What is electricity? – Concept of electric charge


Electricity is so present in our daily lives that we often forget its importance until suddenly a blackout occurs. In this article we will look at the concept of electricity, its application in the home and industry. We are also going to delve into the nature of matter in order to understand where electricity comes from as we know it.

Electricity – home and industry

Preserving our food, heating the water in the house, heating and entertainment are some examples of the application of electricity in the home.

In the industry it is used to run machines that require power, such as motors and fans. It is also used to power control systems.

How do all these electrical devices work?

In all cases what happens is that an electric current circulates through these devices, excites their internal circuits and produces an effect.

Types of electric current

There are two types of electric current, direct current (DC in Spanish, DC in English) and alternating current (AC in Spanish, AC in English).

Direct current is generally used to power digital systems such as LED TVs, computers and radios. While alternating current is used to run motors, resistors to generate heat, among others.

It is possible to convert one type of current into another by using the appropriate device. The most common is the transformer we use to charge the smartphone or notebook, these machines are fed by the alternating current from the household sockets and convert it into direct current.

Power Sources

We know thaenergy has to “come out” from somewhere, in general our house is connected to the electrical network of a city or town and we have plugs or sockets.

This energy comes from power plants that use machines that transform a type of energy such as wind, sun or fossil fuels into electrical energy.

generacion de electricidad con turbina eolica. rawson, argentina
Fig. 1: Wind turbines in Rawson, Argentina. Source Wikipedia.

panel solar policristalino para generar electricidad con energia solar
Fig. 2: Polycrystalline solar panel.

In remote places where the power line does not reach, it is necessary to resort to other solutions in order to obtain electrical energy. For example to install solar panels or generators and to apply much the rational use of the energy.

grupo electrogeno para generar electricidad a partir de combustibles
Fig. 3: Generator I received just at the time of writing this article.

What is electricity?

We have talked about its application, the principle of operation of electrical machines and the types of current, now let’s go a little deeper into the nature of matter to understand more deeply

In antiquity it was discovered that matter could be “loaded” in some way, since when rubbing certain materials with others a force of action appeared at a distance like gravity. We are talking about the typical experiment that we do in primary school in which we rub the ruler on our hair and then we can make bits of paper adhere to it.

In addition it was discovered that there were two types of charges, which were later referred to as positive charge and negative charge.

Observing the interaction between these charged materials it was noted that charges of the same type are repelled and charges of dissimilar type are attracted.

These charges present in matter are what give rise to the electric current.


Electricity is widely used in everyday life to power all kinds of devices. The general principle of all these devices is an electric current that circulates through their interior producing an effect.

There are two types of electric current, direct current (DC) and alternating current (AC). We can convert one type of current into another by using the appropriate device.

Electricity is generated by machines that transform different types of energy into electrical energy.

In the matter there are two types of charge, positive charges and negative charges. If two charges of the same type face each other, the result is a repulsive force between the two. If two charges of a different type face each other, a force of attraction appears between them.

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