To those who are not familiar with watch movements, here is a quick, layman’s outline of what is behind the face of your watch.
There are 3 major types of movements in the world. A movement is simply the means by which a watch or clock tells time. Each movement usually has one or more derivatives, generally based on where the movement gets its’ energy from.
Quartz Analog Watch:
By far the most popular movement. The time is derived by the oscillation of a quartz crystal, hence, the name. This very precise oscillation is monitored by a small integrated circuit. The integrated circuit then drives tiny motor once a second which drives the gear train of your watch. The gear train of the watch drives the hands which show you the time.
The power to drive the quartz crystal, circuitry and motor is electrical. This power is derived in the following ways:
- A disposable battery. It can last anywhere from 3 to 11 years, depending on the watch.
- Kinetic or Autoquartz. A small rotor (an uneven weight) spins every time the wearer moves his or her wrist. This spins a tiny generator which charges a power storage unit, usually a rechargeable battery.
- Ecodrive or Solar. This uses light falling on a small solar panel to recharge the battery. The panel is integrated into the face of the watch and is often invisible.
- Thermic or heat powered. This is very rare watch that uses body heat to generate electricity which charges the battery.
Seiko created the first production quartz, the Astron in 1969. They also developed the Kinetic and Thermic watches as well. As a side note, Seiko is actually quite older than Rolex.
Quartz Digital Watch:
This watch also uses a quartz crystal to determine how much time has passed. Movement is really not the proper term for this kind of watch since nothing really moves. A small integrated circuit drives a Liquid Crystal (LCD) or light Emitting Diode (LED) display. This kind of watch is more tiny computer that happens to tell time.
They were very popular in the 1980’s and early 90’s. They are still desirable when extreme physical shocks are involved, since there are no moving parts. However, they have almost no collectors value and are almost impossible to repair.
All digital quartz watches that I know of use a disposable battery.
This kinds of movement has a long history behind it, 400 years or so. A mechanical watch uses the energy stored in a spiral spring to drive a gear train. The speed the gear train moves is determined by a balance wheel. This is a precisely balanced oscillating weight that allows the gear train to advance at a fixed rate. It has no electrical components, has no battery, and can last longer than the original owner.
The energy in the mainspring can be derived in two ways:
- Hand winding the watch. The crown on the watch is turned to wind the main spring. This must be done at least every two days or the watch will wind down and stop.
- Automatic winding watch. This uses the motions of the wearer’s wrist to spin a rotor to wind the mainspring. If the watch is worn every day, the watch is kept wound. Some automatics can also be hand wound when needed.
Although they are the least accurate, mechanical movements are much more popular with collectors. Their durability and the craftsmanship behind them offset the inherent inaccuracies.