Piezoelectric transducer. General scheme of the device
Direct piezoelectric effect, which is used in converters, is the appearance of electrical charges on the surface of some crystalline dielectrics (quartz, barium titanate) under the influence of mechanical stresses or deformations.
For Fig.1 a diagram of a piezoelectric transducer device for measuring gas pressure is shown.
The measured pressure P acts on the membrane - the bottom of the Converter housing. Two quartz plates are clamped between three metal gaskets. A ball is placed between the housing cover and the upper gasket to ensure uniform distribution of the measured pressure. To the middle gasket - negative electrode - attached wire passing through the insulation sleeve.
The potential difference between the negative electrode and the body is proportional to the measured pressure. The pressure is determined by the measured potential difference.
Since the charges disappear when removing the pressure, it is necessary to have a good isolation of the negative electrode so that during the measurement the charge does not have time to significantly change its value.
The negative electrode is connected to the grid of the first lamp of the amplifier, at the output of which the oscilloscope can be switched on.