Partial discharge. VI: PD testing of printed circuit boards

For pt.V see ibid., vol.7, no.2, p.28 et seq. (1991). The results of a research program concerned with applying partial-discharge (PD) testing to the nondestructive evaluation of the dielectric characteristics of coated printed circuit board (PCB) systems that must meet the high-voltage dielectric test requirements of low-voltage equipment are reported. To insure that the resulting data were applicable to typical PCBs a standardized test board layout was used, and the various coatings applied to the board were subjected to a range of conditioning treatments. The measurement and test specimens are described. The PD inception voltage and extinction voltage data for seven coatings and four conditioning regimes are presented, for either parallel conductor traces or pads adjacent to conductor traces, as measured from either the component or the solder side of the board. The data indicate that PD measurements, in combination with suitable conditioning, provide a good tool for determining the quality of coated PCBs. If applied correctly, the PD test is nondestructive.<>