| 摘要 |
Apparatus for sensing the arrival of a coin in coin handling mechanisms and producing an output signal only if the coin is of an acceptable type of material. The coin is placed between transmitting and receiving coils. The transmitting coil produces an oscillating magnetic field with components of different frequencies. The amplitudes of the components of the two different frequencies are examined and if they correspond to the amplitudes for an acceptable type of material, e.g. conductive non-ferromagnetic, the apparatus indicates the arrival of a coin. |
