Pupin — Resonance Analysis of Alternating Currents. 381 



ler number of its sections into the circuit. The resistance can 

 be varied by a rheostat f Suppose now that the self-induction 

 of c is kept constant, and that the capacity of the condenser d 

 is gradually increased from zero up. Whenever a capacity has 

 been reached which with the self-induction of the circuit acdfb 



23roduces resonance with one of the harmonics in the main cir- 

 cuit then the resonant rise of potential will produce a large 

 deflection in the voltmeter. In this manner all the harmonics 

 which are present in the current of the main circuit can be 

 detected in the course of a few minutes. If the resonator cir- 

 cuit acdfb is placed in shunt with the non-self-inductive cir- 

 cuit g (this circuit is represented in fig. l a by a line beaded 

 with asterisks and running from one pole of the alternator to 

 the other) consisting of a bank of incandescent lamps then the 

 harmonics of the impressed electromotive force can be detected 

 in the same manner. The ratio of the amplitudes of these har- 

 monics to that of the fundamental can also be determined by this 

 method, if desirable, provided the conditions of the experiment 

 are properly arranged. For let the current in the main circuit be 



x=a t sin^ + a 3 sin 3pt + + a 2a+l sin(2tor + l)pt-\- . . 



then the drop between a and b can be represented by 

 e=b t mnpt + .... + b 2a + \ sin (2a + l)pt + . . . 

 where b 2a + l = a 2a+l r 



and r = ohmic resistance between a and b. Denoting now by : 

 L the self-induction of the resonator acdfba 

 R the resistance " " " 



C the capacity " " " 



