Question

What is the minimum voltage gain required for the Colpitts Oscillator shown in the below figure for sustained oscillations?

• A. 1
• B. 2
• C. 4
• D. 3

Hint:

For sustained oscillations in an oscillator circuit, ensure that the gain meets the required condition based on the Barkhausen criterion.

Answer 1

The Correct Option is B

For sustained oscillations in a Colpitts oscillator, the Barkhausen criterion must be satisfied, which requires that the total phase shift around the loop is 360° and the loop gain is 1 or greater. To achieve this, the voltage gain must be at least 2. This is because the feedback network and the active device must provide the necessary gain to compensate for any losses in the circuit and sustain oscillations.
Conclusion: The minimum voltage gain required for sustained oscillations in the Colpitts oscillator is 2.