ARTIFICIAL ELECTRIC LINES WITH MUTUAL INDUC- 

 TANCE BETWEEN ADJACENT SERIES ELEMENTS. 



By George W. Pierce. 



Received Jan. 13, 1922. ' Presented Jan. 11, 1922. 



L General Principles. 



1. Introduction. — So far as I have been able to ascertain, the 

 artificial lines with lumped sections heretofore employed have been 

 generally devoid of appreciable mutual inductance between adjacent 

 elements. 



In artificial line construction the inductive elements are placed 

 mutually at right angles to each other or are wound in toroidal form 

 so as to reduce to a minimum the mutual inductance caused by 

 magnetic leakage from one inductive element to the next. 



In my Text Electric Oscillations and Electric Waves,^ Chapter XVI, 

 I have treated theoretically artificial lines in which mutual inductance 

 exists between adjacent series elements. 



It is proposed here to show, with the aid of the general treatment in 

 my text, that such mutual inductance, if properly chosen, has a de- 

 cidedly beneficial effect in the following two types of apparatus: 



A. An Electric Compensator designed to introduce into circuits a 

 time lag substantially independent of the frequency of impressed 

 e.m.f.; 



B. An Artificial Line designed to simulate an actual smooth line.^ 



2. General Type of Line. — Let us direct our attention to the 

 general type of artificial line shown in Figure L 



The shunt elements of complex impedance Zo may be of any charac- 

 ter. The series elements of complex impedance Zi may likewise be of 

 any character, and have between such of these elements as are adja- 



1 Pierce: Electric Oscillations and Electric Waves, McGraw-Hill Book Co., 

 New York, 1920. (See also corrected reprint in press 1921.) 



2 Since sending this paper to press I have been informed by Mr. K. S. 

 Johnson that application of the present device in Case B has been in use for 

 several years at the Western Electric Company, but has not been described in 

 publications. 



