R.B.V.R.R. WOMEN S COLLEGE (AUTONOMOUS) Narayanaguda, Hyderabad. ELECTRONIC PRINCIPLES AND APPLICATIONS

Size: px

Start display at page:

Download "R.B.V.R.R. WOMEN S COLLEGE (AUTONOMOUS) Narayanaguda, Hyderabad. ELECTRONIC PRINCIPLES AND APPLICATIONS"

Hubert Baker
5 years ago
Views:

1 R.B.V.R.R. WOMEN S COLLEGE (AUTONOMOUS) Narayanaguda, Hyderabad. DEPARTMENT OF PHYSICS QUESTION BANK FOR SEMESTER V PHYSICS PAPER VI (A) ELECTRONIC PRINCIPLES AND APPLICATIONS UNIT I: SEMICONDUCTOR DEVICES FUNDAMENTALS OF TRANSISTORS UNIT II: OPERATIONAL AMPLIFIER MICRO PROCESSOR UNIT III: MODULATION AND DETECTION COMMUNICATION SYSTEM UNIT IV: COMBINATIONAL L OGIC CIRCUITS SEQUENTIAL LOGIC CIRCUITS H.O.D.

2 UNIT I SEMICONDUCTOR DEVICES Long answer questions for five marks: 1. What is zener diode? Draw a circuit to study the zener diode characteristics? 2. Describe working of zener diode. Explain how it used for voltage regulation? Mention its applications? 3. Describe the construction and working of a tunnel diode. Sketch its V-I characteristics and indicate the negative resistance portion? 4. What is a Clipper? Describe i) positive clipper ii) biased clipper and iii) combination clipper. 5. What is a varactor diode? Explain its action. 6. Draw V-I characteristics of tunnel diode and sketch a) tunneling current b) injection current and c) total current as a function of applied voltage. 7. Describe working of schottky diode? Explain its V-I characteristics. 2

3 I FUNDAMENTALS OF TRANSISTORS Long answer questions for five marks: 1. Draw the common emitter transistor characteristics and explain the transistor action? 2. Differentiate between NPN and PNP transistors? Draw a circuit diagram for drawing the static characteristics of a common emitter transistor? 3. Explain the working of a transistor and define its and parameters establish the relation between = 1 / (1- ). 4. Give high frequency hybrid pi model of CE configuration of a transistor and discuss its various parameters. 5. Discuss input and output characteristics of CE configuration. Hence explain cutoff, active and saturation regions? 6. Discuss the output and transfer characteristics of a JFET. Explain one application of JFET? 7. Explain with a neat circuit diagram, an experiment to determine the output and transfer characteristics of a FET? 8. What is meant by enhancement mode and depletion mode of operation of MOSFET? Give the symbols of MOSFETS? 9. Describe the structure of a silicon controlled rectifier. Draw its V - I characteristics? 10. Give the basic structure of SCR and study the V -I graph for SCR and how it uses as a power control device? 11. What is SCR? Give its symbol and two transistor representation. Mention few applications. 12. Draw the circuit diagram of single stage R-C coupled amplifier and explain its frequency response curve? 13. What is meant by feed back? Define negative and positive feedback and explain advantages of negative feedback? 3

4 SEMICONDUCTOR DEVICES Short answer questions for two marks: 1. What is zener diode? Draw its equivalent circuit? 2. What is varicap diode? Explain its action. 3. Draw tunnel diode characteristics and explain. 4. Explain the working of schottky diode? 5. Explain zener and avalanche break downs? 6. How is zener diode acts as voltage regulator? I FUNDAMENTALS OF TRANSISTORS Short questions each question carrying two marks: 1. Write a note on h parameters of a transistor. 2. Discuss the advantages of FET and MOSFET over BJT? 3. State two differences between JEFT and MOSFET? 4. Give working mechanism of a FET. Sketch the depletion region before and after pinch off? 5. Define a Pinch off voltage of a JFET. 6. Draw a circuit of RC coupled CE configuration amplifier and discuss its response at low, mid and high frequency response. 7. Explain the concept of feedback and their classification? 8. What is feed back? Define negative and positive feedback in an amplifier. 9. Discuss the effect of negative feedback. 10. Write down the advantages and disadvantages of negative feedbacks. 4

