Steel Ribbon Interrupter.
For light currents and rapid vibrations, such as are employed in electrotherapy, the steel ribbon interrupter is suitable. It consists of a steel ribbon V one-half inch wide by six or eight inches long and the thickness of a stout visiting-card. Near the end is riveted a platinum contact. One end of the ribbon is held by a brass upright R, to which connection is made to circuit; the other end is riveted to a threaded rod, which passes through a brass pillar, and is held by a thumb-screw and check nut S. Turning the thumb-screw either way tightens or loosens the ribbon and so raises or lowers the rate of vibration (Fig. 24).