Science Buddies: "Ask an Expert"

I am working on the project measuring magnetic fields. I didn’t buy the kit because it was cheaper to buy each item separately. My gaussmeter I made does not work even though I followed every instruction correctly. I checked the FAQ and it wouldn’t help. Somebody please help I only have until May 27.
https://share.icloud.com/photos/01q9kad ... Briarcliff

Hi huskyjake,

I'm assuming that you're working on the project described here:

https://www.sciencebuddies.org/science- ... tic-fields

Based on the photo you posted it appears that the components and jumpers are positioned as directed in the project procedure. And your multimeter seems to be correctly set and attached to the circuit. According to the project procedure the voltmeter should read about 2.5 volts, but yours shows 0 volts.

You might check the following:

Make sure you have a fresh battery.
Make sure the leads from the sensor and the transistor are fully inserted into the breadboard.
Make sure all of the jumper wires are fully inserted into the breadboard.
It's hard to confirm from your photo that the sensor and transistor are plugged into the correct breadboard positions, so you might want to check those again.

I hope this helps. Please ask again if you have more questions.

A. Norman

Hi huskyjake,
I am not sure if you still need help with this but here are a few more things that you might want to check.

At the row where the you have the yellow wire, row 4 it looks like), please check and see if you have voltage there. (It should be around 5Vdc) If so, you can then say that the 7805 is working correctly and the problem is with the hall effect sensor part of the circuit. Also, on the safe side, please disconnect the battery and confirm that it does show 9V with your volt meter. (Just wanted to be sure that the meter is working)

Good Luck!
Willey