Getting started with Laplace in MathCAD

Forum|Forum|7 years ago
October 2, 2018
4 replies
11006 views

I am trying to get started with Laplace transform in MathCAD 15 and I would like help to find what I did wrong in the document I uploaded.

It’s a simple second order RC circuit. V1 is a constant value. I tried to find V2(t). C2V0 and C1V0 are initial conditions of capacitors.

The result I got with invlaplace makes no sense.

Thanks

1_Second-Order-RC-Laplace.zip

Electrical_Engineering

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Best answer by -MFra-

I have to make a small correction:

For Anselme 12.jpg

You can do even so:

For Anselme 123.jpg

L

LucMeekes

23-Emerald IV

Does this help:

(Note that the last expression runs further to the right. See attached Mathcad sheet.)

Success!

Luc

1_LM_20181002_Laplace.zip

A

Anselme

Author

1-Visitor

Thanks Luc,

But your sheet doesn't run in my MathCAD 15. see attached jpg

A

Anselme

Author

1-Visitor

Hi Luc,

I works, it was in manual calculation.

There is so many things I dont know about MathCAD...

At this point, you will not be surprised if I tell you that I am a little confused with your matrix solution.

Would you be kind enough to make a solution without matrix?

Your help is very appreciated.

-

-MFra-

21-Topaz II

Hi Anselme,

Allow me to point out you that the circuit you have drawn as the Laplace transform of the given network, however, contains an error. In fact the Laplace transform of a constant voltage L(V1) = V1/s, instead you wrote V1 which is the Laplace transform of a Dirac pulse of area V1. So if the voltage source is an independent and constant voltage generator, you have to correct the drawing and all the calculations.

Greetings