What is Low Pass RC Filter?

A low pass filter allows all low frequency signals to pass from DC (0Hz) up to its corner frequency, (¦c) and blocks all high frequency signals above this point. A first-order RC low pass filter is constructed as follows:

\[A=\frac{Vout}{Vin}=\frac{Xc}{Z}=\frac{Xc}{\sqrt{R^2+Xc^2}}\]

\[A=\frac{1}{\sqrt{1^2+(ωRc)^2}}\]

`fc=\frac{1}{2\piRC}` or  `ωc=\frac{1}{RC}`

\[Af=-3dB=\frac{1}{\sqrt{2}}=0.7071Vin\]
Roll -off = -20dB/Decade
or -6dB/OctaveLOW PASS RC FILTER