INDUCTORS &
INDUCTORS &
INDUCTANCE
INDUCTANCE
ChaPtE
ChaPtE
R 7 :
R 7 :

SCOPE
OF
STUDY
SCOPE
OF
STUDY
7 main sub topics that you should learn and understand are :
Faraday’s
Law
Len’z
Law
Induction
Inductors and Inductance
Energy Stored in Magnetic Field
RL Circuit
LC Circuit

FARADAY’S
LAW
FARADAY’S
LAW
DEFINITION
The emf induced in a circuit is equal to the rate
of change of magnetic flux through the circuit
The emf induced in a circuit is equal to the rate
of change of magnetic flux through the circuit

FARADAY’S
LAW
FARADAY’S
LAW
EQUATION
emf, ε = ∆
Φ
B
∆t
emf, ε = N∆
Φ
B
∆t
where :
Φ
B
= magnetic flux
t = time
N = number of loops

FARADAY’S
LAW
FARADAY’S
LAW
Φ
B
= B . A
= BA cos
ϴ
Magnetic flux (Wb @ Tm
2
)
Magnetic field (Tesla,T)
Area (m
2
)
Angle between B and A

FARADAY’S
LAW
FARADAY’S
LAW

FARADAY’S
LAW
FARADAY’S
LAW
Changing magnetic flux produces an emf
(or changing B-Field produces E-Field)
The rate of change of magnetic flux is
required

FARADAY’S
LAW
FARADAY’S
LAW
Magnetic field around a permanent magnet.
B

FARADAY’S
LAW
FARADAY’S
LAW
Interaction of two permanent bar magnets.

FARADAY’S
LAW
FARADAY’S
LAW
Bar magnet moves through coil
Current induced in coil
v
S
N
Change pole that enters
Induced current changes sign
v
N
S
Bar magnet stationary inside coil
No current induced in coil
N
S

FARADAY’S
LAW
FARADAY’S
LAW
Coil moves past fixed bar magnet
Current induced in coil
v
S
N
a
b
Switch closed (or opened)
current induced in coil b
Steady state current in coil a
no current induced in coil b

FARADAY’S
LAW
FARADAY’S
LAW
•Conclusion:A current is induced in a loop when:

FARADAY’S
LAW
FARADAY’S
LAW
Faraday's law
in

FARADAY’S
LAW
FARADAY’S
LAW

#### You've reached the end of your free preview.

Want to read all 57 pages?

- Fall '15
- Junaidah
- Inductance, Magnetism, Energy , Inductor Notes