Artificial E and H fields

EMI "electromagnetic interference" is a term used to designate artificially generated electromagnetic pollution, meaning electric (E) fields and magnetic (H) fields.

Such fields arise wherever there is a voltage or a current. All types of radio broadcasting and TV transmitters produce electromagnetic fields, and they also arise in industry, business and the home, where they affect us even if our sense organs perceive nothing.

Electromagnetic fields

There are two types of electromagnetic fields: Constant and Alternating.

Constant fields

Here, the direction does not change. Examples include the Earth’s natural electric and magnetic fields, the magnetic fields used to run subways and streetcars, and the fields used in magnetic resonance imaging (MRI).

Alternating fields

Here, the direction does change. The number of periods per second is equal to the frequency, and the unit of frequency is Hertz (Hz).

Low-frequency fields (LF)

Alternating fields up to 30 kHz.

HF, RF and microwave fields

Alternating fields from 30 kHz to 300 GHz

Unit of electric field strength: Volts per meter (V/m)

Units of magnetic field strength: Amperes per meter (A/m) or magnetic flux density (B) in Tesla (T) or Gauss (G)