Function: They are used as frequency-selective elements in crystal oscillator circuits to generate precise and stable clock signals in electronic devices. Applications: Crystals are found in a wide range of electronic applications, including microcontrollers, communication devices, digital systems, computers, mobile phones, and GPS receivers. Types: The image shows different types of crystals, likely varying in package size (e.g., HC-49U) and specific frequency (e.g., 27.00 MHz, 5.120 MHz, 7.374 MHz, 33.87 MHz). Availability: These components are widely available from electronics suppliers and online retailers specializing in electronic parts. MCG Technology™ Aug 2024.