Harsh Shukla

Hall Sensor

HALL EFFECT AND

ITS APPLICATIONS

HALL EFFECT THRUSTER

The Hall effect was discovered in 1879 by EdwinHerbert Hall while working on his doctoral degree atthe Johns Hopkins University in Baltimore, Maryland,USA

Discovered 18 years before the electron.

DISCOVERY

Edwin H Hall

The Hall effect is the production of a voltage difference(the Hall voltage) across a current carrying conductor(in presence of magnetic field), perpendicular to bothcurrent and the magnetic field.

WHAT IS HALL EFFECT?

When a current-carrying conductor is placed into a magneticfield, a voltage will be generated perpendicular to both thecurrent and the field.

When a perpendicular magnetic field is present. A Lorentz forceis exerted on the electron. Due to which Electron moves inperpendicular direction to both current and Magnetic Field. Anddevelop a Potential difference across the conductor orsemiconductor.

THEORY

Creates internal electric potential, known as Hall voltage.

𝑉ℎ=𝐵∗𝐼

𝑛∗𝑒∗𝑑where ‘d’ is the thickness of the metal along the direction of

Magnetic field.

In metals:

In semiconductors:

HALL VOLTAGE AND HALL COEFFICIENT

Used as Magnetometers , i.e. to measure magnetic field.

Hall effect sensor is also used as Current Sensor.

Magnetic Position Sensing in Brushless DC Electric Motors

Automotive fuel level indicator.

Spacecraft propulsion.

And many more.

APPLICATIONS

MAGNETOMETERS

• Smart phones are equipped withmagnetic compass.

• These compass measure Earth‘smagnetic field using 3-axismagnetometer.

• These magnetometer are sensorsbased on Hall Effect.

• These sensors produce a voltageproportional to the appliedmagnetic field and also sensepolarity.

WORKING EXAMPLE OF HALL EFFECTSENSOR

CURRENT SENSOR

Hall effect current sensor with

internal integrated circuit amplifier.

When electrons flow through aconductor, a magnetic field isproduced.

This has several advantages:1.No additional resistance (a

shunt) need be inserted in theprimary circuit.

2.Also, the voltage present onthe line to be sensed is nottransmitted to the sensor,which enhances the safety ofmeasuring equipment.

Some types of brushless DC electric motors use Hall effectsensors to detect the position of the rotor and feed thatinformation to the motor controller. This allows for more precisemotor control.

POSITION SENSING IN BRUSHLESS DC

ELECTRIC MOTORS

The main principle of operation of such indicator is positionsensing of a floating element.

When Button magnet is mounted on the surface of a floatingobject. The current carrying conductor is fixed on the top of thetank lining up with the magnet.

As level of fuel rises, an increasing magnetic field is applied onthe current resulting in higher Hall voltage.

The fuel level is indicated and displayed by proper signalcondition of Hall voltage.

AUTOMOTIVE FUEL LEVEL INDICATOR

Floating element

Button Magnet

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