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Файл:Basics of electronics. Study aid
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TOMSK POLYTECHNIC UNIVERSITY
O.A. Kozhemyak, D.N. Ogorodnikov
BASICS OF ELECTRONICS
Recommended for publishing as a study aid
by the Editorial Board of Tomsk Polytechnic University
Tomsk Polytechnic University Publishing House
2020
UDC 621.38(075.8)
BBC 32.85я73
K58
Kozhemyak O.A.
K58 Basics of electronics : study aid / O.A. Kozhemyak,
D.N. Ogorodnikov ; Tomsk Polytechnic University. – Tomsk : TPU
Publishing House, 2020. – 142 p.
ISBN 978-5-4387-0932-9
This textbook focuses on components of electrical and electronic circuits,
semiconductor devices and their main applications; analog integrated circuits, their
general features, principles of operation.
The manual is intended for students majoring in the specialties 11.03.04
“Electronics and Nanoelectronics” and 12.03.04 “Biotechnical Systems and
Technologies”.
UDC 621.38(075.8)
BBC 32.85я73
Reviewers
Candidate of Sciences, Head of the Laboratory,
Tomsk State University of Control Systems and Radioelectronics
A.V. Osipov
Candidate of Sciences, Associate Professor,
Tomsk State University
M.L. Gromov
ISBN 978-5-4387-0932-9 © FSAEI HE NR TPU, 2020
© Kozhemyak O.A., Ogorodnikov D.N., 2020
© Design. Tomsk Polytechnic University
Publishing House, 2020
CONTENTS
CHAPTER 1. D.C. CIRCUITS ......................................................................................... 5
1.1. Introduction ............................................................................................................... 5
1.2. Electric Current, Electromotive Force, Potential Difference,
Energy and Power, Resistance and Conductance ...................................................... 5
1.2.1. Resistance and Conductance .............................................................................. 7
1.2.2. Internal Resistance and Output Voltage of an E.M.F. Source ......................... 10
1.3. Resistors in Series and in Parallel ........................................................................... 11
1.3.1. Resistors in Series ............................................................................................ 11
1.3.2. Resistors in Parallel .......................................................................................... 12
1.3.3. The Voltage Divider ......................................................................................... 13
1.3.4. The Current Divider ......................................................................................... 13
1.3.5. The Variable Potential Divider ......................................................................... 14
1.4. Kirchhoff’s Laws ..................................................................................................... 15
1.4.1. Kirchhoff’s Current Law .................................................................................. 15
1.4.2. Kirchhoff’s Voltage Law .................................................................................. 16
Self-Assessment Questions ............................................................................................ 16
CHAPTER 2. SIGNALS, WAVEFORMS AND A.C. COMPONENTS ..................... 18
2.1. Electrical Waveforms .............................................................................................. 18
2.2. Sinusoidal Waveforms and Frequency .................................................................... 20
2.3. Voltage, R.M.S. and Power ..................................................................................... 24
2.3.1. Periodic Waveforms ......................................................................................... 24
2.3.2. Non-periodic Waveforms: Signals and Noise .................................................. 28
2.3.3. Symbols for Voltages and Currents .................................................................. 30
2.4. A.C. Components .................................................................................................... 32
2.4.1. Capacitors ......................................................................................................... 32
2.4.2. Inductors ........................................................................................................... 36
2.4.3. Transformers .................................................................................................... 39
Self-Assessment Questions ............................................................................................ 43
CHAPTER 3. SIMPLE A.C. CIRCUITS ....................................................................... 44
3.1. Low-Pass Networks ................................................................................................. 44
3.2. High-Pass Networks ................................................................................................ 46
Self-Assessment Questions ............................................................................................ 47
CHAPTER 4. DIODES .................................................................................................... 48
4.1. Semiconductors. P-N Junction. ............................................................................... 48
4.2. Forward and Reverse Bias. V-I characteristics ....................................................... 50
4.3. P-N Diode Applications .......................................................................................... 52
4.4. Special Diodes ......................................................................................................... 55
4.4.1. Zener Diode ...................................................................................................... 57
4.4.2. Schottky Diode ................................................................................................. 60
4.4.3. Photodiode ........................................................................................................ 62
4.4.4. Light-Emitting Diode ....................................................................................... 64
Self-Assessment Questions ............................................................................................ 68
CHAPTER 5. BIPOLAR JUNCTION TRANSISTORS .............................................. 69
