Linear Integrated Circuits

School of Engineering and Technology Electronics and Communication Department

LIC MCQ Unit 1

1. A transconductance amplifier is one which has

(a) Input is a current I and output is voltage V

(b) Input is voltage V and output is current I

(c) Input is voltage VI and output is voltage V0

(d) Input is current Iin and output is current I0

2. A transresistance amplifier is one which has

(a) Input is a current I and output is voltage V

(b) Input is voltage V and output is current I

(c) Input is voltage VI and output is voltage V0

(d) Input is current Iin and output is current I0

3. IC-741 op-amp has typical gain of in dB

(a) 110 dB

(b) 100 dB

(c) 106 dB

(d) 90 dB

4. Ideal terminal conditions of IC-op-amp are

(a) Vd = ∞, V0 = 0, iP = iN = currents drawn by inverting and non-inverting inputs. iP = iN = 0.

(b) Vd = 0, V0 = ∞, ip = iN = ∞

(c) Vd = 0, V0 = 0, iP = iN=0

(d) none of the above

5. The other name of voltage follower is

(a) differential amplifier

(b) inverting amplifier

(c) non-inverting amplifier

(d) unity gain amplifier

6. Find V0

(a) − Rf/R1 · V1

(b) − Rf/R1 · Vx − Rf/R2

(c) − Rf/R2V1

(d) none

Figure 1. Circuit Diagram for Q.6

7. An op-amp current to voltage converter is also called

(a) transconductance amplifier

(b) transimpedance amplifier

(c) transresistance amplifier


8. A VI op-amp converter is also called

(a) transconductance amplifier

(b) transresistance amplifier

(c) transimpedance amplifier


9. The differential mode and common mode voltage is defined as

(a) VDM = V2 − V1, VCM = V1 + V2/2

(b) VDM = V1 + V2/2, VCM = V2 − V1

(c) VDM = V1/2 = V2/2, VCM = V2 − V1/2


10. For a true difference amplifier, the following holds true:

(a) Acm → 0, CMRRdB → 0

(b) Acm → ∞, CMRRdB → ∞

(c) Acm → ∞, CMRRdB → 0

(d) Acm → 0, CMRRdB → ∞

11. An ideal op-amp should have

(a) Zero input impedance and output impedance

(b) Infinite input and output impedance

(c) Infinite input impedance and zero output impedance

(d) Zero input impedance and infinite output impedance

12. An ideal op-amp should have

(a) low gain at low frequencies

(b) low gain at low frequency and high gain at high frequencies

(c) high gain at low frequency and low gain at high frequencies

(d) high gain at all frequencies

13. The actual gain of an op-amp at dc is of the order

(a) 10 to 100

(b) 100 to 1000

(c) 100 to 100,000

(d) 1000,000 to 100,000,000

14. The ideal input impedance range of op-amp is

(a) 1 kΩ

(b) 10 kΩ to 106 mΩ

(c) 106 mΩ to 1012 mΩ

(d) none

15. Drift of amplifier means

(a) variation of gain with load

(b) variation of gain with frequency

(c) change in sensitivity due to variation in temperature


16. Which of the following amplifier compensates for drift?

(a) Low gain amplifier

(b) High gain amplifier

(c) DC amplifier

(d) Differential amplifier

17. In addition to reduction to drift, the advantage of a differential amplifier is

(a) mixing of two input voltages

(b) an output of either polarity

(c) rejection of common mode signal

(d) all of the above

18. An ideal amplifier should have

(a) infinite gain at all frequencies

(b) large bandwidth

(c) zero phase shift


19. An amplifier is an unstable condition when

(a) gain is low

(b) load is variable

(c) phase shift is 180°

(d) supply is rectified DC

20. Noise in op-amp due to

(a) pick up from main supply

(b) sparking in the circuit

(c) internal generation


