Piezoelectric ceramic tablets, commonly known as bee-ming tablets. Piezoelectric ceramic chip is an electronic sound element, in the two pieces of copper circular electrodes into the middle of piezoelectric ceramic dielectric material, when the two electrodes connected to the AC audio signal, the piezoelectric film will be based on the size of the signal frequency of vibration and produce the corresponding sound. Piezoelectric ceramic chip because of the simple structure of low-cost, is widely used in electronic appliances such as: toys, pronunciation of electronic watches, electronic equipment, electronic clocks, timers and so on. The ultrasonic motor is made by the related properties. Crystal oscillator is called crystal oscillator, its function is to produce the original clock frequency, this frequency after the frequency generator to enlarge or shrink into the computer a variety of different bus frequencies. Take the sound card as an example, to achieve the analog signal to the data. 1kHz or 48kHz sampling, the frequency generator must provide a single, 1kHz or 48kHz clock frequency. If you need to support both of these audio, the sound card requires two crystal oscillators. But the entertainment class sound card in order to reduce the cost, usually using SRC will output the sampling frequency fixed in 48kHz, but SRC will damage the sound quality, and now the entertainment level sound card has not solved this problem very well. Crystal oscillator is generally called Crystal resonator, is a kind of electromechanical devices, is a small loss of power of quartz crystal by precision cutting grinding and plating electrodes on the welding wire made. This crystal has a very important characteristic, if give it power, it will produce mechanical oscillation, conversely, if give it mechanical force, it will produce electricity, this kind of characteristic is called electromechanical effect. They have a very important characteristic, their oscillation frequency is closely related to their shape, material, cutting direction and so on. Because quartz crystal chemical property is very stable, the coefficient of thermal expansion is very small, its oscillation frequency is very stable, because the control geometry can be very precise, therefore, its resonant frequency is also very accurate. According to the electromechanical effect of quartz crystals, we can be equivalent to a electromagnetic circuit, that is, resonant circuit. Their electromechanical effect is machine-electricity-machine-electricity. The constant conversion, the resonant circuit composed of inductance and capacitance is the constant conversion of the electric field-magnetic field. The application in the circuit is actually regarded as a high Q value electromagnetic resonance circuit. Because the loss of quartz crystal is very small, that is, the Q value is very high, do the oscillator, can produce very stable oscillation, for the filter, can obtain very stable and steep cutting band-pass or band-stop curve.