# Integrator circuit

After applying square wave as input to integrator circuit,I did not got a triangular wave as output.It was like capacitor's charging and discharging curve.What is the reason of not getting a pure triangular wave. The feedback capacitor also has a feedback resistor in parallel.

• Please add a more information, such as schematic diagram. As is, there is to little information to diagnose the problem. – Greg Apr 22 '14 at 16:38

Without the resistor or some other feedback mechanism, the DC conditions of the op-amp are unstable. Note how large R2 is and you should aim to make R2 as large as possible but stuff conspires against you. For instance, the input offset currents of the device may be 10nA and if you are AC coupling the input, it will produce an error voltage on the output that is $I_{OFFSET} \times R_2$ = 0.1V.