What Is Hall Angle Sensor and How Does It Work

Introduction

A Hall angle sensor is a transducer that varies its voltage in response to the magnetic field. They are used in field of proximity switching, positioning, speed detection, etc. The working principle and key applications of Hall angle sensors are detailed below:

Working Principle

A Hall angle sensor contains an indium compound semiconductor like indium antimonide. It is mounted on an aluminum backing plate and cased in the probe head. The Hall sensor is held such that the magnetic field lines pass through the sensor of the probe at right angles. The sensor then gives the reading of the magnitude of magnetic flux density. The crystal is placed in a magnetic field and a current is passed through it. This creates a Hall effect voltage across it. The sensor works like an analog transducer that returns a voltage. If the magnetic field is known, its distance from the Hall plate can be determined. You can use a group of sensors to know the relative position of the magnet.

Applications

Some of the most common applications of Hall angle sensors are discussed below:

Position Sensing

Position sensing is the most common application of Hall angle sensors. They are used in the brushless DC motor to determine the position of the rotor and to switch the transistors in the correct sequence.

DC Current Transformers

These sensors are also used for the contactless measurement of DC in current transformers. The Hall sensor is mounted in the gap in the magnetic core around the current conductor. This helps in determining the DC magnetic flux and DC in the conductor.

Automotive Fuel Level Indicator

Hall angle sensors are used in automotive fuel level indicator. The principle behind its operation is position sensing of a floating element. It is done by either using a vertical float magnet or a rotating level sensor. In a vertical float system, a permanent magnet is mounted on the surface of the floating object. The conductor is fixed on the top of the tank and aligns with the magnet. When the fuel level increases, a rising magnetic field is applied which causes a higher voltage. As the fuel level falls, the voltage also reduces, causing the indicator to drop.

In a rotating level sensor model, a diametrically magnetized ring rotates about a linear Hall sensor. In such a model, the Hall sensor only measures the vertical component of the field.