1. Sample Question Paper - I
Course Name : Electronics and Telecommunication
Course Code : EJ/EN
9123
Semester : Fifth
Subject : Industrial Electronics.
Marks : 80 Time: 3 Hrs.
Instructions:
1. All questions are compulsory.
2. Illustrate your answers with neat sketches wherever necessary.
3. Figures to the right indicate full marks.
4. Assume suitable data if necessary.
5. Preferably, write the answers in sequential order.
Q.1. Attempt any Four of the following. 4 x 4 = 16
a. Draw the symbols of the following devices:
1. SCR 2. Diac 3. SBS 4. IGBT.
b. Describe the V/I characteristics of UJT with neat sketch.
c. Define commutation and mention all methods of commutation.
d. Draw the circuit diagram of three phase half wave delta-wye rectifier.
e. What is the function of free-wheeling diode in controlled rectifier?
f. Draw the structure of GTO and UJT.
Q.2. Attempt any Two of the following. 6 x 2 = 12
a. Describe single phase half wave controlled rectifier with resistive load with waveform
and circuit diagram.
b. Describe RC full wave triggering circuit with necessary schematic and waveform.
c. Describe three phase Delta-Wye Bridge Rectifier with waveform and circuit diagram.
Q.3. Attempt any Two of the following. 6 x 2 = 12
a. Describe six-phase half wave star connected rectifier with waveform and circuit diagram.
b. Describe single-phase half wave controlled rectifier with inductive load. Sketch its
waveform and circuit diagram.
c. What is the necessity of commutation? Explain Class C commutation with waveform.
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2. Q.4. Attempt any Two of the following. 8 x 2 = 16
a. Compare SCR and TRIAC, based on construction, symbol, properties and ratings.
b. Describe SCR triggering circuit using UJT with neat sketch. Also state the advantages of
pulse triggering methods.
c. The automation industry “Prime Control Pvt Ltd” wants to control single phase 1HP
motar using Full controlled rectifier. Describe its working with circuit diagram.
Q.5. Attempt any Two of the following. 6 x 2 = 12
a. Describe single phase full wave controlled rectifier with inductive load. Draw the circuit
diagram and waveform.
b. Draw V-I characteristic of Power Transistor and describe its regions.
c. Draw V-I characteristic of SCR and label it.
Q.6. Attempt any Two of the following. 6 x 2 = 12
a. Describe single phase controlled bridge rectifier with inductive load. Draw circuit
diagram and waveform.
b. Describe the construction of TRIAC with neat sketch.
c. List the different turn on methods of SCR. Describe dv/dt triggering method.
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