| 摘要 |
PURPOSE:To detect the presence of the rotation of a motor and to control the speed of the motor with a simple construction by detecting a motor noise. CONSTITUTION:When a signal shown in a waveform A from the collector of a transistor Q6 is applied as a motor noise through an inverter 1NV, a transistor Q7, an operational amplifier Q8 to a low pass filter made of a resistor R9 and a capacitor C3, a smoothed signal shown in the waveform E is obtained. When the rotating speed of a reel motor RM is accelerated, the motor noise generated at the collector of a transistor Q1 is increased proportionally to it, resulting in an increase in the voltage level of the signal E. Thus, the base voltage of a transistor Q3 is increased to reduce the ON resistance between the collector and the emitter. Thus, the emitter voltage of the transistor Q1 is dropped to decelerate the speed of the motor RM. |
