Gaussmeter also called the Tesla meter, is usually used as a measuring tool for surface magnetism. The picture below is a Japanese KANETEC gaussmeter that is widely used.
The working principle of the Gaussmeter is mainly based on the application of the Hall effect: when a current-carrying conductor is placed in a magnetic field, due to the Lorentz force, a transverse potential difference will appear in the direction perpendicular to both the magnetic field and the current. The Gaussmeter is based on The principle of the Hall effect is an instrument for measuring magnetic fields. The Hall probe generates a Hall voltage due to the Hall effect in the magnetic field. The measuring instrument converts the magnetic field strength value based on the Hall voltage and the known Hall coefficient.
The current Gaussmeter is generally equipped with a unidirectional Hall probe, which can only measure the magnetic field strength in one direction, that is, it can only measure the magnetic field strength perpendicular to the direction of the Hall chip. In some high-end measurement fields, there are also Hall probes that can measure three-dimensional magnetic fields. Through the conversion of the measuring instrument, the magnetic field strength in the X, Y, and Z axis directions can be displayed at the same time. The maximum magnetic field strength can be obtained through trigonometric conversion.
Gaussmeters can generally measure DC magnetic fields and AC magnetic fields. The unit can generally be switched to display the Gaussian unit Gs or the international unit millitelasmT. Among them, measuring DC magnetic fields is the most used in the industry.
If you need to measure a real-time magnetic field, you need to use the real function. The display will show the real-time magnetic field value and polarity.
When you need to capture the peak magnetic field and corresponding polarity during the measurement process, you need to use the hold function.
As shown in the figure below, the display will display "hold". The displayed value and polarity are the captured peak magnetic field and its corresponding polarity. If there is no display, it is a real function. You can also use the MODE button to switch to the AC magnetic field test mode. The "~" symbol appears on the screen as shown below.
Things to note when using a gaussmeter:
1. When using a gaussmeter to measure surface magnetism, do not bend the probe excessively. The Hall chip at the end should generally be lightly pressed against the surface of the magnet. This is to ensure that the measurement point is fixed, and on the other hand to ensure that the probe is in close contact with the measurement surface. , and it should be level with the measuring surface, but do not press hard.
2. Both sides of the Hall chip can be sensed, but the values and polarities are different. The scale side is used for convenient measurement and cannot be used as a measurement surface. The non-scale side is the measurement surface.
The Gaussmeter measures the magnetic field intensity Bz of the default vertical measurement surface. The following figure is a simulation diagram of an ordinary Z-axis magnetized magnet. It can be seen that the magnetic field is a vector, and the magnetic field intensity of the Z-axis can be considered as Bz=, Since the magnetic circuit path at the corners is the shortest, the magnetic field lines at the corners will be denser, and the magnetic field intensity B will be stronger than the center, but Bz will not necessarily be stronger than the center. It is just a limitation of the area measured by the Hall chip. Generally, the corners are measured. The magnetic field intensity is stronger than the center, at least not lower than the central magnetic field.
What needs special attention here is that when the magnetization directions are different, even on the same measuring surface, the difference in measured values is very large.
For those that need to measure dynamic or need to fit the magnetic field at different measurement positions into a waveform curve, a magnetic field scanner is needed. It still needs to be measured through a unidirectional or three-dimensional Hall chip, and then through the design of the measurement trajectory and data collection to output the magnetic field measurement curve.