Government Polytechnic 2010 Diploma in Hospital Management Elements of Power Electronics - Question Paper

Q.1 (a) Compare general purpose diode, fast recovery diode and schottky diode 07
(b) List the name of power semiconductor devices. provide the Power Electronics
converters classification with their applications
07
Q.2
(a) discuss construction and draw the V-I characteristics of UJT & DIAC. 07
(b) discuss 2 transistor analogy of SCR and discuss why silicon material
used in thyristor. describe the term latching & holding current.
07
OR
(b) discuss 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 discuss it's
working
07
(b) Draw R. C. Phase shift network and derive formula 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. discuss any 1 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 ? provide the advantages
of an RCT over a conventional thyristor.
07
OR
Q. four (a) discuss the switching characteristics of an IGBT. 07
(b) Compare power MOSFETs with power BJTs. 07
Q.5
(a) discuss 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
discuss working.
07
OR
Q.5 (a) describe function of snubber circuit. Draw snubber circuit for SCR and
Transistor.
07
(b) Draw circuit diagram for fixed AC to variable AC conversion and
discuss working.
07

Earning:   Approval pending.