How to Check if a Capacitor is Good or Bad Using a Multimeter
If a general capacitor is broken, it can be distinguished from its appearance, and the most obvious feature is that it will crack and show obvious signs of damage. For example, the picture below is a real-life shot of a capacitor explosion, which is easy to identify. There are also many capacitors in the circuit that are damaged due to explosion, so this method is still very useful.
Use the capacitance range of a multimeter to distinguish
For capacitors with smaller capacities, they can be directly identified using the capacitance range of a multimeter. Measuring capacitance with a multimeter is relatively simple, even if the capacitance is distinguished between positive and negative poles. When measuring with a multimeter, the capacitance size is usually marked on the outside of the capacitor. Therefore, the capacitance size measured by the multimeter can be compared with the marked size. If there is a large difference between the two, or if the data cannot be measured at all, it can be concluded that the measured capacitor is broken. On the contrary, if the capacitance is relatively close, then this capacitor is good.
Use diode mode to distinguish
The previous method is reliable, but when the capacity is large, the capacitance has already exceeded the range of the multimeter, and this method is not feasible. It doesn't matter, we still have a solution, which is to use the diode mode to measure. The measurement method is similar to the method of measuring capacitance, but slightly different. When using the capacitance mode to measure, there is no need to distinguish the positive and negative poles of the capacitor, but this is distinguished. Place the black probe on the positive pole of the capacitor (when using the internal power supply, the current flows out from the black probe), and place the red probe on the negative pole of the capacitor. If you see that the number on the multimeter dial is constantly increasing, and the larger the capacity, the more obvious this phenomenon becomes, then you can conclude that this capacitor is... Okay.
Use a resistance barrier to distinguish
In addition to the three methods mentioned above, the resistance range can also be used for measurement. I can't believe it. This method is very similar to measuring with a diode range. It also distinguishes the positive and negative poles, connects the black probe to the positive pole of the capacitor and the red probe to the negative pole of the capacitor, and selects the appropriate resistance range. In the test, I chose the 20K range. This phenomenon is very obvious during measurement, and it can be clearly seen on the multimeter display screen that this number is increasing. If the capacity of the capacitor is larger, this phenomenon will become more obvious and the growth rate will be slower.
