... which additionally require a complex waste water processing infrastructure. The immersion nickel gold process also requires staff intensive attention as the chemical baths call | PRINTED WIRING BOARDS | for a great deal of analysis and supervision due to the narrow processing slit. The process of solder mask coating as well as de- oxidation | PRINTED WIRING BOARDS | of bare copper surfaces (activation) must perfectly match the gold plating. To prevent the risk of poor metallic deposition on the gold surface, vias must be | PRINTED WIRING BOARDS | completely free of solder mask coating or be completely closed by means of a special filling process. Curing of the solder mask coating must also | PRINTED WIRING BOARDS | concur with that of the chemical gold plating as it is exposed to hydrogen in the 90° C nickel baths. One has the choice between | PRINTED WIRING BOARDS | an expensive coating system or a subsequent infrared solidification which, in turn, also calls for further investment in facilities. THE POTENTIAL For a lead free | PRINTED WIRING BOARDS | altenative provided the PCB manufacturer ensures optimal conditions for ...
[ Printed Wiring Boards ]


... with breakaway tabs. The panels make handling easier for automatic insertion and wave soldering. The boards can be separated by snapping apart. | BREAKDOWN | PRINTED WIRING BOARDS | VOLTAGE | The voltage at which an insulator or dielectric ruptures, or at which ionization and conduction take place in a gas or vapor. | | PRINTED WIRING BOARDS | BRIDGING ELECTRICAL | The formation of a conductive path between conductors. | B-STAGE | The condition of a resin polymer when it is more viscous, | PRINTED WIRING BOARDS | with higher molecular weight, and insoluble but plastic and fusible. Semi-cured. | B-STAGE MATERIAL | Sheet material impregnated with a resin cured to an intermediate | PRINTED WIRING BOARDS | stage. Prepreg is the preferred term. | B-STAGE RESIN | A resin in an intermediate state of cure. The cure is normally completed during the | PRINTED WIRING BOARDS | laminating cycle. | BURIED CAPACITANCE | A method and technology for adding de- coupling capacitance to the innerlayers of a multilayer, thereby saving space and | PRINTED WIRING BOARDS | increasing functionality. | BURIED VIA | Connects one inner layer to another inner ...
[ Printed Wiring Boards ]


... thorough PCB test. Optical checks with the aid of conventional micro-scopic equipment are sufficient for one sided and relatively simple double-sided PCBs. Residues, constricted | PRINTED WIRING BOARDS | conductors and subcorrosions can be discovered which would otherwise lead to PCB failure after a number of operational hours. An electrical test is needed to | PRINTED WIRING BOARDS | check the actual functions of a PCB. It is an essential if inner layers need to be tested, as is the case with multi-layers. In | PRINTED WIRING BOARDS | two position measure-ments all connections in the PCB are checked for stoppages and short circuits. All SMD pads and plated through holes are checked. The | PRINTED WIRING BOARDS | electrical test can be conducted as a parallel or finger test. Parallel test: For the parallel test a control adaptor is constructed, consisting, e.g. of | PRINTED WIRING BOARDS | several synthetic sheets positioned above each other and fitted with control pins. An adaptor programme must be written to reflect the actual holes in each | PRINTED WIRING BOARDS | individual synthetic layer of the adaptor. The pin positions are ...
[ Printed Wiring Boards ]