lic.qb.eee

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Department of EEE Linear Integrated Circuits and Applications

Dr. NAVALAR NEDUNCHEZHIYAN COLLEGE OF

ENGINEERING

Tholudur,Cuddalore (Dt)606 303.

QUESTIONBANK

SubjectCode/Subject:EE2254/ LINEAR INTEGRATED CIRCUITS AND APPLICATIONS

Name : S.RAJASRI Designation : ASSISTANT PROFESSOR

Dept: EEE Semester : IV

UNIT I

IC FABRICATIONIC classification, fundamental of monolithic IC technology, epitaxial growth, masking an

etching,diffusion of impurities. Realisation of monolithic ICs and packaging. Fabrication o

diodes,capacitance, resistance and FETs.

PARTA (1 MARK)

1. An ideal operational amplifier hasA) infinite output impedance B) zero input impedance

C) infinite bandwidth D) All of the above

2. Another name for a unity gain amplifier isA) difference amplifier B) comparatorC) single ended D) voltage follower

3. The open-loop voltage gain (Aol) of an op-amp is theA) external voltage gain B) internal voltage gain

C) most controlled parameter D) same asAcl

4. What is the output waveform?

A) sine wave B) square wave

C) sawtooth wave D) triangle wave

5. A series dissipative regulator is an example of aA) linear regulator B) switching regulator

C) shunt regulator D) dc-to-dc converter


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6. What is this circuit?

A) a low-pass filter B) a high-pass filter

C) a bandpass filter D) a band-stop filter

7. A non inverting closed-loop op-amp circuit generally has a gain factor:A) less than one B) greater than one

C) of zero D) equal to one

8. In order for an output to swing above and below a zero reference, the op-amp circuit requires:A) a resistive feedback network B) zero offset

C) a wide bandwidth D) a negative and positive supply

9. Op-amps used as high- and low-pass filter circuits employ which configuration?A) noninverting B) comparator

C) open-loop D) inverting

10.Decreasing the gain in the given circuit could be achieved by

A) reducing the amplitude of the input voltage

B) increasing the value of the feedback resistor

C) increasing the value of the input resistor

D) removing the feedback resistor

11.If ground is applied to the (+) terminal of an inverting op-amp, the () terminal will:A) not need an input resistor B) be virtual ground

C) have high reverse current D) not invert the signal

12.An astable multivibrator is also known as aA) one-shot multivibrator B) free-running multivibrator

C) bistable multivibrator D) monostable multivibrator

13.With negative feedback, the returning signalA) aids the input signal B) is proportional to output current

C) opposes the input signal D) is proportional to differential

voltage gain

14.What starts a free-running multivibrator?A) a trigger B) an input signal

C) an external circuit D) nothing

15.A portion of the output that provides circuit stabilization is considered to beA) negative feedback B) distortion


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C) open-loop D) positive feedback

16.How many leads does the TO-5 metal can package of an operational amplifier have?A) 8, 10, or 12 B) 6, 8, or 10

C) 8 or 14 D) 8 or 16

17.If a noninverting amplifier has an RINof 1000 ohms and an RFBof 2.5 kilohms, what is the RINvoltage when 1.42 mV is applied to the correct input?

A) 3.5 mV B) groundC) 1.42 mV D) 0.56 mV

18.Input impedance [Zin(I)] of an inverting amplifier is approximately equal toA)Ri B)Rf+Ri

C) D)Rf-Ri

19.The closed-loop voltage gain of an inverting amplifier equalsA) the ratio of the input resistance to the feedback resistance

B) the open-loop voltage gain

C) the feedback resistance divided by the input resistance

D) the input resistance

20.What is the cutoff frequency of this low-pass filter?

A) 4.8 kHz B) 3.8 kHz

C) 2.8 kHz D) 1.8 kHz

Answers:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

C D B D A D B D D C B B C D A A C A

PART-B (2 marks )

21.Mention the advantages of integrated circuits.*Miniaturisation and hence increased equipment density.

