Will lead to changes in the dielectric lattice spacing change of direction of magnetization in the ferromagnetic material, thus making the length and volume of the ferromagnetic material change, namely: the magnetostrictive phenomenon, also known as the Wiedemann effect, the inverse effect of the Victoria Larry effects. But not all ferromagnetic materials have a value of only a few with high magnetostrictive properties of new materials of practical value. 
 Magnetostrictive displacement sensor principle: the use of two different magnetic field intersects the strain pulse signal is detected to calculate the exact location of the magnetic field intersecting point. A magnetic field from the sensor electronics stores electronic components generated by the pulse excitation, the excitation pulse magnetic field generated by the speed of light along the waveguide wire sensor measuring rod with high magnetostrictive material since the electronic warehouse side forward to the end of The permanent magnets are generally installed on the need to detect the position of the moving plate) intersects with a permanent magnetic field (due to magnetostriction phenomenon waveguide wire in the point of intersection of a mechanical strain pulse and the speed of sound from this point by the waveguide wire electronic position-side return, the strain pulse detection circuit to detect the electronic compartment. Therefore, from launching an active pulse to the receiver to a strain pulse time (this time is the speed of sound in the waveguide wire passed here has ignored the initiative wave running time, the actual impact was only 0.0001%) have been known speed of sound (a fixed amount to 3000m / s) and delivery time, this distance is of course determined. When the permanent magnet movement to a new location, re-determine these measurements. Therefore, magnetostrictive displacement sensor with high precision, high response, low hysteresis, high reliability, non-contact, long life, high stability, easy installation, etc., without re-calibration, without regular maintenance, they have been accurate measurement of a wide range of adopted.