Introduction
Hall-effect technology was first discovered in 1879. It was discovered by a physicist who was trying to prove the theory of electron flow (Ramsden 12). The physicist, Dr. Edwin Hall, discovered that a magnetic field affected the flow of current in a gold rectangle that was placed perpendicular to the magnetic field. This discovery gave rise to the advent of hall-effect sensing technology. Hall-effect sensors are devices that are magnetic and are used either to measure magnetic fields or as magnetic switches. This technology is often employed in speed detection, current sensing, positioning, and proximity switching. Hall-effect sensors are designed using basic engineering principles and are used in various applications.
Design
Basic hall-effect sensors operate as magnetic field sensors. For them to be usable in various applications, they require signal conditioning. This conditioning includes an amplifying stage and some temperature compensation. If the voltage used is uneven, then there is a need for voltage regulation.
A basic hall-effect sensor consists of a regulator, hall element, a differential amplifier, and voltage input. This type of sensor is an analog device and it produces a voltage equaling its magnetic field. The magnetic field that is produced in this sensor can be either positive or negative. This means that the amplifier records both plus or minus power supplies. Hall-effect sensors are available in a variety of voltage ranges. There are 4.5 to 12, 4.5 to 10.5, and 6.6 to 12.6 VDC sensors. The transfer function of these sensors can be expressed through an equation or a graph. The transfer function value in this case is determined by null-effect, sensitivity, and span.
Digital output sensors on the other hand consist of a regulator, amplifier, Schmitt trigger, and a regulator. Its transfer function incorporates hysteresis and current sinking. Digital sensors can use regulated or unregulated power supplies. Their output depends on operation point, differential, and release point.
Applications
Hall-effect sensors are applied in various devices and mechanisms. The choice of application is primarily based on the operating and release characteristics of the sensor. Some of these applications include vane-operated sensors, gear tooth sensors, current sensors, and magnetically operated switches.
Vane-operated power sensors use both a magnet and a digital hall-effect sensor. These are all placed in a non-magnetic material. There is a gap left for a vane to pass through. This type of sensor is designed to detect the presence or absence of this vane. Any obstruction to this vane activates the sensor and it goes on. When the vane is present again, the sensor will go off. This mechanism also works in reverse when detecting the presence of a vane.
The other common application of hall-effect sensor technology is in gear-tooth sensors. This sensor is designed to sense the movements of metal targets. The gear tooth concentrates magnetic influx into the sensor as it passes through a field. This prompts the sensor to detect this change in influx hence switching it on.
Linear current sensors are made using silicon steel and hall-effect sensors (Kato 1912). These are put together in plastic housing. These sensors are designed to monitor the amount of magnetic flow a current produces as opposed to measuring the actual current flow. These field changes are monitored in the form of waves. This measurement helps determine when there is saturated voltage hence cutting it off.
Conclusion
Hall-effect sensor technology has pioneered many other similar technologies. However, its basic designs and operations are still used in various engineering designs and principles. This technology may still be improved in the future.
Works Cited
Kato, L, et al. “Observation of the Spin Hall Effect in Semiconductors.” Science 306 (2004): 1910- 1913. Print.
Ramsden, Eddie. Hall-effect sensors: theory and applications, New York, NY:Elsevier, 2006. Print.