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Crystal oscillators can be manufactured for oscillation over a wide range of frequencies, from a few kilohertz up to several hundred megahertz.Many applications call for a crystal oscillator frequency conveniently related to some other desired frequency, so hundreds of standard crystal frequencies are made in large quantities and stocked by electronics distributors.
Quartz is one member of a family of crystals that experience the piezoelectric effect.The piezoelectric effect has found applications in high power sources, sensors, actuators, frequency standards, motors, etc., and the relationship between applied voltage and mechanical deformation is well known; this allows probing an acoustic resonance by electrical means.
The cron command-line utility is a job scheduler on Unix-like operating systems.Users who set up and maintain software environments use cron to schedule jobs [1] (commands or shell scripts), also known as cron jobs, [2] [3] to run periodically at fixed times, dates, or intervals. [4]
Quartz crystals are piezoelectric, so their mechanical characteristics can affect electronic circuits (see mechanical filter). In particular, quartz crystals can exhibit mechanical resonances with a very high Q factor (from 10,000 to 100,000 and greater – far higher than conventional resonators built from inductors and capacitors).
Mechanical boxed Marine Chronometer used on Queen Victoria's royal yacht, made about 1865 Omega 4.19 MHz (4 194 304 = 2 22 high frequency quartz resonator) Ships Marine Chronometer giving an autonomous accuracy of less than ± 5 seconds per year, French Navy issued,1980
By the end of the 1970s and into the early 1980s the industry had made such advances in quartz watch technology that Omega were producing 18-carat models which were less than 2mm thick (the dinosaur) which were accurate to 5 seconds per month, as shown in the attached image of watches, which is a stark demonstration of how far quartz technology ...
The following table lists the following properties for piezoelectric materials The piezoelectric coefficients (d 33, d 31, d 15 etc.) measure the strain induced by an applied voltage (expressed as meters per volt).
The quartz thermometer is a high-precision, high accuracy temperature sensor. It measures temperature by measuring the frequency of a quartz crystal oscillator.The oscillator contains a specially cut crystal that results in a linear temperature coefficient of frequency, so the measurement of the temperature is essentially reduced to measurement of the oscillator frequency.