Hello,

I was just wondering if someone could please check my maths and show me where I went wrong...

Im trying to find the total add admittance of this circuit:

http://www.flickr.com/photos/41254456@N05/3807839423/

So far I have:

Y = (1 / 2<0°) + (1 / 2.5<-90°) + (1 / 1.41<45°)

Multiplying across by

(2<0°)(2.5<-90°)(1.41<45°) / (2<0°)(2.5<-90°)(1.41<45°)

Yeilds :

Y = (2.5<-90°)(1.41<45°) + (2<0°)(1.41<45°) + (2<0°)(2.5<-90°)

Y = (3.53<-45°) + (2.82<45°) + (5 < -90°)

Converting to cartesian format =

2.5 - 2.5i + 1.99 +1.99i - 5i

= 4.49 - 0.51i = 4.52 < -6.48° = Y.

This is fine and grand, however if I just get the reciprocals and sum them :

Y = (1 / 2<0°) + (1 / 2.5<-90°) + (1 / 1.41<45°)

Y = (0.5<0°) + (0.4<90°) + (0.71<-45)

= 0.5 + 0.4i + 0.5 -0.5i

Y = 1 - 0.1i = 1 < 5.71°

These two answers are completely different, shouldn't they be the same?

Or have I gone wrong with my math somewhere?

Ive tried this like 3 time and got the same answers each time.

Any help is massively appreciated...

I was just wondering if someone could please check my maths and show me where I went wrong...

Im trying to find the total add admittance of this circuit:

http://www.flickr.com/photos/41254456@N05/3807839423/

So far I have:

Y = (1 / 2<0°) + (1 / 2.5<-90°) + (1 / 1.41<45°)

Multiplying across by

(2<0°)(2.5<-90°)(1.41<45°) / (2<0°)(2.5<-90°)(1.41<45°)

Yeilds :

Y = (2.5<-90°)(1.41<45°) + (2<0°)(1.41<45°) + (2<0°)(2.5<-90°)

Y = (3.53<-45°) + (2.82<45°) + (5 < -90°)

Converting to cartesian format =

2.5 - 2.5i + 1.99 +1.99i - 5i

= 4.49 - 0.51i = 4.52 < -6.48° = Y.

This is fine and grand, however if I just get the reciprocals and sum them :

Y = (1 / 2<0°) + (1 / 2.5<-90°) + (1 / 1.41<45°)

Y = (0.5<0°) + (0.4<90°) + (0.71<-45)

= 0.5 + 0.4i + 0.5 -0.5i

Y = 1 - 0.1i = 1 < 5.71°

These two answers are completely different, shouldn't they be the same?

Or have I gone wrong with my math somewhere?

Ive tried this like 3 time and got the same answers each time.

Any help is massively appreciated...

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