I've come across an audio amplifier circuit that contains this following configuration: enter image description here

I recognize R1,C1, and R3 to be part of a first order high pass filter, but I'm not sure what C2 and R2 are for. Does it filter high frequencies?

  • 3
    \$\begingroup\$ Where is C3? I don't see it on your schematic. \$\endgroup\$ – Elliot Alderson Sep 28 '18 at 14:50
  • \$\begingroup\$ I'm sorry, I meant R3 \$\endgroup\$ – Rico Cahyadi Sep 28 '18 at 15:00

R2 and C2 form a first order low pass filter, the cut off frequency is \$ Fc = \dfrac{1}{ 2 \pi R C}\$ where \$R\$ is in Ohms, and \$C\$ is in Farads, so yes, it filters high frequencies.

C1 is probably for ac coupling the opamp, which is an inverting amplifier with output\$Vout = -\dfrac{R3}{R1} * Vin\$


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