Measuring Your Magnetism

AFTER you've done your research and concluded your experiments, it is time to prepare for the science fair. Ask specific questions about preparing for a science fair, including how to set up your display board, how to prepare a presentation, etc. (Please post questions about selecting a project or conducting your experiment by posting in the appropriate "area of science" forum.)

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Measuring Your Magnetism

Postby gmdamore26 » Mon Jan 21, 2013 6:43 am

After finally getting the bread board properly (we think) set up for this experiment, we have discovered that the alligator clips do not work when we connect to the multimeter to get a reading for the initial value of 2.5V. However, we get a reading of 3.59 when we do not use these clips.

This does not make any sense to us. We do not know why this is happening.
gmdamore26
 
Posts: 4
Joined: Mon Jan 21, 2013 6:08 am
Occupation: Student: 11th garde
Project Question: Measuring Magnetism: Building Breadboard
Project Due Date: January 23, 2013
Project Status: I am conducting my experiment

Re: Measuring Your Magnetism - please help

Postby gmdamore26 » Mon Jan 21, 2013 10:37 am

We are getting an initial reading of the voltage without a magnet of 3.5.

This number does NOT change when we place a magnet near the Hall Linear chip. We've tried many different ways to connect it and it still does not change.

Please advise!
gmdamore26
 
Posts: 4
Joined: Mon Jan 21, 2013 6:08 am
Occupation: Student: 11th garde
Project Question: Measuring Magnetism: Building Breadboard
Project Due Date: January 23, 2013
Project Status: I am conducting my experiment

Re: Measuring Your Magnetism

Postby gmdamore26 » Mon Jan 21, 2013 1:40 pm

We think the reason the magnets are not getting a measurement is because the IC HALL LINEAR SENSOR has been damaged due to all of our trial and error....

Unfortunately, this is not available and is on back order.

The picture you show on your website is confusing. It is not how the instructions are detailed. The Hall Sensor does not have the alligator clip on it as instructed. This is what cause us to blow our sensor. Now we were unable to complete our experiment until we get a new sensor which as I said is back ordered. You should advise people to purchase at least 2 of these since they are so extremely sensitive.
gmdamore26
 
Posts: 4
Joined: Mon Jan 21, 2013 6:08 am
Occupation: Student: 11th garde
Project Question: Measuring Magnetism: Building Breadboard
Project Due Date: January 23, 2013
Project Status: I am conducting my experiment

Re: Measuring Your Magnetism

Postby kgudger » Tue Jan 22, 2013 10:15 am

Hello:

I would think that you have probably damaged your sensor. If you plug it in backwards (i.e., connect pin 1 to ground and pin 3 to power) you most likely will ruin the sensor.

I know that the direct replacement for this part is A1324LUA-T, but you can probably use this part (and it's available): http://www.newark.com/allegro-microsystems/a1325lua-t/sensor-hall-effect-linear-sip-3/dp/89T7955?in_merch=Popular%20Products. The difference is the sensitivity of the part, the '25 is less sensitive. You will need to modify this part of the procedure:
The sensitivity of the Hall sensor IC (A1321EUA) described in this experiment is 5 mV/G. Therefore, to calculate the magnetic field strength, B, in gauss, you can use this equation:
B = 1000 × (V0 − V1) / 5.
Change the "5" to "3.25". Your data will be less accurate because you will have less voltage to work with (and more problems with noise.)

Keith
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Re: Measuring Your Magnetism

Postby gmdamore26 » Tue Jan 22, 2013 10:52 am

I overnighted a substitute sensor from digikey - however it's sensitivity is not same - it is only 1.3V so the readings for most of the electromagnets are not registering.

I may try that part if - it seems more sensitive than what we are using now. Thank you

***
Did overnight that sensor (3.25). It is better than the 1.3 that we were using. Thanks.
gmdamore26
 
Posts: 4
Joined: Mon Jan 21, 2013 6:08 am
Occupation: Student: 11th garde
Project Question: Measuring Magnetism: Building Breadboard
Project Due Date: January 23, 2013
Project Status: I am conducting my experiment


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