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QUESTION BANK
CODE / SUBJECT
: ME 2255-ELECTRONICS & MICRPROCESSOR
NAME OF THE STAFF
: N.NAGARAJ
UNIT I
SEMICONDUCTORS AND RECTIFIERS
Classification of solids based on energy band theory-Intrinsic semiconductorsExtrinsic semiconductors-P type and N type-PN junction-Zener effect- Zener diode
characteristics-Half wave and full wave rectifiers -Voltage regulation
PART A
1. What are valence electrons? (May’10)
2. What are conductors and insulators? Give examples? (May’10)
3. Define breakdown voltage in PN junction. (May’09)
4. What are Intrinsic and extrinsic semiconductors? (May’09, May’07)
5. What is rectifier? Which main electronic device is involved in rectification?(May’08)
6. What is the energy gap? (May’08)
7. Define electro static deflection sensitivity. (Nov’08)
8. Define voltage regulation. (Nov’08)
9. Draw the energy band diagram for an insulating material. (May’07)
10. Define Zener breakdown voltage. (Nov’07)
11. Draw the energy band diagram for Ge and Si. (Nov’07)
12. What is meant by Doping? Give an Example. (May’06)
13. Differentiate intrinsic and extrinsic semiconductors with examples. (May’06)
14. Define the terms: Drift and Diffusion. (Nov’06)
15. Determine the current flowing through the Zener diode for the circuit Shown, if
Rr =5K, Input Voltage is 50 V, R = 2 k and output voltage is 30 V. (Nov’06)
16. Explain with reference to energy band theory the difference between conductors,
Isolators and semiconductors. (Nov’06)
PART B
1. Explain N-type and P-type semiconductor with their energy band diagram? (May’10)
2. Explain the following: a. Mobility b. Drift current c. Conductivity d. Diffusion current.
(May’10)
3. What is a PN junction? What happens when PN junction is, 1) Forward biased 2)
Reverse biased. (May’09, Nov’08, May’03)
4. Explain the terms: i) Zener effect ii) Barrier potential. (May’09)
5. How Zener diode acts as voltage regulator? (May’09)
6. Explain the working of full wave rectifier with filter and draw the input and output
Waveforms. Derive the formula for the average output voltage. (May’09, May’08,
Nov’07&May’07, May’03)
7. A charged particle having charge thrice that of an electron and mass twice that of an
electron is accelerated through a potential difference of 50 V,before it enters a uniform
magnetic field of flux density of 0.02 Wb/m2 at an angle of 2b0 with the field. Find i)the
velocity of the charged particle before entering ii)Radius of the belical path and iii) time
of one revolution.(Nov’08)
8. Differentiate the avalanche and zener breakdowns. (Nov’08)
9. Derive the ripple factor and efficiency of a half wave rectifier. (Nov’08& Nov’07)
10. What is ‘Barrier potential’ in a PN junction? What happens to the PN junction, when
it is forward biased and reverse biased? Draw the appropriate diagram. (May’08)
11. Explain the phenomena involved in the breakdown of a PN junction under reverse
Biased condition. (May’08)
12. Briefly explain the following: i) Intrinsic semiconductors
ii) Extrinsic semiconductors. (Nov’07)
13. Compare the V–I characteristics of a Zener Diode to that of a Tunnel diode. (Nov’07)
14. Illustrate with a neat sketch the functioning of a voltage regulator.
15. Make a detailed classification of solids based on energy band theory. (May’07)
16. Compare in detail half wave and full wave rectifiers. (May’07)
17. How are intrinsic and extrinsic semiconductors different? (May’07)
18. Draw and explain a typical V-I characteristics of a semiconductor diode. (May’06)
19. Find the conductivity and resistivity of an intrinsic semiconductor at temperature of
300K .It is given that: Intrinsic concentration (n) =2.5 x1013/cm3, Electron mobility
(μ C)=3800 cm2/V, Hole mobility (μ h) =1800 cm2/V, Electron charge (q) =1.6x10-19 C.
