What are crystals? Crystal oscillator and crystal unit?

A crystal oscillator is an electromechanical device and an electronic oscillator circuit. The primary purpose of an oscillator is to make use of a quartz crystal as a frequency. The crystal oscillator uses the mechanical resonance of a vibrating crystal, which is made up of a piezoelectric material.

This process allows the oscillator to create and obtain an electric signal with a high precision frequency.

Quartz crystal units are used as resonators in crystal oscillator circuits.

Crystals have tight tolerance, accurate frequency, and long-term stability. Crystals’ wide range of frequencies is to provide the clock source. Specifications include resonance frequency, resonance mode, load capacitance, and series resistance. The oscillation mode in the resonance frequency operation is specified at the fundamental frequency or the third overtone.

How is a crystal made?

The most common material for manufacturing oscillator crystals is quartz. Natural quartz crystals were used at the beginning of the technology. Still, synthetic crystalline quartz grown by hydrothermal synthesis is predominant due to higher purity, lower cost, and more convenient handling.

  • Crystal oscillators are considered superior to ceramic resonators, which is for many reasons. They offer higher stability, higher quality and are considerably lower in cost and more compact.

  • Quartz crystals are produced so that frequencies range from a few tens of kilohertz up to hundreds of megahertz.

How does a crystal work?

Crystals have two resonance modes, series, and parallel. When using parallel-resonant oscillation mode, load capacitance is an important specification. Oscillator circuits can tolerate some degree of series resistance. Various ceramic epoxy, metal, and plastic packages for crystals offer excellent environmental and heat resistance. Applications of a crystal are found in mobile phones, clock circuits for microprocessors, GPS clocks, and ISM band radio frequency communications.

What are the applications of crystals?

Crystal oscillators are compact and are of low cost. Hence, their common application is in various fields, including electronic warfare systems, communication systems, guidance systems, microprocessors, microcontrollers, space tracking systems, measuring instruments. Also, we can find crystals in most medical devices, computers, digital systems, instrumentation, phase-locked loop systems, modems, sensors, disk drives, marine systems, telecommunications, engine control systems, clocks, Global Positioning Systems (GPS), cable television systems, video cameras, toys, video games, radio systems, cellular phones, timers, and so on.

How are crystal oscillators used?

The frequency with a crystal oscillator is mostly used to keep track of time within a wristwatch or a digital integrated circuit to provide a stable clock signal. This is where this signal gained its commonly referred to name “clock signal.” This clock signal is used to synchronize the other electronic devices that make up the oscillator system. An oscillator is also used to help stabilize frequencies for radio transmitters and receivers, used in clocks (clock oscillator), computers, and cell phones. Quartz crystals can also be found inside test and measurement equipment such as counters, signal generators, and oscilloscopes.

What are different types of Crystal Oscillators?

  • TCXO – These are used when temperature stability is needed and can’t be attained through a standard crystal oscillator (X.O.) or a voltage-controlled crystal oscillator (VCXO).

  • OCXO – This is an oven-controlled crystal oscillator, a type of oscillator that achieves the highest frequency stability that a quartz crystal can. They are designed to operate inside a temperature-controlled oven. They are larger and require more power to function.

  • VCXO – This is a voltage-controlled crystal oscillator. It controls crystal output changes by using a D.C. (direct current) voltage.

Who manufactures crystals?

  • Epson Electronics

Japan’s Seiko Epson Corp. was merged in 1998 to North American sister operations Epson Electronics America Inc. to consolidate the parent company’s businesses in the Americas.

  • KDS

KDS America is a subsidiary of Japan’s Daishinku Corp., which has relocated its U.S. headquarters to Atlanta.

  • American KSS

Like most component suppliers in 1998, American KSS Inc. had to deal-and is continuing to deal with severe price erosion. Revenue last year decreased even as unit shipments continued to climb, said Wayne DeBord, vice president of sales at the Santa Clara, Calif.-based subsidiary of Kinseki Ltd., Kanagawa, Japan.

  • NDK

NDK America Inc., the U.S., is a branch of Japan’s Nihon Dempa Kogyo Co. Ltd.

  • SaRonix

SaRonix Corp. has put significant effort into sales and marketing organizations in the past years, especially in Europe. The company has its sales offices in Germany, France, United Kingdom, and the Netherlands.

  • Toyocom

Toyocom U.S.A., Arlington Heights, Ill. is a unit of Japan’s Toyo Communication Equipment Co. Ltd. The company manufactures crystal products for several market segments, including computers, instrumentation, automotive, communications, and satellite.

Where to buy crystals?

Customers can buy crystals from the original manufacturers or reliable electronic distributors. B.D. Electronics is a distributor that can provide customers with all types of crystals and a wide range of electronic components. 

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