Why quartz in watches

For many, this was as simple as getting up when it rose and going to bed when it set. Many people used sundials, which could have been as simple as a stick in the ground, to keep track, but these were useless without sunshine which is often the reality in the UK! Pendulum clocks were the first form of precision timekeeping that were widely used.

An Italian polymath called Galileo Galilei studied the way a pendulum swung and discovered that it could be used to regulate time in a clock. This idea was taken up by a Dutch scientist called Christiaan Huygens and in he designed and built the first ever pendulum clock. A weight on the end of the pendulum regulates its swinging. As it reaches its highest point, it has lots of potential energy. Due to gravity, potential energy is then transferred into kinetic energy movement.

The weight then reaches the other side and the process repeats. Energy is repeatedly transferred in order to keep a regular rhythm. A pendulum could be designed to swing to the exact time to mark seconds. Oscillators are essential to every form of timekeeping, including quartz watches. Oscillators cause a repeating back and forth movement of energy. In other words, a regulated and repeating movement like the swinging of a pendulum. Their predictable pattern can therefore be used to measure time.

The issue with pendulums is around accuracy and upkeep. There are lots of factors that mean that kinetic energy decreases, such as air resistance. Eventually, the clock will slow down and become inaccurate. Pendulum clocks needed to be wound up regularly to keep the time accurately. Pendulums had to be kept in one place in order to maintain their rhythm, so a new mechanism was required to create a portable oscillator to power a watch. The first portable watch mechanism resulting in the invention of the pocket watch around the 17th century.

These watches worked with a spring that was wound up tightly to provide power as it slowly uncoiled. Like with the harmonic oscillator in the pendulum clock, which transferred different forms of energy back and forth repeatedly, the oscillating mass in a pocket watch had the same job. This is the part of the watch that keeps the steady rhythm and is also essential to the way a quartz watch works. The more accurate and controlled this is the better the watch. However, the balance spring and the balance wheel were invented.

These oscillated at a fixed resonant frequency. Or in other words, the oscillator movement was more regular and therefore more accurate than ever before. The movement was more predictable and stayed regular for longer, so better kept track of the time. There was one issue though; you had to remember to wind your watch! If you forgot, the watch mechanisms would stop oscillating and the watch would no longer record the time.

It would slow down, then stop. In order for this to happen, watch makers had to wait for the discovery of electricity and the invention of batteries.

These are combined with quartz to create the watches we use today. In , Jacques and Pierre Curie discovered that quartz had some amazing properties. JavaScript seems to be disabled in your browser.

For the best experience on our site, be sure to turn on Javascript in your browser. First developed in the late s, quartz watches are a relatively new phenomena in the centuries-old craft of watchmaking.

Unlike watches with mechanical movements, quartz watches are a whole different breed. Essentially, a quartz watch is battery powered. The watch uses a low-frequency, tiny piece of quartz crystal silicon-dioxide placed either like an integrated circuit and chemically etched into shape, or shaped like a tuning fork.

That quartz crystal serves as the oscillator. The battery sends electricity to the quartz crystal through an electronic circuit. The circuit counts the vibrations and generates regular electric pulses of one per second. The difficulty was in the selection of the integrated circuit technology that would function at sufficiently low power.

Quartz crystals have been in regular use for many years to give an accurate frequency for all radio transmitters, radio receivers and computers. Their accuracy comes from an amazing set of coincidences: Quartz -- which is silicon dioxide like most sand -- is unaffected by most solvents and remains crystalline to hundreds of degrees Fahrenheit.

The property that makes it an electronic miracle is the fact that, when compressed or bent, it generates a charge or voltage on its surface. This is a fairly common phenomenon called the Piezoelectric effect. In the same way, if a voltage is applied, quartz will bend or change its shape very slightly. If a bell were shaped by grinding a single crystal of quartz, it would ring for minutes after being tapped.

Almost no energy is lost in the material. A quartz bell -- if shaped in the right direction to the crystalline axis -- will have an oscillating voltage on its surface, and the rate of oscillation is unaffected by temperature. If the surface voltage on the crystal is picked off with plated electrodes and amplified by a transistor or integrated circuit, it can be re-applied to the bell to keep it ringing.

A quartz bell could be made, but it is not the best shape because too much energy is coupled to the air. The best shapes are a straight bar or a disk. A bar has the advantage of keeping the same frequency provided the ratio of length to width remains the same. A quartz bar can be tiny and oscillate at a relatively low frequency -- 32 kilohertz KHz is usually chosen for watches not only for size, but also because the circuits that divide down from the crystal frequency to the few pulses per second for the display need more power for higher frequencies.

Power was a big problem for early watches, and the Swiss spent millions trying to bring forward integrated-circuit technology to divide down from the 1 to 2 MHz the more stable disk crystals generate. Modern quartz watches now use a low-frequency bar or tuning-fork-shaped crystal. Often, these crystals are made from thin sheets of quartz plated like an integrated circuit and etched chemically to shape. The major difference between good and indifferent time keeping is the initial frequency accuracy and the precision of the angle of cut of the quartz sheet with respect to the crystalline axis.

The amount of contamination that is allowed to get through the encapsulation to the crystal surface inside the watch can also affect the accuracy. The electronics of the watch initially amplifies noise at the crystal frequency. This builds or regenerates into oscillation -- it starts the crystal ringing.

The output of the watch crystal oscillator is then converted to pulses suitable for the digital circuits. These divide the crystal's frequency down and then translate it into the proper format for the display.