Finding R and C from a parallel RC circuit

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Discussion Overview

The discussion revolves around determining the resistance (R) and capacitance (C) values in a parallel RC circuit given its impedance and frequency. Participants are exploring the mathematical relationships and calculations necessary to extract these values from the provided information.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant presents the impedance of a parallel RC circuit as Z = 105000 Ω ∠ -27 and expresses confusion about how to proceed after converting the impedance to a rectangular form.
  • Another participant suggests calculating 1/Z and expressing it in a + jb form, indicating that the real and imaginary parts can be compared to find R and C.
  • A participant shares their calculation of 1/Z, resulting in a complex number, but expresses uncertainty about how to derive R and C from this result.
  • There is a suggestion to equate the terms of the expression to the numerical values of the conductance components, indicating a method to find R and C.

Areas of Agreement / Disagreement

Participants are generally aligned on the approach of using the impedance formula and comparing real and imaginary parts, but there remains uncertainty about the specific steps to extract R and C values from the calculations.

Contextual Notes

Participants have not fully resolved the mathematical steps necessary to find R and C, and there may be missing assumptions regarding the definitions of the components involved.

Agent47
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Homework Statement



A RC parallel circuit with an impedance of Z = 105000 Ω ∠ -27 and frequency of 50 Hz.

Homework Equations



I need to find out what the R and C values using the information given.

The Attempt at a Solution



I know the impedance for a parallel RC can be calculated from

1/Z = 1/R +jwc

Z can be converted to Z = 9355.69 -j47669 but from there i am completely confused on what to do next.

Any help will be much appreciated.
 
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Well you can calculate 1/Z and express it in a+jb form...Compare the real and imaginary parts then.
 
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If i do 1/z i would get,

0.000008485 +j0.000004323

but I am still not sure where R and C would come from.
 
Agent47 said:
I know the impedance for a parallel RC can be calculated from

1/Z = 1/R +jwc

Agent47 said:
If i do 1/z i would get,

0.000008485 +j0.000004323

but I am still not sure where R and C would come from.

[scientific notation would help curtail all those zeros :smile:]

Equate the terms of your expression above to the numerical values of the conductance components...
 
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I want to thank you both for your help.
 

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