PPT - Dielectric and Magnetic Properties of Materials - Civil Engineering (CE) PDF Download

 Page 1


1/15/2017 1
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
Engineering Physics II
Presentation by 
Dr.A K Mishra
Associate Professor
Jahangirabad Institute of Technology, Barabanki
Email:  akmishra.phy@gmail.com
Arun.Kumar@jit.edu.in
Page 2


1/15/2017 1
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
Engineering Physics II
Presentation by 
Dr.A K Mishra
Associate Professor
Jahangirabad Institute of Technology, Barabanki
Email:  akmishra.phy@gmail.com
Arun.Kumar@jit.edu.in
Dielectrics Introduction
• Dielectrics are basically nonconductors of electricity because     
usually  do not have any free charge for conduction.
• They have positive and negative charge tightly bound together.
• Under the influence of external field positive and negative 
charges are displaced from their equilibrium and form dipole 
which are responsible for dielectric behavior of these materials 
it may solid, liquid or gases.
• There is a slight difference between dielectric and insulators. 
The main function of dielectrics is to store electrical energy, 
while the function of insulators is to obstruct the flow of 
current.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
2
Page 3


1/15/2017 1
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
Engineering Physics II
Presentation by 
Dr.A K Mishra
Associate Professor
Jahangirabad Institute of Technology, Barabanki
Email:  akmishra.phy@gmail.com
Arun.Kumar@jit.edu.in
Dielectrics Introduction
• Dielectrics are basically nonconductors of electricity because     
usually  do not have any free charge for conduction.
• They have positive and negative charge tightly bound together.
• Under the influence of external field positive and negative 
charges are displaced from their equilibrium and form dipole 
which are responsible for dielectric behavior of these materials 
it may solid, liquid or gases.
• There is a slight difference between dielectric and insulators. 
The main function of dielectrics is to store electrical energy, 
while the function of insulators is to obstruct the flow of 
current.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
2
Dielectric Constant
• Michel faraday discovered that the capacitance of a capacitor 
increased if the space between the conductors plates is filled with a 
dielectric materials.
• If         is the capacitance of the condenser filled with air between its 
plates. 
• C is the capacitance when the space filled with dielectric materials.
Then dielectric constant defined as 
K =         =        …………………….(1)             
Where        is known as 
relative permittivity or dielectric constant, of the medium.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
3
0
C
r
?
r
?
0
C
C
Page 4


1/15/2017 1
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
Engineering Physics II
Presentation by 
Dr.A K Mishra
Associate Professor
Jahangirabad Institute of Technology, Barabanki
Email:  akmishra.phy@gmail.com
Arun.Kumar@jit.edu.in
Dielectrics Introduction
• Dielectrics are basically nonconductors of electricity because     
usually  do not have any free charge for conduction.
• They have positive and negative charge tightly bound together.
• Under the influence of external field positive and negative 
charges are displaced from their equilibrium and form dipole 
which are responsible for dielectric behavior of these materials 
it may solid, liquid or gases.
• There is a slight difference between dielectric and insulators. 
The main function of dielectrics is to store electrical energy, 
while the function of insulators is to obstruct the flow of 
current.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
2
Dielectric Constant
• Michel faraday discovered that the capacitance of a capacitor 
increased if the space between the conductors plates is filled with a 
dielectric materials.
• If         is the capacitance of the condenser filled with air between its 
plates. 
• C is the capacitance when the space filled with dielectric materials.
Then dielectric constant defined as 
K =         =        …………………….(1)             
Where        is known as 
relative permittivity or dielectric constant, of the medium.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
3
0
C
r
?
r
?
0
C
C
continued
•If a parallel plate capacitor with metal plates of area A and separation d, then its capacity  
can be expressed as 
……………..(2)  
Where        is the permittivity of free space between the plates of the capacitor.  
If the space filled with dielectric material of permittivity       then the capacitance of the      
same capacitor will be given as
………………….(3) 
where K is constant having its value more than unity and it is also known as relative 
permittivity (      ). Now equation (3) can be written as                                                                    
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
4
d
C
0
0
A      
?
?
0
?
?
0
K   
?
? ?
r
?
d
   
A
C
?
?
Page 5


1/15/2017 1
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
Engineering Physics II
Presentation by 
Dr.A K Mishra
Associate Professor
Jahangirabad Institute of Technology, Barabanki
Email:  akmishra.phy@gmail.com
Arun.Kumar@jit.edu.in
Dielectrics Introduction
• Dielectrics are basically nonconductors of electricity because     
usually  do not have any free charge for conduction.
• They have positive and negative charge tightly bound together.
• Under the influence of external field positive and negative 
charges are displaced from their equilibrium and form dipole 
which are responsible for dielectric behavior of these materials 
it may solid, liquid or gases.
• There is a slight difference between dielectric and insulators. 
The main function of dielectrics is to store electrical energy, 
while the function of insulators is to obstruct the flow of 
current.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
2
Dielectric Constant
• Michel faraday discovered that the capacitance of a capacitor 
increased if the space between the conductors plates is filled with a 
dielectric materials.
• If         is the capacitance of the condenser filled with air between its 
plates. 
• C is the capacitance when the space filled with dielectric materials.
Then dielectric constant defined as 
K =         =        …………………….(1)             
Where        is known as 
relative permittivity or dielectric constant, of the medium.
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
3
0
C
r
?
r
?
0
C
C
continued
•If a parallel plate capacitor with metal plates of area A and separation d, then its capacity  
can be expressed as 
……………..(2)  
Where        is the permittivity of free space between the plates of the capacitor.  
If the space filled with dielectric material of permittivity       then the capacitance of the      
same capacitor will be given as
………………….(3) 
where K is constant having its value more than unity and it is also known as relative 
permittivity (      ). Now equation (3) can be written as                                                                    
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
4
d
C
0
0
A      
?
?
0
?
?
0
K   
?
? ?
r
?
d
   
A
C
?
?
continued
From equation (2) & (4)
…………………..(5)
1/15/2017
Dr A K Mishra, Academic Coordinator,        
JIT Jahangirabad
5
0 0
   
C
    
?
?
?
? ? ?
C
r
K
d
A 
   
0
? K
C ?
d
C
r
A
0
   
    
?
?
?