What is the difference between three and a half digits and four and a half digits on a digital multimeter?
Three and a half digits are also called 3 1/2 digits (pronounced as three and one-half digits), and four and a half digits are also called 4 1/2 (pronounced as four and one-half digits). We know that after an analog quantity is quantized and converted into a number, the accuracy it represents is related to the number of digits in the number. The more digits in the number, the closer it is to the original value and the more accurate it is (this is generally speaking , regardless of other circumstances, if the quantized value is 1.00000V, using one bit to express it is the same as using N bits to express it (:). So in general, the more digits, the more accurate it is, that is, four digits Half is more accurate than three and a half.
What is the basic working principle of a digital multimeter?
The basic circuit of a digital multimeter is a meter circuit. The basic function it performs is to quantify the input DC voltage (analog quantity) and output it; other functions generally require the addition of external circuits. PS: Nowadays, multimeter chips are becoming more and more integrated and have fewer and fewer peripheral circuits. This has both advantages and disadvantages. Advantages: High integration, simple external circuits, and fewer quality failures caused by component quality problems; Disadvantages: Once the chip breaks, replacement costs are high and troublesome. Sometimes the money spent to replace a chip can be used to buy another instrument, so Usually it has to be scrapped if it breaks down.
How to judge the quality of DC current profile (DCA)?
If there is a known current source, input it directly in the current gear. If not, it doesn't matter. Just input the voltage in the current gear. If it comes out as 1, move to the low range gear until a valid value appears. , please also note the following points:
A. Please do not input too high voltage to avoid excessive current and damaging the instrument. Commonly used sources that can be input include ordinary batteries, such as AA, AA, etc.;
B. When inputting voltage and measuring its current, since the resistance (load) of the internal resistance of the instrument is very small, if the input is too long, the source will be damaged, so a single input should not exceed 5 seconds;
C. The relationship between each high and low range and adjacent ranges is generally 10 times.
