Today you will know an important component in the field of Electronics and Electricals, the Inductor how it looks like you can see in the image.1 there are many types of inductors. An inductor is a passive two-terminal component that temporarily stores energy in the form of a magnetic field. It is usually called a coil. The main property of an inductor is that it opposes any change in current.

What is Inductor?

Image.1

Type of inductor

The inductor is a conductor wrapped over a medium such as air core, Iron, non-magnetic, and variable core, like coil, is called Inductor.

As we discuss in the above line, an inductor is a passive component that is used in most power electronic circuits to store energy in the form of magnetic energy, According to Faraday’s law of Electromagnetic induction, When the current flowing through an inductor change, the time-varying magnetic field induces a voltage in the conductor. According to lens law, the direction of induced EMF opposes the change in current that created it. Hence, induced EMF is opposite to the voltage applied across the coil. the is One of the most important properties of an inductor. Whenever the current flows across the inductor changes it either acquires charge or loses the charge to equalize the current passing through it. 

Inductors are mostly used to decrease or control the electric spikes by storing energy temporarily in an electromagnetic field and then releasing it back into the circuit. The inductor is also called a reactor, choke, or coil.

It is described by its distinctive nature of inductance, which is defined as the ratio of the voltage to the rate of change of current. Inductance is a result of the induced magnetic field on the coil. It is also determined by several factors such as; 

       1. The shape of the coil. 

       2. The number of turns and layers of the wire. 

       3. The space that is given between the turns.

       4. Permeability of the core material.

       5. The size of the core.

The S.I. unit of inductance is henry (H) and when we measure magnetic circuits it is equivalent to weber/ampere. It is denoted by the symbol L.

Meantime, an inductor is all most totally different from a capacitor. In the case of a capacitor, it stores energy as electrical energy but an inductor stores energy in the form of magnetic energy. One other feature of the inductor is that it also changes its polarity while discharging. In this way polarity during discharging can be made opposite to the polarity during charging. The polarity of the induced voltage is well explained by 

Overvewis of Lenz low

The induced electromotive force with different polarities induces a current whose magnetic field opposes the change in magnetic flux through the loop to ensure that original flux is maintained through the loop when current flows in it.

Image.2

Symbols of Inductor

 

 Types of Inductors

Depending on the type of material used inductors can be classified as below.

1. Iron Core Inductor
2. Air Core Inductor
3. Iron Powder Inductor
4. Ferrite Core Inductor

Iron Core Inductor

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A conductor which is wrapped over an Iron, like a coil, is called an Iron core Inductor. These inductors are low space inductors that have high power and high inductance value. so, they are limited in high-frequency capacity which is why these types of inductors are used in audio equipment.

Air Core Inductor

Image.4

These inductors, a conductor wrapped over a without physical core, is called an air core Inductor. are used when the amount of inductance required is low. Since there is no core, it does not have a core loss. But the number of turns the inductor always has more than the core inductor in parameter. This results in a high-Quality factor. Usually, ceramic inductors are often referred to as air-core inductors.

Iron Powder Inductor

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This type of inductor, wrapped over an iron Oxide. They are formed by very fine and insulating particles of pure iron powder. High magnetic flux can be stored in it due to the air gap Iron Oxide. The permeability of the core of this type of inductor is very less. They are usually below 100. They are mainly used in switching power supplies circuits.

Ferrite Core Inductor

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In this type of Inductor, wrapped over ferrite materials are used as core. The general composition of ferrites is XFe2O4. Where X represents transition material. Ferrites can be classified into two types. Soft ferrites and hard ferrites.

1. Soft Ferrite: Materials that have the ability to reverse their polarity without any external energy.

1. Hard Ferrite: These are permanent magnets. That is their polarity will not change even when the magnetic field is removed.

Use of an Inductor

1. To control signals.

1. To store energy.

Inductors can be used for two primary works.

