Quartz crystals have several applications in the electronics industry. However, they are mostly used as resonators in electronic circuits. Quartz is a naturally occurring form of silicon. However, it is now produced synthetically to meet the growing demand. It exhibits the piezoelectric effect. If you apply physical pressure on one side, the resulting vibrations generate an AC voltage across the crystal. Quartz crystal resonators are available in many sizes according to the required applications.
1. Composition
As mentioned earlier, quartz crystals are either synthetically manufactured or occur naturally. They are often used to make crystal oscillators to create an electrical signal with a precise frequency. Usually, the shape of quartz crystals is hexagonal with pyramids at ends. However, for practical purposes, they are cut into rectangular slabs. The most common types of cutting formats include X cut, Y cut, and AT cut. This slab is placed between two metal plates called holding plates. The outer shape of a quartz crystal or crystal oscillator can be cylindrical, rectangular or square.
2. How Does It Work?
If you apply an alternating voltage to a crystal, it causes mechanical vibrations. The cut and the size of the quartz crystal determine the resonant frequency of these vibrations or oscillations. Thus, it generates a constant signal. Quartz oscillators are cheap and easy to manufacture synthetically. They are available in the range from a few KHz to a few MHz. As they have a higher quality factor or Q factor, crystal oscillators are remarkably stable with respect to time and temperature.
3. Function and Significance
The exceptionally high Q factor enables you to use quartz crystals and the resonant element in oscillators as well as filters in electronic circuits. You can find this highly reliable component in radio frequency applications, as oscillator clock circuits in microprocessor boards, and as a timing element in digital watches as well.
Quartz Watches
The problem with traditional coil spring watches is that you have to keep winding the coil periodically. Pendulum watches, on the other hand, depend on the force of gravity. Thus, they tell time differently at different sea levels and altitudes due to changes in the gravitational force. The performance of quartz watches, however, is not affected by any of these factors. Quartz watches are battery-powered. Usually, a tiny crystal of quartz regulates the gears that control the second, the minute, and the hour hands. As quartz watches use very little energy, the battery can often last longer.
Filters
You can also use quartz crystals in an electronic circuit as filters. They are often used to filter out unwanted signals in radios and microcontrollers. Most basic filters consist of a single quartz crystal. However, advanced filters may comprise more than one crystal to match the performance requirements. These quartz crystal filters are far superior to the ones manufactured using LC components.
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