INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Sakarya Üniversitesi
Teknoloji Fakültesi
Elektrik Elektronik Mühendisliği Bölümü
T4 Blok
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Introducing the department
Introducing the EEE
Engineering ethic
Unit systems
Direct and alternative current
Resistor, capacitor, and coil
Voltage and current supplies
Ohm’s law, Kirchoff’s Laws
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Circuit concept, Serial, Parallel and Mixed
circuits
Semiconductor technology
General Occupational Health and Safety
Occupational Health and Safety in Electrical
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
MEASUREMENT
Measurement is the assignment of a number to a
characteristic of an object or event, which can be
compared with other objects or events.
Also measurement is a counting process. If you
want to measure your working desk, you should
choose a length unit. Suppose that you choose
your span and you measured 6 spans. In this
example, you measured the desk with your own
unit.
Different Measuring Instrument
Well, if everybody choose their own unit to
measure different quantities, how we are going to
agree, how we are going to trade, and how the
scientists are going to communicate?
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UNIT SYSTEMS
A unit of measurement is a definite magnitude of a physical quantity, defined and
adopted by convention or by law, that is used as a standard for measurement of the same
physical quantity. Any other value of the physical quantity can be expressed as a simple
multiple of the unit of measurement. Different systems of units used to be very
common. Today, there are five important unit systems:
MKS unit system: It is also known as metric system. The metric system is a decimal
systems of measurement based on its units for length, the metre, for time, the
second, and for mass, the kilogram.
FPS unit system: The foot–pound–second system or FPS system is a system of units built
on the three fundamental units foot for length, pound for either mass or force and
second for time.
CGS unit system: It is a system of measurement based on its units for length, the
centimetre, for time, the second, and for mass, the gram.
MKSA unit system: It is known as Giorgi system. In 1946 the International Committee for
Weights and Measures (CIPM) approved a proposal to use the ampere as that unit in a
four-dimensional system, the MKSA system.
SI unit system: The International System of Units (SI) defines seven fundamental
units: kilogram, metre, candela, second, ampere, kelvin, and mole.
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
UNIT SYSTEMS
A number of metric systems of units have evolved since the adoption of the original
metric system in France in 1791. Today, units of measurement are generally defined on a
scientific basis, overseen by governmental or independent agencies, and established in
international treaties, pre-eminent of which is the General Conference on Weights and
Measures (CGPM), established in 1875 by the Treaty of the metre and which oversees
the International System of Units (SI) and which has custody of the International
Prototype Kilogram.
The International System of Units (Système International d'Unités) is the modern revision
of the metric system. It is the world's most widely used system of units, both in everyday
commerce and in science. The SI was developed in 1960 from the metre-kilogramsecond (MKS) system, rather than thecentimetre-gram-second (CGS) system, which, in
turn, had many variants. During its development the SI also introduced several newly
named units that were previously not a part of the metric system.
Since the 1960s, the International System of Units (SI) is the internationally recognised
metric system. Metric units of mass, length, and electricity are widely used around the
world for both everyday and scientific purposes.
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
UNIT SYSTEMS
Base quantity
Base quantity
Base unit
Symbol
time
second
s
angle
length
metre
m
Solid angle
mass
kilogram
kg
electric current
Ampere
A
temperature
Kelvin
K
amount of
substance
mole
mol
luminous
intensity
candela
cd
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Base unit
Symbol
radian
rad
steradian
sr
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UNIT SYSTEMS
Meter is defined as the distance travelled by light in a specific fraction – about one threehundred millionths – of a second (17. CGPM, 1983).
Kilogram, manufactured in 1799 and from which the IPK (International Prototype of the
Kilogram) is derived, had a mass equal to the mass of 1.000025 liters of water at 4 °C (3.
CGPM, 1901).
Second: It is quantitatively defined in terms of a certain number of periods – about 9
billion – of a certain frequency of radiation from the caesium-133 atom: a so-called
atomic clock (13. CGPM, 1967).
Ampere: It is the constant current that will produce an attractive force of
2 × 10−7 newtons per metre of length between two straight, parallel conductors of infinite
length and negligible circular cross section placed one meter apart in a vacuum (9.CGPM,
1948).
Kelvin: It is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the
triple point of water (exactly 0.01 °C or 32.018 °F) (13. CGPM, 1967).
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UNIT SYSTEMS
Mole: It is defined as the amount of any chemical substance that contains as many
elementary entities, e.g., atoms, molecules, ions, or electrons, as there are atoms in 12
grams of pure carbon-12 (14. CGPM, 1971).
Candela: It is the luminous intensity, in a given direction, of a source that emits
monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in
that direction of 1⁄683 watt per steradian (16. CGPM, 1979).
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UNIT SYSTEMS
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UNIT SYSTEMS
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UNIT SYSTEMS
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INTRODUCTION TO ELECTRICITY
ATOMS
The smallest particle of a material.
Consist of electrons and nucleus.
Nucleus has a positive charge.
Electrons have negative charge and turn
around the nucleus in the certain orbits.
The number of electrons in an orbit is
calculated by 2.n2.
Unless there is an external effect, the
number of protons is equal to the number of
electrons.
The outer orbit is called ‘valence orbit’.
