If Barkhausen criterion is not fulfilled by an oscillator circuit, it will: a. Stop oscillating b. Produce damped waves continuously c. Become an amplifier d. Produce high-frequency whistle
The correct answer and explanation is:
The correct answer is b. Produce damped waves continuously.
Explanation:
The Barkhausen criterion is a fundamental principle used to determine whether a circuit will oscillate or not. It specifically applies to oscillators, which are circuits designed to produce a continuous output signal, usually in the form of sinusoidal waves. According to the Barkhausen criterion, for sustained oscillations to occur, two conditions must be satisfied:
- The loop gain must be equal to or greater than one: The total gain around the feedback loop (including both the amplifier and the feedback network) must be sufficient to maintain oscillations.
- The phase shift around the loop must be zero or an integer multiple of 360 degrees: This condition ensures that the feedback is in phase with the input signal, providing positive feedback that sustains oscillations.
If these conditions are not met, the oscillator will not produce a stable, continuous oscillation. In such a case, the circuit will behave as follows:
- Damped Waves: If the Barkhausen criterion is not fulfilled, the feedback loop does not provide the necessary conditions for sustained oscillations. This causes the oscillations to gradually lose energy over time, leading to a damped oscillation. The amplitude of the oscillations decreases, and the waveform will eventually fade out. This is why the answer is b. Produce damped waves continuously.
- Other Outcomes:
- a. Stop oscillating: This would be true if the oscillator simply fails to start, but if it starts, it would still produce damped waves.
- c. Become an amplifier: While the circuit could act as an amplifier if it doesn’t oscillate, this is not a direct consequence of not meeting the Barkhausen criterion.
- d. Produce high-frequency whistle: This could be a symptom of an oscillating circuit but would not be the result of failing the Barkhausen criterion, where the oscillations would eventually die out.
Thus, when the Barkhausen criterion is not met, the system produces damped oscillations, which eventually stop.
Now, I’ll generate an image that visually represents this concept.
Here is the diagram of an oscillator circuit showing damped waves, illustrating the failure to meet the Barkhausen criterion. The image highlights the decreasing amplitude of oscillations over time, symbolizing the damped nature of the waves in the absence of proper conditions for sustained oscillations.
