In watchmaking, there are essentially three different types of movements, also called calibers. And, of late, there are also solar powered watches, but that is a different story. Here, we bring you a brief look at exactly what a watch movement is and how the three most common types differ.
Essentially, the watch movement consists of all the parts that power the watch, track the time, and provide the power for added functions. Some of the most complex mechanical watches with additional functions also have specialized modules built onto the base caliber. But we will stay with the essentials herein. There are two types of calibers that are totally mechanical and do not incorporate batteries: Automatic and Hand Wound.
Hand Wound Mechanical Movements
Essentially a hand-wound — also called manual-wind — is one in which the wearer must manually wind the watch via the crown. By winding the crown, the mainspring inside the watch is coiled tightly via a gear train that leads from crown to spring. As the spring slowly unwinds, it releases its energy, powering the watch. Of course, the system is much more complex than that. Inside the mechanics, a balance wheel and spiral work to keep energy released by the spring consistent and accurate. The key with this type of movement is that one must remember to wind the watch or the energy will deplete and the time indications will need to be manually reset before winding the watch again.
A mechanical watch with an automatic movement (also called a self-winding movement) works in a similar method. However, in this type of movement, a few additional parts come into play. Each caliber in an automatic movement is fitted with a rotor that moves when the wearer moves his or her wrist. That movement automatically powers the rotor (sometimes referred to as an oscillating weight), which winds the mainspring. The watch is powered as long as it is being worn, and the power in that watch will last – when taken off and sitting still in a box or on a dresser – for a designated time period. That time period is called “power reserve” and different watches are equipped with varying amounts of power reserve.
A quartz movement is not powered by mechanics, but instead by a battery. Quartz watches were first developed in the late 1960s and early 1970s, and came into true serial production in the late 1970s and early 1980s. Quartz watches use a tiny piece of low-frequency quartz crystal (silicon-dioxide) that is chemically etched into shape in an integrated circuit, and that serves as the oscillator. A nearby battery sends electricity to the quartz crystal through an electronic circuit. The quartz oscillator then vibrates quickly and with precise frequency (32,768 times/second) in response to the electronic charge. The circuit counts the vibrations and generates regular electric pulses of one per second to drive the motor that turns the hands. There is no need to turn the crown or set the watch after the first time. However, in quartz watches, the batteries will die and need to be replaced.