|MadSci Network: Physics|
Hi Richie, The hall probe measures magnetic field strength, what we usually call B. There are two steps to get from magnetic field strength to the magnetic flux density. First you want to get the magnetic flux: B * area is the total amount of flux travelling through the entire area. The unit of magnetic flux is the "Weber." Next, the magnetic flux density is how much magnetic flux travels through one unit of area. So let's say you have 10 Webers travelling through an area of 1/2 square meter. Then the magnetic flux density is how many Webers flow through one square meter, or 20 Webers per square meter. So, you're looking for the magnetic flux density. What you should keep in mind is that the field may vary a little bit between your coils. So you can't just take the area of your coils and multiply that times one reading of your Hall Probe. What you should do is to take several readings of your hall probe at the exact center of the coils, and then move the hall probe gradually out towards the edge of the coils. You'll probably see the strength of the field drop. My guess is that you're interested in the flux density near the center of the coils, since that is usually where the magnetic field is the most constant and least bent. So for that, you can figure out an area over which the field is approximately constant, and use that area to find out the flux density in the middle. So what's the search coil? A search coil is a radio antenna in a metal detector, so I'm a little confused what you're using a search coil for here. Perhaps you can clarify how the setup is designed? Zack
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