JNTU
JNTU B.Tech II ELECTRICAL AND ELECTRONICS ENGINEERING Previous Question Paper (March - 2022 - R13)
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Main
Classify Network elements and give their volt-ampere relations.
Answer
Network elements are broadly classified into two categories: Active and Passive elements.
Active Elements: These elements are capable of delivering energy to the network. They act as sources of energy. Examples include voltage sources and current sources.
Volt-Ampere relations:
Passive Elements: These elements are capable of receiving or storing energy but cannot generate it. Examples include resistors, inductors, and capacitors.
Volt-Ampere relations:
Elements can also be classified as Linear/Non-linear (based on superposition principle), Bilateral/Unilateral (based on direction of current), and Time-invariant/Time-variant (based on parameter constancy over time).
Derive the expressions for the equivalent inductance when two inductances are connected in: (i) Series adding (ii) Series opposition (iii) Parallel.
Answer
Consider two inductors L1 and L2 with mutual inductance M.
(i) Series Adding: When connected in series such that flux produced by both aids each other, the total inductance is:
(ii) Series Opposition: When connected such that flux produced by one opposes the other, the total inductance is:
(iii) Parallel: For two inductors in parallel with mutual coupling M, the equivalent inductance is derived from the voltage balance equations:
The sign in the denominator depends on whether the coupling is additive or subtractive.
Explain the basic principle of PMMC instruments and compare its performance with permanent magnet moving iron instruments.
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State and explain Kirchhoff’s laws with an example.
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Explain the working principle of DC Generator.
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A 220V, 4-pole, wave connected dc series motor has armature and field resistances of 0.15 Ω and 0.85 Ω respectively. The armature of motor has 60 conductors per pole. The flux developed in the air gap is 20mWb. Find the speed of the motor.
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What is meant by Back EMF? Explain the principle of torque production in a dc motor.
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Calculate the voltage induced in the armature winding of a 4-pole, lap wound DC machine having 728 active conductors and running at 1800 rpm. The flux per pole is 30 mwb.
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Derive the EMF equation of Transformer.
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A single phase transformer has 400 primary and 1000 secondary turns. The net cross sectional area of the core is 60 cm2. If the primary winding is connected to a 50 Hz supply at 520V, Calculate (i) Peak value of flux density in the core (ii) Voltage induced in the secondary winding (iii) Transformation ratio?
Answer
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Explain the principle of operation of a three phase induction motor with a neat sketch.
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A 230/400 V single phase transformer has 800 turns on primary. The maximum flux density in the core is 1.5 Wb/m2. Calculate the number of turns on secondary, area of cross section and maximum flux in the core.
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Explain the working of n-p-n and p-n-p transistors.
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With neat sketch and waveforms, explain the operation of the half wave rectifier?
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Discuss how to measure the voltage, current and frequency with CRO.
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Explain the process of electrostatic and magnetic deflections in CRO.
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