Electrical Fundamentals - Introduction to Matter, Energy and Electricity
A. Bhatia, B.E.
Electricity is a fundamental component of everyday lives. But have you ever wondered, what is electricity and where does it come from!
The answer to this question begins with an understanding of the structure of matter. All matter is made up of atoms, which are made of tiny particles called protons, neutrons and electrons. The proton has a positive charge, the neutron no charge and the electron a negative charge. Electricity comes from the movement of electrons among the atoms of the matter.
This course provides you with insight of the basic concepts and fundamentals behind electricity.
This 4-hr course
material is based entirely on Naval Education and Training Materials (NAVEDTRA
14173), Electricity and Electronic Training Series; Module-1 "Introduction
to matter, energy and direct current" and covers Chapter 1.
This course includes
a multiple-choice quiz at the end, which is designed to enhance the understanding
of course materials.
At the conclusion of this course, the student will be able to:
This course is aimed at students, professional engineers, service technicians, energy auditors, operational & maintenance personnel, facility engineers and general audience.
Electricity is a physical phenomena involving positive and negative charge. When these charges are in motion they may produce heat, light and magnetism. When charges are not in motion, static electricity can manifest itself as a force such as clothes clinging to each other when they are removed from a dryer.
conducted through some things better than others do. Its resistance measures
how well something conducts electricity. Some things hold their electrons very
tightly. Electrons do not move through them very well. These things are called
insulators. Rubber, plastic, cloth, glass and dry air are good insulators and
have very high resistance. Other materials have some loosely held electrons,
which move through them very easily. These are called conductors. Most metals
-- like copper, aluminium or steel -- are good conductors.
In this course, you
are required to study Naval Education and Training Materials (NAVEDTRA 14173),
Electricity and Electronic Training Series; Module-1 "Introduction to Matter,
Energy and Direct Current" Chapter 1:
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All matter is made up of atoms, and atoms are made up of smaller particles. The three main particles making up an atom are the proton, the neutron and the electron. Electrons spin around the centre or nucleus of atoms and is made up of neutrons and protons. Electrons contain a negative charge, protons a positive charge. Neutrons are neutral -- they have neither a positive nor a negative charge.
Each atom has a
specific number of electrons, protons and neutrons. But no matter how many particles
an atom has, the number of electrons usually needs to be the same as the number
of protons. If the numbers are the same, the atom is called balanced, and it
is very stable. Some kinds of atoms have loosely attached electrons. An atom
that loses electrons has more protons than electrons and is positively charged.
An atom that gains electrons has more negative particles and is negatively charge.
A "charged" atom is called an "ion."
When electrons move among the atoms of matter, a current of electricity is created. This is what happens in a piece of wire. The electrons are passed from atom to atom, creating an electrical current from one end to other.
The electrons of different types of atoms have different degrees of freedom to move around. With some types of materials, such as metals, the outermost electrons in the atoms are so loosely bound that they chaotically move in the space between the atoms of that material by nothing more than the influence of room-temperature heat energy. Because these virtually unbound electrons are free to leave their respective atoms and float around in the space between adjacent atoms, they are often called free electrons.
In other types of materials such as glass, the atoms' electrons have very little freedom to move around. While external forces such as physical rubbing can force some of these
electrons to leave their respective atoms and transfer to the atoms of another material, they do not move between atoms within that material very easily.
This relative mobility of electrons within a material is known as electric conductivity. Conductivity is determined by the types of atoms in a material (the number of protons in each atom's nucleus, determining its chemical identity) and how the atoms are linked together with one another. Materials with high electron mobility (many free electrons) are called conductors, while materials with low electron mobility (few or no free electrons) are called insulators.
All matter is made up of tiny particles that have electric charges. Some of these particles have a positive charge and other have a negative charge. Rubbing two objects together may cause some of the negative charges to rub off one object. The charges move to the second object. This gives the second object a greater negative charge than the first object. A flow of electric charge is called "electric current."