21. Noise in op-amp can be reduced to

(a) shielding

(b) uselpf

(c) proper grounding


22. For the op-amp shown in Fig 2 the output will be

(a) − 2x

(b) − 5x

(c) − 12

(d) − 720 x

Fig. 2

23. For which values of Rf and Ri the output/input ratio of the amplifier shown in Fig.3, will be the least?

(a) Rf = 100 kΩ, Ri, = 10 kΩ

(b) Rf = 800 kΩ, Ri = 200 kΩ

(c) Rf = 1000 kΩ, Ri = 10 kΩ

(d) Rf = 10 kΩ, Ri = 1 kΩ

Fig.3

24. In the circuit shown below, the feedback factor will be

(a) 1/3

(b) 2/7

(c) 3/7

(d) 1/7

Fig.4

25. The circuit shown represents

(a) adder

(b) integrator

(c) differentiator

(d) subtractor

Fig.5


(a) differentiator

(b) adder

(c) multiplier

(d) sign reversal

Fig. 6


(a) DC voltage follower

(b) inverter

(c) logarithmic amplifier


Fig.7

28. An integrator is mostly preferred over differentiator because

(a) more stable

(b) less voltage drift

(c) less noise


29. A µA 741C op-amp is used in the circuit, the output voltage for the ideal op-amp will be

(a) − 5 V

(b) − 3 V

(c) − 2.5 V

(d) − 2 V

Fig. D.9

30. If a square wave is integrated by integrator using operational amplifier, the output is

(a) triangular wave

(b) ramp

(c) sine wave


31. Monolithic IC wafers are typically of

(a) 1/8 inch diameter

(b) 1/4 inch diameter

(c) 1 inch diameter

(d) 2 inch diameter

32. A good op-amp has

(a) very high bandwidth

(b) narrow bandwidth

(c) high selectivity


33. When an op-amp is operated in common mode fashion, CMRR should be

(a) zero

(b) infinitely high

(c) very small

(d) 5 dB

34. Which amplifier will be preferred for highest gain?

(a) darlington's pair

(b) operational amplifier

(c) cascade amplifier


35. Decibel is defined in terms of

(a) voltage ratio

(b) current ratio

(c) power ratio


36. A linear system can be described by

(a) state transition equation

(b) differential equation

(c) dynamic equation


37. At which of the following frequency, the gain of op-amp will be zero?

(a) β cut-off frequency

(b) α cut-off frequency

(c) unity gain cross over frequency

(d) gain cross over frequency

38. Silicon is preferred for semiconductor devices

(a) abundant availability

(b) easy formation of oxide layer

(c) hood mechanical strength


39. A monolithic circuit means

(a) circuit from single crystal

(b) circuit from more than one crystal

(c) uses double price of crystal to form a circuit


40. The standard package configurations of manufacturing IC.

(a) glass metal package

(b) ceramic flat package

(c) dual in line


41. The basic elements of op-amp is

(a) differential amplifier

(b) buffer, level translator

(c) output driver


42. For large CMRR, ACM should be

(a) as large as possible

(b) as small as possible

(c) zero

(d) level to Adm

43. MOSFET op-amp is preferred over BJT, FET because

(a) high input resistance 1012 Ω

(b) low input current, 1PA

(c) high slew rate, 10 V/µS

(d) all the above

44. DC character of op-amp are

(a) input bias and offset current

(b) input offset voltage

(c) thermal drift


45. AC characteristics of op-amp includes

(a) Frequency response

(b) slew rate

(c) both a and b


46. An ideal op-amp should have open loop gain

(a) around 90 dB constent over audio and Rf frequency

(b) less than 90 dB, varies on audio and Rf frequency

(c) 20 dB, constent audio and Rf frequency


47. The frequency response of op-amp includes

(a) magnitude character only

(b) phase character only

(c) both (a) and (b)


