Inductor
Inductor is an electrical component that stores energy in magnetic field.
The inductor is made of a coil of conducting wire.
In an electrical circuit schematics, the inductor marked with the letter L.
The inductance is measured in units of Henry [L].
Inductor reduce current in AC circuits and short circuit in DC circuits.
Inductor picture
Inductor symbols
Inductor 

Iron core inductor 

Variable inductor 
Inductors in series
For several inductors in series the total equivalent inductance is:
L_{Total} = L_{1}+L_{2}+L_{3}+...
Inductors in parallel
For several inductors in parallel the total equivalent inductance is:
Inductor's voltage
Inductor's current
Energy of inductor
AC circuits
Inductor's reactance
X_{L} = ωL
Inductor's impedance
Cartesian form:
Z_{L} = jX_{L} = jωL
Polar form:
Z_{L} = X_{L}∠90º