Practical Electronics: Components and Techniques

Chapter 1. Electrons in Motion

The field of electrical theory and electronics is huge, and it can be somewhat daunting at first. In reality, you don’t need to know all the little theoretical details to get things up and running. But to give your efforts a better chance at success, it is a good idea to understand the basics of what electricity is and how, in general terms, it works. So that’s what we’re going to look at here.

The main intent of this chapter is twofold. First, I want to dispense with the old “water-flowing-in-a-pipe” analogy that has been used in the past to describe the flow of electrons in a conductor; it’s not very accurate and can lead to some erroneous assumptions. There is, I believe, a better way to visualize what is going on, but it does require a basic understanding of what an atom is and how its component parts work to create electric charge and, ultimately, electric current. It might sound rather like something from the realm of physics (and, to be honest, it is, along with chemistry), but once you understand these concepts, things like fluorescent lights, neon signs, lightning, arc welders, plasma cutting torches, heating elements, and the electronic components you might want to use in a project will become easier to understand. The old water-flowing-in-a-pipe model doesn’t really scale very well, nor does it translate easily to anything other than, well, water flowing through a pipe.

Second, I’d like to build on this atom-based model to introduce some ...