| 摘要 |
<p>PURPOSE:To increase the electromagnetically braking force for a motor by shunting a current caused by the counterelectromotive force produced by the inertial revolution of the motor via two transistors and operating one of the transistors as a reverse transistor. CONSTITUTION:A motor M for a tape recorder or the like is connected between the connecting points of P-N-P transistors Q30, A40 and N-P-N transistors Q10, Q20, the Q30, Q20 are conducted at normal revolution by a controlling circuit 32, and the Q40, Q10 are conducted at reverse revolution, thereby driving the motor M. Further, the Q10, Q20 or the Q30, Q40 are conducted to shunt the counterelectromotive force current caused by the inertial revolution at braking time, thereby electromagnetically braking the motor. Since the braking current flows through the transistor having less voltage drop and the collector and emitter path of the reverse transistor, it can effectively brake the motor until the counterelectromotive force of the motor is considerably reduced.</p> |
