BASIC ELECTRICAL

What is electricity?

Electricity is defined as "the flow of electrons through simple materials and devices" or "that force which moves electrons."  Scientists think electricity is produced by very tiny particles called electrons and protons.  These particles are too small to be seen, but exist as subatomic particles in the atom. To understand how they exist, you must first understand the structure of the atom.


DESCRIBE the following terms:

a.  Electrostatic force
b. Electrostatic field
c. Potential difference
d. Electromotive force (EMF)
e. Ion charge

The Atom

Elements  are  the  basic  building blocks of all matter.  The atom is the smallest particle to which an element can be reduced while still keeping  the  properties  of  that element.   An atom consists of a positively    charged    nucleus surrounded by negatively charged electrons,  so  that  the  atom  as a whole is electrically neutral.The nucleus is composed of two kinds of subatomic particles, protons and neutrons.The proton  carries  a  single  unit positive charge equal in magnitude to  the  electron  charge.                                            

The neutron is slighty heavier than the proton and is electrically neutral, as the name implies. The Atom particles exist in various combinations, depending upon the element involved.  The electron is the fundamental negative charge (-) of electricity and revolves around the nucleus, or center, of the atom in concentric orbits, or shells.

The  proton  is  the  fundamental  positive charge (+) of electricity and is located in the nucleus.  The number of protons in the  nucleus  of  any  atom  specifies  the atomic number of that atom or of that element.  For example, the carbon atom contains  six  protons  in  its  nucleus; therefore, the atomic number for carbon is six.

In  its  natural  state,  an  atom  of  any element  contains  an  equal  number  of electrons  and  protons. The  negative charge  (-)  of  each  electron  is  equal  in magnitude to the positive charge  (+) of each proton; therefore, the two opposite charges cancel, and the atom is said to be electrically neutral, or in balance.

Electrostatic Force         

One of the mysteries of the atom is that the electron and the nucleus attract each other. This attraction is called electrostatic force, the force that holds the electron in orbit.  This force may be illustrated with lines Without this electrostatic force, the electron, which is traveling at high speed, could not stay in its orbit.  Bodies that attract each other in this way are called charged bodies.  As mentioned previously, the electron has a negative charge, and the nucleus (due to the proton) has a positive charge.

The First Law of Electrostatics

The negative charge of the electron is equal, but opposite to, the positive charge of the proton. These charges are referred to as electrostatic charges.  In nature, unlike charges (like electrons and protons) attract each other, and like charges repel each other.  These facts are known as the First Law of Electrostatics and are sometimes referred to as the law of electrical charges.  This law should be remembered because it is one of the vital concepts in electricity.

Some atoms can lose electrons and others can gain electrons; thus, it is possible to transfer electrons from one object to another.  When this occurs, the equal distribution of negative and positive charges no longer exists.  One object will contain an excess of electrons and become negatively charged, and the other will become deficient in electrons and become positively charged.  These objects, which can contain billions of atoms, will then follow the same law of electrostatics as the electron and proton example shown above. The electrons that can move around within an object are said to be free electrons and will be discussed in more detail in a later section. The greater the number of these free electrons an object contains, the greater its negative electric charge.  Thus, the electric charge can be used as a measure of electrons.