JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II ELECTRICAL AND ELECTRONICS ENGINEERING Previous Question Paper (November/December - 2018 - R13)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks.
Main
State Kirchhoff’s laws.
Answer
Kirchhoff’s Current Law (KCL): The algebraic sum of currents meeting at any junction in an electrical circuit is zero. Kirchhoff’s Voltage Law (KVL): The algebraic sum of the products of currents and resistances in any closed loop of a network plus the algebraic sum of the electromotive forces (EMFs) in that loop is zero.
State Ohm’s law and write its applications.
Answer
Ohm’s Law: At constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends.
State the function of commutator in D.C. Generator.
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Give the classification of D.C. Motors.
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What is the main purpose of using core in a transformer?
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Why transformer efficiency is high compared to other general electrical devices?
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Explain diode forward current.
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Draw the circuit symbol for a PNP and NPN transistors.
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What is meant by delay line in CRO?
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Explain about vertical amplifier in CRO.
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Explain the star to delta transformation with a simple example.
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Discuss briefly the essential features of indicating instruments.
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Two batteries A and B with the internal resistances RA and RB are connected in parallel to supply current of 150A to a load resistance RL. Given EA = 120V, RA = 0.15 ohms and RB = 0.1 ohms and IB = 60A. Calculate EB and power drawn by the load.
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Describe the constructional details and working of a moving iron repulsion type meter.
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Explain the operation of 3-point starter in a DC machine.
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A 6-pole generator has a lap-wound armature with 40 slots with 20 conductors per slot. The flux per pole is 25 mWb. Calculate the speed at which the machine must be driven to generate an e.m.f. of 300 V.
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Derive the torque equation of a DC motor.
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Calculate the generated e.m.f of a 4-pole, wave-wound armature having 38 slots with 18 conductors per slot when driven at 1000 rpm. The flux / pole is 0.018 wb.
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Draw and explain about the torque slip characteristics of an induction motor.
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A 10-pole, 3-phase induction motor runs at a speed of 485 rpm at 50 Hz supply. Determine: i) synchronous speed ii) slip.
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Explain the principle and operation of a transformer. Also list different types of transformers.
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A 3-phase, 2-pole 50 Hz induction motor has a slip of 4% at no-load and 6% at full load. Find: i) Synchronous speed, ii) Full-load speed, iii) No-load speed and iv) Frequency of rotor current at stand still.
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Explain the operation of a half wave rectifier with the help of circuit diagram.
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Draw and explain the input and output characteristics for transistor CE configuration?
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Explain about the principle of operation of PNP transistor. Discuss how it is operated as an amplifier?
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Explain the time base generator of a CRO, with a neat diagram.
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What is the minimum distance that will allow full deflection of 5cm at the CRT screen with a deflection factor of 100V/cm and with an acceleration potential of 2050V?
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Explain how lissajous figures can be used in frequency measurement?
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Draw the block schematic of a CRO and explain its operation.
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