PESIT - BANGALORE SOUTH CAMPUS PART A

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1 PESIT - BANGALORE SOUTH CAMPUS LESSON - PLAN FOR BASIC ELECTRONICS ENGG. Name of Faculty: Percentage of course Periods Reference/ Text books Topics covered Reference chapter covered Cumulative PART A Unit I 1-7 SEMICONDUCTOR DIODES AND APPLICATIONS T1-2.1,2.2,2.3,2.4:2.5,2.6,2.9, R1-20.1, 20.2, 20.3, 20.4, 20.8; T1-3.5, 3.6). p-n junction diode, Characteristics and Parameters, Diode approximations, DC load line, Temperature dependence of p-n characteristics, AC equivalent circuits, Zener diodes Half-wave diode rectifier, Ripple factor, Full-wave diode rectifier, Other fullwave circuits, Shunt capacitor - Approximate analysis of capacitor filters, Power supply performance, Zener diode voltage regulators, Numerical examples as applicable Unit II TRANSISTORS 8-13 T14.1,4.2,4.3,4. 4,4.5,4.6,5.1,5.2,5.3,5.4,5.5,5.7, 5.9 Bipolar Junction transistor, Transistor Voltages and currents, amplification, Common Base, Common Emitter and Common Collector Characteristics, DC Load line and Bias Point

2 Unit III BIASING METHODS Base Bias, Collector to Base Bias, Voltage divider Bias, Comparison of basic bias circuits, Bias circuit design, Thermal Stability of Bias Circuits (Qualitative discussions only). Unit IV OTHER DEVICES Silicon Controlled Rectifier (S.C.R), SCR Control Circuits, More S.C.R applications; Unijunction transistor, UJT applications, Junction Field effect Transistors(Exclude Fabrication and Packaging), JFET Characteristics, FET Amplifications, Numerical examples as applicable. PART B Unit V AMPLIFIERS & OSCILLATORS T1 8.2, 12.1, 12.3, 13.1, 13.7; R ,17.16, 17.17,17.18, Decibels and Half power points, Single Stage CE Amplifier and Capacitor coupled two stage CE amplifier(qualitative discussions only), Series voltage negative feedback and Additional effects of Negative feed back(qualitative discussions only), The Barkhausen Criterion for Oscillations, BJT RC phase shift oscillator, Hartley,Colpitts and crystal oscillator ( Qualitative discussions only) Numerical problems as applicable Unit VI INTRODUCTION TO OPERATIONAL AMPLIFIERS

3 T , 9.6 Ideal OPAMP, Saturable property of an OP AMP inverting and non inverting OPAMP circuits, need for OPAMP, Characteristics and applications voltage follower, addition, subtraction, integration, differentiation; Numerical examples as applicable Unit VII COMMUNICATION SYSTEMS T2-13.1, 13.2, 13.4, 13.5 Block diagram, Modulation, Radio Systems, Superhetrodyne Receivers, Numerical examples as applicable NUMBER SYSTEMS T214.1 to Introduction, decimal system, Binary, Octal and Hexadecimal number systems, addition and subtraction, fractional number, Binary Coded Decimal numbers Unit VIII DIGITAL LOGIC T2:.14.1 to Boolean algebra, Logic gates, Half-adder, Full-adder, Parallel Binary adder. Text Books: 1. Electronic Devices and Circuits: David. A. Bell; Oxford University Press, 5th Edn., Reference Books: 1. Electronic Devices and Circuits: Jacob Millman, Christos C. Halkias TMH, 1991 Reprint Electronic Communication Systems, George Kennedy, TMH 4 th Edition. 3. Digital Logic and Computer Design, Morris Mano, PHI, EEE. 4. Basic Electronics, RD Sudhaker Samuel, U B Mahadevaswamy, V. Nattarsu, Saguine-Pearson, 2007.

