Piezo Ceramic sheets used in ultrasonic transducers

When you are igniting a gas stove or water heater, there is a piezoelectric ceramic that has quietly served you once. In this type of piezoelectric ignition device, the manufacturer has a piezoelectric ceramic. When the user presses the spring of the ignition device, the transmission applies pressure to the piezoelectric ceramic, which causes it to generate a high voltage. The electric energy is directed to the outlet of the gas to discharge, so that the gas is ignited by the electric spark. This function of piezoelectric ceramics is called the piezoelectric effect. Conversely, when a voltage is applied, a mechanical stress is generated, which is called an inverse piezoelectric effect.

Brake pads can vibrate when they are in contact with the rotor during low-speed driving, sometimes as harsh noise. This noise does not affect the performance of the brakes, but it can result in the  unnecessary replacement of the brake pads and the addition of gaskets, sound-damping materials and other components to eliminate noise. If a simple piezoelectric ceramic actuator is installed in the brake piston of the car, a "jitter" frequency is applied to the support plate of the inner brake shackle to effectively suppress the vibration that generates sharp noise, thereby changing the temperature and humidity and braking. The system works in the event of normal wear and tear. Since there is no need to install a detector or logic system to determine the appropriate control frequency, such a device is much simpler in construction and requires fewer components.

Piezo disc vibration sensor can also be used knock sensor, an ultrasonic sensor, an acceleration sensor, and the like for automobiles. The piezoelectric ceramic of knock sensor is composed of a piezoelectric ceramic vibrator, a metal piece, a gasket, a metal case, and the like. The electric charge generated by the piezoelectric vibrator is proportional to the vibration generated by the engine cylinder. The generated voltage enters the electronic control unit through the shielded line, thereby detecting the voltage generated by the vibration of about 7 kHz.The electronic control unit judges the explosion according to the magnitude of the voltage. The intensity of the earthquake, timely correction or response to delayed ignition to eliminate knocking in advance, so that the engine works close to the knocking, the highest thermal efficiency, and the least is fuel consumption, to achieve the non-knocking working state, to ensure the maximum possible power and economic indicators of the engine. The running ultrasonic sensor is used as a vehicle reversing anti-collision alarm device, also known as an ultrasonic reversing radar or a reversing sonar system, and is particularly suitable for large-sized vehicles such as extended loading vehicles, heavy goods vehicles, and mining vehicles.

The ultrasonic sensor is usually composed of an aluminum alloy casing, a piezoelectric ceramic transducer, a sound absorbing material, and a lead electrode, and has a wide horizontal characteristic and a limited directivity in the vertical direction. In principle, a lead zirconate titanate PZT piezoelectric ceramic is used. The positive and negative piezoelectric effects that convert between electrical energy and mechanical energy, when an electric signal is applied to the piezo ceramic disc, which mechanical vibration emits ultrasonic waves. When the ultrasonic waves hit the obstacle during the air propagation, they are immediately reflected back. In the case of its ceramics, there will be an electrical signal output, through the data processing time difference ranging, calculate the distance between the vehicle and the obstacle and the alarm when the dangerous collision, can accurately detect the small obstacles of the car tail and the blind spot of the driver's perspective. The material is quite practical. In order to obtain high emission efficiency and acceptance sensitivity, the ultrasonic sensor that transmits and receives all together is the mainstream product on the market, and has high emission efficiency, receiving sensitivity and sharp directivity. Ultrasound piezoelectric ceramic disc has a certain angle and range of detection that covers the entire area behind the car. An ultrasonic sensor for measuring the distance between the chassis and the road surface of the vehicle electronically controlled suspension system is under development. The ultrasonic sensor is also used in an air flow meter to detect the amount of intake air of the engine.