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Thinking about drawing and teaching circuits

May 24, 2012

For the longest time, the holy grail of teaching electricity was finding a quick and easy way to draw simple circuit diagrams. I’ve tried some fairly expensive diagramming packages like Omnigraffle, and until recently the easiest tool I could find was the very well named Klunky Schematic Editor, which is a very old school set of HTML pages (it reference Netscape) that let you draw circuit diagrams by clicking and arranging various symbols inside little boxes.

Screen shot 2012 05 23 at 8 29 45 PM

Klunky Schematic Editor

While Klunky gets the job done, I’ve always hoped for something just a bit more modern and flexible. Recently, I’ve come across a few new options.

First is, which is a pretty fancy schematic drawing program that lets you draw all sorts of schematics—circuits, UML diagrams, flow charts and more. is nice—it has more options than you could possibly imagine, but unfortunately, it requires just too many clicks and menu tweeks to make basic circuit diagrams quickly and easily.

Screen shot 2012 05 23 at 11 19 32 PM schematic editor

Next, a fellow physics teacher (I can’t remember who) pointed me in the direction of Digikey’s scheme-it, a web-based diagramming app. Scheme-it is fast, easy to use, and once you finish drawing up your circuit diagrams, you can order all of the parts from Digikey. This is as close to the holy grail of circuit drawing as I’ve come.

Screen shot 2012 05 23 at 11 34 15 PM

Scheme-it schematic editor.

One last tool that I discovered thanks to Taha Mzoughi is the Falstad Circuit Simulator Java applet. This applet lets you choose from hundreds of pre-designed circuits or draw your own by right-clicking the background to bring up a menu of components. You can then simulate the behavior of the circuit and measure voltage and current at various points in the circuit. It’s very cool, and you can change the background to white for screen captures to put into an assessment.

Screen shot 2012 05 23 at 11 40 08 PM

Falstad circuit simluator.

So why do we do so little with electronics?

As I was exploring these various apps, I got to thinking how most of the physics classes I’ve taught barely use 1% of the functionality of these schematic drawing programs. We only use a few components (batteries, resistors, capacitors and maybe inductors) of the 100’s of possible components. Two of the recent Global Physics Department meetings have featured some very cool applications of electronics that tell me I could be doing so much more. Last week, Steve Dickie talked about how he teaches an electronic class that ultimately has students designing some very cool projects. This week, Kevin Karplus talked about how he created a simple compartor circuit to trigger an arduino to help measure the speed of sound in a metal rod.

Both of these talks got me wondering why we don’t do more with electronics in high school. Obviously, time is a huge factor here, but I wonder why we bother having students play with parallel/series circuits, etc, and in many physics courses, never push them to build anything useful. For many students, these tiny morsels of electronics lessons become a sort of dead-end knowledge of why Christmas lights are wired in series and your house is wired in parallel. It seems to me like electronics might be one of those places in the curriculum where a bit more investment of time could pay huge dividends.

7 Comments leave one →
  1. Cristy permalink
    May 24, 2012 9:20 am

    I’m assuming most have heard of the phet simulations, but in case you haven’t, their circuit construction kit is quite impressive and I use it during my electricity unit.

    • May 24, 2012 9:48 am

      Yes, CCK is awesome. It isn’t super well suited to drawing schematics, just because it has a limited set of components, and the wires can’t be drawn orthogonally. But as a teaching tool, it’s the best, and students really love it.

  2. May 27, 2012 2:44 am

    It is surprising that we don’t spend more time on electronics – especially given how reliant our students are on electronic devices. This has led me to switch my electricity unit completely around. Usually I start with electrostatics and end with talking about batteries and other sources of voltage. This time the first day we spent messing around and exploring solar cells, spinning motors by hand, connecting lemons together with dissimilar metals, and measuring voltage output.

    Granted, they aren’t familiar with what ‘voltage’ really means, and don’t really know what they are actually measuring when they do this. I think this adds a bit of perplexity to the situation, and has really driven some interesting discussion thus far during class.

    I think that is the reason we don’t typically get students building electronics – we usually insist on the theory first, and building up to the concept of circuits using this theory. I read Creating Innovators (did you ever get your copy?) and realized that electric circuits is one of those topics with many layers that can be peeled back as needed while exploring a bigger context problem. The students know about charge and voltage and current because they have heard the words and seen it on/around their own electronic devices. They rarely get to actually experiment with them.

  3. May 28, 2012 7:01 am

    Diagramly is more of marketing tool for our underlying diagramming library, mxGraph. We try and polish the UI as far as we can, but we have to be careful not to implement domain specific functionality in the back-end, our customers wouldn’t be too impressed. And yes, scheme-it’s visualization is mxGraph too.

  4. June 26, 2012 9:38 am

    Hi John, sorry I missed this the first time around. If you don’t need to simulate, then you might have an excellent circuit drafting tool on your computer already: Visio. Just open the Electrical Engineering palettes and you’ll have a huge number of circuit components available. The UI is quite good, allowing you to right-click on any component in order to switch among many varieties of a given component. Also, you can drag and drop to embed a Visio snippet into a Word document (or other Office document), then edit easily from within Word. I don’t usually plug for Microsoft products, but Visio is my first choice for small schematics that will end up in quizzes.

    • June 26, 2012 9:20 pm

      Thanks for this tip. I’ve heard good things about Visio, but I work on a Mac, and so it’s not an option for me.

  5. June 28, 2012 1:20 am

    I’ve started using which works fairly well if the limited set of components they include are adequate. It is a browser-based editor and simulator that works fairly well (though the graphs that the simulator produces are incredibly ugly).

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