An electronic component including an operation body is mounted on a circuit board. The modulated carrier is preferably undersampled at two times the carrier frequency, thereby maximizing the sensors demodulated bandwidth relative to the sensors sampling frequency. The magnetic flux transmitted to the soft magnetic underlayer flows in the soft magnetic underlayer away from an area of the soft magnetic underlayer beneath the read element. The rifle may include a trigger block the prevents trigger operation until a neutral condition is detected. The training and information-bearing symbols are transmitted with equal power, respectively. With this arrangement, lead contained in the circuit boards can be sorted and separated without being diffused, and further, the volume of fragments of the circuit boards adapted to be mingled into fragments of other waste such as nonferrous metals and plastics can be decreased.