If the number of turns increases, the inductance will increase. If the cross-sectional area increases, the
inductance will increase. If the core material is changed, the inductance will change directly in proportion to
the permeability of the core material. The permeability of the core is a measure of the cores ability to
conduct magnetic lines of flux, as compared with that of air. If these three factors remain constant and the
length of the coil changes, the inductance will vary inversely; that is, the length increases, the inductance
The inductance of a coil is determined by four factors:
(1) the number of turns of wire in the coil (N),
(2) the cross-sectional area of the coil (A),
(3) the length of the coil (1), and
(4) ___________________________________ ?
Select the definition of an inductor.
a. It is a coil with an undetermined amount of inductance.
b. It is a coil with an undetermined amount of resistance.
c. It is a coil with a specific amount of resistance.
d. It is a coil with a specific amount of inductance.
What is the symbol for inductance?
The formula for the inductance of a coil is
Permeability () of the core plays an important role in the construction of an inductor. Iron is commonly
used as a core material for inductors, because iron has a much higher permeability than air. The symbols
for air-core and iron-core inductors are shown below. Which of the coils has the highest value of
inductance, assuming that the only difference is the type of core material used?