I B.Tech - Regular Examinations, June 2009
First Year
ELECTRICAL CIRCUITS ANALYSIS- SET NO: 2
(Regulation 2007)
Time : 3 hours |
Maximam Marks:80 |
Answer any FIVE Questions
1. (a)A bridge network ABCD is arranged as follows:
Resistance between terminals AB, BC, CD, DA and BD are 10 ohms, 30 ohms,
15 ohms, 20 ohms and 40 ohms respectively. A 4V battery is connected with
negligible internal resistance between terminals A and C. Determine the cur-
rent through each element in the network using network reduction techniques.
(b) Three equal resistances are available. Find
i. Two ratios of the equivalent resistances when they are connected in par-
allel.
ii. The ratio of the current through each elements when they are connected
in parallel.
2.(a)An iron ring has a mean circumferential length of 60cm and a uniform winding
of 300 turns. An air gap has been made by a saw cut across the section of the
ring. When a current of 1A flows through the coil, the flux density in the air
gap is found to be 0.126mb/m
2. How long is the air gap? Assume iron has a
relative permeability of 300.
(b)A steel ring of 25cm mean diameter and of circular section of 3cm in diameter
has an air gap of 1.5mm length. It is wound uniformly with 700 turns of wire
carrying a current of 2A. Calculate.
i. Magneto motive force.
ii. Flux density
iii. magnetic flux
iv. Relative permeability of steel ring..
3. (a)Why the rms values of an alternating quantity is more important than its average
value. Find the rms value of the resultant current in a conductor which carries
simultaneously sinusoidal alternating current with a maximum value of 15A and
direct current of 15A, by deriving necessary expressions.
4.(a)A symmetrical 3-phase, 3-wire, 440V supply is connected to a star connected load.
The impedances in each branch are : Z1=(2+j3)
, Z2=(1-j2)
, Z3=(3+j4)
. Find
its equivalent delta connected load. Hence find the phase and line currents and the
total power consumed in the circuits.
5.(a) Draw the oriented network graph from the incidence matrix given below.
(b) Draw the oriented network graph from the incidence matrix given below.
6.(a) State and explain Norton’s theorem.
(b) For the circuit shown in figure 6b, find the value of current through 1 ohm in
the arm PQ using Thevenin’s theorem.
7.A series RLC circuit with R = 4 K
, L = 10 H and C = 100 µF has a constant
voltage of 60 V applied at t = 0. Find the current transient and the maximum
current, if the circuit is initially relaxed.
8.8. (a)Find the Z - parameters of the lattice network shown in figure 8a:
(b)Find the Y - parameters for the n/w shown in figure 8b:
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