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AnalogElectronic Circuits

For B.E. / B.Tech Students of Punjab Technical University (PTU)and H.P. Technical University (HPTU)

Dr. R.S. SEDHAPh.D. (U.K.); M. Tech. (IIT Delhi); Life Fellow IETE (Delhi), MIEEE

School of EngineeringRepublic Polytechnic

SINGAPORE

S. CHAND & COMPANY LTD.(An ISO 9001 : 2008 Company)Head Office: 7361, RAM NAGAR, NEW DELHI - 110 055Phone: 23672080-81-82, 9899107446, 9911310888Fax: 91-11-23677446Shop at: schandgroup.com; e-mail: [email protected]

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© 2012, Dr. R.S. SedhaAll rights reserved. No part of this publication may be reproduced or copied in any material form (including photocopying or storing it in any medium in form of graphics, electronic or mechanical means and whether or nottransient or incidental to some other use of this publication) without written permission of the copyright owner.Any breach of this will entail legal action and prosecution without further notice.Jurisdiction : All desputes with respect to this publication shall be subject to the jurisdiction of the Courts,tribunals and forums of New Delhi, India only.

First Edition 2012

ISBN : 81-219-3950-X Code : 10 525

PRINTED IN INDIA

By Rajendra Ravindra Printers Pvt. Ltd., 7361, Ram Nagar, New Delhi -110 055and published by S. Chand & Company Ltd., 7361, Ram Nagar, New Delhi -110 055.

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I take an opportunity to present this book “Analog Electronic Circuits” to the students

of Punjab Technical University (PTU) and Himachal Pradesh Technical University (HPTU).

The book covers topics from the syllabus of “Analog Electronics/Analog Electronic

Circuits” subject.

The objective of this book is to present the subject matter in a more concise, compact,

to the point and in lucid manner, while writing this book, I have constantly kept in mind the

requirements of all the students (who are academically good as well as those who are

academically challenged), latest examination questions of PTU and HPTU. The book has

been written in an easy style with full details and illustration. It will help the students to

grasp good understanding of the concepts as well as will help to prepare well for the

examination and score well.

All along the approach to the subject matter, every care has been taken to arrange the

matter from simple to harder, known to unknown, in a self-study style.

Dr. R.S. SEDHASingapore

e-mail: [email protected]

PREFACE

Disclaimer : While the author of this book have made every effort to avoid any mistake or omission and have used their skill,expertise and knowledge to the best of their capacity to provide accurate and updated information. The author and S. Chand doesnot give any representation or warranty with respect to the accuracy or completeness of the contents of this publication and areselling this publication on the condition and understanding that they shall not be made liable in any manner whatsoever. S.Chandand the author expressly disclaim all and any liability/responsibility to any person, whether a purchaser or reader of this publicationor not, in respect of anything and everything forming part of the contents of this publication. S. Chand shall not be responsible for anyerrors, omissions or damages arising out of the use of the information contained in this publication.Further, the appearance of the personal name, location, place and incidence, if any; in the illustrations used herein is purelycoincidental and work of imagination. Thus the same should in no manner be termed as defamatory to any individual.

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SYLLABUS FOR PTU

EC-202 ANALOG ELECTRONICSInternal Marks : 40External Marks : 60Total Marks : 100

1. HIGH FREQUENCY TRANSISTORThe high frequency T-model, common base short circuit current frequency response, alpha cut-offfrequency, common emitter short circuit current frequency response, hybrid π CE transistor model,hybrid π conductance in terms of low frequency h-parameters, CE short circuit current gain obtainedwith hybrid π model, current gain with resistive load.

2. LARGE SIGNAL AMPLIFIERSClass A direct coupled with resistive load, transformer coupled with resistive load, design theory,power amplifier design, harmonic distortion, power output, variation of output power with load,thermal runaway, output transformer saturation, push-pull amplifiers, operation of class-A push-pullamplifier, c1ass-B push-pull amplifier, crossover distortion, class AB push-pull amplifier, transistorphase invertor, conversion efficiency of class-B amplifiers, design or class-B push-pull amplifier,complementary-symmetry amplifier.

