Null Meter

An electrically operated instrument having a zero point on its scale (usually located in the center thereof). It may not indicate units of electrical measurement. The value may be expressed by means of a pointer and calibrated dial or a digital readout display. When the indication shows zero, an electrical value of "zero" has been reached in the circuit. It is generally used in situations in which zero is the desired effect. Excludes ammeter, galvanometer; meter, arbitary scale; and voltmeter.