Publisher Summary The chapter attempts to explain electricity, its origins, and applications. It begins by explaining about a very small particle that is referred to as an atom. Atoms are made up of three types of particles: protons, neutrons, and electrons. The individual protons and neutrons are much more massive than electron. Only two of these particles have charge. The proton carries a positive charge and the electron carries a negative charge, whereas the neutron carries no charge at all. A very fundamental property of charge is that as charges repel and opposite charges attract. If one brings a free electron next to another free electron, it tends to push the other electron away from it. It is important to realize that it is by the nature of the location of these charges that one measures a voltage. Movement of these charges is known as current. Finally, the chapter gives a brief idea of different instruments such as resistors, inductors, capacitors, batteries, and generators.