How to use a multimeter to judge the quality of a 15000μF large capacitor
The quality of a 15000 μ F large capacitor can be judged by charging and discharging it using a multimeter resistance range. This method is not very feasible because the test current of a multimeter resistance range is generally very small (μ A level), and measuring such a large capacitor takes a long time for charging and discharging. A simple way to judge the quality of a 15000 μ F capacitor is to use the diode or capacitor settings of a digital multimeter. Below are two methods introduced separately.
1. Measure the capacity directly using the capacitance range of a digital multimeter
Measure the capacitance directly with a digital multimeter in the capacitance range.
Many digital multimeters nowadays can measure capacitors below 20mF (where "mF" is pronounced as "millimeter", 1mF=1000 μ F) (previous multimeters could only measure capacitors up to 200 μ F), so to judge the quality of a 15000 μ F capacitor, the capacitance range of the multimeter can be directly used to measure its capacity.
The 4700 μ F electrolytic capacitor measured by a multimeter.
Use a DT9975 digital multimeter to measure the capacity of a 4700 μ F capacitor (due to the lack of a 15000 μ F capacitor). The reading shown in the figure is 4.502mF, which is 4502 μ F. Due to the large error of electrolytic capacitors, the displayed capacity is normal. When measuring a large capacity electrolytic capacitor, if the displayed reading remains at "1" without exceeding the range, it indicates that the capacitor has a large leakage or has been damaged due to breakdown. If the measured capacitance is much smaller than the nominal value, it indicates that the electrolyte inside the capacitor has dried up and is generally not suitable for use.
2. Use a digital multimeter diode range to judge the quality
If there is no digital multimeter that can measure large capacity capacitors, the diode range of a regular digital multimeter can also be used to simply judge the quality of the capacitor. Due to the high testing current of the diode mode (mostly over 1mA), measuring whether the large capacitor is broken down or damaged can be quickly measured through the diode mode. When measuring, use a multimeter probe to touch the two pins of the capacitor. If it is a good capacitor, the reading displayed in the diode mode may be "0.000" for the first ten seconds, and then the displayed reading will gradually increase until it shows "1". If the multimeter displays a reading of 0.000 for a long time (or a consistently low reading) during measurement, it indicates that the capacitor is damaged.
