HARMONIC ELECTROMOTIVE FORCE AND CURRBNT. 65 



the component, / sin 0, which is at right angles to E is some- 

 times called the wattless component of the current. 



It is more legitimate, physically, to speak of a wattless electro- 

 motive force than it is to speak of a wattless current. Thus, the 

 rate at which heat is generated in a circuit by a harmonic current 

 is RP, and this is equal to R x (power component of /)* plus 

 R x (wattless component of 7) 2 . That is, there is no such thing, 

 physically, as a wattless current in a circuit which has resistance, 

 although a given current may be resolved into two components 

 as shown in Fig. 56, and the component / sin 6 does not receive 

 power from tlie generator. 



