| 摘要 |
An operable toy utilizes a metal sensing apparatus which includes a tuned circuit which includes a pick-up coil. The resonance frequency of the resonance circuit shifts when the pick-up coil senses a metal or magnetic object. A motor is normally driven in the absence of the sensing of a metal or magnetic object. When the metal or magnetic object is sensed, the frequency shift of the tuned circuit including the pick-up coil attenuates the frequency produced by an oscillator and as the voltage of the signal produced by the oscillator is attenuated, a level detection circuit produces a low output to thereby disconnect the power from the motor. Alternatively, the power to the motor may be reversed. Two metal sensing apparatuses may be utilized in an operable toy to cause the toy to follow a track of metallic or magnetic material.
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