How to choose a multimeter based on accuracy and number of bits?

With the development of electronic technology, digital multimeters are increasingly used in our daily life and work because of its intuitive display and convenient reading. A good digital multimeter can not only measure various electrical parameters, but also be an effective assistant for electronic enthusiasts to troubleshoot and repair electrical appliances.

There are many types of digital multimeters currently available for selection. Choose a digital multimeter that is both affordable and meets your needs. The accuracy and number of digits of the multimeter are the key points!

Resolution
Resolution refers to the ability to resolve small signals when the multimeter is measured. If the resolution of the digital multimeter within the specified range is 1mV, you can see a small change of 1mV when measuring the signal.

Number of digits and number of words
The so-called digits refer to the three and a half digits we often say, three and a half digits, that is, four digits, three of which refer to ten digits that can display 0-9 in the last three digits, called the full digit. The first digit on the left is displayed as 1 (the blanking is less than 1). This bit can theoretically display 2, for example, in 2V, the maximum display should be 2000, but it actually shows 1999. Then the theoretical value should show 2 at most, but only 1 can be displayed, which is called 1/2 bit. The theoretical value is the denominator, and the actual display is the maximum. The same is true for 4 and a half and 5 and a half.

Three and a half, that is, four digits, can be divided into: 3 1/2 digits, 3 3/4 digits, and 3 5/6 digits. Taking 3 1/2 digits as an example, the maximum number of displayed words is 1999, and the resolution is 1/2000 of the range.

Four and a half, that is, five digits, can be divided into: 4 1/2 digits, 4 3/4 digits, and 4 5/6 digits. Taking 4 1/2 digits as an example, the maximum display word count is 19999, and the resolution is 1/20,000 of the range.

Accuracy
Accuracy is the maximum error between measured and true values ***203;***203;under certain conditions. In other words, the accuracy indicates how close the multimeter's measured value is to the actual value of the measured signal.

The reading accuracy is expressed as "% of measured readings". For example, the voltage measurement accuracy is ±1% of the reading, which means: for a voltage measurement display of 100.0V, the true value of the voltage is between 99.0V and 101.0V.

In the technical specifications of digital measuring instruments, in addition to the reading accuracy index, a numerical error range is generally added, which indicates the maximum error range that may exist on the last bit of the measured display reading.

For example, the accuracy is expressed as: ± (1% + 2). If a three-and-a-half-digit digital multimeter is used to test 100V, the actual display value will be between 98.8 and 101.2V.