BASIC ELECTRICAL AND ELECTRONICS ENGINEERING

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2007

Annual Pattern – First Year

Aeronautical Engineering

EE1X02 – BASIC ELECTRICAL AND ELECTRONICS ENGINEERING

(Common to Automobile Engineering/Marine Engineering/Mechanical Engineering/Production Engineering)

(Regulation 2004)

Time: Three hours                                                     Maximum: 100 Marks

Answer ALL questions.

PART A – [10 X 2 = 20 MARKS]

1. State Kirchoff’s voltage law with suitable electric circuit.

2. an alternating current of frequency 60Hz has a maximum value of 120A. Write down the equation for its instantaneous value.

3. what is the function of commutator in DC machine?

4. Why is the range of efficiency in Transformer higher than those of other electrical machines?

5. Which type of induction motor would you use for the following applications?

a. Wet grinders

b. Food processors and mixers

c. Ceiling fan

d. Lift and cranes

6. Name any two methods of starting of a synchronous motor.

7. How does a PN junction behave under forward and reverse biased condition?

8. Sketch the VI characteristics of a SCR and mark various regions of operations.

9. Why are AM systems preferred in broadcasting than FM systems?

10. What are function performed by the receiving modem?

PART B – [5 X 16 = 80 MARKS]

11. (a) (i) A filament lamp is rated for 100W, 110V. Find the value of the resistance to be connected in series with this lamp so that it can be operated on a 230V supply. What is the power loss in the resistor? [8 MARKS]

(ii) A voltage wave has the variations as explained. The graph is between V(t) and t(s). v(t) in y-axis and t(s) in x-axis. The voltage raises linearly w.r.t time till it reaches 6V in 3 seconds. At 3seconds it immediately raises to 8V and remains constant for a second. When t=4s the voltage falls down reaches 0 and raises linearly w.r.t. time in negative side as in the positive side. When t=7 V=-6 and when t=8 V=0. [8 MARKS]

[OR]

(b) (i) A coil of resistance 10Ω and inductance 0.1H is connected in series with a 150µF capacitor across 200V, 50Hz supply. Calculate impedance, current and power factor. [6 MARKS]

(ii) Explain with the help of a neat sketch, the principle of working of a single-phase induction type energy meter. [10 MARKS]


12. (a) (i) Draw the circuit diagram of any two types of DC generators. Sketch and explain the load characteristics of these generators. [10 MARKS]

(ii) What are the methods by which the speed of DC motor be controlled? Explain any one method applied to DC shunt motor. [6 MARKS]

OR

(b) (i) Develop an approximate equivalent circuit for a single phase two winding transformer. State the assumptions made. [8 MARKS]

(ii) A 220/440 V single phase transformer has the following test result:

OC Test: 220V, 1A, 70W on Low voltage side.

SC Test: 20V, 2A, 100W on High voltage side.

Obtain the equivalent circuit parameters of the transformer referred to LV side. [8 MARKS]



13. (a) (i) What are the different methods of starting 3-phase squirrel cage induction motor? Describe with a connection diagram, the working of any one starter. [8 MARKS]

(ii) Explain the operation of shaded pole induction motor with neat diagrams. What are the disadvantages of this motor? [8 MARKS]

OR

(b) (i) Starting from fundamentals, derive the emf equation of an Alternator. Discuss the effect of winding factor on the induced emf. [8 MARKS]

(ii) Write short notes on V curve of a Synchronous motor. [8 MARKS]


14. (a) (i) What is inductive transducer? Explain the working of LVDT in brief. [8 MARKS]

(ii) With suitable diagram explain the operation of n-type enhancement mode MOSFET. Also draw its transfer characteristics. [8 MARKS]

OR

(b) (i) Explain the working principle and operation of any one photoelectric device with neat sketch. Sketch the V-I characteristic also. [8 MARKS]

(ii) Draw the circuit of a full-wave bridge rectifier and explain its working principle. [8 MARKS]


15. (a) (i) Draw the block diagram of a communication system and explain its operation. [8 MARKS]

(ii) Discuss the principle of operation of Mobile phones. [8 MARKS]

OR

(b) (i) Draw the block diagram of optical fibre communication system and explain it. [8 MARKS]



(ii) With neat diagram, explain the conceptual view of ISDN connection feature. [8 MARKS]