Difference Between Crystal and Resonator


Crystals and resonators are used as timing devices in electronics to generate precise and reliable signals for a variety of applications. Although they perform some of the same tasks, they differ in terms of construction, characteristics, and applications.

Crystals are made of piezoelectric material and vibrate at a given frequency, whereas resonators are made of a coil and capacitor and generate a resonant circuit that oscillates at a specific frequency.

Read this article to find out more about Crystal and Resonator and how they are different from each other.

What are Crystals?

When an electrical voltage is supplied to a crystal, it vibrates at a precise and stable frequency because it is made of a piezoelectric substance, often quartz. The piezoelectric effect describes the ability of some materials, like quartz, to generate an electrical charge when mechanical stress is applied and vice versa.

The piezoelectric effect is a phenomenon that occurs when certain materials, such as quartz, are subjected to mechanical stress or deformation. A moderate electrical voltage applied across a crystal causes mechanical deformation or vibration, which in turn produces an electrical voltage at a specific frequency. Because of this feedback mechanism, crystals provide a constant and exact oscillation frequency, making them excellent for generating accurate timing signals in electrical circuits.

Crystals have higher frequency stability and accuracy than conventional timing devices such as resonators or RC circuits. Crystals may produce timing signals with very low frequency drift and minimum phase noise, making them suitable for precision timing applications such as clocks, microprocessors, and communication systems. Crystals, on the other hand, might be more expensive and larger in size than other timing devices, which can be a disadvantage in particular applications.

Crystals of various varieties, such as AT-cut, BT-cut, and SC-cut, are available and optimized for certain applications based on temperature stability, frequency range, and ageing characteristics. The most often used crystals are AT-cut crystals, which have a temperature stability of a few parts per million (ppm) over a large temperature range. Communication systems, for example, use BT-cut crystals because they require higher frequency stability. SC-cut crystals, which have a temperature stability of a few parts per billion (ppb), are used in high- precision applications such as atomic clocks.

What are Resonators?

A resonator is an electrical component that consists of a coil and a capacitor that work together to create a resonant circuit that oscillates at a specified frequency. Resonators, unlike crystals, do not rely on piezoelectric properties and are not made up of solid-state materials.

The coil and capacitor in a resonator circuit are connected in parallel, which results in a tuned circuit that resonates at a given frequency. The resonant frequency is determined by the coil and capacitor situation and is relatively stable across a limited range of temperatures. Resonators have less frequency stability than crystals, but they are simpler and less expensive.

Microcontrollers, remote controls, and sensors all use resonators in electronic circuits that require reasonable frequency stability. The resonator in these applications produces a reliable clock signal that synchronises the operation of the electrical components.

Ceramic resonators, surface acoustic wave (SAW) resonators, and crystal oscillators with integrated capacitors (CXOs) are all examples of resonators. Ceramic resonators are the most popular and are often less expensive and smaller than crystal oscillators. Wireless communication systems, for example, use SAW resonators because they demand stronger frequency stability and lower phase noise. CXOs are crystal oscillators with in-built capacitors that provide a compromise between crystal stability and resonator simplicity.

Difference between Crystal and Resonator

The following table highlights the major differences between Crystal and Resonator −

Characteristics

Crystal

Resonator

Material used

Quartz (solid-state)

Coil and capacitor

Frequency stability

High

Moderate

Frequency accuracy

Excellent

Good

Operating principle

Piezoelectric effect

LC resonant circuit

Temperature stability

Good

Moderate

Cost

High Cost

Low Cost

Size

Larger

Smaller

Aging

Negligible

Moderate

Applications

High precision and stability applications (clocks, microprocessors, communication systems, frequency synthesizers)

Moderate precision and stability applications (microcontrollers, remote controls, sensors)

Conclusion

Both crystals and resonators are useful electrical components that are used as timing devices in a variety of applications. While crystals provide more frequency stability and accuracy due to their solid-state construction and piezoelectric capabilities, resonators are simpler and less expensive alternatives that are suitable for applications that require moderate frequency stability. The decision between the two depends on the application's specific requirements and the trade-off between cost, size, and performance.

Updated on: 15-May-2023

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