Electrons Theory of Electricity

What is Electricity?

What is Electrical Quantities?  (Voltage, Current, Resistance)

Electrons Theory of Electricity:

All matter in this universe is made up of atoms and an atom consists of a central nucleus containing minute particles called protons and neutrons. Surrounding the nucleus there are a number of electrons in various orbits. 

It is due to the movement of electrons, the behavior of electrons is more important. But there is one thing common for both protons and electrons and that is their electric charge. This charge is considered as the quantity of electricity. Electron and proton both possess exact same amount of charge, but they are opposite in nature. The electron has a negative charge, whereas the proton has a positive charge. All atoms in their normal state have the same number of protons and electrons and hence they are electrically neutral. The protons are strongly bonded to the nucleus and they cannot be separated from nucleus normally. Electrons are also associated with their orbits, but there may be some electrons in the outer orbits which are loosely associated with the atom. These electrons can be separated from atom if adequate condition is imposed. If one or more of these types of loosely associated orbiting electrons leave the parent atom, the charge balance in atom is disturbed.

There are some materials whose valances electrons are so loosely associated with the parent atoms that numbers of these electrons can be disassociated from their orbit even at room temperature. These disassociated electrons are called “free electrons”.

All the materials in this universe fall under three major groups. According to the presence of free electrons the materials are classified as conductors, semiconductors and insulators. In general, we can say that the conductors have many free electrons within the material. Insulators have very few free electrons (ideally none), and semiconductors fall somewhere between these two extremes.

Whenever a conductor comes under influence of an electric field, which means when potential difference is applied across the conductor, the free electrons experience a force towards the high potential side. This force makes the free electrons to drift through the conductor towards the higher potential end of the conductor. This flow of free electrons is the cause of electricity.

·        The force which flow of free electrons is called VOLTAGE. Measuring unit of voltage is VOLT and used meter for testing is voltmeter.

·        The rate (Quantity) of free electrons in the flow is called CURRENT. Measuring unit of Current is AMPERE and used meter for testing is Ammeter.

• The opposition offered in the flow of free electrons is called Resistance. Measuring unit of Resistance is OHM and used meter for testing is Ohmmeter.

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