Why do all my clocks run slow?

[greypilgrim]

Hi.
I noticed that all electronic devices in my household that also tell time eventually lag behind, except the ones that get synchronized by radio signal or internet. Most of them are battery-powered, except my alarm clock (which runs slow as well).
Why does none of them run too fast? Deliberate design (why)? Wrong temperature for quartz crystal? Decreasing battery voltage?

Or just a coincidence?

 

[.Scott]

If you have an alarm clock that runs off wall current, it is almost certainly getting it pace from the power company. It will never run significantly fast - but if it becomes unplugged or you lose power now and then, it could appear slow.

Quartz oscillators are generally designed to be isolated from power source voltage fluctuations, but temperature is different issue.

Temperature is another matter. I have looked at a couple of sources and they say the same thing - that crystal-driven clocks are designed for room temperature (20C) or, for wrist watches 25C. Varying above or below that temperature makes the watch less precise - and that's as far as it goes. I found no mention that "less precise" favors either a lower or higher clock rate - but they do say it is the same in both directions (hotter or cooler).

 

[Baluncore]

Why does none of them run too fast?

Each clock has particular characteristics and needs to be discussed in isolation. Maybe you only notice slow clocks because you miss things, rather than get there a little early.

Clocks were once designed to be corrected after a stop by moving the clock hands forwards in time. If you turned the hands backwards, they came undone. To set a clock backwards you had to stop the clock, wait until it was correct, then start it again.

A clock is advanced in many steps. In general, it is easier to miss one step than to take two.

Some clocks were deliberately designed to run fast, then they are held waiting at a defined point, until a master clock pulse arrived, to release their gear train, hence the term "waiting train" clock.


https://waitingtrain.blogspot.com/2008/08/wt-pendulum-hipp-toggle-and-driving.html