Q Thequalityis theratio of energy storedtoenergyscatteringatresonances.Typical values are25000-300000.
Capacitance ratior
is acharacteristic ofthe waveformandthequartz crystal cutsize.Itdescribesthe sensitivity of therated frequencyto changes in theparameters in theexternalresonant circuit.ForAT-cutcrystals, the valueis typically at250.Forovertone:
Series resonance frequency f is the frequency for which the reactance is Zero
Parallel resonance fp is the frequency at which the reactance is infinitely
Load capacitance C1 takes into account the influence of reactances, the phase rotation and the duration of the resonator circuit on the resonant frequency.
Load resonance frequency f1 is the frequency at which the reactance of the series connection of quartz, and load capacity is zero.
Load resonance resistance RL the resistance of the series circuit of quartz crystal and load capacitance with RL> R1
Drawing area The frequency of a crystal can be slightly influenced by the Varation the load capacity. With CL1 and CL2 as minimum as the maximum value of the load capacitance is obtained for small changes.
Pulling sensitivity is the relative change in frequency for a given change of the load capacity expressed in 10-6 / pF, is given by:
Temperature dependence of the frequency For the AT-cut, the temperature dependence in the working area can be represented by a cubic equation, which is the cutting angle of the crystal dependent. The reference temperature is typically T = 25 ° C.
Operating temperature range Temperature range in which the parameters of the crystal, in particular its resonance frequency, are within the specified tolerances.
Temperature range of operability Temperature range in which the crystal can be operated, but not necessarily comply with the specified tolerances.
Temperature range of the shelf life Temperature range in which the quartz (current) can be stored, without changing its specifications.
Quartz nominal load Nominal load at which the quartz has been factory aligned to the nominal frequency. It is expressed as a power or voltage to a specified resistance.
Aging Under aging one understands the relative frequency change in a given period. The biggest change occurs during the first weeks after production Thereafter, the aging decreases exponentially with time. The relative frequency change is given as reading on 2 and 31 days. In the time between the measurements of quartz is stored unloaded at temperatures of 85 ° C. For commercial Crystals applies:
Frequency tolerance indicates the total deviation from the nominal frequency. It includes: - The balance tolerance - The temperature-dependent frequency change - The time-dependent frequency change - The frequency change by electrical load - The frequency change by defined mechanical stress
Balance tolerance is approved, production-related deviation from the nominal frequency. It is as a relative value for a given temperature, generally 25 ° C, specified. Defaults AT-cut quartz crystals are: / -50ppm / -30ppm / -20ppm and / -10ppm.