JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year 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 the term diffusion capacitance CD of a PN diode.
Answer
Diffusion capacitance (CD) is the capacitance that arises in a forward-biased PN junction diode due to the storage of minority charge carriers near the junction. It represents the rate of change of the stored minority carrier charge with respect to the applied forward voltage, defined by the formula:
It is significantly larger than transition capacitance and is dominant in forward-biased conditions.
Define the term Transformer Utilization Factor (TUF) and PIV.
Answer
Transformer Utilization Factor (TUF) is defined as the ratio of the DC power delivered to the load to the AC power rating of the transformer secondary winding. It indicates how effectively the transformer is being utilized in a rectifier circuit. A higher TUF value signifies that the transformer is being used more efficiently.
Peak Inverse Voltage (PIV) is the maximum voltage that a diode must withstand in the reverse-biased direction without breaking down. It is a critical parameter in rectifier design, as the diode must be rated to handle this peak voltage to prevent damage during the negative half-cycle of the input AC signal.
Define stability factor.
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List the factors causing thermal runaway.
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State De Morgans Laws.
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Differentiate between J-FET and MOSFET.
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Determine the complement of the AB(BC′+BC)(AC′+AB).
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What do you mean by K-map? Mention its advantages.
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What is a sequential logic circuit?
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Mention the differences between RAM and ROM.
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Part B
Explain the construction and working of photodiode.
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What is a clipping circuit? Explain the operation of a Positive clipper with suitable diagrams.
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Explain the working of a full wave bridge rectifier with circuit diagram and input output waveforms.
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Explain the working of a Half wave rectifier with Capacitor filter and derive the expression for its ripple factor.
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What is the Thermal Runway? How can it be avoided?
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Explain the input and output characteristics of a transistor in CE configuration.
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Draw the circuit diagram of a RC coupled amplifier and explain its operation.
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Compare the performance of a transistor in all the three configurations.
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Explain the construction and working of a depletion type MOSFET and compare it with enhancement type.
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With suitable diagrams, explain the operation of a basic logic gates in RTL and DCTL logic.
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Define the function of a decoder. Design a 3 to 8 decoder, draw the circuit diagram, function table and explain the working of the decoder circuit.
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Simplify the following function and implement it with NAND gates only.
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Draw the circuit of JK Flip Flop using NAND gates and explain its operation.
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Construct a T-flip-flop and explain its operation with truth and transition tables.
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What is a shift register? Draw the block diagram and timing diagram of a shift register that shows the serial transfer of information from register A to register B.
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Compare latches and flip flops.
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