Electrical Engineering Challenge #5

[Cornel]

Hi,

Find the current through C1, voltage across L1 and voltage across R3. Analysis must be done using odesolve block (but of course other methods are welcome).

[ttokoro]

This challenge has no answer from SNS.

If using normal values of R,L,C, mathcad can solve this circuit by using laplace transform.

However, tau of RL is almost inpulse responce and CR is second order, so calculation soon over 10^304 and stop. 

For initial challenge condition, my answer using best effort of mine is this.

Please check or post your answers.

[ttokoro]

Check the direction of current and voltages of turn on and off times, this is more good answer.

[Cornel]

What is SNS? 

And post Mathcad file or the complete solution through images on how did you got these latest results. As far as I remember these should be the correct plots. 

I have also some results, but I see that using initial challenge conditions the error with calculation reached 10^308 or whatever does not allow me to plot these results. I can show my calculations from Monday. But calculations are based only on laplace transform as you did  (I see that is very hard to obtain any solution by using solve block, as was the initial solution request)

[ttokoro]

More good answers. Pulse of iC1 needs more study to check.

[Cornel]

Using your first approach with laplace transform (as using odesolve we cannot obtain any solution so far):

My approach is this with the same results as your:

So, I do not know how you obtained this results. You need to post mathcad file or imgs with complete solution...

[Cornel]

On the other hand, we can see that such a simple circuit creates such problems :)), do not know why

[Werner_E]

Use the input values ttokoro had used and you get a result

[Cornel]

I know this that with these input values ttokoro had used initially we can have some plot results, but these values were not first values. Also, he was able to obtain somehow this plot results, which these plot results are more for these values (the first stated values of this problem):

[Werner_E]

He didn't show that he really used these exact input values.
So the pictures he posted are rather worthless, I guess.

It's a bit tedious because ttokoro usually wants to be asked to send his worksheet first. But I think he will eventually do that here too. You'll have to wait for him to answer.

[Cornel]

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@Werner_E wrote:

He didn't show that he really used these exact input values.
So the pictures he posted are rather worthless, I guess.

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Yes, this is why I said in one of my earlier post:

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@Cornel wrote to ttokoro:

And post Mathcad file or the complete solution through images on how did you got these latest results.

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[ttokoro]

These two pictures are DC and pulse responces of original circuit made by maple 2022. Blue plot shows vR3 and red line shows vL1.

So only the initial and after pulse responces are able to solve. ( I am a biginer of maple. But error message shows same for mathcad, such as over 10^304 like.)

Using mathcad, every DC responce is solved and augment all data set. The tips is not using C value at first but after inverslaplace symbolic results, the value of C is substituted.  

[Cornel]

I will make now another variant of this topic with this circuit removing R1 resistor, because this circuit is very simple and I want to know why odesolve block cannot solve this circuit...

[Cornel]

For me its also strange that this exercise seems to not be possible to solve with odesolve block...