Electric Circuit Analysis

Phasor Diagrams    7.41

I

S

I

L

I

C

I

R

V

–

+

j8 Ω

–j4 Ω

6 Ω

5∠–45° A

I

S

I

L

I

C

I

L

I

R

1.5 d

d

V

0.75 d

Fig. 7.8-7 Circuit and phasor diagram in Example 7.8-4 

We have set I

R

in the horizontal direction. This does not mean that i

R

(t) will be a cos100pt wave.

Once we solve the phasor diagram completely, the source current phasor will come out with some

angle other than its actual angle of –45°. Then we will rotate the entire phasor diagram such that I

S

takes up –45° position in the diagram. The other phasors will then take up suitably shifted positions.

The new angular positions can be calculated from the known angular position of I

S

and apparent

angular position ...