A method for protecting a portable wireless device comprises providing a heat-shrinkable, light transmitting plastic bag; inserting the wireless device within the bag; heat shrinking the bag to intimately contact the outer surfaces of the wireless device with the interior surface of the bag. When a request to acquire this personal information is subsequently issued, the data portions that are registered with areas under different control are combined to restore the personal information. A density of the electrode windows is sufficient to monitor a distance of the flexible strip from a non-conductive tissue of a patient in a 360 degree field of view about the longitudinal axis. During a turn-on portion of the transition phase, the blocking voltages are reduced using another saturable reactor in series with a free-wheeling diode.