Temporary SMT Jumpers

Here's two ideas fro the fine SMTnet Archives: * On the bare board, during design / layout, the basic shape of the jumper is a 125 thou disc of copper [that of course is eventually covered with whatever solderability preservative we use on the board]. The disk is usually divided into two half discs, but sometimes we see quarter discs. Designers divide the disc in: ** Half with a 20-25 thou etch of the copper through the center of the disc. ** Quarters with two perpendicular 20-25 thou etches of the copper through the center of the disc. In assembly, we drag solder across the two half [quarter] disc to make a connection or wick the solder to break a connection.

* rather than applying jumpers, try thinking it another way. Have all possible jumper connections pre-made by the fab design. Use an exacto or dremel to "open" the undesired paths by removing a bit of copper trace. total flexibility, only one fab makes multiple assemblies. No need to worry about open or insufficient solder joints that don't operate electrically. [M Parker SMTnet]

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