Analog Electronics Applications

Fundamentals of Design and Analysis

Hernando Lautaro Fernandez-Canque

• Publisher: CRC Press
• Year: 2016
• Print ISBN: 9781498714952
• eBook ISBN: 9781315354071
• Topic: Computer Science
• Subtopic: Computer Networking
• Index: Computer Science

This comprehensive text discusses the fundamentals of analog electronics applications, design, and analysis. Unlike the physics approach in other analog electronics books, this text focuses on an engineering approach, from the main components of an analog circuit to general analog networks. Concentrating on development of standard formulae for conventional analog systems, the book is filled with practical examples and detailed explanations of procedures to analyze analog circuits. The book covers amplifiers, filters, and op-amps as well as general applications of analog design.

1	Analog Electronics Applications and Design

1.1INTRODUCTION TO ANALOG ELECTRONICS

Humans experience sound, vision, smell, hearing, or any external physical stimuli in form. In general, the natural physical world is analog. A physical stimulus can be transformed into an electronic signal using a transducer; and outputs of transducers are, in general, analog electronic signals. In this sense, humans cannot totally eliminate the manipulation of analog signals. With the advancement in semiconductor technology it has become possible to create millions of efficient electronic components of small physical size that utilize very little energy to operate as integrated circuits. The availability of integrated circuits with huge numbers of components provide the potential for creating robust reliable electronic applications that can embed ways of testing the circuit for functionality. This in turn can make the manufacture of applications easier.

Transistors can be made to operate in two states, saturation and cut off, to provide output voltages at two defined levels (zero and one). Subsequently, digital electronics was born and the manipulation of signals was made easier at an ultrafast rate and the number of signals to manipulate increased exponentially. Machines can communicate with each other in digital form but when human interference is required analog systems continue to be necessary.

Analog electronics has been replaced by digital electronics in many fields, media and communication in particular, but with the advancement of digital electronics it is necessary to match these advances with developments in analog electronics. Trends of pulses in digital form at a very high speed resemble an analog signal. To obtain a detailed analysis of circuitry manipulating these ultrafast signals, analog electronic theory is needed. Analog electronics is still a vibrant part of electronics to accompany and complement digital electronics and electrical power.

1.2ANALOG SIGNALS

An electronic analog signal provides the variation of a quantity such as voltage or current, with time, in a continuous fashion. In an analog signal waveform there is no discontinuity of values and there is no abrupt or large variation from one value to the next. A digital waveform differs from an analog waveform in that the digital waveform has only well-defined steps values kept at different periods of time. The transition between the two steps is assumed to be instantaneous. Figure 1.1 shows a sample of an analog signal and a binary digital signal.

In the analog waveform represented in Figure 1.1a the analog voltage value at times t₁, t₂, t₃, and t₄ are different values of voltage. At any particular time, values of voltages in the proximity are close in value to the value at this particular time and show a continuous change. In the digital waveform represented in Figure 1.1b, there are only two values of voltages: 0 or 3 V. Therefore, at different times the voltages can be only 0 or 3 V. The voltages at times t_a, t_c, and t_e are 0 V and the voltage at times t_b, t_d, and t_f are 3 V. The value at t_X shows a discontinuity because in theory it can be 0 or 3 V and it can change instantaneously from 0 to 3 V. Then an analog signal is any continuous signal for which the time-varying characteristic of the signal (usually voltage, current, or power) is represented as a function of time or some other time-varying quantity.

FIGURE 1.1Example of (a) analog and (b) digital signals.

Electronic systems that can manipulate analog signals are termed analog systems.

1.3ANALOG SYSTEMS

An electronic system is an assembly of electronic devices and components connected in order to respond to a defined input or inputs so as to produce the desired output or outputs. Electronic systems have characteristics that accept the input or inputs and manipulate them to create the desired output signal or signals. A good electronic system is one that has been designed to solve a particular problem in the most appropriate and efficient way.

In this chapter, we look at various approaches to system design and note the benefits of adopting a methodical, rational approach. We also consider the various stages of system design, briefly discuss the choice of the technology to be used, and consider various automated design tools.

Many systems take as their input some physical quantities and produce as their output a variation in these physical quantities. Figure 1.2 shows a block diagram of such system.

