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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:
& c9 \/ C% j6 |& Q) S9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device4 e9 p% Y8 ?* ^6 ?
can be evaluated with different environmental pollution degrees. The following conditions apply:% y- z; ^$ K0 y; c
a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.$ H [3 ~) ~+ a: O( J! f$ S
b) A device intended for dry locations shall be exposed to environmental pollution degree 2.+ N/ l7 N- V( x* G+ R6 a( G& |+ E
c) The portion of a printed wiring board covered with a potting compound or a conformal
- N9 X/ v, l& m6 P4 icoating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be3 {' Z7 R+ M4 N/ [/ a2 f n) `
exposed to environmental pollution degree 1. |
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