We explain to you what electric current is, what it is and what electric intensity consists of. In addition, the types of electric current and their effects.
what is electricity?
The flow of an electric charge through a conductive material is called electric current , due to the displacement of electrons within its molecular structure, which generates at the same time an electric field around it.
This movement of particles always starts at the positive pole of the material , but occurs in the negative-positive direction, since electrons (negatively charged) are attracted to positivity, leaving a space that occupies another behind you and so on. .
To transmit, the electric current requires materials that have a large share of free electrons , that is, located in its last orbit around the nucleus and therefore susceptible to mobilization, being less strongly attracted to it.
In that sense, one can distinguish between conductive, semiconductor and insulating materials, according to their ability to transmit the electric current (good, low and zero, respectively).
The first experiments with electricity in the eighteenth century had only electric charges obtained by rubbing (static) or induction, so it would be necessary to wait until 1800 to check the constant movement of an electric charge, when the Italian physicist Alessandro Volta will invent the electric battery.
This name is called the flow of electric current , that is, the speed of displacement of charges on the material, comparable to the force of a stream of water in a river, capable of mobilizing charges and carrying out a quantity of work.
According to the International System (SI), this intensity is normally measured in Coulombs per second (C / s) , which is equivalent to an ampere (A); basic unit of electricity and common use, which gets its name from the French physicist André-Marie Ampère. To measure the intensity of the electric current, a galvanometer or ammeter is used.
Types of electric current
The electric current, according to its nature, can be of several types:
- Direct current (DC) . Also called direct current (CD), it consists of a flow of electricity that does not change its direction in time , that is, it is produced based on a difference in electrical potential (voltage) whose terminals of greater and lesser potential are not interchangeable . In other words, its sense of circulation is always the same.
- Alternating current (AC) . Unlike the continuous one, it is a form of electricity whose flow direction varies cyclically, forming sine waves of current. It is this type of electricity that is much easier to transform than the continuous one, which is why homes and businesses receive it . It was invented by Nikola Tesla at the end of the 19th century.
- Three phase current . The three-phase current is the most commonly generated form of electricity, and consists of three alternating currents of identical frequency and amplitude, given in a certain order and called phases . This system, also a product of Tesla’s experiments, is extremely effective and therefore the most popular on the planet.
- Single phase current . It is obtained by taking a single phase of the three-phase current and a neutral cable, which allows to take advantage of the transmission of energy at a low voltage (230 volts). Although it is used in many countries because it is sufficient to operate appliances, many other devices that require high electrical power do not operate with it.
Electric current’s effects
Electric current is a versatile force, which offers mankind numerous practical uses, summarized in the following effects:
- Caloric . When transmitted by a material that offers resistance to its passage (a resistance), electricity generates an increase in caloric energy (heating), which can be used to heat spaces, cook, etc.
- Lumínicos . When the electrical resistance of a conducting wire is very large, the passage of electrons has an incandescent effect that generates heat and especially light. This is the principle of operation of the bulbs.
- Magnetics . Electric current produces magnets, since the generated electric field also produces a magnetic one, as in the case of electromagnets used in car scrap yards, or in electric compasses.
- Chemicals . Electricity also serves to cause changes in substances and catalyze (accelerate or make more effective) certain chemical reactions. This allows mechanisms such as electrolysis, which is useful for, for example:
- Protect metals from rust and corrosion.
- Breaking chemical bonds to obtain pure substances (such as oxygen and hydrogen from water).
- Melt certain metals (for gold plating, for example).
- Mechanical . Electricity provides the energy necessary to activate devices that carry out a specific job, as is the case of motors that generate movement, traction or speed.