JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year ANALOG AND DIGITAL ELECTRONICS Previous Question Paper (April/May - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Define static and dynamic resistances of diode.
Answer
Static resistance (or DC resistance) is the ratio of the DC voltage across the diode to the DC current flowing through it at a specific operating point, defined as Rdc = V/I. Dynamic resistance (or AC resistance) is the reciprocal of the slope of the diode's V-I characteristic curve at a given operating point, defined as rac = ΔV/ΔI, representing the resistance offered by the diode to small changes in voltage or current.
Discuss about breakdown of a diode.
Answer
Diode breakdown occurs when a P-N junction is subjected to a high reverse bias voltage, causing a sudden increase in current. There are two primary mechanisms for this phenomenon:
- Zener Breakdown: Occurs in heavily doped diodes at low reverse voltages (typically below 5V). The high electric field across the narrow depletion region exerts a force on valence electrons, pulling them directly out of their covalent bonds, creating a large number of free charge carriers.
- Avalanche Breakdown: Occurs in lightly doped diodes at higher reverse voltages. As the electric field increases, minority carriers gain sufficient kinetic energy to collide with atoms, knocking off additional electrons through impact ionization. These new carriers then gain energy and cause further collisions, leading to a cumulative, self-sustaining avalanche of current.
Once the breakdown voltage is reached, the diode current increases rapidly while the voltage across the diode remains relatively constant, a property utilized in Zener voltage regulator circuits.
Define operating point and dc load line.
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What are the different current components in a transistor?
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Write short notes on applications of FET.
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Realize the basic AND gate using NAND gate only.
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What are don’t care conditions and an essential prime implicante?
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What are the applications of a multiplexer?
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List out difference between latch and flip-flop.
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Give the differences between RAM and ROM.
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Part B
Explain the effect of temperature on V-I characteristics of a diode.
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Explain the working of Tunnel diode with help of energy band diagrams and Draw its V-I Characteristics.
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Explain Full wave rectifier with neat circuit diagram and waveforms.
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Explain the construction and working principal of photo diode.
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Draw the circuit diagram of a transistor in CB configuration and explain the output characteristics with the help of different regions.
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Explain how Transistor acts as an Amplifier?
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Draw a Fixed bias circuit and explain its operation. Calculate the Stability factor S and S'?
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What are the compensation techniques used with respect to variations in VBE and ICO? Explain with the help of suitable circuits.
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Explain the principle of CS FET amplifier with the help of circuit diagram.
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Simplify the Boolean expression xy'z+x'y'z+w'xy+wx'y+wxy and realize it using basic gates.
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Explain the construction and principle of operation of Depletion type N-channel MOSFET.
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Explain the characteristics of CMOS logic family.
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Simplify the following function using K-map and implement using universal gates F=A'BC'D'+A'BC'D+AB'CD+AB'CD+AB'CD'+ABCD+A'B'C'D'
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Define magnitude comparator and Design a 2-bit comparator to compare two 2-bit numbers.
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Design a 4 bit binary parallel sub tractor and explain its operation in detail.
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Implement the following Boolean function using 8:1 multiplexer F(A,B,C.D) = Σm (0,1,2,5,7,8,9,14,15)
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Explain the operation of SR flip flop with the help of its truth table.
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Design and explain the operation of Bi-directional shift register.
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Convert T-flip-flop to JK- flip-flop.
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Explain the procedure of state minimization using the partition technique.
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