5 CHAPTER - I SEMICONDUCTOR DEVICES Problems for 2 marks: 1. Varactor diode has a capacitance of 20 PF when a reverse bias voltage of 4 volts is applied across it. Find the diode capacitance when reverse bias voltage is increased to 9 volts? 2. A zener diode has a break down voltage of 9.1 volts with a maximum power dissipation of 364 milli watts. What is the maximum current the diode can handle? I FUNDAMENTALS OF TRANSISTORS: Problems for 2 marks: 1. In a transistor circuit collector load is 4 K. Whereas quiescent current (zero signal collector current) is 1 ma. i) What is operating point if VCC = 10 V? ii) What is operating point if RC = 5 K. 2. A change of 200 mv in base emitter voltage cause a change of 100 A in the base current. Find the input resistance of the transistor. 3. In a transistor, if IC = 49 ma and Ig = 5 ma. What is the value of? 4. When a reverse gate voltage of 15 V is applied to a FET, the gate current is 10-3 A. Find the resistance between gate and source. 5. For the transistor = 150, VCC = 9 V and RC = 1 k. Operating point is fixed at IC = 3 ma. Find the value of RB and VCE. 6. In a negative feedback amplifier, the gain without feedback is 100, feedback ratio is 1/25 and input voltage is 50 mv. Calculate gain with feedback. 7. An amplifier has a voltage gain of 50. If the gain is reduced to 10 by negative feedback, then determine the percentage of feedback. 5

6 8. An amplifier having input impedance 1 k and gain 1000 is subjected to negative feedback. What will be its input impedance if feedback ratio is 0.01? 9. An amplifier voltage gain is 50. If the gain is reduced to 10 by negative feedback. Determine the percentage of input which is feedback. 10. The negative feedback reduces the voltage gain of an amplifier from 500 to 100 calculate negative feedback ratio. 11. An amp has a voltage gain 100 without feedback. A fraction of its output voltage is applied to input in such a way that the gain reduces to 50. Find feedback factor. 12. An amplifier has a gain of 200 without feedback if 1/600 of the output voltage is applied to the input. Then calculate the voltage gain when the feedback is negative. 6

7 UNIT II OPERATIONAL AMPLIFIER Long answer questions for five marks: 1. Obtain an expression for gain of an OP-Amplifier connected in an inverting mode? 2. Describe the working of an inverting OP-Amp and derive the expression for output voltage and gain? 3. Describe the working of a non-inverting OP-Amp and derive the expressions for output voltage and gain? 4. Draw the block diagram of an IC op-amp and explain its different stages and explain characteristics of an ideal op-amp? 5. What is an op-amp? Explain briefly the following i) Slewrate ii) power band width iii) CMRR. 6. Explain the terms 1) Virtual group 2) Bias current 3) input and output off set voltage. 7. With the help of a neat circuit diagram explain how op-amp is used to generate a sine-wave? 8. With the help of a neat circuit diagram explain how op-amp is used to generate a square wave? 7

8 CHAPTER - II MICRO PROCESSOR Long answer questions for five marks: 1. What is Microprocessor? Give the detail construction of Intel 8085? 2. Give a block diagram of Intel What are its main sectors? 3. Mention the different arithmetic and logic operation performed by ALU? 4. What are the different ways of specifying the data in the instruction? Give examples? 5. What do you mean by assembly language? What are mnemonics. 6. Draw a schematic diagram of the pin configuration of Intel 8085A and describe the role of different parts? 7. Explain briefly data transfer and arithmetic logic instruction of 8085 microprocessor? 8. Explain the following instruction of 8085 microprocessor? I) MOV, II) MVI, III) LXI, IV) LDA, V) LHLD, VI) STA VII) SHLD, VIII) AOC, IX) ADD, X) SUB with an example. 9. What is the register? Explain the various registers of 8085 and also the role of RAM and ROM? 10. What do you mean by opcode and operands? Explain the following one-word instructions. I) MOV A, B II) ADD B and what do you mean by two word and three word instruction. Give example. 8

