For example, transformers change the high voltages used by transmission lines to the lower voltages used by distribution lines. Circuit breakers are used to turn lines on and off. In most practical situations, a battery-operated appliance is unlikely to induce electric current in the person using the appliance. Induced currents from AC fields have been a focus for research on how EMFs could affect human health. A. Power lines, electrical wiring, and appliances all produce electric and magnetic fields.
EMFs are invisible lines of force that surround any electrical device.
Electric and magnetic fields have different properties and possibly different ways of causing biological effects. However, both electric and magnetic fields weaken with increasing distance from the source. Even though electric and magnetic fields are present around appliances and power lines, more recent interest and research have focused on potential health effects of magnetic fields. No such associations have been found with measured electric fields. The higher the frequency, the shorter the distance between one wave and the next, and the greater the amount of energy in the field.