I was playing around with one of these Hall effect magnetic field sensors when I noticed something I thought was strange. I held a cylindrical magnet several centimeters from the tip of the sensor and read the reading as around 5 mT. Upon reversing the magnet, the reading changed to around -8 mT (which is above its maximum rating). I was sure to keep the magnet a fixed distance from the sensor. The effect diminished greatly with distance, and the sensor appeared accurate at a range of around 10 cm.

I was curious as to why the sensor might produce different magnitudes dependent on the polarity of the magnet if the field is supposedly symmetrical. (Could it be that some part of the sensor is magnetized itself?)


1 Answer 1


Without being sure of my answer,i would say that this difference in magnitude has to do with the charges themselves.
The first time you did it,you pushed negative charges in one direction.When you reversed the polarity,then you already had a situation which was not in equilibrium as the first time.The first time you had a flow in which electrons and protons where moving in opposing directions but were mixed up.Now,you have separated them,so the second time that you measure them with the different polarity,you might get different results.
Try to measure the potential difference again but with the first polarity.If the potential difference is different in magnitude as your first measurement,then i believe i am right.
To be more exact as why those two different initial conditions of the current create different potential difference is a bit more advanced,so if you want an explanation then write it down in the comments.
Again,i am not entirely sure about the answer.


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