A demonstrator for EMC design training

Training in EMC design principles is enhanced if the participants can actually see the effect of good versus poor practice in areas which may be at the fringes of their own particular discipline. The paper describes a demonstration vehicle for showing to a class, using a spectrum analyzer and suitable transducers, the effect of various changes in layout and connections. The vehicle is a battery powered digital RF generator whose output has a number of connection options. Different layouts of the same circuit demonstrate the effect of PCB layout changes on radiated emissions. Connections of different cable types then demonstrate the crucial role that common mode cable currents have on determining the overall radiated emission profile. The undesirability of a `pigtail´ screened cable termination is also shown