PPT: Dielectrics | Electromagnetic Fields Theory (EMFT) - Electrical Engineering (EE) PDF Download

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Dielectrics Dielectrics
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Dielectrics Dielectrics
Dielectrics are the materials having electric dipole moment Dielectrics are the materials having electric dipole moment permantly permantly. .
Dipole: Dipole: A dipole is an entity in which equal positive and negative A dipole is an entity in which equal positive and negative
charges are separated by a small distance.. charges are separated by a small distance..
DIPOLE moment (µ
ele
):The product of magnitude of either of the
charges and separation distance b/w them is called Dipole moment.
µ
e
= q . x à coul – m
All dielectrics are electrical insulators and they are mainly used to store All dielectrics are electrical insulators and they are mainly used to store
electrical energy. electrical energy.
Ex: Mica, glass, plastic, water & polar molecules… Ex: Mica, glass, plastic, water & polar molecules…
X
q -q
Introduction
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Dielectrics Dielectrics
Dielectrics are the materials having electric dipole moment Dielectrics are the materials having electric dipole moment permantly permantly. .
Dipole: Dipole: A dipole is an entity in which equal positive and negative A dipole is an entity in which equal positive and negative
charges are separated by a small distance.. charges are separated by a small distance..
DIPOLE moment (µ
ele
):The product of magnitude of either of the
charges and separation distance b/w them is called Dipole moment.
µ
e
= q . x à coul – m
All dielectrics are electrical insulators and they are mainly used to store All dielectrics are electrical insulators and they are mainly used to store
electrical energy. electrical energy.
Ex: Mica, glass, plastic, water & polar molecules… Ex: Mica, glass, plastic, water & polar molecules…
X
q -q
Introduction
POLARISATION OF DIELECRICS POLARISATION OF DIELECRICS
nn When we are applying external electric field, it causes the When we are applying external electric field, it causes the
electron cloud to move away. Thus the centroides of the electron cloud to move away. Thus the centroides of the
positive and negative charges now no longer coincides and as a positive and negative charges now no longer coincides and as a
result of that an electric dipole is induced in the atom. Thus, result of that an electric dipole is induced in the atom. Thus,
atom is said to be polarize atom is said to be polarized. d.
nn Polarization : the process of creating or inducing dipoles  in a Polarization : the process of creating or inducing dipoles  in a
dielectric medium by an external field. dielectric medium by an external field.
nn On the basis on that dielectrics are the material that have On the basis on that dielectrics are the material that have
either permanent diploes or induced  in the presence of either permanent diploes or induced  in the presence of
external electric field . external electric field .
nn They are classified into two categories (1) Non polar (2)polar They are classified into two categories (1) Non polar (2)polar
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Dielectrics Dielectrics
Dielectrics are the materials having electric dipole moment Dielectrics are the materials having electric dipole moment permantly permantly. .
Dipole: Dipole: A dipole is an entity in which equal positive and negative A dipole is an entity in which equal positive and negative
charges are separated by a small distance.. charges are separated by a small distance..
DIPOLE moment (µ
ele
):The product of magnitude of either of the
charges and separation distance b/w them is called Dipole moment.
µ
e
= q . x à coul – m
All dielectrics are electrical insulators and they are mainly used to store All dielectrics are electrical insulators and they are mainly used to store
electrical energy. electrical energy.
Ex: Mica, glass, plastic, water & polar molecules… Ex: Mica, glass, plastic, water & polar molecules…
X
q -q
Introduction
POLARISATION OF DIELECRICS POLARISATION OF DIELECRICS
nn When we are applying external electric field, it causes the When we are applying external electric field, it causes the
electron cloud to move away. Thus the centroides of the electron cloud to move away. Thus the centroides of the
positive and negative charges now no longer coincides and as a positive and negative charges now no longer coincides and as a
result of that an electric dipole is induced in the atom. Thus, result of that an electric dipole is induced in the atom. Thus,
atom is said to be polarize atom is said to be polarized. d.
nn Polarization : the process of creating or inducing dipoles  in a Polarization : the process of creating or inducing dipoles  in a
dielectric medium by an external field. dielectric medium by an external field.
