Hello. What is the meaning of insulation class for printed circuit board like Class 4 as in the attachment that I enclose? What is insulation classification for printed circuit board?
I'm also not sure what they are referring to. My best guess is the FR (Flame Retardent) rating of the laminate (could be referred to as the insulation I guess?), FR-1, FR-2, FR-3 and FR-4. Almost all boards now are FR-4.