The document discusses electrical properties and dielectrical behavior, including Ohm's law, electrical resistivity, conductivity, and the behavior of semiconductors and dielectrics. It covers concepts such as current density, electron mobility, and types of semiconductors, along with their implications in electronic components like diodes and transistors. Additionally, it explains dielectric materials, their polarization mechanisms, and factors affecting dielectric strength and loss.

1. GROUP INFORMATION
GROUP: 7
TOPIC: ELECTRICAL PROPERTIES AND DIELECTRICAL BEHAVIOR
MEMBERS:
• Elevado, Edgar Jr. M. (1st
Presentor)
• Espinosa, Joemary C. (2nd
Presentor)
• Florendo, Justin (3rd
Presentor)
• Ganal, Ceejay (4th
Presentor)
• Jervoso, Frence Jarvy (5th
Presentor)

2. PROPERTIES AND
DIELECTRICAL
BEHAVIOR
MODULE 11

3. OHM’S LAW
Georg Simon Ohm – German physicist who
discovered the law, named after him, which
states that the current flow through a conductor is
directly proportional to the voltage and inversely
proportional to the resistance
V=IR
where:
V = Voltage (V)
I = Current (A)
R = Resistance (Ω)

4. OHM’S LAW

5. OHM’S LAW
Ohm’s Law Triangle

6. OHM’S LAW
Problem 1:
What is the voltage in a circuit if the current is 2mA and the
resistance is 1000 Ω?
Answer: 2V

7. OHM’S LAW
Problem 2:
What is the current in a circuit if the voltage is 2 V and the
resistance is 1000 Ω?
Answer: 2mA

8. OHM’S LAW
Problem 3:
What is the resistance in the circuit if the voltage is 2 V and the
current is 2mA?
Answer: 1000 Ω

9. ELECTRICAL RESISTIVITY
Electrical resistivity is a fundamental property of a material that
measures how strongly it resists electric current. Its unit is Ωm.
where:
R = Resistance
= Resistivity of the material
L = Length of Conductor
A = Cross Section Area

10. ELECTRICAL RESISTIVITY
Resistance formula
Unit for Resistivity
Resistivity formula

11. ELECTRICAL RESISTIVITY

12. ELECTRICAL CONDUCTIVITY
Electrical conductivity is the measure of the amount of electrical
current a material can carry or it's ability to carry a current. It is the
reciprocal of electrical resistivity. Its unit is .
where:
= Resistivity of the material
σ = electrical conductivity

13. ELECTRICAL CONDUCTIVITY

14. Current density is the product of electrical conductivity and electric field
intensity. Also, it is the ratio of current per unit area of cross section
perpendicular to flow in a region through which an electric current is flowing.
where:
J = Current Density
σ = Electrical Conductivity
E = Electric Field Intensity
CURRENT DENSITY
Where:
I = Current
A = Specimen Area
Note: E =
Where:
V = Voltage difference between two points
l = Distance separating the two points

15. CURRENT DENSITY

16. CLASSIFICATIONS OF SOLID
MATERIALS
1. CONDUCTORS
• Metals have conductivities on the order of
2. SEMICONDUCTORS
• Semiconductors have intermediate conductivities ranging between to
3. INSULATORS
• Insulators have low conductivities ranging between to
Note: Insulation can fail in a variety of ways, if voltage gets too high and
exceeds the "breakdown voltage" electrons will get excited to the point
where they break out of their stable orbit, current will then pass through the
material and often destroy the insulator.

17. ELECTRIC CURRENT
An electric current results from the motion of electrically
charged particles in response to forces that act on them from an
externally applied electric field.

18. ELECTRIC CURRENT
Within most solid materials a current arises from the flow of
electrons, which is termed electronic conduction.
For ionic materials, a net motion of charged ions is possible that
produces a current; such is termed ionic conduction.

19. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
Free electrons – (negatively charged) electrons that are in
random continuous motion and participate in the conduction
process. However, when connected to a battery, these free
electrons will flow opposite to the direction of the electric field
instead of random motion.
With Electric Field
No Electric Field

20. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
Hole – (positively charged) found in semiconductors and
insulators. Once an electron travels, a hole is created. A hole is
considered to have a charge that is of the same magnitude as
that for an electron, but of opposite sign (1.6x C).

21. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
Fermi Level– named after the Physicist, Enrico Fermi. Fermi
level is the highest energy level that an electron can occupy at
the absolute zero temperature 0K. It lies between the valence
band and conduction band because at absolute zero temperature
the electrons are all in the lowest energy state.

22. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
Fermi energy – is the value of the Fermi level at absolute zero
temperature 0K or (−273.15 degrees Celsius, or -459.67
Fahrenheit). It is also the maximum kinetic energy an electron
can attain at 0K. Fermi energy is constant for each solid.

23. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
Band gap– the distance between the valence band of electrons and
the conduction band. It represents the minimum energy that is
required to excite an electron up to a state in the conduction band
where it can participate in conduction. The size and existence of this
band gap allows one to visualize the difference between conductors,
semiconductors, and insulators.

24. CONDUCTION IN TERMS OF BAND AND ATOMIC
BONDING MODELS
There are four possible band configurations:
a. Partially Filled Bands (metals/conductors)
b. Overlapping Bands (metals/conductors)
c. Semiconductors
- narrow band gap (< 2 eV) note: eV = electron Volt
- more electrons excited across band gap
d. Insulators
- wide band gap (> 2 eV)
- few electrons excited across band gap

25. a b c d

27. ELECTRON MOBILITY
Electron Mobility – characterizes how quickly an electron can
move through a metal or semiconductor when pulled by an
electric field. In other words, it is simply the frequency of
scattering events. It is represented by .

28. ELECTRON MOBILITY
When a conductor is connected to a voltage source, an electric
field is applied. As a result, a force is brought to bear on the free
electrons; as a consequence, they all experience an
acceleration in a direction opposite to that of the field, by virtue
of their negative charge.

29. ELECTRON MOBILITY
Free electrons (negative charge) move in opposite direction
of that of the electric field when a conductor is connected to a
voltage source.

30. ELECTRON MOBILITY
The scattering of the free electrons will depend on the property of a material.
A semiconductor virtually behaves like an insulator at low temperatures.
However, at room temperature, some free electrons cross over to the conduction
band giving little conductivity to the semiconductor
In insulators, free electrons cannot freely move due to very low conductivity.
The scattering phenomenon is manifested as a resistance to the passage of an
electric current.
Several parameters are used to describe the extent of this scattering, these
include the drift velocity and the mobility of an electron.

31. ELECTRON MOBILITY
Drift velocity - The drift velocity represents the average electron
velocity in the direction of the force imposed by the applied field.

32. ELECTRON MOBILITY
Drift speed of electrons is less when compared with its speed in
random motion (no electric field).
With Electric Field No Electric Field

33. ELECTRON MOBILITY
Formula for Drift Velocity:
where:
= drift velocity ( )
= electron mobility ( )
= electric field ( )

34. ELECTRON MOBILITY

35. ELECTRON MOBILITY
Formula for conductivity (with electron mobility):
where:
= electrical conductivity
= number of free electrons
= absolute magnitude of electrical
charge
= electron mobility ( )

36. ELECTRON MOBILITY

37. ELECTRICAL RESISTIVITY OF METALS

38. ELECTRICAL RESISTIVITY OF METALS

39. ELECTRICAL RESISTIVITY OF METALS
MATTHIESSEN’S RULE — for a metal, total electrical resistivity (p)
equals the sum of thermal, impurity, and deformation contributions.
P = Pthermal + Pimpurity + Pdeformation

40. ELECTRICAL RESISTIVITY OF METALS

41. INFLUENCE OF TEMPERATURE
For the pure metal and all the copper–nickel alloys shown in Figure
12.8, the resistivity rises linearly with temperature above about 200C.

