We explain what electric current is and what electrical intensity is. Also, the types of electric current and their effects.
What is electric current?
Electric current is called flow of electric charge through a conductive material due to the displacement of the electrons that orbit the nucleus of the atoms that make up the conductor.
This movement of particles begins once an external voltage, such as a battery, for example, is applied to the ends of the conductor. This voltage generates an electric field on the electrons that, having a negative charge, are attracted to the positive terminal.
To be transmitted, the electric current requires materials that have a large share of free electrons that is, located in their last orbit around the nucleus and, therefore, susceptible to movement as they are less strongly attracted to it.
In this sense, a distinction can be made between conductive, semiconductor and insulating materials, according to their ability to transmit electric current (good, little and zero, respectively).
The first experiments with electricity were in the 18th century and only had electrical charges obtained by friction (static) or by induction. We had to wait until 1800 to verify the constant movement of an electric charge, when the Italian physicist Alessandro Volta invented the electric battery.
See also: Magnetism
Intensity
This name refers to the electric current flow that is, the amount of electrical charge that passes through a conductive material per unit of time. The flow of electric current can be compared to the amount of water in a river, capable of moving charges and carrying out a quantity of work.
According to the International System (SI), this intensity It is normally measured in Coulombs per second (C/s) which is equivalent to an ampere (A), a basic unit in the field of electricity and in 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
Depending on its nature, electric current can be of several types:
- Direct current (DC). Also called direct current (DC), it consists of a flow of electrical charges that does not change its direction over time, that is, it is produced based on a difference in electric potential (voltage) whose highest and lowest potential terminals are not interchangeable. In other words, its direction of circulation is always the same.
- Alternating current (AC) Unlike direct current, it is an electric current whose direction and direction varies cyclically. This current is mathematically described by sine waves and in energy terms it is much more efficient than direct current, which is why homes and businesses receive it. It was invented by Nikola Tesla at the end of the 19th century.
- Three-phase current 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 efficient 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 taking 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 household appliances, many other devices that require high electrical power do not operate with it.
Effects of electric current
Electric current offers humanity an enormous number of practical uses:
- Calories When heat is transmitted through a material that offers resistance to its passage, resistance is generated (no material is perfect, some have more resistance than others). This resistance dissipates heat that can be used to heat spaces, cook, etc.
- Luminous When the electrical resistance of a conductive wire is very low, a large number of electrons circulate through it, generating heat and, above all, light. This is the working principle of light bulbs.
- Magnetic Electric current generates magnetic fields, as in the case of electromagnets used in car scrapyards or in electric compasses.
- Chemicals Electricity is used to cause changes in substances and catalyze (accelerate or make more effective) certain chemical reactions. This allows mechanisms such as electrolysis, the process that separates the elements of a compound through electricity and is useful for, for example:
- Protect metals from rust and corrosion.
- Break chemical bonds to obtain pure substances (such as oxygen and hydrogen from water).
- Melting certain metals (for gold plating, for example).
- Mechanics. Electricity provides the energy necessary to activate devices that carry out specific mechanical work, such as motors that generate movement, traction or speed.
