How ghost hunters use EMF meters
An EMF meter is an instrument that reads the fluctuation in electromagnetic fields. You should always take preliminary EMF readings at various places throughout the site. The locations of power lines, appliances and other sources of electromagnetic fields are also noted. Most normal readings are in the range of 9.0 – 30.0 on the EMF meter. These are typical EMF readings in a home. Anything that registers in the 2.0 to the 7.0 ranges and cannot be traced to a source is attributed to spirit activity. An example of a source would be a computer monitor. The closer you get to a natural source the higher the reading. A natural source should always appear in the same place and will not disappear. You should discard these readings.
When you get a short EMF reading in the 2.0 – 7.0 range which you do not get it again in the same location AND you do not find a natural EMF source then you have a positive EMF reading. It is scientifically impossible for low level and moving electromagnetic fields to occur naturally, yet we find these fields in areas where there is spirit activity reported. It is commonly accepted that spirits and/or the energy associated with them are the causes of these unexplainable EMF readings.
All EMF meters have different distance ranges but they all work generally the same. The range that the meter reads is come shaped like a flashlight beam coming from the front of the meter or the probe if the meter has one.