Lecture Slides for the course Fundamentals of Electrical Engineering delivered by me to First Semester Diploma in Mechanical Engineering.

1. PEE-102A
Fundamentals of Electrical Engineering
Lecture-1
Instructor:
Mohd. Umar Rehman
EES, University Polytechnic, AMU
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2. Unit-I: Electricity and Magnetism
Voltage, Current, Resistance—series & parallel connections, Temperature coef-
ficient of resistance, Ohm’s law, Electrical power and energy. Kirchhoff’s laws,
Illustrative numerical problems. Magnetism and its effects, Laws of Magnetic
force, Magnetic lines of force, Magnetic flux, Magnetic Flux Density, Magnetic
Field strength, Permeability, Force on a current carrying conductor lying in a
magnetic field, Fleming’s Left Hand Rule, Magnetic hysteresis and eddy cur-
rents.
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3. Why Electrical Engineering?
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4. Why Electrical Engineering?
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5. Why Electrical Engineering?
Basic Necessity, impossible to imagine our lives without electricity.
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6. Why Electrical Engineering?
Basic Necessity, impossible to imagine our lives without electricity.
Electrical Engineering is the study of generation, transmission, distribution
and efficient utilization of electrical energy.
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7. Why Electrical Engineering?
Basic Necessity, impossible to imagine our lives without electricity.
Electrical Engineering is the study of generation, transmission, distribution
and efficient utilization of electrical energy.
Wide range of applications.
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8. Why Electrical Engineering?
Basic Necessity, impossible to imagine our lives without electricity.
Electrical Engineering is the study of generation, transmission, distribution
and efficient utilization of electrical energy.
Wide range of applications.
As a mechanical engineer, you’ll be using various machinery and equip-
ments that operate on principles of electrical engineering.
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9. Electrical nature of matter (Electric Charge)
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10. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
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11. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
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12. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
Normally, number of protons = number of electrons, and the matter is said
to be electrically neutral.
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13. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
Normally, number of protons = number of electrons, and the matter is said
to be electrically neutral.
Charge is also a basic property of matter like mass.
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14. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
Normally, number of protons = number of electrons, and the matter is said
to be electrically neutral.
Charge is also a basic property of matter like mass.
no. of protons > no. of electrons → positive charge.
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15. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
Normally, number of protons = number of electrons, and the matter is said
to be electrically neutral.
Charge is also a basic property of matter like mass.
no. of protons > no. of electrons → positive charge.
no. of protons < no. of electrons → negative charge.
PEE-102A U-I, L-1 5 / 18

16. Electrical nature of matter (Electric Charge)
All matter consists of atoms.
All atoms consists of protons (+ve charge), neutrons (0 charge) & electrons
(−ve charge).
Normally, number of protons = number of electrons, and the matter is said
to be electrically neutral.
Charge is also a basic property of matter like mass.
no. of protons > no. of electrons → positive charge.
no. of protons < no. of electrons → negative charge.
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17. Electric Charge...Contd
SI Unit is Coulomb (C)
Charge on an e− = −1.602×10−19 C.
1 C = 6.25×1018 e−s
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18. Potential/Voltage
Potential is the work done in imparting energy to a charge while moving it
from one point to another.
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19. Potential/Voltage
Potential is the work done in imparting energy to a charge while moving it
from one point to another.
V =
W
Q
Joules/Coulomb = Volts.
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20. Potential/Voltage
Potential is the work done in imparting energy to a charge while moving it
from one point to another.
V =
W
Q
Joules/Coulomb = Volts.
Potential difference is the difference between potential values at two points.
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21. Potential/Voltage
Potential is the work done in imparting energy to a charge while moving it
from one point to another.
V =
W
Q
Joules/Coulomb = Volts.
Potential difference is the difference between potential values at two points.
VAB = VA −VB
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22. Current
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23. Current
Current → Flow
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24. Current
Current → Flow
Electric Current → Flow of electric charge along a definite path/direction
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25. Current
Current → Flow
Electric Current → Flow of electric charge along a definite path/direction
Direction is along the ’movement’ of the protons or opposite to the move-
ment of the electrons.
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26. Current
Current → Flow
Electric Current → Flow of electric charge along a definite path/direction
Direction is along the ’movement’ of the protons or opposite to the move-
ment of the electrons.
In a circuit, current flows from +ve terminal to the -ve terminal of a battery.
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27. Current
Current → Flow
Electric Current → Flow of electric charge along a definite path/direction
Direction is along the ’movement’ of the protons or opposite to the move-
ment of the electrons.
In a circuit, current flows from +ve terminal to the -ve terminal of a battery.
I =
Q
t
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28. Current
Current → Flow
Electric Current → Flow of electric charge along a definite path/direction
Direction is along the ’movement’ of the protons or opposite to the move-
ment of the electrons.
In a circuit, current flows from +ve terminal to the -ve terminal of a battery.
I =
Q
t
SI Unit: Amperes = Coulombs/sec.
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29. Resistance
Property of matter which offers opposition to the flow of electric current is
called resistance
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30. Resistance
Property of matter which offers opposition to the flow of electric current is
called resistance
The moving electrons collide with atoms or molecules of the substance ;
each collision resulting in the liberation of heat.
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31. Resistance...Contd
Resistance of a material depends upon its:
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32. Resistance...Contd
Resistance of a material depends upon its:
(i) Length, R ∝ l
(ii) Area of cross-section, R ∝
1
a
(iii) Nature of material
(iv) Temperature
(v) Combining, first two factors we get,
R ∝
l
a
R = ρ
l
a
Where, ρ is known as specific resistance or resistivity, its unit is Ω−m
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33. Temperature Dependence of Resistance
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34. Temperature Dependence of Resistance
Resistance of most electrical materials change with the change in temper-
ature.
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35. Temperature Dependence of Resistance
Resistance of most electrical materials change with the change in temper-
ature.
The resistance of a pure metallic conductor increases with an increase in
temperature and decreases with a decrease in temperature.
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36. Temperature Dependence of Resistance
Resistance of most electrical materials change with the change in temper-
ature.
The resistance of a pure metallic conductor increases with an increase in
temperature and decreases with a decrease in temperature.
The variation of resistance with temperature is measured in terms of tem-
perature coefficient of resistance.
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37. Temperature Dependence of Resistance
Resistance of most electrical materials change with the change in temper-
ature.
The resistance of a pure metallic conductor increases with an increase in
temperature and decreases with a decrease in temperature.
The variation of resistance with temperature is measured in terms of tem-
perature coefficient of resistance.
It is defined as the change in resistance per Kelvin (or ◦C), expressed as a
fraction of the resistance at the base temperature considered. Its symbol
is α
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38. Temperature Dependence...Contd
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39. Temperature Dependence...Contd
Let,
R1 = resistance at temperature Θ1
◦
C
α1 = temperature coefficient of resistance at Θ1
◦
C
R2 = resistance at temperature Θ2
◦
C
α2 = temperature coefficient of resistance at Θ2
◦
C
By definition,
α =
change in resistance
change in temperature
resistance at the base temperature considered
Hence,
α1 =
R2 −R1
Θ2 −Θ1
R1
α2 =
R2 −R1
Θ2 −Θ1
R2
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40. Temperature Dependence...Contd
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41. Temperature Dependence...Contd
Combining above equations, we get
R2 = R1 [1+α1 (Θ2 −Θ1)]
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42. Temperature Dependence...Contd
Combining above equations, we get
R2 = R1 [1+α1 (Θ2 −Θ1)]
The base temperature is usually taken as 0 ◦C.
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43. Series and Parallel Combination of Resistance: Review
Resistors in series:
Rs = R1 +R2 +R3 +···
Resistors in parallel:
1
Rp
=
1
R1
+
1
R2
+
1
R3
+···
For two resistors in parallel, direct formula
Rp =
R1R2
R1 +R2
=
Product
Sum
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44. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
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45. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
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46. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
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47. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
I = kV
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48. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
I = kV
I =
V
R
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49. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
I = kV
I =
V
R
V = IR
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50. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
I = kV
I =
V
R
V = IR
PEE-102A U-I, L-1 15 / 18

