How do we test high-ripple-resistant electrolytic capacitors for leakage? And how should we handle any detected faults?
Release time:
2022-11-14
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High-ripple-resistant electrolytic capacitors use an aluminum cylinder as the negative electrode, contain a liquid electrolyte inside, and have a bent aluminum strip inserted as the positive electrode. They also require DC voltage treatment to form an oxide film on the anode plate, which serves as the dielectric. These capacitors are characterized by large capacitance, high leakage current, poor stability, and polarity sensitivity; they are suitable for power filters or low-frequency circuits. When using them, be sure not to connect the positive and negative terminals incorrectly.
High-ripple-resistant electrolytic capacitor It uses an aluminum cylinder as the negative electrode, contains a liquid electrolyte inside, and has a bent aluminum strip inserted as the positive electrode. It also requires DC voltage treatment to form an oxide film on the anode plate serving as the dielectric. Its characteristics include high capacitance, significant leakage, poor stability, and polarity sensitivity—making it suitable for power filters or low-frequency circuits. When using, do not connect the positive and negative terminals incorrectly.
When using a multimeter to measure the leakage current of a high-ripple-resistant electrolytic capacitor, connect the multimeter’s red test lead to the negative terminal of the electrolytic capacitor and the black test lead to the positive terminal. At the moment of contact, the multimeter’s needle will deflect significantly to the right (for capacitors of the same type, the larger the capacitance, the greater the deflection). Then, the needle will gradually swing back to the left until it comes to rest at a certain position. The resistance value displayed at this point is the forward leakage resistance of the electrolytic capacitor. The higher this value, the smaller the leakage current, and the better the capacitor’s performance.
Practical experience shows that the leakage resistance of high-ripple-resistant electrolytic capacitors should be above several hundred ohms; otherwise, they cannot function properly. During testing, if there is no charging phenomenon in either direction—that is, the pointer remains stationary—this indicates that the capacitor has failed or its internal circuit is open. If the resistance value is very low or zero, it means the capacitor is leaking current or has suffered dielectric breakdown and should not be used.
When performing the test, be sure to select an appropriate measurement range. If the capacitor's rated voltage exceeds the voltage of the internal battery in the multimeter, you can use the Rx10k range to charge the electrolytic capacitor in reverse. Given that the leakage current is low when the capacitor is charged in the forward direction and high when charged in the reverse direction, observe whether the pointer's stopping position remains stable (i.e., whether the reverse leakage current is constant). This allows for a highly accurate assessment of the capacitor's condition.
So then High-ripple-resistant electrolytic capacitor What should you do if a malfunction occurs? Here are a few points:
1. For the neutral wire of a patch-type electrolytic capacitor bank connected in a double-star configuration, as well as for multiple patch-type electrolytic capacitors connected in series, each should be discharged separately. Chip-type high-ripple-resistant electrolytic capacitors are electrical components with relatively low reliability used in various devices such as power converters, filters, and couplers. Compared with other devices operating at the same voltage, they have weaker insulating electronic components, generate more internal heat, exhibit poor heat dissipation, and are more prone to internal failures. The internal materials used in the manufacture of power chip-type electrolytic capacitors contain a high proportion of flammable substances, making them easily susceptible to ignition during operation.
2. After the surface-mount high-ripple-resistant electrolytic capacitor has been discharged via a discharge resistor (discharge transformer or discharge voltage transformer), even though some residual charge will have been dissipated over time, it is still necessary to perform manual discharge. During discharge, first connect the grounding terminal of the grounding wire, then use a grounding rod to discharge the surface-mount electrolytic capacitor several times until no discharge sparks or sounds are heard. Finally, securely fasten the grounding terminal.
3. Because it’s faulty High-ripple-resistant electrolytic capacitor It is highly likely that issues such as poor lead contact, internal open circuits, or blown fuses may occur. Some residual charge might not be fully discharged. Therefore, before handling faulty surface-mount electrolytic capacitors, all types of maintenance personnel should wear insulated gloves, first short-circuit the faulty surface-mount electrolytic capacitor and then proceed with its removal and replacement.
Keywords:
High-ripple-resistant electrolytic capacitor
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