| 摘要 |
PROBLEM TO BE SOLVED: To provide the driving and detecting device for piezoelectric vibrator which enables the piezoelectric vibrator to output an output current with a constant amplitude without using an automatic gain control means. SOLUTION: When a driver resistance RD is interposed between a drive means 27 and a piezoelectric vibrator 11, a driving voltage VC can be determined by the division ratio of the drive resistance RD and the internal resistance Z of the piezoelectric vibrator 11. When the output current I1 tends to decrease at high temperature, the internal resistance Z increases and the drive voltage VC can be set large, so that the mechanical amplitude of the piezoelectric vibrator 11 increases. The decrease of the output current I1 due to the increase in the internal loss of the piezoelectric vibrator 11 is therefore compensated. At low temperature, the internal resistance Z becomes small and the drive voltage VC drops to the contrary, so the mechanical amplitude can be made small. The increase of the output current I1 of the piezoelectric vibrator 11 can be compensated. Namely, no AGC circuit is needed, so the trouble of an AGC circuit can be eliminated. |
