Integrator MCQ [Free PDF] – Objective Question Answer for Integrator Quiz

11. Find R1 and RF in the lossy integrator so that the peak gain and the gain down from its peak is 40db to 6db. Assume ω=20,000 rad/s and capacitance = 0.47µF.

A. R1 = 10.6Ω, RF = 106Ω
B. R1 = 21.2Ω, RF = 212.6Ω
C. R1 = 42.4Ω, RF = 424Ω
D. R1 = 29.8Ω, RF = 298Ω

Answer: B

The gain of the lossy integration is

A=(RF/ R1)/√[1+(ωRFCF)]2

=> A(dB. = 20log{(RF/R1)/√[1+(ωRFCF)]2}

=> 40db = 20log×[(RF/R1)/√1

=> R1 = RF/20.

At ω=20000rad/s, the gain is down by 6db from its peak of 20db and thus is 14db.

The gain at 14db

=> 14db= 20log ×{[ (RF/ RF/20)] / [√(1+(200000×0.47×10-6×RF)2]}

=> 20log[1+(9.4×10-3×RF)2] = 20-14

=> RF = √3/9.4×10-3 = 212.26Ω and

R1 = 212.26Ω/10 = 21.2Ω.

 

12. Why a resistor is shunted across the feedback capacitor in the practical integrator?

A. To reduce the operating frequency
B. To enhance low-frequency gain
C. To enhance error voltage
D. To reduce error voltage

Answer: D

The input current charging the feedback capacitor produces error voltage at the output of the integrator. Therefore, to reduce error voltages a resistor (RF) is connected across the feedback capacitor. Hence, RF minimizes the variation in the output voltage.

 

13. Find the application in which integrator is used?

A. All of the mentioned
B. Analog Computers
C. FM Detectors
D. AM detectors

Answer: B

The integrator is most commonly used in analog computers mainly for signal waveshaping.

 

14. At what condition the input signal of the integrator is integrated properly

A. T = RFCF
B. T ≤ RFCF
C. T ≥ RFCF
D. T ≠ RFCF

Answer: C

The input signal will be integrated properly if the time period T of the signal is larger than or equal to RF×CF (Feedback resistor and capacitor).

 

15. What happens if the input frequency is kept lower than the frequency at which the gain is zero?

A. Circuit acts like a perfect integrator
B. Circuit acts like an inverting amplifier
C. Circuit acts like a voltage follower
D. Circuit acts like a differentiator

Answer: B

If the input frequency is lower than the lower frequency limit of the integrator (i.e. when gain = 0), there will be no integration results and the circuit act as a simple inverting amplifier.

 

16. Match the correct frequency range for integration. (Where f –> Input frequency and fa –> Lower frequency limit of integration)

1. f a i. Results in 50% accuracy in integration
2.f = fa ii. Results in 99% accuracy in integration
3.f = 10fa iii. No integration results

A. 1-iii, 2-i, 3-ii
B. 1-i, 2-ii, 3-iii
C. 1-ii, 2-iii, 1-i
D. 1-iii, 2-ii, 3-i

Answer: A

The mentioned answer gives the exact ranges where the integration starts.

 

17. Differentiation amplifier produces

A. Output waveform as the integration of input waveform
B. Input waveform as the integration of output waveform
C. Output waveform as derivative of the input waveform
D. Input waveform as derivative of the output waveform

Answer: C

A differentiation amplifier or differentiator is a circuit that performs the mathematical operation of differentiation and produces the output waveform as a derivative of the input waveform.

 

18. Determine the output voltage of the differentiator?

A. VO = RF×C1×[dVin/dt].
B. VO = -RF×C1×[dVin/dt].
C. VO = RF×CF×[dVin/dt].
D. None of the mentioned

Answer: B

The output voltage is equal to the RF×C1 times the negative instantaneous rate of change of the input voltage Vin with time.

 

19. which factor makes the differentiator circuit unstable?

A. Output impedance
B. Input voltage
C. Noise
D. Gain

Answer: D

The gain of the differentiator circuit (RF / XC1) increases with an increase in frequency at a rate of 20dB/decade. This makes the circuit unstable.

 

20. The increase in the input frequency of the differentiation amplifier to input impedance creates

A. Component noise
B. External noise
C. Low-frequency noise
D. High-frequency noise

Answer: D

The input impedance of the amplifier decreases with an increase in frequency and makes the circuit susceptible to high-frequency noise such that noise can completely override differential output.

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