Select the Display Digits and Accuracy of Multimeters According to Requirements
Display digits and accuracy are two of the most fundamental and critical specifications of a multimeter. The two parameters are closely related. Generally speaking, the higher the display digits of a multimeter, the higher its accuracy, and vice versa. However, due to differences in measurement principles and quality standards among manufacturers, multimeters with the same digit count may feature different accuracy levels. For example, among 4½-digit multimeters, some models have an accuracy as high as 0.025%, while others only reach 0.8%.
There are two representation methods for display digits: count display and digit display. Count display is the actual representation of the multimeter's display range. For convenience of customary and traditional naming, digit display is commonly used instead. For instance, a 3000-count display means the maximum reading of the multimeter can reach 3999, whereas a 1000-count display can only reach 1999. When measuring 220 V AC voltage, you can clearly see that the 3000-count display has one extra decimal place compared with the 1000-count display, representing an order-of-magnitude higher resolution. High-resolution multimeters deliver greater performance in debugging and testing highly sensitive microelectronic signals.
Meanwhile, count display and digit display can be converted. Count the number of zeros in the count value, take the preceding number as the denominator of a fraction, subtract 1 from this number as the numerator, and the resulting fraction is the digit specification. For example, a 3000-count meter corresponds to a 3⅔-digit display. Some currently available handheld multimeters achieve a count display up to 500000 counts.
