122 SINGLE-PHASE CURRENTS. [Exp. 



fundamental harmonics with frequencies higher than the fun- 

 damental. 



61. In inductive circuits, reactance increases with frequency. 

 Inductive reactance is, accordingly, greater for these harmonics than 

 for the fundamental ; harmonics in the current are choked out and 

 the current wave is more nearly a sine wave than is the wave of 

 impressed electromotive force. For this reason, vector diagrams 

 can be used for representing experimental results, obtained from 

 measurements on inductive circuits, without much error even when 

 the impressed electromotive force is not a true sine wave. 



62. Capacity reactance, on the other hand, decreases with fre- 

 quency and harmonics in the current are, accordingly, augmented; 

 hence, a small distortion in the electromotive force wave may make 

 a large distortion in the current wave. 



63. For this reason, vector diagrams are less accurate for rep- 

 resenting experimental results for capacity circuits than for inductive 

 circuits, when the electromotive force is not a true sine wave. For 

 example, in the laboratory without special precautions, capacity react- 

 ance can not be measured by alternating current methods as accu- 

 rately as inductive reactance. 



64. When capacity and inductance are both present, a small dis- 

 tortion in the electromotive force wave may be much exaggerated 

 by the resonance of a particular harmonic, with corresponding error 

 in any vector representation. 



