The electrical conductors or conductive materials They are those that have little resistance to the circulation of electric current, given their specific properties. The atomic structure of the electrical conductors facilitates the movement of electrons through them, with which this type of elements favors the transmission of electricity..
Conductors can be presented in various forms, one of which is the material in specific physical conditions, such as metal bars (rods) that have not been made to form part of electrical circuits. Despite not being part of an electrical assembly, these materials always maintain their conductive properties.
There are also unipolar or multipolar electrical conductors, which are formally used as connecting elements for electrical circuits in residential and industrial settings. This type of conductor can be formed inside by copper wires or another type of metallic material, covered with an insulating surface..
In addition, depending on the circuit configuration, conductors for residential applications (thin) or cables for underground taps in electrical distribution systems (thick) can be differentiated..
For the purposes of this article, we will focus on the characteristics of conductive materials in their pure state; In addition, we will know which are the most used conductive materials today and why.
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Electrical conductors are characterized by not offering much resistance to the passage of electrical current through them, which is only possible thanks to their electrical and physical properties, which guarantee that the circulation of electricity through the conductor does not induce deformation or destruction. of the material in question.
The main electrical characteristics of electrical conductors are as follows:
Electrical conductors must have good electrical conductivity to fulfill their function of transporting electrical energy.
The International Electrotechnical Commission determined in mid-1913 that the electrical conductivity of copper in its pure state could serve as a reference to measure and compare the conductivity of other conductive materials..
Thus, the International Standard for Annealed Copper (International Annealed Copper Standard, IACS for its acronym in English).
The reference adopted was the conductivity of an annealed copper wire of one meter in length, and one gram of mass at 20 ° C, whose value is equal to 5.80 x 107 Ye-1. This value is known as 100% electrical conductivity IACS, and it is the benchmark for measuring the conductivity of conductive materials..
A conductive material is considered as such if it has more than 40% IACS. Materials that have a conductivity greater than 100% IACS are considered high conductivity materials..
The atomic structure allows the passage of electric current, since atoms have few electrons in their valence shell and, in turn, these electrons are detached from the nucleus of the atom.
The configuration described implies that a large amount of energy is not required for electrons to move from one atom to another, facilitating the movement of electrons through the conductor..
These types of electrons are called free electrons. Its disposition and freedom of movement throughout the atomic structure is what makes it conducive to the circulation of electricity through the conductor..
The molecular structure of the conductors is made up of a closely knit network of nuclei, which remains practically immobile due to its cohesion.
This makes the movement of electrons that are far away within the molecule conducive, since they move freely and react to the proximity of an electric field..
This reaction induces the movement of the electrons in a specific direction, which gives rise to the circulation of electric current passing through the conductive material..
Being subjected to a particular charge, conductive materials eventually reach a state of electrostatic equilibrium in which the movement of charges within the material does not occur..
Positive charges clump together at one end of the material and negative charges accumulate at the opposite end. The displacement of charges towards the surface of the conductor generates the presence of equal and opposite electric fields inside the conductor. Thus, the total internal electric field within the material is zero.
The electrical conductors must be malleable; that is, they must be able to deform without breaking.
Conductive materials are usually used in domestic or industrial applications, in which they must be subjected to bending and bending; therefore, malleability is an extremely important characteristic.
These materials must be resistant to wear, to withstand the conditions of mechanical stress to which they are usually subjected, coupled with high temperatures due to current circulation..
When used in a residential or industrial application or as part of the interconnected electrical supply system, the conductors must always be covered by a suitable insulating layer..
This outer layer, also known as an insulating jacket, is necessary to prevent the electrical current flowing through the conductor from coming into contact with people or objects around it..
There are different categories of electrical conductors and, in turn, in each category are the materials or media with the highest electrical conductivity.
By excellence, the best electrical conductors are solid metals, among which copper, gold, silver, aluminum, iron and some alloys stand out..
However, there are other types of materials or solutions that have good electrical conduction properties, such as graphite or saline solutions..
Depending on the way in which electrical conduction is carried out, it is possible to differentiate three types of materials or conductive media, which are detailed below:
This group is made up of solid metals and their respective alloys..
Metallic conductors owe their high conductivity to the clouds of free electrons that favor the circulation of electric current through them. Metals give up the electrons located in the last orbit of their atoms without investing greater amounts of energy, which makes the jump of electrons from one atom to another propitious.
On the other hand, the alloys are characterized by having a high resistivity; that is, they present a resistance proportional to the length and diameter of the conductor.
The most commonly used alloys in electrical installations are brass, a copper and zinc alloy; tinplate, an alloy of iron and tin; copper nickel alloys; and chromium nickel alloys.
These are solutions made up of free ions, which help ionic class electrical conduction..
Most of these types of conductors are present in ionic solutions, since electrolytic substances must undergo partial (or total) dissociation to form the ions that will be charge carriers..
Electrolytic conductors base their operation on chemical reactions and on the displacement of matter, which facilitates the movement of electrons through the circulation path enabled by free ions..
In this category are the gases that have previously been subjected to an ionization process, which enables the conduction of electricity through them..
Air itself acts as a conductor of electricity when, upon dielectric breakdown, it serves as a conductive medium for the formation of lightning and electric discharges..
It is highly used in overhead electrical transmission systems since, despite having a 35% lower conductivity when compared to annealed copper, its weight is three times lighter than the latter..
High voltage sockets are usually covered by an external surface of polyvinyl chloride (PVC), which prevents overheating of the conductor and isolates the passage of electrical current from the outside.
It is the metal most used as an electrical conductor in industrial and residential applications, given the balance it presents between its conductivity and price..
Copper can be used in conductors of low and medium gauge, with one or several wires, depending on the amperometric capacity of the conductor..
It is a material used in electronic assemblies of microprocessors and integrated circuits. It is also used to manufacture battery terminals for vehicles, among other applications..
The conductivity of gold is approximately 20% less than the conductivity of annealed gold. However, it is a very durable and corrosion resistant material..
With a conductivity of 6.30 x 107 Ye-1 (9-10% higher than the conductivity of annealed copper), it is the metal with the highest electrical conductivity known to date.
It is a very malleable and ductile material, with a hardness comparable to that of gold or copper. However, its cost is extremely high, so its use is not so common in the industry.
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