4 COURSE OVER VIEW UNIT - 1: SEMICONDUCTOR DIODES AND APPLICATIONS Introduction: A P-N junction formed between an N-type semiconductor and a p-type semiconductor. A semiconductor consisting of a p-n junction is a very useful device and is called the semiconductor diode. All semiconductor device consist of one or more p-n junction. Example: A transistor has two junctions. A silicon controlled rectifier (SCR) is a three junction device. On the p-side majority charge carriers are Holes and on N-side the majority charge carriers are free Electrons. The small region in the vicinity of the junction which has been depleted by mobile charges (electrons and holes) and has only immobile ions is called Depletion region or Transition region. Or space charge region. Barrier potential is created at the junction, with negative polarity on the p-side and positive polarity on N-side. The electric field produced by the barrier potential is sufficiently large to prevent any further movement of electrons and holes across the junction. Hence equilibrium is attained at the junction. The typical barrier potential for a germanium p-n junction is about 0.3volts and for silicon 0.7 volts. The voltage to be applied to suppress the barrier potential is called Cut in potential. The thickness of the depletion region is of the order of few microns. If an external voltage applied across a p-n junction such that (it decreases the width of depletion region) it neutralizes the barrier potential and causes conduction through the junction, then the p-n junction is said to be Forward biased. If an external voltage is applied across p-n junction such that the depletion layer widens and the barrier potential increases with the result that no conduction occurs, the junction is said to be Reverse biased. The general characteristics of a p-n junction are defined by the current equation. ID= Current through P-N junction

5 IS= Reverse saturation current VD= External bias voltage TK= temperature in K given as TK=C K= 11,000 where =1 for germanium and = 2 for silicon ID= IS[ e kvd/tk - 1] The p-n junction is also termed as Junction diode or Semiconductor diode Conversion of AC into DC is defined as rectification. if a single diode used for rectification, conduction occurs only during positive Half-cycles.This results in Half-wave rectification. For conduction to occur during both positive and negative half-cycles, it is necessary to use two or four diodes. This results in Full-Wave rectification. A filter circuit is a device which removes the AC component of rectifier output allows the DC component to reach the load. The most commonly used filter circuits are 1) Capacitor filter 2) Choke input filter(or L filter) 3) Capacitor input filter or filter A properly doped crystal diode which has a sharp break down voltage is known as Zener diode A zener diode is always reverse connected ie, it is always operated in reverse bias. A zener diode has sharp breakdown voltage called zener voltage Vz A zener diode can be used as a voltage regulator. Applications: Semiconductors diodes are used in construction of Half wave rectifiers, Full wave rectifiers, and as a detector component in communication circuits. Zener diode is used as voltage regulator. Points to be remember: Construction of Semiconductor diode, Forward bias, Reverse bias, Rectification Circuits and Simple Zener regulator circuit design.

6 UNIT - 2: TRANSISTORS Introduction: When a third doped element is added to a crystal diode in such a way that two p-n junctions are formed, the resulting device is known as a Transistor. Transistor is an electronic device capable of achieving amplification of weak signals. A transistor (PNP or NPN) has three sections Emitter, Collector and base. A transistor can be connected in a circuit in following three ways 1) Common Base configuration 2) Common emitter configuration 3) Common collector configuration The ratio of the collector current to the emitter current in common base configuration is called Current amplification factor (). The ratio of collector current to Base current in common emitter configuration is called Current amplification factor (). Relation between & :- = / 1 + and = / 1- Points to be remembered: Current amplification factors ( α, β, γ) UNIT - 3: BIASING METHODS Introduction: Temperature changes causes thermal runaway and change in the operating point of the transistor. Hence stabilization of operating point is necessary. What is biasing and need for biasing Various biasing circuits Stabilization factor Design and analysis of Base Bias circuit Design and analysis of Collector to Base Bias circuit Design and analysis of Voltage divider Bias circuit Thermal stability of bias circuits

7 UNIT 4: OTHER DEVICES Introduction: Silicon Controlled Rectifier is a PNPN device which is used for controlled rectification. SCR finds application in power electronic circuits. UJT and FET are the two devices which have many advantages over transistors. Silicon Controlled Rectifier is a PNPN device which is used for controlled rectification i.e. for given input voltage, by varying the triggering angle or firing angle the output voltage can be varied and which implies the speed of the motor also varies What is a Uni-directional device. SCR conducts only when forward biased Why SCR is called as a latching device? and V-I characteristics of SCR SCR can be turned-on by applying small gate voltage and once SCR goes to on-state, gate looses control and SCR stays in ON-state even if the gate supply is removed. As the gate voltage is increased, SCR goes to on-state at smaller breaker over voltages SCR Control Circuits: Half controlled, full controlled and semi and full converters Circuit diagram and waveforms of these circuits for R-load S.C.R applications Uni junction transistors : Advantages of UJT over transistors What is a current controlled and a voltage controlled device. V-I characteristics and applications of UJT What is a field effect transistor Differences and advantages of FET over BJT BJT is a current controlled device while FET is a voltage controlled device In each case the current of the output circuit is being controlled a parameter of the input circuit in one case a current level and in the other an applied voltage Symbols of FET, BJT and UJT. Source and drain characteristics of FET Applications of FET. Applications of UJT : Sawtooth generators, oscillators, phase control, timing circuits. Points to be remembered: Characteristics of UJT, SCR, FET and their applications.

