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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 X7 T3 n0 g3 ~1 ` o& W
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device; [) C& U+ I3 y8 r7 I+ j+ V
can be evaluated with different environmental pollution degrees. The following conditions apply:4 i& x* q1 Q1 k. u F
a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3./ H, F) j# z; j
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.
. L% I% ?$ }- |8 y/ J( O, xc) The portion of a printed wiring board covered with a potting compound or a conformal/ D# \/ C: ^& z7 }7 G- J5 f
coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be
! L, e5 ?/ l$ g4 \, C: Texposed to environmental pollution degree 1. |
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