right|thumb|Drawing of a centrifugal "fly-ball" governor. The balls swing out as speed increases, which closes the valve, until a balance is achieved between demand and the proportional gain of the linkage and valve.
right|thumb|Drawing of a centrifugal "fly-ball" governor The balls swing out as speed increases, which closes the valve until a balance is achieved between demand and the proportional gain of the linkage and valve.