RING-WEAR 4161290 - Caterpillar

Introduction to Electricity
Flashlights, electric drills, and motors are electric. Computers and televisions are refered as electronic.Any component that works with electricity is electric, including both flashlights and electric drills, but not all electric components are electronic. The term electronic refers to semiconductor devices known as electron devices. These devices depend on the flow of electrons for operation.
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To better understand electricity, it is necessary to have a basic knowledge of the fundamental atomic structure of matter. Matter has mass and occupies space. Matter can take several forms or states. The three common forms are a solid, a liquid and a gas. This course will provide a basic understanding of the theoretical principles needed to develop a foundation for studying and working with electrical circuits and components as a Caterpillar technician.Matter and Elements
Matter takes up space and has weight when matter is subjected to gravity. Matter consists of extremely tiny particles grouped together to form atoms. There are approximately 100 different naturally, occurring atoms called elements. An element is a substance that cannot be decomposed any further by chemical action. Most elements have been found in nature. The following are examples of some of the natural elements: copper, lead, iron, gold and silver. Other elements (approximately 14) have been produced in the laboratory. Elements can only be changed by an atomic reaction or nuclear reaction. Elements can be combined to make compounds. The atom is the smallest particle of an element that still has the same characteristics as the element. Atom is the greek word meaning a particle too small to be subdivided.Atoms
Although an atom has never been seen, the structure fits evidence that has been measured accurately. The size and electric charge of the invisible particles in an atom are indicated, by how much the atoms are deflected by known forces. The present atomic model, with a nucleus at the center was proposed by Niels Bohr in 1913. The atomic model is patterned after the solar system with the sun at the center and the planets revolving around it.
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The center of an atom is called the nucleus. The nucleus is composed primarily of particles called protons and neutrons. Orbiting around every nucleus are small particles called electrons. These electrons are much smaller in mass than either the proton or neutron. Normally, an atom has an equal number of protons in the nucleus and electrons around the nucleus. The number of protons or electrons is called the atomic number. The atomic weight of an element is the total number of particles, protons, and neutrons that are in the nucleus.
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Illustration 3 shows the structure of two of the simpler atoms. Illustration 3(a) is an atom of hydrogen, which contains 1 proton in its nucleus balanced by 1 electron in the orbit or shell. The atomic number for a hydrogen atom is 1. Illustration 3(b) shows a simple atom of helium, which has 2 protons in its nucleus balanced by 2 electrons in orbit. The atomic number for helium