How to Assess Whether the DC Current Range (DCA) Works Properly?
If there is a known current source, input it directly in the current mode. If not, it doesn't matter. Just input the voltage in the current mode. If it outputs 1, shift it to the lower range mode 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. Common sources that can be 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, a single input should not exceed 5 seconds as much as possible;
C, The relationship between different high and low ranges, adjacent ranges, is generally 10 times.
How to determine the quality of the capacitor level (CAP)?
Answer: 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; It is best to use metal capacitors with stable capacity and high accuracy during testing. It is not recommended to use electrolytic capacitors for testing, as their stability and accuracy are poor.
What is the basic working principle of a digital multimeter?
Answer: The basic circuit of a digital multimeter is a header circuit, which quantifies the input DC voltage (analog) and outputs it; Other functions generally require the addition of external circuits. PS: Nowadays, the integration level of multimeter chips is increasing, and the peripheral circuits are becoming fewer and fewer, which has both advantages and disadvantages. Advantages: High integration, simple external circuits, and fewer quality failures caused by component quality issues; Disadvantage: Once the chip breaks down, the replacement cost is high and troublesome. Sometimes, the money spent on replacing one chip can be used to buy another instrument, so usually it has to be scrapped.
