In order to perform safe and effective electric stimulation in acupuncture analgesia or therapy, basic knowledge concerning the electric stimulator is required. If direct current is used, a negative square wave with a pulse duration of 0.5~1.5 msec should be applied to the needle electrode to perform elective stimulation. Negative current is more effective at lower amperage than positive current and the possible corrosion hazard by the positive current can be avoided