3. MULTISTAGE AMPLIFIERSCoupling of transistor amplifiers, frequency response of coupled amplifiers, cascading of RC coupledamplifiers and their analysis. Tuned Amplifiers: single tuned, double tuned and stagger tuned ampli-fiers and their analysis.

4. FEEDBACK IN AMPLIFIERSTypes of feedback, effect of negative feedback on gain, bandwidth, stability, distortion and frequencyresponse, etc. Voltage series, current series, voltage shunt, current shunt feedback circuits and theiranalysis.

5. OSCILLATORSConditions of oscillations. Different types of oscillators: RC Phase Shift, Wein Bridge, Hartley, Colpittsand Crystal Oscillators. Derivation of expression for frequency and amplitude of these oscillators.

6. REGULATED POWER SUPPLIESZener diode as Voltage Regulator, Transistor Series and Shunt Regulators, Current limiting, Line andLoad Regulation.

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ANALOG ELECTRONIC CIRCUITS EC-3003

SECTION-A

MULTISTAGE AMPLIFIERSGeneral cascaded systems, RC Coupled amplifiers, Transformers coupled amplifiers, direct-coupledamplifiers, cascaded amplifiers, Darlington compound configuration, Multistage frequency effects.

SECTION-B

HIGH FREQUENCY RESPONSE OF TRANSISTOR AMPHigh Frequency Model for CE amplifiers, approximate CE high frequency Model with resistive load,CE short circuit gain. HF Current gain with resistive load.

LARGE SIGNAL AMPLIFIERAnalysis and design of Class A, B, AB amplifiers, Push pull amplifiers, transforms less output stages,distortion calculations, high power amplifiers.

SECTION-C

TUNED AMPLIFIERSGeneral bahaviour of tuned amplifiers, Resonance, Series and parallel resonant circuit, calculationsof circuit impedance at resonance. Variation of impedance with frequency, Q-Factor of a circuit andcoil. Bandwidth of a series and parallel resonant circuit advantage and disadvantage of tuned ampli-fiers, single tuned amplifiers voltage gain and frequency response of single tuned amplifiers, doubletuned amplifiers, Analysis and design of Class-C amplifiers.

WIDE BAND AMPLIFIERSHigh frequency and low frequency Compensation, pulse rise-time and fall-time response, widebandamplifier using bipolar and FET devices.

SYLLABUS FOR HPTU, (SEMESTER-III)

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SECTION-D

FEEDBACK AMPLIFIERSFeedback concept, characteristics of negative and positive feedback. Effect on I/P & O/P impedances,gain frequency response and noise.

REGULATED POWER SUPPLIESUnregulated power supplies, Zener diode voltage regulators, and transistor series and shunt regulators.OPAMP voltage regulators, IC voltage regulators. Introduction to SMPS.

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1. INTRODUCTION 1–51.1 Definition; 1.2 Beginning and Developoment of Electronics; 1.3 Modern Trendsifn Electronics; 1.4 Applications of Electronics; 1.5 Communication andEntertainment Applications; 1.6 Instrumentations and Control Applications;1.7 Defence Applications; 1.8 Applications in Medicine; 1.9 Computer Aided Designof Electronic Circuits; 1.10 Careers in the field of Electronics.

2. HIGH FREQUENCY RESPONSE OF A TRANSISTOR 6–36

2.1 Introduction; 2.2 General Frequency Consideration; 2.3 Normalized Gain-versusFrequency Plot; 2.4 Low-Frequency Analysis; 2.5 Determination of Gain from theFrequency Plot; 2.6 The high frequency T model; 2.7 Low-Frequency Response ofBJT Amplifier; 2.8 Miller Effect Capacitance; 2.9 High Frequency Response ofBJT Amplifier; 2.10 Low Frequency Hybrid-p Model of transistor; 2.11 Hybrid-pconductance in terms of low frequency h parameters; 2.12 High Frequency Hybrid-π Model of a transistor; 2.13 Common Emitter short circuit with Hybrid-π; model.