8 UNIT -5: AMPLIFIERS AND OSCILLATORS Introduction: An amplifier circuit is one which strengthen a weak signal. It is used to recover a signal which is buried in noise. The transistor amplifier may be classified as 1) According to use: are basically voltage amplifier and Power amplifier 2) According to frequency capabilities: are Audio amplifier & Radio frequency amplifiers 3) According to coupling methods are R-C coupled amplifier and Transformer coupled amplifiers 4) According to method of operation: are Class A, Class B, Class C and Class AB amplifier. Applications: Used in Amplifier circuits ie., Audio, video, RF amplifiers. Used in digital circuits, used in Oscillator circuit construction. OSCILLATORS. Introduction: An oscillator is an electronic circuit that converts direct voltage into alternating voltage of a desired frequency and magnitude without the use of Mechanical moving parts. An oscillator requires the following circuit conditions to produce oscillations. An oscillator uses a transistor in a circuit to an ac output. It uses an oscillatory or tank circuit containing L and C or R and C to produce oscillations A feed back circuit to supply the energy to the tank circuit to sustain the output with out the need for a signal from a preceding stage. Feed back is the process of introducing apart of the output signal into the input. Two types of feedback are used in electronic circuit. They are i) positive feedback and ii) Negative feed back depending on whether the feedback signal adds up to the input signal or reduces the input signal. If the feedback signal is in phase with the input signal, the feed back is said to be Positive feedback or Regenerative feed back. Positive feedback increases the gain of an amplifier, but introduces small distortion and instability. Positive feed back is used in oscillators. The oscillators using RC network are used for generation of low frequency signals up to about 100 KHz. Where as LC network are used for generation of high frequency signals of the order of several Mega Hz.

9 The feed back network should provide 1) feedback signal 2) necessary phase shift to satisfy the Barkhausen criterion for oscillations. Different types of oscillator circuits are 1. RC phase shift oscillator 2. Colpitts oscillator 3. Hartley oscillator 4. Crystal oscillator Applications: Crystal oscillators are used in Transmitters; Hartley oscillators are used in receiver circuits. Points to be remembered: The meaning of positive feedback and negative feedback. Barkhausen criterion for oscillations and Different types of oscillator circuits construction and working. UNIT - 6: INTRODUCTION TO OPERATIONAL AMPLIFIER Introduction: An operational amplifier is a direct coupled high-gain amplifier. Usually consisting of one or more differential amplifiers and usually followed by a level transistor and an output stage. The output stage is generally a push-pull or push-pull complementary symmetry pair an op-amp is available as a single integrated circuit package. The operational amplifier is versatile device that can be used to amplify DC as well as Ac input signals and was originally designed for computing such mathematical functions as, Addition, Subtraction, Multiplication and Integration thus the name Operational amplifier. Characteristics of an ideal op-amp:- 1) The voltage gain is infinity 2) The Output impedance is zero 3) The band-width is infinity 4) The input impedance is infinity 5) When equal voltages are applied at the two input terminals the out is zero. 6) There is no change in characteristic feature, with change of temperature. Some important terms related to op-amp are 1. Input offset voltage

10 2. Input offset current 3. Input bias current 4. Output offset voltage 5. Slew rate 6. Common mode rejection An amplifier which provides a phase shift of 180 between input and output is called as Inverting Amplifier An amplifier which amplifies the input without producing any phase shift between input and output is called as Non-inverting amplifier. If the operational amplifier circuit output follows the input and hence it is referred to as Voltage follower. In Op-Amp Differentiator circuit output voltage is proportional to the first derivative of the input voltage. An op-amp circuit in which the output voltage waveform is the Integral of the input voltage waveform is termed as Integrator or Integration amplifier. Applications: Operational amplifier is used in the circuits like Adder, Sub tractor, Integrator, Differtiator, voltage follower and regulators. Points to be remembered: Characteristics of an ideal operational Amplifiers, Input and output offset voltage, Slew rate, Common mode rejection ratio and Construction Inverting and Non inverting amplifier circuits. UNIT - 7: COMMUNICATION SYSTEMS Introduction: The term communication, when used in its technical sense, refers to the sending, receiving and processing of information by electric means. Communication is defined as the process of transmitting information from one point, called the source, to another point called the destination. The source gives out information bearing signals called Messages. Messages are generally nonelectrical in nature. For example, voice, music picture etc. these are continuous signals and are called Analog messages. Generally original messages are converted to electrical form by an input device called the Transducer. The output form the transducer in the electrical form called a signal.

