| 摘要 |
PURPOSE:To detect a pressure with the measured value of a current made to flow or of a voltage impressed to a piezoelectric bimorph by leading out a friction effect between an air and the piezoelectric bimorph in the manner of making the piezoelectric bimorph itself to a tuning fork structure. CONSTITUTION:First, if any of electrical signals is impressed to the piezoelectric bimorph 1 which is composed of the tuning fork structure connected to a terminal pin 5, signal components of the natural frequency of the tuning fork is conveyed to an electrical conductivity holding body 2 and the oscillation is propagated to the piezoelectric bimorph 1 on another side. In the result, the generated piezoelectric signal is conducted to an amplifier 16 passing through a connecting point 12, lead wire 6 and terminal pin 4, and after amplified there, transmitted to an automatic gain amplifier 17, further, an oscillation circuit having a circuit loop which is returned to the connecting point 11 of the piezoelectric bimorph 1 through a power amplifier 18, is formed and made to oscillate with a specified oscillation intensity. When the pressure is varied, it is indicated as the change of the voltage impressed to the connection part 11 of the piezoelectric bimorph, in the result that a resonance impedance of the tuning fork part is varied. |
