there are two permamnent bar magnets put with a south pole facing a north pole. there is a magnetic field in between the bar magnets. i need to use the hall probe to measure the field strentgh. the probe measures a hall voltage and i can convert this to magnetic field strength values using the calibration graph i have. the problem i have is that i think current must flow through the hall probe so to excite the electrons so they can be deflected once the probe is in the field. otherwise i will not be able to get any hall voltage reading. can someone explain to me that should there be current flowing through the hall probe? for me to get hall voltage readings or can i just place the hall probe in the field without any current flowing through the probe? and it just bieng connected to a voltmeter.