Introduction of measuring range and measuring rate of digital multimeter
Measuring range
In a multi-function digital multimeter, different functions have their corresponding maximum and minimum values that can be measured.
measurement rate
The number of times a digital multimeter measures the measured electricity per second is called the measurement rate, and its unit is "times/s". It mainly depends on the conversion rate of the A/D converter. Some handheld digital multimeters use the measurement period to indicate the speed of measurement. The time required to complete a measurement process is called the measurement cycle.
There is a contradiction between the measurement rate and the accuracy index. Usually, the higher the accuracy is, the lower the measurement rate is, and it is difficult to balance the two. To solve this contradiction, you can set different display digits or set the measurement speed conversion switch in the same multimeter: add a fast measurement file, which is used for the A/D converter with a faster measurement rate; To increase the measurement rate, this method is relatively common and can meet the needs of different users for the measurement rate.
Introduction to the main indicators, display digits and display characteristics of digital multimeters
The display digits of a digital multimeter are usually 3 1/2 to 8 1/2 digits. 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 numerator is the numerator, and the count value is 2000 when the full scale is used, which indicates that the instrument has 3 integer digits, and the numerator of the fractional digit is 1, and the denominator is 2, so it is called 3 1/2 digits, 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 the 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 digital multimeter, which is especially valuable when measuring 380V AC voltage.
Popular digital multimeters generally belong to handheld multimeters with 3 1/2 digits display, and 4 1/2, 5 1/2 digits (less than 6 digits) digital multimeters are divided into handheld and desktop. More than 6 1/2 digits mostly belong to desktop digital multimeters.
The digital multimeter adopts advanced digital display technology, with clear and intuitive display and accurate reading. It not only ensures the objectivity of the reading, but also conforms to people's reading habits, and can shorten the reading or recording time. These advantages are not available in traditional analog (ie pointer) multimeters.
