The site where the electrodes touch the skin serves as a point of conversion between the flow of electrons used by the electrotherapy device and the flow of ions within the body’s tissues. To form a closed circuit between the device and the patient’s tissues, at least one electrode from each of the device’s output leads must be in contact with the patient’s skin. Properly prepared and placed electrodes increase the efficiency of the electrical current while allowing for less discomfort from the treatment.