3. LARGE SIGNAL AMPLIFIERS 37–663.1 Introduction; 3.2 Difference between Voltage Amplifier and Power Amplifier;3.3 Performance Parameters; 3.4 Harmonic Distortion; 3.5 Classification of PowerAmplifiers; 3.6 Class-A Amplifier; 3.7 Characteristics of Class-A Amplifier;3.8 Power Relations for Class-A Amplifier; 3.9 Overall and Collector Efficiency ofClass-A Amplifier; 3.10 Transformer Coupled Class-A Amplifier; 3.11 Class-BAmplifier; 3.12 Characteristics of Class-B Amplifier; 3.13 Power Relations for Class-B Amplifier; 3.14 Maximum value of A.C. Output Power in Class-B Amplifier;3.15 Maximum Overall Efficiency for Class-B Amplifier; 3.16 Class-B PushPullAmplifier; 3.17 Advantages of Class-B Push-Pull Amplifier; 3.18 CrossoverDistoration; 3.19 Efficiency of Class-B Push-Pull Amplifier; 3.20 TransformerlessClass-B Push-Pull Amplifier; 3.21 Complementary Symmetry Class-B Push-PullAmplifier; 3.22 Class-AB Amplifier; 3.23 Class-AB Push Pull Amplifier; 3.24 Class-C Amplifier; 3.25 Characteristics of Class-C Amplifier.

4. MULTI-STAGE AMPLIFIERS 67–954.1 Introduction; 4.2 Gain of a Multistage Amplifier; 4.3 Different Coupling SchemesUsed in Amplifiers; 4.4 RC Coupled Amplifier; 4.5 Calculation of Voltage Gain forRC Coupled Amplifier; 4.6 Frequency Response of RC Coupled Amplifier;

CONTENTS

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4.7 Advantages and Disadvantages of RC Coupled Amplifier; 4.8 Application ofRC Coupled Amplifier; 4.9 Impedance Coupled Amplifier; 4.10 Transformer CoupledAmplifier; 4.11 Calculations of Voltage Gain for Transformer Coupled Amplifier;4.12 Frequency Response of Transformer Coupled Amplifier; 4.13 Advantages andDisadvantages of Transformer coupled Amplifier; 4.14 Applications of TransformerCoulped Amplifier; 4.15 Direct Coupled Amplifier; 4.16 Calculations of VoltageGain for Direct Coulped Amplifier; 4.17 Direct Coulped Amplifier UsingComplementary Transistors; 4.18 Frequency Response of Direct Coupled Amplifier;4.19 Advantages and Disadvantages of Direct Coupled Amplifier; 4.20 Applicationsof Direct Coupled Amplifier; 4.21 Darlington Amplifier; 4.22 Darlington AmplifierCharacteristics; 4.23 Darlington Pair; 4.24 Multistage Frequency Effects.

5. TUNED AMPLIFIERS 96–1075.1 Introduction; 5.2 Parallel Resonant Circuit; 5.3 Resonance Curve; 5.4 Bandwidthof a Parallel Resonant Circuit; 5.5 Sharpness of Resonance; 5.6 Single-tuned VoltageAmplifier; 5.7 Frequency Response of Single-tuned Voltage Amplifier;5.8 Limitations of Single-tuned Voltage Amplifier; 5.9 Double-tuned VoltageAmplifier; 5.10 Frequency Response of Double-tuned Voltage Amplifier 5.11 Stagger-tuned Voltage Amplifier; 5.12 Class C-tuned Amplifier.

6. FEEDBACK IN AMPLIFIERS 108–1316.1 Introduction; 6.2 Principle of Feedback Amplifiers; 6.3 Advantages of NegativeFeedback; 6.4 Gain Stability; 6.5 Increased Bandwidth; 6.6 Decreased Distortion;6.7 Decreased Noise; 6.8 Types of Feedback Connections; 6.9 Voltage-SeriesFeedback Connection; 6.10 Voltage-Shunt Feedback Connection; 6.11 Current-seriesFeedback Connection; 6.12 Current-Shunt Feedback Connection; 6.13 Comparisonof Feedback Connections; 6.14 Negative Feedback of Transistor Amplifiers;6.15 Common Emitter Amplifier without Emitter Bypass Capacitor; 6.16 EmitterFollower; 6.17 Collector Feedback Biased Commnon Emitter Amplifiers;6.18 Negative Feedback in Multistage Amplifiers.

