Hello, I am using a LakeShore 455 DSP Gaussmeter for measuring AC magnetic field produced from a Helmholtz coil arrangement. I have set the meter to RMS mode. However, the readings are highly fluctuating. When I set the range to 350 Oe, it is starting from a high value (about 220 Oe) and then decreasing to zero. If I set it to AUTO RANGE ON, it is still fluctuating. Note that I have sent alternating current (sine wave) of 1 kHz frequency through the Helmholtz coils. I am supposed to get ~ 5 Oe AC magnetic field (I had measured it using this same gaussmeter and same probe, about 3-4 months ago). I have tried with both the Narrow and Wide band filter mode. In both modes, the meter is unable to show the frequency of the AC field. In Narrow band mode, the field reading is fluctuating and the frequency reading is 0 Hz. In wide band mode, it is showing about 0.2 Oe and some arbitrary frequency (8 or 9 kHz).
Also please note that, in DC mode it is showing a stabilized reading.
I hope it is not a problem of the probe. I think it might be a problem of the Gaussmeter (particularly when it is set in RMS mode). Please help me to solve the problem.
Post by Lake Shore Jeff M on Feb 8, 2019 8:17:28 GMT -5
Since the meter is unable to determine the frequency, we may need to have the Model 455 and probe returned to the factory for analysis. Before we do that, please let me know the model number of the probe you are using.