What each digit on a digital multimeter means
There are two principles for judging the display digits of digital instruments: one is that the digits that can display all numbers from 0 to 9 are integer digits; The highest digit at full scale is used as the denominator.
For example, the maximum display value of a digital multimeter is ±1999, and the full-scale count value is 2000, which indicates that the instrument has 3 integer digits, and the numerator of the fractional digit is l, and the denominator is 2, so it is called 3 1/ 2 bits, read as "three and a half digits", the highest bit can only display 0 or 1 (0 is usually not displayed).
3 2/3 digits (pronounced "three and two-thirds digit") The highest digit of a digital multimeter can only display numbers from 0 to 2, so the maximum display value is ±2999. Under the same conditions, it is 50% higher than the limit of a 3 1/2-digit DMM, which is only ±1999.
It should be pointed out that some people still refer to the 3 2/3-digit meter as the 3 1/2-digit meter, but it must be indicated that its measurement limit has been extended by 50%. so as not to confuse the two.
3 3/4 digits (pronounced "three and three-quarters") The highest digit of a digital multimeter can display numbers from 0 to 3, so the maximum display value is ±3999, and its limit ratio is 3 1/2 digits Twice as high. Using a 3 3/4-digit digital multimeter to measure grid voltage has many advantages. For example, the second-highest AC voltage block of a common 3 1/2-digit DMM is 200V. If you want to measure 220v or 380v grid voltage, you must select The highest AC voltage gear (usually 700v~750v gear), the resolution of this gear is only 1v. In contrast, the next highest ACV gear of 3 3/4 digit DMM is 400V, which is most suitable for measuring power frequency grid voltage, neither The measurement range is not over the range, and its measurement accuracy is better than the above 700v block, while the resolution can be increased by 10 times to 0.1v, which is the same as the 700V block resolution of 4 1/2 digit DMM.
Popular digital multimeters are generally 3 1/2-digit instruments. There are two types of 4 1/2-digit digital multimeters: hand-held and desktop. Most of the instruments with 5 1/2 digits and more than 5 1/2 digits are desktop intelligent digital multimeters.
