JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III Year PULSE AND DIGITAL CIRCUITS Previous Question Paper (May/June - 2019 - R13)
This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
Draw a series RL circuit, explain its operation and write the current voltage relationship.
Answer
A series RL circuit consists of a resistor R and an inductor L connected in series with an input voltage source. When a voltage is applied, the inductor opposes the change in current, leading to an exponential rise in current. The relationship is given by the differential equation: v(t) = i(t)R + L(di/dt).
Derive an expression for the output of a high-pass circuit excited by a ramp input.
Answer
For a high-pass RC circuit with a ramp input vi(t) = αt, the output is given by the convolution or the differential equation vo = RC(dvi/dt) for small RC. Solving the circuit equation vi = vR + vo where vR = RC(dvo/dt), we get vo(t) = αRC(1 - e-t/RC).
What is meant by clamping in wave shaping?
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Draw the circuit of a positive series clipper and explain.
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Explain the working of a diode as a switch.
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Explain the variation of saturation parameters of transistor with temperature.
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Write the difference between current time base generator and voltage time base generator.
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What are the general features of time base signal?
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Give the salient features of TTL Logic family.
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Draw the diagram of AND gate using diodes and explain.
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PART - B
Derive an expression for the rise time of the output of a low-pass circuit excited by a step input.
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Why RC circuits are commonly used compared to RL circuits? Elaborate.
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Explain the response of high pass RC circuit for square wave input with relevant waveforms. When this circuit acts as an differentiator?
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Write short notes on attenuators.
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State and prove clamping circuit theorem.
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What is the effect of diode characteristics on clamping voltage? Explain.
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Draw the basic circuit diagram of positive peak clamper circuit and explain its operation.
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What is meant by comparator? Explain the diode differentiator comparator.
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Explain the operation of linear bidirectional sampling gate using transistors.
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What is pedestal? What are the effects of it in sampling gates?
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Explain the principle of operation of sampling gates.
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Write the advantages and disadvantages of unidirectional and bidirectional diode sampling gates.
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Explain with the help of a neat circuit diagram the principle of operation of a monostable multivibrator, and derive an expression for pulse width.
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Define UTP and LTP in a Schmitt trigger.
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With the help of a neat circuit diagram and waveforms, explain the working of a transistor bootstrap time base generator.
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Write short notes on methods of linearity improvement in sweep circuits.
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Describe the sine wave frequency division with a sweep circuit.
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Compare sine wave synchronzation with pulse synchronization.
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Give a comparison of various logic families.
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Discuss the importance of synchronization and frequency division.
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