Electronic Devices - May 2014

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. 1 (a) What is Non-ideal effects in BJT and hence explain Base width modulation in brief(5 marks) 1 (b) Justify how phototransistor is more practical than photo diode(5 marks) 1 (c) Explain in brief TWO Terminal MOS structure(5 marks) 1 (d) Explain construction and characteristics of UJT (5 marks) 2 (a) Explain concepts, construction, characteristics and working of Gunn diode(10 marks) 2 (b) Explain basic principle of operation of BJT with the help of construction, minority carrier distribution and energy band diagrams(10 marks) 3 (a) Explain structure and operation of MOSFET considering different cases of threshold voltage V_T(10 marks) 3 (b) An abrupt PN junction has dopant concentrations of
Na=2×10¹⁶ cm^-3 and Nd=2 ×10¹⁵ cm^-3 at T=300 K
Calculate :- (a) Vbi
(ii) W at V_R=0 and V_R=8V
(iii) E maximum at V_R=0 and V_R=8V(10 marks) 4 (a) What is photovoltaic effect. Explain in detail Solar Cell with working, characteristics and practical applications(10 marks) 4 (b) For an n-channel MOS transistor with
?n=600 cm²/V.S Cox=7×10^-18 F/cm²,
W=20?m, L=2?m and VTO=1.0V
Examine the relationship between the Drain current and terminal voltages.(10 marks) 5 (a) Explain construction, working and characteristics of TRIAC & DIAC (10 marks) 5 (b) Explain schottky-barrier diode with the help of energy band diagram(10 marks) 6 (a) What is HBT, explain construction and energy band diagram of HBT(10 marks) 6 (b) Explain difference between N-channel and P-channel JFET, also explain characteristics (Drain and Transfer) for N-channel JFET(10 marks)