What to Consider When Selecting a Digital Multimeter?
A multimeter is a multifunctional, multi range mechanical indicator meter composed of a measuring mechanism of a magneto electric meter and a rectifier. Can be used to measure AC and DC voltage, AC and DC current, and resistance.
Also known as a multimeter or a multimeter. Some multimeters also have functions such as measuring capacitance, inductance, etc. The multimeter is mainly composed of the measuring mechanism, measuring circuit, and conversion switch of the magneto electric meter.
Among them, the conversion switch is a switching element used by multimeters to select different measurement functions and ranges.
Digital multimeters are widely used in technical fields such as national defense, scientific research, factories, schools, and metrology testing due to their high accuracy, wide measurement range, fast measurement speed, small size, strong anti-interference ability, and easy use. However, their specifications are different;
There are various performance indicators, and the usage environment and working conditions also differ, so the appropriate digital multimeter should be selected according to the specific situation.
function
In addition to measuring AC and DC voltage, AC and DC current, resistance, and other five functions, modern digital multimeters also have functions such as digital calculation, self checking, reading retention, error reading, diode detection, word length selection, IEEE-488 interface or
RS-232 interface. When using them, they should be selected according to specific requirements.
accuracy
The maximum allowable error of a digital multimeter depends not only on its variable term error, but also on its fixed term error.
When choosing, it is also necessary to consider the requirements for stability error and linear error, and whether the resolution meets the requirements.
For general digital multimeters that require levels 0.0005 to 0.002, at least 61 digits should be displayed; Level 0.005 to 0.01, with at least 51 digits displayed;
Level 0.02 to 0.05, with at least 41 digits displayed; Below level 0.1, there should be at least 31 digits displayed.
Range and measuring range
A digital multimeter has many ranges, but its basic range has the highest accuracy. Many digital multimeters have automatic range adjustment function, which eliminates the need for manual range adjustment, making measurement convenient, safe, and fast.
There are also many digital multimeters that have over range capability. When the measured value exceeds the range but has not yet reached the maximum display, there is no need to change the range, thereby improving accuracy and resolution.
