| 摘要 |
PURPOSE:To make possible reversing rotation using one capstan by generating a pulse when an overload condition continued for longer than a certain length of time to actuate a flip-flop circuit thereby reversing the rotating direction of a motor. CONSTITUTION:An armature current of a direct current motor 1 that drives a capstan used in a magnetic record reproduction device is detected by a resistor 10 in an overload detector circuit 4, which controls transistors 11, 16 to produce an output with a resistor 18, a condenser 19 and a Zener diode 20 when an overload lasts longer than a certain length of time. This output is fed to a flip-flop circuit 3 to be inverted which in turn changes the direction of the current of the motor 1 hence the direction of the rotation of the motor. One capstan thus automatically performs reversing action utilizing increase of the load of the motor 1 at the end of a tape. |
