Articles

Understanding Electrical Principles.

Electrical diagnostics is one of the most challenging areas that today’s automotive technician will encounter. Understanding electrical principles is a vital beginning for more involved diagnostics. Vehicles have become increasingly complex than ever before. Hydraulic and vacuum controls and components are no longer commonplace. The average technician needs to be knowledgeable and familiar with electricity and the principles of which it operates.

Most electrical tests are described in the various shop manuals that are readily available, both on line and the almost outdated shop manual. Accurate diagnostics often require specialized test equipment and an assumption that the technician has a general familiarity with how to operate said equipment. A basic understanding of electricity and the nature of it’s properties is essential. This is what this article is designed to explain.

All matter in our universe is made of atoms. Each atom consists of smaller parts called protons, electrons and neutrons. A physical model of a typical atom is often compared to a solar system. The center of the atom, called the nucleus, is made of neutrons and protons. Neutrons have a neutral electrical charge, but all protons have a positive electrical charge. The electrons in an atom spin rapidly around the nucleus (neutrons and protons) like the planets orbit the sun. Electrons are charged negative and weigh 1/1800 as much as a neutron or a proton.

If the number of electrons in an atom is equal to the number of protons, the atom has a neutral charge because the electrons are negative and the protons are positive. So if an atom has more electrons than protons it would have a negative charge, and if an atom has more protons than electrons it would have a positive charge. Electrons circling around the nucleus are orbiting at different distances.

Atoms in a solid are mostly space much like our solar system. Picture in your mind, a spinning fan with only 2 blades. If the fan spins fast enough, the human eye perceives it to be a solid surface. If a rubber ball was tossed into a spinning fan it would bounce back as if it hit a solid surface even though the fan is mostly space. The atom is much the same idea, the electrons spin around the nucleus at speeds as high as 4000 miles per second. Thus the atom appears to be a solid.

Imagine several satellites orbiting the earth at various distances. Some satellites are so close to the earth’s surface that they are able to orbit the earth in one hour. Other satellites are so far away from the earth, they take 24 hours to complete an orbit. The satellites that are close to the earth are bound by a gravitational pull, and the satellites that are farthest away from the earth have less gravity forces acting on them. Likewise, the electrons in an atom that are farthest away from the nucleus are loosely bound while the electrons that orbit close to the nucleus are tightly bound.

In many material objects the outer electrons can be removed from and added to other atoms because of their far distance from the nucleus.

Atoms that loose an electron will have more protons (+) than electrons (-) causing the atom to have a positive charge. An atom that gains that electron will have more electrons (-) than protons (+) and thus would have a negative charge. Atoms with either extra or missing electrons are called ions. This is the basics of electrical principles and positive and negatively charged atoms.