48. The slew rate for IC 741 is

(a) 0.5 V/µs

(b) 0.9 V/µs

(c) 0.8 V/µs

(d) 1 V/µs

49. Number of diodes required in half-wave rectifier circuit using op-amp is

(a) 1

(b) 2

(c) 3

(d) 4

50. Number of diodes required in full-wave rectifier using op-amp is

(a) 2

(b) 3

(c) 1

(d) 4

51. The gain of differentiator using op-amp is

(a) ωRfC1

(b) ω/RfC1

(c) −jωRfC1

(d) None

52. For a practical differentiator, the time period T of the input signal is

(a) less than time constant RfC1

(b) larger than or equal to RfC1

(c) negative of RfC1


53. The magnitude of the gain or integrator transfer function using op-amp is

(a) ωR1Cf

(b) − 1/ωR1Cf

(c) − ωR1Cf

(d) 1/ωR1Cf

54. The frequency at which the gain of integrator is 0dB is

(a) 1/2πR1Cf

(b) 1/2/πR1

(c) 2πR1Cf

(d) none

55. The gain of an op-amp decreases at high frequency due to

(a) capacitance

(b) resistors

(c) gain


56. A square wave of peak to peak amplitude 500 mV has to be amplified to a peak to peak amplitude of 3 volts, with rise time 4 µs. Find slew rate.

(a) 0.5 V/µS

(b) 0.6 V/µS

(c) 0.7 V/µS

(d) 0.8 V/µS

57. Military grade op-amp be operated in the temperature range of

(a) − 55 to 121°C

(b) − 50 to 150°C

(c) 0 to 100°C

(c) at 30°C

58. The reason for op-amp to drive any number of input devices corrected to its output is

(a) zero output resistance

(b) infinite output resistance

(c) high output resistance


59. The application of open-loop operation of op-amp is

(a) zero crossing detector

(b) square wave generator

(c) comparator


Unit 2

The frequency response of a filter circuit is best described as: 1

A graphical representation of output levels for a specific set of frequencies B the speed at which a filter responds C how well a filter suppresses one frequency

D how well a filtering circuit amplifies a given set of frequencies

The term often used to refer to the rate at which a filter attenuates is called the:

2

A transition curve B response curve C roll-off rate D band-stop response

What is the roll-off rate for a two-pole filter?

3 A —20 dB/decade

B —40 dB/decadeC —3 dB D —6 dB

The point at which a signal is considered to be blocked by a filter is:

4 A —3 dB of the input

B 70.7% of the input C called the critical frequency D all of the above

The frequency response curve of a band-stop filter can be easily identified by the:

5 A dip in output within a given band of frequencies

B peak in output within a given band of frequenciesC bandwidth D roll-off rate

6. A ________ filter rejects all frequencies within a specified band and passes all those

outside this band. A.low-pass B. high-pass C. band-pass D.band-stop

7. Identify the frequency response curve for a band-pass filter.

A.a B. b C. c D.d

8. Filters with the ________ characteristic are useful when a rapid roll-off is required because

it provides a roll-off rate greater than –20/dB/decade/pole. A.Butterworth B. Chebyshev C. Bessel D.[NIL]

9. A ________ filter significantly attenuates all frequencies below fc and passes all

frequencies above fc. A.low-pass B. high-pass C. band-pass D.band-stop

10.The gain of the multiple-feedback band-pass filter above is equal to which of the following? Assume C = C1 = C2. A.A0 = R2 / R1 B. A0 = R1 / R2 C. A0 = R2 / 2 R1

D.A0 = R1 / 2 R2

11 What are the bandwidth characteristics of a high-Q tuned amplifier? A. It will have a wide bandwidth. B. It will have a narrow bandwidth. C. Q does not affect bandwidth.

12 .

At what point does f0 approach fave? A. when Q ≥ 2 B. when Q ≤ 2 C. The values of f0 and fave are always approximately equal.

13 .

Which of the three basic active filters has the highest initial roll-off rate? A. the Butterworth filter B. the Chebyshev filter C. the Bessel filter

14 .

How many op-amps are required to build a multistage notch filter? A. one B. two C. three

15.Total phase shift required by a oscillator A.0 B.180 C.360

16. Which of the following plays a role in oscillator operation A. unity gain B. positive feedback C. negative feedback

17 .

