## Basic Electrical and Electronic Engineering - Dec 2012

### First Year Engineering (Semester 2)

TOTAL MARKS:

TOTAL TIME: HOURS

**1** Define RMS value.(2 marks)
**10** State the functions of a satellite transponder.(2 marks)

### Answer any one question from Q11 (a) & Q11 (b)

**11 (a) (i)** For the circuit shown below, find the current through each of the three resistors.
(10 marks)
**11 (a) (ii)** A coil of resistance 5.94? and inductance of 0.35 H is connected in series with a capacitance of 35 ?F across a 200 V, 50 Hz supply. Find the impedance (z) current and the phase difference between voltage and current (?)(6 marks)
**11 (b) (i)** With a neat diagram explain the construction and principle of operation of a moving iron attraction type instrument.(10 marks)
**11 (b) (ii)** Three inductive coils, each with a resistance of 15 ? and an inductance of 0.03 H are connected in star to a three phase 400 V, 50 Hz supply. Calculate the phase current, line current and power absorbed.(6 marks)

### Answer any one question from Q12 (a) & Q12 (b)

**12 (a) (i)** Derive the emf equation of a DC generator.(8 marks)
**12 (a) (ii)** A short-shunt eumulative compound DC generator supplies 7.5 kW at 230 V. The shunt field, series field and armature resistances are 100, 0.3 and 0.4 ohms respectively. Calculate the induced emf and the load resistance.(4 marks)
**12 (a) (iii** A 30 kW, 300 V, DC shunt generator has armature and field resistance of 0.05 ohm and 100 ohm respectively. Calculate the total power developed by the armature when it delivers full output power.(4 marks)
**12 (b) (i)** A single phase 2200/250 V, 50 Hz transformer has a net core area of 36 cm^{2} and maximum flux density of 6 Wb/m^{2}. Calculate the number of primary and secondary turns.(4 marks)
**12 (b) (ii)** With the help of neat sketches, explain the construction and operating principle of split-phase induction motors.(12 marks)

### Answer any one question from Q13 (a) & Q13 (b)

**13 (a) (i)** With the help of V-I characteristics describe the working principle of zener diode. What is its symbol? Mention also the special properties of zener diode when compared to ordinary diode.(8 marks)
**13 (a) (ii)** What is the half-wave rectifier? Sketch its circuit. Discuss the operation of half-wave rectifier with help of necessary waveforms.(8 marks)
**13 (b) (i)** Explain in brief the input and output characteristics of CE configuration of a NPN transistor.(10 marks)
**13 (b) (ii)** Compare the performance of a transistor in three different configurations.(6 marks)

### Answer any one question from Q14 (a) & Q14 (b)

**14 (a) (i)** Simplify the following Boolean expressions:

(1) xy+x'z+yz

(2) (A'+B'+C'')?(A+B+C)?(C+D)?(C+D+E)(8 marks)
**14 (a) (ii)** Explain the working of JK flip flop with its logic diagram.(8 marks)
**14 (b) (i)** Draw the logic diagram of a 4-bit binary ripple counter and explain its working.(8 marks)
**14 (b) (ii)** Explain with the neat sketch the working of Binary Ladder Network for Digital to Analog conversion,(8 marks)

### Answer any one question from Q15 (a) & Q15 (b)

**15 (a) (i)** Explain frequency modulation. Obtain the mathematical representation of frequency modulated wave.(8 marks)
**15 (a) (ii)** What is meant by aplitude modulation? Explain also the connected terms 'Modulation Index', 'AM Wave Equation' and 'Spectrum'.(8 marks)
**15 (b) (i)** With the help of block diagrams describe the working of

(i) a typical TV transmitter(8 marks)
**15 (b) (ii)** a typical TV receiver.(8 marks)
**2** What are the advantages of electromechanical measuring instruments?(2 marks)
**3** What is back emf?(2 marks)
**4** Define: Transformation ratio of a transformer.(2 marks)
**5** What is meant by zener effect?(2 marks)
**6** Sate what is 'Early Effect' in transisters.(2 marks)
**7** Write the truth table of an Exclusive-OR gate.(2 marks)
**8** Mention two types of D/A converters.(2 marks)
**9** State any two differences between analog and digital signals.(2 marks)