How to judge the quality of capacitors

Capacitors are components that can store charges and are also one of the most commonly used electronic components. There are many types of capacitors, including film capacitors, CBB capacitors, safety capacitors, etc., which are widely used in various fields. Normally, to judge the quality of the capacitor, the R×10, R×100, and R×1K gears of the multimeter will be used for testing and judgment. The red and black test leads are respectively connected to the negative pole of the capacitor (the capacitor needs to be discharged before each test), and the quality of the capacitor is judged by the deflection of the needle. If the hands of the watch swing to the right quickly and then slowly return to the original position to the left, a capacitor is generally good. If the hands do not rotate after swinging, the capacitor has broken down. If the watch hands gradually return to a certain position after swinging up, it means that the capacitor has leaked. If the hands of the watch cannot move, it means that the capacitor electrolyte has dried up and lost capacity.

For some leakage capacitors, it is not easy to accurately judge whether it is good or bad with the above method, and it will affect the actual public application of film capacitors, CBB capacitors, and safety capacitors. Therefore, the correct method of judging the leakage capacitor is very and always necessary.

When the withstand voltage value of the capacitor is greater than the voltage value of the battery in the multimeter, according to the characteristics of the electrolytic capacitor that the leakage current is small during forward charging and the leakage current is large during reverse charging, the R×10K gear can be used to reverse charge the capacitor. Observe Whether the watch hand stays stable (that is, whether the reverse leakage current is constant), the quality of the capacitor can be judged, and the accuracy is high. The black test lead is connected to the negative pole of the capacitor, and the red test lead is connected to the positive pole of the capacitor. The hands move up quickly and then gradually retract to a certain place to stop moving, indicating that the capacitor is good. If the needle stays unstable at a certain position or stops gradually, The capacitor moving slowly to the right has leaked and cannot be used anymore. The hands of the watch generally stay and stabilize within the 50-200K scale range.