60 



TREATISE ON ALTERNATING CURRENTS. 



.ke . . . . (7) 



This is the current-vector equation, and is represented in 



Fig. 20, which shows the components of the current along and at 



right angles to the P.D. e. 



COMBINATION OF RESISTANCE, SELF-INDUCTION, AND CAPACITY 



IN SERIES. 



45. Consider a circuit consisting of a coil of wire, having 

 a resistance r, and self-induction Z, placed in series with a con- 

 denser of capacity C. Let an alternating P.D. e, of frequency n, 

 be applied between the extreme terminals of the circuit, and cause 

 an alternating current i to flow through it, and let p = 2vn. 



The P.D. must have a component ri in the direction of the 

 current, to drive the current against the ohmic resistance r, a com- 

 ponent TcpLi t to balance the E.M.F. Top Li of self-induction, and 



a component ^, to balance the E.M.F. + due to capacity. 



