Ideal LC oscillator and barkhausen criterion

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The discussion centers on the relationship between the Barkhausen criterion and the Ideal LC oscillator, particularly in the context of oscillations with initial conditions. It highlights that an LC circuit, even with an initial voltage, does not inherently provide feedback necessary for applying the Barkhausen criterion. The conversation also addresses the scenario of introducing negative resistance to counteract losses in the inductor, questioning the applicability of the criterion in this case. The distinction between an LC circuit and a feedback system is emphasized, noting that true oscillators require amplification and feedback to sustain oscillations. Ultimately, understanding the role of feedback is crucial for applying the Barkhausen criterion effectively.
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I am unable to relate the Barkhausen criterion for oscillations to sustain to the Ideal LC oscillator with an initial condition.
Assume you have a parallel combination of LC(both with Q=infinity) with an initial condition say V volts on capacitor. Mathematically it will oscillate with the frequency 1/2/pi/sqrt(LC). Now I see no feedback here. where you apply barkhausen criterion for the oscillations in that feedback system?

Even if there is a loss in inductor and I keep a -ve resistance in parallel to cancel out that loss, how can i apply the Barkhausen criterion for this as well.
 
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asifshaik said:
Now I see no feedback here. where you apply barkhausen criterion for the oscillations in that feedback system?

LC isn't a feedback system. A feedback system is when a sampled output of a network is fed back its input:

220px-Oscillator_block_diagram.svg.png



Oscillators work on the principle that the resonant element is amplified with an external amplifier, and then the amplified output is fed back to its input in correct phase as established by Barkhausen's criterion in order to sustain oscillations indefinitely.
 
Thank you very much for the reply.
 
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