Inductors

An inductor has been defined as a physical device which capable of storing energy by virtue of current flowing through it.
An indouctor is a circuit component 

results from the magnetic field around a current-carrying conductor; the electric current through the conductor creates a magnetic flux. Mathematically speaking, inductance is determined by how much magnetic flux φ through the circuit is created by a given current i^[1][2][3][4]

${\displaystyle L={\phi \over i}}$        (1)

Inductors that have ferromagnetic cores are nonlinear; the inductance changes with the current, in this more general case inductance is defined as

${\displaystyle L={d\phi \over di}\,}$

Constitutive equation[edit]

Any change in the current through an inductor creates a changing flux, inducing a voltage across the inductor. By Faraday's law of induction, the voltage induced by any change in magnetic flux through the circuit is

From (1) above^[4]

${\displaystyle v={d \over dt}(Li)=L{di \over dt}\,}$   

Types of inductor

1. Air Core Inductors
• In this type of inductor, core is completely absent. These inductors offer high reluctance path for the magnetic flux, hence less inductance. The air core inductors have larger coils to produce higher flux densities. These are used in high frequency applications including TV and radio receivers.
  
2.  Ferro Magnetic or Iron Core Inductors
• These are the different types of inductors which offer advantages of decreased cost and low core losses at high frequencies. Ferrite is a metal oxide ceramic based around a mixture of Ferric Oxide Fe2O3. Soft ferrites are used for the core construction to reduce the hysteresis losses.
  
3. Bobbin based Inductors
• In this type, coil is wounded on the bobbin. Bobbin wound inductor designs vary widely in terms of power rating, voltage and current levels, operating frequency, etc. These are mostly used in switch mode power supplies and power conversion applications.
  
4. Multi Layer Inductors
• A multilayer inductor contains two conductive coil patterns which are arranged in two layers in the upper part of a multi-layered body. The coils are connected electrically in a consecutive manner in series to two more conductive coil patterns disposed in the lower part of the multi-layered body. These are mainly used in mobile communication systems and noise suppression applications.
  
5. Thin Film Inductors


• These are completely different from the conventional chip-type inductors wound with copper wire. In this type, tiny inductors are formed using thin-film processing to create the chip inductor for high-frequency applications, which ranges from about nano Henry.