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Unit 5: Fundamentals of Filters and Operational Amplifiers - Practice Quiz

ECE131 — Basic Electrical And Electronics Engineering 50 Questions
0 Correct 0 Wrong 50 Left
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1 Which component is primarily used to select or reject a specific range of frequencies in an electronic circuit?

A. Transformer
B. Rectifier
C. Oscillator
D. Filter

2 An ideal low-pass filter allows signals to pass through it if their frequency is:

A. Lower than the cut-off frequency
B. Within a specific high-frequency band
C. Exactly equal to the resonance frequency
D. Higher than the cut-off frequency

3 What is the formula for the cut-off frequency () of a simple RC filter?

A.
B.
C.
D.

4 A high-pass filter can be constructed by swapping the position of the resistor and capacitor in which circuit?

A. Low-pass filter
B. Band-pass filter
C. Voltage follower
D. Bridge rectifier

5 Which filter type passes frequencies within a certain range and rejects frequencies outside that range?

A. All-pass filter
B. Low-pass filter
C. High-pass filter
D. Band-pass filter

6 In the context of filters, what does the term 'Stopband' refer to?

A. The phase shift of the signal
B. The range of frequencies that are allowed to pass
C. The frequency where gain is 0 dB
D. The range of frequencies that are attenuated

7 What is the ideal input impedance of an operational amplifier?

A. Zero ()
B.
C.
D. Infinite ()

8 What is the ideal output impedance of an operational amplifier?

A.
B. Infinite ()
C. Zero ()
D.

9 The open-loop voltage gain () of an ideal op-amp is:

A. 100
B. Infinite ()
C. 1
D. 0

10 Common Mode Rejection Ratio (CMRR) is the ratio of:

A. Output voltage to Input voltage
B. Common mode gain to Differential gain
C. Input impedance to Output impedance
D. Differential gain to Common mode gain

11 Which parameter defines the maximum rate of change of the output voltage per unit of time?

A. CMRR
B. Slew Rate
C. Offset Voltage
D. Bandwidth

12 The concept of 'Virtual Ground' is primarily applicable to which op-amp configuration?

A. Inverting amplifier with negative feedback
B. Voltage follower without feedback
C. Open-loop comparator
D. Positive feedback oscillator

13 Why does the concept of virtual ground exist in an ideal op-amp?

A. Because the output impedance is infinite
B. Because the input impedance is zero
C. Because the slew rate is zero
D. Because the open-loop gain is infinite

14 In an ideal op-amp circuit, the current entering the input terminals ( and ) is considered to be:

A. Zero
B. Infinite
C. 1 Ampere
D. Depends on the input voltage

15 What is the voltage gain () of an inverting amplifier with feedback resistor and input resistor ?

A.
B.
C.
D.

16 The phase shift introduced by an inverting op-amp configuration is:

A.
B.
C.
D.

17 What is the voltage gain () of a non-inverting amplifier?

A.
B.
C.
D.

18 If and in an inverting amplifier, what is the gain?

A. 5
B. -5
C. 6
D. -0.2

19 If and in a non-inverting amplifier, what is the gain?

A. 1
B. 0
C. -1
D. 2

20 Which op-amp configuration acts as a 'Voltage Follower' or 'Unity Gain Buffer'?

A. Summing amplifier
B. Differentiator
C. Non-inverting amplifier with and
D. Inverting amplifier with

21 What is the primary advantage of a Voltage Follower circuit?

A. It amplifies voltage significantly
B. It acts as an impedance matching buffer (high , low )
C. It filters out low frequencies
D. It inverts the signal phase

22 An op-amp summing amplifier (adder) is typically based on which configuration?

A. Inverting configuration
B. Open-loop configuration
C. Comparator
D. Voltage follower

23 In an inverting summing amplifier with three inputs and all resistors equal (), the output voltage is:

A.
B.
C.
D.

24 To convert a summing amplifier into an averaging amplifier for 3 inputs, the ratio should be:

A. 1
B. 3
C. Infinite
D.

25 An op-amp subtractor (difference amplifier) produces an output proportional to:

A. The sum of the two input voltages
B. The product of the two input voltages
C. The integral of the input voltage
D. The difference between the two input voltages

