safety film capacitor is widely used in the EMI filter of mains power supply. Its failure will directly cause the terminal product to fail EMC and safety certification, and even bring hidden dangers such as electric shock and fire. Common failure causes include overvoltage surge, excessive ripple current, moisture ingress, long-term high temperature aging and poor sealing process. The metallized layer will be corroded and peeled off under high humidity, resulting in capacitance drop and leakage current rise.

safety capacitor failure mode analysis: Overvoltage and surge will trigger repeated self-healing, gradually consume the metal coating and reduce capacitance. Continuous high ripple current will generate internal heat and accelerate dielectric aging. Poor encapsulation and sealing will let moisture penetrate into the core, which is the main cause of electrochemical corrosion of metallized film. Improper PCB layout and excessive mechanical stress during welding will also cause internal lead fracture.

safety capacitor quality control scheme: Reliable factories carry out IQC inspection of raw film and metallization material first. IPQC monitors winding, hot pressing, metal spraying and encapsulation in real time. Finished products need to pass capacitance, dissipation factor, withstand voltage, insulation resistance and humidity load test. Batch sampling shall be arranged for accelerated aging and surge test to verify the stability of failure mode.

weidy safety capacitor recommends that purchasers confirm the application stress of the circuit before selection. It is necessary to reserve sufficient voltage margin for X2 and Y capacitors. Avoid using them in high-temperature and high-humidity environment without protection. If abnormal capacitance drift or leakage current increase is found during mass production, stop delivery and carry out failure analysis in time.