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NORA Oilheat Technicians Manual

field. Some of the electrons are at the back of the end zone. The electrons have almost no mass, but they carry a negative charge equal to the positive charge of the proton. So a neutral atom has as many electrons in the space surrounding the nucleus as it has protons inside it. The electrons are held close to the nucleus by the electric force of attraction between opposite charges. In different kinds of atoms, the electrons farthest from the nucleus may be bound strongly or weakly. The ones that allow their electrons to escape easily are called conductors. The atoms that hang on tight to their electrons are insulators. The flow of free electrons in a conductor is what we call electric current. If you throw a switch to turn on a lamp five feet away, it takes 40 minutes for the little electrons to fight their way through the conductor from the switch to the lamp. What turns on the lamp right away is a pulse, each electron pushing those ahead of it until the pulse reaches the lamp. The pulse travels almost at the speed of light. If you are feeding the lamp with AC, it is not a pulse that travels but a wave. Each electron vibrates back and forth, passing its energy along to the next, just like molecules of air passing a sound wave or water in the ocean passing a wave. Chapter 8—Basic Electricity 8-29 In case you are interested In this chapter we have talked about what electricity does. We have not really covered what it is. That is because electricity can be confusing. However, some of you might be wondering what electricity actually is. So for those brave souls who want to know more, read on. If you are already hopelessly confused, you can stop reading now. Everything contains electrically charged particles, both positive and negative. These particles make up the atoms that are the building blocks for everything in the universe. Atoms are really, really small. It would take several million of them, lined up, to reach across the dot at the end of this sentence. Each atom is electrically neutral because it contains equal amounts of positive and negative charge. The positive charge of an atom is in the center, called the nucleus. The nucleus is made of protons that have a positive charge and neutrons that have no charge. The number of protons determines what kind of material the atom is. For example, hydrogen has one proton, and oxygen has eight. Circling around the outside of the nucleus are electrons. They are sort of like planets circling around the sun. As in the solar system, there is a lot of empty space. The nucleus is like a marble sitting in the middle of a football Chapter 8 Basic Electricity


NORA Oilheat Technicians Manual
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