Question Paper: Circuit Theory : Question Paper Dec 2013 - Electronics Engineering (Semester 3) | Mumbai University (MU)
0

## Circuit Theory - Dec 2013

### Electronics Engineering (Semester 3)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.
1 (a) Find the current through 15? resistor (4 marks) 1 (b) Obtain the voltage response of series R-L circuit(4 marks) 1 (c) Determine V1/l1 and V2/l1 for the given network (4 marks) 1 (d) What are standing waves? Define reflection coefficient and VSWR of a transmission line(4 marks) 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 marks)
2 (a) Find I1 through 10? by Thevinin's theorem (6 marks) 2 (b) Find Ic and Vc for t>o (8 marks) 2 (c) Use Nodal analysis to find the voltage drop across 4? and 10? ref Qu. 2(a)(6 marks) 3 (a) Design a single stub match for a load of 150? + j232.5? for 75? line at 500MHz using Smith Chart(8 marks) 3 (b) Compare foster realization with caurer realizations(8 marks) 3 (c) State the properties of Hurwitz polynomial(4 marks) 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 marks)
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 marks)
5 (a) What are scattering parameters? State their properties(6 marks) 5 (b) Derive an expression of m-derived ? section network starting from a constant k section (6 marks) 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 marks) 6 (a) Explain the graphical representation of series resonance circuit(6 marks) 6 (b) Test whether following polynomials are Hurwitz
(i) P(s)=s4+s3+5s2+3s+4
(ii) P(s)=s6+6s4+4s2+2
(8 marks)
6 (c) Find the characteristics impedance, cut off frequency and pass band for the network shown : (6 marks)