Hi,
Suppose I have a coupling capacitor in front of a buffer opamp, how do I find the impedance required for calculating the 3dB frequency? Is the impedance of interest defined only by the stuff after the capacitor or also the stuff in front of it?
To keep it simple I will assume the buffer impedance to be a resistance, Rbuffer. Per attached image I might think that the impedance of the upper configuration is R1 + (R2 * Rbuffer / (R2 + Rbuffer)) and the impedance of the lower configuration might be just Rbuffer.
Suppose I have a coupling capacitor in front of a buffer opamp, how do I find the impedance required for calculating the 3dB frequency? Is the impedance of interest defined only by the stuff after the capacitor or also the stuff in front of it?
To keep it simple I will assume the buffer impedance to be a resistance, Rbuffer. Per attached image I might think that the impedance of the upper configuration is R1 + (R2 * Rbuffer / (R2 + Rbuffer)) and the impedance of the lower configuration might be just Rbuffer.
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