Hi, I was searching google for answers about my problem and stumbled upon this forum. So I'll post my problem here and hope that some friendly soul can help me :) I need to do a node-analysis of the circuit that I've attached here. The opamp is ideal so Ri=inf and R0=0 and A=inf. I end up with 3 equations for the nodes v1,v2: eq1: (1/(1/jwC1)+1/R1)v1 = Uin/(1/jwC1) eq2: (1/R3 + 1/(1/jwC2))v2 = Av1/R3 eq3: Uout=Av2 I am pretty sure I've done wrong in the node analysis, but I am unable to find out what I've done wrong (or right ;)). The equations I get later by solving the equationsystems doesn't add up. Any input or help on this problem is greatly appreciated!