Keeping Time

factual friday

How does a watch actually keep time?

Most wrist watches are quartz watches, which were first developed in the late 1970s.

It turns out, rather handily, when you run electricity through quartz crystal it always vibrates with a precise frequency – 32,768 times/second.

Each watch has a tiny piece of quartz crystal (silicon-dioxide) shaped like a tuning fork inside, and the battery sends electricity to the quartz crystal through an electronic circuit. The circuit counts the vibrations and generates regular electric pulses of one per second. The pulses drive the small motor that spins the watch’s hands giving accurate time measurement (until the battery slows and dies).