7. OSCILLATORS 132–1637.1 Introduction; 7.2 Comparison between an amplifier and an Oscillator;7.3 Classification of Oscillator; 7.4 Applications of Sinusoidal Oscillators; 7.5 Natureof Sinusoidal Oscillations Oscillatory Circuit; 7.6 Frequency of Oscillator Circuit;7.7 Frequency Stability of an Oscillator; 7.9 The Barkhausen Criterion; 7.10 RCOscillators; 7.11 Basic Principle of RC Oscillators; 7.12 RC Phase-Shift Oscillator;7.13 Transistor Phase Shift Oscillator; 7.14 Wien-Bridge Oscillator; 7.15 HartleyOscillator; 7.16 Colpitts Oscillator; 7.17. FET Colpits Oscillator; 7.18 CrystalOscillator; 7.19 Quartz Crystal; 7.20 Characteristics of Quartz crystal; 7.21 ElectricalEquivalent Circuit of a Crystal; 7.22 Q-Factor and Frequency Stability of a Crystal;7.23 Crystal Oscillator Circuit.

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8. REGULATED POWER SUPPLY 164–2058.1 Introduction; 8.2 Voltage Regulator; 8.3 Voltage Regulation; 8.4 Types of VoltageRegulators; 8.5 Zener Diode Shunt Regulator; 8.6 Working of Zener Diode ShuntRegulator; 8.7 Optimum Value of Current Limiting; 8.8 Disadvantages of ZenerDiode Resistor Shunt Regulator; 8.9 Transistor Shunt Regulator; 8.10 TransistorSeries Regulator; 8.11 Controlled Transistor Series; 8.12 Short-circuit ProtectionAgainst Regulator Overload; 8.13 Transistor Current Regulator; 8.14 VariableFeedback Regulator; 8.15 Basic Op-amp Series Regulator; 8.16 Basic Op-amp ShuntRegulator; 8.17 Switching Regulators; 8.18 Step-down Switching Regulator;8.19 Step-up Switching Regulator; 8.20 Inverting Switching Regulator; 8.21 ICVoltage Regulators; 8.22 Fixed Positive Linear Voltage Regulators; 8.23 FixedNegative Linear Voltage; 8.24 Adjustable Positive Output Linear Regulators VoltageRegulators; 8.25 Adjustable Negative Output Linear; 8.26 Use of External PassTransistor with Linear Voltage Regulators; 8.27 Use of Linear Voltage Regulatorsas a Current Regulators; 8.28 Switching Voltage IC Regulators; 8.29 Complete d.c.Power Supply Circuit; 8.30. Introduction to SMPS.

●●●●● APPENDIX 206–207 A- Resistor values 206

B-Capacitor Values 207

●●●●● INDEX 208–209

11.1 DEFINITION The word ‘electronics’ has been derived from a Greekword ‘elektron’, which means the study of behaviourof an electron under different conditions of externallyapplied fields. The Institution of Radio Engineers(IRE) has given a standard definition of electronicsin the proceedings of I.R.E. Vol. 38 (1950) as thatfield of science and engineering, which deals withthe study, design and use of devices, which dependson the conduction of electricity through a vacuum,gas or semiconductor. Until recently, it was consid-ered as an integral part of Electrical Engineering. Butdue to its tremendous advancement, during the lastfew decades, it has achieved its own place in the fieldof science and technology.

These days, the field of electronics has becomethe most important branch of engineering in oursociety. As a matter of fact, it is a field, in which rapiddevelopments are taking place every day. Theelectronic devices and gadgets are being used inalmost all industries for quality control andautomation. Because of the growing applications ofelectronics, in almost all fields, the students of allengineering disciplines have to be taught electronicsat the undergraduate level.

IntroductionC H A P T E R

OUTLINE1.1 Definition.1.2 Beginning and Development of

Electronics.1.3 Modern Trends in Electronics.1.4 Applications of Electronics.1.5 Communication and Entertainment

Applications.1.6 Instrumentations and Control

Applications.1.7 Defence Applications.1.8 Applications in Medicine.1.9 Computer Aided Design of Electronic

Circuits.1.10 Careers in the field of Electronics.

