# online course - (Laplace Transform problem)

Discussion in 'Homework Help' started by notoriusjt2, Mar 2, 2010.

1. ### notoriusjt2 Thread Starter Member

Feb 4, 2010
209
1
I am in an online course and the questions/examples from the book are quite terrible. I have read the entire chapter and this is the first question from my chapter quiz. Could someone please post the basic steps(not the answer) needed to solve this problem as I am honstley clueless. I will then use those steps to try to solve the problem. Thank You

2. ### loosewire AAC Fanatic!

Apr 25, 2008
1,584
443
Look up and study in wikipedia,a lot of information on your
study.

3. ### dachikid Member

Oct 19, 2007
16
0
You might want to start by determining the impedance of the circuit withn the time domain. From there it's just a hop-skip and a jump away to the Laplace transform.

4. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
790
While it might be informative there's no need to do that.

This is the process I would adopt.

1. Convert all components to the 's' domain.
An Inductor L becomes Ls
A Capacitor C becomes 1/(Cs)
A Resistor R stays as R
2. Treat the circuit as if it is a series-parallel network and solve it using techniques you have applied to series-parallel resistive networks in the past.

So then, that part of the circuit comprising the (1/2)F (or 2/s) capacitor in parallel with the 1Ω resistor would become

(2/s)/(1+2/s) [Remember two resistors in parallel - R1*R2/(R1+R2)]

To this you would add the (4/3)H or (4s/3) inductor term.

So that entire branch is equal to [4s/3 + (2/s)/(1+2/s)]. That branch is in parallel with the lone (3/2)F or (2/3s) capacitor.

It's just more fiddly than manipulating purely resistive terms because the algebra is complicated by the terms in 's' - but it's still just a process of careful algebraic manipulation.

Have a go at doing the problem - even if you go wrong, someone can then help you.

Last edited: Mar 2, 2010