# impedance of an sine wave circuit

I would like to get some help with the calculation and modeling of the attached circuit. this circuit is supposed to generate a 159.15 Hz sine wave(according to formula), i want to connect the output of the circuit to a transformer with minimal losses of voltage, for that i need that the output impedance of the circuit(which is also the output of the op-amp 741) would be as low as possible.

I know that ideal op-amp output impedance is 0, but how do i calculate the actual impedance of the circuit(Rout) ? and how to i model the opamp in the circuit ? if i suppose to model the opamp according to the pic below how do i calculate the inputs?(v±) when solving these circuits i usually start with KCL from a voltage source summing up all elements until i get to ground but how do start the calculation if it is a feedback circuit like this.

frequency formula: 1/2*pi*R1*R2*C1*C2 while C1=C2=0.1*10^6 [F], R1=1K[ohm],R2=100K[Ohm]

the impedance of C1 and C2 is 1000 [Ohm],

• Negative feedback lowers the output impedance of the opamp. You cannot simply apply KCL etc and get the correct result. In this case there's more to it. Study feedback circuits if you want to understand how this works. – Bimpelrekkie Oct 24 '15 at 14:49 