Method for judging electrolytic capacitor
Common faults of electrolytic capacitors include capacity reduction, capacity loss, breakdown short circuit and leakage. The change in capacity is caused by the internal drying of the electrolytic capacitor during use or placement, and the breakdown and leakage are generally added. The voltage is too high or caused by poor quality. Judging whether the power supply capacitor is good or bad is generally measured by the multimeter's resistance file. The specific method is as follows: short circuit the two pins of the capacitor to discharge, and connect the positive electrode of the electrolytic capacitor with the black meter of the multimeter. The red pen is connected to the negative pole (for the pointer type multimeter, when the digital multimeter is used to measure the intermodulation)
Normally, the hands should first swing in the direction of low resistance and then gradually return to infinity. The larger the swing amplitude of the hands or the slower the return speed, the larger the capacity of the capacitor, and the smaller the capacity of the capacitor. If the pointer does not change somewhere in the middle, it indicates that the capacitor is leaking. If the resistance indicator is small or zero, it indicates that the capacitor has broken through. Since the battery voltage used by the multimeter is generally low, it is more accurate when measuring the low withstand voltage capacitor, and when the withstand voltage of the capacitor is high, although the measurement is normal, when the high voltage is applied, there is a possibility of electric leakage or blow. Wear phenomenon.