Download PTU B.Tech 2020 March ECE 3rd Sem BTEC 301 Analog Devices & Circuits Question Paper

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Roll No. Total No. of Pages : 02
Total No. of Questions : 09

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INSTRUCTIONS TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students have to attempt any TWO questions.

SECTION-A

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1. Write briefly :
   1. Why is zener diode used as voltage regulator?
   2. Give two advantages and disadvantages of FET over BJT.
   3. What do you understand by terms channel and drain in JFET?
   4. Why is it necessary to stabilize the operating point of a transistor amplifier?
   5. Give reasons why common emitter (CE) configuration is widely used in amplifier circuits.

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   6. What is reverse saturation current?
   7. What is tunnelling?
   8. Why is negative feedback employed in high gain amplifiers?
   9. List the two Barkhausen conditions required for sinusoidal oscillations to be sustained.
   10. What is crossover distortion? How can it be minimized?

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SECTION-B

What is P-N junction diode? How potential barrier is formed in a P-N junction diode?

Compare the characteristics of transistor amplifiers in the three possible configurations.

A class B push-pull amplifier must deliver 10 W of audio power to the output load :

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1. If the output transformer is 80% efficient, what is the minimum power drain on the power supply under optimum conditions and
2. What is the minimum average power dissipation rating required for each transistor?

Discuss the effects of negative feedback on gain, stability, and bandwidth.

Draw the hybrid model of a BJT and explain each component.

SECTION-C

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1. In a CE configuration, the collector supply voltage is 10 V. When a resistor RC =1 kO is connected in the collector circuit, the voltage drop across it is 0.5 V. For a = 0.98, determine the collector-emitter voltage and the base current.
2. Explain the operation of a tunnel diode: Draw its V-I characteristics and list the possible applications of the device.

Draw the circuit diagram of a Colpitt’s oscillator using transistor and explain its working principle. Also derive an expression for its frequency of oscillations.

1. The h parameters for a CE amplifier are h_ie =2600O, h_fe =100, h_re = 0.02x10^-4 and h_oe = 5x10^-6. Find h parameters for CC configuration.
2. What is the significance of stability factor in transistor operation?

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NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any page of Answer Sheet will lead to UMC against the Student.

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