OBJECTIVESAfter completing this chapter, you shouldbe able to :

! Know the definition of electronics! Describe applications of electronics

in the field of communication,defense, industry and medicine

! Identify different electronic designautomation (EDA) tools for designingand simulating electronic circuits.

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2 ANALOG ELECTRONIC CIRCUITS

1.2 BEGINNING AND DEVELOPMENT OF ELECTRONICS The era of electronics is believed to have dawned with the experiments involving electric currents inglass vacuum tubes. Such experiments were performed around 1850 by a German scientist namedGeissler. He found that if the air is removed from a glass tube, it glows when an electric current passesthrough it. Around 1878. British scientist, Sir William Crookes found that the current in vacuum tubesseemed to consist of particles.

As a matter of fact, the electron was discovered in the 1890’s. A French physicist, Perrindemonstrated that current in a vacuum tube consists of the movement of negatively charged particlesin a given direction. Some of the properties of these particles were measured by a British physicistThomson. These negatively charged particles were later on, named as electrons. An American physicist,Milikan, in 1909 measured the charge on an electron. As a result of these discoveries, the movementof electrons could be controlled, and thus the electron era started.

Fleming, in 1904, invented a vacuum tube that allowed electrical current only in one direction.This tube was named as Fleming valve or diode vacuum tube and used to detect electromagneticwaves. In 1907, Lee deForest, an American scientist invented a tube, which could amplify weakelectrical a.c. signals. This tube was named as triode vacuum tube.

Around 1915, few great improvements were made in the triode vacuum tube. It was used inoscillator circuit. It was also used in telephone system, which made possible the communicationbetween the different continents. The tetrode was invented in 1916 by a German engineer and apentode was invented in 1926 by a Dutch engineer. The tetrode, alongwith the pentode, greatly improvedthe triode. The first television picture tube, called the kinescope, was developed in 1920’s by anAmerican researcher.

Several types of microwave tubes were developed during the World War II. Such tubes madepossible the modern RADAR and other communication systems. The magnetron was invented inBritain in 1939. In the same year, klystron microwave tube was developed by two Americans. Thetravelling wave tube (TWT) was invented in 1943 by an American scientist.

The era of solid state electronics began with the invention of transistor in 1947 at Bell laboratory.The inventors were Walter Britain, John Bardeen and William Shockley. The transistors were producedcommercially in 1951. The companies like RCA, Raythesn, General Electric, Westinghouse andWestern Electric were the first to fabricate transistors.

In 1958, it was thought that germanium and silicon can be used to build an entire circuit, calledmonolithic circuit. Resistors were formed with the bulk semiconductor or by diffusing onesemiconductor into another. The capacitors were formed by using a metallic layer and the semiconductorfor the plates and an oxide layer for the dielectric. In 1959, Noyce gave an idea for making multipledevices on a single piece of silicon, in order to make an interconnection between devices as part ofmanufacturing process. It could reduce the size, weight and cost per device. The monolithic-circuitwas named an integrated circuit (IC). The IC’s were produced, commercially in 1961 by Fairchildand Texas instruments.

1.3 MODERN TRENDS IN ELECTRONICS The development of an integrated circuit (IC) in 1961 was a great achievement in the field of electron-ics. But, as there is no end to the man’s desire, the growth accelerated further every year. Rapid develop-ments have been made in the integrated circuit technology. Thus starting from the *small-scale integra-tion (SSI) in 1961, then **medium-scale integration (MSI) in 1966, and ***large-scale integration(LSI) in 1970. Now in 1980’s we have a very large-scale integration (VLSI). It means that now we havea technology, which can fabricate about 1 million or more components on a single chip.

* It indicates that the number of components fabricated on a single-chip was less than 100.** It indicates that the number of components fabricated on a single-chip was 100 to 1000.

