Fluxgate Magnetometers
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[music] Narrator: A fluxgate magnetometer works essentially like a compass.
But, instead of a spinning needle, electromagnets are used to measure magnetic
fields. To build one, we start with a bar of ferromagnetic metal.
If you wrap a coil of wire around the bar and run an electric current
through it, the bar becomes magnetized and generates its own magnetic field.
Reverse the current, and the field reverses direction. If you do this
over and over again, you can see that the two directions cancel each other out.
However, when an external magnetic field is present, the two directions
are thrown out of balance, allowing you to measure the external field.
Finally, by combining multiple fluxgate sensors, you can measure a magnetic field in three
dimensions.
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