| 摘要 |
PURPOSE:To improve the reverse current distortion produced in a stator coil by adding a negative feedback circuit to an amplifier for driving the coil. CONSTITUTION:A voltage in response to the position of a magnet is outputted to a Hall element 1, but the output of a comparator becomes the prescribed DC voltage V0 at the threshold level or higher. The V0 becomes alphaV0 by the amplifier 2 to drive a coil 3, thereby rotating a rotor, but when the rotor rotates, a counterelectromotive force is generated in the coil 3. The distortion due to the counterelectromotive force can be improved by constructing to return the output signal of the amplifier 2 to the input side of the amplifier 2 through a circuit element 5, so-called a negative feedback circuit, thereby reducing the harmonic wave in the axial direction between the rotor and the stator to perform the reduction in the noise. |
