1 (a)
What is the power electronics? Give two applications of P.E.

6 M

1 (b)
What is the difference between thyristor and a TRIAC?

4 M

1 (c)
What are the peripheral effects of power electronics equipments?

10 M

2 (a)
What is a bipolar transistor and explain how many types are there and what are their three region operations?

10 M

2 (b)
What are pinch of voltage, threshold voltage and transconductance of MOSFET?

6 M

2 (c)
Compare the BJT, MOSFET and IGBTs.

4 M

3 (a)
What is the difference between SCR and a TRIAC? Explain its characteristics?

8 M

3 (b)
Q3(b)and Q3(c)

Q3(b) The input voltage of Fig.Q3(b) is V

3(c) What is the common technique for voltage sharing and serial connected thyristor?

Q3(b) The input voltage of Fig.Q3(b) is V

_{s}=200V with load resistance of R=5?. The load and stray inductance are negligible and the thyristor is operated at frequency of f_{s}=2 kHz. If the required dv/dt is 100 V/?s and the discharge current is to be the limited to 100 A. Determine (i) the value of R_{s}and C_{s}(ii) the snubber loss and (iii) the power rating of snubber resistor.3(c) What is the common technique for voltage sharing and serial connected thyristor?

8 M

4 (a)
With a neat diagram and waveforms, explain the principle of single phase full connectors purely resistive load. Determine the expression for voltage o/p voltage and rms o/p voltage.

10 M

4 (b)
What are the advantages and disadvantages of series conveters?

6 M

4 (c)
How do you classify phase control converters? Explain.

4 M

5 (a)
Draw a circuit diagram and associated waveforms, explain the operation of a single phase bi-directional AC voltage controller with resistive load, obtain the rms output voltage.

10 M

5 (b)
An ac voltage controller in Fig.Q5(b) has a resistive load of R=10? and the root-mean-square (rms) input voltage is V

_{s}=120V, 60Hz. The thyristor switch is on for n=25 cycles and is off m=75 cycles. Determine (i) the rms output voltage V_{0}, (ii) the input power factor (PF) and (iii) the average and rms current of thyristors.
7 M

5 (c)
What are the advantages and disadvantages of ON-OFF control?

3 M

6 (a)
What is an inverter? Explain its principle of operation (any one) with a neat diagram and waveforms.

8 M

6 (b)
What are the performance parameter of inverters?

6 M

6 (c)
How to differentiate 1? and 3? inverters?

6 M

7 (a)
What is the principle of stepdown operation of chopper?

4 M

7 (b)
The stepdown chopper circuit shown in Fig.Q7(b)(i) & (ii), having resistive load. Derive an expression for the following:

(i) Average output voltage V

(ii) rms output voltage V

(i) Average output voltage V

_{0}(av)(ii) rms output voltage V

_{0}(rms).
8 M

7 (c)
A chopper circuit is operating on TRC at a frequency of 2 kHz on a 460 V supply of the load voltage of 350 V. Calculate the conduction period of the thyristor in each cycle.

8 M

Write short notes on:

8 (a)
Communication techniques

5 M

8 (b)
Difference between ON-OFF control and phase control

5 M

8 (c)
Static induction transistor (SIT's)

5 M

8 (d)
Performance parameters of rectifier.

5 M

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