How Accurate Are Magnetometers/Gaussmeters?

What is meant by a Magnetometer?


The term magnetometer signifies an electrical device that assesses and measures the magnitude of a magnetic field existing in a particular space or place. The appliance can also calculate the value of the magnetic dipole moment that various types and kinds of magnetic materials, constituents, and substances possess. For instance, it can compute and estimate the factors for different and diverse ferromagnets.


A magnetometer computes and determines the magnitude of various parameters associated with a magnetic field by judging and estimating the influence of the magnetic dipole moment. It works by following and considering the effect of the element on the current. It gets induced in a given and specific conducting coil.


In addition to that, a few unique sorts of magnetometers can establish the values of other factors related to a magnetic field. These points of consideration can include their strength, relative change, direction, and so on.


What is meant by a Gaussmeter?


A gaussmeter refers to another sort of electrical instrument that calculates parameters associated with a magnetic field. To be precise, it helps determine its direction and computes the value of its intensity.


However, a gaussmeter works solely with and on a small-sized and constricted range of the magnetic field.


A gaussmeter comes with various components, including a gauss probe or sensor, a meter, and a cable attaching or connecting the two parts. The device works on the principle or basis of the Hall Effect. In 1879, the phenomenon got discovered for the first time by Edwin Hall. In recent times, a gaussmeter also gets acknowledged and branded as the modern or contemporary version or adaptation of a gauss magnetometer.


The device can determine the values of the dynamic or moving electromagnetic fields related to alternating current (AC). It can also do so for the stable and steady magnetic fields associated with direct current (DC). A gaussmeter works to represent the computed measurements and data of an electromagnetic wave in different units. It can display it in Gauss (G), microTesla (µT), milliTesla (mT), or milliGauss (mG).


What is meant by the Accuracy of an Electrical Instrument?


The accuracy of an electrical instrument refers to its ability or capability to measure and calculate the most accurate value. In simpler terms, it represents the closeness the computed magnitude has to the true or standard value.


Hence, the more accurate reading is, the better is the result or performance of the electrical device or appliance.


The accuracy of any electrical instrument can get increased by taking or obtaining the values of small readings instead of large grouped ones. It helps curb the risks and possibilities of errors that can arise in the calculations. It stands true for any device, be it a magnetometer or a gaussmeter.


Overall, the accuracy in any system can get classified into the following:


  • Point Accuracy


Point accuracy signifies that the correctness of the readings taken by an electrical instrument lies solely at a specific point or position on its scale. It does not provide any knowledge or information about the total and general accuracy of the entire system.


  • Scale Range Percentage Accuracy


Using this method, the uniform range of scale determines and estimates the accuracy of an electrical instrument. For example, let us suppose that a thermometer has a scope that can go up to 100 degrees Celsius. We can consider its accuracy to remain about ±0.1 percent. It implies that the readings are correct or close to the actual value even if the measured value decreases or increases by approximately 0.1 percent. Up to that, the error can get neglected. However, if the reading exceeds that limit, the estimated value is considered to have a high-value error.


  • True Value Percentage Accuracy


In this type of accuracy calculation, the correctness of the reading depends on the true value.


The precise value gets neglected for up to ±0.5 percent of the true value.


What is meant by the Precision of an Electrical Instrument?


The precision of an electrical instrument refers to two or more readings that are close to one another. Its magnitude differs due to the interference of observational error. The precision gets used to finding the reproducibility or consistency of the calculation.

The numeric of significant figures and the conformity form the characteristic parameters of the precision.


A high precision signifies that the estimated value or result of any measurement comes out to be consistent. In other words, the repeated magnitude of the readings gets obtained. Conversely, low precision implies that the value of the calculations varies. However, it is not a stated and universal fact that high precision would give accurate results.


How Accurate is a Magnetometer or a Gaussmeter?


For a magnetometer or a gaussmeter, accuracy signifies the difference between the measured magnitude and the true value. It is so for the intensity of a magnetic field. In simpler terms, it portrays how inaccurate the data is or the influence of different and distinct error types in the calculations.


Now, the factor of noise comes in. Noise refers to the inherent background fluctuations that the output of a sensor experiences in an environment having no magnetic field. All sensing technologies come with their noise. Its range can vary from femtoTesla (10⁻¹⁵) and nT (10⁻⁹) to microTesla (µT). Fluxgate sensors have a noise of pT level (10⁻¹²). It defines the most insignificant magnetic field that can get measured.


Let us take the example of a magnetometer. Suppose it can measure up to 101 microTesla. Let us consider it in a total magnetic field of 100 microTesla. In this case, the electrical device shows and possesses an accuracy of 1%. It may also have 1 pT noise and can measure 101.000001 µT. Therefore, a 1% error remains in the true reading.


Some magnetometers and gaussmeter can reach high levels of accuracy at fraction levels of a percent. To summarize, these instruments can deliver high precision results having minimal difference from the true value of the magnetic field intensity.

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