Actual measurement data for estimating capacitance using a digital multimeter
Estimate 0.1 using DT830 digital multimeter μ When measuring the capacitance of capacitors ranging from F to several thousand microfaragons, the resistance range can be selected according to Table 5-1, which provides the range of measurable capacitance and corresponding charging time. The data listed in the table also has reference value for other models of digital multimeters.
The principle of selecting a resistance range is that when the capacitance is small, a high resistance range should be selected, while when the capacitance is large, a low resistance range should be selected. If high resistance range is used to estimate large capacity capacitors, the measurement time will last for a long time due to the slow charging process; If using a low resistance range to check a small capacity capacitor, due to the extremely short charging time, the instrument will continue to display overflow and the change process will not be visible.
How to judge the quality of air conditioning capacitors
Use a digital multimeter to check. Set the digital multimeter to the appropriate resistance range, with the red and black probes touching the two poles of the tested capacitor. At this point, the displayed value will gradually increase from 000 until the overflow symbol "1" is displayed. If the display always shows 000, it indicates an internal short circuit in the capacitor. If overflow is always displayed, it may be due to an open circuit between the internal poles of the capacitor, or it may be due to an inappropriate resistance range selected.
In order to see the charging process of capacitors on the display screen, different resistance levels should be selected for capacitors of different capacities. The principle of selecting a resistance range is: when the capacitor is large, a low resistance range should be selected; When the capacity of the capacitor is small, a high resistance range should be selected. If a low resistance level is used to check a small capacity capacitor, due to the short charging time, overflow will continue to be displayed and the change process cannot be seen, making it easy to misjudge that the capacitor is open circuit. If using a high resistance range to check large capacity capacitors, due to the slow charging process, the measurement time needs to be longer and longer. For capacitors above 0.1~1000uF, the resistance range can be selected according to the following table (the charging time in the table refers to the time required for the display range to change from 000 to overflow).
