Horological Meandering

Chemically, quartz is a specific form of a compound called silicon dioxide. Quartz is a piezoelectric material: that is, when a quartz crystal is subject to mechanical stress, such as bending, it accumulates an electrical charge across some of its planes as the molecules slide against each other. For example, crystals were used in low-end phonograph (record player) cartridges: The movement of the stylus (needle) flexes a quartz crystal, which produces a small voltage, which is amplified and played through speakers. The reverse effect, also holds true; if an electrical charge is fed into across the crystal, it will bend. 

A Quartz Crystal is generally used as the frequency determining device in a watch. When a voltage source is applied to a specially-trimmed, thin piece of quartz crystal, it begins to change shape producing a piezoelectric effect. When the physical size and thickness of a piece of quartz crystal is tightly controlled and fed an electrical current, we make it produce specific vibrations, known as the crystals “characteristic frequency”. Once cut and shaped, the crystal only operates at that frequency; its size and shape determine its constant output. 

For watches, 32768 is the normally-used frequency. Why? Because 32768=  2¹⁵  (32768 divided by 2, 15 times) equals one pulse per second. A small circuit does the dividing work, and the resulting pulse moves a tiny motor which moves the second hand, and through a train of gears, the minute and hour hands.

The Chronomaster shown here is accurate to +/- 5 seconds per year. 

If you really want to learn more, this Wikipedia Article will help you (or put you to sleep)...

Quartz watches can be very cheap and produced by the millions:

The crystal is in the vertical metal case.






Cheers,

Cazalea

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