Welcome to DC Electrics — Basic Principles — Page 1, Lesson 8

Welcome to DC Electrics — Basic Principles. This is the very start of your electrical foundation for the ATPL, so we're going to build it from the ground up, exactly as the syllabus lays out. Let me begin with the structure of this chapter. The topics we will cover include: an introduction, then Electromotive Force (EMF), Current, Resistance, the Factors Affecting Resistance, Units of Resistance, Resistors, Ohm's Law, Power, Series and Parallel Circuits, and Kirchoff's Laws. After that, there are several sets of questions — Theory, Units 1, Units 2, and General — plus an Annex A and answer sections. Now, before we dive into the first page of content, I want you to notice something important about the very first topic listed: Electromotive Force (EMF). That's the driving force behind any electrical circuit. We'll define it precisely when we get there, but for now, know that it's the pressure that pushes electrons around a circuit. Next comes Current — that's the flow of those electrons. Then Resistance — the opposition to that flow. We'll look at what factors change resistance, the units we measure it in, and the components called Resistors that provide a specific amount of resistance. Then comes Ohm's Law, which is the fundamental relationship between voltage, current, and resistance — you'll use this constantly. After that, Power — how much electrical energy is being used per second. Then we get into Series and Parallel Circuits — how components can be connected, and how that changes the total resistance and current flow. Finally, Kirchoff's Laws give us rules for voltages and currents in more complex circuits. So, the very first thing we need to understand is what makes electrons move in the first place. That's Electromotive Force. Let's start there.