JNTU
JNTU B.Tech III PULSE AND DIGITAL CIRCUITS Previous Question Paper (May - 2018 - R13)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Part B consists of 5 Units. Answer any one full question from each unit.
PART - A
Define rise time and fall time.
Answer
Rise time (tr) is the time required for the output voltage to rise from 10% to 90% of its final steady-state value. Fall time (tf) is the time required for the output voltage to fall from 90% to 10% of its initial value.
Derive an expression for the output of a low-pass circuit excited by a ramp input.
Answer
For a low-pass RC circuit with input vi(t) = αt, the output vo(t) is governed by the differential equation vi = vo + RC(dvo/dt). Substituting vi = αt and solving using the Laplace transform or integrating factor method with zero initial conditions yields:
Write the applications of voltage comparator.
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Draw the circuit of negative peak clamper and explain.
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When does the transistor acts as a switch?
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Draw the piecewise linear diode characteristics.
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What are the different types of multivibrator circuits?
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Draw the bistable multivibrator circuit using transistors. Give its applications.
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Explain the principle of synchronization.
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Draw the diagram of OR gate using diodes and explain.
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PART - B
Explain the response of low pass RC circuit for square wave input with relevant waveforms. When this circuit acts as an integrator?
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What is a ringing circuit?
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Derive an expression for the output of a high-pass circuit excited by a square input.
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Derive the expression for percentage tilt for a square wave output of RC high pass circuit.
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Give the circuits of different types of shunt clippers and explain their operation with the help of their transfer characteristics.
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Write short notes on synchronized clamping.
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Explain the operation of a double diode clipper and sketch the output wave form for a sinusoidal input.
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Write short notes on transistor clippers.
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Explain in detail the junction diode switching times.
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Write short notes on four diode sampling gate.
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Why are sampling gates called linear gates?
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Compare the unidirectional and bi-directional sampling gates.
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Explain the significance of integrator in Miller sweep circuit.
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How a linearly varying current waveform can be generated from voltage time base generator? Explain.
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Explain with the help of a neat circuit diagram the principle of operation of an astable multivibrator, and derive an expression for its time period.
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Draw the Schmitt trigger circuit.
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Explain the method of synchronization of a sinusoidal oscillator with pulses.
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Compare the TTL and CMOS logic families.
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With the help of neat waveforms, explain frequency division with a sweep circuit.
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Explain the principle of synchronization in sweep circuits and describe how frequency division synchronization is done in astable relaxation circuits with help of neat diagram.
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