[4063] 67

T.E. (E & TC/Electronics, Indl. Elex.) Semester II Examination, 2011POWER ELECTRONICS

(2003 Course)

Time : 3 Hours Max. Marks : 100

Instructions : i) Solve Q. 1 or Q. 2, Q. 3 or Q. 4 and Q. 5 or Q. 6 fromSection I. Solve Q. 7 or Q. 8, Q. 9 or Q. 10 and Q. 11 orQ. 12 from Section II.

ii) Answers to the two Sections should be written in separate books.iii) Neat diagrams must be drawn wherever necessary.iv) Black figures to the right indicate full marks.v) Use of logarithmic tables and non programmable electronic

pocket calculator is allowed.vi) Assume suitable data, if necessary.

SECTION I

1. a) Explain the operating principle of SCR using two transistor analogy. 8

b) Draw and explain the driver circuit for IGBT. 8

OR

2. a) Explain the turn off mechanism of GTO. 8

b) What are the advantages of IGBT over power MOSFET and power BJT ? 4

c) Draw and explain reverse recovery characteristics of power diode. 4

3. a) With the help of a neat circuit diagram and relevant waveforms, explain the twoquadrant operation of single phase fully controlled bridge converter. Derive the

expression for average output voltage. 12

b) Define input supply power factor. Compare the input supply power factor of

semi converter and full converter. 4

OR

4. a) With the help of a neat circuit diagram and relevant waveforms, explain theoperation of three phase half controlled bridge converter. 12

b) Derive the expression for average output voltage of three phase fully controlledbridge converter. 4

P.T.O.

5. a) With the help of a neat circuit diagram and relevant waveforms, explain the

operation of three phase inverter operating with 180 degree conduction mode. 12

b) What do you understand by PWM ? Explain its advantages. 6

OR

6. a) Explain the operation of single phase square wave inverter with circuit diagram

and relevant waveforms. 10

b) Explain cross conduction or shoot through fault in inverter. How will you

overcome it ? Draw circuit diagram and necessary waveforms. 8

SECTION II

7. a) Write a short note on step up chopper. 6

b) What are resonant converters ? Explain the necessity of resonant converters.

What are their advantages ? 4

c) With the help of circuit diagram and waveforms explain the operation of SLR

half bridge DC/DC converter in low frequency (discontinuous conduction) mode. 8

OR

8. a) State and explain various control strategies used in dc-dc converters. 6

b) A step down DC chopper has a resistive load of R=15 and input voltageVs=200V. When the chopper is on, its voltage drop is 2.5V. The chopper

frequency is 1 KHz.

If the duty cycle is 50%, determine

i) Average output voltage

ii) rms output voltage

iii) Chopper efficiency 6

c) With the help of a neat circuit diagram and waveforms, explain the operation of

two quadrant type C chopper. Mention its application. 6

[4063] 67 -2-

9. a) Explain the operation of a single phase AC controller operating with integral

cycle control. 8

b) With the help of a circuit diagram, explain the use of TCA 785 for the control of

single phase AC controller. 8

OR

10. a) Draw the circuit diagram of 3 phase full wave AC controller. Explain its operation

with the help of relevant waveforms. The load is star connected balanced resistive

load. 10

b) Compare back to back connected SCR module and triac with reference to AC

controller. 6

11. a) Write short note on High frequency induction heating. 8

b) Explain various speed control techniques of a separately excited DC motor.

Compare them. 8

OR

12. a) Explain the advantages of HVDC transmission over HVAC transmission. Also

explain the 12 pulse converter used in HVDC transmission. 10

b) Write a short note on UPS. 6

-3- [4063] 67

B/II/11/970

[4063] 66

T.E. (E & TC/Electronics, Indl. Elex.) Semester II Examination, 2011ADVANCED MICROPROCESSORS

(2003 Course)

Time : 3 Hours Max. Marks : 100

Instructions : 1) Answer Question 1 or 2, 3 or 4, and 5 or 6 fromSection I and Question 7 or 8, 9 or 10 and 11 or 12from Section II.

2) Answers to the two Sections should be written inseparate answer books.

3) Neat diagrams must be drawn wherever necessary.4) Figures to the right indicate full marks.5) Assume suitable data if necessary.

