Electronic Devices - Dec 2011

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.

Attempt any four from the following

1 (a) Derive expression for zero temperature drift biasing.(5 marks) 1 (b) Sketch the output waveform of the following circuit: IMAGE(5 marks) 1 (c) Which biasing method can?t be used for DMOSFET? Why?(5 marks) 1 (d) What is the maximum reverse voltage across diode in HWR, FWR (Centre tapped) and Bridge wave rectifier.(5 marks) 2 (a) design a single stage CE BJT amplifire using BC 147A to satisfy the following 20 specification :-
|A_v|?120, S_I ?8, V_cc=24V, R_L=10K ? f_L >10H_z, I_CQ=3mA.(10 marks) 2 (b) Estimate Ri and Ro of the designed amplifier. If Ri?3kilo ohms is the new specification then suggest suitable modification in the circuit. What sacrifice you have to make? Calculate it.(10 marks) 3 (a) Compare L ,C ,LC filter(5 marks) 3 (b) Design a full wave rectifier with LC filter which gives a DC output voltage of 10Volts at load current of 100milliampere .The allowable ripple factor is 0.02(10 marks) 3 (c) Calculate the V_GSQ, ID and V_DSQ of the following circuit. :- IMAGE(5 marks) 4 (a) Calculate the Ib,Ic,Vce of the following circuit. :- IMAGE (10 marks) 4 (b) Explain different biasing techniques used for EMOSFET(5 marks) 4 (c) Explain Base width modulation.(5 marks) 5 (a) Find Av, Avs, Zi, Zo, Ai of the given circuit :-IMAGE(10 marks) 5 (b) Find Zi, Zo, and output voltage if input voltage is 100mV of the given circuit :-IMAGE(10 marks) 6 (a) Draw a neat diagram of unbypassed CS amplifier,and derive the expression for voltage gain ,output impedence,input impedenceq(10 marks) 6 (b) find voltage gain,input impedence and output impedence of the circuit shown :- IMAGE(10 marks)

write short notes on the following

7 (a) VMOSFET construction and characteristic(5 marks) 7 (b) Voltage multiplier(5 marks) 7 (c) Photodiode operation and application(5 marks) 7 (d) Hybrid circuit of BJT(5 marks)