Crystal oscillator

IEEE 315 Fundamental Items Symbols (113)

18MHZ 12MHZ Crystal 110

Early NBS crystal oscillator frequency standards

Crystal Units Frequency Standard Oscillator XO VCXO OCXO TCXO Bell Labs AT&T Vectron

Crystal modes multilingual

Crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency. This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as "crystal oscillators."

Types of Crystal Oscillators

There are several types of crystal oscillators, including:

• AT Cut: The most common type used in most applications due to its temperature stability.
• BT Cut: Offers better temperature stability than AT cut but is less common.
• SC Cut: Offers superior temperature stability and aging characteristics, used in high-performance applications.

Operating Principle

The basic principle behind the crystal oscillator is the piezoelectric effect. When a mechanical stress is applied to a piezoelectric material such as quartz, it generates an electrical charge. Conversely, when an electrical field is applied, the material changes shape. This property allows the crystal to oscillate with a precise frequency when placed in an oscillator circuit.

Applications

Crystal oscillators are used in many types of electronic devices. Some common applications include:

• Clocks and Watches: Utilizing the high precision of crystal oscillators to keep accurate time.
• Computers and Mobile Phones: Providing the clock signal for microprocessors and memory units.
• GPS Receivers: Offering the precise timing required for satellite communication.
• Radio Systems: Stabilizing the frequency of the transmitter and receiver circuits.

Advantages and Disadvantages

Advantages:

• High precision and stability
• Low cost for the level of accuracy provided
• Small size and low power consumption

Disadvantages:

• Susceptible to physical stress and environmental conditions, which can affect frequency
• Limited tuning range compared to other types of oscillators

See Also

• Piezoelectricity
• Electronic oscillator
• Quartz clock
• Radio frequency