Quartz crystals
Summary
The article explains how quartz crystals are used for stable oscillation and filtering, covering the crystal's physical structure and the common equivalent circuit (Lm, Cm, Cp, Rm). It explains series and parallel resonance, the role of external capacitance in setting parallel resonance, and how the piezoelectric effect enables the crystal to transform mechanical motion into electrical signals. It also discusses how open/short conditions and stray capacitance affect resonance, with references to related sources.