0
1.9kviews
Electronic Devices and Circuits 2 Question Paper - Dec 18 - Electronics And Telecomm (Semester 4) - Mumbai University (MU)
1 Answer
0
30views

Electronic Devices and Circuits 2 - Dec 18

Electronics And Telecomm (Semester 4)

Total marks: 80
Total time: 3 Hours
INSTRUCTIONS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Draw neat diagrams wherever necessary.

Q1

a) Draw a neat labelled diagram of Enhancement type MOSFET and explain its operation.
(5 marks) 00

b) Explain RC coupled amplifier.
(5 marks) 00

c) What is Oscillator? Explain Basic Principle of an oscillator.
(5 marks) 00

d) Differentiate Class A, Class B and Class C power amplifiers.
(5 marks) 00

Q2

a) Design a two stage RC coupled CS-CE amplifier to meet following specifications: $A_v$ > 500, S<8, $R_i$ > 1 M$\Omega$, $V_{CC}$ = 6V.

Assume the following data: $\beta_{typ}$ = 290, $h_{ie}$ = 4.5k$\Omega$, $g_{mo}$ = 500$\mu \Omega$, $I_{DSS}$ = 7mA, $r_d$ = 50k$\Omega$, $V_P$ = -4V.

(15 marks) 00

b) For a 'n' stage cascaded amplifier, show that overall lower 3 dB cut-off frequency is $f_{LT}$ = $\frac{f_L}{(2^\frac{1}{n}-1)^\frac{1}{2}}$
(5 marks) 00

Q3

a) With the help of neat block diagram, derive expression for $R_{IF}$, $R_{OF}$, $G_{mF}$ for voltage series negative feedback amplifier. Give significance of the above mentioned parameters.
(10 marks) 00

b) Write short note on: Darlington pair amplifier
(10 marks) 00

Q4

a) Find the necessary condition for oscillations to occur and frequency of oscillations of Colpittis oscillator. Also, explain its working.
(10 marks) 00

b) Draw a neat diagram of direct coupled class A Amplifier and explain its working. Hence, find its efficiency.
(10 marks) 00

Q5

a) Determine input impedence, output impedence and voltage gain. and current gain for the given cascaded amplifier as shown in the figure below:
(10 marks) 00

b) Draw circuit diagram of cascode amplifier and explain in detail.
(10 marks) 00

Q6

a) State and explain different types of Biasing techniques for deplition type MOSFET
(8 marks) 00

b) Explain the concept of Heat sink in detail required for power amplifiers.

A Silicon power transistor is operated with a heat sink with $Q_{SA}$ = 1.2 C/W. the transistor is rated for 120W at 25 and has $Q_{JC}$ 0.5 C/W. The mounting insulation has $Q_{CS}$ = 0.5 C/W. What maxmimum power can be dissapted if the ambient temprature is 40 C and $T_{J(max)}$ = 200 C.

(7 marks) 00

c) Calculate frequency of Oscillation fpr harley oscillator if $L_1$ = $L_2$ = 1mH and C=0.2 $\mu F$
(5 marks) 00

Please log in to add an answer.