Final answer:
The incomplete statement likely refers to 'auto-ranging' meters, which are digital meters that automatically select the appropriate measurement scale. These meters are convenient and accurate, with some employing null measurements for high precision.
Step-by-step explanation:
The statement that a digital meter which automatically selects the appropriate scales is described as blank is not fully clear or complete. It seems to be referencing a characteristic of some digital meters, but 'blank' is not descriptive of any feature. Digital meters that do not require manual selection of scales because they automatically adjust to measure different parameters are often referred to as auto-ranging or autoranging meters. These meters are convenient because they simplify the process of measuring electrical quantities such as voltage, current, and resistance by self-selecting the appropriate range. They are contrasted with manual meters, which require the user to select the correct measurement range.
It is worth mentioning that digital meters can also employ null measurements, a technique that involves drawing no current, thereby not altering the circuit being measured. This approach can achieve high accuracies, sometimes up to one part in 106. In contrast to analog meters with a moving needle and based on a galvanometer, digital meters using solid-state electronics can detect smaller currents and are typically more accurate.