Quartz crystal oscillatorgrm36x7r273k50ptStructure, characteristic and equivalent circuit
Structure of 1. quartz crystal oscillator
Quartz crystal oscillator is a kind of resonant device which is made of the piezoelectric effect of quartz crystal (silica crystal). Its basic composition is roughly as follows: slice from a quartz crystal according to a certain azimuth (abbreviated as wafer), it can be square, rectangular or circular, etc.), in its two corresponding. Silver coated on the surface of the electrode, each electrode welded a lead to the pin, coupled with the package shell to form a quartz crystal oscillator, referred to as quartz crystal or crystal, crystal oscillator. Its products are usually packaged in metal housing, but also in glass, ceramic or plastic packages. Fig. 3-12 is a schematic diagram of a quartz crystal structure encapsulated by a metal case.

                       
2. piezoelectric effect
Quartz crystal can be used as an oscillator because quartz crystal has piezoelectric effect. If an electric field is applied to two electrodes of a quartz crystal, the wafer will undergo mechanical deformation; otherwise, if mechanical pressure is applied to both sides of the wafer, an electric field will be generated in the corresponding direction of the wafer. This physical phenomenon is called piezoelectric effect. If alternating voltage is applied to the two poles of the wafer, the wafer will produce mechanical vibration, and the mechanical vibration of the wafer will produce alternating electric field. In general, the amplitude of mechanical vibration and the amplitude of alternating electric field are very small, but when the frequency of the external alternating voltage is a certain value, the amplitude is obviously increased, which is much larger than the amplitude of other frequencies. This phenomenon is called piezoelectric resonance. It is very similar to the resonance phenomenon of LC circuit. Its resonant frequency is related to the cutting mode, geometry and size of the wafer.