Did you ever stop to think about what is happening when you flip on a light switch? We take for granted that it will turn on every time. We don’t stop to think about the evolution that went into making that light switch possible! But what does this have to do with audio? The answer is, a lot! The ability to record anything has been largely dependent on electricity for a very long time. In this chapter, we will take a very basic look at some of the fundamentals of electricity and how these concepts apply to the audio world.