Understanding Magnetic Gauss of Magnets and Magnetic Therapy

WHAT IS GAUSS?

The Permanent Magnet Design and Application Handbook, by Lester Moskowitz provides the following definition:

gauss: The cgs unit of magnetic induction.

For clarification let us proceed to the definition of magnetic induction.

Induction, magnetic (general): The flux per unit area measured at right angles to the direction of the flux.

If after reading the above definitions you feel that you don’t know much more than you did before reading them, you are not alone.

Gauss is the most misunderstood term in magnetic therapy, greatly misused by some manufacturers who use manufacturer’s gauss rating to indicate the strength of their products, when in truth the strength of a magnet depends on:

a) Strength of material (manufacturer’s gauss rating)
b) Size and weight of the magnet

For example: The earth’s magnetic field is 0.5 Gauss and a refrigerator magnet is 10 Gauss.

Considering only these numbers one would think that a refrigerator magnet is more powerful than the earth. This of course is incorrect, the earth, due to its immense size has an immeasurably more powerful magnetic field.

There is no simple standard mathematical formula to calculate the strength of a particular magnet. Magnets used for bio-magnetic purposes are described as open-circuit magnets because they do not have supplemental ferro-magnetic parts to provide a complete path for the magnetic energy. Any type of “bar” magnet falls into this category. This would include magnets used in magnetic mattres pads, magnetic braces, magnetic wraps, magnetic supports, magnetic jewelry, magnetic bracelets, and encased magnetic blocks.

Generally, magnets used in magnet therapy products range from 300 to 3000 Gauss.

A gauss meter is an instrument which can be used to measure lines of magnetic flux at a specific point on a magnet, but that reading provides no information about the total energy of the magnet being tested or about how far the energy will project from its surface.

When describing magnetic power in terms of gauss, most manufacturers are referring to the manufacturer’s gauss rating of the magnetic material. This number will be the same for any size magnet made from the same material and often does not reflect the true strength of a particular magnet. Once again, it is not a measure of the total energy of the magnet.

The following photographs should illustrate the problems with using the manufacturer’s rating. The same coin is photographed with each magnet to illustrate its size relative to the coin.

Fig. 1 shows a neodymium-iron-boron magnet. The manufacturer’s rating for this magnet is 12,500 gauss. The flux density on the surface of this magnet, measured using a gauss meter, is 985 gauss. A simple magnetometer, another device used to measure field strengths, reads 2 gauss at a distance of 1/8" from the surface of the magnet.	Fig. 2 shows a ferrite ceramic magnet. The manufacturer’s rating for this magnet is 3850 gauss. The flux density on the surface of the magnet, measured using a gauss meter, is 565 gauss. The magnetometer reads 2 gauss at a distance of approximately 3/4" from the surface of the magnet.
Fig. 3 shows a ferrite ceramic magnet measuring 10 5/8" X 3 1/2" X 1". The manufacturer’s rating for this magnet is 3850 gauss (the same as the magnet in Fig. 2 above). The flux density on the large flat surface of the magnet measures 950 gauss at the end, 720 gauss on the sides and 465 gauss at the center. The magnetometer measures 2 gauss at a distance of approximately 20" from the surface of the magnet. From the illustrations above it should be obvious that the "gauss" readings don’t really provide any useful information. Although it has the highest numbers, the magnet in Fig. 1 is so small that the total magnetic energy is quite low and practically imperceptible at only a slight distance from its surface. It is therefore abundantly clear that it is difficult to market magnetic products on the basis of gauss as this does not give customers all the information needed to make an informed decision. The customer may be led to believe that he is being provided information about the magnetic product which he can use as a basis for comparison and for making an informed decision. In fact, this may not be the case.

At MagneticTherapyMagnets.com our we try to give our customers the most comprehensive information about each of our magnetic therapy products so that they can make an informed decision. With each of our products you will see the following information listed:

• Magnetic Material
• Manufacturer’s Gauss Rating
• Surface Gauss
• Magnetic Penetration

Each and every one of our magnetic products are designed with magnets that have the magnetic strength that is believed to be the most effective for its intended use.