9 OPERATIONAL AMPLIFIER Short questions each question carrying two marks: 1. What is an operational amplifier? 2. Give the block diagram of an operational amplifier? 3. What is a differential amplifier? 4. What do you mean by CMRR? 5. Draw the schematic symbol of an operational amplifier indicating the various symbols? CHAPTER - II MICRO PROCESSOR Short questions each question carrying two marks: 1. What is a microprocessor? Draw the pin configuration of Intel Give a block diagram of Intel 8085 with its main parts? 3. Explain the following instruction of 8085 microprocessor: a)add b) JMP. 4. What do you mean by assembly language? 9

10 OPERATIONAL AMPLIFIER Problems for 2 marks: 1. An op-amp has a CMRR value of 60 db. Find the differential mode gain if the common mode gain is Calculate the CMRR of an op-amp having differential voltage gain of 1200 and common mode gain of If an op-amp has an output signal of 10 volts with a slew rate of 2 V/ s, then calculate the power band width in amplifier? 4. An op-amp has differential gain of 100 and common mode gain of 0.1. Estimate common mode rejection ratio. 5. Determine the maximum operating frequency of an op-amp which has a slew rate equal to 0.5 V/ s and a maximum peak output voltage VPK of approximately V. 6. An op-amp has a gain width product of 1.5 MHz Find the operating band width for the following closed loop gains. I) AV = 1 ii) AV = 10 iii) AV = In an IC differential amplifier the CMRR is 55 db and Ad is What is Ac? 10

11 UNIT III MODULATION AND DETECTION Long answer questions for five marks: 1. Mention different types of antennas. Obtain an expression for antenna gain? 2. Define amplitude modulation. Find an expression for an amplitude modulated wave with sinusoidal modulation. 3. Explain how FM is generated using i) varactor diode ii) Reactance tube modulator and iii) phase modulators? 4. Describe the need for modulation? Write about the working of an amplitude modulator? 5. Describe the theory of FM? Explain the working of FM radio receivers? 6. What are the advantages of FM over AM? Describe the working of simple frequency modulator. 7. Explain the radio detection of FM waves? 8. What is modulation and demodulation? Why modulation is necessary in communication system and what are essentials in demodulation? 9. Explain the general principle of radio broad casting, transmission and receiver? 10. What do you understand by side band frequencies in an A.M. wave? Give expression for the fraction of total power carried by the side bands in amplitude modulation. 11

12 CHAPTER - II COMMUNICATION SYSTEM Long answer questions for five marks: 1. What are the basic elements of a radio communication system? 2. What are the different types of radio transmitter? With a block diagram briefly explain an AM radio transmitter? 3. How electromagnetic waves are propagated from a transmitting to receiving antenna? Discuss briefly. 4. How radio receivers can be classified? What are its essential functions? Mention the important characteristics of broad cast receivers. 5. Explain briefly the following a) vertical aerial b) inverter L aerial c) T aerial and d) dipole aerial. 6. What is an antenna? Mention the important characteristics of an ideal receiving antenna. 7. Briefly discuss the operation of radar system? 8. With a suitable diagram explain briefly the plan of a television system? 9. Mention the different applications of radar. And deduce the range equation of radar? 10. Discuss briefly about receiving arrangement of a TV system? Give a block diagram? 11. What is mean by TV scanning? Mention fundamentals of picture analysis. 12

13 MODULATION AND DETECTION Short answer questions for two marks: 1. What are modulations? Classify their different types and explain? 2. Why modulation is necessary in communication system? 3. Explain amplitude modulation. 4. What do you understand by frequency modulation? Explain its advantages over amplitude modulation. 5. What do you understand by modulation factor? What is its significance? CHAPTER - II COMMUNICATION SYSTEM Short answer questions for two marks: 1. What is the basic element of a radio communication system? 2. What is an antenna? Mention different types of antennas. 3. Explain the following a) vertical aerial 2) Inverted α aerial 3) T- Aerial and 4) Dipole aerial. 4. Briefly discuss the operation of a radar system? 5. Mention the different application of a radar? 6. Write a note on television? 13

