Why do the hands on a clock go backwards when the battery is dieing?

Question

why don't they just slow down or stop? why go backwards?

Answer 1

To simplify a lot of variation almost all clock mechanisms, electronic or mechanical, can be thought of as having two parts: your main clock mechanism that wants to move things (like the hands in a mechanical clock) and a simple periodic part that produces a

repeating signal that, on average, has an accurate length (like a pendulum in a mechanical clock or a quartz-crystal based oscillator in an electronic one). The oscillator is compared to the main part of the clock and it slightly retards or speeds it up accordingly.

Now think of wagon wheels in a movie western seemingly moving backward because a periodic "sampling" (the shutter on the movie camera) of an longer term repeating action (the motion of the wheels) results in the spokes being seen slightly before their previously seen position.

It doesn't seem far fetched that an electronic glitch, combined with a weak design (nothing equivalent to a ratchet) could cause that synchronizing mechanism to try to "find" another "solution" to getting the clock to get the "right" answer with each repetition -- i.e., go back one cycle instead of forward one.

Another possibility is that a circuit designed to allow the clock to be moved forward or back in order to set it has gotten activated (that the clock doesn't have that capability doesn't mean that the chip doesn't but that the clocks designers decided to forgo the complication of the extra buttons).

On a deeper level, I have known clocks to stop/lose time when something terrible has happened  .

I hope that isn't the case though Tammie.

Answer 2

Probably to alert you that the battery is dying.

Answer 3

that is a new one on me ,perhaps the hands are loose on the dial and falling back...........tom

Answer 4

I've never seen that happen