Named after Italian physiologist Luigi Galvani (17371798), Bell Telephone Laboratories developed the first high voltage Galvanic Stimulator in 1945. Unlike low voltage alternating current (AC) that is found in TENS, EMS/NMES and IF, Galvanic Stimulation is a source of high voltage direct current (DC). Unique in its application, a large dispersive pad is placed in a neutral area on the body to ground the current while the smaller "active" pads are placed over treatment area.