The electric watch

An electric watch replaces the mainspring with a battery. In the earlier type the battery drives a balance wheel and hairspring through a coil, so the watch still keeps time mechanically.^1, 2

Elgin and Lip showed electric wristwatches in public on the same day, 19 March 1952, and the Swiss historical dictionary dates Swiss electric models to 1952 too.^{2, 5, 6, 7}

Wikipedia and the NAWCC Bulletin say Hamilton was the first to produce and sell one, the Electric 500, in 1957. The day is given as 3 January in some accounts and 4 January in others.^{2, 5, 8, 9}

The Science Museum in London holds a Hamilton electric watch made in Lancaster, Pennsylvania, in 1957, with its spare battery, and names Richard Arbib as its designer.⁹

Arbib’s triangular Ventura case became Hamilton’s best-known design; Hamilton calls it its most iconic watch.^10, 11

Citizen’s X8 of 1966 was the earliest electronic wristwatch made in Japan, according to Wikipedia and Citizen.^12, 13

The second type did away with the balance. Bulova’s Accutron, sold from the autumn of 1960, used a tuning fork vibrating 360 times a second, kept going by a transistor circuit, to drive the hands.^{3, 8, 14, 15}

Its designer was Max Hetzel, a Swiss engineer who worked on Bulova’s electronic watch from the early 1950s.^{3, 14, 15}

Bulova guaranteed accuracy within a minute a month and says the Accutron was the first tuning-fork electronic watch.^3, 17

More than four million Accutrons had been sold by 1973, and the NAWCC Bulletin puts the total above five million by the end of production in 1977.^3, 15

Accutron movements went into timers for NASA: a flight-qualified backup Bulova timer from the Skylab programme of 1973 and 1974 is in the National Air and Space Museum.¹⁸

Seiko says the Accutron shocked the industry, and that from 1959 it studied balance, tuning-fork and quartz designs before choosing quartz.¹

Quartz overtook both kinds. Hamilton itself moved on to the all-electronic Pulsar, announced in 1970, and quartz watches had overtaken mechanical ones in popularity by about 1978.^{15, 19, 20}