Analog Electronics - 1 - May 2014
Electronics & Telecomm. (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.
Solve any five :-
1 (a) Explain effect of temperature on characteristics of PN junction diode.(4 marks) 1 (b) Why LC oscillators are prefered for high frequency applications?(4 marks) 1 (c) Find RB and RC for the circuit shown to obtain VCE=5V and IC=2mA (4 marks) 1 (d) In n-channel MOSFET VDS=5V, VGS=5V, VBS=0, W=10 ?m, L=5 ?m k'n=100 mA/V2 and VTO=1V. Calculate its drain current for channel length modulation factor ? of 0 and 0.25 V-1(4 marks) 1 (e) Draw and explain small signal hybrid-Pi model of BJT including early effect.(4 marks) 1 (f) Differentiate between NJT and MOSFET(4 marks) 2 (a) Find ICQ and VCEQ for the circuit shown in figure 2a if ?=100 (10 marks) 2 (b) Draw and explain energy band diagram of MOS capacitor in accumulation, depletion and inversion region.(10 marks) 3 (a) Draw and explain working of transisterized Wien Bridge Oscillator(10 marks) 3 (b) The JFET shown in figure 3b has parameter IDSS=8mA and Vp=4V. Determine VG, IDSQ, VGSQ and VDSQ (10 marks) 4 (a) For the common gate circuit shown in figure 4s, the NMOS transistor parameters are VTN=1, kn=3 mA/V2 and ?=0 (i) Determine IDSQ and VDSQ (ii) Calculate gm and ro (iii) Find the small signal voltage gain Av= v0/v1. Assume Cc1 and Cc2 acts as short circuit for small-signal analysis (10 marks) 4 (b) The parameter of the transistor in the circuit shown in figure 4b are ?=100 and VA=100V. (i) Determine the voltages at base and emitter terminals (ii) Find Rc such that VCEQ=3.5V and (iii) Assuming CC and CE acts as short circuit determine small signal voltages gain Av= v0/vs (10 marks) 5 (a) Derive expression for voltage gain NMOS source follower cicuit(8 marks) 5 (b) For the common base amplifier shown in figure 5b, derive expression for voltage gain, current gain, input resistance and output resistance using hybrid-? model (12 marks)
Write short note on any three :-
6 (a) Series and shunt clippers(7 marks) 6 (b) Twin-T oscillator(7 marks) 6 (c) MOSFET operation(7 marks) 6 (d) Construction and operation of varactor diode.(7 marks)