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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: G) o" u& |& ]3 C [$ x D# J, {9 P
9.8 When applying the requirements specified in UL 840 to determine environmental pollution, the device
3 L+ Z5 V# R I6 I& Vcan be evaluated with different environmental pollution degrees. The following conditions apply:
5 X( V$ y$ Y1 ^( }a) A device marked for damp or wet use shall be exposed to environmental pollution degree 3.
! E4 X7 s2 T- v1 d: ^b) A device intended for dry locations shall be exposed to environmental pollution degree 2.
# Q4 n3 g- E' D4 k% e2 Y4 wc) The portion of a printed wiring board covered with a potting compound or a conformal
* s. B2 H; B/ n8 O8 e6 b( zcoating that complies with the requirements in Conformal-Coating Tests, Section 32, shall be2 Z! R5 W: k A* r5 k# `
exposed to environmental pollution degree 1. |
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