Emilio Villari, an Italian physicist in the 19th century, discovered that if a form of mechanical stress is applied to a ferromagnetic material, a change in the magnetic flux occurs. This could either be torque or force. This phenomenon is commonly known as the magnetoelastic effect, also called the Villari effect. Using this magnetoelastic effect, a magnetoelastic sensor can measure two different forms of stress. The first one is force, this is when stress is applied in a linear manner, which compresses or elongates the sensor element. The second one is torque, this is when stress is applied in a twisting manner. Magnetoelastic sensors are not only capable of measuring torque and force, but can also be used for measuring load, direction, position, angle and speed.