*Cost reduction due to batch processing.*Increased system reliability due to the elimination of soldered joints.

*Improved functional performance.

*Matched devices.

*Increased operating speeds.

*Reduction in power consumption.

22.Write down the various processes used to fabricate ICs using silicon planar technology.*Silicon wafer preparation.

* Epitaxial growth

*Oxidation.


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*Photolithography.

*Diffusion.

23.What is the purpose of oxidation?*SiO2 is an extremely hard protectivecoatingand is unaffected by almost all reagents.

*By selective etching of SiO2, diffusion of impurities through carefully defined windows can be accomplish

to fabricate various components.

24.Why aluminium is preferred for metallization?*It is a good conductor. *it is easy to deposit aluminium films using vacuum deposition.

makes good mechanical bonds with silicon. *It forms a low resistance contact.

25.What are the popular IC packages available?Metal can package. Dual-in-line package. Ceramic flat package.

26.Define an operational amplifier.[may/june-2012]An operational amplifier is a direct-coupled, high gain amplifier consisting of one or more differential amplifi

By properly selecting the external components, it can be used to perform a variety of mathematical operations.

27.Mention the characteristics of an ideal op-amp.* Open loop voltage gain is infinity. *Input impedance is infinity. *Output impedance

zero. *Bandwidth is infinity. *Zero offset.

28.Define input offset voltage. [APRIL-2011]A small voltage applied to the input terminals to make the output voltage as zero when the two inp

terminals are grounded is called input offset voltage.

29.Define input offset current. (OR) State the reasons for the offset currents at the input of the op-amThe difference between the bias currents at the input terminals of the op-amp is called as input off

current.

30.What are the applications of current sources? [NOV-2011]Transistor current sources are widely used in analog ICs both as biasing elements and as load devices

amplifier stages.31.Justify the reasons for using current sources in integrated circuits.

*superior insensitivity of circuit performance to power supply variations and temperature.

*more economical than resistors in terms of die area required to provide bias currents of small value.

*When used as load element, the high incremental resistance of current source results in high volt

gain at low supply voltages.

32.What is the advantage of widlar current source over constant current source? [may/june-2012]

Using constant current source output current of small magnitude(microamp range) is not attainable d

to the limitations in chip area. Widlar current source is useful for obtaining small output currents.Sensitivity

widlar current source is less compared to constant current source.

32.Mention the advantages of Wilson current source.*provides high output resistance.

*offers low sensitivity to transistor base currents.

33.Define sensitivity. .[may/june-2012]Sensitivity is defined as the percentage or fractional change in output current per percenta

or fractional change in power-supply voltage.


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PART-C (16 marks )

34.What is a current mirror? Explain the working of a wilder current source.(Nov -08),(Apr-08)35.What is slew rate? Discuss the methods of improving slew rate. (Nov -12)[APRIL-2011]36.What is an Active load ?Explain the CE amplifier with active load. (Nov -08)37.Explain pole zero compensation and frequency compensation in op-amp. (Nov -08,Nov-06)38.Define band gap reference ?Explain in detail about the reference circuit. (Apr-08)39.Briefly explain the method of using constant current bias for increasing CMRR in differential

amplifier.(Jun-12)

UNIT IICHARACTERISTICS OF OPAMP

Ideal OP-AMP characteristics, DC characteristics, AC characteristics, offset voltage and

current:voltage series feedback and shunt feedback amplifiers, differential amplifier; frequencyresponse of OP-AMP; Basic applications of op-ampsummer, differentiator and integrator.

PARTA (1 MARK)

40.All of the following are basic op-amp input modes of operation exceptA) inverting mode B) common-mode

C) double-ended D) single-ended

41.What is the output voltage?

A) 15 V B) 5 V

C)5 V D)15 V

42.A circuit whose output is proportional to the difference between the input signals is considered to which type of amplifier?

A) common-mode B) darlington

C) differential D) operational

43.With negative feedback, the returning signalA) is proportional to the output current

B) is proportional to the differential voltage gain

C) opposes the input signal

D) aids the input signal

44.What is the output waveform?


