Portable timepiece designed to be worn on the wrist or carried in the pocket. The first watches appeared shortly after 1500, when the mainspring (see spring) was invented as a replacement for weights in driving clocks. The progressive miniaturization of electronic components in recent decades has made possible the development of all-electronic watches, in which the necessary transistors, resistors, capacitors, and other elements are all on one or several miniature integrated circuits, or chips. Such circuitry enables them to perform several timekeeping functions and also makes possible digital readouts of the time.
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