Lov) Frequency and their Resonance. 507 



E . 



(x) = = sin pt 



{y) = ; L y (-) 



0Y) - o J 



as it should be. 



The curves given in fig. 1, fig. 2 hold true in this case also 

 but with this characteristic difference that for all variations of 

 S between and a considerably large limit (especially if E, is 

 very small, as in the case of Tesla's high frequency circuits) 

 the secondary current and secondary potential are practically 

 constant. The higher the frequency the larger is this limit. 



More than ordinary interest is attached to the relations given 

 in (10°), because they give an approximately correct account 

 of the electrical flow in the secondary circuit of an induction 

 coil when the primary is excited by a Tesla high frequency 

 alternator, the primary coil of the induction transformer, a 

 condenser of suitable capacity and the alternator being con- 

 nected in series. It must be observed, however, that since in 

 general the induction coil which Mr. Tesla employs in his 

 experiments does not differ essentially from the ordinary induc- 

 tion coil except that practically no iron is used — it is evident 

 that the secondary coil has distributed capacity which if not 

 necessarily as large as the capacity which would bring this cir- 

 cuit in resonance to the impressed e. m. f. at Mr. Tesla's high 

 frequencies is certainly far from being negligibly small in com- 

 parison to it. For this reason equations (10 a ) do not give the 

 exact mathematical relations of Mr. Tesla's circuits. It is evi- 

 dent, however, that the values which these equations assign to 

 the secondary current and secondary potential are the largest 

 values which Mr. Tesla's circuits can possibly yield. 



I do not find a single discrepancy between the theory just 

 given and Mr. Tesla's experimental results. A full discussion 

 of these results from the standpoint of this theory would lead 

 me far beyond the limits of this paper. A few brief observa- 

 tions relative to the agreement between theory and Mr. Tesla's 

 experiments* seem desirable : 



a. On account of the considerable internal capacity of Mr. 

 Tesla's induction coils there is a critical speed of the generator 

 at which a large secondary coil by its own internal capacity 

 will be in resonance to the impressed e. m. f. If it is desira- 



* See Mr. Nikola Tesla's lecture in the N. Y. Electrical World, vol. xviii, July 

 11, 1891, p. 20. 



Am. Jour. Sci. — Third Series, Vol. XLV, No. 270. — June, 1893. 

 35 



