You read the code by following the path of electrons through the circuit map. See if you can explain it to a friend. Lamps light up. Toasters heat up. Vacuum cleaners vacuum.
Radios turn on.
Things that bring light, heat, movement and sound all need the same thing-electrons. Every time you turn on a lamp, you complete a circuit and electrons can flow. Each lamp is part of an electric circuit until you turn it off again. Most of that circuit is hidden inside the walls. All you can see is a plug in a wall socket and a wire leading to the lamp.