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Semester : 02 Date :

Subject code : 09BECC204 Maximum marks :100

Subject Name : CIRCUIT THEORY Duration : 3.00 Hours

PART A (1x 20 = 20 Marks) - Time 30 Minutes

On Line Examination

PART B ( 5 X 16 marks) 2 Hrs

21.a (i) Discuss the delta star transformation with neat diagram (6)

(ii) Determine the current flowing in the 2 resistor of the circuit shown in Figure 21.a.

using Kirchhoffs laws. Find also the power dissipated in the 3 resistance. (10)

(OR)

b. (i) For the circuit of Fig. 21.b calculate (a) the current drawn from the source, (b) the p.d.

across each resistor, (c) the current through each resistor, and (d) the power dissipated

by the 5 resistor (10)

[PTO]

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(ii) State and Explain Kirchhoffs Laws (6)

22. a. (i) State and explain the Thevenins theorem. (6)

(ii) UseNortons theorem to determine the current flowing in the 3 resistance of thenetwork shown in Figure 22.a. The voltage source has negligible internal

resistance. (10)

(OR)

b. For the circuit shown in Figure 22. b. find, using the superposition theorem, (a) the

current flowing in and the pd across the 18 resistor, (b) the current in the 8 Vbattery and (c) the current in the 3 V battery (16)

[PTO]

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23. a. A coil of inductance 0.12 H and resistance 3 k is connected in parallel with a 0.02 F

capacitor and is supplied at 40 V at a frequency of 5 kHz. Determine (a) the current in the

coil, and (b) the current in the capacitor. (c) Draw to scale the phasor diagram and

measure the supply current and its phase angle; check the answer by calculation.

Determine (d) the circuit impedance and (e) the power consumed. (16)

(OR)

b. (i) Use nodal analysis to determine the current flowing in each branch of the network

shown in Figure 23. (8)

(ii) Discuss the mesh analysis method with suitable example (8)

24. a. (i) Derive the expression for current i for a series R-C Decaying transient network. (8)(ii) A circuit consists of a resistor connected in series with a 0.5 F capacitor and has a

time constant of 12 ms. Determine (a) the value of the resistor, and (b) the capacitor

voltage 7 ms after connecting the circuit to a 10 V supply. (8)

(OR)

b. Derive an expression with diagram for the (1) Resonance frequency, (2) Quality factor

(3) Bandwidthof a single phase series circuit (16)

25. a.(i) Derive the expression for self inductance and mutual coupling (10)

(ii) Derive the expression for coefficient of coupling (6)

(OR)

b. Discuss about the analysis of a network using concept of cut set with suitable example.

(16)

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