| 摘要 |
PROBLEM TO BE SOLVED: To control the frequency in correspondece with the change in environental conditions witout installing a motor electrode on a vibrating body by detecting the environmental or driving conditions at the time of driving and controlling the frequency of a cyclic signal according to the detection result. SOLUTION: A memory circuit 14 stores the program for controlling a vibration motor 9 and a table of data about the maximum speed which is available for each temperature. The voltage of a diode 16 is digitized by an A/D converter 17 and then is fetched in a microcomputer 1 to detect the temperature. The maximum speeds which are available for respective temperatures are compared by the memory circuit 14 and the vibration motor 9 is controlled always within a range wherein the vibration frequency may not exceed the resonance frequency even if the resonance frequency varies due to the change in temperature. By this method, there is no necessity of installing a motor electrode and the vibration motor 9 can be so controlled that the vibration frequency may not exceed the resonance frequency even if the characteristics of the vibration motor 9 change due to the change in temperature. |
