A mechanical watch is an oscillator driven by energy stored in a mainspring. The oscillations are counted by a gear train and displayed on a conventional watch face. How are the oscillations sensed and how is the energy lost to friction replaced? In this lecture Professor Sussman explains this mechanism and relates it to an electrical circuit that is understandable in terms of material taught in MIT’s elementary circuits subject.

At this lecture, a camera provides a close up of the inner workings of a watch. Professor Sussman who is also a life member of the American Watchmakers-Clockmakers Institute concludes,” most good watchmakers spend a considerable amount of their time on their knees chasing down the parts they dropped.”