Electronics is a physical pursuit in the sense that you have to build circuits to test and use them. However there is a lot to be said for using simulation to try things out. Its much easier and you can check that you have correctly designed a circuit before going to the trouble of building it. The good news is that circuit simulation is a lot easier than you might imagine using open source software.

Electronics is a complicated subject with lots of different types of electronic components. Electronics as it is applied to the IoT or digital electronics in general is in fact a much simpler subject. In particular you can master it with a knowledge of just a small number of devices - the resistor being the number one. In this chapter we look at the basic ways that electricity behaves and how resistors control it.