Vibration is a movement that starts from a dead center, goes in one direction, and ends when it returns to the dead-centre. When the movement starts again in the opposite direction it will be the next vibration. One oscillation corresponds to two vibrations.

In watchmaking it is thus on the resonator that one counts the number of vibration in a defined time or the degree of angle of the vibration. Nowadays, the resonators are for a mechanical watch a balance, for an electronic watch a quartz or for a wall clock a pendulum.

The number of vibrations in a defined time corresponds to a frequency. The most common unit of frequency related to the vibration is the vibrations/hour. A traditional pocket watch generally has a frequency of 18’000 vibrations per hour. For a good number of escapements, except for the detent escapement, one beat corresponds to a jump in the seconds hand. Thus 18’000 vibrations per hour corresponds to 5 jumps per second on the second hand.

The degree of angle of a vibration is also measured to define the amplitude, another important measurement of a timepiece. If this measurement is too low it often means that the oils are dry and the timepiece needs an overhaul.