A true magnetometer measures the intensity of a magnetic field. It does not emit anything.


An airport metal dectector (PI - pulse induction type) works by emitting a pulse about 100 times per second and looks at the reflected pulse decay time. Adding metal in the pulse chamber (where you walk in) increases the decay time.

It is different than a 'wand' type metal detector, which works like the ones you see beach comers using. That typically works by emitting a continious wave and measuring the frequency shift change that a metal object makes. This is a BFO (beat-frequency oscillator) type. Another type is a VLF (Very low frequency).

All work by emitting a pulse and/or a continious frequency. None by a static magnetic field.

See http://<a href="http://travel.howstu...urity2.htm</a>

Dave