Describe The Basic Theory of Electricity

To understand electricity, we must understand what causes the electricity to flow. Electricity is a form of energy. All matter is made up of atoms and atoms have sub-atomic particles. There are three sub-atomic particles, which are protons, neutrons and electrons. The structure is so that the middle, which is known as the nucleus, contains the protons and the neutrons, the electrons are orbiting around the nucleus. The protons in an atom are positively charged and the electrons have a negative charge. The neutrons in atoms have no charge.

The structure is such that the charge of the electrons and protons are attracted to each other and this keeps the electron orbiting the nucleus. The number of neutrons and protons in an atom is the same; also, the number of protons and electrons are the same. For example, the element hydrogen, the atomic number is 1; this means that there is one neutron and one proton and therefore one electron. Atoms need to have the same number of protons and electrons to be stable.

When a charge is given to an atom this causes the atoms to flow and pass onto another atom causing a flow of electrons. The charge will be known as an electro-motive force which is required to move the electrons.

Conductivity is a key part of making systems that allow electricity to flow through them and operate. A conductor is a material which allows electricity to flow through it. This will mean that a material which is a conductor will allow electrons to flow freely and therefore electricity will flow well. In the periodic table of elements we have a group of metals called transition metals, these are the materials which are the best at allow electricity to flow through them. In figure 1 you can see the transition metals in the periodic table, highlighted in yellow.

A semi-conductor is material which allows some electricity to flow through it; these are useful because we are able to control the amount of electricity flowing through a part of a circuit. They are not as conductive as regular conductors; however, they have their applications in electronics. An insulator is a material which has high resistivity; this means that it allows little or no electricity to flow through it. Insulators are commonly used around wire to make sure that they are safe to handle, this will make sure that people do not come in contact with live electricity. Insulators have less or no free electrons which means that are unable to pass of energy through the flow of electrons.

Potential difference is defined as the difference in potential between two points. This means that we look as the volts flowing through one point and we look at the volts flowing through another point, and we use this to find out how strong the flow of electrons is. Potential difference is measured in volts. Current is a measure of how many electrons are flowing and this is measures in amperes. Electrons are so small that we have to scale up how many electrons are flowing through a circuit; we use coulombs to measure the amount of electrons flowing through a point. One coulomb is 6.24*1018

There are two types of current flow, we have conventional current flow and electron flow. Conventional current flow is the electrons flowing from positive side to the negative side. This is what we first thought happened when electricity was discovered, but from test and experiments we know that electrons flow from the negative to the positive side, this is known as electron flow.

Ohms law states that the voltage in a certain point is proportional to the current flowing through that point when the resistance is constant. The equation gathered from this information is V=IR, this is equation allows us to work out the voltage at a certain point when we have the current and the resistance at that point. The equation can also be transposed to figure out current or resistance when we have the other two variables.

V=IR

I=V/R

R=V/I

To conclude we know that electricity is an energy form whereby the electrons in a material flow and this causes is to be transferred through the material. We understand that materials are made up atoms and atoms contain sub-atomic particles. These are neutrons, protons and electrons. Conductors are materials which allow electricity to flow through them; insulators are materials which resist electron flow. Ohms law shows us the relationship between voltage, current and resistance.