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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:. u* O6 [- c7 k5 u! P s* {
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
5 ~6 @! X4 [% O( j0 ^can be evaluated with different environmental pollution degrees. The following conditions apply:
* H- Q, V; W* i# _3 T. m1 `a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.+ U4 x8 |# q8 P9 q' i! ^1 Y; p2 g8 T
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.+ Q4 X D# o/ Y5 D0 m0 E9 U# y
c) The portion of a printed wiring board covered with a potting compound or a conformal3 D2 I; s+ ^5 _1 r0 v
coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be& A/ o: t1 G+ w6 ]
exposed to environmental pollution degree 1. |
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