| 摘要 |
PURPOSE:To make a circuit electronically operated and extend the life, by providing a comparator, which detects the output voltage of a potentiometer connected directly to a motor with a set voltage, and a transistor TR which is connected to the output of this comparator and controls normal/reverse rotation of the motor. CONSTITUTION:When an angle changeover switch is switched to 180 deg., a TR21 is turned on, and an output voltage V2 of a comparator 15 becomes high, and a TR17 is turned off, and a TR18 is turned on. Simultaneously, an output voltage V3 becomes low, and a TR19 is turned on, and a TR20 is turned off, and then, a motor 7 is rotated to move a damper 8 to the position of 180 deg.. That is, a positive-direction current I is flowed to the motor 7, and an output voltage V1 of a potentiometer 9 rises; and when this output voltage exceeds a comparison voltage V4 of the comparator 15, the voltage V2 is changed from the low level to the high level, and the current I becomes zero to stop the motor 7. A negative-direction current is flowed to the motor 7 even if it exceeds the voltage V4 considerably because of some cause, and the damper 8 is moved until the voltage V1 coincides with a comparison voltage V5 of a comparator 16. |
