TABLE OF CONTENTS Chapter written by S. RIPKA and Pavel RIPKA.
The term "magnetic sensor" is broadly used for sensors using principles of magnetism. The main part of this chapter is devoted to magnetic field sensors and electric current sensors; magnetic position sensors are also covered in Chapter 7.
Magnetic sensors are usually contactless and robust and therefore they have reached a dominant position in the industrial and automotive sector. Basic information on magnetic sensors and their applications can be found in [1] and [2], more detailed information on some sensor types can be found in [3 5]. Basics on magnetism and magnetic materials are covered in [6 8].
When a conductor carrying a current is placed in a magnetic field, the voltage distribution within the conductor is modified. The changes depend on the relative orientation of the current, the magnetic field and the measured changes. These effects have been classified into three groups:
Hall effect: the applied magnetic field is along the z-axis perpendicular to the current along the x-axis and the Hall voltage is measured along the y-axis perpendicular to both the current and the magnetic field.
Longitudinal magnetoresistive effect: the magnetic field is applied along the x-axis, parallel to the applied current also along the x-axis. The voltage change is measured along the x-axis. This is effectively a small change in conventional resistance.
Transverse magnetoresistive effect: the magnetic field is applied along the y-axis transverse to the current flow along the x-axis and the voltage changes...
