Porównanie zegarków automatycznych

Inside sits a mechanical movement with a mainspring, gear train, escapement and balance wheel. A semicircular rotor turns with every movement of your wrist and winds the spring. The stored energy is called the power reserve – around 40 hours for most movements, and 70 to 80 hours for modern calibres. If you take the watch off for longer, it stops and has to be reset. Hand-wound watches work in a similar way but have no rotor: you wind them regularly via the crown.

Many affordable automatic watches run on the Seiko calibre NH35 (or the NH36 with a day display). It has 24 jewels, beats at 21,600 vibrations per hour, offers around 41 hours of power reserve, hacking seconds and hand-winding. The manufacturer's accuracy rating is roughly −20 to +40 seconds per day – in practice many examples run better. Equally widespread are Miyota movements from Citizen (e.g. the 8215 or 9015) and Chinese calibres from Seagull. In more expensive watches you'll find Swiss movements such as the ETA 2824-2 or Sellita SW200.

A display caseback shows the movement – nice to look at, but it says nothing about quality. Skeleton dials are a design feature; in very cheap watches, the movement behind them is often simply finished.

Automatic watches don't like strong magnetic fields – don't put them directly on speakers, tablets with magnetic covers or wireless chargers. Hard knocks, for example when playing tennis or hammering, can strain the balance wheel. If you wear several automatic watches in rotation, you can use a watch winder, but it isn't necessary. Also check the water resistance: many automatic watches with a display caseback offer 3 to 5 bar; for swimming, 10 bar and a screw-down crown are the safe choice.