Electronic Circuits

Fundamentals & Applications

Mike Tooley

• Publisher: Routledge
• Year: 2015
• eBook ISBN: 9781317572329
• Edition: 4
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Electronics explained in one volume, using both theoretical and practical applications.

• New chapter on Raspberry Pi

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• Companion website contains free electronic tools to aid learning for students and a question bank for lecturers

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• Practical investigations and questions within each chapter help reinforce learning

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Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The fourth edition now offers an even more extensive range of topics, with extended coverage of practical areas such as Raspberry Pi.

The book's content is matched to the latest pre-degree level courses (from Level 2 up to, and including, Foundation Degree and HND), making this an invaluable reference text for all study levels, and its broad coverage is combined with practical case studies based in real-world engineering contexts. In addition, each chapter includes a practical investigation designed to reinforce learning and provide a basis for further practical work. A new companion website at www.key2electronics.com offers the reader a set of spreadsheet design tools that can be used to simplify circuit calculations, as well as circuit models and templates that will enable virtual simulation of circuits in the book. These are accompanied by online self-test multiple choice questions for each chapter with automatic marking, to enable students to continually monitor their own progress and understanding. A bank of online questions for lecturers to set as assignments is also available.

Chapter 1
Electrical fundamentals

Chapter summary

This chapter has been designed to provide you with the background knowledge required to help you understand the concepts introduced in the later chapters. If you have studied electrical science, electrical principles or electronics beyond school level then you will already be familiar with many of these concepts. If, on the other hand, you are returning to study or are a newcomer to electronics or electrical technology this chapter will help you get up to speed.

Fundamental units

You will already know that the units that we now use to describe such things as length, mass and time are standardized within the International System of Units. This SI system is based upon the seven fundamental units (see Table 1.1).

Derived units

All other units are derived from these seven fundamental units. These derived units generally have their own names and those commonly encountered in electrical circuits are summarized in Table 1.2 together with the corresponding physical quantities.

If you find the exponent notation shown in Table 1.2 a little confusing, just remember that V⁻¹ is simply 1/V, s⁻¹ is 1/s, m⁻² is 1/m⁻², and so on.

Example 1.1

The unit of flux density (the Tesla) is defined as the magnetic flux per unit area. Express this in terms of the fundamental units.

Solution

The SI unit of flux is the Weber (Wb). Area is directly proportional to length squared and, expressed in terms of the fundamental SI units, this is square metres (m²). Dividing the flux (Wb) by the area (m²) gives Wb/m² or Wb m⁻². Hence, in terms of the fundamental SI units, the Tesla is expressed in Wb m⁻².

Table 1.1 SI units

Quantity	Unit	Abbreviation
Current	ampere	A
Length	metre	m
Luminous intensity	candela	cd
Mass	kilogram	kg
Temperature	Kelvin	K
Time	second	s
Matter	mol	mol

(Note that 0 K is equal to -273 °C and an interval of 1 K is the same as an interval of 1 °C.)

Table 1.2 Electrical quantities

Quantity	Derived unit	Abbreviation	Equivalent (in terms of fundamental units)
Capacitance	Farad	F	A s V^-1
Charge	Coulomb	C	A s
Energy	Joule	J	N m
Force	Newton	N	kg m s^-1
Frequency	Hertz	Hz	s^-1
Illuminance	Lux	lx	lm m^-2
Inductance	Henry	H	V s A^-1
Luminous flux	Lumen	lm	cd sr
Magnetic flux	Weber	Wb	V s
Potential	Volt	V	W A^-1
Power	Watt	W	J s^-1
Resistance	Ohm	Ω	V A^-1

Example 1.2

The unit of electrical potential, the volt (V), is defined as the difference in potential between two points in a conductor which, when carrying a current of one amp (A), dissipates a power of one watt (W). Express the volt (V) in terms of joules (J) and coulombs (C).

Solution

In terms of the derived units:

Note that: watts = joules/seconds and also that amperes × seconds = coulombs

Alternatively, in terms of the symbols used to denote the units:

Hence, one volt is equivalent to one joule per coulomb.

Measuring angles

You might think it strange to be concerned with angles in electrical circuits. The reason is simply that, in analogue and a.c. circuits, signals are based on repetitive waves (often sinusoidal in shape). We can refer to a point on such a wave in one of two basic ways, either in terms of the time from the start of the cycle or in terms of the angle (a cycle starts at 0° and finishes as 360° (see Fig. 1.1)). In practice, it is often more convenient to use angles rather than time; however, the two methods of measurement are interchangeable and it’s important to be able to work in either of these units.

In electrical circuits, angles are measured in either degrees or radians (both of which are strictly dimensionless units). You will doubtless already be familiar with angular measure in degrees where one complete circular revolution is equivalent to an angular change of 360°. The alternative method of measuring angles, the radian, is defined somewhat differently. It is the angle subtended at the centre of a circle by an arc having length which is equal to the radius of the circle (see Fig. 1.2).

You may sometimes find that you need to convert from radians to degrees, and vice versa. A complete circular revolution is equivalent to a rotation of 360° or 2π radians (note that π is approximately equal to 3.142). Thus one radian is equivalent to 360/2π degrees (or approximately 57....

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• A note for teachers and lecturers
• A word about safety
• 1 Electrical fundamentals
• 2 Passive components
• 3 D.C. circuits
• 4 Alternating voltage and current
• 5 Semiconductors
• 6 Power supplies
• 7 Amplifiers
• 8 Operational amplifiers
• 9 Oscillators
• 10 Logic circuits
• 11 Microprocessers
• 12 The 555 timer
• 13 Test equipment and measurements
• 14 Fault finding
• 15 Sensors and interfacing
• 16 Circuit simulation
• 17 The PIC microcontroller
• 18 Electronic applications and the Raspberry Pi
• 19 Circuit construction
• Appendix 1 Student assignments
• Appendix 2 Revision problems
• Appendix 3 Answers to problems with numerical solutions
• Appendix 4 Semiconductor pin connections
• Appendix 5 1N4148 data sheet
• Appendix 6 2N3904 data sheet
• Appendix 7 Decibels
• Appendix 8 Mathematics for electronics
• Appendix 9 Useful web addresses
• Appendix 10 A low-cost bench power supply
• Index