Help: Graffeo Ex. 53

[applepieordie]

Hi,

My challenge is Ex. 53 d) of the Graffeo book, 2016 printing. see attached photo.

The part where he says "now square it to get rid of the j"

Why is it not (3Rg)^2 = (0.48-j0.38)^2 ??

am I an idiot? Im being serious.

View attachment 9713

 

[ptatohed]

Please post in the appropriate (Exam Prep) forum.  

 

[rg1]

Hi,

My challenge is Ex. 53 d) of the Graffeo book, 2016 printing. see attached photo.

The part where he says "now square it to get rid of the j"

Why is it not (3Rg)^2 = (0.48-j0.38)^2 ??

am I an idiot? Im being serious.

View attachment 9713

When we are stuck up in such situations we equate magnitude of impedances. This is actually he is doing. IZ1I =IZ2I. If it is not clear I will explain it in detail.

 

[rg1]

When we are stuck up in such situations we equate magnitude of impedances. This is actually he is doing. IZ1I =IZ2I. If it is not clear I will explain it in detail.

The following figure may make it clearer. 

View attachment 9716

 

[applepieordie]

The following figure may make it clearer. 

View attachment 9716

Thanks! Your explanation really helped.