| 摘要 |
<p>A method and an apparatus for testing and identifying electrically conductive discs, such as coins or equivalent. According to the method the effect of each coin on a magnetic field generated by means of coils is measured, the measurement result obtained in this way is compared with the reference value, and the coin is accepted if the measured value is close enough to the reference value. The reference value is determined on the basis of the effect produced by a preselected reference coin upon a magnetic field preferably of the same magnitude as the magnetic field to be measured. The magnitude of the magnetic field is measured in two directions at least substantially perpendicular to each other and the effect of the coin upon the symmetry of the magnetic field to be measured is taken into account by means of an additional coil placed at least substantially in the symmetry plane of the magnetic field to be measured.</p> |
