Electromagnetic fields

Electric and magnetic fields are invisible areas of energy (also called radiation)

that are produced by electricity, which is the movement of electrons, or current. through a wire.

An electric field is produced by voltage, which is the pressure used to push the electrons through the wire, much like water being pushed through a pipe. As the

voltage increases, the electric field increases in strength. Electric fields are measured in volts per meter (V/m).

 A magnetic field results from the flow of current through wires or electrical devices and increases in strength as the current increases. The strength of a magnetic field decreases rapidly with increasing distance from its source. Magnetic fields are measured in microtesla 

Electric fields are produced whether or not a device is turned on, whereas magnetic fields are produced only when current is flowing, which usually requires a device to be turned on. Power lines produce magnetic fields continuously because current is always flowing through them. Electric fields are easily shielded or weakened by walls and other objects whereas magnetic fields can pass through buildings, living things and most other materials.