Operational Amplifier and Linear IC’s Question paper 2006 Visvesvaraya Technological University Fifth Semester B.E. Degree Examination ,

2006 Visvesvaraya Technological University Fifth Semester B.E. Degree Examination , Dec.06 / Jan. 07Fifth Semester B.E. Degree Examination , Dec.06 / Jan. 07
Electrical and Electronics Engineering
Operational Amplifier and Linear IC’s
Time:3 hrs Max.Marks:100
Note: 1. Answer any Five full questions.
2. Missing data may be suitably assumed.
3. Use of Opamp
data sheets is permitted.

1. a. Define the following electrical parameters for an opamp:
(i) Input offset
voltage (ii) Input resistance
(iii) Output voltage swing (iv)CMRR.
(08 Marks)
b. What information does transfer curve reveal about opamp?
(04 Marks)
c. Sketch the circuit of a capacitorcoupled
voltage follower.
Explain the design procedure. (08 Marks)
2. a. Define : (i) Loop phase shift
(ii) Loopgain
(iii) Openloopgain
(iv) Closed loop gain for a feed back system. (08 Marks)
b. What is frequency compensation? Explain phase lag or phase
lead compensation method. (08 Marks)
c. List the precautions that should be observed for opamp
circuit stability. (04 Marks)
3. a. The maximum output voltages of each of the voltage comparators
Shown in fig.3 (a) are ± 15V. Sketch the output waveforms for each
When Vin is a 10 V peak sine wave. In each case show Vin and Vo
and label voltage levels where switching occurs.
b. Sketch and explain the working of sample and hold circuit. (06 Marks)
c. Name the opamp
circuit shown in fig.3 (c ) and explain its working
and sketch its transfer curve.
4. a. Referring to fif.4 (a) sketch the output and transfer curve for the given
opamp
clipper circuits. Take Vin = 8 sinwt volts.
b. Sketch positive clamper circuit using opamp
and explain its operation (08 Marks)
5. a. Sketch the circuitry of an astable multivibrator using opamp
and sketch
the relevant waveforms (10 Marks)
b. The output of the Schmitt trigger shown in fig.5(b) switches between
+10V and 10V.
(i) Find the lower and upper trigger levels
(ii) Fine hysterisis.
(iii) Sketch the hysterisis loop.
(iv) Sketch the output when Vin is a 10 V peak sine wave
6. a. Define an oscillator and what are the two requirements for oscillation. (03 Marks)
b. Sketch Wein Bridge oscillator circuit and derive expression for the :
(i) Frequency of the waveform generated and
(ii) Gain required for sustaining oscillations. (12 Marks)
c. Sketch the output of an integrator shown in fig.6 (c ) on the graph sheet.
Take R1= 1K, C = 0.1 mF.
7. a. Derive expression for gain and phase angle of first order low pass
Butterworth filter. (08 Marks)
b. What is a phase –locked loop? Explain the working of building blocks
of PLL. (08 Marks)
c. What is a dc voltage regulator? Define:
i) line regulation (ii) load regulation (04 Marks)
8. a. Sketch the circuit of a voltage follower regulator. Explain its operation. (06 Marks)
b. Sketch the basic circuit of 723 voltage regulator and explain the
regulator action. (10 Marks)
c. Differentiate small signal amplifiers and power amplifiers.

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