# RF Wireless World

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## What is Quartz

This page describes what is quartz and mention quartz crystal oscillator basics.Link to quartz calculator is also provided.

The technical formula for quartz is referred as SiO2, which is composed of two elements viz. silicon and oxygen. The amorphous form of quartz is available in rocks as well as sand. They are abundant in nature but its highly pure form is needed for quartz crystal unit manufacturing. Quartz is a piezoelectric material, used for high frequency oscillation.

They are very important component of modern electronic industry. Quartz crystals are used to generate frequencies. They are widely used in clocks, computers, processors and watches.

### Quartz crystal equivalent circuit

Quartz resonators composed of piece of piezoelectric material fitted across crystallo-graphic axes. This wafer will have conductive electrodes which are formed by vacuum evaporation. The piezoelectric effect results when an E-field is applied between these electrodes. This will cause wafer to vibrate.

The figure-1 depicts Quartz crystal equivalent circuit. Where in Ls is inductance, Cs is series capacitance, Cp is parallel capacitance and Rs is series resistance.

### Quartz Crystal Parameters

Crystal oscillator operates in two modes series and parallel.

Q-factor: The equation/formula of Q-factor is mentioned above. Crystal offers very high Q factor approx. about 1 lakh.

Resonance: It is the condition when the voltage across a electronic circuit becomes in phase with the current supplied to the circuit. At resonance the circuit acts like a resistive circuit. Power factor of the circuit at resonance is equal to one.

Series resonance: This condition is formed using series connection of capacitor and inductor. Formula for series resonance frequency is mentioned above.

Parallel resonance: This condition is formed using parallel connection of capacitor and inductor. Formula for parallel resonance frequency is mentioned above.

Following are the steps involved in manufactutring of quartz crystal.
•  Cutting the wafers• lapping them• cleaning them•  checking orientation• rounding• cleaning and etching of blanks•  base plating• mounting• bonding• final adjustment of frequency using vaccum deposition of silver/gold• sealing holder to the can• prevention of electrode oxidation • high temperature cycling• high vacuum bake cycling• frequency control and sorting

### Quartz Crystal Parameter calculator

The Quartz calculator calculates Q-factor, series resonance frequency, parallel resonance frequency and crystal pulling factor.
REFER CALCULATOR PAGE➤

Following links refers to crystal oscillator manufacturers, difference between crystal oscillator and synthesizer. It also mentions types of oscillators such as OCXO, VCXO, TCXO and DCXO.
crystal oscillator manufacturers
crystal oscillator vs frequency synthesizer
OCXO vs VCXO vs TCXO vs DCXO
What is Quartz Crystal