Hall Effect Sensor
The basic principle to the Hall Effect sensor is based on a thin metal sheet of semiconducting material, such as copper, that carries the flow of an electrical current, normally supplied by a battery device. hall effect sensor is the sensor which can use the magnetic flux to convert it into a voltage signal.the voltage which is measure by the sensor not pretty much.
the value of the voltage is within the range of microns.hall effect sensor is mainly used to measure the speed of shaft and also use as position sensor.this lower amount of voltage can not be detected by the controller. so amplifier is used to increase the intensity of the voltage signal.
before discuss about the sensor, first i want to give you a little implementation about the hall effect .
What is hall effect
hall effect is the phenomenon which is developed when a magnetic field is applied perpendicular over a conductive dc circuit.when the dc supply is provided in the x-direction in a conductive plate and a magnetic field is also applied in the y-direction then hall effect is appear in the z-direction .
Working principle of hall effect sensor
if their is a conductive plate and a dc supply is applied in x-direction through the conductive plate. so due to application of the supply the electrons start move and the current will generate. but after some time if i produce some magnetic field in the perpendicular direction of the dc supply(y-direction) .then the electron deflected from their flow path. and these electrons placed in the upper direction of the plate.due to the polarity of the conductive plate positive ion also dense in the lower part of the conductive plate. this is due to the hall effect. so this results to give a voltage in the z-direction.
Hall Effect sensor circuit
hall effect sensor has three pin configuration 1 pin is refers as power supply,second pin is as ground and third pin as output signal .when we employed the hall effect sensor in any electrical circuit to detect the speed of the shaft then we put in the same designation condition and place a motor nearby the sensor.we also know the a dc motor consist of magnet and copper coil. when supply is provided to the motor a magnetic field is generated which the motor shaft to be rotate.
but this magnetic field also generate a hall effect in the hall effect sensor and corresponding voltage is produce at the output signal port of the hall effect sensor which is further connected to the amplifier which amplify the signal.this signal port of hall effect sensor is then connected to the a op-amp to convert the analog signal into the digital signal.this digital signal is reached at the micro-controller and specific task is being done by the system.
advantage using of the hall effect sensor
1.hall effect sensor does not affected by ambient condition such as humidity,dust
2.their is no contact between the sensor and object so unlimited time to use.
3.hall effect sensor can detect the zero speed.
4.these are basically made up of semiconductor which possesses low carrier density and high conductivity.
5.Hall effect sensors work in a wide temperature range, provide highly repeatable operation, and are capable of measuring a large current.
6A .high speed operation is possible.
Disadvantage using of the hall effect sensor
1.it is applicable only when the non-magnetic materials are used such as aluminum, glass.
2.maximum measurable thickness is about 10mm.
3.it can not measure the current when the distance is more than 10cm.
4.Temperature affects the electrical resistance of the element and the mobility of majority carriers and also the sensitivity of Hall Effect sensors.
5.there is also the possibility of offset of the voltage due to physical inaccuracy and non-uniformity of the material.
Analog output sensor applications include:
Current sensing, Variable speed drives, Motor control protection/indicators , Power supply sensing, Motion sensing, Diaphragm pressure gauge , Flow meters ,Direct current electricity Encoded switches, Rotary encoders , Ferrous metal detectors (biased Hall), Vibration sensors ,Magnetic toner density sensor,Rotational speed sensor
Digital output sensor applications include:
Wireless communication, Pressure sensors, Proximity sensors, Flow sensors, Valve position sensors, Lens position sensors, Shaft position sensors.
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