Do you want to know what electrical conductors are? Just read through this article on “What Is An Electrical Conductor” to get all the details you need.
This article will provide you with all the necessary information on electrical conductors.
To clarify your reading, I will begin with an overview that explains the word in other fields. Also, I will explain how conductors work.
Subsequently, in the next section, I will explain the conductivity of a conductor and the factors that affect it. Furthermore, the next section will contain the effects of current on conductors.
After this, I will discuss the force around a current-carrying conductor. Then, I will distinguish between a wire and a cable.
Furthermore, I will explain ohmic and non-ohmic conductors. After which, I will list the properties of a good conductor.
Lastly, I will answer some frequently asked questions on electrical conductors.
Electrical Conductor: Overview
Conductor as a word applies to various aspects of life. For example, it is used in music, transportation, heat, and electricity.
In music, a conductor directs musicians’ performances while presenting a piece of music. He/she uses a baton to organize the vocal and instrumental performances of the musicians.
In transport, the conductor checks and gives out tickets. The conductor also ensures that passengers are comfortable on trains, buses, or public transport.
However, some rapid transit systems employ the service of a conductor to open and close doors and make announcements.
Furthermore, conductors are used to transfer heat in the conduction method of heat transfer. In thermal (heat) applications, a conductor is any material that allows thermal (heat) to pass through it.
Particularly, this article explains conductors as applicable to electricity. For example, you need a conductor to transmit electricity from the generation plant to the users.
Also, conductors are the devices we use to connect our electrical appliances to the household electricity through the outlets. Moreover, a conductor connects all our electrical switches (DC and AC) to the electrical system.
Therefore, an electrical conductor is any material that allows electrical current to flow through it in one or more directions. It is used in any electrical system to transmit current from one point to another.
Conductors are mainly metals. Although, other materials or substances like seawater, lemon juice, graphites, etc., also conduct electricity.
Electrical Conductor: How Conductors Work
Every solid material has both valence and condition bands. According to the band theory, every electrical conducting material has no energy gap between the valence and conduction bands.
You can see this in the energy band diagram.
However, the conduction band overlaps the valence band in conductors. Hence, it allows current to flow through the material when you apply voltage, no matter how small the voltage is.
Furthermore, the outer electrons of the valence band are loosely attached to the atom. Hence, the electrons get excited when voltage is applied and move from the valence band to the conduction band.
Nevertheless, these electrons move freely in the conduction band. Thus, this results in an abundance of electrons in the conduction band.
Rather than travel in a straight line, these electrons move with a to-and-fro motion. Hence, their velocity is known as drift velocity.
Drift velocity is the reason behind the collision in the conduction band of a conductor. The more this collision occurs, the higher the resistance to the current flow in the conductor.
Therefore, when you apply a potential difference across a conductor, electrons flow from the point of lower concentration to the point of higher concentration.
On the other hand, current moves in the opposite of electrons. In other words, they move from the point of higher concentration to the point of lower concentration.
Electrical Conductor: Conductivity
The conductivity of a conductor is its ability to conduct electric current. It is the reciprocal of resistivity.
Every conductor has free electrons on its surface. These free electrons allow an electric current to pass through them easily.
Conductors conduct electricity as a result of these free electrons.
Also, these conductors have a level of impurities in them. Unlike semiconductors, adding impurities to a conductor will reduce its conductivity.
If you have impurities in a conductor, it will neither increase the number of electrons nor the quantity of charge in each electron. Instead, it will distort the crystal lattice and impede the drift velocity.
As a result, the mobility of the electrons will decrease, and the temperature will increase. This will create more resistance on the conductor, which will reduce conductivity.
The conductivity of a conductor relates to its length, cross-sectional area, and conductance. Also, it relates to the resistivity of the conductor.
G = σ * A/L.
Therefore, σ = L * G/A.
L = length of the conductor in meters.
A = cross-sectional area of the conductor.
G = conductance of the conductor.
σ = conductivity of the conductor.
Also, conductivity as a reciprocal of resistivity is expressed as σ = 1/ρ.
But, ρ = R * A/L.
Hence, σ = L/(R * A).
ρ = resistivity of the conductor.
R = resistance of the conductor in ohms.
The resistivity of a conductor is the rate at which a conductor resists the flow of current concerning its length and cross-sectional area. It can also be defined in terms of electric field and current density.