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C) phase comparator, bandpass filter, and demodulator

D) phase comparator, low-pass filter, and VCO

54.The major difference between ground and virtual ground is that virtual ground is only aA) voltage reference B) current reference

C) power reference D) difference reference

55.If an op-amp has one input grounded and the other input has a signal feed to it, then it is operatinas what?A) Common-mode B) Single-ended

C) Double-ended D) Noninverting mode

56.If the feedback/input resistor ratio of a feedback amplifier is 4.6 with 1.7 V applied to thenoninverting input, what is the output voltage value?

A) 7.82 V B) saturation

C) cutoff D) 9.52 V

57.The Schmitt trigger is a two-state device that is used forA) pulse shaping B) peak detection

C) input noise rejection D) filtering

58.When a capacitor is used in place of a resistor in an op-amp network, its placement determinesA) open- or closed-loop gain B) integration or differentiation

C) saturation or cutoff D) addition or subtraction

59.What value of input resistance is needed in the given circuit to produce the given output voltage?

A) 50 B) 4 kC) 4.08 k D) 5 k

Answers:

41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

A C C C A A B C D A D D C D A B D A

PART-B (2 marks )

60.Mention some of the linear applications of opamps :Adder, subtractor, voltage

to- current converter, current to- voltage converters, instrumentation amplifier, analog computation ,pow

amplifier, etc are some of the linear op-amp circuits.

61.Mention some of the nonlinear applications of op-amps:-Rectifier, peak detector, clipper, clamper, sample and hold circuit, log amplifier, anti

log amplifier, multiplier are some of the nonlinear op-amp circuits.

62.What are the areas of application of non-linear op- amp circuits? [NOV-2011]Industrial instrumentation


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Communication

Signal processing

63.What is the need for an instrumentation amplifier? .[may/june-2012]In a number of industrial and consumer applications, the measurement of physical quantities is usually done w

the help of transducers.

64.What do you mean by a precision diode?The major limitation of ordinary diode is that it cannot rectify voltages below the cut in voltage

the diode. A circuit designed by placing a diode in the feedback loop of an opamp is called the precision dio

and it is capable of rectifying input signals of the order of millivolt.

65.Write down the applications of precision diode.Half - wave rectifier

Full - Wave rectifier

Peakvalue detector

Clipper

Clamper

66.List the applications of Log amplifiers: [APRIL-2011]Analog computation may require functions such as lnx, log x, sin hx etc. These functions can be performed

log amplifiers Log amplifier can perform direct dB display on digital voltmeter and spectrum analyzer L

amplifier can be used to compress the dynamic range of a signal

67.What are the limitations of the basic differentiator circuit?At high frequency, a differentiator may become unstable and break into oscillations.

68.What are the applications of comparator?Zero crossing detector

Window detector

Time marker generator

Phase detector

69.What is a Schmitt trigger?Schmitt trigger is a regenerative comparator. It converts sinusoidal input into a square wave output. T

output of Schmitt trigger swings between upper and lower threshold voltages, which are the referen

voltages of the input waveform.

70.What is a multivibrator?Multivibrators are a group of regenerative circuits that are used extensively in timing applications. I

a wave shaping circuit which gives symmetric or asymmetric square output. It has two states either stablequasi- stable depending on the type of multivibrator.

71.What do you mean by monostable multivibrator? .[may/june-2012]Monostable multivibrator is one which generates a single pulse of specified duration in response to e

external trigger signal. It has only one stable state. Application of a trigger causes a change to the quasi-sta

state.An external trigger signal generated due to charging and discharging of the capacitor produces the transit

to the original stable state.

