THE ALTERNATOR. 27 



when these large slots come under the pole pieces, and in this 

 case the pulsations of flux tend to modify the shape of the elec- 

 tromotive force curve, making it like the curve e of Fig. 26. 



Examples of current curves. When an alternating electromo- 

 tive force acts upon a circuit which contains resistance only, that 

 is, a circuit which has a negligibly small inductance and which 



8 



Axis of time 



Fig. 24. 



Axis of time 



does not include a condenser, the current curve is of exactly the 

 same shape as the electromotive force curve, inasmuch as the 

 current is in this case equal at each instant to the electromotive 

 force divided by the resistance of the circuit. 



When an alternating-current circuit has an appreciable induct- 

 ance (ironless), or when it contains a condenser, the current curve 



