/diy/ - Do It Yourself

>>2034748
>>2034690
oops, my bad, the RC filter I wanted to show in the electret mic example is actually composed of the C and Rl, the load resistor on the output that establishes the dc level, that wasn't shown in the original drawing. pic
properly considered, the bias resistor Rb is part of the input impedance and placed in series with C. the resulting transfer function becomes Vout = Vin * (Rl/(Rb+Xc+Rl)), but since Rb is typically small (5k) compared to Rl (50k-100k) and the exact corner frequency is not particularly critical, it can be neglected in practice in this application