Controlling Signals

Coils in an inductor can be used to store energy. The work of the inductor depends upon the frequency of the current passing through it. That is for higher frequency signals will be passed less easily and conversely. This work tells that it blocks AC Current and passes DC Current. Hence, it can be used to block AC signals, which means we can use it as a DC filter.

Inductors can be used along with capacitors to form LC filters.

Storing Energy
Inductors In Parallel connection

Inductor stores energy in the form of magnetic energy. Coils can store electrical energy in a form of magnetic energy using the property that an electric current flowing through a coil produces a magnetic field, which is coils offer a means of storing energy based on inductivity.

 We know that when resistors are connected in parallel, their effective resistance decreases. which are we already take about it? 

here also Similarly, when inductors are connected in parallel form, their effective inductance decreases.

Image.7

 

Here, the current flowing through each inductor will be different. This current depends upon the inductance value. However, the voltage across each conductor will be the same. inductor also flows the Kirchoff’s Current law total current is the sum of the current through each branch. 

That is

IT = I1 + I2 +I3

We know that the voltage across an inductor is given by the equation.

                      V = L di / dt

We can write.

                      vAB = LTotal x dit / dt

                      VAB = LTotal x d (I1 + I2 + I3) / dt

Now we can write it as.

                      vAB = LTotal x dl1 / dt + LTotal x dl2 / dt + LTotal x dl3 / dt

That is.

                       vAB = LTotal ( V / L1 + V / L2 + V / L3 )

Since voltage are equal we can simplify the equation as,

                       1 / LTota = 1 / L1 + 1 / L2 + 1 / L3

Inductors In Series

When they are connected end to end, then the inductors are said to be in a series connection. We know that when resistors are connected in series, their effective resistance increases.

Similarly, when inductors are connected in series, their effective inductance increases.

To get the total inductance is very easy. You only have to add every inductance. That is when inductors are connected in series, the total inductance is the sum of all inductance.

 

Here are three inductors, and are connected in series. In this case, the current flowing through each inductor is the same while the voltage across each inductor is different. This voltage depends upon the inductance value. Here inductor also flows the Kirchoff’s voltage law total voltage drop is the sum of the voltage drop across each inductor. 

That is.

                     VT = V1 + V2 +V3

We know that the voltage across an inductor is given by the equation.

                     V = L di / dt

So here we can write as.

                     LTotal dl / dt = L1 x dl1 / dt + L2 x dl2 / dt + L3 x dl3 / dt

                     But

                     I = I1 = I2 = I3

Therefore.

                     L dl / dt = L1 x dl / dt + L2 x dl / dt + L3 x dl / dt

                     LTotal = L1 + L2 + L3

Energy Stored In An Inductor

When a current passes through an inductor an emf is induced in it. This back emf opposes the flow of current through the inductor. So to establish a current in the inductor work has to be done against this emf by the voltage source.

Consider a time interval dt.

During this period, work done dW is given by

                      dW = Pdt = – Eidt = iL di / dt x dt = Lidi

To find the total work done the above expression must be integrated.

                       W = 0∫ILidi = ½ LI2

Therefore energy stored in an inductor is given by the equation,

                       W = ½ LI2

The impedance of an Inductor

AC resistance mostly determines the opposition of current flowing through a coil. This AC resistance is most commonly known as impedance. In this section, since we are discussing the opposition given by the inductor, this can be called Inductive Reactance. Inductive reactance which is given the symbol XL is the property in an AC circuit that opposes the change in the current.

It is given by the equation that is.

                          XL = VL / IL = Lω

From the equation, it is clear that inductive reactance is proportional to frequency.

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Summery

In this post we disscused about of inductor their type and work.

• What is Inductor?

         Type of Inductor

1. Iron Core Inductor
2. Air Core Inductor
3. Iron Powder Inductor
4. Ferrite Core Inductor

We will know more about other topic in next post thank for visit here.