nn On the basis on that dielectrics are the material that have On the basis on that dielectrics are the material that have
either permanent diploes or induced  in the presence of either permanent diploes or induced  in the presence of
external electric field . external electric field .
nn They are classified into two categories (1) Non polar (2)polar They are classified into two categories (1) Non polar (2)polar
Dielectrics Dielectrics
nn Non Polar Dielectrics : Non Polar Dielectrics : There is no permanent There is no permanent
dipole existence in the absence of an electric field . dipole existence in the absence of an electric field .
nn Centroids Centroids of positive and negative charges of molecules of positive and negative charges of molecules
constituting the dielectric material coincide . constituting the dielectric material coincide .
nn Examples :H Examples :H2, 2, NN2, 2, OO2, 2, CO CO 22
nn Polar Dielectrics : Polar Dielectrics : there is permanent dipole exists there is permanent dipole exists
even in the absence of an electric field . even in the absence of an electric field .
nn Centroids Centroids of of posistive posistive and negative charges of molecules and negative charges of molecules
constituting  the dielectric material do not constituting  the dielectric material do not coinside coinside even in the even in the
absence of electric field absence of electric field
nn Examples : HCL , CO Examples : HCL , CO
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Dielectrics Dielectrics
Dielectrics are the materials having electric dipole moment Dielectrics are the materials having electric dipole moment permantly permantly. .
Dipole: Dipole: A dipole is an entity in which equal positive and negative A dipole is an entity in which equal positive and negative
charges are separated by a small distance.. charges are separated by a small distance..
DIPOLE moment (µ
ele
):The product of magnitude of either of the
charges and separation distance b/w them is called Dipole moment.
µ
e
= q . x à coul – m
All dielectrics are electrical insulators and they are mainly used to store All dielectrics are electrical insulators and they are mainly used to store
electrical energy. electrical energy.
Ex: Mica, glass, plastic, water & polar molecules… Ex: Mica, glass, plastic, water & polar molecules…
X
q -q
Introduction
POLARISATION OF DIELECRICS POLARISATION OF DIELECRICS
nn When we are applying external electric field, it causes the When we are applying external electric field, it causes the
electron cloud to move away. Thus the centroides of the electron cloud to move away. Thus the centroides of the
positive and negative charges now no longer coincides and as a positive and negative charges now no longer coincides and as a
result of that an electric dipole is induced in the atom. Thus, result of that an electric dipole is induced in the atom. Thus,
atom is said to be polarize atom is said to be polarized. d.
nn Polarization : the process of creating or inducing dipoles  in a Polarization : the process of creating or inducing dipoles  in a
dielectric medium by an external field. dielectric medium by an external field.
nn On the basis on that dielectrics are the material that have On the basis on that dielectrics are the material that have
either permanent diploes or induced  in the presence of either permanent diploes or induced  in the presence of
external electric field . external electric field .
nn They are classified into two categories (1) Non polar (2)polar They are classified into two categories (1) Non polar (2)polar
Dielectrics Dielectrics
nn Non Polar Dielectrics : Non Polar Dielectrics : There is no permanent There is no permanent
dipole existence in the absence of an electric field . dipole existence in the absence of an electric field .
nn Centroids Centroids of positive and negative charges of molecules of positive and negative charges of molecules
constituting the dielectric material coincide . constituting the dielectric material coincide .
nn Examples :H Examples :H2, 2, NN2, 2, OO2, 2, CO CO 22
nn Polar Dielectrics : Polar Dielectrics : there is permanent dipole exists there is permanent dipole exists
even in the absence of an electric field . even in the absence of an electric field .
nn Centroids Centroids of of posistive posistive and negative charges of molecules and negative charges of molecules
constituting  the dielectric material do not constituting  the dielectric material do not coinside coinside even in the even in the
absence of electric field absence of electric field
nn Examples : HCL , CO Examples : HCL , CO
+
Electric field
Dielectric atom
+
+
+
+
+
+
+
+
_
_
_
_
_
_
_
_
_
dipole