What is Hall Effect and How Hall Effect Sensors Work
Summary
TLDRIn this educational video from howtomechatronics.com, Dan Luksky explains the Hall effect and its application in sensors. The Hall effect, discovered by Edwin Hall in 1879, is a phenomenon where a voltage is generated across a conductor when a magnetic field is applied perpendicular to the current flow. Hall effect sensors, which are prevalent in modern technology, are used in various applications such as wheel speed sensors in vehicles, MEMS compasses, and proximity sensors. The video delves into the working principles of these sensors, highlighting the differences between analog and digital output sensors, and their specific uses in measuring magnetic fields and detecting positions in mechanical systems.
Takeaways
- 🧲 The Hall effect is a method for measuring magnetic fields discovered by Edwin Hall in 1879.
- 🚗 Hall effect sensors are widely used in vehicles for wheel speed sensing, and as position sensors for crankshafts or camshafts.
- 🔧 They are also utilized as switches, MEMS compasses, and proximity sensors in various applications.
- 🔬 The experiment in the video demonstrates how a magnetic field disturbs the flow of charge carriers in a conductive plate, resulting in a measurable voltage.
- 📊 Hall effect sensors typically provide a small voltage output, requiring built-in high gain amplifiers.
- 📡 There are two types of Hall effect sensors: analog, which offers a continuous output, and digital, which provides binary on/off outputs.
- 🔌 The analog sensor consists of a voltage regulator, Hall element, and amplifier, suitable for measuring proximity.
- 🛠️ Digital output sensors include a Schmitt trigger for hysteresis, useful in applications like limit switches in 3D printers and CNC machines.
- 🔄 Hall effect switches are used for detection and positioning in industrial automation systems.
- ⚙️ For measuring wheel speed or engine component positions, sensors use a Hall element and a permanent magnet near a toothed disk on a rotating shaft.
Q & A
What is the Hall effect?
-The Hall effect is a phenomenon where a measurable voltage is generated across a thin conductive plate when a magnetic field is applied perpendicular to the current flow. This effect was discovered by Edwin Hall in 1879.
How do Hall effect sensors measure magnetic fields?
-Hall effect sensors measure magnetic fields by detecting the deflection of charge carriers within a conductive material due to the Lorentz force when a magnetic field is present. This deflection creates a voltage difference across the material, which is proportional to the strength of the magnetic field.
What are some contemporary applications of Hall effect sensors?
-Hall effect sensors are used in various applications such as wheel speed sensors in vehicles, position sensors for crankshaft or camshaft, switches, MEMS compasses, proximity sensors, and in industrial automation systems for detection and positioning.
How do Hall effect sensors work in vehicles?
-In vehicles, Hall effect sensors are used as wheel speed sensors, crankshaft or camshaft position sensors. They provide accurate measurements of speed and position by detecting changes in the magnetic field as a toothed wheel or disk rotates.
What is the difference between analog and digital Hall effect sensors?
-Analog Hall effect sensors provide a continuous output proportional to the magnetic field strength, suitable for measuring proximity. Digital Hall effect sensors have two output states (on or off), often used as switches, with an additional Schmitt trigger for hysteresis and threshold levels.
Why do Hall effect magnetic sensors typically require a built-in amplifier?
-Hall effect magnetic sensors typically provide very small voltages, only a few microvolts per gauss, which are not sufficient for most applications. Therefore, they are usually manufactured with built-in high gain amplifiers to boost the signal to a usable level.
What is a Schmitt trigger and how does it relate to Hall effect sensors?
-A Schmitt trigger is an electronic circuit that provides hysteresis, allowing for two different threshold levels. In Hall effect sensors, it is used to ensure a clean switching between the on and off states, making it suitable for applications like switches and limit sensors.
How are Hall effect sensors used for measuring wheel speed or RPM?
-Hall effect sensors measure wheel speed or RPM by detecting the passing of teeth on a toothed disk attached to the rotating shaft. Each tooth passing near the sensor changes the magnetic field, causing the sensor output to switch states, generating a square wave signal that can be counted to calculate RPM.
What is the role of the tooth disk in Hall effect sensor applications?
-The tooth disk in Hall effect sensor applications is attached to the rotating shaft and has a small gap with the sensor. As the teeth pass by the sensor, they alter the magnetic field, causing the sensor to output a high or low signal, which can be used to determine position or speed.
Can you provide an example of a contemporary application of Hall effect sensors in industrial automation?
-In industrial automation, Hall effect sensors are used for detection and positioning, such as in 3D printers and CNC machines, where they act as limit switches or for precise control of mechanical movements.