What is the necessary phase relationship between the input and output of an oscillator?

A. There must be a 360° (or 0°) voltage phase shift. B. There must be a 180° voltage phase shift. C. The input/output phase relationship doesn't matter so long as the VAV

product is correct.

18 .

What is the term for using a circuit's output to provide the input for the circuit causing it to oscillate?

A. regenerative feedback B. unity attenuation factor C. positive damping factor

19 .

What does the Barkhausen criterion state? A. The amplifier must have unity gain to oscillate. B. The product of V AV must equal 1. C. There must be a 360° (or 0°) phase shift between input and output.

20. How many RC circuits are there in a phase-shift oscillator A. one B. two C. three

21. What types of RC circuits are in the positive feedback path of a Wien-bridge oscillator?

A. a low-pass and a high-pass filter B. two low-pass filters C. two high-pass filters

22 .

What limits the upper operating frequency of a Wien-bridge oscillator A. the clipping diodes B. the reactance of the positive feedback path C. the propagation delay of the op-amp

23 .

What is the main circuit recognition feature of the Colpitts oscillator? A. It has two tapped inductors. B. It has a tapped transformer. C. It has two tapped capacitors.

24 .

An amplifier with a center frequency of 1000 kHz has a bandwidth of 4 kHz. Determine the Q of the amplifier]

A. 250 B. 4000 C. .004 D. 5

25 .

If you wanted to get rid of the 60 Hz power line noise in a circuit, what type of filter would you use?

A. high-pass filter B. low-pass filter C. band-stop filter D. crossover network

26 .

What is one advantage of a multiple-feedback bandpass filter over a two-stage bandpass filter?

A. fewer components B. runs cooler C. higher filtration D. greater phase shift

27 .

Determine the bandwidth of a signal-pole low-pass filter that has a 20 k resistor connected between the signal input and the noninverting connection of an op-amp used as an active filter, and a 2 F capacitor between the noninverting connection and the ground for the circuit.

A. 4 Hz B. 40 Hz C. 48 Hz D. 25 Hz

28 .

Which filter type has the best frequency response? A. Chebyshev filter B. Butterworth filter C. Bessel filter D. Schmitt trigger


A graphical representation of output levels for a specific set of frequencies B the speed at which a filter responds C how well a filter suppresses one frequency D how well a filtering circuit amplifies a given set of frequencies


30

A transition curve B response curve C roll-off rate D band-stop response


31 A —20 dB/decade



32

A —3 dB of the input B 70.7% of the input C called the critical frequency D all of the above




34 Refer to the given figure. This circuit is known as a ________ filter, and the fc is ________.

A.high-pass, 1.59 kHz B. band-pass, 15.9 kHz C. low-pass, 15.9 kHz D.high-pass, 15.9 kHz

35 The bandwidth in a ________ filter equals the critical frequency.

A.low-pass B. high-pass C. band-pass D.band-stop

36. Filters with the ________ characteristic are used for filtering pulse waveforms.

A.Butterworth B. Chebyshev C. Bessel D.[NIL]

38. Refer to the given figure. The roll-off of this filter is about

A.20 dB/decade. B. 40 dB/decade. C. 60 dB/decade. D.80 dB/decade.

39. Refer to the given figure. The roll-off of the circuit shown is about

A.20 dB/decade. B. 40 dB/decade. C. 60 dB/decade. D.80 dB/decade.

40. Refer to this figure. This is a ________ filter.

A.low-pass B. high-pass C. band-pass D.band-stop

41. Which filter exhibits a linear phase characteristic?

A.Bessel B. Butterworth C. Chebyshev D.all of the above

42. Refer to the given figure. The cutoff frequency of this filter is ________, and the circuit is

known as a ________.

