Ideal LC oscillator and barkhausen criterion

  • Thread starter Thread starter asifshaik
  • Start date Start date
  • Tags Tags
    Lc Oscillator
Click For Summary
SUMMARY

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 is established that an Ideal LC oscillator, defined by a parallel combination of inductance (L) and capacitance (C) with infinite quality factor (Q), oscillates at a frequency of 1/2π√(LC) without inherent feedback. The Barkhausen criterion, which requires feedback for sustained oscillations, cannot be applied directly to an LC circuit without an external amplifier to provide the necessary feedback loop.

PREREQUISITES
  • Understanding of the Barkhausen criterion for oscillations
  • Knowledge of Ideal LC oscillators and their characteristics
  • Familiarity with feedback systems in electronic circuits
  • Basic principles of resonant circuits and amplification
NEXT STEPS
  • Study the principles of feedback systems in electronic oscillators
  • Learn about the role of amplifiers in sustaining oscillations
  • Explore the mathematical derivation of the Barkhausen criterion
  • Investigate the effects of resistance and quality factor (Q) on oscillator performance
USEFUL FOR

Electrical engineers, students of electronics, and anyone interested in the design and analysis of oscillators and feedback systems.

asifshaik
Messages
7
Reaction score
0
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.
 
Engineering news on Phys.org
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.
 

Similar threads

Replies
5
Views
10K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
Replies
152
Views
7K
Replies
4
Views
5K
  • · Replies 11 ·
Replies
11
Views
7K
  • · Replies 30 ·
2
Replies
30
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K