Quartz watches and their forebears

Before we get into the nitty-gritty of Quartz Watches and the exactitudes of their functions, let’s cast a look back over a few of those failed antecedents alluded to previously.

In the days before the ‘discovery’ of quartz’s useful properties, horologists the world over attempted to harness the powers of electricity in watchmaking. The attraction was simple: electricity could provide a constant power source, unlike the variable tension delivered by a spring. Not even an automatic watch could pretend to contend with the possible uniformity of electric power, and so watchmakers, at first, did the obvious: they ripped out the barrel and replaced it with a battery, resulting in a short-lived generation of watches known as Motor Balance watches or, more simply, Electronic Watches.

Electronic watches, the Dynatron for example, are technically more accurate due to the consistency of the power provided to the mechanical balance by the battery (as opposed to the mainspring, which winds down and provides less and less power over time), but given that the time-keeping element of an electronic watch is still a mechanical balance, the difference in time-keeping is negligible.

A later, and somewhat more fondly remembered venture, resulted in Tuning Fork Watches. The Tuning Fork operated in a theoretically similar way to quartz, using the regular vibrations of a physical medium (in this case the fork as opposed to the quartz crystal) to ‘count’ the time.

Tuning fork watches, the Accutron, for example, are slightly more accurate due to the higher operating frequency.

So what is a Quartz Watch? A Quartz Watch is so named because of the sliver of genuine quartz crystal that, remarkably, plays the same role as the hairspring would in a mechanical watch. When a quartz crystal is properly cut (normally in the shape of a tuning fork) and mounted, it can be made to distort in an electric field by applying a voltage to an electrode near or on the crystal, distorting the crystal. This property is known as piezoelectricity. When the field is removed, the quartz will generate an electric field as it returns to its previous shape, and this can generate a voltage. The result is that a quartz crystal behaves like a circuit composed of an inductor, capacitor and resistor, with a precise resonant frequency.

This frequency (32,768 Hz) is equal to 2 to the power of 15 cycles per second. The frequency is ideal due to the fact that it can be stepped down cleanly to allow the wheels in the watch to easily translate that impulse into one tick per second. Some quartz watches do not have a seconds hand and thus do not need to tick every second. This enables the mechanical element of the quartz movement to operate less frequently, which in turn reduces the drain on the battery resulting in a longer lifespan.

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