# Transient RLC circuit

Discussion in 'Homework Help' started by ham3388, Oct 8, 2012.

1. ### ham3388 Thread Starter Member

Jul 3, 2012
97
3
Hi friend

I'm just wondering if i'm on the right track for the problem. I have started analysing the circuit, but I'm really unsure of my method of analysis.

Im really lost, could some one help me here

My regards

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2. ### WBahn Moderator

Mar 31, 2012
23,847
7,378
I can't make out much on the scanned images of your work, there just isn't enouch contrast for me to read it. Please try to get higher contrast, perhaps by going over the work with a black pen or perhaps even a fine point felt-tip marker.

ham3388 likes this.
3. ### ham3388 Thread Starter Member

Jul 3, 2012
97
3
Hi Wbahn....

Its visible if you open it by PAINT.

My regards

4. ### ham3388 Thread Starter Member

Jul 3, 2012
97
3
Realy noody can help in this problem,,,,?

5. ### mlog Member

Feb 11, 2012
276
36
At the risk of appearing dense, what is 100 vi? Is it a voltage source or a current source that is dependent on vi, i.e. current=100 times vi?

6. ### ham3388 Thread Starter Member

Jul 3, 2012
97
3
Based on the modules worked examples, it suppose to be voltage source...

7. ### mlog Member

Feb 11, 2012
276
36
The reason I asked is usually an arrow denotes a current source. Since the source says "100vi," I thought it could be a dependent current source based on a voltage "vi." In other words, if vi=1 millivolt, then the current source 100vi=100 milliamp. You would think the notation would be standard, but it doesn't seem to be.

8. ### mlog Member

Feb 11, 2012
276
36
Why don't you post Figure 4?

9. ### ham3388 Thread Starter Member

Jul 3, 2012
97
3
Ok here is the FIG 4

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10. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
510
My question as well. The problem is gibberish in it's specs. It is shown as a voltage dependent current source.

11. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
510
This problem really is absurd. It asks to find the step response and at the same time correctly states that a step response from a thermocouple is IMPOSSIBLE since it measures temperature and any thing with mass can not change it's temp instantly. Idiocy.

But one point: assuming it is a voltage source that "steps", it is connected to an inductor. The current through an inductor can NOT change instantly (step) so it ramps up or down in response to the voltage steps. That is how the L-C filter works, so the steps can never appear at the resistor side.

It should also be noted that the voltage across a cap can never change in zero time so that at t+ (the instant after after the step), all the step voltage appears across the inductor and the cap voltage is unchaged from previous instant. In the following time the current ramps up through the inductor and the cap voltage gradually changes to the new steady state value.

Last edited: Oct 13, 2012