Schematic Capture for publishing

Programs for drawing circuits

Inkscape

File:Transistor amplifier blocked emitor.svg

Example of Inkscape's SVG output

Inkscape [1] has a pretty good interface and nice output, but it is specifically meant for artistic drawing and not diagramming. There is a plan to introduce some more diagramming features in the future, but the developers don't want to go too far in that direction for fear of bloating past their primary art focus. They've just added the ability to create program extensions, though, which could be useful for writing some kind of circuit drawing extension. As of January 2006, Inkscape supports drawing connections (wires) between anchors on objects, which makes it much nicer for circuits, but still not a complete solution.

There is a (small but extensible) library of symbols available.

File:Electrical symbols library.svg

Library of electrical symbols for diagramming

Creating diagrams using this template is slightly slower than in specialised programs, but it is very flexible and produces nice vector output.

Dia

File:Star-Triangle transformation.png

Star-triangle transformation drawn with Dia

Somewhat of a compromise between the previous two, Dia [2] exports in SVG, has a small library of electronic components, and a grid (snap feature located in the bottom left corner of the diagram window). While Dia cannot rotate objects, it can flip them horizontally or vertically. This option is found in the properties for each object (right click->properties). To access the circuit object library, you change the category selector in the main window.

SIMetrix

File:Simetrix sample.PNG

Common emitter amplifier drawn using SIMetrix.

SIMetrix [3], as of version 5.40b (Jan 2008):

Advantages:

• Nice looking output.
• Schematic editor with SPICE simulator.
• Free version with unlimited schematic drawing and editing.
  • Hierarchical schematics
• Selection of colours for components, wires, etc. for easy identification.
• Zooming facility, auto-routing and snap-to-grid.
• Simple placement of components — select and click-to-place with mouse.
• Automatic repeat placement of last component.
• Can save a schematic as an SVG or other graphic file.
• Can save schematics in an ASCII or binary format — documentation for the ASCII format is provided with the installation.
• Free version for Windows or Linux may be used indefinitely; program may be freely shared (per SIMetrix 5.40b splash screen)

Disadvantages:

• Free version has limited simulation capability (not applicable for drawing schematics).
• Not open source
• Email registration required to receive download link (no password or user account needed)

PSTricks

File:Sallen key filter generic.png

Sallen–Key filter drawn with pst-circ

pst-circ [4] is a circuit drawing package implemented with PSTricks [5], which allows TeX users to "code" figures with the aid of PostScript. Packages like pst-eps or preview allow for easy production of images with tight bounding boxes.

Advantages:

• Nice looking output.
• Free version with unlimited schematic drawing and editing.
• Transparent source that is diffable.
• Full use of PostScript (e.g., colors, bitmaps, vectors, etc.).
• Full use of TeX (e.g., mathematical formulas and nicely typeset text).
• Many symbols available (e.g., zigzag and chemical dipole symbols, transistors, FETs, analog, digital).
  • Symbols that are not available can easily be drawn with drawing primitives (lines, boxes, etc.).
• 3D images and effects available.

Disadvantages:

• Have to know how to use TeX (or LaTeX).
• No analysis features (i.e., it is just a drawing tool).

KiCad

File:Kicad SVG Output Sample.svg

Unbalanced Splitter drawn with KiCAD

Having recently moved to SourceForge, KiCAD KiCAD is an open source suite of tools including schematic design. It has some nice features:

• Snap to grid
• Component libraries with built-in editor
• Rotate components
• Moving a component moves attached traces when pressing CTRL while clicking the group to move.
• Outputs in SVG (which works with OOo's SVG import tool)
• Open source and actively maintained

But isn't perfect:

• Doesn't route around components
• SVG output includes page border, title, etc (can be cropped with something like InkScape)
• Part labels and values in SVG output are rendered as lines (thus the letter "M") is 4 line segments... making them very difficult to change later.
• Can't use Greek in labels, which means no Ω on resistor values.

Qucs

File:Qucs Sample Circuit Screenshot.png

Practice problem for node equations

Qucs [6] (Quite Universal Circuit Simulator) is an open source (GPL) circuit simulator. It is very easy to work with for drawing schematics. It is close to being an ideal tool for drawing schematics for use in documentation, but lacks SVG support.

Feature Comparison

The Electronics Project has a list of desirable features for a circuit drawing program. This table attempts to summarize which of the features each of the above programs has.

The "Easy circuits" column is specifically answering the question: "Is it easy to use this program to draw circuit layouts?" This is to help clarify that while programs like Inkscape and Dia may pass all the criteria, they are not good choices for drawing circuits. They are easy to use for other tasks, but this chart is specifically geared toward finding a good circuit drawing program.

The "Attach wires" column answers the question: "Once I have a schematic, if I move some component, do the wires that were attached to it move so that they stay attached?"

Note that WikiTeX + gschem is left out of the chart as it is a server-side solution, not a client-side application. To make it a practical solution, one would need a GUI to create the schematics that could export them into the proper format for processing by the server.

Program	Free	Cross Platform	SVG	Library	Grid	Attach wires	Drawing	Bezier curves	Easy circuits
Inkscape	yes	yes	yes	partial	yes	yes	yes	yes	no
Xcircuit	yes	yes	with help	yes	yes				yes
Dia	yes	yes	yes	yes	yes	yes	yes	yes	no
Gimp	yes	yes	no	no		no	yes		no
Klunky	yes	yes	no	yes	yes	no	no	no	yes
Microsoft drawings	no	no	no	no		no	yes		no
SIMetrix	no	yes	yes	yes	yes	yes	yes		yes
pst-circ	yes	yes	yes (with help)	yes	yes	yes	yes	yes	yes
KiCAD	yes	yes	yes	yes	yes	yes(*1)	yes	no	yes
Qucs	yes	yes	no	yes	yes	yes	yes	no	yes
gnu Electric	yes	yes		partial	yes	yes	partial		yes
gEDA gschem	yes	with Cygwin	with help (PNG)	yes	yes	yes	yes		yes

(*1) Use the "g" key (instead of "m") to "Grab" a component and drag it with all connections.

Rejected

• XCircuit. Not for Windows, GUI ugly as hell.