Device for checking the validity of coins, tokens or other flat metallic objects

摘要

The device proposed includes a channel, with a lower and an upper wall, along which a coin moves, lying on the lower wall, past at least one inductive sensor with a coil (S). The coil (S) is fed with a first current (I>1<) from a first power or voltage source (19) and with a second current (I>2<) from a second power or voltage source (21). Between the coil (S) and the first power or voltage source (19) is a capacitative element (C>1<) connected in such a way that the coil (S) and capacitative element (C>1<) form an impedance (Z>1<). The phase difference ( phi >1<) between the first current (I>1<) and the voltage across the impedance (Z>1<) is used as the criterion for acceptance or rejection of the coin.