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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
Fifth Semester B.Tech Degree Examination (Regular and Supplementary), December 2020

Course Code: EC307
Course Name: POWER ELECTRONICS & INSTRUMENTATION
Max. Marks: 100 Duration: 3 Hours
PART A
Answer any two full questions, each carries 15 marks. Marks

1 a) With neat sketch explain in detail the static and dynamic characteristics of power (7)

diode.
b) Compare VI characteristics of power BJT with conventional BJT. (4)
c) Howa GTO can be TURN ON and TURN OFF? (4)
2 a) Draw the structure of power MOSFET and explain its channel formation. (6)
b) Describe the working principle of buck converter with help of circuit diagram (9)
and relevant waveform. Write the expression of its output voltage and ripple
current.
3 a) Describe the working of forward converter with neat schematic. (5)
b) What is the advantage of power electronics over linear electronics? (2)
c) With neat circuit diagram and switching waveform explain the working of push (8)
pull converters.
PART B
Answer any two full questions, each carries 15 marks.
4 a) Explain Schering’s bridge with neat diagram and derive the balancing condition. (8)
b) With block diagram explain the working of online UPS. Mention ௩௦ (7)
applications.
5 a) Write short notes on SMPS. (4)
b) Distinguish static and dynamic characteristics of instrument. Define any 4 static (7)
characteristics.
c) List the various PWM switching schemes. (4)

6 a) With neat block diagram explain the functional elements of instrumentation (7)

system.