How do mechanical (automatic) watches keep time exactly when springs exert different amounts of force depending on how tightly wound they are?

Question

I know that mechanical watches have a spring that they wind to store energy, and un-winding the spring produces energy for the watch. But a spring produces a lot of force when it’s very tightly wound, and very little when it’s almost completely un-wound. So how does the watch even that out with high precision?

In: 95

Answer 1

the spring just provides the power, the timing is set by a wheel that back and forth, like a pendulum on wall clock.

It always swings at the same rate, and at every tick it gets just the energy needed to do it again from the spring