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ssato15-Moonstone
15-Moonstone
September 24, 2019
Solved

Resonance frequncy 2

  • September 24, 2019
  • 13 replies
  • 4574 views

みなさん、こんにちは

 

 再び共振周波数についての質問です。

添付ファイルを確認してください。

 

1. w2bとw4bの正しい周波数が見つからないのはなぜですか？

 

2. w2x（w2y）とw2a（w2c）は等しくありませんが、正しいですか？

  また、w4x（w4y）およびw4a（w4c）。

 

3. R2 = 1mohm（1ohmではない）の場合、上記の2つの周波数は等しくなります。

 さらに、それぞれw2とw4に等しくなります。

 R1でこれが異なるのはなぜですか？

 

4.共振周波数は一般的に次のうちどれですか？

  （1）最大/最小インピーダンス

  （2）虚数部= 0（引数= 0）

 

これらのうち、3と4はMATHCADに関する質問ではありませんが、誰もが知っている場合はお知らせください。

 

Best answer by Werner_E

I would like to second what Francesco wrote about using common nomenclature. I changed some of it in the attached worksheet.

According your solve blocks not finding the correct solution, the reason is the guess values. Those equations seem to be quite sensitive wrt guesses, Changing the guesses in the right direction makes the solve block work. Using a plot can help to find a suitable guess.

Hope the attached sheet helps

13 replies

F
Ferrell8881-Visitor
1-Visitor
September 24, 2019
@ssato wrote:

Hello everyone

 

 It is a question about the resonance frequency again.

Please check the attached file.

 

1. Why can't I find the correct frequency for w2b and w4b?

 

2. Is w2x (w2y) and w2a (w2c) not equal, but is it correct?

  Also w4x (w4y) and w4a (w4c).

 

3. When R2 = 1mohm(not 1ohm), the above two frequencies are equal.

 Furthermore, it becomes equal to w2 and w4 respectively.

 Why is this different in R1?

 

4. Which of the following does the resonance frequency generally mean?

  (1) Maximum / minimum impedance

  (2) Imaginary part = 0 (argument = 0)

 

Of these, 3 and 4 are not questions about MATHCAD, but if anyone knows, please let me know.

 

OK.

-
-MFra-21-Topaz II
21-Topaz II
September 24, 2019

Hi ssato,

 I would like to suggest you to use the common way to write, with the use of MATHCAD, the units of measurement and the variables in Greek, IE: a microfarad is written 1 m control g F, that is 1μF; omega is written so: w CTRL g, that is ω. 

Regards

FM

W
Werner_E25-Diamond IAnswer
25-Diamond I
September 24, 2019

I would like to second what Francesco wrote about using common nomenclature. I changed some of it in the attached worksheet.

According your solve blocks not finding the correct solution, the reason is the guess values. Those equations seem to be quite sensitive wrt guesses, Changing the guesses in the right direction makes the solve block work. Using a plot can help to find a suitable guess.

Hope the attached sheet helps

    S
    ssato15-MoonstoneAuthor
    15-Moonstone
    September 24, 2019

    Hello Werner_E san

     

    Thank you for your response.

     

    I understand that the guess value is important.
    I also understand that the estimated value is determined from the graph.

    However, does it mean that the position of the solution on the graph and
    the estimated value are not always the right or left?
    S
    ssato15-MoonstoneAuthor
    15-Moonstone
    September 24, 2019

    Hello Werner_E san

     

    I wrote another one point in your attached file.

     

    Normally, it seems that the resonance frequency is defined as the frequency
    at which the imaginary part becomes zero.
     
    In a simple LCR resonant circuit, the impedance becomes maximum / minimum at the same frequency.
     
    When R2 is 1mΩ in this circuit, these two frequencies are equal within the range of effective digits,
    but clearly not equal when R2 is 1Ω.
     
    I wanted to ask those who understand this intuitive explanation.

     

     

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