Each electrical and electronic equipment is in practice exposed to disturbing influences. Disturbance can be classified from different perspectives. Depending on the nature we distinguish: noise, impulse disturbances and transients. In the last decade with the boom in electronics has increased the importance of high frequency disturbances, which, unlike the low-frequency is easily transmitted, whereas the disturbances ways are harder to define.
Electromagnetic compatibility (recompatibility), EMC, is defined as the ability of a device, system or appliance to show the correct operation even in environments, where operate other sources of electromagnetic signals (natural or artificial), while its own "electromagnetic action" does not approach their surroundings, ie. not emit any signals that would disturb other devices.
Disturbance is spreading by means of:
· galvanic coupling (conductive connection)
· capacitive and inductive coupling (applied between nearby conductors)
· electromagnetic field
Examples of electromagnetic disturbance according to its inception:
1. Industrial sources of disturbance
· high-current generators while producing the electric energy
· controlled semiconductor converters with high power ratings
Every electro technical equipment is simultaneously both, a source of electromagnetic interference, as well as its receiver working in a certain electromagnetic environment. For each such device defines a general standard CSN-IEC 01/01/1000 some fundamental terms, whose primary relationship is illustrated in the picture below