ABSTRACT
The first step is to find the filter type needed for the application. The listings in Sec. 5.8 should help. Either through documentation from the EMI test house or mathematically from sections of Chapter 11, the required insertion loss must be known. Often, this is given as a list of frequencies and the required loss at each. The filter must be checked at each frequency to make sure the loss is met at each frequency. The load current input voltage and the line frequency must be known to get the design impedance, Rd, and to find the minimum cutoff frequency. Figure out the value of Rd by dividing the voltage by the expected highest load current, and the cutoff frequency should be 10 times the line frequency.