PART-C (16 marks )

72.Explain the operation of a Schmitt trigger circuit (Nov-08)[APRIL-2011]73.Explain the log and anti log amplifier (Nov-08)


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74.Design a second order low pass filter (Nov-08)75.Explain the working of full precision rectifier (Nov-08)76.(i)Design a differentiator to differentiate an input signal that varies in frequency from 10Hz to

about 1Khz (Apr-08)

(ii)If a sine wave of 1v peak at 1000Hz is applied to the differentiator , Draw its output

waveform

(iii)Give the basic differentiator frequency response .[may/june-2012]77.With circuit diagram discuss the following applications of op-amp(Dec-03)

(i) Voltage to current converter

(ii)Precision rectifier

78.Design a Schmitt trigger for UTP =0.5v and LTP=-0.5V (Dec-04)

UNIT III

APPLICATIONS OF OPAMP

Instrumentation amplifier, first and second order active filters, V/I & I/V converterscomparators, multivibrators, waveform generators, clippers, clampers, peak detector, S/Hcircuit, D/A converter (R-2R ladder and weighted resistor types), A/D converter - Dual slope

successive approximation and flash types.

PARTA (1 MARK)

79.The common-mode voltage gain isA) smaller than differential voltage gain B) equal to voltage gain

C) greater than differential voltage gain D) None of the above

80.How many logic states does an S-R flip-flop have?A) 2 B) 3C) 4 D) 5

81.An output that is proportional to the addition of two or more inputs is from which type ofamplifier?

A) differentiator B) difference

C) summing D) analog subtractor

82.In a PLL, to obtain lock, the signal frequency mustA) come within the lock range B) be less than the capture frequency

C) come within the capture range D) be greater than the capture

frequency

83.An ideal amplifier should haveA) high input current B) zero offset

C) high output impedance D) moderate gain

84.A differential amplifier has a common-mode gain of 0.2 and a common-mode rejection ratio of 32What would the output voltage be if the single-ended input voltage was 7 mV rms?

A) 1.4 mV rms B) 650 mV rms

C) 4.55 V rms D) 0.455 V rms

85.The magnitude of closed-loop voltage gain (Acl) of an inverting amplifier equalsA) the ratio of the input resistance to the feedback resistance


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B) the open-loop voltage gainAol

C) the feedback resistance divided by the input resistance

D) the input resistance

86.What is the difference between common-mode and differential-mode input signals?A) phase relationship B) voltage

C) current D) apparent power

87.A circuit that uses an amplifier with passive filter elements is called a(n)A) relaxation oscillator B) signal generator

C) differential amplifier D) active filter

88.Calculate the output voltage for this circuit when V1= 2.5 V and V2= 2.25 V

A)5.25 V B) 2.5 V

C) 2.25 V D) 5.25 V

89.When using an OTA in a Schmitt-trigger configuration, the trigger points are controlled byA) theIout B) theIBIAS

C) the Vout D) bothIoutandIBIAS

90.The primary function of the oscillator in an isolation amplifier is toA) convert dc to high-frequency ac B) convert dc to low-frequency ac

C) rectify high-frequency ac to dc D) produce dual-polarity dc voltages

for the input to the demodulator

91.An instrumentation amplifier has a highA) output impedance B) power gain

C) CMRR D) supply voltage

92.Circuits that shift the dc level of a signal are calledA) limiters B) clampers

C) peak detectors D) dc converters

93.In the classic three-op-amp instrumentation amplifier, the differential voltage gain is usuallyproduced by the

A) first stage B) second stage

C) mismatched resistors D) output op-amp94.What is the level of the output voltage of a ladder-network conversion?

A) The analog output voltage proportional to the digital input voltage

B) The digital output voltage proportional to the linear input voltage

C) A fixed digital value Vref

D) A fixed analog value Vref

95.Which of the following is not a linear/digital IC?A) Phase-locked loop B) Voltage-controlled oscillator

C) Passive filter D) Comparator

96.A 339 IC is an example of a fourteen-pin DIP that can be made to function as a ________.


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A) comparator B) 555 timer

C) D to A converter D) ladder network

97.What is the minimum number of conversions per second of a clock rate of 1 MHz operating a 10-stage counter in an ADC?