Hence, ρ = E/J.
E = magnitude of the electric field in volts per meter.
J = current density in amperes per meter square.
Electric Field is the field that is found around particles that are electrically charged. These charged particles also exert the force of attraction or repulsion on all other charged particles in the electric field.
Current density is the amount of electrical charge that flows through a given area of a chosen cross-section.
The resistance of a conductor is the degree to which the conductor opposes or impedes the flow of electric current through it. The SI unit of resistance is the ohm.
Good conductors have low resistance. However, from Ohm’s Law, resistance is defined as the ratio of potential difference (voltage) and current.
Mathematically, R = V/I.
V = potential difference across the conductor.
I = current flowing through the conductor.
This is the degree to which a conductor allows current flow. It is the reciprocal of resistance.
Mathematically, G = 1/R.
But, R = V/I.
Hence, G = I/V.
The SI unit of conductance is siemens or mhos.
Electrical Conductor: Factors That Affect The Conductivity Of A Conductor
Length Of The Conductor
An increase in the length of a conductor increases the resistance of that conductor as well as its resistivity. Hence, it reduces the conductivity of the conductor.
This is a result of the numerous collisions due to electron flow in the conductor. When an electron flows in a conductor, it collides with other atoms. This increases the temperature of the conductor.
Hence, it reduces conductivity and causes voltage drops along the conductor.
Cross-sectional Area Of The Conductor
A conductor with a larger cross-sectional area will conduct more current than a conductor with a small cross-sectional area. This is because a larger cross-section gives room for less collision among electrons.
Temperature Of The Conductor
When current flows through a conductor, it gradually heats up due to the movement and collisions of electrons. As the temperature increases, the resistance of the conductor also increases.
As a result, the conductivity of the material reduces.
Electrical Conductor: Effects Of Current On A Conductor
Temperature Rise Of The Conductor
As current flows through a conductor, the temperature rises due to the movement and collision of electrons. Thus, the resistance of the conductor increases, which in turn reduces the conductivity of the conductor.
Increase In The Length Of The Conductor
When current flows through a conductor, expansion occurs in the conductor. This is a result of the temperature rise.
Most conductors are metals, and one of the properties of a metal is that it is malleable (it can melt when heat is applied). Therefore, the temperature rise results from a heating effect in the conductor.
As a result, the conductor expands. However, the conductor tends to contrast when the current stops flowing and it gets cold, but it does not get back its original size.
This is due to the displacement of molecules while the current was flowing. Hence, it results in a little increase in the length of the conductor, which becomes obvious with time.
Gradually, the conductor increases in length and causes a sag in transmission and distribution lines. It also contributes to weakening the joint of a conductor.
Electromagnetic Field Around The Conductor
One of the effects of current on a conductor is that it creates a magnetic field around it. This magnetic field disappears when the current stops flowing through the conductor.
However, the magnetic field consists of lines of force in the shape of concentric circles around the conductor at each point throughout the length of the conductor.
Furthermore, this field tends to repel or attract magnets depending on the direction of the current flow. The density of the field depends on the magnitude of the current flowing through the conductor.
Electrical Conductor: Force On A Current Carrying Conductor
When an electrical current flows through a conductor, it produces a force that either repels or attracts a magnet. Thus, the force on a current-carrying conductor is a magnetic force.
In his experiment, H. C. Oersted concluded that every conductor carrying current has a magnetic field around it. However, this magnetic field disappears when the current passes through it.
Hence, a current-carrying conductor is a temporary magnet. Also, the direction of the current determines the direction of the magnetic lines of force.
However, the magnitude of the magnetic force around the conductor is determined by the magnetic field, the current flowing through the conductor, and the length of the conductor.
F = B * I * L.
F = magnetic force in Newtons.
B = magnetic field in webers per meter square.
I = magnitude of current passing through the conductor.
L = length of the conductor.
Two Parallel Conductors
Also, assuming you place two conductors in parallel to each other, there will be an interaction between their fields. Thus, a force will act between the two wires.
However, the magnitude of the force will be the same, but the directions will be the opposite.
If the currents in both conductors flow in the same direction, there will be a force of attraction between the conductors.
Also, if the currents flow in the opposite direction, the force between them will be repulsive.
Nevertheless, the force between both conductors is determined by the magnitude of the currents that flow through them, the conductors’ length, and their distance apart.
