AC Circuits question verification

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Discussion Overview

The discussion revolves around the verification of an equation related to AC circuits, specifically the impedance calculation involving reactance values. Participants analyze a tutorial video and question the correctness of the equation presented.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant questions the equation presented in a video tutorial, noting a discrepancy in the use of reactance values (Xc and XL).
  • Another participant asserts that the equation Xl - Xc is correct and explains that squaring the difference yields the same result regardless of the order.
  • A different participant emphasizes that the equation should reflect the difference between XL and XC, suggesting that the order does not affect the outcome.
  • One participant points out that conventionally, XL is treated as positive and XC as negative in these calculations.
  • A later reply confirms the equation used in the video is correct but suggests that the presenter may have made a simple error in their working.

Areas of Agreement / Disagreement

Participants express differing views on the correctness of the equation used in the video, with some asserting it is correct and others suggesting there may be an error. The discussion remains unresolved regarding the implications of the order of reactance values.

Contextual Notes

There is a lack of consensus on whether the presenter's working contains an error, and the discussion highlights the importance of conventions in defining reactance values.

Yarnzorrr
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Hi there,

in this youtube tutorial about AC circuits

http://www.youtube.com/watch?v=JiLdrAHBBRc&feature=plcp

at about 4:08 It's supposed to be z=√(R^2+(XL-Xc)^2)) but in the example she does Xc-XL, is there a reason for this or is it a mistake in her working??
 
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Xl - Xc is correct. In her example she has (Xc - Xl)^2. When she squares the difference, the result is the same.
 
The equation should be written
Z = √(R^2 +(XL ~XC)^2)
because it is the difference between XL and XC that is important. It does not matter which is greater.
 
In this equation that's true but generally Xl is regarded as positive and Xc as negative.
 


Hello there,

Thank you for bringing this to my attention. After reviewing the video, I can confirm that the equation used is correct. The mistake in the working is most likely a simple error made by the presenter. It is important to always double-check equations and calculations in order to avoid these types of mistakes. Thank you for verifying the information and bringing it to my attention.
 

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