124 W. M. Stine — Simple Compensated Shunt Box. 



Art. XYII. — Simple Compensated Shunt Box; by Wilbur 



M. Stine. 



The usual method to compensate for the shunting of a 

 galvanometer that the resistance of the circuit may remain 

 unaffected by the introduction of the shunt, is to insert in series 

 with the galvanometer in succession certain auxiliary or com- 

 pensating resistances. 



If the resistances of the various shunts to the galvanometer 

 be denoted by S n S 2 , S 3 , . . . , the multiplying factors by n x , 

 n»n % , . . . , taken in the order of their descending values, and 



the compensating resistance by ?\, r 2 , r s , : a set of 



defining equations may be given to the usual method for com- 

 pensation. These equations are, for a galvanometer of resist- 

 ance, g, 



S=— ^- (1) 



s ___ rc>,-0 /„x 



'-'* *>.-!)' () 



a _ „ M,K-1) /ox 



^-d-^—.y (3) 





W 



and 



r, + r, = ff ( "/ "'}. (5) 



r 1 + r t +r t =g-^— (6) 



According to the usual practice, n x , n„ n s have the respective 

 values, 1000, 100 and 10, and the preceding equations readily 

 reduce to constant relations, thus — 



S, =#xo-ooiooi 



S 9 = ,?X 0-010 193 

 S 3 = #X0-1233 

 and 



r x = gX 0-00909 

 r 2 = ^XO-100909 

 r s =gx 0889 



The foregoing equations are obtained only by long and 

 tedious algebraic processes, and it is readily apparent that their 

 final values are such as to throw doubt on the accuracy of the 

 adjustment of a box. 



