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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:
0 r( C" j4 H$ u0 b2 g9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
+ i" A/ q5 o7 G8 |, _can be evaluated with different environmental pollution degrees. The following conditions apply:
+ p% ^" A" j5 M+ Ea) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.$ X7 m5 i+ {* a! p( g3 B( b
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.% T! f" ^; i8 [( F' ?2 B+ k* Q) A! h
c) The portion of a printed wiring board covered with a potting compound or a conformal; P, F% b; @4 \/ y
coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be% i1 m+ B' G! \3 a& B. P
exposed to environmental pollution degree 1. |
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