Galvanometer for Alternate Current Circuits. 315 



All these methods may be used with the present instru- 

 ment for steady inductive balances on alternate current 

 circuits, and the same formulae apply to the zero deflexion 



M/WWV~M/WW\H 



M 



11, + r, ~B, 2 + r a 



Fiff. 6. 



M 



771.C. 



H/WWV 



R K 



M 



R-4-r 



= KS. 



Fig. 7. 



L r 



■sisis^ 



711. C. 



A/WWV— 



>- Lj vwwv- 1 



R 



KS = 



R-f-i 



condition, provided (i.) the alternate voltage V applied to the 

 field-coil of the instrument also causes the current A through 

 the bridge conductors, (ii.) the alternate current A is made 

 essentially cophasal with V by the use of suitable non- 



Y2 



