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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:6 M/ M! |, V9 o, x y% E! z
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
5 _. t6 {* Z; t" }6 D2 t2 _$ u) rcan be evaluated with different environmental pollution degrees. The following conditions apply:
+ E' b8 P2 B: H6 H% K I6 ^a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.% V6 D8 b; B6 o9 @
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.. u- T% L, C( w3 Y& Q+ y1 P
c) The portion of a printed wiring board covered with a potting compound or a conformal
8 E) C9 `0 `, e7 j: S% S8 vcoating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be
. _5 w+ A, Y% g% L2 z# ?. Z: xexposed to environmental pollution degree 1. |
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