# Frequency Filters – 2 MCQ’s

This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Frequency Filters – 2″.

1. Find which one is a sallen-key topology.

a)

2. Considering a second-order Butterworth LPF using an op-amp, where damping factor = 1.414 find the value of R3, given the following circuit. (R2=5kΩ)

a) 6.71 kΩ

b) 4.22 kΩ

c) 2.93 kΩ

d) 5 kΩ

3. For the following circuit, R2=220kΩ, R1=10kΩ, find the maximum gain and the phase shift at the cutoff frequency.

a) Maximum gain = 22, Phase shift = 45°

b) Maximum gain = 23, Phase shift = 135°

c) Maximum gain = 22, Phase shift = 225°

d) Maximum gain = 23, Phase shift = 45°

4. A first-order Butterworth low pass filter is an interconnection of ____________ and ___________

a) Single low pass RC circuit, Voltage follower

b) Low pass RC circuit, Band-pass RC circuit

c) Low pass RC circuit, LC feedback

d) Single low pass RC circuit, Power amplifier

5. Find the cutoff frequency for the following circuit. (R1=R2=20kΩ)

a) 25 kHz

b) 3987 rad/sec

c) 2500 Hz

d) 25000 rad/sec

6. Given a second-order Butterworth HPF, find the maximum gain magnitude.

a) 1.586 dB

b) 4 dB

c) 2.66 dB

d) 1 dB

7. Which of these is incorrect for a band-stop filter?

a) An adder is required when designing it using LPF and HPF

b) LPF and HPF are connected in parallel

c) The HPF cut-off frequency should be much higher than LPF cut-off frequency

d) The LPF and HPF are connected in series

8. Consider the following circuits.

If a band-pass filter is created by using the

above two circuits in cascade, find the correct relation from the choices below.

a) R_{4}C_{2} >> R_{1}C_{1}

b) R_{4}C_{2} << R_{1}C_{1}

c) R_{6}R_{5} = R_{2}C_{3}

d) R_{4}C_{2} = R_{1}C_{1}

9. Which of these is wrong for an all-pass filter?

a) It is used for phase equalization in a communication system

b) It is used in landline communication

c) Its phase shift is -2tan^{-1}RC, between 0 to -180°

d) It can be made using a single op-amp