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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:
" [9 B& s. b) [$ f1 k4 s9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device4 s3 g5 [, ~0 Y+ o
can be evaluated with different environmental pollution degrees. The following conditions apply:
; R, \& r' \" N5 d/ e9 O& m! @/ Ja) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.
" ~0 R* m% n# `' pb) A device intended for dry locations shall be exposed to environmental pollution degree 2.
/ I8 R3 P5 a/ l6 S) hc) The portion of a printed wiring board covered with a potting compound or a conformal
/ X1 c0 {6 S+ mcoating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be6 Z! O( s' ^8 d; k
exposed to environmental pollution degree 1. |
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