This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Weinbridge Oscillator”.

1. At the resonant frequency, what is the phase shift for the output in a Wien Bridge oscillator?

a) 0°

b) 45°

c) 90°

d) 180°

2. Consider the circuit shown below.

Given that R1=20kΩ, C1=2nF, R2=20kΩ, C2=2nF, find the approximate resonant frequency.

a) 4kHz

b) 3kHz

c) 25kHz

d) 15kHz

3. Which of these is incorrect for a Wien Bridge oscillator?

a) Low distortion

b) Good stability at the resonant frequency

c) Difficult to tune

d) Based on frequency selective form of a Wheatstone bridge

4. The following circuit is provided. R1=R2 and C1=C2.

What is the correct choice for sustained oscillation?

a) R1 = R2

b) R4 = 2R3

c) R4 = 3R3

d) R1 = R2 = R3 = R4

5. In the below circuit, the output frequency is 0.5 Mhz.

C1 = 5nF, R4 = 40kΩ, R3 = 20kΩ. Find the value of R.

a) 63Ω

b) 220Ω

c) 127Ω

d) 55Ω

6. Which of these is a disadvantage of the Wien Bridge oscillator?

a) It cannot fabricate a pure tune

b) Distortion observed in output is high

c) It cannot be used for high resistance values

d) There is no automatic gain control

7. For any Wien Bridge oscillator, R1 = R2 and C1 = C2 always in the bridge, provided the phase shift through the amplifier is zero.

a) True

b) False

8. In a Wien bridge oscillator, it is found that at the frequency ω_{O} there is no phase shift in R_{F}/R gain loop and the phase shift of the amplifier is also zero. Then what is the equation for the radian frequency, given R_{1}, C_{1} is the series network of bridge and R_{2}, C_{2} is the parallel network?

a) ω_{O}=1/R_{1}C_{1}

b) ω_{O}=1/R_{2}C_{2}

c) ω_{O}=1/R_{1}R_{2}C_{1}C_{2}

d) ω_{O}=1/RFC_{1}RC_{2}