Code:
DE07
Subject: NETWORK AND TRANSMISSION LINES
Time: 3 Hours Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and carries 20 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.
· Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.
· Any required data not explicitly given, may be suitably assumed and stated.
Q.1 Choose the correct or best alternative in the following: (2x10)
a. In a series parallel circuit, any two resistances in the same current path must be in-:
(A) Parallel with each other (B) Series with each other
(C) Parallel with the voltage source (D) Series with the voltage source
b. Superposition theorem is not applicable in:
(A) Voltage responses (B) Power responses
(C) Current responses (D) All the three
c. Kirchhoff’s first law is used in the formation of:
(A) Loop equations (B) Nodal equations
(C) Both (D) None of the above
d. Bridged T network can be used as:
(A) Attenuator (B) Low pass filter
(C) High pass filter (D) Band pass filter
e. One neper is equal to
(A) 0.8686 dB (B) 8.686 dB
(C) 118.686 dB (D) 86.86 dB
f. Total reflection can take place if the load is:
(A)
0
(B) 
(C) 0 and
(D) Zo
g. The characteristic impedance of a distortion less line is:
(A) Real (B) Inductive
(C) Capacitive (D) Complex
h. Terminating half sections used in composite filters are built with the following value of m:
(A) m = 0.6 (B) m = 0.8
(C) m = 0.3 (D) m = 1
i. A transmission line works as an
(A) Attenuator (B) LPF
(C) HPF (D) Neither of the above
j. In a loss free RLC circuit the transient current is:
(A) Sinusoidal (B) Square wave
(C) Oscillating (D) Non-oscillating
Answer any FIVE Questions out of EIGHT Questions.
Each question carries 16 marks.
Q.2 a. State and prove Maximum power transfer theorem. (8)
b. Calculate the value of RL which will be drawing maximum power from the
circuit of Fig.-1. Also find the maximum power. (8)
Q.3 a. A
capacitor of 10
capacitance is charged to a
potential difference of 200 V and
then connected in parallel with an
uncharged capacitor of
30
. Calculate
(i) The potential difference across the parallel combination.
(ii) Energy stored by each capacitor. (8)
b. Explain Z parameters and also draw an equivalent circuit of the Z parameter model of the two port network. (8)
Q.4 a. Explain reflection coefficient and VSWR of a transmission line. (8)
b. Explain stub matching in a transmission line. (8)
Q.5 a. Derive an expression for a condition of minimum attenuation in a transmission line. (8)
b. A loss free transmission line has an inductance of 1.2 mH/km and a capacitance of 0.05μF/km. Calculate the characteristics impedance and propagation constant of the line. (8)
Q.6 a. Derive an expression for design impedance of a symmetrical T attenuator. (8)
b. Design a T type symmetrical attenuator which offers 40 dB attenuation with a load of 400 Ω. (8)
Q.7 a. A symmetrical T section has the following O.C. and S.C. impedances:
Zo/c = 800 ohms Zsc = 600 ohms Determine T section parameters to
represent the two port network. (8)
b. Explain how the reactance and impedance of a high pass filter varies with frequency. (8)
Q.8 a. Differentiate between: (8)
(i) Unilateral and Bilateral elements. Give examples.
(ii) Distributed and lumped elements.
b. Define unit step, Sinusoidal, Cosinusoidal
function. Derive the
Q.9 a. Drive the expression of resonant frequency for a parallel R-L-C circuit in
terms of Q, R, L and C. (8)
b. For a series resonant circuit, R=5Ω, L=1H and C=0.25μf. Find the resonance frequency and band width. (8)