USN
Third Semester B E Degree Examination, December 2018
Electric Circuit Analysis
Time: 3 Hours Max. Marks: 100
Note: Answer FIVE full Questions choosing one full question from each module.
1.
a. Reduce the network into equivalent circuit between A B terminals by stardelta
transformation for the network shown in fig (1.a). 10M
b. Using mesh current analysis finds loop currents for the circuit shown in fig (1.b).
10M
OR
2.
a. Using source transformation find the power delivered by 50 V source in given
network of fig 2 10M
b. Find all node voltages for the circuit shown in fig using node analysis.
17EE32
3.
a. State and prove Superposition Theorem. 10M
b. Prove Reciprocity Theorem for the circuits shown in fig (3.b). 10M
OR
4.
a. Find the Thevenin's equivalent ckt of the ckt shown in fig(4.a). 10M
b. Find Norton's equivalent circuit at the terminals shown in fig (4.b). 10M
5.
a. Show that in series resonant circuit the resonant frequency is equal to the
geometric mean of half power frequencies. 10M
b. A two branch anti resonance ckt contains L=0.4H C=40 microF. Resonance is
to be achieved by variation of RL RC. calculate the resonant frequency for the
following cases 10M
i. RL=120 ohm, RC=80 ohm
ii RL=100 ohm, RC=100 ohm
OR
6.
a. Show that
i. The voltage of a capacitor cannot Change instantly. 10M
ii The current in an inductor cannot change instantly.
b. For the ckt sown in fig find Vc at t=∞ 10M
7.
a. State and Prove Initial and final value theorem. 10M
b. Find Laplace of the saw tooth waveform shown in fig 7.b 10M
Fig 7.b
OR
8.
a. Obtain the Laplace transform of ramp function ii) exponential
function e-at iii) sinusoidal function sinωt iv)
v)impulse function 10M
b. Obtain Laplace Transform of system shown in fig(8.b). 10M
Fig 8.b
9.
a. Define two port networks and Give expression for T parameters. 10M
b. Following short circuit currents and voltages are obtained experimentally for a
two port network: Determine Y parameters 10M
With output short circuited I1= 5mA I2=-0.3mA and V1=25 V
ii) With input short circuited I1= I2=10mA and V2=30 V
OR
10.
c. Express Z parameters in terms of Y parameters. 10M
d. Following are the hybrid parameters for a network Determine the Y
parameters for the network 10M