Common equipment and selection principles for multimeters
A digital multimeter is currently the most commonly used type of digital instrument. Its main features are high accuracy, strong resolution, complete testing functions, fast measurement speed, intuitive display, strong filtering ability, low power consumption, and easy portability. Since the 1990s, digital multimeters have rapidly become popular and widely used in China, becoming an essential instrument for modern electronic measurement and maintenance work, and gradually replacing traditional analog (i.e. pointer) multimeters.
Digital multimeters, also known as digital multimeters (DMMs), have a wide variety of types and models. Every electronics worker hopes to have an ideal digital multimeter. There are many principles for choosing a digital multimeter, and sometimes it may even vary from person to person. But for handheld (pocket sized) digital multimeters, they should generally have the following characteristics: clear display, high accuracy, strong resolution, wide testing range, complete testing functions, strong anti-interference ability, relatively complete protection circuit, beautiful and generous appearance, easy operation, flexibility, good reliability, low power consumption, easy portability, moderate price, etc.
Main indicators, display digits, and display characteristics of a digital multimeter
The display digits of a digital multimeter are usually 3 1/2 to 8 1/2 digits. There are two principles for determining the display digits of a digital instrument: firstly, the digits that can display all numbers from 0-9 are integer digits; The second point is that the value of the fractional digit is based on the highest digit in the maximum displayed value as the numerator. When measured at full range, the value is 2000, indicating that the instrument has 3 integer digits. The numerator of the fractional digit is 1, and the denominator is 2, so it is called 3 1/2 digit, which is read as "three and a half digits". The highest digit can only display 0 or 1 (0 is usually not displayed). The highest 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 has a 50% higher limit than a 3 1/2 digit digital multimeter, especially valuable for measuring 380V AC voltage.
Universal digital multimeters generally belong to handheld multimeters with 3 1/2 digit displays, while 4 1/2 and 5 1/2 digit (below 6 digits) digital multimeters are divided into handheld and desktop types. More than 6 1/2 digits are mostly desktop digital multimeters.
The digital multimeter adopts advanced digital display technology, with clear and intuitive display and accurate reading. It can ensure the objectivity of readings and conform to people's reading habits, which can shorten the reading or recording time. These advantages are not possessed by traditional analog (i.e. pointer) multimeters.
