MU Electronics Engineering (Semester 3)
Circuit Theory
December 2013
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) Find the current through 15? resistor

4 M
1 (b) Obtain the voltage response of series R-L circuit
4 M
1 (c) Determine V1/l1 and V2/l1 for the given network

4 M
1 (d) What are standing waves? Define reflection coefficient and VSWR of a transmission line
4 M
1 (e) A ?-section filter network consist of a series arm conductor of 20 mH and two shunt arm capacitor of 160 nF each.
Calculate : (i) cut off frequency (ii) attenuation (iii) Phase shift at 15kHz.
Also obtain the impedance in pass-band
4 M

2 (a) Find I1 through 10? by Thevinin's theorem

6 M
2 (b) Find Ic and Vc for t>o

8 M
2 (c) Use Nodal analysis to find the voltage drop across 4? and 10? ref Qu. 2(a)
6 M

3 (a) Design a single stub match for a load of 150? + j232.5? for 75? line at 500MHz using Smith Chart
8 M
3 (b) Compare foster realization with caurer realizations
8 M
3 (c) State the properties of Hurwitz polynomial
4 M

4 (a) Define T-parameters and relate them to other parameter as indicated.
(i) A and C interms of z-parameters
(ii) B interms of y-parameters
(iii) D interms of h-parameter
8 M
4 (b) Test whether the following functions are positive real functions with proper reasons.
$F_1\left(s\right)=\frac{2s^3+2s^2+3s+2}{s^2+1}$
$F_2\left(s\right)=\frac{s^2+1}{s\left(s^2+4\right)}$
12 M

5 (a) What are scattering parameters? State their properties
6 M
5 (b) Derive an expression of m-derived ? section network starting from a constant k section
6 M
5 (c) For given circuit, switch 's' is opened at t=0. switch 's' was on for long time. Determine $V_L\left(0^+\right),\frac{dV_L}{dt}\left(0^+\right)\ and\frac{d^2V_L}{dt^2}\left(0^+\right)$

8 M

6 (a) Explain the graphical representation of series resonance circuit
6 M
6 (b) Test whether following polynomials are Hurwitz
(i) P(s)=s4+s3+5s2+3s+4
(ii) P(s)=s6+6s4+4s2+2
8 M
6 (c) Find the characteristics impedance, cut off frequency and pass band for the network shown :

6 M

More question papers from Circuit Theory