42. INFLUENCE OF TEMPERATURE
Formula for Thermal Resistivity:
Where:
= Thermal Resistivity
& = Constants for each metal
= Temperature
Note: Thermal resistivity is dependent on temperature
so they are directly proportional with each other.

43. INFLUENCE OF IMPURITIES
Impurities will distort the crystal lattice, hence impeding the
drift velocity. Therefore, the electrical resistivity increases as
impurities in a conductor increase.

44. INFLUENCE OF IMPURITIES
Formula for additions of a single
impurity that forms a solid
solution:
Where:
= Impurity Resistivity
= composition-independent
constant that is a function of both
the impurity and host metals.
= impurity concentration ci in terms of
the atom fraction (at%/100)
Formula for a two-phase alloy
consisting of α and β phases, a
rule-of-mixtures expression may
be utilized to approximate the
resistivity as follows:
Where:
V’s and ρ’s = represent volume
fractions and individual
resistivities for the respective
phases

45. INFLUENCE OF PLASTIC
DEFORMATION
Plastic deformation increases the electrical resistivity of a
material as a result of increased numbers of electron-
scattering dislocations.

46. INFLUENCE OF PLASTIC
DEFORMATION
The effect of deformation on resistivity is also represented in
Figure 12.8.

47. SEMI CONDUCTIVITY
Electrical conductivity of the semiconducting materials is not as
high as that of the metals.
The electrical properties of these materials are extremely sensitive
to the presence of even minute concentrations of impurities.

48. SEMI CONDUCTIVITY
Two types of semiconductors:
1. Intrinsic Semiconductors
• are those in which the electrical behavior is based on the
electronic structure inherent in the pure material.
2. Extrinsic Semiconductors
• Electrical characteristics are dictated by impurity atoms

49. INTRINSIC SEMICONDUCTORS

50. INTRINSIC SEMICONDUCTION IN TERMS OF ELECTRON AND HOLE
MIGRATION
Hole is an electric charge carrier with a positive charge , equal
in magnitude but opposite in polarity to the charge on the electron

51. INTRINSIC SEMICONDUCTION IN TERMS OF ELECTRON AND HOLE
MIGRATION

52. INTRINSIC SEMICONDUCTION IN TERMS OF ELECTRON AND HOLE
MIGRATION
e e e

53. NUMBER OF CHARGE CARRIERS

54. ESTIMATING CONDUCTIVITY

55. CHARGE CARRIERS IN INSULATORS AND
SEMICONDUCTORS

56. INTRINSIC SEMICONDUCTORS: CONDUCTIVITY VS.
TEMPERATURE

57. INTRINSIC VS. EXTRINSIC CONDUCTION

58. EXTRINSIC SEMICONDUCTORS: CONDUCTIVITY VS.
TEMPERATURE
DOPING
Doping - is the intentional introduction of impurities into an
intrinsic semiconductor for the purpose of modulating its electrical,
optical and structural properties

59. EXTRINSIC SEMICONDUCTORS: CONDUCTIVITY VS.
TEMPERATURE

60. SEMICONDUCTOR DEVICES
Semiconductor device (or Solid-state device) - is an electronic
component that relies on the electronic properties of a
semiconductor material (primarily silicon, germanium, and
gallium arsenide, as well as organic semiconductors) for its
function. It's Conductivity lies between conductors and
Insulators
Diodes Transistors

61. SEMICONDUCTOR DEVICES
Advantages of semiconductor devices:
• small size,
• low power consumption, and
• no warmup time

62. THE p-n RECTIFYING JUNCTION
Allows flow of electrons in one direction only (e.g., useful to
convert alternating current to direct current)
P stands for Positive, which means the semiconductor is rich in
holes or Positive charged ions
N stands for Negative and N-type semiconductors have Negative
charged ions or in other words have excess electrons