A.721 Hz, low-pass filter

B. 721 Hz, high-pass filter C. 72 Hz, low-pass filter D.721 Hz, band-pass filter

43. The critical frequency is defined as the point at which the response drops ________ from

the passband. A.–20 dB B. –3 dB C. –6 dB D.–40 dB

44. Filters with the ________ characteristic provide a very flat amplitude in the passband and

a roll-off rate of –20 dB/decade/pole. A.Butterworth B. Chebyshev C. Bessel D.[NIL]

45. Calculate the value of C1 = C2 for the Wien bridge oscillator to operate at a frequency of 20 kHz.

Assume R1 = R2 = 50 k and R3 = 3R4 = 600 ?

A.1.59 pF

B. 15.9 pF

C. 159 pF

D.1.59 nF

46. Only the condition A = ________ must be satisfied for self-sustained oscillations to result. A.0

B. –1

C. 1

D.None of the above

47. At what phase shift is the magnitude of A at its maximum in the Nyquist plot? A.90º B. 180º

C. 270º D.0º

48. Which of the following improvements is (are) a result of the negative feedback in a circuit? A.Lower output impedance

B. Reduced noise

C. More linear operation

D.All of the above

49.

This circuit is a ________ oscillator.

A.phase-shift

B. Wien bridge

C. Colpitts

D.Hartley

50. Refer to the given figure. The resonant frequency is controlled by

A.C3 and L1.

B. C2, C4, C5, and L1.

C. C3, C4, C5, and L1.

D.C3, C4, C5, and L2.

51. Refer to this figure. Determine the resonant frequency.

A.123.4 kHz

B. 61.7 kHz

C. 45.94 kHz

D.23.1 kHz

352 The feedback signal in a(n) ________ oscillator is derived from an inductive voltage divider in the LC circuit. A.Hartley B. Armstrong

C. Colpitts D.[NIL]

53. Given gm = 5000 S, rd = 40 k , R = 10 k , and A = 35. Determine the value of RD

for oscillator operation at 1 kHz.


A graphical representation of output levels for a specific set of frequencies B the speed at which a filter responds C how well a filter suppresses one frequency D how well a filtering circuit amplifies a given set of frequencies


55

A transition curve B response curve

C roll-off rate D band-stop response


56 A —20 dB/decade



57 A —3 dB of the input

B 70.7% of the input C called the critical frequency D all of the above




59. The lead-lag circuit in the Wien-bridge oscillator has a resonant frequency at which the attenuation is A.1/2. B. 1/4. C. 1/3. D.1/5.

60. The start-up gain of an oscillator must be ________ one.

A.equal to B. less than C. greater than

61. Refer to this figure. What is the duty cycle, if any?

A.16.3% B. 54.5% C. 86.9% D.none

62In the IC phase-shift oscillator, what should the ratio of feedback resistor Rf to R1 be? A.Zero B. Greater than –29 C. Less than 29 D.Any value

.

Unit 3 1. The circuit shown represents

(a) I to V convertor

(b) differentiator

(c) log amplifier

(d) analog inverter

Fig.1

2. A logarithmic amplifier can be used as

(a) divider

(b) multiplier

(c) subtractor


3. A multivibrator produces

(a) pure sine waves

(b) square waves

(c) distortion sine waves

(d) saw tooth voltages

4. The comparator using op-amp with input sine waveform gives

(a) cos waveform

(b) square waveform

(c) sine waveform

(d) triangular waveform

5. The output of Schmitt trigger is

(a) square waveform

(b) triangular waveform

(c) sine waveform

(d) cos waveform

6. The other name of Schmitt triggerm is

(a) regenerative comparator

(b) square wave generator

(c) backlash circuit


7. In Schmitt trigger, R2 = 100 Ω, R1 = 10 kΩ, Vref. = 0 V, Vi = 1 VPP, Vref = ± 14 V. Find VUT and VLT.

(a) 28 mV, − 28 mV

(b) 14 mV, − 14 mV

(c) 28 mV, − 14 mV

(d) − 28 mV, 14 mV

8. The time period T of square wave of astablemultivibrator using op-amp is

(a) RCln (1 + β)

