What Are Hall-Effect Sensors and How Do They Work?
Rotating gears demand internal sensors to measure the speed, position and direction of rotation. Hall-effect sensors are commonly used magnetic sensors that rely on the relationship between electric potential and magnetic fields to transmit an output signal. Here is a basic overview of this frequently used sensor.
What is the Hall Effect?
The Hall effect describes the diverging motion of electrons as they flow through a conductor in the presence of a magnetic field. Normally, electrons flow in a straight line. However, when a magnetic field is present, the electrons deflect from their natural course and accumulate on one side of the conductor, while positively charged particles accumulate on the other side of the conductor. This phenomenon is called the Hall effect. The result is a conductor with a negatively charged side and a positively charged side, which creates an electrical potential, or voltage, across the conductor. This voltage is measurable, directly proportional to the strength of the magnetic field and produces an analog output.
How Are Hall-Effect Sensors Used?
The induced voltage produced by these sensors is quite small, so an amplifier is needed to transmit a readable analog signal, which indicates the speed of the rotating component. The output signal can also be converted to a digital signal in order to create an on-off functionality.
There are variations in the design that expand the sensor’s capabilities. For example, speed and direction sensors utilize two separate sensing devices and detect which sensor the gear passes first to determine rotational direction. Also, angular position sensors detect the angle of the magnetic field to determine the position of the gear, and proximity sensors determine whether a gear is within a defined range of the sensor.
Overall, Hall-effect sensors are reliable devices that shed light on the internal status of rotating equipment. If you are not sure which sensors will work best for your equipment, contact Sensor Solutions for insight and recommendations.