SECTION I

1. a) Explain following addressing modes of 8086 with suitable examples. 8

i) Register Relative ii) Indexed

iii) Based indexed iv) Relative based indexed

b) Describe interrupt structure of 8086. 4

c) Write a program in assembly language of 8086 to reverse the string acceptedfrom user. 4

OR

2. a) Explain string related instructions in 8086. 6

b) Explain segmentation with reference to 8086 and its advantages. 6

c) Write a program in assembly language of 8086 to check whether the stringaccepted from user is palindrome or not. 4

3. a) Explain register model of 80386. 8

b) Explain different mechanisms of changing privilege levels of 80386. 6

c) State important features of VM86 mode in 80386. 4

OR

P.T.O.

4. a) Describe TSS and its role in multitasking. 6

b) With reference to 80386 explain important features of following modes : 8

i) Real Mode ii) Protected Mode

c) Draw and explain flag register of 80386. 4

5. a) Explain with suitable diagram memory organization in personal computer. 8

b) Explain various data encoding formats used for storing data on magneticdisk. 6

c) Write pins of PS/2 mouse. 2

OR

6. a) With suitable diagram explain interfacing of Keyboard to PC. 6

b) Explain with block diagram functioning of typical Pentium Motherboard. 6

c) Write two features of following video Adaptors 4

i) VGA ii) CGA

SECTION II

7. a) State advantages of USB over conventional serial bus. 4

b) With respect to USB explain 8

i) Endpoint ii) Enumeration

iii) Different types of data transfer

c) List specifications of ISA bus. 4

OR

8. a) Describe different signals associated with parallel port while interfacing 8 bit

ADC to PC 6

b) State important specifications of PCI bus. 4

c) Write a program in assembly language or in C to implement serial communication

between two PCs. 6

[4063] 66 -2-

9. a) What is device driver ? Explain structure of MS-DOS device driver. 8

b) What is preemptive and Non preemptive scheduling ? Explain and differentiate

between them. 8

OR

10. a) What is Inter process communication [IPC] ? What are different ways to achieve

mutual exclusion during IPC ? Explain any two of them. 8

b) With respect to file system explain 4

i) File Attribute ii) File Structure

c) What is TSR and what is its utility ? 4

11. a) Differentiate between RISC and CISC architecture. 6

b) Explain data flow model of ARM core. 8

c) What is AMBA ? Explain. 4

OR

12. a) Explain following modes of operation with reference ARM architecture. 6

i) Supervisory Mode ii) IRQ Mode

b) Draw and explain CPSR register. 4

c) Explain following ARM instructions : 8

i) LDR R0, [R1], # 4

ii) BL Next

iii) MOV R2, R #, LSL # 2

iv) Add R1, R2, R3.

-3- [4063] 66

B/II/11/1030

P.T.O.

[4063] 26

T.E. (Mechanical S/W) (Semester II) Examination, 2011THEORY OF MACHINES AND MACHINES DESIGN II

(2003 Course)

Time : 4 Hours Total Marks : 100

Instructions : 1) Answer 3 questions from Section I and 3 questions fromSection II.

2) Answers to the two Sections should be written in separatebooks.

3) Neat diagrams must be drawn wherever necessary.4) Use of logarithmic tables, slide rule, Mollier charts,

electronic pocket calculator and steam tables is allowed.5) Assume suitable data, if necessary.

SECTION I

1. a) Explain function generation, path generation and body guidance. 6

b) A four bar mechanism is to be designed, using three precision points, togenerte the function y = x1.5, for the range 4x1 .Assuming 30 starting position and 120 finishing position for the input linkand 90 starting position and 180 finishing position for the output link, findthe values of x, y, and corresponding to the three precision points. 10

OR

2. a) Derive an expression for displacement, velocity and acceleration of a followerhaving simple harmonic motion. 6

b) The following data relate to a cam operating an oscillating roller follower :

Minimum radius of cam = 30 mm

Radius of roller = 15 mm

Length of follower arm = 45 mm

Distance of fulcrum centre from cam centre = 60 mm

[4063] 26 -2-

Angle of ascent = 80

Angle of descent = 110

Angle of dwell between ascent and descent = 60

Angle of oscillation of follower = 30

Draw the profile of the cam if the follower moves outward with uniform

acceleration and retardation and returns with uniform velocity. 10

3. a) Derive the equation for maximum efficiency of spiral gears with a neat sketch. 8

b) Two gears having 30 and 40 involute teeth respectively are in mesh. The

pressure angle is equal to 20, module is 12 mm. Line of contact on each side

of the pitch point is two third of maximum possible length. Find the height of

addendum for each wheel, total length of path of contact and the contact

ratio. 8

OR

4. a) Write a short note on interference and undercutting. 6