(b)

(c)

(d) RC

9. If R1 = R2, then β = 0.5, the total time T of square wave in astablemultivibrator using op-amp is

(a) T = RC

(b) T = 2 RC ln 3

(c) T = 2 RCln 2

(d) T = 2RC ln(1 + 0.5)

10. The single output pulse of adjustable time direction in response to triggering signal is from _______ circuit.

(a) astablemultivibrator

(b) monostablemultivibrator

(c) bistablemultivibrator


11. The total time period of the pulse from monostablemultivibrator is

(a) T = 2 RC

(b) T = 0.3 RC

(c) T = 0.69 RC

(d) T = RC ln (1 + VD/Vsat)/1−β

12. If R1 = R2, β = 0.5, Vsat >> VD, then time period of pulse width of monostablemultivibrator is

(a) T = 2RC

(b) T = 0.69 RC

(c) T = 0.3 RC

(d) T = RC

13. The other name of astablemultivibrator is

(a) Schmitt trigger

(b) free running oscillator

(c) regenerative comparator


14. The frequency of oscillation of triangular waveform from generator using op-amp is

(a) R3/4R1C1R2

(b)

(c)

(d) C1/R1R2R4

15. A comparator is _______ and gives _______ output.

(a) Open loop op-amp, Analog output

(b) Open loop op-amp, No output

(c) Open loop op-amp, Digital output

(d) Closed loop op-amp, Digital output

16. Schmitt trigger is comparator ________ feedback.

(a) no feedback

(b) positive feedback

(c) negative feedback


17. A triangular wave can be generated by integrating

(a) cosine waveform

(b) sine waveform

(c) ramp waveform

(d) square waveform

18. The total time period of square wave of astable circuit using IC555 is

(a) T = RC × 0.69

(b) T = 0.69 (RA + RBC

(c) T = 0.69 (RA + 2RB)C

(d) None of the above

19. The duty cycle of astable circuit is defined as

(a) tON/tON + tOFF

(b)

(c)

(d)

20. Monolithic op-amp voltage comparators are advantageous than other comparators due to

(a) high response time

(b) compatible with logic families

(c) lesser in size


21. The response time of comparator increased by ___________ op-amp.

(a) compensated

(b) uncompensated

(c) monolithic


Unit 4 D/A and A/D converters

1. Which of the following is a type of error associated with digital-to-analog converters (DACs)?

a) nonmonotonic error b) incorrect output codes c) offset error d) nonmonotonic and offset error

2. A 4-bit R/2R digital-to-analog (DAC) converter has a reference of 5 volts. What is the analog output for the input code 0101.

a) 0.3125 V b) 3.125 V c) 0.78125 V d) –3.125 V

3. A binary-weighted digital-to-analog converter has an input resistor of 100 k . If the resistor is connected to a 5 V source, the current through the resistor is:

a) 50 µA b) 5 mA c) 500 µA d) 50 mA

4. What is the resolution of a digital-to-analog converter (DAC)?

a) It is the comparison between the actual output of the converter and its expected output. b) It is the deviation between the ideal straight-line output and the actual output of the

converter. c) It is the smallest analog output change that can occur as a result of an increment in the

digital input. d) It is its ability to resolve between forward and reverse steps when sequenced over its

entire range.

5. The practical use of binary-weighted digital-to-analog converters is limited to:

a) R/2R ladder D/A converters b) 4-bit D/A converters c) 8-bit D/A converters d) op-amp comparators

6. The difference between analog voltage represented by two adjacent digital codes, or the analog step size, is the:

a) quantization b) accuracy

c) resolution d) monotonicity

7. The primary disadvantage of the flash analog-to digital converter (ADC) is that:

a) it requires the input voltage to be applied to the inputs simultaneously b) a long conversion time is required c) a large number of output lines is required to simultaneously decode the input

voltage d) a large number of comparators is required to represent a reasonable sized

binary number

8. What is the major advantage of the R/2R ladder digital-to-analog (DAC), as compared to a binary-weighted digital-to-analog DAC converter?

a) It only uses two different resistor values. b) It has fewer parts for the same number of inputs. c) Its operation is much easier to analyze. d) The virtual ground is eliminated and the circuit is therefore easier to

understand and troubleshoot.

