Posted tagged ‘40th birthday of quartz watches’

Quartz Watches: How, what & why

March 8, 2010

Briefly: Quartz watches are independent and will function without our attention

quartz watch

Quartz watches use a crystal of quartz (silicon dioxide) shaped like a small bar. This is a ‘piezoelectric’ material – when bent or compressed it generates a small electric field (and vice versa). The crystal is formed to have a natural oscillation at around 32,000Hz. These oscillations generate small electrical signals which are ‘divided down’ by the circuit within the watch to the required frequency (usually seconds) and translated into pulses which are sent to the watch display or a motor to move the seconds hand. The advantage of quartz watches is their simplicity and accuracy – crystals maintain their frequency over broad operating conditions and are cheap to make. They are battery powered and, because they use so little electricity, the battery can often last several years before you need to replace it.

Quartz watches have gears inside them to count the seconds, minutes, and hours and sweep the hands around the clockface. But the gears are regulated by a tiny crystal of quartz instead of a swinging pendulum or a moving balance wheel. Gravity doesn’t figure in the workings at all so a quartz clock tells the time just as well when you’re climbing Mount Everest as it does when you’re at sea.

Quartz sounds exotic, but it’s actually one of the most common minerals on Earth. It’s made from a chemical compound called silicon dioxide (silicon is also the stuff from which computer chips are made), and you can find it in sand and most types of rock. Perhaps the most interesting thing about quartz is that it is piezoelectric: if you squeeze a quartz crystal, it generates a tiny electric current. The opposite is also true: if you pass electricity through quartz, it vibrates at a precise frequency (it shakes about an exact number of times each second). Inside a quartz clock or watch, the battery sends electricity to the quartz crystal through an electronic circuit. The quartz crystal oscillates (vibrates back and forth) at a precise frequency: exactly 32768 times each second. The circuit counts the number of vibrations and uses them to generate regular electric pulses, one per second. These pulses can either power an LCD display (showing the time numerically) or they can drive a small electric motor (a tiny stepping motor, in fact), turning gear wheels that spin the clock’s second, minute, and hour hands.

Quartz watches gain or lose seconds here and there. Quartz vibrates at a slightly different frequency at different temperatures and pressures so its timekeeping ability is affected to a tiny degree by the warming, cooling, ever-changing world around us. In theory, if you keep a watch on your wrist all the time (which is at more or less constant temperature), it will keep time better than if you take it on and off (causing quite a dramatic temperature change each time).

Quartz watches are independent and will function without our attention. If we left it in a drawer for a year, it will still run. It will still be accurate we can take it for granted, and it does not need us. By nature, they are cool and aloof and so are our reactions, they fail to touch our hearts in the deepest sense.

Highlights

*Quartz watches completed its 40th birthday in December 2009

*Seiko introduced the world’s first quartz watch, called Quartz Astron

*Hamilton introduced the worlds’ first digital watch. The launch was delayed for two years after the watch’s unveiling at a press conference because it used too much power

*Citizen brought to market the first solar powered quartz watches

*In 1981 worldwide production of quartz watches surpassed that of mechanical one

*83.5 per cent watches exported from Switzerland in 2008 had quartz movements

*At 0.98mm Quartz powered Concord Delirium IV was the thinnest watch ever made