Fluxgates By: Riley Vollmer

What a Fluxgate is 2 Ferromagnetic bars (Cores) 2 Ferromagnetic bars (Cores) Coils wound around Each core but in opposite directions Coils wound around Each core but in opposite directions An alternating current (AC) running through the coils An alternating current (AC) running through the coils A third coil surrounding both cores and primary coils A Frequency Meter (Hz)

How it Works I The alternating current running through the coils causing a large, inducing magnetic field, which in turn induces a magnetic field in the 2 cores The alternating current running through the coils causing a large, inducing magnetic field, which in turn induces a magnetic field in the 2 cores The Cores’ magnetic fields are equal strengths but opposite orientations The Cores’ magnetic fields are equal strengths but opposite orientations The secondary coil picks up a voltage potential from the magnetic field in the cores The secondary coil picks up a voltage potential from the magnetic field in the cores In the absence of another magnetic field (such as the earth) the voltage detected in secondary coil would be zero because of the opposite but equal magnetic fields in the cores In the absence of another magnetic field (such as the earth) the voltage detected in secondary coil would be zero because of the opposite but equal magnetic fields in the cores

How it Works II When an external magnetic field is placed parallel to the cores, one core will produce a magnetic field in the same direction and reinforce it, the other core will have an induced field which is in the opposite direction and smaller.

How it Works III The difference in fields is enough to create a measurable voltage in the secondary coil, which is proportional to the strength of the magnetic field in the direction of the cores The difference in fields is enough to create a measurable voltage in the secondary coil, which is proportional to the strength of the magnetic field in the direction of the cores The voltage is measured by the Frequency meter The voltage is measured by the Frequency meter

My Experiment Using 2 homemade fluxgates (Dr. Swez’s, and my own) I will try to determine the magnetic field of certain objects Using 2 homemade fluxgates (Dr. Swez’s, and my own) I will try to determine the magnetic field of certain objects 3 Days before the experiment Dr. Swez and I moved all metal influences away from his fluxgate and powered it up, so that it could settle down into a constant measurement 3 Days before the experiment Dr. Swez and I moved all metal influences away from his fluxgate and powered it up, so that it could settle down into a constant measurement

Information Diamagnetic Materials – Small, negative field Diamagnetic Materials – Small, negative field Paramagnetic Material – Only observed at low temperatures, small, positive field Paramagnetic Material – Only observed at low temperatures, small, positive field Ferromagnetic Material – Only observed at low temperatures with varying fields Ferromagnetic Material – Only observed at low temperatures with varying fields

My Experiment (Continued) Once the Fluxgate has been stabilized I began to test out different types of metal ; brass, aluminum, and steel Once the Fluxgate has been stabilized I began to test out different types of metal ; brass, aluminum, and steel By finding the difference in frequency from before and after the metal is introduced into the Fluxgate’s field, and using Dr. Swez’s Calibration chart, I can find the magnetic field in micro Tesla. By finding the difference in frequency from before and after the metal is introduced into the Fluxgate’s field, and using Dr. Swez’s Calibration chart, I can find the magnetic field in micro Tesla.

Data Steel Steel.9726 Brass Brass.0636 Aluminum Aluminum.0913

Calibrations

Conclusion Upon testing I have found that steel has a positive magnetic field, brass normally has a small negative field, and aluminum also has a small negative field most of the time. My data varied from trial to trial because of the magnetic influence of my non- stop testing. The Fluxgate may have gained a small permanent charge to its field. The data I have presented is only the average of 3 trials for each metal. Upon testing I have found that steel has a positive magnetic field, brass normally has a small negative field, and aluminum also has a small negative field most of the time. My data varied from trial to trial because of the magnetic influence of my non- stop testing. The Fluxgate may have gained a small permanent charge to its field. The data I have presented is only the average of 3 trials for each metal.