Inductor & Inductance

Inductor 

• If several number of turns are wound over the core, it is generally called as Inductor. 

• There are no power loss in the pure inductor. 
• The core of magnetic material has negligible loop area is used in order to make inductor. 
• The core magnetic material is made of thin laminations in order to reduce eddy current loss in the inductor or we can say that core material has high resistivity.

Equation of inductor

• Let us consider that a coil is made of N number of turns. 
• If current I flows through coil, flux Φ weber produced in it. This flux links with N number of turns.
• Flux linkage = N Φ
• Inductance L = N Φ / I
• Flux Φ = BA
• Therefore inductance L = N BA / I……… ( 1 )
• Flux density B = µH

                                = µ₀ µ_rH ……… ( 2 )

From equation ( 1 ) and ( 2 )

L = N ( µ₀ µ_rH ) A / l

   = N ( µ₀ µ_rH ) A / l

    = ( µ₀ µ_r )NHA / I

Putting H = NI / L

             L = ( µ₀ µ_r )( N²A ) / L

L = ( µ0 µr )( N2A ) / L

• We can say that the inductance depends upon number of turns and permeability of the core. 
• If the area and length of core is constant, the inductance is directly proportional to square of number of turns.

                                              L α ( N² )

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