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Circuit equation

ssato
14-Alexandrite

Circuit equation

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.

1 ACCEPTED SOLUTION

Accepted Solutions
Werner_E
24-Ruby V
(To:ssato)

Simply don't use the symbolic evaluation after minerr

B.png

View solution in original post

23 REPLIES 23
LucMeekes
23-Emerald III
(To:ssato)

Here's an example of circuit analysis with Mathcad:LM_20190726_Circuit.png

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

Success!
Luc

ssato
14-Alexandrite
(To:LucMeekes)

Hello Luc san

 

Thanks your quick response.

 

I can not solve  symbolically my problem.

 

I attached file.

LucMeekes
23-Emerald III
(To:ssato)

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
14-Alexandrite
(To:LucMeekes)

Hello Luc san

 

I attached file saved by MATHCAD11.

 

Werner_E
24-Ruby V
(To:ssato)

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)

B.png

ssato
14-Alexandrite
(To:Werner_E)

Hello Werner_E san

 

 Thank you for your advise.

I understand ,I still can USE the resulting function.

 

LucMeekes
23-Emerald III
(To:ssato)

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.

 

LM_20190726_CircuitEquation1.png

LM_20190726_CircuitEquation2.png

Success!
Luc

ttokoro
20-Turquoise
(To:LucMeekes)

Prime 5 Loop method.

LucMeekes
23-Emerald III
(To:ttokoro)

Great!

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

Luc

ttokoro
20-Turquoise
(To:LucMeekes)

Thanks Luc.

 The answer of Node method is attached.

Tokoro.

ssato
14-Alexandrite
(To:LucMeekes)

Hollo Luc san

 

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

 

LucMeekes
23-Emerald III
(To:ssato)

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.

LM_20190729_Circuit.png

 

Success!
Luc

ssato
14-Alexandrite
(To:LucMeekes)

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.

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
14-Alexandrite
(To:AlanStevens)

Alan san

 

Thank you for your response.

I understood your method.

 

 

Werner_E
24-Ruby V
(To:ssato)

Simply don't use the symbolic evaluation after minerr

B.png

ssato
14-Alexandrite
(To:Werner_E)

Hello Werner-E san

 

Thank you for your response.

 

What is it?....

 It was a rudimentary mistake.

 
-MFra-
21-Topaz II
(To:ssato)

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 :

network 222.jpgnetwork 223.jpgnetwork 224.jpgResults 1.jpgResults 2.jpg

 

ssato
14-Alexandrite
(To:-MFra-)

Hello Topaz san

 

Thank you for your response.

 

Topaz
-MFra-
21-Topaz II
(To:ssato)

Hi ssato,

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

Results 1.jpg

Results 2.jpg

It was fun. Many greetings, Francesco

ssato
14-Alexandrite
(To:-MFra-)

Hello MFranc san

 

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

But it is difficult for me...

 

-MFra-
21-Topaz II
(To:ssato)

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
14-Alexandrite
(To:-MFra-)

MFranc san

 

I will understand your method.

Thank you.

 

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