Electronics And Communication Engineering (Semester 3)
Total marks: 80
Total time: 3 Hours
INSTRUCTIONS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Draw neat diagrams wherever necessary.
PART-A
1.a.
What is an Ideal transformer?
(2 marks)
00
1.b.
Discuss the dot convention between magnetically coupled coils.
(3 marks)
00
1.c.
What is resonance? Explain.
(2 marks)
00
1.d.
What is the significance of power factor?
(3 marks)
00
1.e.
Explain the significance of average value.
(2 marks)
00
1.f.
What are the Laplace transform of step and exponential functions?
(3 marks)
00
1.g.
Define poles and zeros in a transfer function.
(2 marks)
00
1.h.
What is a driving point in transfer function? Explain.
(3 marks)
00
1.i.
Write the properties of LC Networks.
(2 marks)
00
1.j.
State Foster's Reactance theorem.
(3 marks)
00
PART-B
Unit-I
2.a.
Clearly explain the following:
Self inductance (L)
Mutual inductance (M)
(5 marks)
00
2.b.
An Iron ring of mean length 50 cms has an air gap of 1 mm and a winding of 200 turns. If the relative permeability of the Iron is 400, when a current of 1 Amp flows in the winding. Determine the flux density Neglect leakage and fringing.
(5 marks)
00
OR
3.a.
Define and explain the following with an example :
Oriented Graph.
Tree of a Graph.
Tie set and a basic Tie set.
Cut set and a basic Cut set.
(10 marks)
00
Unit-II
4.a.
R-C series circuit is suddenly excited from a step voltage V. Derive an expression for the currents as a function of time and draw the graph current Vs Time.
(5 marks)
00
4.b.
An inductive coil of Resistance R and inductance L is connected in parallel with a capacitor C. Derive the expression for resonant frequency and Q factor.
(5 marks)
00
OR
5.a
A series RLC circuit is connected across a variable frequency supply and has R= 12 ohms, L = 1 mH and C = 1000 pF. Calculate
Resonant frequency
Q factor
Half power frequencies. Derive the formulae used
(10 marks)
00
Unit-III
6.a.
Derive expression for R.M.S and average value of a sinusoidal alternating quantity.
(5 marks)
00
6.b.
A pure inductance of 5 mH carries a current of the wave form shown in the figure. Sketch the waveform of V(t) and P(t). Determine the average value of power.
(5 marks)
00
OR
7.a.
A capacitor of 100 $\mu$F is connected across 200 V, 50 Hz, Single phase supply. Calculate :
The reactance of the capacitor
RMS value of the current
The maximum value of the current
(5 marks)
00
7.b,
When an impulse voltage is impressed across R-C circuit, derive an expression for its current response.
(5 marks)
00
Unit-IV
8.a.
Determine the 'h' parameters of the network shown in the figure
(5 marks)
00
8.b.
Define Z and Y parameters of a two port network and determine the relationship between the above parameters.
(5 marks)
00
OR
9.a.
Explain clearly the following terms :
Propagation constant and characteristics impedance.
Attenuation constant
(5 marks)
00
Unit-V
10.a.
What is a high pass filter? In what respects it is different from a low pass filter?
(5 marks)
00
10.b.
Derive the equation to find the inductances and capacitances of a constant K high pass filter.
(5 marks)
00
OR
11.a.
Explain the variation of Attenuation, phase shift and characteristic impedance of Band pass filter.
(5 marks)
00
11.b.D
Draw the circuit diagram for T and $\pi$ sections of composite filter.
(5 marks)
00
teamques10
★ 70k
and 3 others joined a min ago.