Electronic Circuits - Dec 2013

Computer Science Engg. (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Explain the criteria for selecting a suitable operating point and factors affecting the stability.(8 marks) 1 (b) Determine the operating point for a fixed bias circuit shown in Fig.Q1(b). Given β=100 and V_BE=07V. Draw the load line (7 marks) 1 (c) Explain transistor as a switch.(5 marks) 2 (a) What are the differences between BJTs and FETs?(6 marks) 2 (b) Explain the working of a CMOS inverter.(4 marks) 2 (c) Explain the construction, working and principle of operation of an n-channel JFET.(10 marks) 3 (a) Explain the classification of optoelectronic devices.(6 marks) 3 (b) Define the following terms:
(i) Responsivity
(ii) NEP
(iii) Response time
(iv) Quantum efficiency(4 marks) 3 (c) Explain the working of cathode ray tube with a neat diagram. What are the advantages and disadvantages of CRT?(10 marks) 4 (a) What is the need for cascading amplifier? Explain two stage cascaded amplifier with a block diagram.(8 marks) 4 (b) Derive the expression for:
(i) Current gain
(ii) Input impedance
(iii) Voltage gain
(iv) Output admitance(12 marks) 5 (a) Briefly explain the classification amplifier based on input and output parameter of interest [V_i, V_o, I_i and i_o](12 marks) 5 (b) With a neat diagram, explain amplifier with negative feed back.(4 marks) 5 (c) Calculate the values of harmonic distortion components for an output signal having an amplitude of 5V at fundamental frequency, second harmonic component of 0.05V and find total harmonic distortion.(4 marks) 6 (a) What are necessary conditions for loop gain and phase shift for sustained oscillations according to Barkhausen criterion?(4 marks) 6 (b) Explain the working of an Astable multivibrator using IC 555 timer with circuit diagram and relevant waveforms.(8 marks) 6 (c) Explain the working of RC low pass RC high pass circuit.(8 marks) 7 (a) Explain the steps involved in custom design of mains transformer.(6 marks) 7 (b) What are SMPS? Compare linear power supplies with SMPS.(7 marks) 7 (c) Explain the working of three terminal voltage regulators.(7 marks) 8 (a) What should be the slew rate choosen for an OPAMP as an inverting amplifier configuration with gain of 10 when input is a sinusoidal signal with peak to peak value of 2V and highest frequency expected is 50 Hz?(4 marks) 8 (b) Explain the working of an OPAMP window comparator with circuit diagram.(8 marks) 8 (c) Explain the lead and tag type of phase shifter.(8 marks)