A) 1000 B) 976

C) 769 D) 697

98.Which of the following is (are) the results of improvements built into a comparator IC?A) Faster switching between the two output levels B) Noise immunity

C) Outputs capable of directly driving a variety of loads D)All of the above

Answers:

80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97

A C C C B C C A D D D A C B A A C A

PART-B (2 marks )

99.Mention some areas where PLL is widely used.*Radar synchronisation *satellite communication systems *air borne navigational syste

*FM communication systems *Computers.

100.List the basic building blocks of PLL*Phase detector/comparator *Low pass filter *Error amplifier *Voltage control

oscillator

101. What are the three stages through which PLL operates?[APRIL-2011]*Free running *Capture *Locked/ tracking102. Define lock-in range of a PLL

The range of frequencies over which the PLL can maintain lock with the incoming signal is called the lo

in range or tracking range.It is expressed as a percentage of the VCO free running frequency.

103. Give the classification of phase detector*Analog phase detector *Digital phase detector

104. What is a switch type phase detector? .[may/june-2012]An electronic switch is opened and closed by signal coming from VCO and the input signal is chopped a

repetition rate determined by the VCO frequency.This type of phase detector is called a half wave detector sin

the phase information for only one half of the input signal is detected and averaged.

105. What are the problems associated with switch type phase detector?*The output voltage Ve is proportional to the input signal amplitude.This is undesirable because it makes ph

detector gain and loop gain dependent on the input signal amplitude.

106. What is a multivibrator?Multivibrators are a group of regenerative circuits that are used extensively in timing applications. It is a w

shaping circuit which gives symmetric or asymmetric square output. It has two states either stable or quasi- sta

depending on the type of multivibrator.

107.What do you mean by monostable multivibrator?[APRIL-2001]


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Monostable multivibrator is one which generates a single pulse of specified duration in response to e

external trigger signal. It has only one stable state. Application of a trigger causes a change to the quasi-sta

state.An external trigger signal generated due to charging and discharging of the capacitor produces the transit

to the original stable state.

108.Give the classification of tuned amplifier(i) Small signal tuned amplifier

*Single tuned *Double tuned *Stagger tuned(ii) Large signal tuned amplifier.

PART-C (16 marks )

109. Draw a neat sketch showing a second order OTA(operational Tran conductance amplifier) bafilter and derive an expression for its Transfer function(Dec-03)[APRIL-2011]

110.Explain how the operations of division can be carried out using a multiplier IC(Dec-04)111.Explain the working of a Four quadrant multiplier(May-05)112.With circuit diagram describe the working of Gilbert multiplier cell. Explain how a Frequen

doubler can be realized using this cell.(Jun-06)

113.Explain the working of a general purpose voltage controlled oscillator(May-03)114.Discuss the Working principles of Frequency synthesizer(May-03)115.Explain the working of PLL.Explain in detail FSK demodulation using TLL(May-12)

.

UNIT IV

SPECIAL ICs

555 Timer circuit Functional block, characteristics & applications; 566-voltage controlledoscillator circuit; 565-phase lock loop circuit functioning and applications, Analog multiplier

ICs.PARTA (1 MARK)

116.What is the first phase of the dual-slope method of conversion?A) Connecting the analog voltage to the integrator for a fixed time

B) Setting the counter to zero

C) Connecting the integrator to a reference voltage

D) All of the above

117.What is the maximum conversion time of a clock rate of 1 MHz operating a 10-stage counter in a

ADC?

A) 1.024 s B) 102.3 ms

C) 10.24 ms D) 1.024 ms

118. On which of the following does the conversion depend in ladder-network conversion?A) Comparator B) Control logic

C) Digital counter D) Clock

119.The voltage-controlled oscillator is a subset of the "test bench" function generatorA) True B) False

120.Which application best describes this 555 timer circuit?


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A) Monostable multivibrator B) Astable multivibrator

C) Bistable multivibrator D) Free-running multivibrator

121. Which of the following applications include a phase-locked loop (PLL) circuit?A) Modems B) Am decoders

C) Tracking filters D) All of the above

122.Determine the free-running frequency when R3is set to 2.5 k .

