Ques. What name is given to this method of testing?
Ans. It is called a zero method, distinguishing it from deflection methods.
Ques. For what kind of resistance is the method adapted?
Ans. Since it is a nil or zero method, it is better adapted to the measurement of non-inductive than of inductive resistances.
Ques. What precaution should be taken with inductive resistances?
Ans. The current must be allowed to flow until it becomes steady to overcome the influence of self-induction.
Ques. What may be said with respect to the differential galvanometer method?
Ans. With an accurate instrument it is very reliable.
Fig. 558.--Drop method of testing resistances. The apparatus is connected as shown and readings taken with voltmeter across known and unknown resistance. The unknown resistance is then easily calculated.