Automatic quartz is an umbrella name for watch movements in which a self-winding rotor produces the power and a quartz crystal keeps time. The electricity comes from the wearer’s arm movement, not from a battery. Seiko developed the idea, and ETA and Citizen also made their own versions.
How does automatic quartz work?
Inside the case, a swinging weight turns a large gear. That gear drives a tiny pinion. When the wearer moves, the pinion can spin at up to 100,000 revolutions per minute. In Seiko’s design, this gearing speeds up the rotor’s turns to produce an electric current. The current charges a capacitor, and the capacitor runs the timekeeping circuit. The quartz crystal then keeps time, as in any quartz watch. In short, the rotor takes the place of the battery, while the timekeeping stays electronic.
Where it comes from
Seiko began developing the technique in 1983. It first showed it at the 1986 Basel trade fair under the provisional name AGM. The first watch of this type went on sale in Germany in January 1988. The Seiko Museum dates it to 1988 and calls it the first quartz wristwatch to run on electricity made by arm movement rather than on a battery. Seiko’s early movements were known as AGS, short for Automatic Generating System. Its first calibre of this kind was the 7M22.
Who else made automatic quartz movements?
Seiko was not the only maker. ETA, a Swatch Group company, made seven automatic quartz movements of its own. It sold them under the name Autoquartz. Citizen also made an autoquartz watch, the Eco-Drive Duo. It came out in December 1998. That was almost eleven years after the first watch of this type went on sale in Germany.
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