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I B.Tech Semester Supplimentary Examinations, June 2009 NETWORK ANALYSIS ( Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Bio-Medical Engineering, Electronics & Telematics and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆ ⋆ ⋆ ⋆ ⋆
- (a) The following current wave form i(t) is passed through a series R-L circuit with R =2 Ω and L =2 mH. Find the Voltage across each element and sketch the same. (Figure 1a)
Figure 1a (b) Using nodal analysis, determine the Power supplied by 8V Voltage source. (Figure 1b)
Figure 1b (c) Write the Tieset matrix for the graph shown in Figure 1c, taking the tree consisting of branches 2,3,4. [6+6+4]
Figure 1c
- (a) Explain the Dot convention for mutually coupled coils.
(b) Two coils A & B having 100 and 250 turns respectively are wound side by side on a magnetic material having a c.s.area of 10 cm^2 and a mean length of 150 cms The permeability of the material is 500. Determine the self-inductance of the two coils A & B and mutual inductance between them. If the current in coil A changes from zero to 2A in 0.01 seconds, find the Emf induced in the coil B. (c) Derive the relation between the flux density B, and magnetizing force H. Sketch the general shape of B-H curve for both magnetic and nonmagnetic materials. [4+8+4]
- (a) the circuit (Figure 3a) shown, the switch is changes from position 1 to 2 at t=0. Determine the initial conditions i , di/dt , d^2 i/ dt^2 at t=0+
Figure 3a (b) In the parallel resonant circuit, determine the resonance frequency, dynamic resistance and Band width for the circuit (Figure 3b) shown.
Figure 3b (c) When an voltage of 220V A.C supply connected across the AB terminals, the
- Derive the expressions for attenuation constant, phase constant, cut-off frequency and characteristic impedance of a symmetrical Π section. [16]
- (a) What is constant k-filter? What is the difference between constant k-filter and m-derived filter? What are the limitations of constant K-filter? (b) Find the circuit parameters of a constant k-band pass filter having a pass band from 500 Hz and a characteristic resistance of 100Ω. [8+8]
I B.Tech Semester Supplimentary Examinations, June 2009 NETWORK ANALYSIS ( Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Bio-Medical Engineering, Electronics & Telematics and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆ ⋆ ⋆ ⋆ ⋆
- (a) Define Graph and Tree of a Network. (b) Determine the Current through 3 ohms resistor using Nodal method of Analy- sis for Figure 1b.
Figure 1b (c) Draw the graph of the Network shown in Figure 1 and obtain the basic cutset schedule. Choosing one possible tree. [2+8+6]
Figure 1
- (a) Explain the concept of impedance transformation with an ideal transformer. (b) Write down the loop equation for the coupled network shown in Figure 2b.
Figure 4a (b) Determine the current i(t) in a series R-L-C circuit with R=5Ω L=1/2H, C=1/4F with the Voltage applied is a ramp Voltage V(t)=10 r(t-2). Assume initially the circuit is relaxed. [10+6]
- (a) State and explain superposition theorem?
(b) Is superposition theorem valid for power? Substantiate your answer? (c) Determine the current in the 1Ω resistor across A, B of the network shown in Figure 5c using superposition theorem. [4+4+8]
Figure 5c
- (a) Find the y-parameters of the network shown in Figure 6a and there by obtain z-parameters.
Figure 6a (b) Obtain the expressions to get symmetry and reciprocity of a given network in terms of g-parameters. [12+4]
- (a) Draw the circuit of asymmetrical T-attenuator. Write the design equation for the circuit resistances in terms of
i. the image resistances and ii. the image transfer constant θ. (b) Design an asymmetrical T-attenuator to produce attenuation of 20 DB and to work between source impedance of 400Ω and load impedance of 900Ω. [10+6]
- What is constant k band pass filter? Explain the design procedure o this filter? [16]
Figure 2a (b) The numbers of turns in two coupled coils are 600 and 1700 turns respectively. When a current of 6A flow in coil 2 the total flux in the coil is 0.8mwb and the flux linking with the first coil is 0.5mwb.Calculate L 1 , L2,M and coefficient of coupling. (c) A1500 turns coil surrounds a magnetic circuit which has a reluctance of 6*10^6 AT/wb. Calculate the inductance of the coil. [5+7+4]
- (a) Define Q-factor. Derive an equation showing the relation between Q-factor and bandwidth. What is selectivity? How it is related to Q-factor. (b) In the circuit (Figure 3b) shown, the switch is closed on the position 1 at t= there by applied a D.C voltage of 100V to series R-L circuit. At t=500μsec, the switch is moved to position 2 obtain the expression for current i(t) in the both intervals sketch i(t).
Figure 3b (c) Obtain the branch currents and total current in the circuit (Figure 3) shown if applied voltage is 150⊥ 450 V and draw the phasor diagram. [5+7+4]
Figure 3
- (a) The switch in the circuit (Figure 4a) shown is closed at t=0.The excitation V(t)=0.1 e−^3 tu(t). Assuming relaxed conditions, for the circuit, determine i(t) for t >0 Use LaplaceTransform method.
Figure 4a (b) Find the RMS and Average values of the wave form it Vm =100Volts.(Figure
- [8+8]
Figure 4
- (a) How do you say duality exists between Thevenins theorem and Norton’s the- orem? (b) Determine the current through 2.5Ω resistor using Thevenin’s theorem in the network shown in Figure 5b.
Figure 5b (c) For the above circuit shown in Figure, Draw the Nortons equivalent circuit across x and y terminals. [4+8+4]
- (a) Obtain the expressions of ABCD parameters in terms of z parameters.
(b) Determine the ABCD parameters of given network as shown in Figure 6. [6+10]
I B.Tech Semester Supplimentary Examinations, June 2009 NETWORK ANALYSIS ( Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Bio-Medical Engineering, Electronics & Telematics and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆ ⋆ ⋆ ⋆ ⋆
- (a) Distinguish between i. Active and Passive elements ii. Independent and dependent sources (b) Find I 1 ,I 2 and V in the network shown in Figure 1b. Using nodal analysis.
Figure 1b (c) Obtain the basic cutset matrix for the network graph shown in Figure 1 and hence write down the network equations,Take 1,2,3 as Tree branches. [4+8+4]
Figure 1
- (a) Explain the Dot Convention for mutually coupled coils. (b) Derive the Expression for coefficient coupling between pair of magnetically coupled coils. (c) Write the Loop Equations for the Coupled circuit shown in Figure 2.[3+5+8]
Figure 2
- (a) A series R-L-C circuit has a resistance of 8Ω and resonates at 250Hz. Band- width of the circuit is 50Hz. Determine the values of L and C in the circuit. (b) A sinusoidal voltage 25sin 10t is applied at Time t=0 to a series R-L circuit having R=5Ω and L=1H Find i(t) and sketch it .Assume Zero current through the inductor before applying the voltage. [6+10]
- (a) The switch in the circuit (Figure 4a) shown is closed at t=0.The excitation V(t)=0.1 e−^3 tu(t). Assuming relaxed conditions, for the circuit, determine i(t) for t >0 Use LaplaceTransform method.
Figure 4a (b) Find the RMS and Average values of the wave form it Vm =100Volts.(Figure
- [8+8]
Figure 4
- (a) State and explain Milliman’s theorem?
(b) Obtain VAB by Milliman’s theorem and verify your result by Thevenin’s the- orem. Refer Figure 5. [6+10]
