R7100406-network-analysis

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1

Code No: R7100406

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 NETWORK ANALYSIS (Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Electronics & Control Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. A circuit consisting of three resistances 12 Ω, 18Ω and 36 Ω respectively joined in parallel is connected in series with a fourth resistance. The whole circuit is applied with 60V and it is found that the power dissipated in the 12 Ω resistor is 36 W. Determine the value of the fourth resistance and the total power dissipated in the circuit. [16] 2. Write short notes on

[4×4]

(a) Flux linkage (b) Self-induction (c) Mutual inductance (d) Lenz’s law. 3. Analyse the current relationship and the voltage relationship in a 3 phase star connected system. Also derive the equation for power in such a system. [16] 4. Draw the oriented network graph from the incidence matrix given below. Nodes A B C D

[16]

Branches 1 2 3 4 5 6 -1 0 0 +1 -1 0 +1 -1 0 0 0 -1 0 +1 -1 0 +1 0 0 0 +1 -1 0 +1

5. (a) State and explain Thevenin’s Theorem. (b) What are the limitations of Thevenin’s Theorem. (c) Explain the steps to apply Thevenin’s Theorem and draw the Thevenin’s equivalent circuit. [6+4+6] 6. Derive the relationship between Y parameters and Z - parameters.

[16]

7. A Series RL circuit with R = 10 Ω, L = 0.2 H has a constant voltage of V = 50 V applied at t = 0. Find the time response of the current. [16] 8. Design a symmetrical T attenuator to give 20 db attenuation to have a characteristic impedance of 75 Ω. [16] ?????

2

Code No: R7100406

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 NETWORK ANALYSIS (Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Electronics & Control Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. (a) Derive the expression for energy stored in an indicator. (b) A 50 ohm resistor is in parallel with a 100 ohm resistor. The current in 50 ohm resistor is 7.2A What is the value of third resistance to be added in parallel to make the line current as 12.1A? [6+10] 2. Derive expressions for voltage, current and power in a resistor supplied with an alternating sinusoidal voltage. [16] 3. (a) Define half power frequency. Draw a sketch and explain. (b) Derive the formula for half power frequencies.

[6+10]

4. Derive the expression for resonant frequency of a parallel circuit having R1 and L in one branch and R2 and C in the second branch. [16] 5. State and Explain with proof of Reciprocity Theorem.

[16]

6. Discuss on the steps involved in the ladder network to lattice network conversion. [16] 7. A series RLC circuit with R = 5Ω, L = 0.1 H and C = 500µF has a constant voltage V = 10 volts applied at t = 0. Find the resulting current. Assume zero initial conditions. [16] 8. Design an m - derived LPF for Rk = 600 ohm, fc = 1800 = 3600 Hz. ?????

[16]

3

Code No: R7100406

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 NETWORK ANALYSIS (Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Electronics & Control Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Two resistors R1 = 2500 Ω and R2 = 4000 Ω are joined in series and connected to a 100 V supply. The voltage drop across R1 and R2 are measured successively by a volt meter having a resistance of 50000 Ω. Find the sum of the readings. [16] 2. In an AC circuit the applied voltage is given by v = 200 sin314t and the expression for the leading current is given by i = 10 cos 314t. Find the circuit constant and find the power factor of the circuit and draw the phasor diagram. [16] 3. A balanced delta connected load of (8 + j6) ? Ω / phase is connected to a 3 phase, 230V supply. Find the line current, power factor, power, reactive volt-amperes and total volt-amperes. Also draw the phasor diagram. [16] 4. A series RLC circuit has R = 5 ohms, L = 0.01 H, C = 10 micro farads. Calculate the resonant frequency, Q factor and band width. [16] 5. (a) State and explain Thevenin’s Theorem. (b) What are the limitations of Thevenin’s Theorem. (c) Explain the steps to apply Thevenin’s Theorem and draw the Thevenin’s equivalent circuit. [6+4+6] 6. Derive ABCD parameters from Z parameters.

[16]

7. A 50 Hz, 400V (peak value) sinusoidal voltage is applied at t = 0 to a series RL circuit having resistance of 5Ω and inductance 0.2 H. Obtain an expression of current at an instant ‘t’. Calculate the value of the transient current 0.01 seconds after switching on. [16] 8. Categorize filters and explain.

[16] ?????

4

Code No: R7100406

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 NETWORK ANALYSIS (Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering, Electronics & Control Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. A circuit consisting of three resistances 12 Ω, 18Ω and 36 Ω respectively joined in parallel is connected in series with a fourth resistance. The whole circuit is applied with 60V and it is found that the power dissipated in the 12 Ω resistor is 36 W. Determine the value of the fourth resistance and the total power dissipated in the circuit. [16] 2. A metal filament lamp, rated at 750 Watts, 100V is to be connected in series with a capacitor across a 230V, 60 Hz supply. Calculate [16] (a) The capacitance required (b) The power factor. 3. A series RLC resonant circuit has Q = 100 and band width 2000 Hz. If C = 50 pF, what are the values of R and L. find the voltages across R, L and C when 5 V is applied across the circuit. Also draw the resonance curve. [16] 4. A symmetrical 3 phase, 400 V system supplies a balanced mesh connected load. The current in each branch circuit is 20A and the phase angle is 40deg lag. Find (a) the line current (b) the total power.

[16]

5. (a) State and explain Thevenin’s Theorem. (b) What are the limitations of Thevenin’s Theorem. (c) Explain the steps to apply Thevenin’s Theorem and draw the Thevenin’s equivalent circuit. [6+4+6] 6. The Z - parameters of a two port network are Z11 = 10Ω, Z22 = 20Ω, Z12 = Z21 = 5Ω. (a) Find the ABCD parameters (b) Find the equivalent T network.

[16]

7. Derive an expression for the current response in RL series circuit with a sinusoidal source. [16] 8. Categorize filters and explain.

[16] ?????