Judging capacitor quality with a multimeter

Depending on the size of the electrolytic capacitor, the multimeter's R×10, R×100, and R×1K gears are usually used for test and judgment. The red and black pens are connected to the negative electrode of the capacitor (before each test, the capacitor needs to be discharged), and the quality of the capacitor is judged by the yaw of the hands. If the hands quickly swing to the right and then slowly retreat to the left, the capacitor is generally good. If the hands are no longer swiveled after they have been swung, the capacitors have broken down. If the hands gradually swing back to a certain position and stop, the capacitor has already leaked. If the hands do not swing, the capacitor electrolyte has dried and lost its capacity.

Some leaky capacitors are not easy to judge accurately with the above method. When the voltage value of the capacitor is greater than the voltage value of the battery in the multimeter, according to the characteristics of the leakage current when the electrolytic capacitor is charged in the forward direction, and the leakage current during reverse charging is large, the R×10K block can be used to reverse charge the capacitor. Whether the stylus stays stable (ie, whether the reverse leakage current is constant), the quality of the capacitor is judged and the accuracy is high. The black pen is connected to the negative pole of the capacitor, the red pen is connected to the positive pole of the capacitor, and the hands quickly swing up and then gradually retreat to a point where they can't move, indicating that the capacitor is good. All the hands in a certain position stay unstable or stay and gradually The capacitor that has moved slowly to the right has been leaked and cannot be used anymore. The hands generally stay and stabilize within the range of 50-200K.