| 摘要 |
PURPOSE:To reduce the power consumption without creating any changes in a state by detecting the generation of signal changes by the proper use of an intermittent charge and a continuous charge. CONSTITUTION:A light emitting element 1b and a photodetecting element 1c are oppositely arranged, and the slits of a code board 1a which rotates as a machine travels are placed between them. Light emitted from the light emitting element 1b reaches the photodetecting element 1c. In a state of an intermittent charge, the light emitting element 1b emits light when receiving the supply of a source power per cycle DELTAt by the interval signals from an oscillator 1f through a switching device 1d, and sends the light toward the photodetecting element 1c. At this juncture, if the code board 1a does not rotate at all, there is no change in the output of the photodetecting element 1c per DELTAt. Now, if there is a shift from the absent to the present or the present to the absent of the slit of the code board 1a, the signal from the photodetecting element 1c to a signal retaining circuit 1g changes per DELTAt before and after such shift. The intermittent charge is switched over to a continuous charge by this change. In this way, it is possible to prevent the power to be consumed and avoid any wasteful consumption of a cell. |
