How Do Watches Run?

There may be as many different types, models and manufacturers of watches as there are people to wear them.  Some watches must be wound manually, others wind themselves in response to movement from the wearer and some are powered by button cell batteries.  The most common type of watch, and often the least expensive, is the quartz watch.

Quartz Watches

Quartz watches are the most commonly purchased of watch types.  Analogue describes the watch face, which has hands and numbers that indicate the time.  Digital quartz watches have a display with changing numbers.

Quartz watches contain a circuit that counts the seconds as they pass.  The circuit is connected to tiny gears.  The gears are attached to a gear train that moves the hands around the face of the watch.  The concept of the gear train is similar to that of the drive train in an automobile.

In order to move the gears, the battery sends an electric current through the circuit and the quartz crystal.  The current causes the crystal to vibrate or oscillate.  The quartz used in watches will always vibrate at the same rate: 32,768 per second.  The circuit counts the number of vibrations and generates an electric pulse after each 32,768th oscillation or once each second.  The pulse gives the watch's motor the power it needs to turn the gears, moving the watch's hands.

In the case of a digital quartz watch, the process is much the same.  However the pulse powers the display, changing the digital numbers, rather than moving the hands.

Wind Up Watches

Originally watches were powered by the owner who turned the knob to wind the watch and make it run.  Wind-up watches are still manufactured and still very popular.  High end watches contain jeweled movements and other accessories.  Regardless, the basic mechanical operation is the same and is described here at its fundamental level.

To begin the process the winding stem must be turned.  Turning the stem compresses the mainspring.  The escapement is the portion of the watch motor that controls the speed at which the mainspring unwinds.  As it unwinds, it moves the various gears and wheels that are attached to the gear train.  As the gear train turns, the hands move around the face.  Wind up watches are always analogue.  Each gear is responsible for a different measure of time and a different watch hand.  Therefore they are connected to different components and move at a different rate.