourceforge.net/tech/technical.html.

Qucs-S example schematics can be found in the Qucs-S V0.0.21 source code “examples” directory.

Qucs_S V0.0.21 build can be downloaded from https://ra3xdh.github.io/.