56 TRKATTSE ON ALTERNATING CURRENTS. 



since Jc 2 = 1 



. e _ PL fc _ _ (3) 



which is a current- vector equation, and states that the current / 

 can be resolved into a component 



parallel to the direction of e, that is, in phase with e, and a 

 component 



pi , j . 

 *' 



at right angles to the direction of e, and lagging behind it. This 

 is shown graphically in Fig. 18, where OP is the current vector, 



and OQ and QP its components respectively along and at right 

 angles to the direction of e. It should be noticed that the 

 product 



(r + lyL)(r - kpL) 

 which equals 



since k = - 1, is not a vector product ; the quantities r t p, and Z 

 are all scalar, and must not be treated as vectors. 



