INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING Sakarya Üniversitesi Teknoloji Fakültesi...

INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING

Sakarya ÜniversitesiTeknoloji FakültesiElektrik Elektronik Mühendisliği Bölümü T4 Blok

• 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

• Circuit concept, Serial, Parallel and Mixed circuits

• Semiconductor technology• General Occupational Health and Safety • Occupational Health and Safety in Electrical

1Electrical and Electronics Engineering


MEASUREMENT

2

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.

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?

Electrical and Electronics Engineering

Different Measuring Instrument


UNIT SYSTEMS

3

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.


https://en.wikipedia.org/wiki/Kilogram

https://en.wikipedia.org/wiki/Metre

https://en.wikipedia.org/wiki/Candela

https://en.wikipedia.org/wiki/Second

https://en.wikipedia.org/wiki/Ampere

https://en.wikipedia.org/wiki/Kelvin

https://en.wikipedia.org/wiki/Mole_(unit)


UNIT SYSTEMS

4

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-kilogram-second (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.



UNIT SYSTEMS


Base quantity Base unit Symbol

time second s

length metre m

mass kilogram kg

electric current Ampere A

temperature Kelvin K

amount of substance mole mol

luminous intensity candela cd

Base quantity Base unit Symbol

angle radian rad

Solid angle steradian sr

https://en.wikipedia.org/wiki/Time


https://en.wikipedia.org/wiki/Length


https://en.wikipedia.org/wiki/Mass

https://en.wikipedia.org/wiki/Kilogram

https://en.wikipedia.org/wiki/Electric_current



https://en.wikipedia.org/wiki/Ampere

https://en.wikipedia.org/wiki/Temperature

https://en.wikipedia.org/wiki/Kelvin




https://en.wikipedia.org/wiki/Mole_(unit)

https://en.wikipedia.org/wiki/Luminous_intensity



https://en.wikipedia.org/wiki/Candela

https://en.wikipedia.org/wiki/Time






UNIT SYSTEMS

6

Meter is defined as the distance travelled by light in a specific fraction – about one three-hundred 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).



UNIT SYSTEMS

7

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).



UNIT SYSTEMS



INTRODUCTION TO ELECTRICITY


ATOMSThe 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.




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

https://en.wikipedia.org/wiki/File:Coulombslaw.svg




CONDUCTORS: They conduct electricity.

The number of valence

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…

Cupper Atoms

Valence electron




INSULATORSThey 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…




SEMICONDUCTOR: It conducts electricity under certain conditions.

The number of valence electrons is 4.

Silicon, Germanium (they are insulators in their

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.

a) Silicon Atoms

b) Germanium Atoms




Energy bands in conductor, semiconductor, and insulator atoms:

a) Conductor c) Insulatorb) Semiconductor

valence band valence bandvalence band

bandgap (forbidden) bandgap (forbidden)

bandgap (forbidden)

conductivity band conductivity band

conductivity band

ene

rgy

leve

l

ene

rgy

leve

l

ene

rgy

leve

l


Current, Voltage, 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

VoltageThe quantity of running water

CurrentThe tap

ResistanceVo

lt

resis

tanc

e

current




Moving electrons in a conductor is called

‘CURRENT’.Electron flow occurs from

negative to positive. Hole flow occurs from

positive to negative.

Copper wire

Electron flowElectron

nucleus

Copperatoms




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 electron1,610-19C = 1electron

I=current (Ampere)Q: charge quantity (coulomb)

t: time (second)

I,i

I,i+

-

Akım kaynağıCurrent Source

tQI




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)?

VA B

+

-

+

-V1

E, U +-




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 ()

R




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) ̊




SLR

Bir iletkenin direnci:

Cross-section (mm2)

Resistivity (ohm)

Length (meter)

Resistivities of some metalsCONDUCTOR RESISTIVITY (ρ)

Silver 0,016Cupper 0,017

Gold 0,023Aluminum 0,028

Iron 0,012




2

1

2

1tTtT

RR

R1 : value of a resistor at t1 temperature

R2 : value of same resistor at t2 temperature

All metals have a ‘T coefficient’.

CONDUCTOR T COEFFICIENT ( ̊C)Lead 218Silver 243

Cupper 235Aluminum 236

Zinc 250Brass 650

Resistance




Example: The resistance of a Cupper wire at 20 ̊ C is 5 . Find the resistance at 60 ̊ C.

for Cupper, T=235 20 5 60 5,78

Example: The resistance of a Lead wire at 20 ̊ C is 5 . Find the resistance at 60 ̊ C.

for Lead, T=21820 5 60 5,84

INTRODUCTION TO ELECTRICAL AND ELECTRONICS ENGINEERING Sakarya Üniversitesi Teknoloji Fakültesi...

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