63. THE p-n RECTIFYING JUNCTION
Allows flow of electrons in one direction only (e.g., useful to
convert alternating current to direct current)
P stands for Positive, which means the semiconductor is rich in
holes or Positive charged ions
N stands for Negative and N-type semiconductors have Negative
charged ions or in other words have excess electrons

64. THE p-n RECTIFYING JUNCTION

65. PROPERTIES OF RECTIFYING JUNCTION

66. THE TRANSISTOR
Transistor – also called as “transfer-resistor”, is a small electronic
component with two main functions:
1. Switch circuits on and off
2. Amplify signals
Two major types of transistor:
1. Junction (or bimodal) transistor
2. Metal-oxide-semiconductor field-effect (MOSFET)

67. THE TRANSISTOR
Switch circuits on and off Amplify Signals

68. DIELECTRIC BEHAVIOR
Dielectric is another word for insulator. A dielectric material is
one that is electrically insulating (nonmetallic) and exhibits or
may be made to exhibit an electric dipole structure; that is, there
is a separation of positive and negative electrically charged
entities on a molecular or atomic level.
When a dielectric is placed between the plates of a capacitor, it
increases its capacitance

69. CAPACITANCE
Capacitance – is the ability of a component or circuit to collect
and store energy in the form of an electrical charge. Current
does not pass through capacitors. It's the electrons attraction
of the inverted flow, so there is not real electron flow inside the
capacitor.

70. CAPACITANCE
There are three formulas for finding the capacitance:
Where:
C = capacitance (Farads, F)
Q = charge (Coulumbs, C)
V = the voltage applied across the capacitor
A = represents the area of the plates
l = the distance between the plates
= the permittivity of a vacuum (8.85 x F/m)
ε = the permittivity of this dielectric medium (greater in magnitude than )

71. CAPACITANCE
Formula for relative permittivity (or dielectric constant):
Where:
= relative permittivity or dielectric constant
= the permittivity of a vacuum (8.85 x F/m)
ε = the permittivity of this dielectric medium (greater in magnitude than )

72. The dielectric constant is one material property that is of prime consideration
for capacitor design. The values of a number of dielectric materials are
contained in Table 11.2

73. FIELD VECTORS AND POLARIZATION
Dipole = di + pole
Di = two
Pole = rounded object
Electric Dipole – is pair of point charge with equal magnitude and
opposite in sign separated by a distance
Electric Dipole Moment (p) – is a measure of the separation of positive
and negative electrical charges within a system. A vector that is directed
from negative to positive.
Where:
q = magnitude of each dipole charge
d = distance of separation between them

74. FIELD VECTORS AND POLARIZATION
In the presence of an electric field, which is also a vector quantity, a force
(or torque) will come to bear on an electric dipole to orient it with the
applied field; The process of dipole alignment is termed polarization.
Electric
Field
No Electric
Field

75. FIELD VECTORS AND POLARIZATION
Again, returning to the capacitor, the surface charge density D (also
called dielectric displacement), or quantity of charge per unit area of
capacitor plate (C/), is proportional to the electric field E. When a vacuum
is present, then
the constant of proportionality being . Furthermore, an analogous
expression exists for the dielectric case; that is,

76. TYPES OF POLARIZATION
There are four types of polarization:
1. Electronic Polarization
2. Ionic Polarization
3. Orientation Polarization
4. Space Charge Polarization

77. TYPES OF POLARIZATION
1. Electronic Polarization
Electronic polarization may be
induced to one degree or
another in all atoms. It results
from a displacement of the
center of the negatively charged
electron cloud

78. TYPES OF POLARIZATION
2. Ionic Polarization
Ionic polarization occurs only in
materials that are ionic. An
applied field acts to displace
cations (+ charge) in one
direction and anions (- charge)
in the opposite direction, which
gives rise to a net dipole
moment.