(May’06)
20. Draw the V-I characteristics of a zener diode and explain Zener breakdown
Phenomena. (Dec’06)
21. Explain how ion charges produce internal barrier voltage Vb in a PN junction by
showing its depletion zone. (Dec’06)
22. Write short notes on the applications of semiconductor diodes. (Dec’06)
UNIT II
TRANSISTORS AND AMPLIFIERS
Bipolar junction transistor- CB, CE, CC configuration and characteristics-Biasing
circuits-Class A, B and C amplifiers- Field effect transistor-Configuration and
characteristic of FET amplifier-SCR, Diac, Triac, UJT-Characteristics and simple
applications-Switching transistors-Concept of feedback-Negative feedbackApplication in temperature and motor speed control.
PART A
1. Why FET is called voltage controlled device? (May’10)
2. Why do we choose q point at the center of the load line? (May’10)
3. What are the types of biasing circuits? (May’09,Nov’07)
4. Mention any two applications of SCR. (May’09)
5. What is thermal runaway in transistors? (Nov’08)
6. Define intrinsic stand-off ratio in UJT. (Nov’08)
7. Why transistor is called a current controlled device. (May’08)
8. What is a feedback amplifier? (May’08)
9. Write any two applications of UJT. (Nov’07)
10. Draw the fixed bias circuit for a BJT. (May’07)
11. Write two advantages of negative feedback .(May’07,Dec’06)
12. What are the three configuration of a transistor amplifier? (May’07)
13. Draw a neat diagram of a single SCR based half wave rectifier circuit and draw
the voltage characteristics. (May’07)
14. Explain a biasing circuit for BJT. (May’07)
15. What are the different types of field effect transistors? (May’06)
16. What are the important parameters for the performance of an amplifier? (Dec’06)
17. Define: Break over voltage. (Dec’06)
18. Define the current gain of a transistor amplifier. (May’03)
19. Explain the terms: (a) Firing angle and (b) Conduction angle of an SCR.(May’03)
PART B
1. Describe the working principle of single stage common emitter (CE) amplifier.
Sketch the output characteristics .Indicate the active, saturation and cut-off regions.
(May’09, May’08, Nov’07, May’06 & May’03)
2. Explain the construction, operation, volt ampere characteristics, and application of
SCR, also explain its two transistor model and state any two applications.
(May’10, May’09)
3. Derive the general expression for stability factor. (May’09)
4. Explain the working of SCR and state any two applications. 4. Explain the concept of
feedback. (May’09)
5. State any two applications of switching transistors in motor speed control. (May’09)
6. Why TRIAC is called a double ended SCR? Explain the construction, operation and
Characteristics of a Triac with a help of neat diagram. (May’08)
7. With a neat diagram explain the construction, operation, characteristics and
Applications of SCR. (Nov’08, Nov’07)
8. Write in detail about the working of N-channel J-FET along with its construction and
Characteristics. (Nov’08, Nov’07)
9. Compare four different biasing circuits in detail. (May’07)
10. Discuss how negative feedback improves stability, increases bandwidth and reduces
Distortion. (May’07)
11. Discuss the application of TRIAC in temperature control. (May’07)
12. Explain the basic principle and operation of UJT and list its applications. (Nov’07)
13. In a transistor collector current is 0.98mA and base current is 20μA.Determine the
Values of, i) Emitter current ii) Current amplification factor iii) Current gain. (May’06)
14. Explain the three methods of triggering (switching ON) an SCR by gate control.
(May’06)
15. An a.c. voltage of v=200
sin 100∏t is applied to a SCR. If the SCR has a
Forward breakdown voltage of 200 V.Determine the period of conduction. (May’06)
16. Explain the input-output characteristics for common base NPN transistors with its
Neat graphs. (Nov’06)
17. Explain the class of operation for amplifiers in terms of output current IO, with neat
Sketches. (Nov’06)
18. Explain the methods of turning ‘ON’ and turning ‘OFF’ the SCR. (Nov’06)
19. Describe the common –source amplifier circuit with N-channel depletion type of FET.
(Nov’06)
20. Compare JFET with BJT. (May’03)
UNIT-III
DIGITAL ELECTRONICS
Binary number system - AND, OR, NOT, NAND, NOR circuits-Boolean
algebra-Exclusive OR gate - Flip flops-Half and full adders-RegistersCounters-A/D and D/A conversion.
