Surface breakdown of printed circuit board under dc magnetic field

Surface dielectric breakdown phenomenon of printed circuit board (PCB) under dc magnetic field was investigated, we employed a dc magnetic field, which was made at 395 mT, and the electrical field was made at 60 kV/mm, 100 kV/mm and then up to 300 kV/mm. The experiment was carried out by dc pulse voltage with the frequencies in the range of 50 Hz to 150 Hz. PCB of epoxy resin laminate have been employed to investigate the effects of the magnetic field, the density of electrical field and the frequencies of applied voltage on discharge quantity. The relation between the time to insulation breakdown and the electrical fields under dc magnetic field were examined. Surface dielectric breakdown is caused by decomposed carbon on the sample surface, which is precipitated due to heat from discharge currents occurred between the electrodes. The study revealed that the time to breakdown decreases under magnetic field and decreases with increasing the density of electrical field. The characteristics of discharge currents were discussed by using a power spectral density. The results show that the power spectral density of discharge currents increases under magnetic field and with increasing the density of electrical fields.