EMC Measures
Filtering Filter A filter comprises components such as capacitors, chokes or ferrite cores and are integrated in a circuit. Filters should only let useful signals through and suppress undesired parts of the transferred signal as much as possible. Filters are used for different purposes: To protect the power supply network against interference through the devices Protect devices from interference from the power supply network Protect circuits against interferences from devices within the circuit
How filters work Useful signals and undesired signals are superposed at the filters input, only the useful signal is transferred to the output. The filtered out undesired signal is dissipated via the ground connection.
Filter types There are the following filter types: Filter for common-mode interference Filter for differential mode disturbance Combined filter for differential and common-mode interferences
Ferrite cores Ferrite cores are filters for high frequency common mode interferences. The are made from materials with high magnetic permeability. Ferrite cores work on two principles: Inductivity against common interference currents Absorption of the induced high frequency interference current using simultaneous energy release (warming up)
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