Editing Metal detector (section)

===Pulse induction===
At the same time, developers were looking at using a different technique in metal detection called pulse induction.<ref>{{cite web|url=http://electronics.howstuffworks.com/gadgets/other-gadgets/metal-detector4.htm|title=How Metal Detectors Work|date=23 May 2001}}</ref> Unlike the beat frequency oscillator or the induction balance machines, which both used a uniform alternating current at a low frequency, the pulse induction (PI) machine simply magnetized the ground with a relatively powerful, momentary current through a search coil. In the absence of metal, the field decayed at a uniform rate, and the time it took to fall to zero volts could be accurately measured. However, if metal was present when the machine fired, a small eddy current would be induced in the metal, and the time for sensed current decay would be increased. These time differences were minute, but the improvement in electronics made it possible to measure them accurately and identify the presence of metal at a reasonable distance. These new machines had one major advantage: they were mostly impervious to the effects of [[Mineralization (geology)|mineralization]], and rings and other jewelry could now be located even under highly [[Mineralization (geology)|mineralized]] [[black sand]]. The addition of computer control and digital signal processing have further improved pulse induction sensors.

One particular advantage of using a pulse induction detector includes the ability to ignore the minerals contained within heavily [[Mineralization (geology)|mineralized]] soil; in some cases the heavy mineral content may even help the PI detector function better.{{citation needed|date=March 2021}} Where a VLF detector is affected negatively by soil [[Mineralization (geology)|mineralization]], a PI unit is not.