Outlines
🧲 Introduction to Hall Effect and Sensors
In this video, Dan Luksky from howtomechatronics.com introduces the concept of the Hall effect, a phenomenon used to measure magnetic fields. Hall effect sensors are prevalent in modern technology, with applications in vehicles for wheel speed and position sensing, as well as in switches, MEMS compasses, and proximity sensors. The video aims to explain the working principle of these sensors by first demonstrating the Hall effect using a conductive plate experiment. When a current flows through the plate and a magnetic field is introduced, the charge carriers are deflected due to the Lorentz force, resulting in a measurable voltage difference across the plate. This discovery by Edwin Hall in 1879 is the foundation of Hall effect sensors. The video also mentions that these sensors typically provide a small voltage output, necessitating built-in amplifiers. Two types of Hall effect sensors are discussed: analog, which offers a continuous linear output, and digital, which provides binary output states. The analog type is suitable for proximity sensing, while the digital type, often incorporating a Schmitt trigger for hysteresis, is used for applications like limit switches in 3D printers and CNC machines, or for detecting and positioning in industrial automation.
Mindmap
Keywords
💡Hall Effect
💡Hall Effect Sensor
💡Magnetic Field
💡Lorentz Force
💡Analog Output
💡Digital Output
💡Schmitt Trigger
💡Proximity Sensor
💡Crankshaft and Camshaft Position Sensors
💡Square Wave Signal
Highlights
Hall effect is a common method for measuring magnetic fields.
Hall effect sensors have many contemporary applications.
Hall effect sensors are used in vehicles for wheel speed and position sensing.
They are also used as switches, MEMS compasses, and proximity sensors.
The Hall effect is demonstrated by a conductive plate with a current flowing through it.
A magnetic field disturbs the flow of charge carriers due to the Lorentz force.
Deflection of charge carriers results in a measurable voltage across the plate.
The Hall effect was discovered by Edwin Hall in 1879.
Hall effect sensors typically provide a small voltage, requiring built-in amplifiers.
There are two types of Hall effect sensors: analog and digital output.
Analog sensors provide a continuous linear output proportional to the magnetic field strength.
Digital output sensors provide binary states, often with a Schmitt trigger for hysteresis.
Hall effect switches are used as limit switches in 3D printers and CNC machines.
They are also used for detection and positioning in industrial automation systems.
Hall effect sensors measure wheel speed or RPM using a toothed disk and a permanent magnet.
The output of these sensors is a square wave signal, useful for calculating RPM.
For more tutorials, visit howtomechatronics.com.
Transcripts
hello dan luksky here from
howtomechatronics.com
in this video we will learn what is hall
effect and how hall effect sensors work
the hall effect is the most common
method of measuring magnetic field and
hall effect sensors are very popular and
have many contemporary applications
for example they can be found in
vehicles as wheel speed sensors as well
as crankshaft or camshaft position
sensors also they are often used as
switches mems compasses proximity
sensors and so on now we will go to some
of these sensors and see how they work
but first let's explain what is the hall
effect
here's the experiment that explains the
whole effect if we have a thin
conductive plate as illustrated and we
set current to flow through it the
charge carriers both flow in a straight
line from one to the other side of the
plate
now if we bring some magnetic field near
the plate we would disturb the straight
flow of the charge carriers due to a
force called lorentz force in such a
case the electrons will deflect to one
side of the plate and the positive poles
to the other side of the plate
this means if we put a meter now between
these two sides we will get some voltage
which can be measured so the effect of
getting a measurable voltage as we
explained above is called the hall
effect after edwin hall who discovered
it in 1879.
the basic hole element of the hall
effect magnetic sensors mostly provides
very small voltage of only few micro
volts per gauss so therefore these
devices are usually manufactured with
built-in high gain amplifiers
there are two types of hall effect
sensors one providing analog and the
other digital output the analog sensor
is composed of a voltage regulator a
whole element and an amplifier
from the circuit schematic we can see
that the output of the sensor is analog
and proportional to the whole element
output or the magnetic field strength
this type of sensors are suitable and
used for measuring proximity because of
their continuous linear output on the
other hand the digital output sensor
provides just two output states either
on or off this type of sensors have an
additional element as illustrated in the
circuit schematic
that's the schmitt trigger which
provides hysteresis or two different
threshold levels so the output is either
high or low for more details how the
schmitt trigger works you can check my
particular tutorial for that an example
of this type of sensor is the hall
effect switch they are often used as
limit speeches for example in 3d
printers and cnc machines as well as for
detection and positioning in industrial
automation systems
another contemporary applications of the
hall effect sensors are measuring wheel
speed or rpm as well as determining
position of crankshaft or camshaft in
engine systems
these sensors are composed of a hole
element and a permanent magnet which are
placed near a tooth disk attached on the
rotating shaft the gap between the
sensor and the teeth of the disc is very
small so each time a tooth passed near
the sensor it changes the surrounding
magnetic field which will cause the
output of the sensor to go either high
or low
so the output of the sensor is a square
wave signal which can be easily used for
calculating the rpm of the rotating
shaft
thanks for watching and for more
tutorials visit my official website
howtomechatronics.com
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