Calicut University 2006 B.Tech Electronics and Communications Engineering THIRD SEMESTER (ENGINEERING) , - Question Paper

THIRD SEMESTER B.Tech. (ENGINEERING) DEGREE EXAMINATION, DECEMBER 2006
EC 04 305—ELECTRONIC CIRCUITS
(2004 Admissions)
Time: 3 Hours Maximum: 100 Mark;
I. (a) discuss the function of a. transistor as an amplifier
(b) describe TJnity gain bandwidth'. What does it signify ?
(^Differentiate E MOSFET from D MOSFET.
(d) Differentiate FET from MOSFET.
•(e)". Derive an.expression-for Voltage gain of an Emitter follower.
.(f) Givean account on amplifier:gainfimction
(g) Draw thegeneral feedback structure and discuss.
(h) discuss the advantages and applications of crystal oscillators..
(8x5 = 40 marks)
II. (a) provide an account on the hybrid model and T model of transistor". (b) Draw the high frequency hybrid n model of a CE-B JT and-explain. Derive .expressions for all the parameters (15 marks-)

III. (a) (i) discuss the characteristics ofFET amplifiers and MOSFET amplifiers. (8 marks) (ii) discuss the biasing techniques in discrete circuits and in ICs. (7 marks)
$ .Or
(b) (i) Derive the relation among the FET parameters. (8 marks)
(ii) Draw an equivalent circuit CG FET amplifier and derive expressions for all the parameters.
(7 marks)
TV. (a) discuss in detail the use of open circuit and short circuit time constants in finding the cut-off frequencies.
(15 marks) Or
(b) Derive expressions for gain in low frequency, high frequency and mid-band ranges of a BJT amplifier. discuss the steps(15 marks



V. (a) (i) How does negative feedback decrease distortion in an amplifier ? (ii) State and discuss the stability condition interms of Bode plots.
Or
(b) Write short notes on :
one Factors that affect the frequency stability of an oscillator.
two Colpitts oscillator and its working
(8 marks) (7 marks)
(8 marks)
(7 marks)
[4 x 15 = 60 marks]

Earning:   Approval pending.