Explanation of the Meaning of Digital Multimeter Digits
There are two principles for determining the number of digits displayed on a digital instrument: one is that all digits from 0 to 9 can be displayed as integer digits; The second is that the value of the fractional digits is expressed as the numerator of the highest digit in the displayed value, and the denominator is expressed as the highest digit in the full range
For example, the maximum display value of a certain digital multimeter is ± 1999, and the full-scale count value is 2000, indicating that the instrument has 3 integer digits. The numerator of the decimal place is l and the denominator is 2, so it is called 3 1/2 digit, which is read as "three and a half digits". The high digit can only display 0 or 1 (0 is usually not displayed).
The high digit of the 3 2/3 digit (pronounced as "3 and 2/3 digits") digital multimeter can only display numbers from 0 to 2, so the maximum displayed value is ± 2999. In the same situation, it is 50% higher than the limit of 3 1/2 bit DMM, which is only ± 1999.
It should be pointed out that some people still refer to the 3 2/3 position instrument as the 3 1/2 position instrument, but it must be indicated that its limit has been expanded by 50% to avoid confusion between the two.
The high position of a 3 3/4 digit (pronounced as "three and three-quarters") digital multimeter can display numbers from 0 to 3, so the maximum display value is ± 3999, which is twice as high as that of a 3 1/2 digit instrument. Using a 3 3 3/4 digit digital multimeter to measure grid voltage has many advantages. For example, the second highest AC voltage range of a regular 3 1/2 digit DMM is 200V. If you want to measure 220V or 380V grid voltage, you must choose the high AC voltage range (usually 700V~750V range), which has a resolution of only 1V. In contrast, the second highest ACV range of a 3 3/4 digit DMM is 400V, which is suitable for measuring power frequency grid voltage. It is neither under range nor over range, and its measurement accuracy is better than the 700V range mentioned above. The resolution can be increased by 10 times, reaching 0.1V, which is the same as the 700V range resolution of the 4 1/2 DMM.
Universal digital multimeters generally belong to 3 1/2 digit instruments. There are two types of 4 1/2 digit multimeters: handheld and desktop. Most instruments with 5 1/2 digits or more belong to desktop intelligent digital multimeters.
Such as the German GMC multimeter product: METRAHet 30M nbsp; The reading of a 6 1/2 high-precision digital multimeter should be ± 1999999 (six and a half digits)
