Regulating organ

THE RESONATOR

In watchmaking, a resonator refers to any physical system capable of oscillating at a stable and determined frequency, used as the timebase of a timepiece. The most common resonator in mechanical watches is the regulating organ balance-hairspring, whose frequency is set by the inertia of the balance and the elasticity of the hairspring (balance spring). Other technologies employ different resonators: the tuning fork of electromechanical watches from the 1960s-1970s, or the quartz crystal, whose piezoelectric vibration today forms the timebase of the vast majority of watches.

From a physical standpoint, the balance-hairspring can, under certain conditions, be likened to a harmonic resonator: its oscillation frequency remains theoretically independent of amplitude, provided that the restoring torque of the hairspring remains strictly proportional to the balance’s angle of rotation. This harmonic approximation nevertheless remains fragile in practice, as geometric defects, air friction, or imperfections in the hairspring introduce deviations from isochronism that move it away from perfectly harmonic behavior. Whatever its nature, a horological resonator must combine frequency stability, low sensitivity to external disturbances, and ease of maintaining the oscillation over time.