Electrical circuits lecture notes b. Tech

 
H=
𝑀𝑀𝐹
𝐿𝐸𝑁𝐺𝑇𝐻
=
𝑁𝐼
𝑙
 
2.
The unit of magnetic field strength is AT/m 
Magnetic flux density(B) 
1.
 
The magnetic flux density in any material is defined as the magnetic flux established per 
unit area of cross-section.
 
𝐵 =
𝐹𝐿𝑈𝑋
𝐴𝑅𝐸𝐴 𝑂𝐹 𝐶𝑅𝑂𝑆𝑆 𝑆𝐸𝐶𝑇𝐼𝑂𝑁
=
∅
𝐴
2.The unit of 
magnetic flux density is wb/m
2
or TESLA
 
Relative permeability 
1.
 
It is defined as the ratio of flux density established in magnetic material to the flux 
density established in air or vacuum for the same magnetic field strength.
 
 
INTRODUCTION TO ELECTROMAGNETIC INDUCTION:: 
When a conductor moves in a magnetic field, an 
EMF
is generated; when it 
carries current in a magnetic field, a force is produced. Both of these effects may 
be deduced from one of the most fundamental principles of electromagnetism, 
and they provide the basis for a number of devices in which conductors move 
freely in a magnetic field. It has already been mentioned that most electrical 
machines employ a different form of construction. 
 
FARADAY'S LAW OF ELECTROMAGNETIC INDUCTION:
In 1831, Michael Faraday, an English physicist gave one of the most basic laws of 
electromagnetism called 
Faraday's law of electromagnetic induction
. This law explains the 
working principle of most of the electrical motors, generators, electrical 
transformers and inductors. This law shows the relationship between electric 
circuit and magnetic field. 
FARADAY'S FIRST LAW 
Any change in the magnetic field of a coil of wire will cause an emf to be induced in the coil. 
This emf induced is called induced emf and if the conductor circuit is closed, the current will 
also circulate through the circuit and this current is called induced current.
Method to change magnetic field: 

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