| 摘要 |
PROBLEM TO BE SOLVED: To exactly detect a rotational speed and the number of revolutions of a brush-type DC motor with a simple and spaceless configuration, and to effectively control the rotation. SOLUTION: A DC motor M1 comprises a rotation-detection brush BD1 adding to electrode brushes B11 and B12. A rotation-detection signal obtained by the rotation-detection brush BD1, wherein a noise-elimination circuit 1 eliminates noise, is fed to a differentiation circuit 2, and a differentiation pulse that responds to a leading edge is generated. A pulse generator 4 is triggered through an amplifier 3 by an output-differentiation pulse of the differentiation circuit 2. The pulse generator 4 generates a pulse having a regular pulse-time width and outputs a pulse train having a pulse space that is inversely proportional to a rotational angle speed. |
