Electronic Devices and Circuits (B.Tech 3rd Semester, 2122)

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NOTE:- This paper consist of Three Sections. Section A is compulsory. Do any Four questions from Section B and any two questions from Section C

1 Explain the following:
(a) V-I characteristics of p-n doide.
(b) Advantages and disadvantages of JFET over BJT.
(c) Use of transistor as a switch.
(d) Principle of operation of audio oscillators.
(e) Principal of operation of photo diode
(f) Early effect in BJT.
(g) Function of heat sinks and regulated power supply.
(h) Biasing the FET.
(i) Distortion in amplifiers.
(j) Limitation of BJT operation at high frequency.

Section-B Marks:5 Each

2. Explin why transistor action cannot be achieved by connecting two back to back diodes.
3. Discuss the relative advantages and disadvantages of positive over negative feedback.
4. The transistor is connected as C-E amplifier and the h-parameters are hie=1100 Ω, hre=2.5X10-4, hfe=50, hoe=25
µ mho if RL and Rs resistances are both equal to 1 kΩ, find the various qains and input-output impedances.
5. What are the various biasing circuits? Draw their circuits and compare their performance.
6. Discuss any one ofd the following:
(a) Regulated Power Supply
(b) MOSFET NOT Logic Circuit.

Section-C Marks : 10 Each

7. (a) Draw the circuit of an R-C phase shift oscillator, explain its operation and evaluate its frequency of oscillation.
(b) Draw the circuit of a push pull amplifier and explain how it cancels even harmonics.
8. Draw the structure of n- channel JFET and MOSFET and explain their V-I characteristisc.
9. Write notes on any two of the following :
(a) Class-C power amplifier
(b) Photo-doide and Photo-transistor
(c) Regulated Power Supply