Automatic watch

An automatic or self-winding watch is a mechanical watch in which the mainspring is wound automatically as a result of natural motion of the wearer's arm, to provide energy to run the watch, making manual winding unnecessary. A mechanical watch which is neither self-winding nor electrically driven is called a manual watch.

After the introduction of quartz watches, electronic automatic quartz watches powered by arm movement were developed by Seiko. Typically a weighted rotor turns a tiny electrical generator, charging a rechargeable battery or low-leakage capacitor, which powers the quartz movement. This automatic quartz arrangement provides the accuracy of a quartz movement without the need for routine battery replacement. An alternative power source with functional similar results is a photoelectric cell ("solar watch").

A peek of the inner mechanism of a self-winding watch. (From: How Does An Automatic Watch Work? - Patek Philippe 5180 ; Watchfinder & Co)

Automatic quartz is a collective term describing watch movements that combine a self-winding rotor mechanism (as used in automatic mechanical watches) to generate electricity with a piezoelectric quartz crystal as its timing element. Such movements aim to provide the advantages of quartz without the environmental impact of batteries.

A rotating pendulum inside the case is attached to a relatively large gear which meshes with a very small pinion. As the wearer moves, the pendulum turns and spins the pinion at a very high speed - up to 100,000 rpm. This is coupled to a miniature electrical generator which charges a storage device which is a capacitor(s) or a rechargeable battery. A typical full charge will last between two weeks and six months.

Related Links:

* Automatic Watch

* Mechanical Watch

* Automatic Quartz

* The Watch Spot

* Mechanical mechanism watch 2824 rolex [ETA-2824]