Which component of a watch supplies power to the movement?

The mainspring is the component of a watch that supplies power to the movement. It is a coiled spring that, when wound, stores potential energy. As the mainspring unwinds, it releases this energy, which drives the movement of the gears and ultimately powers the watch. This process is vital for the functioning of both mechanical and automatic watches, as it directly affects how the timekeeping mechanism operates.

The balance wheel, while essential for regulating the movement of the watch, does not provide power; instead, it oscillates to maintain accuracy. The escapement works to control the release of energy from the mainspring, releasing it in a controlled manner to keep the gears moving at a consistent rate. Meanwhile, the crown is the part of the watch that is used to set the time and, in some watches, to wind the mainspring, but it does not supply power itself. Understanding the role of the mainspring is key in grasping how mechanical watches function.