26 In a basic differential amplifier (subtractor) circuit, if all external resistors are equal, the output voltage is:

A.
B.
C.
D.

27 Which op-amp circuit performs the mathematical operation of integration?

A. Adder
B. Comparator
C. Integrator
D. Differentiator

28 In an ideal op-amp integrator circuit, the feedback element is a:

A. Resistor
B. Diode
C. Capacitor
D. Inductor

29 If a constant DC voltage is applied to the input of an ideal op-amp integrator, the output will be:

A. Zero
B. A constant DC voltage
C. A sine wave
D. A ramp voltage (linear increase/decrease)

30 The output voltage of an ideal integrator is given by:

A.
B.
C.
D.

31 In an op-amp differentiator circuit, the input element is a __ and the feedback element is a __.

A. Resistor, Resistor
B. Capacitor, Resistor
C. Capacitor, Capacitor
D. Resistor, Capacitor

32 If the input to an ideal differentiator is a triangular wave, the output will be:

A. A triangular wave
B. A square wave
C. A sine wave
D. A cosine wave

33 A major practical disadvantage of the ideal differentiator circuit is:

A. It blocks DC signals
B. It has very low input impedance
C. It amplifies high-frequency noise
D. It cannot be built with standard components

34 When an op-amp is used as a comparator, it typically operates in which mode?

A. Closed-loop with negative feedback
B. Open-loop (no feedback)
C. Active region
D. Unity gain mode

35 In a comparator circuit, if the voltage at the non-inverting input () is greater than the voltage at the inverting input (), the output goes to:

A. Positive Saturation ()
B. Negative Saturation ()
C.
D.

36 Which application is a primary use of an op-amp comparator in Anti-lock Braking Systems (ABS)?

A. Converting wheel speed sensor signals to digital pulses
B. Amplifying the audio signal for the driver
C. Differentiation of the steering angle
D. Integrating the brake pressure

37 In an ABS system, the comparator typically compares the wheel speed sensor signal against:

A. The output of the alternator
B. The battery voltage
C. The engine temperature
D. A fixed reference voltage (e.g., Ground)

38 Why is negative feedback generally NOT used in a simple comparator circuit?

A. It is used; this statement is false
B. It creates instability
C. It reduces the gain too much
D. It slows down the switching speed

39 What happens if a differentiator input is a sine wave: ?

A.
B.
C.
D. is zero

40 In a practical integrator, a resistor is often placed in parallel with the feedback capacitor to:

A. Convert it to a differentiator
B. Reduce the gain at low frequencies (prevent saturation due to offsets)
C. Increase the bandwidth
D. Increase the slew rate

41 Bandwidth of an ideal op-amp is:

A. Finite
B. Infinite
C.
D.

42 What is the slope of the frequency response roll-off for a first-order Low-pass RC filter?

A.
B.
C.
D.

43 Which component determines the 'order' of a passive filter?

A. The voltage source
B. The number of reactive components (Capacitors/Inductors)
C. The load resistance
D. The resistor value

44 An op-amp usually requires which type of power supply?

A. Current source only
B. High voltage AC
C. Dual polarity DC supply ( and )
D. Single AC source

45 In an inverting amplifier, if the input signal is peak-to-peak sine wave and gain is -2, the output is:

A. peak-to-peak sine wave, in phase
B. peak-to-peak sine wave, phase shifted
C. peak-to-peak sine wave
D. peak-to-peak sine wave

46 Which of the following is NOT a property of an ideal Op-Amp?

A. Infinite Bandwidth
B. Infinite Output Impedance
C. Infinite Input Impedance
D. Infinite Open Loop Gain

47 In an ABS system, if a wheel locks up (stops rotating), the frequency of the pulses from the wheel speed sensor (processed by the comparator) will:

A. Invert polarity
B. Increase to infinity
C. Drop to zero
D. Remain constant

48 A Band-pass filter is effectively a cascade combination of:

A. A High-pass filter and a Low-pass filter (with overlapping passbands)
B. Two High-pass filters
C. Two Low-pass filters
D. An integrator and a differentiator

49 In a non-inverting amplifier, the input signal is applied to:

A. The output terminal
B. The feedback resistor
C. The inverting terminal (-)
D. The non-inverting terminal (-)

50 The voltage at the non-inverting input of an inverting amplifier (connected to ground) is:

A.
B.
C.
D.
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