safety film capacitor belongs to a special branch of film capacitors, which is developed for power input anti-interference and safety protection. Ordinary film capacitors include CL21 polyester film capacitors and conventional CBB polypropylene capacitors, which are mainly used for signal coupling, timing and DC filtering without mandatory safety requirements.

safety capacitor failure mode standard: Safety capacitors are required to fail open circuit after overvoltage breakdown to avoid short-circuit fire hazards. Ordinary film capacitors have no such design requirement, and short-circuit failure is likely to occur under severe surge, which cannot be used for live wire and neutral wire filtering of mains power.

safety capacitor certification requirement: X and Y safety capacitors must obtain UL, CQC, VDE and other safety certifications, and the certification marks must be printed on the capacitor body. Ordinary film capacitors do not need safety certification, only basic electrical performance test is required before delivery.

weidy CBB capacitor suggests that the two types of capacitors cannot be confused in BOM. Safety capacitors are used for mains EMI filtering, while ordinary film capacitors are suitable for non-safety-critical low-frequency and DC circuits.