| 摘要 |
PURPOSE:To drive a motor at a constant voltage and remove flutter components by constituting a drive circuit for affording a control signal to the motor so that it has a low impedance output. CONSTITUTION:The high-frequency component of a signal delivered to a motor drive circuit 17 is removed by means of a low-pass filter constituted by resistors 12, 13 and a capacitor 14, and applied as a signal responsive to the phase difference between the reference signal and the speed of a motor 6 to a buffer transistor 15. The output of the buffer transistor 15 is current-amplified by a motor drive circuit 17, and rotates the motor 6 at a constant speed. In the motor drive circuit, an amplifier is formed by an operational amplifier 18 and a transistor 19, and the motor 6 is connected to the emitter of the transistor 19. A negative feedback is applied to the inversion input of the operational amplifier 18, and the amplification degree of the entire system is set and stabilized. |
