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environmental pollution degree 是在UL840里对PCB板上电气间距要求的一个分级,LED 灯泡可以参考UL1993中的这段条款:: ^; ~4 H' x1 I9 W3 @$ Y! ? y7 B0 C
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device4 t1 S% r, f* H' b- Z' s6 f
can be evaluated with different environmental pollution degrees. The following conditions apply:
, D) \% b# p9 W! Aa) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.
; g5 K- R, N8 |6 a' p$ Gb) A device intended for dry locations shall be exposed to environmental pollution degree 2.4 G4 m0 P4 b: t
c) The portion of a printed wiring board covered with a potting compound or a conformal
, Q! s7 W% ]7 ?7 i/ Q* o3 \coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be
& D& b+ R, l) c) Q- t7 D/ H& D Dexposed to environmental pollution degree 1. |
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