"The Electromagnetic Field Meter" - by John York
First of all, EMF detection equipment was not designed to detect "ghosts". These meters were designed for use in the detection of artificial currents in inside buildings, homes, and other structures.
The electromagnetic field meters were adapted into paranormal research because of the theory that "ghosts" or "spirits" may cause interference with standard base readings of artificial currents.
Although this is theory, there have been correlations between unusual readings and paranormal activity.
For paranormal research, the investigator always searches for the artificial source of any reading that is different from baseline readings.
These readings could be things such as appliances, electrical outlets, breaker boxes, and even power lines in walls and floors.
Typically the investigator is looking for readings between 2 and 8 milligauss (mg), sudden drops or surges in readings that have no artificial source and another form of correlating "evidence" such as temperature drops, video, photos or any other factor that may indicate a possible "haunting".
The EMF meter is still being experimented with in regards to paranormal research. There are many factors that would make this piece of equipment seem useless in the detection of ghosts or anything involving a haunting.
However, we believe that as it is possible for a "ghost" to move physical objects, and even appear before us under the right circumstances, could they not manipulate a simple EMF meter?
More detailed info on EMF can be found here.