11 At the transmitter the used transducer may be Microphone, similarly, at the destination to convert output transducer eg: a loud Speaker. There are three essential blocks in a communication system called Transmitter, Transmission Channel and Receiver. Transmitter: The output of the transducer is a complex signal. It is restricted to desired rage of frequencies. Then an important operation called Modulation is performed. The process of modulation is required to match the transmitted signal to the transmission medium or channel. Receiver: The process of recovering the information signal from the received signal is called Detection or Demodulation. A device which performs this function is called a demodulator. After extracting the information signal, it has to be amplified and then fed to the output transducer. Modulation is the process of varying any one of the characteristics of a high frequency carrier wave in accordance with the instantaneous amplitude of modulating signal. Amplitude Modulation: When the amplitude of the carrier wave is varied in accordance with instantaneous amplitude of the modulating signal. It is termed as Amplitude modulation. Keeping frequency and phase of the carrier constant. Frequency Modulation: If the frequency of the carrier wave is varied in accordance with amplitude of modulating signal, keeping amplitude and phase of the carrier constant is called frequency modulation. Applications: Modulation and Demodulation process is applied in communication systems. Points to be remembered: Definitions of Modulation, Amplitude modulation, Frequency modulation. Block diagram of communication Transmitter and Receiver. Block diagram of Superhetrodyne receiver. UNIT 8: NUMBER SYSTEMS & DIGITAL LOGIC Introduction: The systems in which the output voltage/current has only states, either low or high are called binary digital systems. In computing systems, the binary symbols 0 and 1 are used to represent the two possible states of a digital circuit. Digital circuits include gates, flip-flops, multi-vibrators etc and digital systems include computers, calculators etc. Decimal number system consists of 10 symbols (0 to 9) each symbol has a positional value as well as an absolute value. Binary number system has a radix 2. As such, only two symbols (0 and 1) are allowed. Each binary digits in known as bit. A number in the binary system is written as a string of 1 s and 0 s.

12 Hexadecimal number system is another important number system widely used in microprocessors and computers. The radix in this system is 16 and as such there are 16 basic symbols 0 through 9 and A through F. also by using 4 bits, it is possible to represent all the basic hexadecimal numbers. It is possible to code each decimal digit using binary digits. This is called the Binary coded Decimal or BCD representation. George Boolean developed an algebra known Boolean algebra to evaluate the truth or falsity of a set of propositions either singly or joined to gather by the basic logical connections. Boolean algebra uses three basic operations: AND function, (similar to multiplication) OR function (similar to addition) and NOT function (similar to complementation) OR, AND and NOT gates are called Basic gates. NAND and NOR gates are called Universal gates. The logic circuits used to realize the Boolean expressions are known as Combinational circuits. Sequential circuit is one, the output is not only a function of present input, but also is a function of the past events. These circuits are incorporated in most digital systems as counters, sequence generators etc. Examples for combinational circuits are adders, sub tractors etc. Applications: Digital circuits are used in the construction of Shift Registers, Counter, Multivibrators and Digital systems like Calculators and Computers. Points to be remembered: Construction of Basic gates, Universal gates and design of half and full adders using universal, logic and basic gates.

PESIT BANGALORE SOUTH CAMPUS BASIC ELECTRONICS

PESIT BANGALORE SOUTH CAMPUS BASIC ELECTRONICS PESIT BANGALORE SOUTH CAMPUS QUESTION BANK BASIC ELECTRONICS Sub Code: 17ELN15 / 17ELN25 IA Marks: 20 Hrs/ Week: 04 Exam Marks: 80 Total Hours: 50 Exam Hours: 03 Name of Faculty: Mr. Udoshi Basavaraj Module