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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 f0 l7 } Y- M7 A3 ^% F9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
5 ^. o/ V9 H5 e1 b6 ucan be evaluated with different environmental pollution degrees. The following conditions apply:
" k: a' i& U1 m- N( Za) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.2 X/ R0 g0 G0 Y% F% w) I, f; }
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.
9 g$ u% z4 ?3 T% tc) The portion of a printed wiring board covered with a potting compound or a conformal7 k, J5 @& z/ a% F( @& t1 Y
coating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be: F% i4 k0 A$ A% L
exposed to environmental pollution degree 1. |
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