Downloaded From Code: 9A02403 B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 GENERATION OF ELECTRIC POWER Answer any FIVE questions 1 Discuss the advantages and disadvantages of a nuclear plant as c mpa ed to other conventional power plants. 2 Explain about: (a) Solar distillation. (b) Solar cooling. (c) Solar drying. 3 Draw the line diagram of a thermal power station showing various parts. 4 Describe the main consideration in selecting a site for wind generation. 5 Explain the constructional detail and working of KVIC digester. 6 (a) What are the main hurdles in the development of tidal power plants? (b) Explain how the waves are formed. 7 The load on the main supply system is 1000 kw at p.f. of 0.8 lagging. What must be the kva rating of the phase advancing plant which takes leading current at a power factor 0.15 in order to raise the power factor of whole system to 1.0? 8 What do you understand by tariff? Discuss the objectives of tariff.
Downloaded From Code: 9A02404 B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 ELECTROMAGNETIC FIELDS World Answer any FIVE questions 1 (a) State and explain Gauss s law. (b) Four concentrated charges Q 1 = 0.3 µc, Q 2 = 0.2 µc, Q 3 = 0.3 µc, Q 4 = 0.2 µc a e located at the vertices of a plane rectangle. The length of rectangle is 5 cm and b eadth f the ectangle is 2 cm. Find the magnitude and direction of resultant force on Q1. 2 What is electric field intensity? Explain the concept of electric field and write wn expression for the electric field due to point charge. 3 (a) Derive the expression for capacitance of the spherical condenser. (b) Find the current in the circular wire, if the current density is J =(1-e -100r )a z A/m 2. The radius of the wire is 2 mm. 4 (a) Determine the magnetic field intensity on the axis of an infinite solenoid. (b) A current carrying circular wire of radius a is centered on the origin in the plane z = 0. Obtain an expression for magnetic field intensity on the axis of the wire at (0, 0, 2). 5 (a) Explain the rotational vector operator. Give a physical example. (b) Three infinite conductors are carrying a current of 1, 2, 3 Amp respectively in same direction. The conductors are arranged in a straight line at a distance of 1 m. The conductor carrying current 1 A is left most and that 3 Amp is right most. Find the H at a point 1 meter exactly above the conductor carrying 1 Amp current. 6 (a) Explain magnetic dipoles and magnetic moment. (b) A rectangu ar coil of area 10 cm 2 carrying a current of 50 A lies on plane 2x + 6y - 3z = 7 such that the magnetic moment of the coil is directed away from the origin. Calculate its magnetic moment. 7 two-conductor transmission line is made up of conductors, which are separated by a distance of 2 meters. The radius of each conductor is 1 cm. The medium is air. Compute the exact value of inductance of each conductor per km length. Derive the formula used. All 8 Write Maxwell s equations in good conductors for time varying fields and static fields both in differential and integral form.
Downloaded From Code: 9A02405 B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 ANALOG ELECTRONIC CIRCUITS Answer any FIVE questions 1 Design of an emitter follower for maximum efficiency. The emitter follower has V CC = -V EE = 5 V, R 1 = 2.15 kω, and V CE (sat) = 0.2 V. Find the optimum value of RL for maximum efficiency and find the value of this efficiency. 2 Derive the voltage gain, input admittance and input miller capacitance f CS amplifier using its high frequency equivalent circuit. 3 (a) What are series and parallel mixing and voltage, current sensing in feedback amplifiers? (b) An amplifier has a voltage gain of 200, before negative feedback is applied. When negative feedback with β = 0.25 is applied, the nominal gain changes by 10%. Find the percentage change in the overall gain. 4 (a) Draw the JNTURCoscillator.singhybridequivalent model, justify the statement that the sustained oscillations is obtained by having the gain of transistor amplifier greater than 29. (b) Find the capacitor C and h fe for the transistor to provide a resonating frequency of 10 khz of a transistorized phase shift oscillator. Assume R 1 = 25 kω, R 2 = 60 kω, R C = 40 kω, R = 7.1 kω and h ie = 1.8 kω. 5 (a) Explain about power amplifiers and its features. (b) Derive an expression for efficiency of class-a amplifier. 6 (a) The periodic ramp voltage shown below is applied to a low pass RC circuit. Find the equations from which determine the steady state output waveform. (b) If T 1 = T 2 = RC, find the maximum and minimum value of the output voltage and plot this waveform. 7 With the help of neat wave forms explain the storage and transition times of diode. 8 Explain the method of unsymmetrical triggering of the binary with relevant circuit diagram.
