Get to grips with electricity and electrical theory with this brief introduction of the basic princples.

At its simplest, electricity can exist described as a form of energy brought almost by charged particles either statically, or through charge or current.

Essential to understanding where electricity comes from and what information technology is, you first need to proceeds a unproblematic understanding of atomic theory.

All matter is formed of atoms, which can be arranged together equally molecules. An atom isn't a solid – it is fabricated upwardly of three main parts: protons, neutrons and electrons.

At the centre of an atom is the nucleus , this is where you will detect the protons and neutrons . Protons are positively charged and neutrons (as the proper name suggests) take no electric charge. Electrons are negatively charged and they circumvolve effectually the nucleus .

The negatively charged electron is held in identify by the positive charge of the proton. This is considering dissimilar poles (or opposites) attract and like poles repel.

An atom is neutral if the number of electrons in it is equal to the number of protons. Each chemical element has a set number of protons and electrons.

Electrons make full up valence shells around the nucleus. The shells are energy levels and can hold a given number of electrons – the kickoff vanquish holds 2, the second 8, the third 18 etc. If the outer beat of an atom if filled with the correct amount of electrons then the cantlet is inert or unreactive. The electrons in the outer shell are known as valence electrons.

What is covalent bonding?

Not-metal atoms can combine together past sharing electrons. These shared electrons hold the 2 atoms together to class molecules – for example in water where hydrogen and oxygen atoms share electrons. This is known as covalent bonding. Covalent compounds don't have whatsoever costless electrons and no ions and therefore don't conduct electricity.

What do valence electrons practice?

Because they are in the outermost beat out, valence electrons are far away from the nucleus of an atom, and the link betwixt the two is weak. Taking copper as an example (see diagram), the electron can gain free energy, break free and move about within the structure of the material, where information technology can combine with another atom. An cantlet that loses an electron becomes positively charged (this is a positive ion ). This volition attract a free electron. Within a piece of copper there are millions of atoms with many free electrons moving near. At any fourth dimension the number of protons is equal to the number of electrons (fixed and free) and the material has no charge.

What is current flow?

Normally, the direction and motility of costless electrons in an cantlet is random. Nevertheless, in our instance of the copper, if a piece of copper is connected to an external electrical supply the moment of electrons becomes ordered. This orderly movement of electrons is current flow.

Electrons move in the contrary management to conventional current flow, so electric current flows from positive to negative, while the electrons inside the atoms flow from negative to positive.


What is a Coulomb?

A coulomb is the unit of electric charge . The symbol for electric charge is Q . One coulomb is 6.24 x 10 18 electrons, or 6.2 meg million million electrons.

A electric current of one ampere will catamenia if 6,240000,000000,000000 electrons tin be moved by a betoken in a excursion in one second. The sheer numbers involved in this makes it difficult to cope with, and so the coulomb is used instead.

One ampere = One coulomb/ One second

What is an ampere?

The ampere is the unit of measurement of electric electric current . The symbol for electrical electric current is I .

When computing electrical current or charge, the unit of time used is the second. The symbol for this in formula is t .

So: I = Q/t Amperes

For case, if one coulomb of electricity flows in a circuit for 2 seconds:

I = Q/2 so 1/2   =   0.5A

What is electro-motive force?
Electrons are moved around a excursion by the force of an external power supply. This force is known as the electro-motive force .

The symbol for electro-motive force is EMF .

EMF is measured in Volts .

What is resistance?

The positive charge of the protons in the nucleus of an atom pulls the electrons. The EMF has to overcome this opposition, which is known as resistance .

The symbol for resistance is R .

It is measured in Ohms (Ω)