Bulova’s "Accutron" tuning fork watches, were first sold in October 1960, using a 360 Hz tuning fork replaced the balance wheel as the regulating element. Invented by Max Hetzel, born in Basel, Switzerland, and joined the Bulova Watch Company in 1948.
The tuning fork was powered by a single transistor electronic oscillator circuit. The Accutron had a high-pitched hum which came from the vibrating tuning fork. The second's hand moved smoothly around the dial at a constant rate (not jumping) due to the high frequency of the vibration of the tuning fork which drove the mechanical gear train.
