written 6.5 years ago by |
Basic Electrical and Electronic Engineering - May 2012
AU First Year Engineering (Semester 2)
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary
1 State Kirchhoff's voltage and current law. 2 marks
2 State the different types of instruments based on their operating principles. 2 marks
3 What is the purpose of yoke in a dc machine? 2 marks
4 What are the types of transformers based on construction? 2 marks
5 Write the difference between the PN junction diode and zener diode. 2 marks
6 Give the biasing conditions for a transistor to operate as an amplifier. 2 marks
7 What are Universal Gates? Why do we call them so? 2 marks
8 What is a shift register? How is it classified? 2 marks
9 State the basic characteristics of an analog signal, with an example. 2 marks
10 Give typical values of uplink frequency and downlink frequency in satelite communication. 2 marks
Answer any one question from Q11 (a) & Q11 (b)
11 (a) (i) Use mesh analysis to determine the three mesh currents in the circuit shown below.10marks
11 (a) (ii) A series R-C circuit R=20 ? and C=127 ?F has 160 V, 50 Hz supply connected to it. Find the impedance, current and power factor. 6 marks
11 (b) (i) For the circuit shown below, calculate the line current, the power and the power factor. The value of R, L and C in each phase are 10?, 1 H and 100 ?F respectively
8 marks
11 (b) (ii) Explain the principle of operation of attraction type and replusion type of moving iron instruments with neat sketches. 8 marks
Answer any one question from Q12 (a) & Q12 (b)
12 (a) (i) Draw the circuit diagram of the following three types if dc motors and write the relationships among the current and voltages:(1) Separately excited motor.
(2) Series motor
(3) Shunt motor 6 marks
12 (a) (ii) Explain the characteristics of a dc, shunt motor. Sketch the graphical representation of the concerned characteristics. 2 marks
12 (a) (iii A DC motor connected to a 460 V supply has an armature resistance of 0.15 ohms. Calculate
(1) the value of back emf when the armature current is 120 A
(2) the value of armature current when the back emf is 447 V
6 marks
12 (b) (i) Explain the construction and working principle of capacitor start and capacitor run single phase induction motor. What are its advantages and practical applications? 8 marks
12 (b) (ii) Explain the principle of operation of single phase transformer. 8 marks
Answer any one question from Q13 (a) & Q13 (b)
13 (a) (i) Explain the mechanism of avalanche breakdown and Zener breakdown. 8 marks13 (a) (ii) With the help of relevant circuit and V-I characteristics, show how a zener diode is used as a voltage regulator. 8 marks
13 (b) (i) Explain the operation of PNP transistor. 6 marks
13 (b) (ii) With neat sketch explain the input and output characteristics of a transistor in CB configuration. Draw also the necessary circuit. 10 marks
Answer any one question from Q14 (a) & Q14 (b)
14 (a) (i) Explain the working of clocked master slave JK flip flop with logic diagram. 8 marks14 (a) (ii) Show that NAND and NOR gates are universal building blocks. 8 marks
14 (b) (i) Explain Successive-Approximation A/D conversion. 8 marks
14 (b) (ii) Explain the operation of Asynchronous conunter. 8 marks
Answer any one question from Q15 (a) & Q15 (b)
15 (a) (i) What is meant by modulation and demodulation? 4 marks15 (a) (ii) Explain briefly the principle of modulating a carrier signal by amplitude modulation and also obtain the expression for power. 12 marks
15 (b) (i) With a neat block diagram, explain the principle of operation of microwave communication. 8 marks
15 (b) (ii) Draw the block diagram of optical fibre communication system and explain the function of each block. 8 marks