Variator
A variator is a device that can change its parameters, or can change parameters of other devices. Often a variator is a mechanical power transmission device that can change its gear ratio continuously (rather than in steps). Examples
 Beier variable-ratio gear
 Continuously variable transmission
 Evans friction cone
 NuVinci continuously variable transmission
 Variator (variable valve timing)
 Variomatic
 VANOS

See also
 Epicyclic gearing

 
Mechanical power control