Magnetic field sensors

,986m MAGNETIC-FIELD SENSORS The physical operation of magnetic sensitive resistors is based on the Gauss- effect, which may be sum- marized as follows: a magnetic field with lines of force perpendicular to a current carrying con- ductor forces charge car- riers to travel along the surface of that conduc- tor; the magnetic field "pushes" the current into a thin layer, which results in a diminished cross-sec- tional area for the current to pass along, or, in other words, an increased resis- tivity of the conductive material. Figure 1 il- lustrates this effect which has been known for quite some time, but has re- Fig. 1 The magnet pushes the electric current out of the area with maximum magnetic field strength. Fig 2 A sufficiently high total resistance can only be obtained by means of a long conductor path. Fig. 3 Gold stripes have been applied to the re- sistor track, which make it look like a barber"s pole. Fig 4 The four resistive elements in a Wheastone bridge configuration. An...