Inductor

• Inductor is a passive element. Inductance (L) is a property of the inductor by which it stores electrical energy by means of electromagnetic stress. Inductance is measured in Henry. According the Faraday’s law if electromagnetic induction, the emf induced across the inductor is expressed by

$\small V=\frac{d\psi}{dt}$                                 (12)

• As we know, the flux (Ѱ) in the inductor is propostrional to the inductance and the current i flowing through it and expressed by

$\psi$=Li                                      (13)

• Substituting the equation (13) in (12) we get,

$v=L\frac{dl}{dt}$                                (14)

And   $i=\frac1L\int vdt$                 (15)

• Equation (14) and (15) are the parametric equations of an inductor.

Series and Parallel Connections of Inductors:

• Two or more inductors can be connected in series or parallel as shown in figure 1.5.

Diagram copy paste problem

• If L1, L2 and Ln inductors  are connected in series as shown in figue 1.5 (a), the equivalent inductance L is expressed by

$L=L_1+L_2+...+L_n$           (16)

• If L1, L2 and Ln inductors are connected in parallel as shown in figue 1.5 (b), the equivalent inductance L is expressed by

$\frac1L=\frac1{L_1}+\frac1{L_2}+...+\frac1{Ln}$        (17)

• If two inductors L1 and L2 are connected in parallel, then the equivalent inductance is expressed by

$\frac1L=\frac1{L_1}+\frac1{L_2}$
$L=\frac{L_1L_2}{L_1+L_2}$​​​​​​​