A) 19.7 kHz B) 32.5 kHz

C) 116.39 kHz D) 212.9 kHz

123. What is the function of a ladder network?A) Changing an analog signal to a digital B) Changing a linear signal to a digital

C) Changing a digital signal to an analog D) None of the above

124. Which of the slope intervals of the integrator does the counter in the analog-to-digital converter(ADC) operate?

A) Positive B) Negative

C) Both positive and negative D) Neither positive nor negative

125.A 311 IC is an example of an eight-pin DIP that can be made to function as a ________.A) comparator B) 555 timer


126. What is (are) the level(s) of the input voltage to a ladder-network conversion?A) 0 B) Vref

C) 0 V or Vref D) None of the above

127.At which of the following period(s) is the counter advanced (incremented) in dual-slopeconversion?A) During the charging of the capacitor B) During the discharging of the capacitor

C) During both the charging and discharging D) None of the above

128. How many Vcc connections does the 565 PLL use?A) 0 B) 1

C) 2 D) 3

129. What is (are) the input(s) to the comparator in the ladder-network conversion of an ADC?A) Staircase voltage B) Analog input voltage

C) Both staircase and analog input voltage D) None of the above

130.This circuit is an example of a ________.


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A) comparator B) 555 timer


131. Which of the following best describes limitations for the 566 VCO?A) 2K R1 20K B) 0.75V+ VC V+

C) fo< 1 MHz D) All of the above

132.How many comparators does a 339 IC contain?A) 4 B) 3

C) 2 D) 1

133. When is the counter set to zero in the dual-slope method of conversion?A) Prior to the charging of the capacitor B) While the capacitor is being charged

C) At the end of the charging of the capacitorD) During the discharging of the capacitor

134.The 555 timer IC is made up of a combination of linear comparators and digital flip-flopsA) True B) False135.Which of the following devices is (are) a component of a digital-to-analog converter (DAC)?

A) Integrator B) Comparator

C) Digital counter D) All of the above

Answers:

117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134

A D A A A D C C C A C B C C D D A C

PART-B (2 marks )

136.List the broad classification of ADCs.1. Direct type ADC. 2. Integrating type ADC.

137. List out the direct type ADCs.1. Flash (comparator) type converter 2. Counter type converter 3. Tracking or servo converter 4. Success

approximation type converter

138. List out some integrating type converters.1. Charge balancing ADC 2. Dual slope ADC

139. What is integrating type converter? .[may/june-2012]An ADC converter that perform conversion in an indirect manner by first changing the analog I/P signal t

linear function of time or frequency and then to a digital code is known as integrating type A/D converter.

140. Explain in brief the principle of operation of successive Approximation ADC. The circuit of successive approximation ADC consists of a successive approximation register (SAR), to find

required value of each bit by trial & error.With the arrival of START command, SAR sets the MSB bit to 1. T

O/P is converted into an analog signal & it is compared with I/P signal. This O/P is low or High. This proc

continues until all bits are checked.

141. What are the main advantages of integrating type ADCs?i. The integrating type of ADCs do not need a sample/Hold circuit at the input.

ii. It is possible to transmit frequency even in noisy environment or in an isolated form.

142. Where are the successive approximation type ADCs used?


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The Successive approximation ADCs are used in applications such as data loggers & instrumentation wh

conversion speed is important.

143. What is the main drawback of a dual-slop ADC?The dual slope ADC has long conversion time. This is the main drawback of dual slope ADC.

144. State the advantages of dual slope ADC: [APRIL-2011]It provides excellent noise rejection of ac signals whose periods are integral multiples of the integration time T.

145. Define conversion time. .[may/june-2012]It is defined as the total time required to convert an analog signal into its digital output. It depends on

conversion technique used & the propagation delay of circuit components.

146. Define accuracy of converter.Absolute accuracy:

It is the maximum deviation between the actual converter output & the ideal converter output.

Relative accuracy:

It is the maximum deviation after gain & offset errors have been removed. The accuracy of a converter is a

specified in form of LSB increments or % of full scale voltage.