5.1. Construction. Characteristics ................................................................................... 69
5.2. Model of Transistor ................................................................................................. 72
3
5.3. Types of Configuration. Modes of Operation ......................................................... 73
Self-Assessment Questions ............................................................................................ 75
CHAPTER 6. FIELD EFFECT TRANSISTORS ......................................................... 76
6.1. Construction. Characteristics ................................................................................... 76
6.2. Applications ............................................................................................................. 77
Self-Assessment Questions ............................................................................................ 78
CHAPTER 7. THYRISTORS ......................................................................................... 79
7.1. Silicon Controlled Rectifier ..................................................................................... 79
7.2. Types of Thyristor ................................................................................................... 83
Self-Assessment Questions ............................................................................................ 85
CHAPTER 8. AMPLIFIERS .......................................................................................... 86
8.1. Classification of Amplifiers .................................................................................... 86
8.2. Common-Emitter Amplifier .................................................................................... 87
Self-Assessment Questions ............................................................................................ 88
CHAPTER 9. ANALOGUE INTEGRATED CIRCUITS ............................................ 89
9.1. Operational Amplifiers ............................................................................................ 89
9.1.1. General Properties of Op-Amps ....................................................................... 92
9.1.2. Operational Amplifier Types .......................................................................... 100
9.2. Basic Op-Amp Circuit Applications ..................................................................... 102
9.2.1. The Inverting Amplifier ................................................................................. 103
9.2.2. The Noninverting Amplifier ........................................................................... 106
9.2.3. The Summing Amplifier Circuits ................................................................... 110
9.2.4. The Differential Amplifier ............................................................................. 112
9.2.5. The Integrator ................................................................................................. 112
9.2.6. The Differentiator ........................................................................................... 114
9.2.7. Active Filters .................................................................................................. 116
9.3. Signal Generators .................................................................................................. 118
9.3.1. Sinusoidal Oscillator ...................................................................................... 118
9.3.2. Rectangular Waveform Generators ................................................................ 120
9.3.3. The 555 Timer ................................................................................................ 125
Self-Assessment Questions .......................................................................................... 136
SUMMARY ..................................................................................................................... 138
BIBLIOGRAPHY .......................................................................................................... 139
APPENDIX A ................................................................................................................. 140
Acknowledgements
We would like to thank our colleagues who have assisted us in the
preparation of this Textbook. We would like to give special thanks to
Tatyana Yevtushenko for her help and support.
4
CHAPTER 1. D.C. CIRCUITS
1.1. Introduction
This chapter focuses on the basic facts that you should know. It is about
voltage, current, power, resistance and conductance in d.c. circuits.
1.2. Electric Current, Electromotive Force, Potential Difference,
Energy and Power, Resistance and Conductance
An electric current is the rate of flow of electric charge past a point or
region. In electric circuits this charge is often carried by electrons moving
through a wire. It can also be carried by ions in an electrolyte, or by both ions
and electrons such as in an ionized gas (plasma).
At normal temperatures current will flow through a conductor if a battery
is connected across it. Substances that let electric charge easily flow through
them are called conductors. One of the best-known conductors is copper.
Electrons, being negative, will be attracted towards the positive side of the
battery while holes (i. e. positive charge carriers) will move in opposite
direction. However, current direction is defined, by convention, as the direction
of movement of positive charge and therefore both holes and electrons
contribute to current flowing through the conductor in the hole direction.
Direct current (DC) is the unidirectional flow of an electric charge.
The SI unit of electric current is the ampere, which is the flow of electric
charge across a surface at the rate of one coulomb per second. The ampere
(symbol: A) is an SI base unit. Electric current is measured using a device
called an ammeter.
A battery is a prime example of d.c. power. Direct current may flow
through a conductor such as a wire, but can also flow through
semiconductors, insulators, or even through a vacuum as in electron or ion
beams. The electric current flows in a constant direction, distinguishing it
from alternating current (AC).
