6. Complementary shielding protection

As mentioned in the first paragraph, complementary protection is excluded from the topological boundary, insofar as it does not constitute shielding, or an -arrangement that significantly attenuates electromagnetic stress. The functions performed by complementary protection are primarily intended to avoid the need for high-immunity shielding. The latter are costly and sometimes vulnerable in the long term.

As we briefly mentioned in the previous chapter, the high attenuation provided by high-immunity shields can be degraded by mechanical stresses caused by vibration, or by the appearance of contact resistances resulting from chemical attack (oxidation). As we shall see, amplitude limiters enable us to reconcile the use of ordinary shields exposed to intense transient electrical stress. As for ferrite rings, discussed in chapter