Free Circuit Design Tools for Ham Radio

By Dan Romanchik, KB6NU

About a week ago, I started looking for a schematic capture program so that I could easily generate some simple schematics for my upcoming Extra Class study guide. Since I use a Mac as my main computer, I first asked on the Ham-Mac mailing list if anyone knew of a good one. I got several recommendations, including:

– Diptrace,
– Eagle, and
– McCad

Eagle looked like a good choice, although several people mentioned that the user interface “left much to be desired.”

Then, I remembered that I had OmniGraffle, which is a general-purpose diagramming tool. Googling around, I found several sets of electronic symbol libraries that could be used with OmniGraffle. I installed them, and generated a couple of figures for the study guide section that discusses T-network and pi-network filters. It was a reasonably good solution to my problem.

A Web solution
A couple of days ago, though, someone on the local Maker mailing list, pointed me towards CircuitLab, an online schematic capture tool and circuit simulator. I haven’t tried the circuit simulation yet, but the schematic capture tool is really easy to use. It’s much easier to use for drawing circuit diagrams than OmniGraffle.

Another benefit is that it doesn’t matter what computer you’re using. Because it runs in a Web browser, it doesn’t matter whether that browser is running on a Mac or a PC or even a Linux box.

If you set up an account, you can save circuits to your “workbench.” To get you started, there are some sample circuits, such as the 555 timer circuit shown in Figure 1. There’s also some decent documentation and a forum where you can discuss circuits and get some help.

Finally, the price is right, too. It looks like using CircuitLab is completely free. I couldn’t find any pages that required payment.

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When not searching the Web for circuit design tools, you’ll find KB6NU working 30m CW and twittering away about his contacts. His Twitter id is @kb6nu. He would love for you to follow him there. If you don’t tweet, you can still read his blog at www.kb6nu.com.