kicad/pcb_calculator/attenuators/pi_formula.md

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### Pi Attenuator
___a___ is attenuation in dB<br>
___Z<sub>in</sub>___ is desired input impedance in &#x2126;<br>
___Z<sub>out</sub>___ is desired output impedance in &#x2126;<br>
___L = 10<sup>a/20</sup>___<br>
___A = (L+1) / (L&minus;1)___<br><br>
___R<sub>2</sub> = (L&minus;1) / 2&middot;&radic;(Z<sub>in</sub> &middot; Z<sub>out</sub> / L)___<br>
___R<sub>1</sub> = 1 / (A/Z<sub>in</sub> &minus; 1/R<sub>2</sub>)___<br>
___R<sub>3</sub> = 1 / (A/Z<sub>out</sub> &minus; 1/R<sub>2</sub>)___