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How does a quartz watch work?

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Quick answer

A quartz watch works by applying electricity from a battery to a quartz crystal, causing it to vibrate 32,768 times per second. A microchip counts these vibrations and divides them down to one pulse per second, which drives a motor and gears to move the watch hands.

A quartz watch keeps time by counting the vibrations of a tiny quartz crystal. An electric circuit makes the crystal vibrate 32,768 times per second, and a microchip divides that frequency down to one pulse per second to drive the hands.

Step by step

  1. A small battery sends electric current through a quartz crystal.
  2. The crystal vibrates at a steady 32,768 Hz due to the piezoelectric effect.
  3. An integrated circuit counts the vibrations and divides the frequency by 32,768.
  4. The circuit outputs one electrical pulse every second.
  5. Each pulse powers a tiny stepping motor that turns gears.
  6. The gears move the watch hands to display the time.

Key things to understand

  1. A small battery provides electric current to a quartz crystal shaped like a tuning fork.
  2. The crystal vibrates at a precise frequency of 32,768 times per second when electrified.
  3. An integrated circuit counts these vibrations and divides the frequency by 32,768.
  4. The result is one electrical pulse per second, which powers a tiny motor.
  5. The motor turns gears that move the watch hands to show hours, minutes, and seconds.

Labelled diagram

  1. Battery

    Provides electric current to power the circuit and crystal.

  2. Quartz crystal

    Vibrates at 32,768 Hz when electricity is applied.

  3. Integrated circuit

    Counts vibrations and divides frequency down to 1 Hz.

  4. Stepping motor

    Receives one pulse per second and turns a small gear.

  5. Gears and hands

    Transmit motion to move the watch hands.

How a quartz watch keeps time

Real-world examples

  • The Seiko Astron, released in 1969, was the first quartz wristwatch and revolutionized timekeeping.
  • Many affordable watches from brands like Casio and Timex use quartz movements for reliable, low-cost timekeeping.
  • Wall clocks and kitchen timers often use quartz crystals to keep time accurately without needing winding.
  • Quartz oscillators are also used in computers and GPS devices to provide precise timing signals.

Common mistake

✗ Myth: Quartz watches are powered by the movement of your wrist.

✓ Fact: Quartz watches are powered by a battery, not by wrist movement. Automatic watches, which are mechanical, use wrist motion to wind a spring, but quartz watches rely on a battery to energize the crystal.

People also ask

What is a quartz watch?
A quartz watch is a timepiece that uses an electronic oscillator regulated by a quartz crystal to keep time. The crystal vibrates at a precise frequency when electricity is applied, and a circuit counts these vibrations to produce accurate timekeeping. It is the most common type of watch today.
How does a quartz crystal keep time?
A quartz crystal has piezoelectric properties: when electricity is applied, it vibrates at a very stable frequency. In a watch, the crystal is shaped to vibrate at 32,768 Hz. A microchip divides this frequency down to one pulse per second, which drives the watch hands.
Why is quartz used in watches?
Quartz is used because it is cheap, abundant, and vibrates at a very consistent frequency when electrified. It also requires little power, so a small battery can last for years. These properties make quartz watches accurate, affordable, and reliable compared to mechanical watches.
Why do quartz watches use 32,768 Hz?
32,768 is 2^15, a power of two, so a simple digital circuit can repeatedly halve the frequency fifteen times to get exactly 1 Hz. This makes the divider circuit compact and reliable, and the frequency is high enough for accuracy yet low enough to use little power.
How accurate is a quartz watch?
A typical quartz watch gains or loses about 15 seconds per month, though high-quality ones can be within 5 seconds per month. This is far better than mechanical watches, which may drift by several seconds per day. Temperature changes can affect accuracy slightly.
What makes a quartz watch stop working?
The most common cause is a dead battery. Other issues include a broken quartz crystal, a faulty circuit, or mechanical damage to the gears or motor. Moisture or dirt inside the case can also disrupt the electrical contacts.
Do quartz watches need winding?
No, quartz watches are powered by a battery, not by winding. Some are solar-powered, using light to charge a rechargeable cell. Mechanical watches need winding, but quartz watches run continuously until the battery runs out.

Part of the guide: Everyday Machines →