Quite Universal Circuit Simulator (Qucs) is a

free-software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

electronics circuit simulator Electronic circuit simulation uses mathematical models to replicate the behavior of an actual electronic device or circuit. Simulation software allows for modeling of circuit operation and is an invaluable analysis tool. Due to its highly accurat ...

software application released under GPL. It offers the ability to set up a circuit with a graphical user interface and simulate the large-signal, small-signal and noise behaviour of the circuit. Pure digital simulations are also supported using

VHDL The VHSIC Hardware Description Language (VHDL) is a hardware description language (HDL) that can model the behavior and structure of digital systems at multiple levels of abstraction, ranging from the system level down to that of logic gate ...

and/or

Verilog Verilog, standardized as IEEE 1364, is a hardware description language (HDL) used to model electronic systems. It is most commonly used in the design and verification of digital circuits at the register-transfer level of abstraction. It is als ...

. Qucs supports a growing list of analog and digital components as well as

SPICE A spice is a seed, fruit, root, bark, or other plant substance primarily used for flavoring or coloring food. Spices are distinguished from herbs, which are the leaves, flowers, or stems of plants used for flavoring or as a garnish. Spices a ...

sub-circuits. It is intended to be much simpler to use and handle than other circuit simulators like

gEDA The term gEDA refers to two things: # A set of software applications (CAD tools) used for electronic design released under the GPL. As such, gEDA is an ECAD (electronic CAD) or EDA (electronic design automation) application suite. gEDA i ...

PSPICE OrCAD Systems Corporation was a software company that made OrCAD, a proprietary software tool suite used primarily for electronic design automation (EDA). The software is used mainly by electronic design engineers and electronic technicians to ...

Analysis types

Analysis types include S-parameter (including

noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference aris ...

), AC (including noise), DC, Transient Analysis, Harmonic Balance (not yet finished), Digital simulation (VHDL and Verilog-HDL) and Parameter sweeps.

Features at a glance

Qucs has a graphical interface for schematic capture. Simulation data can be represented in various types of diagrams, including Smith-Chart, Cartesian, Tabular, Polar, Smith-Polar combination, 3D-Cartesian, Locus Curve, Timing Diagram and Truth Table. The documentation offers many useful tutorials (WorkBook), reports (ReportBook) and a technical description of the simulator. Other features include the transmission line calculator,

Filter Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

synthesis, Smith-Chart tool for power and noise matching, Attenuator design synthesis, Device model and subcircuit library manager, Optimizer for analog designs, the

Verilog-A Verilog-A is an industry standard modeling language for analog circuits. It is the continuous-time subset of Verilog-AMS. A few commercial applications may export MEMS designs in Verilog-A format. History Verilog-A was created out of a need to st ...

interface, Support for multiple languages (

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

and internal help system), Subcircuit (including parameters) hierarchy, Powerful data post-processing possible using equations and symbolically defined nonlinear and linear devices.

Tool suite

Qucs consists of several standalone programs interacting with each other through a GUI. The GUI is used to create schematics, setup simulations, display simulation results, writing VHDL code, etc. The analog simulator, gnucsator, is a command line program which is run by the GUI in order to simulate the schematic which you previously setup. It reads a netlist file augmented with commands, performs simulations, and finally produces a dataset file. It can also report errors. The GUI includes a text editor which can display netlists and simulation logging information. It is handy to edit files related to certain components (e.g. SPICE netlists, or Touchstone files). A filter synthesis application can help design various types of filters. The transmission line calculator can be used to design and analyze different types of transmission lines (e.g. microstrips, coaxial cables). A component library manager gives access to models for real life devices (e.g. transistors, diodes, bridges, opamps). These are usually implemented as macros. The library can be extended by the user. The attenuator synthesis application can be used to design various types of passive attenuators. The command line conversion program tool is used by the GUI to import and export datasets, netlists and schematics from and to other CAD/EDA software. The supported file formats as well as usage information can be found on the manpage of qucsconv. Additionally, the GUI can steer other EDA tools. Analog and mixed simulations can be performed by simulators that read the qucsator netlist format. For purely digital simulations (via VHDL) the program FreeHDL or Icarus-Verilog can be used. For circuit optimization (minimization of a cost function), ASCO may be invoked.

Components

The following categories of components are provided: * Lumped components (R, L, C, amplifier, phase shifter, etc.) * Sources * Probes * Transmission lines * Nonlinear components (diodes, transistors, etc.) * Digital components * File containers (S-parameter datasets, SPICE netlists) * Paintings There is also a Component library that includes various standard components available in the market (bridges, diodes, varistors, LEDs, JFETs, MOSFETS, and so on).

Transistor models

Qucs supports transistor models, some need to be added by hand. Some have been tested, these include * FBH-HBT * HICUM L0 v1.12 * HICUM L0 v1.2 * HICUM L2 v2.1 * HICUM L2 v2.22 * HICUM L2 v2.23 * MESFET (Curtice, Statz, TOM-1 and TOM-2) * SGP (SPICE Gummel-Poon) * MOSFET * JFET * EPFL-EKV MOSFET v2.6.

References

External links

*
FreeHDL home page

Icarus Verilog home page

Win32 Binaries for Qucs and freehdl

{{CAD software Free electronic design automation software Free software programmed in C++ Electronic design automation software for Linux Electronic circuit simulators Engineering software that uses Qt