Crystal oscillator

Crystals Oscillators are used as means of generating an electrical signal at a specific frequency in Hertz. A processor may require an external reference signal as an input, and a crystal oscillator can serve as this reference. Crystals used in electronic circuits like this are frequently made of quartz. They are sold in a wide range of frequencies.

Operating Principles
Any elastic object can be used as a crystal, but must have the appropriate transducers. However, quartz is a relatively simple, inexpensive material with ideal properties for this purpose, and likewise, these properties fluctuate very minutely in response to most normal ambient conditions such a temperature and humidity.

Through the concept of piezoelectricity, a properly cut and mounted piece of quarts in an electric field will oscillate, generating a voltage that fluctuates at regular intervals. This functions like a basic timing circuit (resistor, capacitor, and inductor), but with a very precise frequency.