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These are the correct answers

1. Answer: c
Explanation: RC phase shift oscillator contains a minimum of three phase shift network. There can be also four and it increases the stability of oscillation. They yield a pure sine wave for a variety of loads.
2. Answer: a
Explanation: One phase shift network of an RC phase shift oscillator contains one capacitor and one resistor. This single network causes a phase shift of 60° and a total of 180° through the amplifier stage and 180° through the second inverting stage, a total of 0.
3. Answer: d
Explanation: One phase shift network of an RC phase shift oscillator contains one capacitor and one resistor. There is no need of an inductor.
4. Answer: a
Explanation: One phase shift network of an RC phase shift oscillator contains one capacitor and one resistor. This single network causes a phase shift of 60° and a total of 180° through the amplifier stage and 180° through the second inverting stage, a total of 0.
5. Answer: b
Explanation: Phase shift provided by one phase shift oscillator in RC phase shift oscillator in 3 stage is 60 degrees. It is 180/number of stages.
6. Answer: a
Explanation: To satisfy Barkhausen’s criteria total phase shift should be 360 degrees. 180 degrees is produced by amplifier and rest by phase shift network even it is three stage or four stage.
7. Answer: b
Explanation: The phase shift oscillator will produce a phase shift of 180 degrees only at a particular frequency by which it is meant to oscillate.
8. Answer: a
Explanation: Phase shift network doesn’t initialize the oscillation it just phase shift a given frequency. Oscillation will start by noise inherent of transistor or by minor voltage variations in DC source.
9. Answer: d
Explanation: Amplifier gain should be minimum of 29 or else Aβ will be less than one.
10. Answer: b
Explanation: Phase shift provided by one phase shift oscillator in RC phase shift oscillator in 4 stage is 45°. It is 180/number of stages.
11. Answer: c
Explanation: For a RC phase shift oscillator the frequency formula is 1/2πRC√2N where N is the total number of RC stages. For a 3 stage circuit, the frequency is 1/2πRC√6.
12. Answer: c
Explanation: Distortion in output of phase shift oscillator is less 5%.
13. Answer: d
Explanation: Since only one frequency can fulfill barkhausen’s criteria requirement positive feedback occurs only for one frequency. Hence pure sine wave is not possible.
14. Answer: b
Explanation: The feedback factor for RC phase shift oscillator is 1/29 and to satisfy Barkhausen’s criteria amplifier gain should be greater than 29.
15. Answer: a
Explanation: Oscillator frequency can be given by the equation 1/2πRC√6 = 0.065/RC = 928.57Hz.