How to judge the quality of DC current level (DCA)?
If there is a known current source, input it directly in the current range. If not, it doesn't matter. Just input the voltage in the current range. If it is 1, shift it to a lower range range until a valid value appears. Please also pay attention to the following points:
A, Please do not input too high voltage to avoid damaging the instrument due to excessive current. Commonly used sources for input include regular batteries, such as No. 5, No. 7, etc;
B, When measuring the current of the input voltage, due to the small resistance (load) of the internal resistance of the instrument, if the input is too long, it will damage the source. Therefore, it is recommended not to exceed 5 seconds for a single input;
C, The relationship between each high and low range, adjacent ranges, is generally 10 times.
How to judge the quality of capacitance level (CAP)?
Generally, it is to find a capacitor with a known value and directly insert it for measurement. The displayed values of each range should be in a 10 fold ratio relationship; When testing, use good metal capacitors with stable capacity and high accuracy. It is not recommended to use electrolytic capacitors for testing as they have poor stability and accuracy.
What is the basic working principle of a digital multimeter The basic circuit of a digital multimeter is a meter head circuit, which performs the basic function of quantifying the input DC voltage (analog quantity) and outputting it; Other functions generally require the addition of external circuits. PS: Nowadays, the integration of multimeter chips is increasing, and the number of peripheral circuits is decreasing. This has both advantages and disadvantages. Advantages: High integration, simple external circuits, and fewer quality faults caused by component quality issues; Disadvantages: Once the chip is broken, the replacement cost is high and troublesome. Sometimes, even the cost of replacing a chip can be used to buy another instrument, so generally, it is only easy to report if it is broken