Electromotive force, abbreviated e.m.f. (denoted by ε and measured in
volts), is the electrical action produced by a non-electrical source. A device
that converts other forms of energy into electrical energy (a ‘transducer’),
such as a battery (converting chemical energy) or generator (converting
mechanical energy), provides an e.m.f. as its output. Sometimes an analogy
to water ‘pressure’ is used to describe electromotive force. (The word ‘force’
in this case is not used to mean force of interaction between bodies, as may
be measured in pounds or newtons.)
5
In electromagnetic induction, e.m.f. can be defined around a closed loop
P
of conductor as the electromagnetic work that would be done on an electric
charge (an electron in this instance) if it travels once around the loop. For a
time-varying magnetic flux linking a loop, the electric potential scalar field is
not defined due to a circulating electric vector field, but an e.m.f. nevertheless
does work that can be measured as a virtual electric potential around the loop.
In the case of a two-terminal device (such as an electrochemical cell),
the equivalent e.m.f. can be measured as the open-circuit potential
difference or ‘voltage’ between the two terminals. This potential difference
can drive an electric current if an external circuit is attached to the terminals.
Devices that can provide e.m.f. include electrochemical cells,
thermoelectric devices, solar cells, photodiodes, electrical generators,
transformers. The shifting of the Earth's magnetic field during a geomagnetic
storm induces currents in the electrical grid as the lines of the magnetic field
are shifted about and cut across the conductors.
Electrical energy is the energy which is caused by the movement of the
electrons from one place to another.
In other words, electrical energy is the
work done by the moving streams of the electrons or charges.
The basic unit of the electrical energy is the joule (or watt-second). The
energy expended in an electrical circuit is said to be one joule (or watt
second) if one-ampere current flows through the circuit for one second when
the potential difference of one volt is applied across it. The commercial or
practical unit of energy is the kilowatt-hour (kWh).
Electric power is the rate, per unit time, at which electrical energy is
transferred by an electric circuit. The SI unit of power is the watt, one joule
per second.
Electric power is usually produced by electric generators, but can also
be supplied by sources such as electric batteries. It is usually supplied to
businesses and homes (as domestic mains electricity) by the electric power
industry through an electric power grid.
Electric power, like mechanical power, is the rate of doing work,
measured in watts, and represented by the letter P. The electric power in watts
produced by an electric current I consisting of a charge of Q coulombs every t
seconds passing through an electric potential (voltage) difference of V is
work done per unit time VI
where Q is electric charge in coulombs
t is time in seconds
I is electric current in amperes
V is electric potential or voltage in volts
6
VQ
t
,
Electric power is transformed to other forms of energy when electric
I
charges move through an electric potential (voltage) difference, which occurs
in electrical components in electric circuits. From the standpoint of electric
power, components in an electric circuit can be divided into two categories:
Passive devices or loads: When electric charges move through a
potential difference from a higher to a lower voltage, that is when
conventional current (positive charge) moves from the positive (+) terminal
to the negative () terminal, work is done by the charges on the device. The
potential energy of the charges due to the voltage between the terminals is
converted to kinetic energy in the device. These devices are called passive
components or loads; they ‘consume’ electric power from the circuit,
converting it to other forms of energy such as mechanical work, heat, light,
etc. Examples are electrical appliances, such as light bulbs, electric motors,
and electric heaters.
Active devices or power sources: If the charges are moved by an
‘exterior force’ through the device in the direction from the lower electric
potential to the higher, (so positive charge moves from the negative to the
positive terminal), work will be done on the charges, and energy is being
converted to electric potential energy from some other type of energy, such
as mechanical energy or chemical energy. Devices in which this occurs are
called active devices or power sources; such as electric generators and
batteries.
Some devices can be either a source or a load, depending on the voltage
and current through them. For example, a rechargeable battery acts as a
source when it provides power to a circuit, but as a load when it is connected
to a battery charger and is being recharged.
1.2.1. Resistance and Conductance
The magnitude of the current flowing in a circuit depends on the
magnitude of the e.m.f. source, and on the device or devices through which
the current is flowing. The voltage-to-current ratio is called the resistance, R.
The unit of resistance is the ohm (symbol ). A resistance of 1 will
have a current of 1 A flowing through it when the potential difference across
it is 1 V. So
V
.
R
For most electrical devices the current is not proportional to the voltage
because the resistance varies with the current. However, devices having a
more or less constant value of resistance over the widest possible range of
operating conditions are called
resistors.
