Crystal units are constructed from a high-stability piezoelectric quartz crystals that performs as a mechanical resonator. Crystal units have the capability to generate clock signals which are crucial for ICs and LSIs to function, and accomplish high stability, adjustment-free performance, and miniaturization. Currently, crystal units are used in a broad category of applications that includes mobile communication, communications satellite, TVs, automobile electronics, personal computing, and home communication appliances like DVD equipment. Therefore, with such properties, they can be used in many projects because they are capable of accomplishing many tasks. However, it is always crucial to be well informed regarding such products to ensure that they will work in your favour as you want them to.
Internal Structure of Crystal Units
In crystal units for effectively deriving the required energy, the energy can be changed by mechanical vibration to an electrical signal. The system that supports the crystal wafer must suppress the vibration by a minimum amount. In the internal structure of the thickness-sheer mode crystal unit at the lowest displacement of the mechanical vibration on the wafer.
Cutting Angles and Vibration Mode
The cutting angles of crystal units may vary depending upon the differences in applications. It also depends on the oscillation frequencies and electrical characteristics. The structure will include the main cutting angles, the vibration modes, frequency ranges, and capacity ratios.
For example, the most popular type of crystal wafer which are the AT-crystal wafer, the wafer plane is designed at an angle of f 35°15’ to the Z-axis. In this situation the fundamental wave thickness-shear vibration, which is 28 MHz, the thickness of wafer is about 0.6 mm.
Cutting Angles and Frequencies
Crustal units are widely used because of their stable frequency properties but they also exhibit superior temperature characteristics. However, the units made from ordinary materials are effected by temperature changes which result in the changing of oscillation frequency as well. now the relation between the changing frequency and the cutting angle is that the level of change in frequency varies accordingly to the cutting angle.
Frequency/Temperature Characteristics
The frequency or temperature properties of crystal units are different from those of the standard crystal oscillators installed. If the standard for frequency or temperature for the oscillation circuits is limited then some of the circuits will not meet those standards. This is because both the crystal units and oscillation circuits have temperature and frequency characteristics. Therefore, it is crucial to check the frequency/temperature characteristics of the oscillation circuits before working on them. after you check those characteristics, you can place an order for a crystal unit that can meet those frequency or temperature characteristics that can fix the differences.
Despite taking such careful measures if more strict specifications are needed then it is better to use a temperature compensated crystal oscillator.
Drive Level of a Crystal Unit
There are different mechanical oscillation modes of crystal units. However, there are some limitations imposed on the mechanical vibrations of a crystal unit. Due to this the frequency may be lost at certain temperatures or it may lead to a rise in the effective resistance of a crystal unit. Therefore, it is necessary to use the crystal unit at an appropriate drive level.
Conclusion
Crystal units may be hard to understand in terms of their structure, function, and operating conditions. However, they are not difficult to work with once you choose crystal units with the right specifications. to purchase crystal units, visit our website and choose among the wide variety of products available on our online shopping site.