14 MODULATION AND DETECTION Problems for two marks: 1. A 100 watt carrier is modulated to a depth of 50%, calculate the total power in the modulating wave? 2. What is the modulation index in which the modulating frequency is 12 KHz and maximum deviation is 10 KHz? 3. The power of an AM signal is 400 W. If the modulation index is 1 find the power of carrier? 4. The carrier swing of an FM wave is 150 KHz, calculate the modulation index for a signal of frequency 10 KHz? 5. Calculate the percentage modulation of a signal is FM broadcast and at 72 MHz with 36 KHz frequency deviation? 6. A broadcast radio transmitter radiates 100 Kw when the modulation percentage is 60. How much of this is carrier power. 7. A sinusoidal carrier voltage of amplitude 0 V and frequency 1 MHz is amplitude modulated by a sinusoidal voltage of frequency 10 KHz producing 40% modulation? Determine frequency and amplitude of lower and upper side band. 8. In an amplitude modulated wave it is found that V max = 0.8 and V min = 0.2. Estimate modulation index? 14

15 UNIT IV COMBINATIONAL LOGIC CIRCUITS Long answer questions for five marks: 1. Name the three Boolean operators. Write down the laws of Boolean algebra and discuss how a Boolean expression can be reduced? 2. State and prove De-Morgan theorems. What is meant by demorganization? 3. What is half adder? Give the symbol for half adder and its truth table? 4. What is full adder? Give its symbol. Give the truth table for a three input adder and discuss? 5. Explain the working of B-CD to decimal decoder. What is multiplexer? 6. What is an encoder? Give the block diagram of an encoder for generating an output code for every character of a key board and hence discuss its working. 7. Explain the working of decimal to BCD encoder in brief. 8. Construct 8-1 multiplexer. Explain it with neat diagram. 9. Construct 1-16 De-multiplexer. Explain it with neat diagram. 15

16 I SEQUENTIAL LOGIC CIRCUITS Long answer questions for five marks: 1. What are the uses of flip-flops? Explain its operation. Draw a flip-flop circuit with outputs? 2. Draw the circuit diagram of an RS flip flop using NOR gate? 3. Give the logic symbol for JK flip-flop and MS JK flip-flop and discuss? 4. What is Schmitt trigger? Discuss its operation and analyze the wave form obtained. 5. What is a shift register? Give the basic block diagram and discuss the wave form. 6. Explain the construction of decode counter with neat circuit diagram. 7. How decade counter is different from binary counter and draw a three cascade decade counter units and explain briefly how it works? 8. What is ROM? Show that a ROM may be considered as a decoder for the input code followed by an encoder for the output code. 9. What is RAM? Explain how RAM operates illustrate with a diagram. 10. What are synchronous and asynchronous counters? Illustrate with neat diagram. 16

17 COMBINATIONAL LOGIC CIRCUITS Short answer questions for two marks: 1. Name the three Boolean operators? 2. State De-Morgan s theorems. 3. Discuss how Boolean expression can be reduced. 4. Prove that AB + BC + CA = AB + CA. 5. Discuss Half adder and full adder, explain with its circuit diagram. 6. What is an encoder and decoder? I SEQUENTIAL LOGIC CIRCUITS Short answer questions for two marks: 1. What is a shift register? Give its basic block diagram. 2. What are the uses of flip-flop? Explain its operations? 3. Give the logic symbol for the R-S flip flop? 4. What is Schmitt trigger? Discuss its operation? 5. Write a short note on a) RAM b) ROM 17

18 COMBINATIONAL LOGIC CIRCUITS Problems for two marks: 1. A) Convert ( )10 in to binary b) Convert (100)10 in to binary. 2. Add binary numbers110, 111and Subtract (101101)8 from (110011)2 using 1 s complement method. Show direct subtraction for comparison. 4. Obtain 1 s and 2 s complement of and Simplify logic expression. 6. Prove this by Boolean algebra and Demorgan s theorem. 7. Design logic circuit representing Boolean expression. 8. Design the logic circuit using different logic gates.. 9. Design a logic circuit whose output is given by Boolean expression 18

Preface... iii. Chapter 1: Diodes and Circuits... 1

Preface... iii. Chapter 1: Diodes and Circuits... 1 Table of Contents Preface... iii Chapter 1: Diodes and Circuits... 1 1.1 Introduction... 1 1.2 Structure of an Atom... 2 1.3 Classification of Solid Materials on the Basis of Conductivity... 2 1.4 Atomic