51. Ohm’s Law
Ohm’s Law combines Voltage, Current and Resistance.
It states that "current through a conductor is proportional to the applied
voltage, provided the physical conditions remain the same"
Mathematically,
I ∝ V
I = kV
I =
V
R
V = IR
Graphically, the Voltage v/s Current graph is a straight line.
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52. Electrical Power
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53. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
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54. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
When voltage is applied to a circuit, it causes current (i.e. electrons) to
flow through it.
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55. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
When voltage is applied to a circuit, it causes current (i.e. electrons) to
flow through it.
Clearly, work is being done in moving the electrons in the circuit. This work
done in moving the electrons in a unit time is called the electric power.
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56. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
When voltage is applied to a circuit, it causes current (i.e. electrons) to
flow through it.
Clearly, work is being done in moving the electrons in the circuit. This work
done in moving the electrons in a unit time is called the electric power.
Formula:
P = VI = I2
R =
V2
R
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57. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
When voltage is applied to a circuit, it causes current (i.e. electrons) to
flow through it.
Clearly, work is being done in moving the electrons in the circuit. This work
done in moving the electrons in a unit time is called the electric power.
Formula:
P = VI = I2
R =
V2
R
Unit: Watts (W), Horsepower (1 hp = 746 W)
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58. Electrical Power
The rate at which work is done in an electric circuit is called its electric
power i.e.
Electric Power =
Work done in electric circuit
Time
When voltage is applied to a circuit, it causes current (i.e. electrons) to
flow through it.
Clearly, work is being done in moving the electrons in the circuit. This work
done in moving the electrons in a unit time is called the electric power.
Formula:
P = VI = I2
R =
V2
R
Unit: Watts (W), Horsepower (1 hp = 746 W)
Larger units: kilowatt (1 kW = 103 W), megawatt (1 MW = 106 W)
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59. Electrical Energy
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60. Electrical Energy
The total work done in an electric circuit is called electrical energy i.e
Electrical Energy = Electric Power ×time
= VIt = I2
Rt =
V2
R
t
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61. Electrical Energy
The total work done in an electric circuit is called electrical energy i.e
Electrical Energy = Electric Power ×time
= VIt = I2
Rt =
V2
R
t
It may be noted that the formulae for electrical energy can be readily de-
rived by multiplying the electric power by ‘t’, the time for which the current
flows.
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62. Electrical Energy
The total work done in an electric circuit is called electrical energy i.e
Electrical Energy = Electric Power ×time
= VIt = I2
Rt =
V2
R
t
It may be noted that the formulae for electrical energy can be readily de-
rived by multiplying the electric power by ‘t’, the time for which the current
flows.
The unit of electrical energy will depend upon the units of electric power
and time, however, SI unit is Joules (J) and commercial unit is kilowatt-hour
(kWh). (1 kWh = 3.6×106 J)
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63. Circuit Terminology
Please see the following link before Lecture-2:
Khan Academy
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