CIRCUITS CONTAINING CAPACITY. 



59 



Equation (6) shows that the current leads before the P.D. by an 

 angle, 0, given by 



tan = 4r 

 pCr 



and if the P.D. is given at any instant by 



E sin pt 



the corresponding current is given by 



E sin (pt + 9) 



JC' 



FIG. 19. 



Equation (6) may be changed into a current-vector equation, 

 thus 



^ = 



r 



pG 



