A Crystal is an electronic component that vibrates mechanically when an AC signal is applied. The most familiar type is quartz crystals which are much more accurate and temperature stable than ceramic resonators. Crystals are usually made of quartz and resonators are made from ceramic elements rather than quartz. Types of Crystals/Resonators include; Ceramic Resonators, Dielectric Resonators, Quartz Crystals, and SAW Resonators.
