intro to the hall effect.pdf

An Introduction to the Hall Effect 3
The Theory of
the Hall Effect
The action of the Hall effect in Equipotential Lines Hall Plate Figure 1
a semiconducting medium is Explanation of the Hall effect
adequately explained by This equation ignores many low
quantum physics. However, in spite level effects but will suffice for
of its ings, the classical the depth of this discussion.
approach is chosen here for its
Equipotential Lines With No ic Field Note:
brevity. All B fields in the article refer to the
A particle with charge Q, component of the external B field
velocity, ¯V and moving within a that is normal to the surface of
¯ the Hall plate. A more general
ic field, B, will experience equation for Hall voltage is VH =
the Lorentz force, F=Q(V¯ xB).¯ The yIB sinØ), where Ø is the angle is
between B and the normal to the
force direction is mutually Equipotential Lines In A ic Field Hall plate surface.
perpendicular to the directions
of the particle velocity and the
ic field. If a long, flat
current-carrying conductor is (electrons)
placed in a ic field, the
moving charges will experience a
net force mutually perpendicular to
the direction of the current flow
(longitudinal conductor axis) and the What Is A Hall Sensor?
ic field. Under the influence A Hall sensor is a four-terminal, solid-state device capable of producing an
of this force, the electrons will “pile
output voltage VH, proportional to the product of the input current, lc,the
up” on one edge of the conductor, ic flux density, B, and the sine of the angle betweeen B and the plane
and positive charges will gather on of the Hall sensor.
the other edge. An un-even lateral A reversal in the direction of either the ic field or the control
charge distribution results and current will result in a polarity change of VH. A reversal in the direction of both
¯
gives rise to an electric field, E, will keep the polarity the same. By holding the control current constant, the
¯ ¯