When a beam of charged particles passes through a magnetic field, forces act on the particles, and the beam is deflected from a straight path. The flow of electrons through a conductor forms a beam of charged carriers. When a conductor is placed in a magnetic field perpendicular to the direction of the electrons, they are deflected from a straight path. As a consequence, one plane of the conductor becomes negatively charged, and the opposite side becomes positively charged. The voltage between these planes is called the Hall voltage.