This article aims to give a brief overview of the variety of different watch movements available and you will be likely to encounter.You may find more details about this at mvmt reviews.
A quartz watch is a watch that uses an electronic pendulum that is regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz timepieces are at least an order of magnitude more accurate than good mechanical clocks. Generally, some form of digital logic counts the cycles of this signal and provides a numeric time display, usually in units of hours, minutes, and seconds. Quartz timekeepers are the world’s most widely used timekeeping technology, used in most clocks and watches, as well as computers and other appliances that keep time.
An automatic or self-winding watch is a mechanical watch, whose mainspring is wound automatically by the natural motion of the wearer’s arm, providing energy to keep the watch active, making it unnecessary to manually wind the watch.
These are powered by an internal spiral spring called a mainspring which turns the gears that move the hands. The spring loses energy as the watch runs, so in a manual watch movement the spring must be daily wound by the owner turning a small knob on the case to provide energy to run the watch, otherwise the watch runs down and stops.
A self-winding watch movement is similar to a manual movement with the addition of a mechanism powered by an eccentric weight which winds the mainspring. The watch contains a semicircular rotor, an eccentric weight that turns on a pivot, within the watch case. The normal movements of the user’s arm and wrist cause the rotor to pivot back-and-forth on its staff, which is attached to a ratcheted winding mechanism. The motion of the wearer’s arm is thereby translated into the circular motion of the rotor that, through a series of reverser and reducing gears, eventually winds the mainspring. Modern self-winding mechanisms have two ratchets and wind the mainspring during both clockwise and counterclockwise rotor motions.
Chronometers use a form of Quartz movement and are designed as time standards. They often include a mechanism to keep the crystal at a constant temperature to avoid any variance in density or otherwise interrupt the precise running of the timepiece. Some self-rate and include crystal farms, so that the clock can take the average of a set of time measurements to ensure that they are running on time.
The Eco-Drive concept introduced several major technical refinements over previous solar powered watches. The combination of these refinements for the first time gave watch designers the opportunity to design light powered watches without the need to incorporate conspicuous solar cells on the watch dial.
Most Eco-Drive type watches are equipped with a special titanium lithium ion secondary battery that is charged by an amorphous silicon solar cell located behind the dial. Light passes through the covering crystal and dial before it reaches the solar cell. Should insufficient light hit the solar cell after time the watch will go into hibernation and a quartz movement (see above) will keep track of time. During this time the hands will stop but will return to normal once light hits the cell again.