79. TYPES OF POLARIZATION
3. Orientation Polarization
Orientation polarization results
from a rotation of the permanent
moments into the direction of
the applied field. It is found only
in substances that possess
permanent dipole moments.

80. TYPES OF POLARIZATION
3. Orientation Polarization
The total polarization P of a
substance is equal to the sum of
the electronic, ionic, and
orientation polarizations (Pe, Pi,
and Po, respectively), or

81. TYPES OF POLARIZATION
4. Space Charge Polarization
Also called ‘Interfacial’ or space
charge polarization occurs
when there is an accumulation
of charge at an interface
between two materials or
between two regions within a
material because of an external
field.

82. FREQUENCY DEPENDENCE OF THE DIELECTRIC
CONSTANT
Relaxation Frequency – The frequency at which the dielectric loss factor
reaches a maximum, for a dielectric material that has no static (d.c.)
conductivity and that is subjected to an alternating electromagnetic field.
Dielectric Loss – is the absorption of electrical energy by a dielectric
material that is subjected to an alternating electric field.
A low dielectric loss is desired at the frequency of utilization.

83. FREQUENCY DEPENDENCE OF THE DIELECTRIC
CONSTANT
Silicone rubber is usually a good choice for a buffer
layer due to its very low dielectric loss factor,
high dielectric constant, good mechanical
properties, high dielectric strength, and durability
after many welds.

84. DIELECTRIC STRENGTH
Dielectric Strength also known as “breakdown strength”,
represents the magnitude of an electric field necessary to produce
breakdown.

85. DIELECTRIC STRENGTH
Dielectric Breakdown – happens when very high electric fields are
applied across dielectric materials which may suddenly excite large
numbers of electrons to energies within the conduction band. As a
result, the current through the dielectric by the motion of these
electrons increases dramatically; sometimes localized melting,
burning, or vaporization produces irreversible degradation and
perhaps even failure of the material.

86. DIELECTRIC STRENGTH
If Voltage
exceeds 250V
Maximum Working
Voltage: 250V
Melted Capacitor
Burnt Capacitor

87. DIELECTRIC MATERIALS
A number of ceramics and polymers are used as insulators and/or
in capacitors. Many of the ceramics, including glass, porcelain,
steatite, and mica, have dielectric constants within the range of 6
to 10 (Table 11.2).

88. DIELECTRIC MATERIALS
These materials also exhibit a high degree of dimensional stability
and mechanical strength. Typical applications include power line
and electrical insulation, switch bases, and light receptacles.
Power line and
electrical insulation
Lightbulb socket
switch base
Light receptacles

89. DIELECTRIC MATERIALS
The titania (TiO2) and titanate ceramics, such as barium titanate
(BaTiO3), can be made to have extremely high dielectric constants,
which render them especially useful for some capacitor applications.

90. DIELECTRIC MATERIALS
The dielectric loss is increased by the following factors:
1. high frequency of the applied voltage
2. high value of the applied voltage
3. high temperature
4. humidity

91. OTHER ELECTRICAL CHARACTERISTICS OF
MATERIALS
1. Ferroelectricity
The group of dielectric materials called ferroelectrics exhibit
spontaneous polarization – that is, polarization in the absence of an
electric field.
Electric dipoles in a Ferroelectric
material with no electric field
Electric dipoles in a Ferroelectric
material with electric field

92. OTHER ELECTRICAL CHARACTERISTICS OF
MATERIALS
2. Piezoelectricity
Piezoelectricity is also called as “pressure electricity.” It’s
polarization is induced and an electric field is established across a
specimen by the application of external forces.
Examples of Piezoelectric Material
Piezoelectric materials include
titanates of barium and lead, lead
zirconate (PbZrO3), ammonium
dihydrogen phosphate (NH4H2PO4),
and quartz.
Buzzer
Piezo plate

93. End of presentation.
Thank you!