Quartz watches became popular in the 1970s. At that time these watches had LED displays and cost as much as $500. However, there have been dramatic changes in the appearance, prices and functions of quartz watches ever since the first quartz watch was produced in 1969. That watch was the Seiko 35 SQ Astron.
Today, a quartz watch either has an LCD display or a traditional mechanical movement with hour and minute hands. There has been a very big fall in the price of these watches. You may very well find a quartz watch being given away for free, as a gift with a bag of cereals.
A low-frequency bar or tuning-fork-shaped crystal is used by modern quartz watches. These crystals are often made from thin sheets of quartz. The quartz sheets are plated like an integrated circuit board and are chemically etched to shape.
The level of accuracy of a quartz watch depends on the initial frequency accuracy and the precision of the angle of cut of the quartz sheet with respect to the crystalline axis. The accuracy also depends on the amount of contamination that is allowed to get through the encapsulation to the crystal surface inside the watch.
The electronics in a quartz watch initially amplify noise at the crystal frequency. This noise builds up or regenerates into oscillation and the crystal starts ringing. The output of the crystal oscillator of the quartz watch is then converted into pulses that are suitable for the digital circuits.
These digital circuits divide the crystal’s frequency and translate it into the proper format for display. For watches with hands, one-second pulses are created by the dividers that drive a tiny electric motor. This electric motor is connected to standard gears that drive the hands.
The quartz watches have several different types of power sources. They use battery power, solar power, kinetic power, as well as some other less common power sources. The most common source of power that is used by these watches is the battery. There are many types of batteries, though the most common types are silver oxide and lithium.
Solar powered watches use the available light. Some of these watches work on kinetic power. They use the motion of the wearer’s arm to turn a rotating weight. The weight turns a generator that provides the watch with power.
A source of power that is not used much is the difference in temperature between the wearer’s arm and the environment. This is the method used by the Citizen Eco Drive Thermo.