Null Method

Any method of obtaining measurements or comparisons, in which the measurement is correct when the deflection of the galvanometer or other indicator is zero, nought or null. The Wheatstone Bridge (see Bridge) is an example of a null method.

Two obvious advantages attach to null methods in electric galvanometer work. One is that an uncalibrated galvanometer can be employed. The other is that a galvanometer of any high degree of sensitiveness can be employed, there being no restriction as to its fineness of winding or highness of resistance.

"Upper case Omega Graphic". (Greek capital" Omega") symbol for megohm. [Transcriber's note: Now used for ohms.]

"Lower case Omega Graphic". (Greek omega) symbol for ohm. [Transcriber's note: Now used for angular velocity, 2*PI*frequency.]