On the stability of an LTI circuit

In summary, a stable LTI circuit composed of resistors, capacitors, and inductors will have an impulse response that decays over time. This is supported by laws of energy conservation and the transfer function of the system must have poles on the left-half side of the complex plane. This is related to Kirchhoff's Laws and is also confirmed by the Routh-Hurwitz stability criterion. Ultimately, the system cannot exhibit divergent behavior or a stable continuous oscillation due to the presence of resistance and energy conservation.
  • #1
mjtsquared
3
3
An LTI circuit such as one composed of resistors, capacitors, and inductors, in general is a stable LTI system, i.e. its impulse response is one that decays over time. I have no problem with that, as it speaks for itself through laws of energy conservation, but I want to see this from a mathematical standpoint.

Following from this assumption, the transfer function of the system must have poles on the left-half side of the complex plane i.e. the real parts of the potentially complex roots of the denominator polynomial are negative. I know about the Routh-Hurwitz stability criterion, and have used it on many examples which do pass the criterion, but I still can't find any generality. If it's something that always allows this to happen, it must be something with Kirchhoff's Laws. What do you think?

Good day!
 
  • Like
Likes berkeman
Physics news on Phys.org
  • #2
If an impulse was fed in and the energy in the system grew exponentially without bound, that would be generating energy from nothing. That rules out divergent behavior. Also, any resistance at all would bleed off energy. That rules out a stable continuous oscillation.
 

1. What is an LTI circuit?

An LTI (linear time-invariant) circuit is a type of electronic circuit that follows the principles of linearity and time-invariance. This means that the output of the circuit is directly proportional to the input and is not affected by changes in time or frequency.

2. How is the stability of an LTI circuit determined?

The stability of an LTI circuit is determined by analyzing its transfer function, which describes the relationship between the input and output signals. If the transfer function has all of its poles in the left half-plane, the circuit is stable. If any poles are in the right half-plane, the circuit is unstable.

3. Why is stability important in an LTI circuit?

Stability is important in an LTI circuit because an unstable circuit can lead to unpredictable and potentially dangerous behavior. It can also affect the accuracy and reliability of the circuit's output.

4. How can stability issues be addressed in an LTI circuit?

Stability issues in an LTI circuit can be addressed by using various design techniques such as feedback control, adding compensation components, or changing the circuit's topology. These methods can help to shift the poles of the transfer function to the left half-plane and improve the circuit's stability.

5. Are there any limitations to the stability analysis of an LTI circuit?

Yes, there are some limitations to the stability analysis of an LTI circuit. For example, the analysis assumes that the circuit is operating in a linear region and that the components are ideal. In reality, there may be nonlinearities and imperfections that can affect the stability of the circuit. Additionally, the analysis may not be accurate for circuits with time-varying parameters or for high-frequency signals.

Similar threads

  • Electrical Engineering
Replies
5
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
1K
  • Other Physics Topics
Replies
1
Views
953
  • Engineering and Comp Sci Homework Help
Replies
2
Views
3K
Replies
2
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
Back
Top