.CHAPTER II 



8. Series arrangement of impedances 9. Parallel arrangement of impedances 

 10. Numerical example 11. Mutual inductance and its effects 12. Electro- 

 magnetic repulsion motor 13. Skin effect. 



8. Series Arrangement of Impedances 



LET two impedances, AB and BC, be connected in series as 

 shown in Fig. 12 (a), and let it be required to find their combined 

 impedance. 



An impedance is not completely specified by its numerical value. 

 For with the same numerical value of the impedance we may have 



widely differing values of the ratio , which determines the 



J resistance 



phase difference between e.m.f. and current. The impedance is, 



however, uniquely determined if in addition to the ratio - 



current 



we know the angle of phase difference between p.d. and current. 



Since the two impedances in Fig. 12 (a) are arranged in series 

 with each other, it follows that the current must have the same value 



PIG. 12. Two Impedances in Series. 



in each of them at every instant. For this reason, we choose the 

 current vector as our vector of reference in the vector diagram, and 