In an electronic system, we normally sense the physical input quantity using some form of sensor, transducer, or actuator that generates an electrical signal correlated to the physical input. In the same way, in a system the output quantity is usually uninhibited by a sensor, transducer, actuator, or display that is controlled by the electronic output from the electronic system. Considering the sensors, transducers, and actuators, the inputs and outputs will be related to the external physical quantities concerned. By allowing for the sensors, transducers, and actuators to be external to the electronic system, the input and output of an electronic system will be electronic signals.

FIGURE 1.2Electronics system as part of a complete system.

In many cases, electronic systems are used mainly because they deliver an economical solution, in some cases electronic systems provide the only solution. The processing and operations required by an electronic system will vary with the nature of the input signals and output signals and the required global function. The processing and operations required by an electronic system can include: amplification, addition, subtraction, integration, differentiation, filtering, counting, timing, signal generation, etc.

A designer of an electronic system has to be able to analyze a circuit so as to predict its electronic behavior. To design and construct the circuits included in an electronic system, the designer should also be able to select suitable components in terms of value, tolerance, voltage, current, power rating, and cost.

In order to create or implement an analog electronic application it is necessary to be able to analyze circuits used. Design and implementation of an application of analog electronics goes hand in hand. In both cases, knowledge of the fundamentals of electronics is required. Knowing the fundamentals of electronics will allow a designer or practitioner to predict the behavior of a circuit or modify an existing circuit as well as create and improve an electronic system.

A design methodology will be a concept that students can become familiar with as they learn about existing systems and how they work. Complex systems can be made easier to understand if broken down. A range of steps is necessary to successfully conclude the realization of an electronic design system.

1.4APPLICATION AND DESIGN OF ANALOG SYSTEMS

An electronic system can be represented as a closed structure for which all the inputs and outputs are known. In practice, we select and choose to enclose a component, or group of components, that are of specific interest to us.

1.4.1CUSTOMER REQUIREMENTS

An important part of the process of designing an application is determining precisely the requirements of the user or customer. The final user of the electronic system will, in many cases, articulate their requirements in nontechnical or imprecise terms. It is imperative at this stage to clarify exactly what the system will do and at what range of variables. The designer and customer must agree on what is required from the system. This agreement will create a contract wherein the designer will design an electronic system to satisfy this contract. The designer will convert these requirements into the technical system design specifications.

1.4.2TOP-LEVEL SPECIFICATIONS

A top-level specification considers the system as a global entity. A top-level specification looks at characteristics that are features of the entire system, rather than of individual components. These properties are often complex in nature, and may relate to several diverse aspects of the system. The top-level specifications determine what the system is to do without taking into consideration how to do it. This task will produce a global arrangement for the system. The top-level specifications must define precisely what the system should do in response to all possible inputs, and must also establish any restrictions on the design of the electronic system. The top-level s...

Table of contents

• Cover
• Title
• Copyright
• Dedication
• Contents
• Preface
• Acknowledgments
• Author
• Chapter 1 Analog Electronics Applications and Design
• Chapter 2 Electric Circuits
• Chapter 3 Circuit Analysis
• Chapter 4 Diodes
• Chapter 5 Bipolar Junction Transistor
• Chapter 6 Field Effect Transistors
• Chapter 7 Bipolar Junction Transistor Biasing
• Chapter 8 Modeling Transistors
• Chapter 9 Small-Signal Analysis of an Amplifier under Different Models
• Chapter 10 Amplifiers Frequency Response
• Chapter 11 Common Collector Amplifier/Emitter Follower
• Chapter 12 Common Base Amplifier
• Chapter 13 Common Emitter Amplifier in Cascade
• Chapter 14 Field Effect Transistor Biasing
• Chapter 15 Field Effect Transistor as Amplifiers
• Chapter 16 Transfer Function and Bode Diagrams
• Chapter 17 Feedback in Amplifiers
• Chapter 18 Differential Amplifiers
• Chapter 19 Operational Amplifiers
• Chapter 20 Filters
• Chapter 21 Applications of Analog Electronics
• Chapter 22 Future Trend of Analog Electronics
• Chapter 23 Computer-Aided Simulation of Practical Assignment
• Index