4. Schematics

In the previous lesson, I showed a drawing of the circuit as it would appear physically in front of us. It looked like this:

blink_bb_2

While this is a useful representation, it can quickly get cluttered when there are many components. It is also quite difficult to draw by hand. Instead, most electrical circuits are drawn as schematics. They are more abstract than the pictorial representation above and are easier to create.

blink_schem

The resistor is now represented by a zig-zag line (I call them “Charlie Brown shirts”) with a label giving its resistance. The LED is also represented by its own symbol, and the Arduino is also represented abstractly, with the pin locations no longer matching where they physically appear on the board.

Learning how to read schematics

I could write a long lesson about reading schematics, but I don’t think it would be any better than this very nice tutorial from SparkFun. Please read it carefully.

Drawing schematics

There are many computer programs available for drawing schematics. You will need to do so in some of your exercises and definitely in your projects. I think it is also useful to show pictorial representations as well. To draw both of these, Fritzing is a valuable and widely used tool. It is possible to get it for free, but if you have the means, I could encourage you to make the suggested donation (€8). Fritzing is fairly self-explanatory and easy to use.