Why/how does a digital clock slow down?


I have a digital clock in the shower that will slowly lose about 5 minutes over the course of a month, no matter how fresh the batteries are. I’m used to analog clocks slowing down, or digital clocks’ LCD displays fading if they’re malfunctioning or losing power.

In: Technology

Electronic clocks work on a quartz crystal which oscillates, which adjusts its electrical properties as it does so.

That oscillation is not accurate, two pieces of such quartz don’t oscillate at the same frequency.

Over time, that oscillation is “close enough” but never actually accurate.

The oscillation is affected by temperature, humidity, pressure, all kinds of things.

Simply put: A quartz clock will never be accurate over any significant period of time.

Yet it’s always more accurate than any clockwork mechanism (which is why people loved “quartz watches” when they first came out).

But it’s nowhere near accurate enough to maintain time over the course of a year.

About the only thing you’ll ever touch/afford that is more accurate is a radio-controlled watch (MSF in the EU, some equivalent in the US), or an NTP-synced clock on your computer (Windows automatically syncs your computer to an NTP source… as does your smartphone).