Magnetostrictive position sensors are non-contact linear position sensors that use the momentary interaction of two magnetic fields to produce a strain pulse that moves along a waveguide. One field is from a magnet that moves along the outside of the waveguide. The other field is from the waveguide itself. Typically, the waveguide wire is enclosed within a protective cover and attached to the device that is being measured. Applying a current pulse generates a sonic wave that travels along the waveguide to a small piece of magnetostrictive material that passes through a coil and is magnetized by a small, permanent magnet. The stress induced by the sonic wave causes a wave of changed permeability in the magnetostrictive material, resulting in a change in its magnetic flux and the production of voltage output from the coil. Electronic circuitry detects the voltage pulse and conditions it into the desired output. Depending on the sensor’s characteristics, measurements can be either absolute or incremental.