Electromechanical relays are still irreplaceable for switching operations of high-current load devices. This ranges from small switching relays for automotive applications to large contactors for jointing whole feeder branches in the main grid. In any case an extreme change of the resistance occurs in the relays switched circuit. This process is often accompanied by electric sparks or even electric arc ignitions, which may lead to impulses of high amplitude and short rise times. This induces broadband and high-frequency noise voltages, which spread on the respective wiring network. Modeling this problem in the field of automotive applications using SPICE serves here as an excellent example for EMC relevant phenomena.
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