PART A
1. Convert 0.640625 decimal numbers to its octal equivalent. (May’10)
2. What is meant by bit and byte?
3. Write the binary equivalent of 25,355.(May’09)
4. What are flip flops? .(May’09, May’08)
5. Draw the circuit of full adder.(Nov’08)
6. What are the key factors to be considered in the selection of ADC/DAC? (Nov’08)
7. Solve the following: (1F8)16 = (?)8= (?)2. (May’08)
8. What are the different types of flip flops? (Nov’07,Nov’06)
9. Convert the binary number 110001 in to its decimal equivalent. (Nov’07)
10. Write the truth table for AND, OR, NOR and XOR gates. (Nov’07)
11. Write four laws of Boolean algebra. (May’07)
12. Write the truth table for 2- input NAND gate.(May’07)
13. State De Morgan’s theorem. (May’06)
14. Draw the 2-input AND gate and give its truth table. (May’06)
15. What are binary counters? (Nov’06)
16. Draw the circuit of a 4 bit ripple counter. (May’03)
17. Convert the following hexadecimal numbers to decimal.(May’03)
(a) 4 AB, (b) 23 F
PART B
1. Explain the working of JK, RS flip flops. (May’10,May’09)
2. Explain counters. (May’10)
3. Write the truth table for AND, OR, NOT, NAND, NOR, XOR. (May’09)
4. Explain the working of successive approximation type A/D converter.
(May’09,Dec’06,May’03)
5. Design a full adder.(May’09,Nov’07,May’07)
6. Reduce the following equation using tabular method and implement the result.
F= ∑ m (0, 2, 3, 5, 8, 10, 11, 13)
(Nov’08)
6. With the support of logic and timing diagram, explain the operation of a 0 bit
Synchronous binary counter. (Nov’08)
7. Which gates are called universal gates? Why? State and prove De Morgan’s
Theorem with truth table. (May’08)
8. List the types of A/D converter and explain any one with suitable diagram. (May’08)
9. Draw the logic diagram, symbol and truth table of a full adder and explain its
Operation. (May’08)
10. Draw a circuit diagram of clocked R-S flip flop and explain its function with truth
Table. (May’08)
11. Design the following digital circuit: Half adder. (Nov’07, May’07)
12. Reduce the given expression: (Nov’07)
i) Y= (A+B+C) (A+B)
ii) Y= AB+ABC+ABC
iii) Y=1+A (BC+BC+BC) +ABC+AC
iv) Y= (A+B+C) + (B+C)
13. Explain the working of the following: (Nov’07)
i) JK flip flop
ii) T-flip flop
14. Discuss the advantage of binary systems. (May’07)
15. Describe the operation of 4 bit, binary ripple counter. (May’07)
16. Write short notes on A/D conversion. (May’07)
17. Explain the functional operation of D-type edge triggered flip flop by giving its
Logical diagram and truth table. (May’06)
18. Convert the decimal number 129 to a BCD (Binary coded decimal). (May’06)
19. Write the Boolean expression for the following combinational logic
Circuit. (May’06)
20. Explain the functional operation of a binary ripple counter with its logical
Diagram. (May’06)
21. Construct a logic diagram from the simplified Boolean expression and give its
Truth table. (Dec’06)
AB +BC = AB +BC=X
22. Define flip flops. Draw the constructional figure for reset/set type, flip flop and
Explain its stable states with active LOW and active HIGH inputs. (Dec’06)
23. Justify why the NAND gate is considered as a universal logic gates. (Dec’06)
UNIT IV
8085 MICROPROCESSOR
Block diagram of microcomputer-Architecture of 8085-Pin configurationInstruction set-Addressing modes-Simple programs using arithmetic and
logical operations.
