This work investigates the influence on the partial discharge (PD) onset due to the geometry of solder fillets of aerospace and spacecraft component assemblies operating in vacuum and at high voltages. An automatic measuring system has been developed and calibrated to detect PD signals in vacuum (proportional to the apparent charge) which are recorded and displayed in terms of amplitude and temporal distributions. The experimental part of the project is aimed at investigating the influence of the geometry of solder fillets (produced according to the European space industry standard, ECSS-Q-70-08), on the occurrence of PD activity. Stranded terminals of high voltage cables were soldered to circular copper pads on FR4 fiberglass epoxy printed circuit board (PCB). Various copper electrode configurations have been produced and, prior to the test program, they were characterized for dimensional, electrical and optical properties. Two types of solder fillet geometries have been realized for each electrode configuration: round joints with an abundance of solder and sharp pointed joints made with minimal solder. The minimum distance between electrodes for all samples is nominally 5 mm. Paschen-like curves were established from measurements performed where the product of pressure x distance lies in the range of 2 mbar mm-50 mbar mm. Corona inception voltage (CIV) and corona extinction voltage (CEV) values were recorded at different values of pressure x distance. Stable glow discharge triggering voltage and current were also measured. The experimental results indicated that the PD activity for the sharp pointed pads and sharp pointed joints is greater than the other cases, but no significant differences (less than 50 V) of the values of CIV and CEV have been found.Index Terms-High voltage systems, partial discharges, printed circuit board, solder fillets.

This work investigates the influence on the partial discharge (PD) onset due to the geometry of solder fillets of aerospace and spacecraft component assemblies operating in vacuum and at high voltages. An automatic measuring system has been developed and calibrated to detect PD signals in vacuum (proportional to the apparent charge) which are recorded and displayed in terms of amplitude and temporal distributions. The experimental part of the project is aimed at investigating the influence of the geometry of solder fillets (produced according to the European space industry standard, ECSS-Q-70-08), on the occurrence of PD activity. Stranded terminals of high voltage cables were soldered to circular copper pads on FR4 fiberglass epoxy printed circuit board (PCB). Various copper electrode configurations have been produced and, prior to the test program, they were characterized for dimensional, electrical and optical properties. Two types of solder fillet geometries have been realized for each electrode configuration: round joints with an abundance of solder and sharp pointed joints made with minimal solder. The minimum distance between electrodes for all samples is nominally 5 mm. Paschen-like curves were established from measurements performed where the product of pressure x distance lies in the range of 2 mbar mm-50 mbar mm. Corona inception voltage (CIV) and corona extinction voltage (CEV) values were recorded at different values of pressure x distance. Stable glow discharge triggering voltage and current were also measured. The experimental results indicated that the PD activity for the sharp pointed pads and sharp pointed joints is greater than the other cases, but no significant differences (less than 50 V) of the values of CIV and CEV have been found.Abstract-This paper discusses the transition to lead-free electronics, with emphasis on Japanese companies. The results of reverse engineering two Japanese minidisk players with "green" labels are presented. The minidisk players analyzed were Sony's MZ-E909 and Matsushita's SJ-MJ-90-A. Both of the minidisk players had three circuit cards, which were analyzed using a variety of methods including EDS, WDS, and ICP-AES. Data resulting from these tests was included along with a discussion on its significance. Moreover, the two "green" minidisk players were compared in terms of solder compositions and lead-free implementation strategies. This study revealed that products bearing the "green" label were not necessarily lead-free, but rather conformed to one of many definitions of lead-free devices. It was also found that the Japanese approach for achieving lead-free products appears to be based on an incremental transition by application, even at the board level.