— r /t 2 



Resistance, and Self-Capacity of Magneto Windings. 79 



If T 2 is directly proportional to C we have 



C_o 

 'V 



and since R* is not zero L e is infinite, which is impossible. 

 This, however, does not occur actually, since the line through 

 the points obtained by plotting C and T 2 does not pass through 

 the origin. 



From (20) we obtain 



T 2 , aT /- R/r 2 



i 2 T fi.. K « T \ 



C 



Thus if T 2 /C is constant w T e must have approximately 

 (neglecting the intercept on the T 2 axis) 



=w«L r ( 



1 , R e 2 T 2 



1 + -t n 9 7 9. ) — a constant 

 lo7r"_Le 



= slope of line in fig. 3 of above paper. 



Thus if L e is assumed constant and found from the slope of 

 the line, as in Dr. Campbell's experiments, its value is 



approximately M + e . A times too large. Using the 



values of R e , co, and L e obtained previously, we find that 

 the above factor is 2*6. Hence the value of L 1} viz. 

 6"23xl0~ 3 henry as found by Dr. Campbell, is 2'6 times 

 too large. It appears, therefore, that in rinding the 

 inductance of a magneto by methods in which damped 

 oscillations are employed, the effective resistance of the 

 winding cannot be neglected. 



The effective inductance and the effective resistance can 

 also be obtained by varying the capacity in series with the 

 iron-cored cell, instead of varying the inductance. 



Using the same symbols as before, we obtain 



1 Re 2 



_L e Co 4L e 



0>T 



1 " L e C, 4L„ 2 ' 

 From (16) and (17) we find that 



0.-0! 1 



(22) 

 (23) 



L e 



nd _ o/^e 



R e = 2 1 ~ — a) 2 L e 2 j . 



