A gauss meter measures electric and magnetic fields (EMFs), which are
produced by power lines, electrical wiring, and electrical equipment
. Sometimes these
may cause problems with network devices and operation. EMFs are invisible lines
of force that surround any electrical device. Electric fields are produced by
voltage and increase in strength as the voltage increases. The electric field
strength is measured in units of volts per meter (V/m). Magnetic fields result
from the flow of current through wires or electrical devices and increase in
strength as the current increases.
Magnetic fields are measured in units
of gauss (G) or tesla (T).
Most
electrical equipment has to be turned on for a magnetic field to be produced,
since current must be flowing. Electric fields are present even when the
equipment is switched off, as long as it remains connected to the source of
electric power.
Electric fields are shielded or weakened by materials
that conduct electricity including trees, buildings, and human skin. Magnetic
fields pass through most materials and are therefore more difficult to shield.
Both electric and magnetic fields decrease as the distance from the source
increases.