Part 1: Fundamental Concepts

This chapter introduces the concepts needed to understand what a circuit is and provides the background needed to understand the basic principles involved in working with circuits. The first two sections, “Voltage and Current” and “Current and Signal Velocity”, provides a gut feeling for what is happening physically, at the atomic level, in a circuit.  The goal of these sections is to introduce the concepts of voltage and current.  Beyond grasping what voltage and current in a circuit represent, the other information provided will rarely, if ever, be used when dealing with electronics.

The remainder of the sections presented in this chapter do provide information that is important to understand.  If this is your first exposure to electronics, take your time.  It is best if you don’t skip too much of the material presented.

This isn’t the “fun” part of electronics where you learn how to build a radio or an amplifier.  This part of the book is dedicated to developing a basic understanding of how circuits work.  It may seem a bit slow and somewhat tedious.  It is, however, important.  Having a solid foundation to build on makes what follows understandable.   It also equips you with the tools that allow you to understand circuits that you have not seen before.