First Swiss Electro-Mechanical Watch, the 1960 Landeron 4750
Before quartz battery powered watches nearly destroyed mechanical innovation in the seventies, there existed a brief period of transition, an electro-mechanical era. The first battery-powered watches were, of course, the famed Hamilton Electric series of the late fifties and early sixties. There were other technological hybrids including the first electronic diode watch by the French company Lip and the transistorized Bulova Accutron with their tuning fork mechanisms.
This is the 1960 Landeron 4750, the first Swiss-electric movement. As you can see by the component diagram below, these were not simple watches like the inanimate battery powered Quartz of today. I'm featuring one of the more unique versions of this watch, the 'Montre à Couilles', as detailed in Pieter Doensen's book, built as a demonstration model with two externally cased battery compartments.