440 H. A. Rowland — Electrical Measurement. 



Method 12. 

 L' R + R' 



Should the circuits R and r also have small self inductances, 

 L and I, we can use the exact equation 



Lr 



T , T r+r' 1 + m; R+R' 7 r L? * h ^ 1 ~i 



L + L = l [? T 7 = l\ 1+ m + -5-+etc. 



r tfhl r L IR rR J 



1 ~7r 



When 1/ and Z are approximately known, we can write the 

 following, using the approximate value on the right side of the 

 equation 



L' _ R + R' f Lr L' r b*U 



f-^r L 1+ m~TR + Br + 7R +etC * 



Taking out L' and putting a condenser, C, in K we have 



I = rR' - WCB,(R + R') 

 For a condenser, R can be small or zero. 



Method 13. 



(A) [_^L - ^J _ R ^- 



This determines capacities or self inductions in absolute 

 value. As described above, mutual induction can also be de- 

 termined by converting it into self induction. 



fm[~»T 1 I'.. [R"B i -R'B„] [R„(r + R,) + B,(r + R")] 



(B) |_»L, - gg- J - - R'(r + R ( ) 



,™ r hl i f_ rR , R,-R"R,][R,('-+R /, )+R»('-+ R .)] 



(C) L ~WJJ ~ R"[r + R" + R„] 



Method H. 



C'J 



[R,R" -R„R'] [r[R' + R ; + R" + R„] + [R' +R,][ R" + R„] ] 

 R„[r+R" + R„r 



* L '- JC 



Of course, in any of these equations, methods 13 or 14, L" 

 is eliminated by making L" = or the condenser, C, is omit- 

 ted by making C = go . 