The electrons in this orbit is also called
‘valence electron’ or‘free electron.
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INTRODUCTION TO ELECTRICITY
Coulomb’s Law: If the two charges have the same sign, the electrostatic force
between them is repulsive; if they have different signs, the force between them is
attractive.
Coulomb's law can also be stated as a simple mathematical expression.
where ke is Coulomb’s constant (ke =8.9875517873681764 x 109 N∙m2∙C-2), and q1
and q2 are the signed magnitudes of the charges, the scalar r is the distance between
the charges.
the charge of 1 e- : 1,6 ∙ 10-19 Coulombs
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INTRODUCTION TO ELECTRICITY
CONDUCTORS:
They conduct electricity.
The number of valence
Cupper Atoms
Valence
electron
electrons are less than 4.
The conductivity depends on
the number of valence
electrons. If it is one, good
conductivity!
Copper, gold, silver,
aluminum, iron…
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INTRODUCTION TO ELECTRICITY
INSULATORS
They don’t conduct electricity basically.
The number of valence electrons is higher than 4. (5-8)
The number of electrons in the valence orbit can’t be more than 8.
If the number of electrons in this orbit is less, insulation level is
also low.
If high voltage and frequency signal is applied to an insulator, it
may conduct electricity a little.
Plastic, rubber, glass, ceramic, air…
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INTRODUCTION TO ELECTRICITY
 SEMICONDUCTOR:
 It conducts electricity under certain conditions.
 The number of valence electrons is 4.
 Silicon, Germanium (they are insulators in their
a) Silicon Atoms
pure state)
 Can be inductor with doping elements
(Arsenic, Galium, İndium etc.).
 Used to produce some electronic devices such
as diode, transistor, integrated circuits, etc.
b) Germanium Atoms
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INTRODUCTION TO ELECTRICITY
bandgap (forbidden)
conductivity band
bandgap
(forbidden)
energy level
conductivity band
energy level
energy level
 Energy bands in conductor, semiconductor, and
insulator atoms:
conductivity band
bandgap
(forbidden)
valence band
valence band
valence band
a) Conductor
b) Semiconductor
c) Insulator
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resistance
Electricity can be liken to
running water from a tap plugged
to a container filled with water, as
illustrated in figure.
The height of the water
 Voltage
The quantity of running water
 Current
The tap
 Resistance
Volt
Current, Voltage, Resistance
current
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
Moving electrons in a
conductor is called
‘CURRENT’.
Electron flow occurs from
negative to positive.
Copper wire
 Hole flow occurs from
positive to negative.
Copper
atoms
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Electron flow
Electron
nucleus
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
Unit: Ampere (A)
1A current: It represents 1 coulomb charge
movement in a second.
1A= 1C/S (Coulomb/Second)
1 C = 6,250,000,000,000,000,000 electron
1,610-19C = 1electron
Q
I
t
I=current (Ampere)
Q: charge quantity (coulomb)
 t: time (second)
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I,i
Akım kaynağı
Current
Source
+
I,i
-
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
The energy forced the electrons to flow
is called ‘VOLTAGE’.
It is a measure of potential difference
between two points.
Unit: Volt (V)
Example: The voltages in a circuit have
been measured as
VA=5 V (at the point A), and
VB=2 V (at the point B).
So, what is the potential difference
from A to B point (VAB)?
What is the potential difference from B
to A point (VBA)?
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A
V
+
-
E, U
V1
B
+
+
-
-
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
 The opposition to the flow of
electric current is called
‘RESISTANCE’.
 It consists of friction between
atoms and other particles in the
conductor, and electrons, moving in
the conductor.
 Unit: Ohm ()
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R
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Current, Voltage, Resistance
 On which physical conditions the resistance of a conductor
depends?
 It is inversely proportional to the cross section,
 It is proportional to the length,
 It is proportional to the temperature,
 It depends on the type of conductor. Resistivity of all
conductors are different.
For example, the resistances of Cupper and Aluminum wires in the
same length and same cross section are different.
Resistivity: It is the resistance of a conductor 1 meter in
length and 1 mm2 in cross sectional area. (20 ̊C)
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Current, Voltage, Resistance
Bir iletkenin direnci:
Length (meter)
L
R 
S
Resistivity (ohm)
Cross-section (mm2)
Resistivities of some metals
CONDUCTOR
Silver
Cupper
Gold
Aluminum
Iron
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RESISTIVITY (ρ)
0,016
0,017
0,023
0,028
0,012
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
R1 T  t1

R2 T  t 2
Resistance
 R1 : value of a resistor at
t1 temperature
CONDUCTOR
T COEFFICIENT ( ̊C)
Lead
Silver
Cupper
Aluminum
Zinc
Brass
218
243
235
236
250
650
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 R2 : value of same
resistor at t2 temperature
All metals have a ‘T coefficient’.
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INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING
Current, Voltage, Resistance
Example: The resistance of a Cupper wire at 20 ̊ C is 5 . Find
the resistance at 60 ̊ C.
for Cupper, T=235
20
60
5
5,78 
Example: The resistance of a Lead wire at 20 ̊ C is 5 . Find
the resistance at 60 ̊ C.
for Lead, T=218
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20
60
5
5,84 
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