9. The resolution of a 0–5 V 6-bit digital-to-analog converter (DAC) is:

a) 63% b) 64% c) 1.56% d) 15.6%

10. Which is not an analog-to-digital (ADC) conversion error?

a) differential nonlinearity b) missing code c) incorrect code d) offset

PLL

A phase locked loop is a frequency selective circuit designed to synchronise incoming signal and maintain synchronization in spite of noise or variations in the incoming signal frequency.

1. PLL consists of

(a) Phase detector

(b) VCO

(c) Phase defector


2. VCO is designed so that at zero voltage it is oscillating at some initial frequency W0 called

(a) Cut-off frequency

(b) free-cycle frequency

(c) free-running frequency


3. The time takes for a PLL to capture the incoming signal is called

(a) pull out time

(b) capture time

(c) lock out time


4. The filter bandwidth of PLL is reduced one of the following effects.

(a) slow down the capture process

(b) increases the pull time

(c) increases the capture range

(d) decreases the interjection-injection capabilities

5. The output frequency of the VCO in PLL is given by

(a) fo = 1/4RTCT

(b) fo = RTCT/4

(c) fo =4RTCT

(d) fo = 4RTCT

6. The basic components of 565 IC is

(a) phase vector

(b) amplifier

(c) VCO


7. The maximum operated range of PLL 565 is

(a) 0 to 500 kHz

(b) 0.001 Hz to 500 kHz

(c) 100 to 400 kHz

(d) 10 Hz to 400 kHz

8. Lock in range of PLL 565 is

(a) ΔfL = 7.8f0/V

(b) ΔfL = ± 7.8f0/V

(c) ΔfL = − 7.8 f0/V

(d) ΔfL = ± 7.8V/f0

9. The capture range of IC 565 is

(a) ΔfC≈√(f1ΔfL)

(b) ΔfC≈2√(f1ΔfL)

(c) ΔfC≈√2(f1ΔfL)

(d) ΔfC≈√(f1ΔfL/2)

10. A frequency multiplier using PLL has VCO output frequency f0 is given by

(a) Nfs

(b) fs/N

(c) fs

(d) 1/Nfs

11. The frequency shift in frequency translator at the output of the VCO in PLL

(a) f0 = fs − fL

(b) f0 + fs = fL

(c) f0 = fs + f1

(d) f0 = fs − f1

12. The main advantage of PLL as a detector with other Am detector is

(a) high degree of selectivity and noise immunity

(b) low noise immunity with high degree of selectivity

(c) high degree of selectivity only

(d) noise immunity only

13. The important characteristics of PLL are

(a) lock in range

(b) capture range

(c) pull in time


14. _______ filter controls the capture range and lock range of PLL.

(a) LPF

(b) HPF

(c) BPF


15. The other name for phase detector is

(a) comparator

(b) multiplier

(c) adder


16. The application of PLL are

(a) frequency multiplier

(b) AM, FM demodulator

(c) frequency demodulator


17. The operating voltage of range of IC 565 is

(a) ±6 V to ±12 V

(b) ± 10 to ± 12 V

(c) ± 8 to ± 12 V

(d) ±12 V

18. An external capacitor connected across 565 will act as

(a) passive device

(b) low pass filter

(c) charging device

(d) discharging device

19. Let to free running frequency, VC voltage shift from VCO, the new frequency shift from VCO in a PLL is

(a) f0 + KVVC

(b) f0 − KVVC

(c) KVC

(d) f0

20. The transfer function of LPF in PLL is

(a) =1/[1+j(f1/f)]

(b) =1/[1+j(f1f)]

(c) =1/[1+j(f/f1)]

