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by zemnmez 525 days ago
I apologise for my "but, actually...":

Analogue clocks like the face of big ben are not like digital displays, and whether they "show seconds" in the context of the meaning of this article is not, like digital displays, down to whether there is a dedicated hand.

Unlike digital displays, the largest denomination hand on an analogue clock display contains all of the information that the smaller hands do (depending on the movement in some cases).

The easiest way to realise this is to imagine a clock without the minute hand. Can you tell when it's half-past the hour? You can. The hour hand is half way between the two hours.

Again, it depends on the movement, but it is not out of the question that your minute hand is moving once every second, and not every minute. It is down to the number of beats per unit time for an analogue display as to what the minimum display resolution is (regardless of if the movement is analogue or digital itself).

5 comments

Unlike digital displays, the largest denomination hand on an analogue clock display contains all of the information that the smaller hands do (depending on the movement in some cases).

You would be surprised. When I was a kid, I sometimes used to stare at the clocks with an analog face at the train station while waiting for the train to school to arrive.

Interestingly enough the seconds hand would go slightly faster than actual seconds and at the 60 seconds the seconds hand would get stuck for a moment as if it was pushing the minutes hand and then the minutes hand would flip to the next minute.

Found a video here:

https://www.youtube.com/watch?v=ruGggPYQqHI

The description describes how they work, which seems like a mixture of digital and analog (due to the use of both cogs and relays + propagation of pulses from central to local clocks), translated:

- The seconds hand makes a revolution of 57-58 seconds and is then stuck for 2-3 seconds.

- The seconds hand is driven using 230V.

- The minutes hand get a 12V or 24V pulse once every 60 seconds. The polarity has to swap every 60 seconds. The swapping of the polarity can be done using a relay or specially-made components.

- The hours hand is driven by the minutes hand using cogs.

Edit: more information and references here: https://en.wikipedia.org/wiki/Swiss_railway_clock#Technology

The key to this mechanism is that the stepping of the minute hand is what unlocks the second hand. Pretty clever low-tech way to keep a LOT of clocks in really close sync.

Dutch train stations used to have these too, I loved to watch them in action while waiting for a train.

On a wristwatch it's also easy - and probable - to set a minutes hand out-of-sync with the seconds, so they don't both line up at 12 at the hour.
Thanks for the video, what a silly design, especially given the Swiss reputation when it comes to clocks...
If you think of the design goals (synchronizing clocks across the train network) and the technology available at the time, the design is actually pretty clever. Knowing the exact second is not important - if the second hand actually completes a whole cycle in only 58 seconds, this is still good enough to be able to see how much of the minute has passed. Having the exact same minute on all clocks is much more important than that - especially since train departure times are usually "on the minute".
What technology wasn't invented by the time this clock was created??? And the design is bad, nothing clever about it, clocks can move their minutes hand to give the necessary indication
What technology wasn't available in 1944 (https://en.wikipedia.org/wiki/Swiss_railway_clock#Technology) compared to today? Quite a lot...
So name a single time tech and explain how the lack of it didn’t prevent other train station operators having clocks without jumping hands operating even before 1944? (not sure, but think that the minute timetable resolution was pretty universal)
>The easiest way to realise this is to imagine a clock without the minute hand.

No need to imagine it, it's been invented many years ago and it's called a perigraph. Meistersinger makes one of the nicest I've seen: https://www.relogios.pt/meistersinger-perigraph-relogio-auto...

> it depends on the movement, but it is not out of the question that your minute hand is moving once every second, and not every minute.

I think the only place where I've seen the minute hand move by the minute has been on TV, in those climactic moments where the camera zooms in on the clock and strikes a certain time. Maybe it's a trope, for emotional tension, like mines that don't explode until you step off.

> The easiest way to realise this is to imagine a clock without the minute hand. Can you tell when it's half-past the hour? You can. The hour hand is half way between the two hours.

Can I? Many analog clocks actually "tick" the second and minute hand. I've even seen some that tick the hour hand.

You literally just defined the difference between digital (binary) and analog (gradation).

A digital clock is 1:01 or 1:02. An analog clock is some tick of some range (depending on the resolution, as you abstracted), at all times.

I think a slightly better term is "discrete" vs "continuous". Some analog clocks are discrete, some are continuous. Some digital clocks operate on a resolution so fine that they appear to move continuously. It's quite lovely to find those that invert your expectations when out in the real world.
It's a bit more than that:

There are analog clocks where all hands move continuously (like when there's a second hand with no discernable beats). There are analog clocks where all hands move discreetly once per second (60 BPM for all hands). There are analog clocks where the minute hand moves at 1 BPM (quantized to the floor of each minute) while the second hand does something else (perhaps discrete movement at 60 BPM, or perhaps continuous other than a pause at the top of each minute, etc.). And there are digital clocks!

You're correct, thanks for the clarification. I was going more with the colloquial understanding of the two (analog = continuous; digital = discrete) and was trying to touch on the vagueness of no true analog clock with the reference to ticks/resolution.

However, your explanation is definitely much better.