Damping Coefficient and Resonant Frequency of a 2nd order circuit

In summary, the speaker is confused about how to find the damping coefficient and resonance frequency for a second order circuit. They mention that there are tables for standard circuits but they need to know how to solve for these values in general. The professor's notes and textbook do not provide enough detail on how to solve for these values. The speaker knows that they will eventually need to solve a second order differential equation, but they are unsure of how to proceed. They mention the need to create a table for the circuit, similar to one in the textbook, for their exam.
  • #1
gfd43tg
Gold Member
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Hello,

I am having major confusion for how to find the damping coefficient, α, and the resonance frequency, ωo, for a second order circuit, in general. I know that there are tables for standard circuits like a series RLC and parallel RLC giving those values, but I am certain that I need to know how to solve for them in general.

The professors notes did not even show how to do the series RLC circuit without a ton of handwaving to the point of being unfollowable. The textbook (he wrote it) does not have it in full detail either. It just essentially presents the results. He made it very clear to us that we need to know how to do it for either 2 inductors separated by resistors or 2 capacitors separated by resistors, and tables for those are not in the textbook.

I know that once I clean up the circuit through my KCL equations, I will eventually get a 2nd order DE that looks like this

v'' + av' + bv = c

From here, I am stuck with how I should proceed to find those parameters so I can determine if my circuit is over or underdamped, or critically damped.

Thank you
 
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  • #2
To be clear, I absolutely need to make a table that is the same as this (from textbook)

ImageUploadedByPhysics Forums1398397130.746444.jpg



For the first two circuits in this figure

ImageUploadedByPhysics Forums1398397168.878329.jpg


So I can put them on my cheat sheet. I always wondered why go through so much effort to make these tables, but then explicitly tell us that neither are going to be on the exam, and it will be something else, but I digress.
 

1. What is the damping coefficient in a 2nd order circuit?

The damping coefficient in a 2nd order circuit is a measure of how quickly the oscillations in the circuit die down. It is represented by the symbol "ζ" and is typically given as a decimal value between 0 and 1. A higher damping coefficient indicates a faster decay of the oscillations.

2. How is the damping coefficient related to the resonant frequency?

The damping coefficient and resonant frequency are inversely related in a 2nd order circuit. This means that a higher damping coefficient results in a lower resonant frequency, and vice versa. This relationship is represented by the equation ω0 = 1/√(LC), where ω0 is the resonant frequency, L is the inductance, and C is the capacitance in the circuit.

3. What is the significance of the resonant frequency in a 2nd order circuit?

The resonant frequency is the frequency at which the circuit will have the highest amplitude of oscillations. This means that the circuit will be most responsive to this frequency and will have the largest output. It is an important parameter to consider in designing and analyzing 2nd order circuits.

4. How does the damping coefficient affect the stability of a 2nd order circuit?

The damping coefficient plays a crucial role in determining the stability of a 2nd order circuit. A higher damping coefficient results in a more stable circuit, as it prevents the oscillations from growing too large and causing instability. On the other hand, a lower damping coefficient can lead to instability and can cause the circuit to become unresponsive.

5. What are some practical applications of understanding damping coefficient and resonant frequency in 2nd order circuits?

Understanding the damping coefficient and resonant frequency in 2nd order circuits is essential in a variety of practical applications. It is used in the design and analysis of electronic circuits, such as filters and amplifiers. It is also important in the field of mechanical engineering, where damping and resonant frequencies play a critical role in designing and controlling vibrations in structures and systems.

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