Download Answer any two questions - Sahrdaya College of Engineering and

COMBINED FIRST AND SECOND SEMESTER B. TECH
(ENGINEERING) EXAMINATION, APRIL 2014
SUBJECT :EN 09 107- BEEC
(2009 Scheme)
Time : 3 Hours
Maximum Marks : 70
SECTION 1 (Basics of Electrical Engineering) Maximum Marks : 35
Part A
Answer all questions
1. State KCL and KVL?
(2 marks)
2. What is meant by Reluctance
(1 mark)
3. What is the difference between dc series generator and dc shunt generator
(2 marks)
Part B
Answer any two questions
4. Explain the terms self inductance and mutual inductance
(5 marks)
5. Explain the principle of synchronous generator
(5 marks)
6. what are the difference between squirrel cage and slip ring induction motor
(5 marks)
(2 x 5= 10 marks)
Part C
Answer all questions
7. (a) (i) State and explain Faraday’s laws.
(ii) compare electric and magnetic circuit
(5 marks)
(5 marks)
Or
(b) (i) three coils each of resistance 5Ω and inductive reactance of 12 Ω are joined in star
across 400 V, 3-phase lines. Calculate the line current and power absorbed
(5 marks)
(ii) Derive the impedance, current and power factor for a series RLC circuit with phasor
diagram.
(5 marks)
8. (a)Explain the construction and working principle of a transformer with neat diagram(10
marks)
Or
(b) Explain the construction and working principle of a DC generator with neat diagram(10
marks)
(2 x 10= 20 marks)
SECTION 2 (Basics of Electronics and Communication Engineering)
Maximum Marks : 35
Part A
Answer all questions
1. Mention the advantages and disadvantages of negative feedback?
2. What is meant by logic ‘0’ and logic ‘1’?
(2 marks)
(1 mark)
3. What is meant by hand off
(2 marks)
Part B
Answer any two questions
4. Explain the concept of Operational amplifier
(5 marks)
5. Explain the principle of actuator
(5 marks)
6. Explain the principle of light transmission through fibre
(5 marks)
(2 x 5= 10 marks)
Part C
Answer all questions
7. (a) (i) Explain various types of noises in amplifier
(5 marks)
(ii) Explain the principle of Oscillator
(5 marks)
Or
(b) (i) Explain the principle of Digital to Analog Convertor
(ii) Write short note on TTL NAND Gate
(5 marks)
(5 marks)
8. (a)
Draw the block diagram of AM superheterodyne receiver and explain
(10 marks)
Or
(b) (i) Draw the block diagram of Pulse radar and explain
(ii) Write short note on GPRS technology
(5 marks)
(5 marks)
(2 x 10= 20 marks)
COMBINED FIRST AND SECOND SEMESTER B. TECH
(ENGINEERING) EXAMINATION, APRIL 2014
SUBJECT :EN 09 107- BEEC
(2009 Scheme)
Scheme of Evaluation
Time : 3 Hours
Maximum Marks : 70
SECTION 1 (Basics of Electrical Engineering) Maximum Marks : 35
Part A
Answer all questions
1. Each law carry 1 mark.
KCL - Algebraic sum of current meeting at a node is zero
KVL - Algebraic sum of voltages around a closed path is zero.
2. Reluctance (S)
- It is the opposition offered by the magnetic circuit to the establishment of magnetic flux.
S α l/a
= l/µ0µra
3. DC series generator – field winding is connected in series with the armature winding
DC shunt generator – field winding is connected in parallel with armature winding
Draw the diagrams for each
Part B
4. The property of a coil due to which it opposes any change of current or flux through it is called
self inductance. L= NФ/I . explain in detail
5. The rotor of the generator is driven by a prime-mover. At the same time a dc current is flowing in
the rotor winding which produces a rotating magnetic field within the machine. This rotating
magnetic field induces a three-phase voltage in the stator winding of the generator. Draw the
cross sectional view of the generator and explain in detail
6. (i) Squirrel-cage:
-Consists of a cylindrical laminated core with slots nearly parallel to the shaft axis or skewed.
-A thick copper or aluminum bar is placed on each slot.
-rotor bars conductors are shorted at both ends by heavy end rings.
-Simple, cheap & rugged construction
-Low starting torque
(ii) Slip ring rotor (wound rotor)
 Carries a three-phase windings and uniformly distributed in the slots.
 rotor windings are usually star connected, the ends of the three rotor wires are connected
to 3 slip rings on the rotor shaft.
 Brushes are used to take the connection from these slip ring to the variable resistors
 At starting, resistances are included and after attains normal speed resistances are cut off.
Part C
7. (a) (i) Faraday’s laws of electromagnetic induction
First law
Whenever the magnetic flux linked with a circuit changes, an emf is induced in it.
Or
whenever a conductor cuts the magnetic flux lines, an emf is induced in the conductor
Second law
The magnitude of the induced emf is directly propotional to the rate of change of flux linkages
(ii) write any five difference electric and magnetic circuit
or
(b) (i) draw the star connected circuit and marks given values – 1 mark
For finding the line current -3 marks
For finding power – 1 mark
(ii) series circuit diagram- 1 mark
Derivation of impedance-2 marks
Power factor - 1 mark
Current – 1 mark
8. (a) Diagram – 2 marks
Construction details – 4 marks
Principle of operation – 4 mark
or
(b) Diagram – 2 marks
Construction details – 4 marks
Principle of operation – 4 mark
SECTION 2
(Basics of Electronics and Communication Engineering)
Maximum Marks : 35
Part A
Answer all questions
1. Advatages - Stable gain
Increased bandwidth
Increased input impedence
Decreased output impedence
Reduced non linear distortion
Reduced noise
Disadvantages - It reduce gain
2. In digital Electronics 2 voltage levels or states are allowed. These states are referred as logic 1
and logic 0, high or low, true or false
Eg: Lamp ON – logic 1
Lamp OFF- logic 0
3. Hand off- Process of changing assignment of a mobile unit from one base station to another
as the mobile unit moves from one cell to another cell. Decision of hand off based on the signal
strength.
Part B
Answer any two questions
4.
Operational amplifier- Definition
Block Diagram and explanation
Equivalent circuit diagram and equation
Ideal Op- amp characteristics
Mention 9 parameters
5. Actuator - definition
Types of actuator- Light, Force, displacement, Motion, Sound and Heat actuator
6. Total internal reflection with diagram
Snells Law [n1sinθ= n2sinθ ] and explanation
Illustration of Light transmission through fiber
Numerical aperture NA=sinθa
Part C
Answer all questions
7. (a) (i)Noise –definition
Types of noise - Thermal noise
- Shot noise
- Microphonic noise
- Parasitic oscillations
- Hum
Signal to noise ratio
(ii) Oscillator- definition and principle
Barkhausen criteria
3 cases
Block diagram
(b) (i) Schematic diagram and explanation
Analog output equation
(ii) TTL NAND circuit diagram ,explanation
Truth table
8. (a) AM super heterodyne receiver block diagram and explanation
Standard intermediate frequency value of AM
Function of mixer circuit
(b) (i) Definition and Principle of RADAR
Block diagram of pulse RADAR and explanation
(ii) GPRS technology
Features of GPRS
GPRS services
GPRS applications