The Hall effect produces a voltage difference across a current-carrying conductor placed in a magnetic field. It was discovered in 1879 by Edwin Hall. When charges flow through a conductor, the Lorentz force causes electrons and holes to separate, producing an electric field perpendicular to the current and magnetic field. This Hall voltage can be used to determine properties of the conductor like carrier type and density. Modern applications of Hall effect sensors include current sensors, motor control, magnetometers, and blood flow measurement.
HALL effect - SemiConductors - and it's Applications - Engineering PhysicsTheerumalai Ga
A 20 mins discussion on the "HALL EFFECT and it's applications" of Semiconductors and a brief explanation about Hall Sensors with a derivation and video attached. Engineering Physics - important area of discussion for Anna University examination- seminar
explains about Poyntings theorem, boundary conditions, poissons and laplace equations and uniqueness theorem and its importance in Electromagnetic theory
Classification of magnetic materials on the basis of magnetic momentVikshit Ganjoo
I made this presentation for my own college assignment and i had referred contents from websites and other presentations and made it presentable and reasonable hope you will like it!!!
HALL effect - SemiConductors - and it's Applications - Engineering PhysicsTheerumalai Ga
A 20 mins discussion on the "HALL EFFECT and it's applications" of Semiconductors and a brief explanation about Hall Sensors with a derivation and video attached. Engineering Physics - important area of discussion for Anna University examination- seminar
explains about Poyntings theorem, boundary conditions, poissons and laplace equations and uniqueness theorem and its importance in Electromagnetic theory
Classification of magnetic materials on the basis of magnetic momentVikshit Ganjoo
I made this presentation for my own college assignment and i had referred contents from websites and other presentations and made it presentable and reasonable hope you will like it!!!
Out-of-Core Construction of Sparse Voxel OctreesJeroen Baert
Voxel-based rendering has recently received significant attention due to its potential in the context of efficiently rendering massively large and highly detailed scenes. Unfortunately, few or no scenes are available in the form of sparse voxel octrees. In this paper, we present an out-of-core algorithm for constructing a sparse voxel octree from a triangle mesh. Our algorithm allows the input triangle mesh, the output sparse voxel octree, and, most importantly, the intermediate high-resolution 3D voxel grid, to be larger than available memory. We demonstrate that our out-of-core algorithm can construct sparse voxel octrees from triangle meshes using only a fraction of the memory required by an in-core algorithm in roughly the same time, and that our out-of-core algorithm can also handle extremely large triangle meshes.
A Project made for my School in the 10th Grade explaining the differences and working of AC and DC Generators.
Contents:
-Introduction
-Electromagnetic induction
-EMF- Electromotive Force
-Fleming’s Right Hand Rule
-Components of a Generator
*Rotor
*Armature
*Coil
*Stator
*Field electromagnets
*Brushes
-A.C. generators
-Commercial A.C generators
-DC generators
-Principle
-Working
-Differences between AC and DC
2. Definition
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 both current and the
magnetic field.
3. Discovery
The Hall effect was discovered in 1879
by Edwin Herbert Hall while working on
his doctoral degree at the Johns
Hopkins University in Baltimore,
Maryland, USA.
5. Theory
• A static magnetic field has no effect on
a charged particle unless it is moving.
• When charges flow, a mutually
perpendicular force (Lorentz force) is
induced on the charge.
• Now electrons and holes are separated
by opposite force.
6. Theory
• This produces a electric field which
depends upon cross product of magnetic
intensity [H] and current density [J]
Eh=R(JxH)
• R is called Hall Coefficient
• Consider a Semiconductor bar along X-
axis, Magnetic field along Z-axis. Thus Eh
will be along Y-axis.
17. Working
1. Conductor is kept
in a magnetic
field.
2. Current is passed
through it.
3. We get a reading
in voltmeter kept
perpendicular to
the conductor.
18. Recording Observation
• After setup the
Hall Voltage is
measured as a
function of –
1. Current keeping
magnetic field
constant.
2. Magnetic field
keeping current
constant.
Current
HallVoltage
19. Conclusions
1. Hall Coefficient can be determined using
Rh=Vhb/IH
2. Hall effect can be used to determine the signs of
current carrier in metals and semiconductor.
3. A straight graph between Hall voltage & Current
and between Hall voltage & Magnetic field
confirms their linear relationship. This point has
important meaning as hall effect can be
effectively used to determine current or magnetic
field, when other is known.
20. Precautions
1. Hall Voltage should be measured very
carefully and accurately.
2. Distance between pole pieces of
Electromagnet should not be changed
during the whole experiment.
3. Current passing through
semiconductor slab should be strictly
within permissible limit.
21. Applications
Hall effect devices produce a very low
signal level and thus require
amplification. In early 20th
century
vacuum tube amplifiers were expensive
and unreliable. But with the
development of the low cost integrated
circuit the Hall effect sensor became
suitable for mass application.
22. Current Sensor
• When electrons flow through
a conductor, a magnetic field
is produced.
• Thus, it is possible to create a
non-contacting current
sensor. This has several
advantages:
1. No additional resistance (a
shunt) need be inserted in
the primary circuit.
2. Also, the voltage present
on the line to be sensed is
not transmitted to the
sensor, which enhances
the safety of measuring
equipment.
Hall effect current sensor with
internal integrated circuit amplifier.
23. Electric Motor Control
Some types of brushless
DC electric motors use Hall
effect sensors to detect the
position of the rotor and
feed that information to the
motor controller. This
allows for more precise
motor control.
24. Magnetometer
• Smart phones like iPhone
3GS are equipped with
magnetic compass.
• These compass measure
Earth‘s magnetic field using
3-axis magnetometer.
• These magnetometer are
sensors based on Hall Effect.
• These sensors produce a
voltage proportional to the
applied magnetic field and
also sense polarity.
25. Blood Flow
Similar to the Hall effect, the velocity of blood
can be measured by its ions.
next
26.
27. Hallresistance-Rxy(ohms)
The classical Hall effect
• Lorentz force likes to deflect jx
• However, E-field is set up which balances Lorentz force
• Balance occurs when Ey = vxBz = Vy/ly
• But jx = nevx (or ix = nevxAx)
⇒ Rxy = Vy / ix = RH Bz × (ly /Ax), where RH = 1/ne
Where ly is transverse width of sample and Ax is the transverse cross sectional area
the sample, i.e. depends on shape of sample
0 2 4 6 8 10
200
0
1200
1000
800
600
400
1400
Slope related to RH
and sample dimensions
Magnetic field (tesla)
Ax
ly
29. In Cars
29
• Used expansively in rotating systems
• Anti-lock brakes, motor feedback, ignition
Via Power Systems Design, Ltd. Via Draper, 2005
Richard Beck - Physics 141A, 2013
30.
31. In Space
• Hall Effect thruster
• Trap electrons in a magnetic field, electrons
ionize propellant, creates thrust
Richard Beck - Physics 141A, 2013 31
32. And there are many more
applications of hall effect…
