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Hey guys, Could you shed a little light on this problem here? I'm trying to calculate the half power frequency for these 2 circuits, and I'm not sure if my reasoning/math is right: For the former one, I did Fc=1/(2πR*C) where R=(R1*R2)/(R1+R2)+R3. Is this correct? Is this all? How about the latter one? Thank you
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Hello Benny, You have to look from the capacitor into the circuit when you calculate the corner frequency or the time constant. Treat the voltage source as a short (0Ohm) for the calculation, because it has zero internal resistance. a) Lowpass Filter fc = 1/(2*pi*R*C) R = 1/(1/R1 + 1/R2 + 1/R3) b) Highpass Filter fc = 1/(2*pi*R*C) R = R1 + 1/(1/R2 + 1/R3) By the way you can simulate this circuit with LTspice to check the results. Best regards, Helmut