Hall effect discovery process
The Hall effect is a kind of electromagnetic effect. This phenomenon was discovered by American physicist Hall (E.H. Hall, 1855-1938) in 1879 when studying the conductive mechanism of metals.  When the current is perpendicular to the external magnetic field through the semiconductor, the carriers are deflected, and an additional electric field is generated perpendicular to the direction of the current and the magnetic field, thereby generating a potential difference across the semiconductor. This phenomenon is the Hall effect. The potential difference is also referred to as the Hall potential difference. The Hall effect is judged using the left-hand rule.
The Hall effect was discovered by the physicist Hall in 1879. It defines the relationship between the magnetic field and the induced voltage, which is completely different from traditional electromagnetic induction. When a current passes through a conductor in a magnetic field, the magnetic field produces a force perpendicular to the direction of electron motion for the electrons in the conductor, creating a potential difference in both directions perpendicular to the conductor and the magnetic line of inductance.
Although this effect has been known and understood many years ago, Hall-based sensors are not practical until significant advances in material processing, until high-intensity constant magnets and signal conditioning circuits operating at small voltage outputs appear. Depending on the design and configuration, Hall effect sensors can be used as on/off sensors or linear sensors in power systems.