7
Connecting
Wires
Color Bands
to Identify
Resistance
Value
Carbon Composition
Resistance Element
Protective
Insulating Sheath
Fig. 1.1. Typical resistor structure
Figure 1.2 shows a voltage/current graph for a resistor that would be a
straight line through the origin, where the slope of the line is the resistance.
Practical resistors have nearly constant resistance and almost a linear
voltage/current graph. Real resistors are usually very close to linear ones
when they are operated within their intended range. But they show nonlinear
behavior outside this range. The main reason for this is that in most cases a
resistor is operated in a region where it has to absorb too much power, thus it
gets too hot or even burns up.
R1< R
I
V
1V2
2
V
Fig. 1.2. Volt-Ampere Characteristic of Resistors
The physicist Ohm stated in his law that ‘the current flowing in an
electrical conductor is proportional to the voltage across it at constant
temperature’, and it is written in the form
.VIR
8
Current and voltage in a circuit or device can be related in an alternative
R
way, i. e. the ratio I/V is used instead of V/I. The ratio I/V is called the
conductance of the circuit, symbol G:
I
G
.
V
The conductance unit is the
siemens (symbol S). A resistor whose
conductance is 1 S, through which a current of l A is flowing, has 1 V
potential difference across it.
Thus, the relationship between the ohm and the siemens is
1
G
or
1
.R
G
You can choose either expression. Resistance is more commonly used
than conductance, but there are cases when it is more convenient to use
conductance in calculations.
Conductors are made from the materials in which a small potential
difference can cause a large current flow. They therefore have very low
resistance and high conductance. The most commonly used conducting
material is copper; other electrical conductors are also pure metals such as arc
aluminium, silver, gold and platinum. A metal is a good conducting material
since it has huge numbers of mobile electrons. Not all conducting materials
are necessarily metals. But all metals are conductors.
Insulators are made from materials in which only a very weak current
flows, even in case of a great potential difference across them. They have
very high resistance and very low conductance. Common examples of
insulating materials are plastics, rubber, glass and ceramic materials. Air is
also an insulating material.
Some materials such as arc carbon, some metallic alloys and silicon
have neither good insulating properties nor good conducting properties.
Silicon is one of the materials known as
semiconductors which are used in
the manufacture of transistors and integrated circuits.
All materials change their characteristics, including the resistance, with
changes in temperature. Most conductors are subject to the resistance
increase when their temperature rises. They are said to have a positive
temperature coefficient of resistance. In semiconductors and many
insulators the resistance decreases with the temperature increase and they are
said to have a negative temperature coefficient.
Some components have a voltage/current graph which is not a straight
line even at constant temperature. The example is the graph of the current
against the voltage for a junction diode.
9
Though the resistance value for many devices is not a constant, the d.c.
resistance at any chosen current is still equal to the ratio of the voltage drop
to the current flowing, and the conductance is inverse to the resistance.
For the junction diode, we often refer to the value of the ratio of a
change in voltage,
called the
1.2.2. Internal Resistance and Output Voltage of an E.M.F. Source
terminals of the device is reduced when the current is removed from the
device. An ideal e.m.f. source should have a voltage which is independent of
the current. When making circuit calculations it is important to consider the
difference between real devices and the ideal model of an e.m.f. source.
Taking into account this voltage change, we say that the e.m.f. source has an
internal resistance.
V
B
incremental resistance, or the small-signal resistance.
With any practical e.m.f. source, the voltage that can be measured at the
V, to the resulting change in current, I. This ratio is
R
I
S
I
R
V
S
V
B
R
Fig. 1.3. Internal resistance in the circuit
In the equivalent circuit, the two quantities VS and RS are separated.
So in this case the symbol for the source represents an ‘ideal’ (i. e.
resistanceless) source of e.m.f. V
with it.
The battery performance in the circuit is the following. When an
external load resistor R is connected to the battery, as shown in fig. 1.3, the
current flows around the circuit. There will be a potential difference V
across an internal resistance R
current and the resistance, namely IR
(i. e., the voltage which can be measured across the terminals) will be
So the terminal voltage falls as the current increases. This is the effect
that the equivalent circuit is designed to represent.
. Its internal resistance is then in series
S
, and its magnitude will be the product of the
S
. The terminal voltage of the battery
S
VVIR
BS S
10
R
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