Electronic devices are disclosed that allow for surface-mounting using solder while preventing solder from overflowing between external terminals of the electronic device, or between pads on a circuit board to which the external terminals are soldered. An exemplary electronic device has a base board made of an insulating material and having an outer surface comprising at least one external terminal for surface mounting of the device to the circuit board. A groove is defined at least part way around the external terminal on the outer surface. The groove accommodates overflowed solder and thus prevents unintended spread flow of the solder to locations that otherwise could cause short circuits and the like. The electronic device can include a resin board containing a thermoset resin, wherein the groove is formed by thermal or mechanical processing.