Downloaded From Code: 9A02406 B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 NETWORK THEORY In the circuit shown below, If the switch K is closedworldatt=0,findtheexpressionforthe Answer any FIVE questions 1 (a) Explain the measurement of power in a 3-phase system. (b) Three inductive coils, each with a resistance of 10 Ω and an inductance of 0.05 H are connected in delta to three phase 400 V, 50 Hz supply. Calculate: (i) Phase current and line current. (ii) Total power absorbed. 2 3 4 A 3-phase, 3 wire supply of 440 V, RYB system has a star c nnected ad with Z R = 5 30 0, Z Y = 10 45 0 and Z B = 10 60 0 ohms. Calculate line currents and neutral displacement voltage. A series R-L circuit has R = 25 Ω and L = 5H. A dc voltage of 100 V is applied at t = 0. Find: (a) The equations for charging current, voltage across R and L. (b) The current in the circuit 0.5 sec later. JNTU1Ω (c) The time at which the drop across R and L are same. current i(t). 5 6 The Z- parameters of a two-port are Z 11 = 10Ω, Z 22 = 20Ω, Z 12 = Z 21 = 5Ω (a) Find the ABCD parameters. (b) Find the equivalent -network. Find h parameters of the two port network shown below: 1H 1H 1F 7 Derive the Fourier series of a triangular wave. 8 (a) State Parseval s theorem. (b) The voltage across a 10Ω resistor is v(t) = 5e 3t 4(t). Find the total energy dissipated in the resistor.
Code: 9A02407 Downloaded From B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 ELECTRICAL MACHINES - II World marks 1 (a) Compare between core type and shell type transformers. (b) Derive the emf equation of a 1-phase transformer and calculate the emf / turn, if the f ux is 0.015 Wb at a frequency of 50 Hz. 2 (a) Develop the equivalent circuit of a single-phase transformer. (b) A 200 kva, 1- phase, 3300 / 400 V transformer gave the f ll wing esults in the short circuit test with 200 V applied to the primary and secondary sh rt circuited, the primary current was full load value and the input power was 1650. Calculate the secondary potential difference and the % of regulation when the full l ad current was passing at a 0.707 p. f. lagging with normal primary voltage. 3 (a) Explain the O.C. and S.C. tests on the transformer and hence explain the evaluation of equivalent circuit from it. (b) Explain the operation of autotransformer with neat diagram. 4 (a) With neat phasor diagram, explain the voltage regulation of three-phase AnsweranyFIVEquestions transformer. (b) An ideal 3-phase step down transformer connected in delta/star delivers power to a balanced 3-phase load of 120 kva at 0.8 pf. The input line voltage is 11 kv and the turn's ratio of transformer (phase to phase) is 10. Determine the line voltage line currents, phase voltages, phase currents on both primary & secondary sides. 5 Describe briefly the working principle of slip ring induction motor. Explain how its speed control is effected? All 6 (a) A 4 pole, 400 V, 3-IM has a standstill rotor EMF of 100 V per phase. The rotor has resistance of 50 m/ph and standstill reactance of 0.5 /ph. Calculate the maximum torque & slip at which it occurs. Neglect stator impedance. (b) Exp ain the various losses taking place in IM. Explain the effect of slip on the performance of IM. 7 (a) Exp ain the procedure to calculate starting current in an induction motor and its dependence on rotor slip. (b) 10 pole, 3-phase, 50 Hz induction motor draws 2.5 A and 100 KW under the block rotor test. Find the starting torque when switched on direct to rated voltage and frequency supply. Assume the stator and rotor copper losses to be equal under the blocked rotor test. 8 (a) Explain about the speed control of induction motor by cascade operation. (b) Two 50 Hz 3-Ф induction motor having 6 & 4 poles respectively are cumulatively cascaded. The 6 pole motor being connected to the main supply. Determine frequencies of rotor currents and the slips referred to each stator field. If the set has slip of 2%.
Downloaded From Code: 9A04401 B.Tech II Year II Semester () Supplementary Examinations December/January 2014/2015 SWITCHING THEORY & LOGIC DESIGN (Common to EEE, ECE, EIE, E.Con.E & ECC) Answer any FIVE questions 1 (a) Explain the ASCII code with table. (b) Encode the following text in to 7-bit ASCII code: JNTU ANANTAPUR 2 (a) Prove that OR-AND network is equivalent to NOR-NOR netw rk. (b) Simplify the following Boolean functions to minimum number f literals: (i) x + y + xyz (ii) (x + xyz ) + (x + xyz )(x + x y z) (c) Realize XOR gate using minimum number of NAND gates. 3 (a) What are the advantages of Tabulation method over K -map? (b) Simplify the following Boolean function using Tabulation method: Y(A,B,C,D) = (1,3,5,8,9,11,15) 4 (a) Design 4-bit even parity generator. Mention truth table. (b) Design BCD to XS3 code converter using a 4 bit Full- adders MSI circuit. 5 (a) Find the minimal threshold-logic realization for the function: f(a,b,c,d) = Σm(2, 3, 6, 7, 10, 12, 14, 15) (b) Compare programmable logic devices. 6 With a neat sketch explain 4-bit Johnson counter 7 Find the equivalence partition and the corresponding reduce machine in standard form. PS NS 1 Z X = 0 X = 1 A D,0 H,1 B F,1 C,1 C D,0 F,1 D C,0 E,1 E C,1 D,1 F D,1 D,1 G D,1 C,1 H B,1 A,1 8 (a) Draw the ASM chart for binary divider. (b) Draw the state diagram for a full adder circuit and convert it to ASM chart.