How to Use a Gauss Meter

Magnetometer (Measures in Both AC and DC Fields)

A Gauss meter, also known as a magnetometer, is an electronic instrument for measuring the strength of magnetic fields, usually in units of Gauss. They are used as metal detectors, to compare the relative strength of magnets, to measure the Earth's magnetic field, to measure magnetic effects in electronics, to test for possibly dangerous electromagnetic fields, and to find metals that might require demagnetization. The most common magnetometer probes are called Hall effect sensors. There are several other types, useful for better resolution at lower fields.

Instructions

1. Make sure there are no magnets around before zeroing out the display.

2. Zero out the reading.

   There may be more than one reading that needs zeroing out. It will be easy to tell because you will see multiple reset buttons. Do not expect to get the zero-reading to stabilize. Bouncing between +1 and -1 Gauss should be expected for an inexpensive Hall-effect meter.

3. Hold the probe flat against the magnet, if it's a flat magnet being measured (as opposed to an AC circuit).

   Move the magnet slowly along the probe, and record the highest steady reading. The reason for moving the probe is in case the point of highest sensitivity on the probe is not known exactly.

4. Hold the probe in place for several seconds against whatever object you want to measure the magnetic field from, until the reading stabilizes.

5. Change scales if the reading is too high or two low to register.

   If the field is still too intense to get a reading, compare the magnet to another of known intensity in the following way: use a shim between the magnet and probe to reduce the reading, and find another magnet, this time of known intensity, that gives the same reading using the same shim.

6. Measure the other side of the magnet also, if measuring magnets.

   Averaging the two readings increases accuracy.

Tips & Warnings

• Hall effect Gauss meters can also measure the magnetic field direction. To determine which direction the sign of the reading signifies, the meter model's manual should be consulted, as this would vary by model.

• A probe may wear with time, as the surface is scratched off by contact with objects being measured. The thickness of the probe should be measured with a micrometer when new, so that the wear can be monitored. Then the width of metal shim needed will be known. It would be glued on, taking care to clean the surfaces first. If you decide to do this, see the first reference for some important detail.

References

• How to Use a Gauss meter
• Comparison of Magnetometers