REVIEW OF FUNDAMENTALS
OF ELECTRICITY WITH
For a better understanding of this text, a certain basic knowledge of electricity is essen-
tial. The objective of the appendix is to cover only the necessary principles of electricity.
Each principle is illustrated with one or several applications. Only minimal ac (alternating
current) theory is presented. Where possible, these applications favor electrical communi-
cations. Analogies to assist in the understanding of a concept are used where appropriate.
We cannot see electricity. We can feel its effects such as electrical shock, the generation
of heat, and the buildup and decay of magnetic and electrical fields. For example, a
compass will indicate the presence of a magnetic field.
It is assumed that the reader has had at least three years of high school mathematics
including algebra, trigonometry, and logarithms. For those who feel that their background
in mathematics is insufficient, Appendix B gives an overview of those basic essentials.
WHAT IS ELECTRICITY?
We define electricity as the movement of electrons through a conductor.
stances are good conductors and other substances are poor conductors. Poor conductors
are called insulators. The various materials or substances we have here on earth run the
gamut, from superb conductors such as platinum, gold, silver, and copper to extremely
good insulators such as glass, mica, polystyrene, and rubber.
The movement of electrons through a conductor is measured in amperes.
In fact 1
ampere is the flow of 6
.24 × 10
electrons per second past a given point in a conductor.
Encyclopedia Brittanica defines electricity as "The phenomenon associated with positively and negatively
charged particles of matter at rest and in motion, individually or in great numbers."
An ampere is a unit of electrical measurement. All units of electrical measurement are named for scientists
credited with discovering the particular phenomenon, and often providing a mathematical analysis of that
electrical phenomenon. Ampere is one example.
Fundamentals of Telecommunications, Second Edition, by Roger L. Freeman
2005 by Roger L. Freeman