I'M 



BELL SYSTEM TECHNICAL JOURNAL 



The total series "loop" impedance of the pair of loaded conductors 

 per centimeter is Z = Zi -\- Xo-^ 



For the purpose of indicating the degree of precision of the approxi- 

 mate formula, data are given in Fig. 2 on the internal resistance and 

 inductance of various copper wires coated with loading material to 



300 



250 



tf) 



I 



200 



a. 

 us 

 a. 



LU 



o 

 z 

 < 



in 



IS) 

 LU 



a. 



(0 0.0248 



> 

 a. 



z 



UJ 0.0246 



uj 0.0244 



_1 



cc 



LU 



a 



ai 

 o 

 z 

 < 

 I- 

 o 



D 



a 



z 



0.0242 



0.0240 



0.0238 

 O0236 



4 6 8 



FREQUENCY — KILOCYCLES 



10 



12 



pi^_ 2 — -Internal impedance of wires of various sizes with continuous loading ol 



approximately 25 millihenrys per wire mile (for very small currents, 



i.e., hysteresis losses not included). 



3 All quantities are expressed in the electromagnetic c.g.s. system of units. To 

 obtain the result in ohms per loop mile, multiply by 160,934 (10~»j. In the case 

 of cable circuits, A'2 ( = zcoL22) is an experimentally determined quantity, L22 having 

 a value of about .001 henry per mile. 



