An operational amplifier integrator circuit can be constructed by reversing the feedback resistor and input capacitor in a differentiator circuit (see Figure 2-24)
The resistor (R I) is the input component and the capacitor (C I) is the feedback component. However, if the low-frequency gain of the circuit is not limited, the dc offset
In this circuit, a shunt resistor (RS) is connected across feedback capacitor C I to limit the low-frequency gain of the circuit. The de offset (due to the input bias current) is minimized by connecting resistor R2 between the noninverting input and ground. Resistor R2 is equal to the parallel combination of RI and shunt resistor RS. The shunt resistor helps limit the circuit low-frequency gain for input frequencies greater than those determined by the following equation.