*** It indicates that number of components fabricated on a single-chip is between 1000 to 10,000.


INTRODUCTION 3

It will be interesting to know that the use of vacuum tube has become almost obsolete in 1960’s.It was replaced by the solid state devices (bipolar transistors and field-effect transistors). Similarlythe developments in integrated circuit technology, has made the use of individual transistors asunnecessary. These days, we see all electronic systems made of IC’s. The developments which, havetaken place in last 35 years, may be understood from the fact that today’s microcomputer is 1000times faster, has a large memory, thousands times more reliable, consumes negligible power, occupies1/30,000 the volume and costs 1/10 000 as compared to the first large electronic computer.

The microelectronics (term used for the fabrication of VLSI-circuits) has made a great impacton communication control and computer industries. The applications, which were difficult to realizeearlier, have now become possible. In last decade, silicon based technology has dominated the sphereof electronics and will continue to play the role for the next decade as well. However, after thatgallium arsenide (Gas) might play a significant role in electronics.

1.4 APPLICATIONS OF ELECTRONICS These days, we find that the sphere of electronics has spread so vast, that it plays an important role inalmost every activity of life. It has penetrated into our homes, our places of work and our means ofcommunication from one place to another. It is believed that by the end of this century, the electronicswill be like the electric motor of today (i.e., its presence will go unnoticed). Although, electronics hasa large number of applications, yet the following are important from the subject point of view:

1. Communication and entertainment applications.2. Instrumentation and control applications.3. Defence applications.4. Applications in medicine.5. Computer-aided design of electronic circuits.

Now we shall discuss all these applications, in brief, in the following pages.

1.5 COMMUNICATION AND ENTERTAINMENT APPLICATIONS It will be interesting to know that in the beginning of 20th century, the electronics was used only in thefield of telephony and telegraphy. It required a pair of conductingwires. But, these days, we have cordless telephones and mobilephones which send or receive information from one place to an-other, without the use of any wire. Such a communication is knownas wireless communication. Todays, we have a push button tele-phones with memory. Such telephones can also record the mes-sages in the absence of its owner. It is possible to have video con-ference from anywhere on the earth, or infact millions of kilome-ters in space. It is surprising that someone sitting at a space centerin NASA/ISRO can instruct a space vehicle, million kilometersaway, to turn on its TV camera and send pictures back to the earth.

These days, the radio and television provide a means of communication, education andentertainment. The electronics gadgets like stereos, tape recorders, DVD players, MP-3 players and


4 ANALOG ELECTRONIC CIRCUITS

video games etc., are widely used for entertainment. The use of integrated circuits ICs have improvedboth the reliability and performance of radios and television receivers. It has also helped to bringdown their cost, because of the simple procedures adopted during the assembly stages.

We have digital cameras and digital camcorders where the still pictures/video can be stored ona memory stick (flash memory). The pictures can be downloaded to a computer to keep a record inalbums for sharing with the relatives and friends through the Internet. The MP-3 player can be used todownload the music from the Internet and listen at your convenience.

1.6 INSTRUMENTATION AND CONTROL APPLICATIONS The instrumentation plays an important role in our industry. It helps in precise measurement andtesting of a number of quantities of interest. The electronics is also playing an increasingly importantrole in instrumentation. The cathode ray oscilloscopes (CRO’s) frequency counters, pulse and signalgenerators, digital multimeters (DMM’s) power supplies etc., are some of the instruments, which arefound in every industry and research organisations.

The control industry has been drastically effected bythe introduction of semiconductor electronics. In some tra-ditional areas, such as motor speed control and power rec-tifiers and inverters, the silicon controlled rectifier (SCR)has replaced the gas filled tube (thyratron). Most of the con-trol systems, which are available today, are possible onlybecause of the recent dramatic advances in electronics. Thecontrol system designs, which were not practical earlier,because of the cost (only five years ago) are already be-coming obsolete today. The introduction of microproces-sors, microcomputers and digital integrated circuits has led to “smart” instruments and continuouslyincreasing variety of digital control systems. With microelectronics, the computers have becomeintegral component of our control systems.

1.7 DEFENCE APPLICATIONS The role of electronics in defence started with the introduction of RADAR during the World War II.The RADAR is an abbreviation used for Radio Detection and Ranging. A radar is capable of detect-ing and finding exact location of enemy aircraft. These days, we have aeroplanes, ships, anti-aircraftguns and guided missiles, underwater robots completely controlled by electronics.

