Visvesvaraya Technological University (VTU) 2006 B.E Fifth Semester , .06 / 07 Operational Amplifier and Linear IC’s - Question Paper

Fifth Semester B.E. Degree exam , Dec.06 / Jan. 07
Electrical and Electronics Engineering
Operational Amplifier and Linear IC’s
Time:3 hrs] [Max.Marks:100
Note: 1. ans any 5 full ques..
2. Missing data may be suitably presumed.
3. Use of Opamp
data sheets is permitted.
1. a. describe the subsequent electrical parameters for an opamp:
(i) Input offset
voltage (ii) Input resistance
(iii) Output voltage swing (iv)CMRR.
(08 Marks)
b. What info does transfer curve reveal about opamp?
(04 Marks)
c. Sketch the circuit of a capacitorcoupled
voltage follower.
discuss the design procedure. (08 Marks)
2. a. describe : (i) Loop phase shift
(ii) Loopgain
(iii) Openloopgain
(iv) Closed loop gain for a feed back system. (08 Marks)
b. What is frequency compensation? discuss 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 every of the voltage comparators
Shown in fig.3 (a) are ± 15V. Sketch the output waveforms for every
When Vin is a 10 V peak sine wave. In every case show Vin and Vo
and tag voltage levels where switching occurs.
b. Sketch and discuss the working of sample and hold circuit. (06 Marks)
c. Name the opamp
circuit shown in fig.3 (c ) and discuss its working
and sketch its transfer curve.
4. a. Referring to fif.4 (a) sketch the output and transfer curve for the provided
opamp
clipper circuits. Take Vin = eight sinwt volts.
b. Sketch positive clamper circuit using opamp
and discuss 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 ranging from
+10V and 10V.
(i) obtain 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. describe an oscillator and elaborate the 2 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 needed 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 1st order low pass
Butterworth filter. (08 Marks)
b. What is a phase –locked loop? discuss 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. discuss its operation. (06 Marks)
b. Sketch the basic circuit of 723 voltage regulator and discuss the
regulator action. (10 Marks)
c. Differentiate small signal amplifiers and power amplifiers.

Earning:   Approval pending.