1. Shielding and topological diagram

With the exception of coaxial cables, the other shielding components used in electronic equipment subject to electromagnetic interferences, behave as passive components, since, the shielding don’t disturb the functional voltages or currents. This criterion means that shielding has without effect on the normal operating of any equipment supplied by the power grid or a battery.

Shielding is one of a range of protective devices designed to attenuate strongly electromagnetics interferences, as suggested below:

• electromagnetic fields from near or far sources;

• conducted currents and voltages on power supply line;

• currents derived in earth, in any conductive wire or large metallic housing, (like a car body) so called ground potential reference (GPR)....