?? ???? ????????? ???????? ?? ?????? ?????? ????? ????? ?? ?????? ?????? ????? ?????.??? ?? ????? ?? ????? ? ????? ????????? ???????? ????? ?? ????? ???? ????? ??? ??????? ??????? ??? ?????? ????? ???? ????? ??? ????? ?????? ??? ?????? ??? ??? ???.As a consequence of eddy currents induced while in the steel, a sign is detected when steel is current