Overview
A vibrator is a mechanical device to generate vibrations. The vibration is often generated by an electric motor with an unbalanced mass on its driveshaft.
There are many different types of vibrator. Typically, they are components of larger products such as smartphones, pagers, or video game controllers with a "rumble" feature.
Vibrators as components
When smartphones and pagers vibrate, the vibrating alert is produced by a small component that is built into the phone or pager. Many older, non-electronic buzzers and doorbells contain a component that vibrates for the purpose of producing a sound. Tattoo machines and some types of electric engraving tools contain a mechanism that vibrates a needle or cutting tool. Aircraft stick shakers use a vibrating mechanism attached to the pilots' control yokes to provide a tactile warning of an impending aerodynamic stall.
From Wikipedia (CC BY-SA 4.0).