147. What is settling time? [APRIL-2011]It represents the time it takes for the output to settle within a specified

band LSB of its final value following a code change at the input (usually a full scale change). It depends up

the switching time of the logic circuitry due to internal parasitic capacitance & inductances. Settling time ran

from 100ns. 10s depending on word length & type circuit used.

148. Explain in brief stability of a converter:The performance of converter changes with temperature age & power supply variation . So all the relev

parameters such as offset, gain, linearity error & monotonicity must be specified over the full temperature

power supply ranges to have better stability performances.

149. What is meant by linearity?The linearity of an ADC/DAC is an important measure of its accuracy & tells us how close the converter outputo its ideal transfer characteristics. The linearity error is usually expressed as a fraction of LSB increment

percentage of full-scale voltage. A good converter exhibits a linearity error of less than LSB.

150. What is monotonic DAC?A monotonic DAC is one whose analog output increases for an increase in digital input.

PART-C (16 marks )

151. Explain the working of a Weighted resistor D/A converter(May-03)152. Explain successive approximation A/D converter(May-03)153. Explain the working of a dual slope A/D converter(May-04)[APRIL-2011]154. Explain the working of a Voltage to Time converter(May-04)155. Explain the working of a counter type A/D converter and state its important feature(Dec-04)156. Explain the working of a Voltage to Frequency converter(May-05)157. Explain the working of a high speed sample and hold circuit(May-05)

UNIT V

APPLICATION ICs

IC voltage regulators - LM317, 723 regulators, switching regulator, MA 7840, LM 380 powe


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amplifier, ICL 8038 function generator IC, isolation amplifiers, opto coupler, opto

electronicICs.

PARTA (1 MARK)

158.Which of the following circuits is (are) linear/digital ICs?A) Comparators B) Timers

C) Voltage-controlled oscillators D) All of the above

159. Which of the following best describes the output of a 566 voltage-controlled oscillator?A) Square-wave B) Triangular-wave

C) Both square- and triangular-wave D) None of the above

160. What is the voltage resolution of an 8-stage ladder network?A) Vref/128 B) Vref/256

C) Vref/512 D) Vref/1024

161. The timing components for a PLL are 15 k and 220 pF. Calculate the free-running frequency.A) 90.91 kHz B) 136.36 kHzC) 156.1 kHz D) 181.8 kHz

162.Which of the following frequencies is associated with the 565 frequency-shift keyed decoder?A) 1070 Hz B) 1270 Hz

C) Both 1070 Hz and 1270 Hz D) None of the above

163. The voltage gain of a basic instrumentation amplifier is set by a(n)A) diode. B) capacitor

C) resistor D) inductor

164. A basic ________ amplifier is formed by three op-amps and seven resistorsA) instrumentation B) isolation

C) log D) antilog

165. Instrumentation amplifiers are normally used to measureA) small differential signal voltages

B) signals superimposed on a common-mode voltage often much larger than the signal voltage

C) both of the above

D) none of the above

166. A(n) ________ amplifier is a differential voltage-gain device that amplifies the difference betweethe voltages existing at its two input terminals

A) instrumentation B) isolation

C) operational transconductance D) log

167. The main purpose of an instrumentation amplifier is to amplify ________ signals that are ridingon ________ common-mode voltages

A) small, small B) small, large

C) large, small D) large, large

168.A log amplifier may use the ________ junction of a BJT in the feedback loopA) base-collector B) base-emitter

C) emitter-collector D) emitter-ground

169.A current-to-voltage converter produces aA) constant output voltage for a variable input current


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B) variable output voltage for a constant input current

C) proportional output voltage for a variable input current

D) proportional output current for a variable input voltage

170. A log amplifier has ________ in the feedback loopA) a diode B) a BJT

C) a resistor D) either a diode or a BJT

171.What is (are) the principal area(s) of application for isolation amplifiers?A) medical B) power plant

C) automation D) all of the above

172. A constant-current source delivers a load current thatA) remains constant when the load resistance changes B) varies with load resistance

C) varies inversely with load resistance D) varies inversely with input voltage

173. The operational transconductance amplifier (OTA) is primarily a ________ -to- ________amplifier

A) current, voltage B) voltage, current

C) current, resistance D) resistance, current

174. The main difference between the isolation amplifier and an instrumentation amplifier isA) an instrumentation amplifier has an input stage.

