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Unit 5 - Practice Quiz

ECE131

1 Which component is primarily used to select or reject a specific range of frequencies in an electronic circuit?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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. 2
C. -1
D.

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

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

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

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

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

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

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. 3
B. 1
C.
D. Infinite

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

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

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. Differentiator
B. Integrator
C. Comparator
D. Adder

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

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

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

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

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

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

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

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

A. It blocks DC signals
B. It amplifies high-frequency noise
C. It has very low input impedance
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. Unity gain mode
D. Active region

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

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

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

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

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

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

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

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

41 Bandwidth of an ideal op-amp is:

A.
B.
C. Finite
D. Infinite

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

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

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

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 Input Impedance
B. Infinite Bandwidth
C. Infinite Output 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. Increase to infinity
B. Remain constant
C. Drop to zero
D. Invert polarity

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 Low-pass filters
C. Two High-pass filters
D. An integrator and a differentiator

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

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

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

A.
B.
C.
D.