PART A
1. Steps involved to fetch a byte in 8085. (May’10)
2. What is the use of ALE? (May’10)
3. List the various types of addressing modes in 8085. (May’09)
4. Explain the following instructions: i) LHLD ii) SHLD. (May’09)
5. Describe shortly on DAA instruction. (Nov’08)
6. What is a mnemonic instruction? (May’08)
7. What is meant by addressing mode? (May’08)
8. What are the various types of addressing modes in 8085?
(Nov’07,May’07,May’03)
9. Explain the following instructions in 8085: i) SHLD ii) STAX rp. (Nov’07)
10. Write a program using INTEL 8085 instructions, to add two 8–bit numbers and
store the result in the memory. (Nov’07)
11. Distinguish the instructions DAA and DADH of Intel 8085. (Nov’07)
12. List four interrupts of 8085. (May’07)
13. Write different external hardware synchronization instructions of 8085. (Nov’06)
14. Give the description for the instruction ‘RRC’ of 8085. (Nov’06)
15. What are the four operations that are performed primarily by the micro processing
unit (MPU)? (May’06)
16. How are branch instructions classified? (May’06)
17. What is tri state logic? Why it is needed in microprocessor system? (May’03)
18. What is meant by synchronous and asynchronous data transfer? (May’03)
PART B
1. Compare CALL and PUSH instructions. (May’10)
2. How does the microprocessor differentiate between data and instruction?
(May’10)
3 Describe the architecture of INTEL 8085. (May’09, May’03, Nov’08, May’08,
Nov’07, May’07,)
4. What are various types of addressing modes? Explain in detail with example.
(May’09, May’08, May’03)
5. Write a simple program in 8085 to perform addition of two decimal numbers.
(May’09)
6. Write in detail about the 8085 interrupts with a neat sketch. Also write about the
instructions supporting the interrupts. (Nov’08)
7. Write a program using INTEL 8085 instructions, to add two 8–bit numbers and
store the result in the memory. (May’08, Nov’07, Dec’06)
8. Explain the operation of the following 8085 program. (May’08)
LXI SP, 07FFH
PUSH B
PUSH H
POP B
POP H
HLT
9. Discuss in detail the instruction set of 8085 with example. (May’07, May’06,
Dec’06, May’03)
10. Write an assembly language program to find the biggest and smallest in an array
of given numbers. (May’07)
11. Explain the classification of instruction set (Three groups) according to word
size, by giving example instructions to each group with their labels.(May’06)
UNIT V
INTERFACING AND APPLICATIONS OF MICROPROCESSOR
Basic interfacing concepts - Interfacing of Input and Output devices-Applications of
Microprocessor Temperature control, Stepper motor control, traffic light control.
PART A
1. What is a Buffer and explain tri state buffer. (May’10)
2. If an information flows to memory, which signal is used by it? (May’10)
3. List out the basic interfacing concepts. (May’09)
4. Mention the microprocessor which is used in traffic light controllers. .(May’09)
5. Draw the circuit that is used to drive relay coil or solenoid.(Nov’08)
6. What are the memory mapping techniques available in 8085? (Nov’08)
7. Differentiate absolute and incremental encoders. (Nov’08)
8. What is memory -mapped I/O port? (May’08)
9. Discuss the role of microprocessor in traffic light control. (May’08)
10. Compare I/O mapped I/O and memory mapped I/O of 8085. (Nov’07)
11. Explain the range of control lines while interfacing a memory to an 8085 processor.
12. Write any two applications of the microprocessor 8085. (Nov’07,Nov’06)
13. List the ports of 8085. (May’07)
14. Write the control word format of 8255 PPI. (May’07)
15. What is key de bounce on microprocessor? (May’06)
16. Compare memory mapped I/O and peripheral I/O. (May’06)
17. Differentiate polling and interrupt. (Nov’06)
18. Compare static and dynamic RAM. (May’03)
PART B
1. Draw the circuit and waveform for a four phase stepper motor interface and explain
its operation with the sequence table. (May,10,Nov’08, Nov’07)
2. Explain I/O interfacing. (May’10)
3. Explain about the basic interfacing concepts. (May’09)
4. Explain the application of microprocessor in temperature control.
(May’09,May’08)
5. Explain the application of microprocessor as a traffic light controller using suitable
diagrams, flow chart and assembly language program. (May’09,May’07)
6. Illustrate with a neat sketch the interface of a matrix keyboard to
Intel 8085 processor. Also write a program to enter key data into memory. (Nov’07)
7. Design an interface circuit that compares the present room temperature with the set
temperature and switches on/off the cooler relay coil based on the result of
comparison by using 8-bit microprocessor. (Nov’08)
8. Show a interface circuit of 8 bit input port with switches and 8 bit output port with
LED’s to a 8085 microprocessor. (May’08)
9. Explain about the interfacing input output devices in 8085 by the technique I/O
mapped I/O. (Nov’07)
10. Discuss in detail the process of data transfer between the 8085 microprocessor and
peripherals with detailed description. (May’06,Dec’06)
11. Discuss in detail about any one of the applications of microprocessor (8085) based
control technique. (Dec’06)