Capacitors play an important role in electronic components. Whether they are safety capacitors, ceramic capacitors, monolithic capacitors, film capacitors or varistors, they may face the risk of breakdown. Capacitor breakdown is a phenomenon caused by the electric field strength experienced by the dielectric exceeding its limit. This usually occurs when charges break away from atoms or molecules to conduct electricity, destroying their insulating properties.
So, what exactly causes the dielectric insulation of the capacitor to be destroyed? There are several main reasons: first, one of the most common reasons is that the working voltage exceeds the withstand voltage value of the capacitor; second, poor quality of the capacitor, such as large leakage current, will cause the temperature to gradually increase, thereby reducing the insulation strength; finally , reverse polarity capacitor connection or incorrect connection to the AC power supply will also cause breakdown.
Once a capacitor breaks down, its ability to recover depends on the type of dielectric. If the dielectric is a gas or liquid, the breakdown is usually reversible, that is, they are self-restoring insulating media. But for solid dielectrics, breakdown is irreversible, meaning that once breakdown occurs, the capacitor cannot return to its original state.
So, how to avoid dielectric breakdown of capacitors? First of all, choosing materials with high insulation strength is key. Second, make sure the insulation is the proper thickness and free of impurities like air bubbles or moisture. In addition, reasonable design of electric field distribution to avoid excessive density of power lines in certain areas is also an important preventive measure. When selecting components such as safety capacitors, ceramic capacitors, monolithic capacitors, film capacitors, and varistors, choosing original manufacturers with quality assurance is also an important step in preventing capacitor breakdown.
In short, the main reason for capacitor breakdown is that the insulation of the dielectric is destroyed and polarization occurs. This may be caused by the working voltage exceeding the withstand voltage, capacitor quality problems, or wrong polarity connection. Understanding these causes and taking appropriate preventive measures are crucial to ensuring the proper operation of the capacitor and extending its service life.