Sketch the waveform to represent the transient response

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Discussion Overview

The discussion revolves around sketching waveforms to represent the transient response of second-order circuits characterized by specific transfer function parameters. Participants explore the implications of different damping ratios (ζ) and natural frequencies (ω) on the system's response, focusing on under-damped and over-damped cases. The context is primarily homework-related, involving mathematical reasoning and conceptual clarification.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • Participants discuss the parameters for three cases of transient response, noting the calculations for damped natural frequency (wd), time to peak overshoot, and overshoot for each case.
  • Some participants inquire about the type of input signal (step, delta, ramp) to use for solving the ordinary differential equation (ODE) related to the system's response.
  • There is uncertainty about how to draw the graphs representing the transient response, with participants expressing confusion over the relationship between input and output signals.
  • One participant suggests assuming a step input and questions how to represent the output graphically, indicating a lack of clarity on the expected waveform.
  • Another participant encourages looking up second-order system responses to find appropriate graphs for the given parameters.
  • Later, a participant shares a graph they created based on their research and seeks feedback on its accuracy.
  • There is an emphasis on understanding the relationship between the ODE and the resulting waveforms, highlighting the need for initial conditions to derive specific solutions.

Areas of Agreement / Disagreement

Participants generally agree on the need to assume a step input for the analysis, but there remains uncertainty about how to accurately draw the corresponding waveforms. Multiple viewpoints exist regarding the interpretation of the input and the resulting output graphs, indicating that the discussion is not fully resolved.

Contextual Notes

Participants express limitations in their understanding of how to graphically represent the transient response without clear definitions of the input signal and the expected output. There are unresolved questions about the initial conditions required for the ODE and how they affect the waveform representation.

Connorm1
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Homework Statement


Sketch, on a set of common axes, waveforms to represent the transient
response of circuits having transfer functions with the following parameters:

a) ζ = 0.5, ω = 1×10^3 rad s^-1
b) ζ = 0.2, ω = 2×10^3 rad s^-1
c) ζ = 2, ω = 1×10^3 rad s^-1

Homework Equations


wd=wo√(1-ζ^2)
Time to peak overshoot = π/wd
overshoot = e-(ζπ)/(√(1-ζ^2))

The Attempt at a Solution


So with this in mind for
a)
wd=(1*103)√(1-0.5^2) = 866.025
Time to peak overshoot = π/wd = 0.00363seconds
overshoot = e-(ζπ)/(√(1-ζ^2)) = 0.16303

b)
wd=(2*103)√(1-0.2^2) = 866.025
Time to peak overshoot = π/wd = 0.00363seconds
overshoot = e-(ζπ)/(√(1-ζ^2)) = 0.16303

c) will have no overshoot as ζ = 2>1 (which means no oscillation).

How do i actually draw these as graphs now? is there more info i need?

do i also need to use
70a65de9499e2ee26449ef7e0ef7f22b4158ae9f
?
 
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What's the input? Step? Delta? Ramp? ...
Given this you can solve your ODE but there are many places to look up under-damped, critically damped, and over-damped 2nd order systems.
 
This is what I'm unsure of, if it mentioned one of the above i could work through it via my notes... I've only encountered step change input for second order systems. Thus i understand which ones are under-damped (a/b) and which are over-damped c if this is the case. But how do i draw this? only thing i can see from the graph is y(t)=1 but how do i find x(t) & the time period...
 
Connorm1 said:
This is what I'm unsure of, if it mentioned one of the above i could work through it via my notes... I've only encountered step change input for second order systems. Thus i understand which ones are under-damped (a/b) and which are over-damped c if this is the case.
Assume step input then.
But how do i draw this? only thing i can see from the graph is y(t)=1
Say what? The output is a constant dc voltage? And what graph? You haven't provided one for us to look at.
You have the information you need to draw the output graphs. I suggest looking up the various possible graphs depending on ζ and ω for a step input. Widely available on the web.
 
rude man said:
Assume step input then.Say what? The output is a constant dc voltage? And what graph? You haven't provided one for us to look at.
Apologies I think I've gotten myself confused... I think I am looking too deep into it. I'll be back when i have some form of graph! Thanks for your help @rude man
 
Connorm1 said:
Apologies I think I've gotten myself confused... I think I am looking too deep into it. I'll be back when i have some form of graph! Thanks for your help @rude man
Good idea. Google "second order systems responses". The curves will all be there.
 
@rude man so after searching through second order system responses I have a graph that looks like this. How does it look?
 

Attachments

That's the idea.
Make sure yu understand which waveform corresponds to your values of ωn and ζ.

You should also understand how your ODE in your post 1 solves to those waveforms. That equation requires one or two initial conditions otherwise you get nothing from it.
 

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