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RGPV First Year Engineering (Set B) (Semester 2)
Basic Electricals & Electronics Engg.
December 2011
Basic Electricals & Electronics Engg.
December 2011
Answer any one question from Q1 and Q2
1 (a)
What do you understand by dependent and independent source? Explain with neat sketches.
7 M
1 (b)
State superposition theorem. In the given network, marketing use of superposition theorem, determine the current in resistors R1, R2 and R3 and also the current in voltage source E.
7 M
2 (a)
Voltage v(t)v0cos (?r+?) is applied to a series circuit containing resistor R, inductor L and capacitor C. Obtain expression for the steady state current.
7 M
2 (b)
Describe star connecting method for interconnection of 3-phase supply.
7 M
Answer any one question from Q3 and Q4
3 (a)
i) State Faraday's Law of electromagnetism.
ii) What is meant by turn ratio in transformer?
iii) What is megneto-motive force?
iv) Mention the two important electrical performances of transformer.
ii) What is meant by turn ratio in transformer?
iii) What is megneto-motive force?
iv) Mention the two important electrical performances of transformer.
7 M
3 (b)
Explain the principle of operation of transformer with suitable sketches.
7 M
4 (a)
The O.C. and S.C. tests on 5kVA. 230/110 V. 50 Hz transformer gave the following data:
O.C. test (H.V. side) - 230 V, 0.6 A, 80W
S.C. test (L.V. side) - 6V, 15 A, 20W
Calculate percentage efficiency and regulation of a transformer on full load at 0.8 p.f. lagging.
O.C. test (H.V. side) - 230 V, 0.6 A, 80W
S.C. test (L.V. side) - 6V, 15 A, 20W
Calculate percentage efficiency and regulation of a transformer on full load at 0.8 p.f. lagging.
7 M
4 (b)
Derive the condition for maximum efficiency of a transformer.
7 M
Answer any one question from Q5 and Q6
5 (a)
Derive the expression for generated voltage in D.C. machine.
7 M
5 (b)
Draw and explain the construction of a single-phase induction motor with neat sketches.
7 M
6 (a)
Obtain an expression for e.m.f. equation of 3-phase induction motor.
7 M
6 (b)
What are the different methods of speed control in D.C. motor? Discuss in details.
7 M
Answer any one question from Q7 and Q8
7 (a)
Convert the following numbers into decimal:
i) (11111111)2
ii) (100)8
iii) (FFFF)16
iv) (01010101)2
v) (100-100)2
i) (11111111)2
ii) (100)8
iii) (FFFF)16
iv) (01010101)2
v) (100-100)2
7 M
7 (b)
Give the logic symbol ad truth table for the following logic gates (any two):
i) NAND
ii) NOR
iii) NOT
iv) EX-OR
i) NAND
ii) NOR
iii) NOT
iv) EX-OR
7 M
8 (a)
Distinguish between combinational and sequential logic circuits giving example of each.
7 M
8 (b)
Draw the circuit diagram of a half adder and derive its truth table.
7 M
9 (a) (i)
Name any three materials which are most widely used as semiconductor.
7 M
9 (a) (ii)
What type of semiconductor results when silion is doped with (a) donor impurities (b) acceptor impurities?
7 M
9 (a) (iii)
What is doping?
7 M
9 (a) (iv)
What is intrinsic semiconductor?
7 M
9 (a) (v)
What is operating points?
7 M
9 (b)
Explain the forward and reverse bias operating and voltage-current characteristics of a PN junction diode.
7 M
10 (a)
Explain the working of Bipolar junction transistor in common emitter configuration.
7 M
10 (b)
Explain how a BJT can be used as (i) An amplifier (ii) 2 switch
7 M
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