1.8 APPLICATIONS IN MEDICINE These days, big hospitals and drug research organisations are utilising an increasing role of electronicinstrumentation. In many developed countries, the computers are used to hold patients records andassist in arriving at correct diagnosis. A large number of electronic instru-ments are also used in the diagnosis and treatment of various diseases. Someof the important ones are given below:

1. Electrocardiograph (ECG). It is used to find the condition of the heartof a patient.

2. X-ray equipment. It is used for taking pictures of internal bone structures.It is also used for the treatment of some diseases.

3. Ultrasound scanner. It is used to take pictures and examine the functionsof a brain, kidney etc. It is also used for the treatment of some diseases.

4. Electrical enceplograph (EEG). It is used for neurological investigations.5. Cathode ray oscilloscope. It is used for studying muscle actions within

the body.6. Magnetic Resonance Imaging (MRI). It is used for investigating

turmours or other defects within the body.


INTRODUCTION 5

1.9 COMPUTER-AIDED DESIGN OF ELECTRONIC CIRCUITS The circuit designers, of previous generations, used to build a circuit on printed boards, and thenstudy its performance. These days, it is possible to use a computer not only as a means of simulatinga particular system design, but also to model the effects of statistical variations in the manufacturingprocess. The computer is also used to optimise parameters in a given system design. It is also used tomeet some set of design objectives better and to explore various alternative designs. It is generallydone to determine the relative trade-off between the various competing objectives. These days, theVLSI (very large-scale integrated) circuits are designed by means of a computer. Even for a productdesign, the engineer can design the product in the computer, carryout the studies on various parametersby simulation on the computer. Rapid prototyping is also done by using computers.

There are several such tools available in the market, some of them with mentioning are ORCAD/PSPICO, Altera, Xilinx, Actel (non-Microsemi) and Quick Logic.

1.10 CAREERS IN THE FIELD OF ELECTRONICS The field of electronics is very diverse and career opportunities are available in many areas. Sinceelectronics is currently found in so many different applications ranging from toys to spacecrafts andnew technology is being developed at a very fast rate, its future appears limitless. There is hardly anyarea of our lives that is not enhanced to some degree by electronics technology. Those who acquire asound, basic knowledge of electrical and electronic principles and are willing to continue learningwill always be in demand.

The importance of obtaining a through understanding of the basic principles contained in thistext cannot be overemphasized. Most employers prefer to hire people who have both a throughgrounding in the basics and the ability and eagerness to grasp new concepts and techniques. If youhave a good training in basics, an employer will train you in the specifics of the job to which you areassigned.

There are many types of job classification for which a person with training in electronicstechnology may qualify. A few of the most common job functions are discussed briefly in the followingparagraphs.

Scientists and Engineers. Personnel in this category are involved in designing, prototypingand testing electronic systems in research and development laboratories during the development phaseof the product.

Industrial Manufacturing Engineers. Manufacturing personnel are involved in testing ofelectronic products at the assembly-line level or in the maintenance and trouble shooting of electronicand electromechanical system used in testing and manufacturing of products. Virtually every type ofmanufacturing plant, regardless of its product, uses automated equipment that is electronicallycontrolled.

Technical Sales and Marketing. Technically trained people are in demand as sales andmarketing representatives for high technology products. The ability both to understand technicalconcepts and to communicate the technical aspects of the product to a potential customer is veryvaluable. In this area, as in technical writing, competency in expressing yourself orally, and in writingis essential. Actually, being able to communicate well is very important in any technical job categorybecause you must be able to record data clearly and explain procedures, conclusions, and actionstaken so that others can readily understand what you are doing.

Technical Writers. These personal compile technical information and then use the informationto write and produce manuals and audiovisual materials. A broad knowledge of a particular systemand the ability to clearly explain its principles and operation are essential.

Besides this, the diploma engineering people can find job as a customer support officers, laboratorytechnician, field service technician, service-shop technician, engineering assistant and many more.


Analog Electronic Circuits

Publisher : SChand Publications ISBN : 9788121939508 Author : Dr. R. S. Sedha

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