College : Vardhaman College Of Engineering
Degree : B.Tech
Semester : I
Subject : Basic Electrical Engineering
Document type : Question Paper
Website : vardhaman.org
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Basic Electrical Engineering Question Paper :
VARDHAMAN COLLEGE OF ENGINEERING
(AUTONOMOUS)
B. Tech I Semester Supplementary Examinations December – 2013
(Regulations : VCE-R11A)
(Common to Information Technology, Electronics and Communication Engineering &
Electrical and Electronics Engineering)
Date : 30 December – 2013
Time: 3 hours
Max Marks: 75
Related : Vardhaman College Of Engineering Technical English B.Tech Question Paper : www.pdfquestion.in/6292.html
Answer ONE question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
Unit – I :
1. a) Find current in all branches for the network shown in fig.1 fig.1 6M
b) Using source transformation, replace the circuit shown in fig.2. by a practical voltage source between A& B fig.2 9M
2. a) Write the concept of source transformation technique with suitable examples. 8M
b) Determine the current in resistor 10O in the circuit given in fig.3 and find Vs. 7M
UNIT-II :
3. a) Explain super mesh and super node analysis. 7M
b) Using Nodal Analysis, find voltages V1 and V2 in the network in Fig 4(b) Fig 4(b) 8M
4. a) Deduce the expressions used in conversion of Y to ? and ? to Y transformations. 5M
b) Determine the equivalent resistance between the terminals A&B for the network shown in fig.5 10M
UNIT-III :
5. a) Define power factor, frequency, phase and phase difference of AC quantities with neat sketches. 8M
b) An alternating voltage of V = 100 Sin 376.8t is applied to a circuit consisting of a coil having a resistance of 6 ohm and an inductance of 21.22mH
i. Find the expression for instantaneous current
ii. Calculate the RMS voltage, real power and frequency 7M
6. a) Derive the expression for the resonant frequency of a parallel AC circuit. Draw the relevant circuit diagram. 7M
b) A coil having 6 Ohm resistor and inductance of 25.5mH is energized from 440V, 50Hz supply calculate the current to make the overall p.f. to unity what value of capacitor is to be connected is parallel with the coil. Draw the vector diagram. 8M
UNIT-IV :
7. a) Explain and derive the expression for self inductance and mutual inductance. 5M
b) A circuit has 800 turns enclosing a magnetic circuit 15cm2 in section. With 5A flowing in the circuit, the flux density is 0.8 wb/m2 and with 10A the flux density increases to 1.2 wb/m2. Find
i. The mean value of the inductance between these current limits.
ii. The induced emf when the current falls uniformly from 10A to 5A in 0.04 sec. 10M
8. a) Compare electric and Magnetic circuits. 5M
b) A cast steel electromagnetic has an air gap length of 3mm and an iron path of length 40 cm. Find the number of ampere – turns necessary to produce a flux density of 0.7 wb/m2 in the gap. Neglect leakage and fringing. (consider H = 660 At/m for B = 0.7 wb/m2) 10M
UNIT-V :
9. a) Explain graph , tree, tie set and cut set with example. 8M
b) What are Z parameters of a 2 port network. Find the Z parameters of the 2 port circuit shown in fig.6 7M
10. a) Write short notes on:
i. H parameters
ii. ABCD parameters 7M
b) Obtain the dual of the network shown in fig.7 8M
B. Tech I Semester Regular Examinations, February – 2014 :
Regulations: VCE-R11A
Basic Electrical Engineering :
(Common to Information Technology, Electronics and Communication Engineering & Electrical and Electronics Engineering)
Date : 10 February, 2014
Time : 3 Hours
Max. Marks : 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
Unit – I :
1. a) What is an electrical circuit? Differentiate between
i. Active and passive elements
ii. Independent and dependent sources 8M
b) Use Kirchhoff’s laws, determine the currents flowing in each branch of the network shown in fig.1. 7M
2. a) Assume ‘n’ number of resistors is connected in series and entire combination is supplied by a single DC voltage source of ‘V’ volts. Prove that, the voltage drop across ‘nth’ resistor is directly proportional to the supply voltage ‘V’ volts. 7M
b) For the network shown in fig.2, determine the total power consumed in 0.8 O resistor by source transformation method. 8M
Unit – II :
3. a) A star network in which N is star point made up as follows. AN=70O, BN=100O, CN=90O. Find an equivalent delta network. 7M
b) In the network shown in fig.3, find the current in the 10O resistor using nodal equations by inspection. fig.3 8M
4. a) Using nodal analysis, find the node voltages V1 and V2 in fig.4. fig.4 6M
b) Write the mesh current matrix equation for the network shown in fig.5 and solve for the currents. 9M fig.5
Unit – III :
5. a) Find the average and effective values of
i. Cosine wave v(t)=Vm cos (?t+?)
ii. Half-rectified sine wave 8M
b) The voltages across two series connected circuit elements are v1=100 sin?t V and v2=50 sin (?t-300) V. If the circuit current is (4+j2) A, find the complex power of the circuit. 7M
6. a) A capacitor C is connected in series with a 40 O resistor across a supply of frequency 60 Hz. A current of 3 A flows and the circuit impedance is 50 O. Calculate
i. The value of Capacitance C,
ii. The supply voltage,
iii. The phase angle between the supply voltage and current
iv. The PD across the resistor and capacitor. Draw the phasor diagram. 7M
b) A 10 O is in series with a 2 O capacitive reactance and the combination is connected across a 5 O resistor. If the input current to this combination is 0 10 0 A. Find the power factor of the circuit. 8M