Some thin (0.8 or 1 mm) FR4 boards add a nice milky or yellowish tint which can look good when used for indicator LEDs, or even night lamps or some LED Art gadgets. The following examples combine ...

Inspection of its innards revealed that some unlucky ants had shorted across line and neutral on the power supply board, which burned not only the traces but the FR4 of the board as well.

For example, the tolerance in timing skew between parallel signals in a multi-drop environment is approaching the practical limit achievable in low-cost FR4 printed circuit boards. In addition, the ...