Modern watches are usually controlled electronically, rather than mechanically. These watches derive their accurate timing from the use of a quartz crystal. It was found that when a voltage was passed across a crystal of quartz it became slightly deformed. As this deformation occurred the quartz crystal maintains a voltage that oscillates at the same rate as the quartz crystal's own natural vibration. The vibration generated has a frequency of 100,000 times per second. These oscilations are counted by a microprocessor chip and then displayed via a display driver microchip on the watches liquid crystal display in seconds, minutes and hours.
These all electronic watches are incredibly accurate, sometimes to within a second a month. The electronic watch is a miracle of modern electronic miniaturisation.
