Quartz Crystal Technology

Quartz crystal technology is based on the piezoelectric properties of quartz, a crystalline form of silicon dioxide. Piezoelectric materials generate a small voltage when mechanically stressed and, conversely, deform when a voltage is applied to them. This two-way relationship between electrical and mechanical behaviour is the foundation of the quartz crystal as a precise frequency-determining component in electronics.

When a thin slice of quartz is cut and fitted with electrodes, it vibrates mechanically at a very stable natural frequency that depends on the dimensions and the angle of the cut. Driven by an electronic circuit, the crystal behaves like a highly selective resonator, far more stable than a circuit built only from inductors and capacitors. The sharpness of this resonance is described by the quality factor, or Q factor; quartz crystals have an extremely high Q, which gives them their precise and stable frequency. This stability is also relatively insensitive to temperature when an appropriate crystal cut is chosen.

Because of these properties, quartz crystals are used wherever an accurate and consistent frequency is needed. They set the timekeeping of quartz watches and clocks, provide the clock signal for microprocessors and digital systems, and stabilise the frequency of radio transmitters and receivers. The same piezoelectric principle underlies other devices, including ceramic resonators and certain sensors and ultrasonic transducers. Quartz crystal technology remains a fundamental building block of accurate timing in electronics.

Frequently asked questions

What is the piezoelectric effect?

It is the property by which certain materials, such as quartz, produce a voltage when mechanically stressed and deform when a voltage is applied to them.

Why are quartz crystals used for timing?

A quartz crystal vibrates at a very stable natural frequency with a high quality factor, providing a far more accurate and consistent reference than ordinary LC circuits.

What is the Q factor of a crystal?

The Q, or quality factor, measures how sharp and low-loss the resonance is. Quartz crystals have a very high Q, which underlies their excellent frequency stability.