Shielded enclosures
Electronics shields

In topological diagram of Figure 3, the shielded enclosures, are pointed out with symbols 4a and 4b (green). These may be a shielded box or a shielded room, that involve three main contributions as EMC protective device. Firstly, conductive box is aimed as local potential reference, for any circuit or electronic equipment housed inside. Secondly, each box behaves as a shielding against, outer incoming electromagnetic fields interference. Thirdly, on each metal shell, are flowing, collected currents which are diverted toward the ground potential reference (earth or large metal body). Generally speaking, it can be recalled, that concepts of local potential...