Editing Crystal oscillator (section)

=== Mechanical stress ===
Mechanical stresses also influence the frequency. The stresses can be induced by mounting, bonding, and application of the electrodes, by differential thermal expansion of the mounting, electrodes, and the crystal itself, by differential thermal stresses when there is a temperature gradient present, by expansion or shrinkage of the bonding materials during curing, by the air pressure that is transferred to the ambient pressure within the crystal enclosure, by the stresses of the crystal lattice itself (nonuniform growth, impurities, dislocations), by the surface imperfections and damage caused during manufacture, and by the action of gravity on the mass of the crystal; the frequency can therefore be influenced by position of the crystal. Other dynamic stress inducing factors are shocks, vibrations, and acoustic noise. Some cuts are less sensitive to stresses; the SC (stress-compensated) cut is an example. Atmospheric pressure changes can also introduce deformations to the housing, influencing the frequency by changing stray capacitances.

Atmospheric humidity influences the thermal transfer properties of air, and can change electrical properties of plastics by diffusion of water molecules into their structure, altering the [[dielectric constant]]s and [[electrical conductivity]].<ref>[http://www.ieee-uffc.org/frequency_control/teaching.asp?vig=vigstab Frequency Control|Teaching Resources] {{webarchive|url=https://web.archive.org/web/20100705235900/http://www.ieee-uffc.org/frequency_control/teaching.asp?vig=vigstab |date=2010-07-05 }}. Ieee-uffc.org. Retrieved on 2010-02-08.</ref>

Other factors influencing the frequency are the power supply voltage, load impedance, magnetic fields, electric fields (in case of cuts that are sensitive to them, e.g., SC cuts), the presence and absorbed dose of γ-particles and ionizing radiation, and the age of the crystal.