JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II ELECTRICAL CIRCUITS Previous Question Paper (April/May - 2018 - R15)
Part A is compulsory. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit.
Part A
Define the Independent and Dependent Sources. How they are classified?
Answer
An independent source is a voltage or current source whose value is completely independent of any other circuit variable. A dependent (controlled) source is one whose output voltage or current depends on the voltage or current elsewhere in the circuit. They are classified into four types: Voltage-Controlled Voltage Source (VCVS), Voltage-Controlled Current Source (VCCS), Current-Controlled Voltage Source (CCVS), and Current-Controlled Current Source (CCCS).
What is meant by Super Mesh?
Answer
A Super Mesh is created when two meshes share a common current source. To solve, the current source is treated as a single super mesh by excluding the branch containing the source, and a constraint equation is written relating the two mesh currents to the source current.
Define the R.M.S. value of a periodic waveform.
Answer
Sign in to view the complete answer paper.
What is the significance of J-operator? What are the different forms of expressing the sinusoidal quantity in complex form?
Answer
Sign in to view the complete answer paper.
What is the need of locus diagrams?
Answer
Sign in to view the complete answer paper.
State the Faraday’s laws of electromagnetic induction.
Answer
Sign in to view the complete answer paper.
Write the Definition of Graph and Tree.
Answer
Sign in to view the complete answer paper.
What is the procedure for constructing the dual network of a given network?
Answer
Sign in to view the complete answer paper.
Write the procedure to verify the superposition theorem.
Answer
Sign in to view the complete answer paper.
State the Nortons theorem.
Answer
Sign in to view the complete answer paper.
Unit I
A Wheatstone bridge consists of AB=4Ω, BC=3Ω, CD=6Ω and DA=5Ω. A 2.4V cell is connected between B and D and a galvanometer of 8Ω is connected between A and C. Find the current through the galvanometer.
Answer
Sign in to view the complete answer paper.
By using voltage division rule find the voltage V1 in the circuit shown in figure 2.
Answer
Sign in to view the complete answer paper.
Two resistances of 50Ω and 40Ω respectively are connected in parallel. A third resistance of 10Ω is connected in series with the combination and a D.C supply of 220 V is applied to the ends of the completed circuit. Calculate the current in each resistance.
Answer
Sign in to view the complete answer paper.
Unit II
A coil of insulated wire of resistance 8Ω and inductance 0.003H is connected to an a.c. supply at 240 V, 50 Hz. Calculate (i) the current, p.f and the power, (ii) the value of capacitance which when connected in series with the above coil, causes no change in the values of the current and power taken from the supply.
Answer
Sign in to view the complete answer paper.
How do you obtain the power factor and power factor angle from (i) Impedance triangle (ii) Admittance triangle (iii) kVA triangle?
Answer
Sign in to view the complete answer paper.
A resistance of 50Ω, an inductance of 0.15H and a capacitance of 100µF are connected in parallel across a 100V, 30Hz supply. Calculate (i) the current in each circuit (ii) the resultant current and (iii) the phase angle between the resultant current and the supply voltage. Draw the phasor diagram.
Answer
Sign in to view the complete answer paper.
Compute the RMS and average values of square wave form shown in figure 3.
Answer
Sign in to view the complete answer paper.
Unit III
Derive the expression for band width of RLC series circuit.
Answer
Sign in to view the complete answer paper.
Self-inductance of two coupled coils are L1 = 10×10^-3 H and L2 = 20×10^-3 H. The coefficient of coupling (K) being 0.75 in the air, find voltage in the second coil, and the flux of first coil, Provided the second coil has 500 turns and the circuit current is I1 = 2 sin 314t A.
Answer
Sign in to view the complete answer paper.
Explain the procedure to draw the locus diagram of R-C series circuit when ‘C’ is varying.
Answer
Sign in to view the complete answer paper.
A mild steel ring has a mean circumference of 600mm and a uniform cross-sectional area of 350 mm^2. Calculate the MMF required producing a flux of 600 µWb when an air gap of 1mm length is now cut in ring. Also determine the flux produced if MMF remains constant. Given relative permeability of mild steel is 1200.
Answer
Sign in to view the complete answer paper.
Unit IV
Illustrate the super mode analysis with an example.
Answer
Sign in to view the complete answer paper.
Find the branch current as shown in following figure 4 by using the concept of tie-set matrix.
Answer
Sign in to view the complete answer paper.
Using nodal analysis technique to determine current ‘I’ in the network shown in figure 5.
Answer
Sign in to view the complete answer paper.
For the network shown in figure 6 determine all branch current and the voltage across the 6Ω resistor by loop current analysis.
Answer
Sign in to view the complete answer paper.
Unit V
Find the current through 4 ohms resistor for the following network shown in figure 7 using Thevenin’s theorem.
Answer
Sign in to view the complete answer paper.
State and explain compensation theorem.
Answer
Sign in to view the complete answer paper.
For the network shown in Figure 8 verify Tellegen’s theorem.
Answer
Sign in to view the complete answer paper.