# RLC circuit step response time domain

1. Dec 15, 2008

### ankh

This is more of a math question but i feel like i will get more help among Electrical Engineers.

I successfully found the step response of an RC circuit in the time domain using Laplace Transforms.

But i cant seem to figure out how to do it with an RLC transfer function.

I have the following transfer function for a series RLC with a step input:

http://img201.imageshack.us/my.php?image=38900900ag5.png

a push in the right direction would be appreciated.

cheers

2. Dec 15, 2008

### Dr.D

I suggest that you unwind your Laplace transforms and write the description again as a differential equation. You will then need to find homogeneous and particular solutions to the differential equation. In engineering terminology, these are often called the transient and steady state solutions for the differential equation. But the first step is to back away from the Laplace transforms and go back to differential equation notation and thinking.

3. Dec 15, 2008

### ankh

ye lol i just used matlab

syms s
C=....equation..
c=ilaplace(C)

if anyone wants to post how to do it by hand, go ahead. I don't need to do it by hand for this particular assignment.

Thanks for help. I do see now how to do it band nut i am to lazy to do it.

4. Dec 15, 2008

### Dr.D

Evidently lazy is the operative word here.