# Homework Help: More details on transient response

1. Apr 15, 2012

### Noway

Hi guys
I just stepped into the electronic fields, I have some problems confusing me a lot

I read my lecture notes but I was confused by a term transient response modes

From my lecture notes, it describe this term in linear/first order and second order system
But I'm still confused
Like what are all those response about

And I do believe that they are related to my previous learning
Like we can describe all those modes by some mathematical equations
So what are those equations?

2. Apr 15, 2012

### Staff: Mentor

Hi Noway! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]
When you switch power to a circuit, that circuit responds with a short-lived ('transient') component in its output but this dies away and leaves you with just the forced response that you can attribute to the input.

A second order system can have oscillations in its transient (short-lived) response, and these die away leaving you with the output you were expecting. A first order system is just a bit slow to respond, or a bit sluggish, but it can't oscillate.

A good example is a moving coil meter, say a voltmeter. When you connect it to a battery to measure voltage, does the needle swing beyond its final position then oscillate back and forth a bit before settling on the final reading? If so, that is typical of a second order response. (Though not all second order responses necessarily do oscillate like that, they potentially can.)

The equations are first order differential equations, and second order differential equations. A google search will find you plenty of information to remind you, if you have previously studied these.

Last edited by a moderator: May 5, 2017
3. Apr 15, 2012

### Noway

Thank you mate
I'm now clear with the definition of this term and some realistic examples

How about the mathematical equations for the transient response modes?
I do believe there are some equations to describe all those modes?

I have some info on my lecture notes but they are not clear enough for me
The lecture notes say that there are several modes to describe the transient response
Would you mind telling me what are those modes and how I can describe them mathematically?

Last edited by a moderator: May 5, 2017
4. Apr 15, 2012

### Staff: Mentor

Sorry, I can't, as I do not associate the word "mode" with anything to do with 1st or 2nd order systems. Possibly it may be to do with the degrees of damping, whether under-, critically-, or over-damped, but in neither mathematics or engineering do I recall "mode" associated with damping, either.

I'll have to leave that for someone else to address, or you could try google. Perhaps your lecture notes might offer a further clue?

5. Apr 15, 2012

### Noway

Thank you dude anyway
I tried google but cant find them
the lecture notes confused me a lot T.T

6. Apr 15, 2012

### Staff: Mentor

I meant if you were to post an excerpt from your lecture notes it might offer some reader here a clue as to what mode relates to.

7. Apr 15, 2012

### Noway

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Last edited: Apr 15, 2012