JNTU
JNTU B.Tech II NETWORK THEORY Previous Question Paper (November/December - 2017 - R16)
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.
Part A
Give the advantages and disadvantages of tie-set matrix.
Answer
The tie-set matrix provides a systematic method for writing KVL equations for any network. Its advantage is that it ensures the independence of loop equations. The disadvantage is that it requires the selection of a tree and the determination of fundamental loops, which can be computationally intensive for complex networks.
Write the expression for total inductance of the three series connected coupled coils connected between A and B as shown in circuit shown in figure 1.
Answer
For three series-connected coupled coils with self-inductances L1, L2, and L3 and mutual inductances M12, M23, and M13, the total equivalent inductance L_eq is given by:
The sign of the mutual inductance terms depends on whether the coils are connected in series-aiding or series-opposing configurations relative to the current flow.
What are the advantages of poly phase system over single phase system?
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Explain the effect of power factor on wattmeter readings in two wattmeter method.
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Explain why the current in inductance does not change in zero time.
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Write a short note on the procedure employed to evaluate initial conditions.
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Define active and passive ports.
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Express Z-parameters in terms of ABCD parameters.
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List out the disadvantages of constant – k filters.
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Sketch the frequency response of high pass filters.
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Part B
Determine voltage V across a 15 ohms resistor in the magnetically coupled circuit shown in Figure 2. Take Vs = 30∠40 degrees.
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For the graph shown in Figure 3, write the incidence matrix. Express branch voltage in terms of node voltages and then write a loop matrix and express branch currents in terms of loop currents.
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Derive the relation between line and phase voltages and currents for a balanced STAR connected system.
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The two watt meter readings in a 3-phase power measurement are 8 KW. The latter reading is being obtained after the reversal of current coil. Calculate the total power, Active Power, Reactive power and power factor of the load.
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A three phase balanced delta connected load of (9+j2) ohm is connected across a 400V, 3ϕ balanced supply. Determine the phase currents and line currents. Assume the phase of sequence to be RYB. Also calculate the power drawn by load.
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With the switch open steady state is reached with V =100 sin 314 t volts. The switch is closed at t=0. The circuit is allowed to come to steady state again. Determine steady state current and complete solution of transient current (figure 4).
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Obtain the expression for i(t) for a series RL circuit when exited by a source of V(t)=Vm sin (wt+θ) using Laplace transform.
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Find the Y-parameters for the circuit shown in figure 5.
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The Z-parameters of a two- port network are Z11=15Ω, Z12=Z21=6Ω and Z22=24Ω. Determine ABCD parameters.
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Design a band pass filter with cutoff frequencies of 2000Hz and 5000Hz with a design impedance of 500 ohms.
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Design a m-derived low filter with a design impedance of 300Ω and the cut off frequency at 2 KHz and infinite attenuation at 2345Hz.
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