Timepiece driven by a source of mechanical energy and regulated by an electric circuit

摘要

The hands of the timepiece are connected to a barrel spring which also drives the rotor of a generator at a speed greater than a desired speed Vc. The electric energy supplied by the generator energizes a slaving circuit that includes a transistor which short-circuits the coil of the generator and thus brakes the rotor down to a speed less than the desired speed Vc when a comparator indicates that this rotor is ahead with respect to its theoretical angular position. A limiting circuit limits the duration of the braking action of the rotor to a fraction of the period of the a.c. voltage supplied by the generator. This arrangement ensures that the slaving circuit is adequately energized even if the rotor is substantially ahead.