Piezoelectric sensor application

2. Piezoelectric acceleration sensor
    Its structure generally has three types: longitudinal effect type, lateral effect type and shear effect type. The longitudinal effect is the most common, as shown in the figure. The piezoelectric ceramic 4 and the mass 2 are ring-shaped, and the mass is preloaded by the nut 

3 to be pressed against the piezoelectric ceramic. The sensor base 5 is firmly fastened to the object to be measured during measurement. The output signal is taken from the electrode 1.When the silver plating piezo cylinder sensor senses vibration, since the mass is relatively small with respect to the mass of the object to be measured, the mass feels the same vibration as the sensor base and is subjected to an inertial force opposite to the acceleration direction, and this force F=ma. At the same time, the inertial force acts on the piezoelectric ceramic sheet to generate a charge.

3. Measuring surface roughness with a piezoelectric sensor
   
       The figure shows the structure of the piezoelectric sensor when it is applied to the profiler. The sensor is dragged by the drive box so that the stylus slides at a constant speed on the surface of the workpiece. The undulation of the surface of the workpiece causes the stylus to move up and down, and the piezoelectric crystal is deformed by the needle bar. Thus, a charge is generated on the surface of the piezoelectric crystal, and the electrical output of the lead is proportional to the displacement of the stylus.

4. electronic gas stove ignition device
   
         The principle of the electronic ignition device of the gas stove is to use high-pressure flashover to ignite the gas. When the user presses the switch inward, the air valve is open; when the switch is rotated, the spring is pressed to the left; at this time, the spring has a large force striking the piezoelectric crystal, and a high-voltage discharge is generated,which is causing the combustion disk to ignite.

In engineering and machining, piezoelectric power sensors can be used to measure the impact of various mechanical equipment and components. For example, forging hammers, smashing machines, pile drivers, vibrating feeder vibration exciters, geological drilling rig impactors, ship, vehicle collision and other mechanical equipment impact force measurement,which can use piezoelectric power sensors.

Working principle of ultrasonic piezoelectric transducer sheet: When the piezoelectric ceramic sheet is subjected to external pressure, the ceramic sheet is mechanically deformed, and its polarization intensity is reduced, so that a part of the electric charge attached to the surface of the ceramic sheet is released, and a discharge phenomenon occurs. When the pressure is canceled, the original state is restored, the polarization intensity is increased, and a part of the electric charge is adsorbed on the electrode, and charging phenomenon occurs. This phenomenon of conversion from mechanical energy to electrical energy is called positive piezoelectric effect.