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Old 06-25-2009, 05:52 AM
Petrucciowns Petrucciowns is offline
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Default RL High-Pass/ Low-Pass Filters

Does anyone know the formula to find the cutoff frequency for an RL High-Pass/ Low-Pass Filter?

I know with RC filters it's 1/ (2ΩRC) ,but this does not work for RL filters.
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Old 06-25-2009, 05:07 PM
Petrucciowns Petrucciowns is offline
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I figured it out, but if anyone is ever looking for it it's:

Fc (Cutoff frequency) = R/ ( 2ΩL)
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Old 06-25-2009, 06:59 PM
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PRS PRS is offline
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I believe its f = 1/(2*pi*R*L)
Yakima, Washington
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Old 06-25-2009, 11:08 PM
Petrucciowns Petrucciowns is offline
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Thanks for the reply. I already tried that one. It calculates the cutoff frequency of and RC filter. The one I listed above calculates the cutoff frequency of an RL filter.
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Old 06-26-2009, 06:11 PM
Jony130 Jony130 is online now
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Well, of course the cut-off frequency is when XL=R
And the time constant for LR circut is L/R
Therefore, the cut-off frequency, no matter if High-Pass/ Low-Pass
fc = R/(2•Π•L)

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