Electromagnetic Testing Chapter 3- Electromagnetic Testing

E. H. Hall accidentally discovered the Hall effect in 1879 while he was
investigating the effect of magnetic forces on current-carrying conductors at
John Hopkins University. At that time, he discovered that strong magnetic
fields skewed the equal potential lines in a conductor, thus producing a
miniature voltage perpendicular to the direction of current flow.With metal
conductors, the voltage levels produced were so low that the phenomenon
remained a laboratory curiosity until practical development of the
semiconductor. In the early 1960s, F. W. Bell, Inc. introduced the first
commercially available, low-cost, bulk indium arsenide Hall generators. In
1968, Micro Switch revolutionized the keyboard industry with their
introduction of the first solid-state keyboard using Hall effect devices that
incorporated the use of a Hall generator and its associated electronic circuit
on a single integrated circuit chip. Today Hall effect devices are used in a
host of products too numerous to mention.
Charlie Chong/ Fion Zhang