Open source or free tools for electronic design
A list of tools that are actually helping me much
Today I am going to share a list of free tools I use very frequently when designing electronic systems. This list does contain only high quality tools I have direct experience of. I am relatively new to some of them (I started using KiCAD one year ago), but other, like Octave, have been companions for few decades. During this time, I have been able to see a very significant evolution in capabilities and stability.
Schematic capture and PCB design - KiCAD
Today, when I have to do personal electronics related projects that include schematic capture and PCB design, I use KiCAD (https://www.kicad.org/). It is a tool that is gaining a lot of momentum an is continually improving. Today contains many professional-like features.
It offers symbol and footprint editor for libraries (with a large number of already available components), an schematic and PCB editor, Gerber viewer and a set of electronics related calculators including resistors series, attenuation calculators, AWG cables tables and their ampacity, etc.
It is available for Linux, Windows and MacOS.
There are some PCB manufacturers like Eurocircuits that accept PCB definitions in KiCAD native format. You may not need to generate Gerber files.
If budget is real limitation, KiCAD is an option to explore. It is certainly for home projects.
Octave
GNU Octave (https://octave.org/) is a scientific programming tool that is largely compatible to Matlab syntax, but as being part of the GNU project, is available for most Operative Systems. It has very powerful calculation and graphic capabilities based of matrices.
I always have an open text console of Octave in my desktop. I use it as an alternative to a scientific calculator, much more powerful and user friendly.
However, most people uses the GUI interface. Both can coexist in the desktop. I use it to write scripts of complex programs.
As Matlab does, also contains a large number of toolboxes. For example, I have used one for remote control of electronic instrumentation.
Electronics calculator - Saturn PCB
For many daily use calculations (trace current capacity, via resistance, ...), I use SaturnPCB, a nice all-in-one calculator that can be reached at https://saturnpcb.com/saturn-pcb-toolkit/. In the image that follows, you can see the full list of functions it supports.
Saturn is an executable and is available just for Windows.
For transmission line calculations (and many others) uses IPC recommendations. I does not contain a Maxwell equation solver and because of that, provides instantaneous calculations.
Reference and formulas
Another reference source I use much, this time in the form of paper booklet, is Texas Instruments Analog Circuits Companion. It is available free of charge from TI in the form of PDF file at http://www.ti.com/analogrefguide. There is a 2019 revision but I am very happy with my 2015, 98-pages booklet. This format (paper) is available for any existing operative system on Earth :-)
It includes various chapters including: Conversions, Discrete, Analog, Amplifier, PCB and Wire (the one I use more), Sensor and A/D conversion.
Transmission line solver - Sierra Circuits
In the last few months I have discovered a Maxwell equation’s solver for transmission lines that is available online by Protoexpress, which is a PCB manufacturer. The Impedance Calculator is one of the Designer’s Tools they provide and it is a very high quality one.
I have been able to compare results of real circuit against other commercial solvers and the difference in Z0 results is in the order of 1 % which is a very reasonable value.
As it is an online tool, it is operative system agnostic: all you need is a web browser.
Analog simulation - LTspice
For analog simulation I have been using different tools but the one I use now is LTspice that can be reached at Analog Devices. The followers of this post have already seen various simulations with LTspice (and I hope they will continue doing).
It is a powerful, fast, and free SPICE simulator software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Using it is sometimes a bit awkward, has relatively low number of options but includes almost everything you may need. Worth mentioning that it is very well documented.
It is available for various Windows versions (including Windows XP) and MacOS.
Gerber viewer - gerbv
Gerbv is an open source Gerber file (RS-274X only) viewer. Lets you load several files on top of each other, do measurements on the displayed image, etc. Besides viewing Gerber files, you may also view Excellon drill files as well as pick and place files.
You can reach it at https://gerbv.github.io/.
As it is a free/open source program, it is available for many operative systems including Windows, Ubuntu Linux and other Linux platforms.
I have been using gerbv long time to visualize professional PCBs an performs really well.
The list of free tools to support electronic design is very large. In this post, I have shown some that I am frequently using in a profesional context.