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brybot
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I am trying to measure the relative permeability of a few materials, but the numbers I'm getting don't quite make sense. Maybe someone here can figure out what might be going wrong.
My setup is as follows. I'm making solenoids using 30 AWG magnet wire wrapped around ferrite, steel and wood cores. I'm doing a single layer of wire and I get about 3600 turns per meter, however the solenoids themselves are about 1"L x 1/4"D. I have a hall effect sensor, the Allegro A1324 which has a sensitivity of 5mv/G. I'm placing the end of the solenoid directly against the sensor and measuring the voltage deviation with respect to current in the solenoid.
With the equation B=kμnI where n=N/L~=3600 I'm solving for the relative permeability k. So k=B/(μnI). At 2 amps I get readings of 201, 170, and 15 G for ferrite, steel, and wood respectively. Then solving for the relative permeability I get 2.2, 1.9 and 0.17. Wood should have something close to 1, so I know something is wrong. And the steel/ferrite should be at least 200.
Any ideas? Thanks
My setup is as follows. I'm making solenoids using 30 AWG magnet wire wrapped around ferrite, steel and wood cores. I'm doing a single layer of wire and I get about 3600 turns per meter, however the solenoids themselves are about 1"L x 1/4"D. I have a hall effect sensor, the Allegro A1324 which has a sensitivity of 5mv/G. I'm placing the end of the solenoid directly against the sensor and measuring the voltage deviation with respect to current in the solenoid.
With the equation B=kμnI where n=N/L~=3600 I'm solving for the relative permeability k. So k=B/(μnI). At 2 amps I get readings of 201, 170, and 15 G for ferrite, steel, and wood respectively. Then solving for the relative permeability I get 2.2, 1.9 and 0.17. Wood should have something close to 1, so I know something is wrong. And the steel/ferrite should be at least 200.
Any ideas? Thanks