How Does a Clock Know the Time?
A tiny quartz crystal shakes 32,768 times a second. A chip counts every shake, and a magnet turns the count into a tick.
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How a Quartz Wall Clock Keeps Time
A battery wall clock keeps time with a tiny quartz tuning fork that vibrates 32,768 times a second while a chip drives it with a small voltage. The chip halves that rate 15 times to get exactly one pulse per second. Each pulse flips a small magnet half a turn in a stepping motor, and gears turn those steps into the movement of the second, minute and hour hands.
Transcript
Tick. Tick. Your wall clock never misses a second. How does it know? Let's cut it open. Behind the face sits a tiny piece of quartz. Give it a little voltage, and it shakes. 32,768 times a second. A chip counts every shake. Each time it reaches 32,768, it sends one pulse to a coil. The coil flips a little magnet half a turn. That's the tick you hear. The magnet drives the gears. Sixty ticks, and the second hand goes round once. The minute hand turns sixty times slower. The hour hand, twelve times slower again. So every tick you hear starts as a crystal, shaking. Tick.
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