Hall Effect Transducer Or Hall Effect Sensor.pptx

HALL EFFECT TRANSDUCER OR HALL EFFECT SENSOR

THEORY OF THE HALL EFFECT • The Hall effect was discovered by Dr.Edwin Hall in 1879. When a current – carrying conductor is placed into a magnetic field, a voltage will be generated perpendicular to both the current and the field. This principle is known as the Hall effect .

• The basic principle of the Hall effect. • It shows a thin sheet of semiconductor • material (Hall element ) through which a current is passed . The output connections are perpendicular to the direction of current . When no magnetic field is present, distribution is uniform and no potential differences is seen across the output. When a perpendicular • magnetic field is present .Lorentz force is exerted on the current .This force disturbs

the current distribution resulting in a potential differences (voltage) across the output. This voltage is known as Hall volatge. The interaction of the magnetic filed and the current is related by the equation, VH is directly proportional to the product of the current and the magnetic field.

If the magnetic field is removed, the Hall voltage disappears . If the magnetic field is reversed, the Hall voltage will also be reversed.

HALL SENSOR • Many type of sensors use the Hall effect to sense the presence of magnetic fields.

• A constant current runs through a conductive Hall strip inside the sensor. Then the rotating magnet near the Hall sensor. The alternating field from this rotating magnet will cause an alternating Hall voltage to be generated across the hall strip. This waveform is a alternating voltage waveform. This alternating voltage waveform is fed into the digital circuitry. This digital circuitry convents alternating voltage waveform into square waveform.

• Sensors are available with a verify of output voltages and polarities. The sensor is placed in the south magnetic pole, the sensor is turned ON, and then south pole is removed. • Now, the sensor is placed in north magnetic pole, the sensor is turned OFF. • MATERIALS FOR HALL ELEMENT: • 1.Gallium arsenide, • 2.Indium arsenide, • 3.Indium phosphide, • 4.Indium antimonide.

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