Circuit equation

[ssato]

Hello everyone

I can not find the solution M of the attached equation. (mathcad 15)

[undefind] is displayed.

Please give some advice on what this means.

[LucMeekes]

Here's an example of circuit analysis with Mathcad:

(I generally first try to solve symbolically, afterwards I can fill in the numbers)

Success!
Luc

[ssato]

Hello Luc san

Thanks your quick response.

I can not solve  symbolically my problem.

I attached file.

[LucMeekes]

Hello Ssato san,

I cannot read your file directly,

Please save as Mathcad 11 .mcd file and attach.

(do not care about any warnings when saving).

Luc

[ssato]

Hello Luc san

I attached file saved by MATHCAD11.

[Werner_E]

According your file look at my previous answer - remove the symbolic eval after minerr.

According the last example in Luc's file, you may read the "error" message. There is no error, but Mathcad 15 simply is not able (or willing) to display the large result. Luc's Mathcad 11 uses a much more capable symbolic processor (Maple) and does not have this display problem.

But as the error message says, you still can USE the resulting function!

In this case with a little help from the "simplify" modifier we can even persuade MC to display the symbolic results one by one.

Note that in Luc's sheet ORIGIN is set to 1 and we unfortunately cannot use units when evaluating the functions numerically as the unit system is turned off in this sheet (-> Tools -> Worksheet Options -> Unit System)

[ssato]

Hello Werner_E san

 Thank you for your advise.

I understand ,I still can USE the resulting function.

[LucMeekes]

I think there's an error in your initial sheet: Unless R2 is 0, it's missing from the first equation.

In the sheet you adapted from mine, you included it as R1, I guess because it's meant to be non-zero.

Attached is my analysis of the circuit.

Success!
Luc

[ttokoro]

Prime 5 Loop method.

[LucMeekes]

Great!

But, the way you set it up, you don't need symbolics, and even Prime4 Express can solve it.

Luc

[ttokoro]

Thanks Luc.

 The answer of Node method is attached.

Tokoro.

[ssato]

Hollo Luc san

I'm sorry I mistake some parameter between diagram and equations.

[LucMeekes]

Hello Ssato san,

it's not that you named this resistor differently, it is even that I am mistaken about that. The problem is that this resistor is not in your formula.

I can find no part of your equations that represents this resistor.

Success!
Luc

[ssato]

Luc san

I'm so much sorry.

R1 in circuit diagram is not in equation.

I changed some reference number and equation.

Please check the attached file.

[AlanStevens]

Because your initial equations are linear in the currents, I1, I2 and I3, they can be rearranged in matrix form and solved as in the attached  (I first manipulated the equations a little before putting them into matrix form).

Alan

[ssato]

Alan san

Thank you for your response.

I understood your method.

[Werner_E · Accepted solution]

Simply don't use the symbolic evaluation after minerr

[ssato]

Hello Werner-E san

Thank you for your response.

What is it?....

 It was a rudimentary mistake.

[-MFra-]

Hi ssato,

Using the "direct network inspection" method. In my previous analysis, there was a mistake (I forgot to calculate a parallel) that now I've corrected.  (I renamed the passive and reactive components but the values correspond), and using the Minerr function in the solution block, I obtained these results :

[ssato]

Hello Topaz san

Thank you for your response.

Topaz

[-MFra-]

Hi ssato,

you will find the complete xmcd worksheet in my previous post.

It was fun. Many greetings, Francesco

[ssato]

Hello MFranc san

I'm intersted in your post. You solve without cicuit equations.

But it is difficult for me...

[-MFra-]

Hi Ssato,

the one I applied, in fact, is one of the most used procedures for small passive or active electrical networks. The generalized Ohm's law V (s) = Z (s) I (s) is applied.

Sincerely 

Franc

[ssato]

MFranc san

I will understand your method.

Thank you.