Elements of Power Electronics Government Polytechnic 2010 Question Paper

Exam Board: Government Polytechnic
Question Paper Course: Diploma Hospital Management
Subject of Question Paper: Elements of Power Electronics
Time allotted: 3 Hours
Max. Marks: 70
Year of the exam paper: 2010
Question Paper Format: Text

Q.1 (a) Compare general purpose diode, fast recovery diode and schottky diode 07
(b) List the name of power semiconductor devices. Give the Power Electronics converters classification with their applications 07

Q.2 (a) Explain construction and draw the V-I characteristics of UJT & DIAC. 07
(b) Explain two transistor analogy of SCR and explain why silicon material used in thyristor. Define the term latching & holding current. 07
OR
(b) Explain briefly, what happens in a thyristor when the rate of rise of load current and rate of rise of anode to cathode voltage are excessive? 07

Q.3 (a) Draw UJT relaxation oscillator circuit with waveform and explain its working 07
(b) Draw R. C. Phase shift network and derive equation for it. 07
OR
Q.3 (a) Draw PUT Triggering circuit with waveform and write it's operation. 07
(b) List the turn-on methods of SCR. Explain any one with circuit diagram and waveform using pulse transformer. 07

Q.4 (a) What Is IGBT ? Sketch the equivalent circuit and transfer characteristics of an IGBT. 07
(b) How does GTO differ from a conventional thyristor ? Give the advantages of an RCT over a conventional thyristor. 07
OR
Q. 4 (a) Explain the switching characteristics of an IGBT. 07
(b) Compare power MOSFETs with power BJTs. 07

Q.5 (a) Explain the operation of a single – thyristor half wave controlled rectifier with waveform. 07
(b) Draw circuit diagram for fixed DC to variable DC conversion and explain working. 07
OR
Q.5 (a) Define function of snubber circuit. Draw snubber circuit for SCR and Transistor. 07
(b) Draw circuit diagram for fixed AC to variable AC conversion and explain working. 07

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