(d) 1/1 + jf1

21. The voltage VC required to derive VCO is

(a) Ve · T(f) · A

(b) Ve/T(f) · A

(c) AVe/T(f)

(d) T(f)/Ve·A

22. The maximum frequency shift of VCO in PLL is

(a) KVKφ(π/2) A(f1/Δf)

(b) KVkφ/A(f1/Δf)

(c) A(f1/Δf) (π/2)/KVkφ

(d) A(f1/Δf) KV /Kφ

23. The capture range is _______ located with respect to vco free runing frequency f0 in pll

(a) asymmetrical

(b) symmetrical

(c) opposite


24. The output waveform of pll 566 is

(a) square and triangular

(b) square and sine wave

(c) triangular and sine wave


25. The number of pins in IC-566

(a) 10

(b) 16

(c) 12

(d) 8

26. The output frequency of VCO can be changed by

(a) RT

(b) CT

(c) VC


555 Timer

1. The function of Pin 3 is:

a) Control Voltage b) Discharge c) Output d) Reset e) Threshold f) Trigger




a) Control Voltage b) Discharge c) Output d) Reset e) Threshold

f) Trigger



5. What is the function of the Threshold pin?

a) To charge the capacitor "C" b) To discharge the capacitor "C" c) To detect when the capacitor is "HIGH" d) To detect when the capacitor is "LOW"

6. What is the function of the Discharge pin?

a) To charge the capacitor "C" b) To discharge capacitor "C" c) To detect when the capacitor is "HIGH" d) To detect when the capacitor is "LOW"

7. What is the function of the Trigger pin?

a) To charge the capacitor "C" b) To discharge the capacitor "C" c) To detect when the capacitor is "HIGH" d) To detect when the capacitor is "LOW"

8. What is the function of the Reset pin?

a) To discharge the capacitor "C" b) To reset the chip c) To make the output of the chip "HIGH"

9. The Discharge and Output are:

a) In phase with each other b) Out of phase with each other

10. What does pin 6 do? a) Charges the capacitor "C" b) Discharges the capacitor "C" c) Detects the HIGH on capacitor "C" d) Detects the LOW on capacitor "C"

11. When pin 2 detects the voltage-level on the capacitor, does the capacitor begin to charge or discharge?

a) Charge b) Discharge

12. What does pin 2 do?

a) Charges the capacitor "C" b) Discharges the capacitor "C" c) Detects the HIGH on capacitor "C" d) Detects the LOW on capacitor "C"

13. In the following diagram, is the output predominantly HIGH or LOW? Remember: Pin 7 and 3 act "in harmony"

a) HIGH b) LOW

14. To increase the output frequency of a 555:

a) Increase the value of capacitor "C" b) Decrease the value of capacitor "C"

15. If the resistors in Q13 are swapped, does the output frequency change?

a) It increases (b) It decreases (c) Little or no effect 16. What does pin 7 do?

a) Charges the capacitor "C" b) Discharges the capacitor "C" c) Detects the HIGH on capacitor "C" d) Detects the LOW on capacitor "C"

17. If the value of R1 is increased:

a) The output frequency increases b) The output frequency decreases c) The overall frequency does not alter

18. Name the resistor(s) that effect the timing of the "LOW OUTPUT":

a) R1 and R2 (b) R1 only (c) R2 only 19. For a 5v circuit, if pin 4 is taken to 1v, does the chip reset?

a) Yes (b) No (c) Cannot be determined 20. When pin 2 detects the voltage-level on the capacitor, what happens to the output?

a) It goes HIGH b) It goes LOW

21. For the following diagram, which resistor(s) controls the "SPACE:"

a) R1 (b) R2 (c) R1 + R2 22. The maximum frequency of operation for a 555 is:

a) 100kHz b) 500kHz c) 5MHz d) 500Hz

Linear Integrated Circuits

Documents

filtering circuit amplifies

positive feedback path

open loop op

circuit shown represents

total time period

frequency response curve

square wave generator

frequencies bandwidth roll