Thinking about drawing and teaching circuits
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.
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 diagram.ly, which is a pretty fancy schematic drawing program that lets you draw all sorts of schematics—circuits, UML diagrams, flow charts and more. Diagram.ly 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.
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.
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.
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.