RTU 2016 Question Paper Semester I Old Electrical & Electronics Engineering

Total No ol Pages: I
1E1006
B. Tech I Sem. (Back) Exam. Jan.2016
10s (Old) Electrical & Electronics Engineering

Time: 3 Hours Maximum Marks: 80
Min. Passing Marks: 24
I ns tructi ons to C andidate s :
Attempt any five questions, selecting one questian from each unit. All questions
carry equal marks. Schematic diagrams must be shown wherever necessary. Any
data you feel missing suitably be assumed and stated clearly.
Units of quantities used/calculated must be stated clearly.
Use of following supporting material is permitted duing examination.
(Mentioned inform No. 205)
1. NIL 2. NIL

UNIT.I
Q.l (a) Find the equivalent resistance between the points A and B. t8l

[1E1006] Page 1 of4 [10001

(b) Find the current In in the circuit using mesh analysis. i8l

42;75Y

OR

Q.l (a) Determine the current I through 3C) resistor using Theremin's theorem t8l
2Y lo

10v t,oo I J

(b) Explain superposition theorem with an exampie. t8l

UNIT.II
Q.2 (a) Derive the expression for power for a series RC circuit in 1- I AC with phasor
diagram. t8l

(b) A coil of power factor 0.6 is in series with a 100pF capacitor. When connected to.
50Hz supply, the voltage across the capacitor is equal to voltage across the coil.
Find the resistance and inductance of the coil, t8l

[1E1006] Page 2 of 4 [10001

OR
Q.2 (a) Derive the relation between phase and line current for a three phase delta
connection. Also draw the neat phasor diagram. t8l
(b) Two wattmeters used to measure the power input in a 3-phase balanced circuit,
indicate 1000 watts and 800 watts respectively. Find the PF of the circuit - i8l
(, When both readings are positive
(ii) When the later is obtained by reversing the current coil connection

UNIT.III
Q.3 (a) Derive the EMF equation of a 1- rp transformer and define transformation ratio.
t8l
(b) The emf per turn of a 3300/395 V, 50H2, 1- g transformer is 7.5V. If the
maximum flux density is 1.0 tesla, find the suitable number of primary and
secondary tums and net cross sectional area of t}te core. t8]
OR
Q.3 (a) Explain the construction and working of a 1- <p transformer. t8l
(b) Two coils A and B having 1200 and 800 turns respectively are placed near each

other.6OVo of the flux of each coil is linked with the other coil. A current of 5A
in coil produces a flux of 0.25mWb while the same current in coil B produces a
flux of 0.15mWb. Find the mutual inductance and coefficient of coupling
between the two coils. t8l

UNIT.IV

Q.a (a) What is biasing of a PN junction? Draw and explain the volt-ampere
characteristics of a diode. t8l
(b) Explain intrinsic and extrinsic semiconductors with neat diagram. t8l

[181006] Page 3 of4 [1000]

OR

Q.4 (a) What is a rectifier? Discuss full wave rectifiers with proper diagram and
waveform. t8I

O) Explain various types of filters used after rcctification of AC signals. t8l

UNIT.V

Q.5 (a) With neat diagram, explain how the transistor works as an amplifier? t8l
(b) What is a transistor? Explain its construction and biasing. t8l

OR
Q.5 (a) Draw the corlmon emitter configuration and its inpuroutput characteristics. Also
explain various operating regions of a transistor. tl6l

[1E1006] Page 4 of 4 [1oo0l