F/L = (μo * I1 * I2)/(2π * r).
F/L = force per unit length of the conductors in Newtons per meter (N/m).
μo = permeability of free space (4π x 10-7 N/A2).
I1 = current in conductor 1 in amperes.
I2 = current in conductor 2 in amperes.
r = distance between the conductors.
Electrical Conductor: Wire Vs. Cable
In the practical use of conductors, the words “wire” and “cable” are been used consistently and interchangeably. Sometimes without the understanding of their difference.
A cable is not the same as a wire. However, you either use a cable or a wire for electricity.
A wire is a single conductor clothed with an insulator that carries electricity from one point to another. Also, the conductor in a wire can either be a single-core or stranded.
Single-core wires have only one conductor, while the stranded wires have strands of conductors. The stranded conductor can be held together by twisting them.
A wire can be either insulated or bare. An insulated wire has a visible insulating material which could be cross-linked polyethylene (XLPE) or polyvinyl chloride (PVC).
The bare wire has no visible insulator. However, the air is its insulating material.
Types Of Electrical Wire
The solid wire has only one conductor protected by a colored sheath. It offers low resistance. Also, it is most preferred for higher frequencies.
This particular wire contains thin strands of conductors that are twisted together. As a result, they are flexible and more durable than solid wire. Also, it has a larger cross-sectional area compared to solid wire.
A cable is a group of wires coated with thin PVC layers. They bond together by twisting them and sheathed with outer insulation.
The cables’ classification depends on the cable’s number of wires and gauge.
Types Of Cables
Twisted Pair Cables
This consist of two cables that are twisted together. The twisting of the cables avoids the noise due to magnetic coupling.
Hence, it is useful in carrying signals. Twisted pair cables generally apply to data communication, networking, and telecommunication.
This cable has two or more conductors separated by insulation to protect signal integrity. You can also refer to them as balanced line configuration cables.
A coaxial cable consists of an inner conductor, and a parallel outer foil conductor surrounds it. An insulating layer protects it.
The coaxial cable uses an insulating dielectric to keep the two conductors from each other. A TV cable is a typical example of a coaxial cable.
Fibre Optic Cable
The fiber optic cable is a cable that transmits signals with the aid of a bunch of glass threads. Its bandwidth is greater than that of metal conductors. Thus, they can carry more information.
Electrical Conductor: Ohmic And Non-Ohmic Conductors
All electrical conductors are broadly classified into ohmic and non-ohmic conductors. This is because of the graphical relationship they possess between voltage and current.
Therefore, Ohmic conductors are all conductors and semiconductors that obey Ohm’s Law. While the non-ohmic conductors do not obey Ohm’s Law.
Electrical Conductor: Properties Of A Good Conductor
- They have very low or specific resistance.
- Also, they conduct electricity readily.
- Even so, they are good conductors of heat.
- They are malleable and ductile.
- Furthermore, they should not react to climatic conditions.
- In addition, the liquid should not corrode them.
- Their tensile strength must be high.
- More so, their cost must be low.
- Lastly, it must be readily available in plenty.
Frequently Asked Questions
It is any material or substance that allows current to pass through it.
Conductors allow an electric current to pass through them.
On the other hand, insulators do not allow an electric current to flow through them. They offer infinite resistance to current flow.
No. A battery is an active circuit device that offers DC to a circuit.
The good conductors include silver, gold, copper, aluminum, steel, mercury, iron, seawater, etc.
A conductor is a material whose outer electrons are not tightly bound. Hence, they can move through the material freely.
All metals can conduct electricity and heat. However, some are more useful than others.
Conductors only allow charges to flow through them. Therefore, they can not be charged.
Air consists of neutral and inert gases. Thus, it is a poor conductor of electricity.
Yes. Gold is a good conductor.
Electrical Conductor: My Final Thoughts
An electrical conductor is a reason we have electricity in our homes. They are the only materials that can transport electricity and signals.
However, not all conductors obey Ohms law. Hence, the non-ohmic has a nonlinear relationship between the voltage and current.
Even so, both wires and cables are good conductors. The difference is that a wire is just one conductor, and a cable is a group of wires.
Therefore, this article on electrical conductors has every information you require on conductors. In addition, it details the effects of current on conductors and the force that exists on current-carrying conductors.
Hence, if you have read this article, you have all the information you need on conductors.
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