The earliest magnetic field detectors allowed navigation
over trackless oceans by sensing the Earth's magnetic
poles. Magnetic field sensing has vastly expanded as
industry has adapted a variety of magnetic sensors to
detect the presence, strength, or direction of magnetic
fields not only from the Earth, but also from permanent
magnets, magnetized soft magnets, vehicle disturbances,
brain wave activity, and fields generated from
electric currents. Magnetic sensors can measure these
properties without physical contact and have become
the eyes of many industrial and navigation control systems.
This paper will describe the current state of several
methods of magnetic sensing and how the sensors
are used—many with integrated functions. Finally, several
applications will be presented for magnetic sensing
in systems.