Science Buddies: "Ask an Expert"

My son and I are trying to do the Measure your Magnetism experiment.
https://www.sciencebuddies.org/science- ... p030.shtml

We assembled the breadboard meter and connected my Fluke 79III meter to test.

I get 4.99 volts output from the voltage regulator and ~2.489 volts output from the Hall Effect sensor. I did receive the correct sensor, A1324LUA-T, from Newark.

The issue is that every magnet we have tried gives almost the identical reading.

The readings I am getting are either 0.030 or 4.91 depending on the polarity.

Are the magnets we are trying too strong for the sensor? That is what I am beginning to think.

I will look for some weaker magnets and see if that makes a difference.

Anything else I might be overlooking?

Thanks,
Reece & Russell

The voltage from the regulator fine, as is the voltage from the sensor when there are no magnets nearby. The datasheet (http://www.allegromicro.com/en/Products ... 4/1324.pdf) explains in great detail how a south polarity magnet increases the voltage output from 2.5 to 5V, and a north polarity magnet changes the output from 2.5 to 0V.

If you only see those extreme voltages on your meter, then the sensor is much too sensitive and yes, your magnet is probably way too strong. However, if you start with the magnet really far away and slowly move it closer, you should see the voltage begin to increase or decrease until it hits the extreme. If you start seeing it change when you're still a good distance away, you may need to change the procedure or find a wimpier magnet.

Howard