[sdiy] Sallen-Key math question

[Jim Patchell]

    If the R's and C's are equal Wc = 1/RC,  If they are not equal then
Wc = SQRT(1/R1R2C1C2)

    Also note Wc = Fc * 2 * PI

    Please note, this was done from memory...

    -Jim

Scott Gravenhorst wrote:

> I keep looking at the math for this filter in the
> Lancaster's "Active Filter Cookbook" and frankly,
> I just don't get it.  What I'm after is given a
> cap of size C and a resistor of R ohms, what is
> Fc ?  The diagram clearly shows how to calculate
> R for a given Q value, but I don't see how to get
> Fc.
>
> Is there a better source of info for this ?
>
> NOTE:  I am NOT an EE.
>
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