How does a calibrated Hall Probe work?

In summary, a calibrated Hall Probe is a device that measures magnetic fields by using the Hall effect, which is the creation of a voltage difference across a conductor when a magnetic field is applied perpendicular to the current flow. The probe consists of a conductor with a current running through it, placed in a magnetic field. The resulting voltage is measured and calibrated to determine the strength and direction of the magnetic field. This process is used in various industries, such as in manufacturing and research, to accurately measure and map magnetic fields.
  • #1
Yoriko
9
0
I'm supposed to plan an experiment using a calibrated hall probe to investigate the relationship between Magnetic field strength (B) of a coil and the distance (x) from the centre of the coil.

I'm supposed to be able to take direct readings from the calibrated hall probe to calculate B, but how to? Is the hall probe supposed to be connected to something else?
 
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  • #2
There are several implementations of the linear Hall Effect probes used for magnetic field measurement. The simplest architecture is similar to a Wheatstone bridge, with two terminals for applied voltage, and two for a differential voltage output (floating outputs). The applied dc input voltage should be a regulated voltage, usually 5V or 6V. Use a 7805 or 7806 IC regulator if necessary.The differential output voltage is usually about 0.2 mV per Gauss to 2 mV per Gauss, with an output impedance of several k-ohms. The output voltage usually has a temperature coefficient. These are 4-terminal probes. Use a floating digital voltmeter (battery operated is best) with 1 mV or better resolution, and a 10 meg input impedance.

Some linear probes have a built-in differential amplifier (with some voltage gain) with temperature compensation. These are usually 3-terminal probes, with the output voltage measured with respect to the negative input voltage terminal. For a 6V input probe, the output voltage for zero Gauss is 3V.

Unlike some other probes, like proton nuclear magnetic resonance (NMR), the Hall Effect probes are usually only about ±20% calibration, unless specifically hand-calibrated.

Bob S
 
  • #3
Bob S said:
There are several implementations of the linear Hall Effect probes used for magnetic field measurement. The simplest architecture is similar to a Wheatstone bridge, with two terminals for applied voltage, and two for a differential voltage output (floating outputs). The applied dc input voltage should be a regulated voltage, usually 5V or 6V. Use a 7805 or 7806 IC regulator if necessary.The differential output voltage is usually about 0.2 mV per Gauss to 2 mV per Gauss, with an output impedance of several k-ohms. The output voltage usually has a temperature coefficient. These are 4-terminal probes. Use a floating digital voltmeter (battery operated is best) with 1 mV or better resolution, and a 10 meg input impedance.

Some linear probes have a built-in differential amplifier (with some voltage gain) with temperature compensation. These are usually 3-terminal probes, with the output voltage measured with respect to the negative input voltage terminal. For a 6V input probe, the output voltage for zero Gauss is 3V.

Unlike some other probes, like proton nuclear magnetic resonance (NMR), the Hall Effect probes are usually only about ±20% calibration, unless specifically hand-calibrated.

Bob S

:confused: Hm I'm not taking so high level physics yet so I don't really understand. So basically the hall probe is connected to a Gauss meter so direct readings of magnetic field strength can be obtained?
 
  • #4
Yoriko said:
I'm supposed to plan an experiment using a calibrated hall probe to investigate the relationship between Magnetic field strength (B) of a coil and the distance (x) from the centre of the coil.

I'm supposed to be able to take direct readings from the calibrated hall probe to calculate B, but how to? Is the hall probe supposed to be connected to something else?

It needs to be connected to a meter. Most probes are calibrated to match a given meter.

for instance:

http://www.lakeshore.com/mag/ga/gm410po.html
 
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  • #5
MagnetDave said:
It needs to be connected to a meter. Most probes are calibrated to match a given meter.

for instance:

http://www.lakeshore.com/mag/ga/gm410po.html

Ok thanks! :smile:
 
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  • #6
Yoriko said:
:confused: Hm I'm not taking so high level physics yet so I don't really understand. So basically the hall probe is connected to a Gauss meter so direct readings of magnetic field strength can be obtained?
You could get one of these sensors from AllegroMicro (sometimes available as a free sample) and read it out with a standard digital voltmeter:

http://www.allegromicro.com/en/Products/Part_Numbers/1301/1301.pdf

If you need an absolute calibration better than than the standard specification, make a small electromagnet and do it yourself.

Bob S
 

FAQ: How does a calibrated Hall Probe work?

1. How does a calibrated Hall Probe measure magnetic fields?

A calibrated Hall Probe measures magnetic fields by utilizing the Hall effect, which is the creation of a voltage difference across a conductor when it is placed in a magnetic field. The probe contains a thin strip of conducting material with a current flowing through it, and when it is placed in a magnetic field, the electrons in the conductor experience a force that causes them to accumulate on one side of the strip. This separation of charge creates a measurable voltage difference that can be used to determine the strength of the magnetic field.

2. What is the purpose of calibrating a Hall Probe?

The purpose of calibrating a Hall Probe is to determine its sensitivity and accuracy in measuring magnetic fields. Calibration involves subjecting the probe to known magnetic fields and comparing the measured values to the actual values. This allows for any errors or deviations to be identified and corrected, ensuring that the probe provides reliable and accurate measurements.

3. How is a Hall Probe calibrated?

A Hall Probe is typically calibrated by subjecting it to a series of known magnetic fields, ranging from low to high strength. The resulting voltage readings are then compared to the expected values, and adjustments can be made to the probe if needed. This process is repeated until the probe consistently provides accurate measurements.

4. Can a Hall Probe be calibrated for different types of magnetic fields?

Yes, a Hall Probe can be calibrated for different types of magnetic fields, such as static or alternating fields. The calibration process may vary depending on the type of field being measured, but the overall goal remains the same: to ensure the probe provides accurate readings.

5. How often should a Hall Probe be calibrated?

The frequency of calibration for a Hall Probe will depend on its intended use and the specific manufacturer's recommendations. In general, it is recommended to calibrate the probe at least once a year, or more frequently if it is used frequently or in harsh environments. If the probe is dropped or damaged, it should also be recalibrated to ensure accuracy.

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