Inside the quartz watch

We see the word on the dial of a watch but, what is a quartz watch and how does it work?  In this post, I cover the history and science as I delve into these tiny, accurate machines.

A quartz watch uses an electronic oscillator that is regulated by a quartz crystal to keep accurate time. The scientific property ( piezoelectric) that makes quartz useful for watches was discovered by Jacques and Pierre Curie in 1880. In 1927 the first quartz clock was built by Bell Labs. Fast forward to 1969 and we have Seiko creating the first mass production of quartz watches.

The science

Let’s get on to the word piezoelectric which means the ability for a material to generate an electric charge in response to applied stress.  If you apply pressure (squeeze) a quartz crystal it generates a small electric current.  If you pass electricity through quartz it vibrates at a precise frequency.  In layman’s terms, it means quartz will shake an exact number of times per second it electricity is passed through the crystal.

Below I crafted a very simple example covering the basics of the inner workings of a quartz watch.

 

  1. A battery sends an electrical current to a microchip.
  2. The microchip makes a quartz crystal that is cut in the shape of a tuning fork. The quartz is often encased in a metal tube. The quartz vibrates or oscillates 32,768 times per second.
  3. The microchip senses the quartz oscillations and turns the oscillations into systematic electric pulses at a rate of one per second.
  4. The electric pulses from the microchip drive a miniature step motor which converts electrical energy into mechanical power.
  5. The motor turns the gear train
  6. The gear train drives the hands of the watch.

Simple, right?

And now, James May’s entertaining video on quartz timekeeping.