B) an instrumentation amplifier has an output stage.

C) an instrumentation amplifier has a differential stage

D) the input, output, and power supply stages of an isolation amplifier are all electrically isolated from

each other

175. An antilog amplifier has a ________ in series with the input.A) BJT B) diode

C) diode or BJT D) resistor

176.The process known as signal compression is used with a(n) ____ amplifier.

A) log B) antilog

C) instrumentation D) isolation

177.Transconductance is the ratio of the outputA) current to the input voltage B) current to the input current

C) voltage to the input voltage D) voltage to the input current

59 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177

C B A C C A C A B B C D D A B D C A

PART-B (2 marks)

178. Mention some applications of 555 timer:*Oscillator *pulse generator *ramp and square wave generator *mono-shot multivibrator

*burglar alarm *traffic light control.

179. List the applications of 555 timer in monostable mode of operation:*missing pulse detector *Linear ramp generator *Frequency divider *Pulse width modulati

180. List the applications of 555 timer in Astable mode of operation:*FSK generator *Pulse-position modulator

181. What is a voltage regulator?A voltage regulator is an electronic circuit that provides a stable dc voltage independent of the load curre

temperature, and ac line voltage variations.


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182. Give the classification of voltage regulators:*Series / Linear regulators *Switching regulators.

183. What is a switching regulator?Switching regulators are those which operate the power transistor as a high frequency on/off switch, so t

the power transistor does not conduct current continously.This gives improved efficiency over series regulators

184. What are the advantages of IC voltage regulators?*low cost *high reliability *reduction in size *excellent performance

185. Give some examples of monolithic IC voltage regulators: [NOV-2011]78XX series fixed output, positive voltage regulators

79XX series fixed output, negative voltage regulators

723 general purpose regulator.

186. Define load regulation. [APRIL-2011]Load regulation is defined as the change in output voltage for a change in load current. It is expressed

millivolts or as a percentage of the output voltage.

187. What is meant by current limiting? .[may/june-2012]Current limiting refers to the ability of a regulator to prevent the load current from increasing above a

preset value.

188. Give the drawbacks of linear regulators:*The input step down transformer is bulky and expensive because of low line frequency.

*Because of low line frequency,large values of filter capacitors are required to decrease the ripple.

*Efficiency is reduced due to the continous power dissipation by the transistor as it operates in the linear

region.

189. Mention the advantages of opto-couplers: [April-2011]*Better isolation between the two stages. *Impedance problem between the stages is eliminated.

*Wide frequency response. *Easily interfaced with digital circuit. *Compact and light weight.

*Problems such as noise, transients, contact bounce,.. are eliminated.

190. What is an isolation amplifier?An isolation amplifier is an amplifier that offers electrical isolation between its input and output termina

191. Give the classification of tuned amplifier:(i) Small signal tuned amplifier

*Single tuned *Double tuned *Stagger tuned

(ii) Large signal tuned amplifier.

PART-C (16-marks)

192. Explain the operations of Mono stable Multivibrator using 555 timer(May-03).193. Explain about power amplifier and video amplifier(May-12)194. Draw and Explain the functional block diagram of the LM-317 three terminal adjustable

regulator(Dec-03)

195. Explain the working of a timer circuit (May-04)196. Design an Astable Multivibrator using 555 Timer to produce 1Khz square wave form for duty

cycle=0.50(Dec-04)

197. Draw an explain the Functional block diagram of a 723 Regulator (Dec-04)198. Explain the working of Voltage regulator (May-05)199. Explain the working of Frequency to voltage converter(Dec-05)


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